From d8b8559c2eb0b89379193567cea49e4783e0bc8d Mon Sep 17 00:00:00 2001
From: Deukhoofd <Deukhoofd@gmail.com>
Date: Sat, 29 Jul 2023 12:57:52 +0200
Subject: [PATCH] Basic implementation of evolutions

---
 .../libraries/evolution_library.rs            |  57 +++++++++
 src/dynamic_data/libraries/mod.rs             |   2 +
 src/dynamic_data/models/pokemon.rs            |  14 ++-
 .../serialization/serialized_pokemon.rs       |   3 +
 .../script_handling/item_script.rs            |   4 +-
 src/dynamic_data/script_handling/script.rs    |   4 +-
 src/ffi/ffi_handle.rs                         |   6 +-
 src/ffi/static_data/ability.rs                |   8 +-
 src/ffi/static_data/mod.rs                    |  44 +++----
 src/ffi/static_data/move_data.rs              |   7 +-
 src/ffi/static_data/species.rs                |   2 +
 .../wasm/export_registry/mod.rs               |  40 +++---
 .../export_registry/static_data/ability.rs    |   4 +-
 .../wasm/export_registry/wasm_object.rs       |   8 +-
 .../wasm/item_script.rs                       |   6 +-
 src/script_implementations/wasm/script.rs     |   6 +-
 src/static_data/libraries/species_library.rs  |   2 +
 src/static_data/mod.rs                        |  28 ++---
 src/static_data/moves/secondary_effect.rs     |  12 +-
 src/static_data/species_data/ability.rs       |  12 +-
 .../species_data/evolution_data.rs            | 118 +++++++++++++++++
 src/static_data/species_data/mod.rs           |   4 +
 src/static_data/species_data/species.rs       |  24 ++++
 tests/common/library_loader.rs                | 119 ++++++++++++++++--
 tests/data/Pokemon.json                       |  18 ++-
 25 files changed, 437 insertions(+), 115 deletions(-)
 create mode 100644 src/dynamic_data/libraries/evolution_library.rs
 create mode 100644 src/static_data/species_data/evolution_data.rs

diff --git a/src/dynamic_data/libraries/evolution_library.rs b/src/dynamic_data/libraries/evolution_library.rs
new file mode 100644
index 0000000..a5dc14c
--- /dev/null
+++ b/src/dynamic_data/libraries/evolution_library.rs
@@ -0,0 +1,57 @@
+use crate::dynamic_data::Pokemon;
+use crate::static_data::{EvolutionMethod, TimeOfDay};
+
+/// A library for handling the checking of evolution requirements.
+pub trait EvolutionLibrary {
+    /// Checks if the given Pokemon fulfills the given evolution conditions.
+    fn pokemon_fulfills_evolution_conditions(&self, pokemon: &Pokemon, method: &EvolutionMethod) -> bool;
+}
+
+/// A standard implementation of the Evolution Library.
+pub struct EvolutionLibraryImpl;
+
+impl EvolutionLibrary for EvolutionLibraryImpl {
+    fn pokemon_fulfills_evolution_conditions(&self, pokemon: &Pokemon, method: &EvolutionMethod) -> bool {
+        match method {
+            EvolutionMethod::Level { level } => pokemon.level() >= *level,
+            EvolutionMethod::LevelGender { level, gender } => pokemon.level() >= *level && pokemon.gender() == *gender,
+            EvolutionMethod::Item { .. } => false,
+            EvolutionMethod::ItemGender { .. } => false,
+            EvolutionMethod::HoldItem { item } => pokemon.has_held_item(item),
+            EvolutionMethod::DayHoldItem { item } => {
+                let time_of_day = pokemon.library().misc_library().time_of_day();
+                pokemon.has_held_item(item) && time_of_day == TimeOfDay::Morning || time_of_day == TimeOfDay::Day
+            }
+            EvolutionMethod::NightHoldItem { item } => {
+                let time_of_day = pokemon.library().misc_library().time_of_day();
+                pokemon.has_held_item(item) && time_of_day == TimeOfDay::Evening || time_of_day == TimeOfDay::Night
+            }
+            EvolutionMethod::HasMove { move_name } => pokemon
+                .learned_moves()
+                .read()
+                .iter()
+                .any(|learned_move| learned_move.as_ref().is_some_and(|v| v.move_data().name() == move_name)),
+            EvolutionMethod::Happiness { happiness } => pokemon.happiness() >= *happiness,
+            EvolutionMethod::HappinessDay { happiness } => {
+                let time_of_day = pokemon.library().misc_library().time_of_day();
+                pokemon.happiness() >= *happiness && time_of_day == TimeOfDay::Morning || time_of_day == TimeOfDay::Day
+            }
+            EvolutionMethod::HappinessNight { happiness } => {
+                let time_of_day = pokemon.library().misc_library().time_of_day();
+                pokemon.happiness() >= *happiness && time_of_day == TimeOfDay::Evening
+                    || time_of_day == TimeOfDay::Night
+            }
+            EvolutionMethod::Trade => false,
+            EvolutionMethod::TradeSpecies { .. } => false,
+            EvolutionMethod::TradeItem { .. } => false,
+            EvolutionMethod::Location { .. } => {
+                // TODO: Implement this.
+                false
+            }
+            EvolutionMethod::Custom { .. } => {
+                // TODO: Implement this.
+                false
+            }
+        }
+    }
+}
diff --git a/src/dynamic_data/libraries/mod.rs b/src/dynamic_data/libraries/mod.rs
index 398a98a..9ce6105 100755
--- a/src/dynamic_data/libraries/mod.rs
+++ b/src/dynamic_data/libraries/mod.rs
@@ -19,3 +19,5 @@ pub(crate) mod dynamic_library;
 mod misc_library;
 /// Data for dynamically resolving scripts during battles.
 mod script_resolver;
+/// Handling for checking evolution requirements.
+mod evolution_library;
diff --git a/src/dynamic_data/models/pokemon.rs b/src/dynamic_data/models/pokemon.rs
index 0dde446..1fcfa1b 100755
--- a/src/dynamic_data/models/pokemon.rs
+++ b/src/dynamic_data/models/pokemon.rs
@@ -68,6 +68,9 @@ struct PokemonData {
     /// The height of the Pokemon in meters.
     height: Atomic<f32>,
 
+    /// The happiness of the Pokemon. Also known as friendship.
+    happiness: AtomicU8,
+
     /// The stats of the Pokemon when disregarding any stat boosts.
     flat_stats: Arc<StatisticSet<u32>>,
     /// The statistics boosts of the Pokemon. Will prevent the value from going above 6, and below
@@ -158,6 +161,7 @@ impl Pokemon {
             .calculate_experience(species.growth_rate(), level)?;
         let weight = form.weight();
         let height = form.height();
+        let base_happiness = species.base_happiness();
         let nature = library
             .static_data()
             .natures()
@@ -198,6 +202,7 @@ impl Pokemon {
             status_script: ScriptContainer::default(),
             volatile: Default::default(),
             script_source_data: Default::default(),
+            happiness: AtomicU8::new(base_happiness),
         };
 
         let pokemon = Self {
@@ -326,11 +331,16 @@ impl Pokemon {
     pub fn set_weight(&self, weight: f32) {
         self.data.weight.store(weight, Ordering::Relaxed)
     }
-
     /// The height of the Pokemon in meters.
     pub fn height(&self) -> f32 {
         self.data.height.load(Ordering::Relaxed)
     }
+
+    /// The current happiness of the Pokemon. Also known as friendship.
+    pub fn happiness(&self) -> u8 {
+        self.data.happiness.load(Ordering::Relaxed)
+    }
+
     /// An optional nickname of the Pokemon.
     pub fn nickname(&self) -> &Option<String> {
         &self.data.nickname
@@ -921,6 +931,7 @@ impl Pokemon {
                 current_health: AtomicU32::new(value.current_health),
                 weight: Atomic::new(value.weight),
                 height: Atomic::new(value.height),
+                happiness: AtomicU8::new(value.happiness),
                 flat_stats: Arc::new(Default::default()),
                 stat_boost: Arc::new(value.stat_boosts.clone()),
                 boosted_stats: Arc::new(Default::default()),
@@ -1163,6 +1174,7 @@ pub mod test {
             });
             species.expect_growth_rate().return_const(StringKey::empty());
             species.expect_name().return_const(StringKey::new("test_species"));
+            species.expect_base_happiness().return_const(100);
 
             let s: Arc<dyn Species> = Arc::new(species);
             Some(s)
diff --git a/src/dynamic_data/models/serialization/serialized_pokemon.rs b/src/dynamic_data/models/serialization/serialized_pokemon.rs
index 6226f33..dee6ffc 100644
--- a/src/dynamic_data/models/serialization/serialized_pokemon.rs
+++ b/src/dynamic_data/models/serialization/serialized_pokemon.rs
@@ -34,6 +34,8 @@ pub struct SerializedPokemon {
     pub weight: f32,
     /// The height of the Pokemon.
     pub height: f32,
+    /// The happiness of the Pokemon.
+    pub happiness: u8,
     /// The stat boosts of the Pokemon.
     pub stat_boosts: ClampedStatisticSet<i8, -6, 6>,
     /// The individual values of the Pokemon.
@@ -101,6 +103,7 @@ impl Into<anyhow_ext::Result<SerializedPokemon>> for &Pokemon {
             current_health: self.current_health(),
             weight: self.weight(),
             height: self.height(),
+            happiness: self.happiness(),
             stat_boosts: self.stat_boosts().deref().deref().clone(),
             individual_values: self.individual_values().deref().deref().clone(),
             effort_values: self.effort_values().deref().deref().clone(),
diff --git a/src/dynamic_data/script_handling/item_script.rs b/src/dynamic_data/script_handling/item_script.rs
index 14459ce..41a4228 100755
--- a/src/dynamic_data/script_handling/item_script.rs
+++ b/src/dynamic_data/script_handling/item_script.rs
@@ -1,11 +1,11 @@
 use crate::dynamic_data::Pokemon;
-use crate::static_data::EffectParameter;
+use crate::static_data::Parameter;
 use std::sync::Arc;
 
 /// The script functions that are relevant to item use.
 pub trait ItemScript {
     /// Initializes the script with the given parameters for a specific item
-    fn on_initialize(&self, _pars: Vec<Arc<EffectParameter>>) -> anyhow_ext::Result<()> {
+    fn on_initialize(&self, _pars: Vec<Arc<Parameter>>) -> anyhow_ext::Result<()> {
         Ok(())
     }
 
diff --git a/src/dynamic_data/script_handling/script.rs b/src/dynamic_data/script_handling/script.rs
index da88d33..b97a45f 100755
--- a/src/dynamic_data/script_handling/script.rs
+++ b/src/dynamic_data/script_handling/script.rs
@@ -13,8 +13,8 @@ use crate::dynamic_data::{Battle, DynamicLibrary};
 use crate::dynamic_data::{BattleSide, DamageSource};
 use crate::dynamic_data::{ExecutingMove, WeakBattleReference, WeakPokemonReference};
 use crate::dynamic_data::{Pokemon, WeakBattleSideReference};
-use crate::static_data::{EffectParameter, TypeIdentifier};
 use crate::static_data::{Item, Statistic};
+use crate::static_data::{Parameter, TypeIdentifier};
 use crate::StringKey;
 
 /// The script trait is used to make changes to how a battle executes, without requiring hardcoded
@@ -69,7 +69,7 @@ pub trait Script: Send + Sync {
         Ok(())
     }
     /// This function is ran when this script starts being in effect.
-    fn on_initialize(&self, _library: &Arc<dyn DynamicLibrary>, _pars: Vec<Arc<EffectParameter>>) -> Result<()> {
+    fn on_initialize(&self, _library: &Arc<dyn DynamicLibrary>, _pars: Vec<Arc<Parameter>>) -> Result<()> {
         Ok(())
     }
     /// This function is ran just before the start of the turn. Everyone has made its choices here,
diff --git a/src/ffi/ffi_handle.rs b/src/ffi/ffi_handle.rs
index 91bf6b6..e1e8c9f 100644
--- a/src/ffi/ffi_handle.rs
+++ b/src/ffi/ffi_handle.rs
@@ -1,5 +1,5 @@
 use crate::static_data::{
-    Ability, EffectParameter, Form, GrowthRate, Item, LearnableMoves, MoveData, Nature, SecondaryEffect, Species,
+    Ability, Form, GrowthRate, Item, LearnableMoves, MoveData, Nature, Parameter, SecondaryEffect, Species,
     StaticStatisticSet, StatisticSet,
 };
 use anyhow::anyhow;
@@ -60,7 +60,7 @@ impl<T> Default for FFIHandle<T> {
 #[allow(clippy::missing_docs_in_private_items)] // I'm not documenting these items.
 pub(super) enum FFIObject {
     Ability(Arc<dyn Ability>),
-    EffectParameter(Arc<EffectParameter>),
+    EffectParameter(Arc<Parameter>),
     StatisticSetU8(Arc<StatisticSet<u8>>),
     StatisticSetI8(Arc<StatisticSet<i8>>),
     StatisticSetU32(Arc<StatisticSet<u32>>),
@@ -307,7 +307,7 @@ macro_rules! ffi_obj_conversions {
 }
 
 ffi_obj_conversions!(Arc<dyn Ability>, Ability);
-ffi_obj_conversions!(Arc<EffectParameter>, EffectParameter);
+ffi_obj_conversions!(Arc<Parameter>, EffectParameter);
 ffi_obj_conversions!(Arc<StatisticSet<i8>>, StatisticSetI8);
 ffi_obj_conversions!(Arc<StatisticSet<u8>>, StatisticSetU8);
 ffi_obj_conversions!(Arc<StatisticSet<u32>>, StatisticSetU32);
diff --git a/src/ffi/static_data/ability.rs b/src/ffi/static_data/ability.rs
index 8879955..43f1f89 100644
--- a/src/ffi/static_data/ability.rs
+++ b/src/ffi/static_data/ability.rs
@@ -1,7 +1,7 @@
 use crate::ffi::FFIHandle;
 use crate::ffi::FromFFIHandle;
 use crate::ffi::{FFIResult, OwnedPtrString};
-use crate::static_data::{Ability, AbilityImpl, EffectParameter};
+use crate::static_data::{Ability, AbilityImpl, Parameter};
 use crate::StringKey;
 use anyhow::anyhow;
 use std::ffi::{c_char, CStr, CString};
@@ -12,11 +12,11 @@ use std::sync::Arc;
 unsafe extern "C" fn ability_new(
     name: *const c_char,
     effect: *const c_char,
-    parameters: *const FFIHandle<Arc<EffectParameter>>,
+    parameters: *const FFIHandle<Arc<Parameter>>,
     parameters_length: usize,
 ) -> FFIResult<FFIHandle<Arc<dyn Ability>>> {
     let parameters = std::slice::from_raw_parts(parameters, parameters_length);
-    let mut parameters_vec: Vec<Arc<EffectParameter>> = Vec::with_capacity(parameters_length);
+    let mut parameters_vec: Vec<Arc<Parameter>> = Vec::with_capacity(parameters_length);
     for parameter in parameters {
         parameters_vec.push(parameter.from_ffi_handle());
     }
@@ -63,7 +63,7 @@ unsafe extern "C" fn ability_parameter_length(ptr: FFIHandle<Arc<dyn Ability>>)
 unsafe extern "C" fn ability_parameter_get(
     ptr: FFIHandle<Arc<dyn Ability>>,
     index: usize,
-) -> FFIHandle<Arc<EffectParameter>> {
+) -> FFIHandle<Arc<Parameter>> {
     if let Some(p) = ptr.from_ffi_handle().parameters().get(index) {
         FFIHandle::get_handle(p.clone().into())
     } else {
diff --git a/src/ffi/static_data/mod.rs b/src/ffi/static_data/mod.rs
index 88c89c1..2d90be3 100644
--- a/src/ffi/static_data/mod.rs
+++ b/src/ffi/static_data/mod.rs
@@ -1,6 +1,6 @@
 use crate::ffi::ffi_handle::{FFIHandle, FFIObject, FromFFIHandle};
 use crate::ffi::{FFIResult, OwnedPtrString};
-use crate::static_data::EffectParameter;
+use crate::static_data::Parameter;
 use crate::{PkmnError, StringKey};
 use anyhow::anyhow;
 use std::ffi::{c_char, CStr, CString};
@@ -30,50 +30,50 @@ mod statistic_set;
 
 /// Instantiates an effect parameter with a boolean.
 #[no_mangle]
-extern "C" fn effect_parameter_new_bool(value: u8) -> FFIHandle<Arc<EffectParameter>> {
-    FFIHandle::get_handle(FFIObject::EffectParameter(Arc::new(EffectParameter::from(value == 1))))
+extern "C" fn effect_parameter_new_bool(value: u8) -> FFIHandle<Arc<Parameter>> {
+    FFIHandle::get_handle(FFIObject::EffectParameter(Arc::new(Parameter::from(value == 1))))
 }
 
 /// Instantiates an effect parameter with an integer.
 #[no_mangle]
-extern "C" fn effect_parameter_new_int(value: i64) -> FFIHandle<Arc<EffectParameter>> {
-    FFIHandle::get_handle(FFIObject::EffectParameter(Arc::new(EffectParameter::from(value))))
+extern "C" fn effect_parameter_new_int(value: i64) -> FFIHandle<Arc<Parameter>> {
+    FFIHandle::get_handle(FFIObject::EffectParameter(Arc::new(Parameter::from(value))))
 }
 
 /// Instantiates an effect parameter with a float.
 #[no_mangle]
-extern "C" fn effect_parameter_new_float(value: f32) -> FFIHandle<Arc<EffectParameter>> {
-    FFIHandle::get_handle(FFIObject::EffectParameter(Arc::new(EffectParameter::from(value))))
+extern "C" fn effect_parameter_new_float(value: f32) -> FFIHandle<Arc<Parameter>> {
+    FFIHandle::get_handle(FFIObject::EffectParameter(Arc::new(Parameter::from(value))))
 }
 
 /// Instantiates an effect parameter with a string.
 #[no_mangle]
-unsafe extern "C" fn effect_parameter_new_string(value: *const c_char) -> FFIResult<FFIHandle<Arc<EffectParameter>>> {
+unsafe extern "C" fn effect_parameter_new_string(value: *const c_char) -> FFIResult<FFIHandle<Arc<Parameter>>> {
     let sk: StringKey = match CStr::from_ptr(value).to_str() {
         Ok(sk) => sk.into(),
         Err(_) => return FFIResult::err(PkmnError::InvalidCString.into()),
     };
     FFIResult::ok(FFIHandle::get_handle(FFIObject::EffectParameter(Arc::new(
-        EffectParameter::from(sk),
+        Parameter::from(sk),
     ))))
 }
 
 /// Get the type of an effect parameter.
 #[no_mangle]
-extern "C" fn effect_parameter_get_type(ptr: FFIHandle<Arc<EffectParameter>>) -> u8 {
+extern "C" fn effect_parameter_get_type(ptr: FFIHandle<Arc<Parameter>>) -> u8 {
     match ptr.from_ffi_handle().deref() {
-        EffectParameter::Bool(_) => 0,
-        EffectParameter::Int(_) => 1,
-        EffectParameter::Float(_) => 2,
-        EffectParameter::String(_) => 3,
+        Parameter::Bool(_) => 0,
+        Parameter::Int(_) => 1,
+        Parameter::Float(_) => 2,
+        Parameter::String(_) => 3,
     }
 }
 
 /// Get the boolean contained in the effect parameter, panics if the effect parameter is not a bool.
 #[no_mangle]
-extern "C" fn effect_parameter_get_as_bool(ptr: FFIHandle<Arc<EffectParameter>>) -> FFIResult<u8> {
+extern "C" fn effect_parameter_get_as_bool(ptr: FFIHandle<Arc<Parameter>>) -> FFIResult<u8> {
     let p = ptr.from_ffi_handle();
-    if let EffectParameter::Bool(b) = p.deref() {
+    if let Parameter::Bool(b) = p.deref() {
         FFIResult::ok(u8::from(*b))
     } else {
         FFIResult::err(anyhow!("Unexpected effect parameter. Expected bool, was: {}", p))
@@ -82,9 +82,9 @@ extern "C" fn effect_parameter_get_as_bool(ptr: FFIHandle<Arc<EffectParameter>>)
 
 /// Get the int contained in the effect parameter, panics if the effect parameter is not a int.
 #[no_mangle]
-extern "C" fn effect_parameter_get_as_int(ptr: FFIHandle<Arc<EffectParameter>>) -> FFIResult<i64> {
+extern "C" fn effect_parameter_get_as_int(ptr: FFIHandle<Arc<Parameter>>) -> FFIResult<i64> {
     let p = ptr.from_ffi_handle();
-    if let EffectParameter::Int(b) = p.deref() {
+    if let Parameter::Int(b) = p.deref() {
         FFIResult::ok(*b)
     } else {
         FFIResult::err(anyhow!("Unexpected effect parameter. Expected int, was: {}", p))
@@ -93,9 +93,9 @@ extern "C" fn effect_parameter_get_as_int(ptr: FFIHandle<Arc<EffectParameter>>)
 
 /// Get the float contained in the effect parameter, panics if the effect parameter is not a float.
 #[no_mangle]
-extern "C" fn effect_parameter_get_as_float(ptr: FFIHandle<Arc<EffectParameter>>) -> FFIResult<f32> {
+extern "C" fn effect_parameter_get_as_float(ptr: FFIHandle<Arc<Parameter>>) -> FFIResult<f32> {
     let p = ptr.from_ffi_handle();
-    if let EffectParameter::Float(b) = p.deref() {
+    if let Parameter::Float(b) = p.deref() {
         FFIResult::ok(*b)
     } else {
         FFIResult::err(anyhow!("Unexpected effect parameter. Expected float, was: {}", p))
@@ -104,9 +104,9 @@ extern "C" fn effect_parameter_get_as_float(ptr: FFIHandle<Arc<EffectParameter>>
 
 /// Get the string contained in the effect parameter, panics if the effect parameter is not a string.
 #[no_mangle]
-extern "C" fn effect_parameter_get_as_string(ptr: FFIHandle<Arc<EffectParameter>>) -> FFIResult<OwnedPtrString> {
+extern "C" fn effect_parameter_get_as_string(ptr: FFIHandle<Arc<Parameter>>) -> FFIResult<OwnedPtrString> {
     let p = ptr.from_ffi_handle();
-    if let EffectParameter::String(b) = p.deref() {
+    if let Parameter::String(b) = p.deref() {
         match CString::new(b.str().to_string()) {
             Ok(cstr) => FFIResult::ok(OwnedPtrString(cstr.into_raw())),
             Err(_) => FFIResult::err(PkmnError::InvalidCString.into()),
diff --git a/src/ffi/static_data/move_data.rs b/src/ffi/static_data/move_data.rs
index 55e949b..4d8ad72 100644
--- a/src/ffi/static_data/move_data.rs
+++ b/src/ffi/static_data/move_data.rs
@@ -1,8 +1,7 @@
 use crate::ffi::ffi_handle::{FFIHandle, FromFFIHandle};
 use crate::ffi::{ffi_handle_arc_dyn_getter, FFIResult, NonOwnedPtrString, OwnedPtrString};
 use crate::static_data::{
-    EffectParameter, MoveCategory, MoveData, MoveDataImpl, MoveTarget, SecondaryEffect, SecondaryEffectImpl,
-    TypeIdentifier,
+    MoveCategory, MoveData, MoveDataImpl, MoveTarget, Parameter, SecondaryEffect, SecondaryEffectImpl, TypeIdentifier,
 };
 use crate::StringKey;
 use anyhow::anyhow;
@@ -100,7 +99,7 @@ unsafe extern "C" fn move_data_has_flag(ptr: FFIHandle<Arc<dyn MoveData>>, flag:
 unsafe extern "C" fn secondary_effect_new(
     chance: f32,
     effect_name: NonOwnedPtrString,
-    parameters: *mut FFIHandle<Arc<EffectParameter>>,
+    parameters: *mut FFIHandle<Arc<Parameter>>,
     parameters_length: usize,
 ) -> FFIHandle<Box<dyn SecondaryEffect>> {
     let parameter_slice = std::slice::from_raw_parts(parameters, parameters_length);
@@ -148,7 +147,7 @@ unsafe extern "C" fn secondary_effect_parameter_length(ptr: FFIHandle<Arc<dyn Se
 unsafe extern "C" fn secondary_effect_parameter_get(
     ptr: FFIHandle<Arc<dyn SecondaryEffect>>,
     index: usize,
-) -> FFIHandle<Arc<EffectParameter>> {
+) -> FFIHandle<Arc<Parameter>> {
     if let Some(v) = ptr.from_ffi_handle().parameters().get(index) {
         FFIHandle::get_handle(v.clone().into())
     } else {
diff --git a/src/ffi/static_data/species.rs b/src/ffi/static_data/species.rs
index b210317..e7b475c 100644
--- a/src/ffi/static_data/species.rs
+++ b/src/ffi/static_data/species.rs
@@ -50,8 +50,10 @@ unsafe extern "C" fn species_new(
         gender_rate,
         &growth_rate,
         capture_rate,
+        120,
         default_form.clone(),
         flags_set,
+        Vec::new(),
     ));
     FFIResult::ok(FFIHandle::get_handle(a.into()))
 }
diff --git a/src/script_implementations/wasm/export_registry/mod.rs b/src/script_implementations/wasm/export_registry/mod.rs
index 116f219..895bc0c 100755
--- a/src/script_implementations/wasm/export_registry/mod.rs
+++ b/src/script_implementations/wasm/export_registry/mod.rs
@@ -6,7 +6,7 @@ use wasmer::{FunctionEnv, FunctionEnvMut, Imports, StoreMut};
 
 use crate::script_implementations::wasm::extern_ref::ExternRef;
 use crate::script_implementations::wasm::script_resolver::WebAssemblyEnv;
-use crate::static_data::EffectParameter;
+use crate::static_data::Parameter;
 use crate::StringKey;
 
 /// Dynamic data registration
@@ -140,51 +140,39 @@ fn string_key_get_str(env: FunctionEnvMut<WebAssemblyEnv>, string_key: ExternRef
 }
 
 /// Gets the type of an EffectParameter
-fn effect_parameter_get_type(
-    env: FunctionEnvMut<WebAssemblyEnv>,
-    parameter: ExternRef<EffectParameter>,
-) -> WasmResult<u8> {
+fn effect_parameter_get_type(env: FunctionEnvMut<WebAssemblyEnv>, parameter: ExternRef<Parameter>) -> WasmResult<u8> {
     let value = get_value_arc!(parameter, env);
     wasm_ok(match value.deref() {
-        EffectParameter::Bool(_) => 1,
-        EffectParameter::Int(_) => 2,
-        EffectParameter::Float(_) => 3,
-        EffectParameter::String(_) => 4,
+        Parameter::Bool(_) => 1,
+        Parameter::Int(_) => 2,
+        Parameter::Float(_) => 3,
+        Parameter::String(_) => 4,
     })
 }
 
 /// Gets the inner bool data of an EffectParameter. Panics if it's not a bool.
-fn effect_parameter_as_bool(
-    env: FunctionEnvMut<WebAssemblyEnv>,
-    parameter: ExternRef<EffectParameter>,
-) -> WasmResult<u8> {
+fn effect_parameter_as_bool(env: FunctionEnvMut<WebAssemblyEnv>, parameter: ExternRef<Parameter>) -> WasmResult<u8> {
     let value = get_value_arc!(parameter, env);
     match value.deref() {
-        EffectParameter::Bool(b) => wasm_ok(<u8 as From<bool>>::from(*b)),
+        Parameter::Bool(b) => wasm_ok(<u8 as From<bool>>::from(*b)),
         _ => wasm_err::<u8>(anyhow!("Unexpected parameter type. Expected bool, got {}", value), &env),
     }
 }
 
 /// Gets the inner int data of an EffectParameter. Panics if it's not an int.
-fn effect_parameter_as_int(
-    env: FunctionEnvMut<WebAssemblyEnv>,
-    parameter: ExternRef<EffectParameter>,
-) -> WasmResult<i64> {
+fn effect_parameter_as_int(env: FunctionEnvMut<WebAssemblyEnv>, parameter: ExternRef<Parameter>) -> WasmResult<i64> {
     let value = get_value_arc!(parameter, env);
     match value.deref() {
-        EffectParameter::Int(i) => wasm_ok(*i),
+        Parameter::Int(i) => wasm_ok(*i),
         _ => wasm_err::<i64>(anyhow!("Unexpected parameter type. Expected int, got {}", value), &env),
     }
 }
 
 /// Gets the inner float data of an EffectParameter. Panics if it's not a float.
-fn effect_parameter_as_float(
-    env: FunctionEnvMut<WebAssemblyEnv>,
-    parameter: ExternRef<EffectParameter>,
-) -> WasmResult<f32> {
+fn effect_parameter_as_float(env: FunctionEnvMut<WebAssemblyEnv>, parameter: ExternRef<Parameter>) -> WasmResult<f32> {
     let value = get_value_arc!(parameter, env);
     match value.deref() {
-        EffectParameter::Float(f) => wasm_ok(*f),
+        Parameter::Float(f) => wasm_ok(*f),
         _ => wasm_err::<f32>(
             anyhow!("Unexpected parameter type. Expected float, got {}", value),
             &env,
@@ -195,11 +183,11 @@ fn effect_parameter_as_float(
 /// Gets the inner string data of an EffectParameter. Panics if it's not a string.
 fn effect_parameter_as_string(
     env: FunctionEnvMut<WebAssemblyEnv>,
-    parameter: ExternRef<EffectParameter>,
+    parameter: ExternRef<Parameter>,
 ) -> WasmResult<ExternRef<StringKey>> {
     let value = get_value_arc!(parameter, env);
     match value.deref() {
-        EffectParameter::String(s) => wasm_ok(ExternRef::<StringKey>::func_new(&env, s.clone().into())),
+        Parameter::String(s) => wasm_ok(ExternRef::<StringKey>::func_new(&env, s.clone().into())),
         _ => wasm_err::<ExternRef<StringKey>>(
             anyhow!("Unexpected parameter type. Expected string, got {}", value),
             &env,
diff --git a/src/script_implementations/wasm/export_registry/static_data/ability.rs b/src/script_implementations/wasm/export_registry/static_data/ability.rs
index 0571a32..621cdfb 100644
--- a/src/script_implementations/wasm/export_registry/static_data/ability.rs
+++ b/src/script_implementations/wasm/export_registry/static_data/ability.rs
@@ -3,7 +3,7 @@ use crate::script_implementations::wasm::export_registry::FunctionEnvMut;
 use crate::script_implementations::wasm::export_registry::{register, try_wasm, wasm_ok, WasmResult};
 use crate::script_implementations::wasm::extern_ref::ExternRef;
 use crate::script_implementations::wasm::script_resolver::WebAssemblyEnv;
-use crate::static_data::{Ability, EffectParameter};
+use crate::static_data::{Ability, Parameter};
 use crate::StringKey;
 
 register! {
@@ -32,7 +32,7 @@ fn ability_get_parameters(
     let parameters = ability.parameters();
     let mut vec : Vec<u32> = Vec::with_capacity(parameters.len());
     for parameter in parameters {
-        vec.push(ExternRef::<EffectParameter>::func_new(&env, parameter.into()).index() as u32);
+        vec.push(ExternRef::<Parameter>::func_new(&env, parameter.into()).index() as u32);
     }
     let wasm_ptr = try_wasm!(env.data().data().copy_value_vec_to_wasm(&vec), env);
     let r: u64 = unsafe { std::mem::transmute((wasm_ptr, vec.len() as u32)) };
diff --git a/src/script_implementations/wasm/export_registry/wasm_object.rs b/src/script_implementations/wasm/export_registry/wasm_object.rs
index dd2a9ab..9903dd0 100644
--- a/src/script_implementations/wasm/export_registry/wasm_object.rs
+++ b/src/script_implementations/wasm/export_registry/wasm_object.rs
@@ -9,7 +9,7 @@ use std::sync::{Arc, Weak};
 pub(crate) enum WasmObject {
     // Static data
     StringKey(crate::StringKey),
-    EffectParameter(Weak<crate::static_data::EffectParameter>),
+    EffectParameter(Weak<crate::static_data::Parameter>),
 
     MoveData(Weak<dyn crate::static_data::MoveData>),
     Species(Weak<dyn crate::static_data::Species>),
@@ -182,13 +182,13 @@ impl FromWasmObj for crate::StringKey {
     }
 }
 
-impl From<&Arc<crate::static_data::EffectParameter>> for WasmObject {
-    fn from(value: &Arc<crate::static_data::EffectParameter>) -> Self {
+impl From<&Arc<crate::static_data::Parameter>> for WasmObject {
+    fn from(value: &Arc<crate::static_data::Parameter>) -> Self {
         Self::EffectParameter(Arc::downgrade(value))
     }
 }
 
-impl_from_wasm_obj!(EffectParameter, Arc<crate::static_data::EffectParameter>);
+impl_from_wasm_obj!(EffectParameter, Arc<crate::static_data::Parameter>);
 
 impl From<&Arc<dyn crate::static_data::MoveData>> for WasmObject {
     fn from(value: &Arc<dyn crate::static_data::MoveData>) -> Self {
diff --git a/src/script_implementations/wasm/item_script.rs b/src/script_implementations/wasm/item_script.rs
index 8bbcba4..737cd8f 100644
--- a/src/script_implementations/wasm/item_script.rs
+++ b/src/script_implementations/wasm/item_script.rs
@@ -2,7 +2,7 @@ use crate::dynamic_data::{ItemScript, Pokemon};
 use crate::script_implementations::wasm::export_registry::WasmVoidResultExtension;
 use crate::script_implementations::wasm::extern_ref::ExternRef;
 use crate::script_implementations::wasm::script_resolver::WebAssemblyEnvironmentData;
-use crate::static_data::EffectParameter;
+use crate::static_data::Parameter;
 use crate::StringKey;
 use std::sync::Arc;
 
@@ -64,12 +64,12 @@ macro_rules! ex_ref {
 }
 
 impl ItemScript for WebAssemblyItemScript {
-    fn on_initialize(&self, pars: Vec<Arc<EffectParameter>>) -> anyhow_ext::Result<()> {
+    fn on_initialize(&self, pars: Vec<Arc<Parameter>>) -> anyhow_ext::Result<()> {
         let env = &self.environment;
         if let Some(func) = env.script_function_cache().item_on_initialize(env) {
             let pars = pars
                 .into_iter()
-                .map(|p| ExternRef::<EffectParameter>::new(env, (&p).into()).index() as u32)
+                .map(|p| ExternRef::<Parameter>::new(env, (&p).into()).index() as u32)
                 .collect::<Vec<_>>();
             let wasm_ptr = env.copy_value_vec_to_wasm(&pars)?;
             let r: u64 = unsafe { std::mem::transmute((wasm_ptr, pars.len() as u32)) };
diff --git a/src/script_implementations/wasm/script.rs b/src/script_implementations/wasm/script.rs
index 4848750..04f1f96 100755
--- a/src/script_implementations/wasm/script.rs
+++ b/src/script_implementations/wasm/script.rs
@@ -12,7 +12,7 @@ use crate::script_implementations::wasm::export_registry::WasmVoidResultExtensio
 use crate::script_implementations::wasm::extern_ref::ExternRef;
 use crate::script_implementations::wasm::script_resolver::WebAssemblyEnvironmentData;
 use crate::script_implementations::wasm::WebAssemblyScriptCapabilities;
-use crate::static_data::{EffectParameter, Item, Statistic, TypeIdentifier};
+use crate::static_data::{Item, Parameter, Statistic, TypeIdentifier};
 use crate::StringKey;
 
 /// A WebAssemblyScript is there to implement the Script trait within WebAssemblyScript.
@@ -125,7 +125,7 @@ impl Script for WebAssemblyScript {
         Ok(())
     }
 
-    fn on_initialize(&self, library: &Arc<dyn DynamicLibrary>, pars: Vec<Arc<EffectParameter>>) -> Result<()> {
+    fn on_initialize(&self, library: &Arc<dyn DynamicLibrary>, pars: Vec<Arc<Parameter>>) -> Result<()> {
         if !self.has_capability(&WebAssemblyScriptCapabilities::Initialize) {
             return Ok(());
         }
@@ -134,7 +134,7 @@ impl Script for WebAssemblyScript {
         if let Some(func) = env.script_function_cache().on_initialize(env) {
             let pars = pars
                 .into_iter()
-                .map(|p| ExternRef::<EffectParameter>::new(env, (&p).into()).index() as u32)
+                .map(|p| ExternRef::<Parameter>::new(env, (&p).into()).index() as u32)
                 .collect::<Vec<_>>();
             let wasm_ptr = env.copy_value_vec_to_wasm(&pars)?;
             let r: u64 = unsafe { std::mem::transmute((wasm_ptr, pars.len() as u32)) };
diff --git a/src/static_data/libraries/species_library.rs b/src/static_data/libraries/species_library.rs
index d03bbe1..6f4f224 100755
--- a/src/static_data/libraries/species_library.rs
+++ b/src/static_data/libraries/species_library.rs
@@ -65,6 +65,7 @@ pub mod tests {
             0.5,
             &"test_growthrate".into(),
             0,
+            120,
             Arc::new(FormImpl::new(
                 &"default".into(),
                 0.0,
@@ -78,6 +79,7 @@ pub mod tests {
                 HashSet::new(),
             )),
             HashSet::new(),
+            Vec::new(),
         ))
     }
 
diff --git a/src/static_data/mod.rs b/src/static_data/mod.rs
index 777c76d..c413118 100755
--- a/src/static_data/mod.rs
+++ b/src/static_data/mod.rs
@@ -59,7 +59,7 @@ mod time_of_day;
 /// A parameter for an effect. This is basically a simple way to dynamically store multiple different
 /// primitives on data.
 #[derive(PartialEq, Debug, Clone)]
-pub enum EffectParameter {
+pub enum Parameter {
     /// A boolean value.
     Bool(bool),
     /// An integer value. Stored as a 64 bit int to deal with potentially large numbers.
@@ -70,37 +70,37 @@ pub enum EffectParameter {
     String(StringKey),
 }
 
-impl From<bool> for EffectParameter {
+impl From<bool> for Parameter {
     fn from(b: bool) -> Self {
-        EffectParameter::Bool(b)
+        Parameter::Bool(b)
     }
 }
 
-impl From<i64> for EffectParameter {
+impl From<i64> for Parameter {
     fn from(i: i64) -> Self {
-        EffectParameter::Int(i)
+        Parameter::Int(i)
     }
 }
 
-impl From<f32> for EffectParameter {
+impl From<f32> for Parameter {
     fn from(f: f32) -> Self {
-        EffectParameter::Float(f)
+        Parameter::Float(f)
     }
 }
 
-impl From<StringKey> for EffectParameter {
+impl From<StringKey> for Parameter {
     fn from(s: StringKey) -> Self {
-        EffectParameter::String(s)
+        Parameter::String(s)
     }
 }
 
-impl Display for EffectParameter {
+impl Display for Parameter {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         match self {
-            EffectParameter::Bool(v) => f.write_fmt(format_args!("EffectParameter::Bool({v})")),
-            EffectParameter::Int(v) => f.write_fmt(format_args!("EffectParameter::Int({v})")),
-            EffectParameter::Float(v) => f.write_fmt(format_args!("EffectParameter::Float({v})")),
-            EffectParameter::String(v) => f.write_fmt(format_args!("EffectParameter::String({v})")),
+            Parameter::Bool(v) => f.write_fmt(format_args!("EffectParameter::Bool({v})")),
+            Parameter::Int(v) => f.write_fmt(format_args!("EffectParameter::Int({v})")),
+            Parameter::Float(v) => f.write_fmt(format_args!("EffectParameter::Float({v})")),
+            Parameter::String(v) => f.write_fmt(format_args!("EffectParameter::String({v})")),
         }
     }
 }
diff --git a/src/static_data/moves/secondary_effect.rs b/src/static_data/moves/secondary_effect.rs
index 07fd518..42d7ed2 100755
--- a/src/static_data/moves/secondary_effect.rs
+++ b/src/static_data/moves/secondary_effect.rs
@@ -1,4 +1,4 @@
-use crate::static_data::EffectParameter;
+use crate::static_data::Parameter;
 use crate::StringKey;
 use std::fmt::Debug;
 use std::sync::Arc;
@@ -10,7 +10,7 @@ pub trait SecondaryEffect: Debug {
     /// The name of the effect.
     fn effect_name(&self) -> &StringKey;
     /// A list of parameters for the effect.
-    fn parameters(&self) -> &Vec<Arc<EffectParameter>>;
+    fn parameters(&self) -> &Vec<Arc<Parameter>>;
 }
 
 /// A secondary effect is an effect on a move that happens after it hits.
@@ -21,12 +21,12 @@ pub struct SecondaryEffectImpl {
     /// The name of the effect.
     effect_name: StringKey,
     /// A list of parameters for the effect.
-    parameters: Vec<Arc<EffectParameter>>,
+    parameters: Vec<Arc<Parameter>>,
 }
 
 impl SecondaryEffectImpl {
     /// Instantiates a new Secondary Effect.
-    pub fn new(chance: f32, effect_name: StringKey, parameters: Vec<Arc<EffectParameter>>) -> Self {
+    pub fn new(chance: f32, effect_name: StringKey, parameters: Vec<Arc<Parameter>>) -> Self {
         Self {
             chance,
             effect_name,
@@ -45,7 +45,7 @@ impl SecondaryEffect for SecondaryEffectImpl {
         &self.effect_name
     }
     /// A list of parameters for the effect.
-    fn parameters(&self) -> &Vec<Arc<EffectParameter>> {
+    fn parameters(&self) -> &Vec<Arc<Parameter>> {
         &self.parameters
     }
 }
@@ -66,7 +66,7 @@ pub(crate) mod tests {
         impl SecondaryEffect for SecondaryEffect {
             fn chance(&self) -> f32;
             fn effect_name(&self) -> &StringKey;
-            fn parameters(&self) -> &Vec<Arc<EffectParameter>>;
+            fn parameters(&self) -> &Vec<Arc<Parameter >>;
         }
     }
 
diff --git a/src/static_data/species_data/ability.rs b/src/static_data/species_data/ability.rs
index 15daa1a..721ed3e 100755
--- a/src/static_data/species_data/ability.rs
+++ b/src/static_data/species_data/ability.rs
@@ -1,4 +1,4 @@
-use crate::static_data::EffectParameter;
+use crate::static_data::Parameter;
 use crate::StringKey;
 use std::fmt::Debug;
 use std::sync::Arc;
@@ -10,7 +10,7 @@ pub trait Ability: Debug {
     /// The name of the script effect of the ability.
     fn effect(&self) -> &StringKey;
     /// The parameters for the script effect of the ability.
-    fn parameters(&self) -> &Vec<Arc<EffectParameter>>;
+    fn parameters(&self) -> &Vec<Arc<Parameter>>;
 }
 
 /// An ability is a passive effect in battle that is attached to a Pokemon.
@@ -21,12 +21,12 @@ pub struct AbilityImpl {
     /// The name of the script effect of the ability.
     effect: StringKey,
     /// The parameters for the script effect of the ability.
-    parameters: Vec<Arc<EffectParameter>>,
+    parameters: Vec<Arc<Parameter>>,
 }
 
 impl AbilityImpl {
     /// Instantiates a new ability.
-    pub fn new(name: &StringKey, effect: &StringKey, parameters: Vec<Arc<EffectParameter>>) -> Self {
+    pub fn new(name: &StringKey, effect: &StringKey, parameters: Vec<Arc<Parameter>>) -> Self {
         Self {
             name: name.clone(),
             effect: effect.clone(),
@@ -45,7 +45,7 @@ impl Ability for AbilityImpl {
         &self.effect
     }
     /// The parameters for the script effect of the ability.
-    fn parameters(&self) -> &Vec<Arc<EffectParameter>> {
+    fn parameters(&self) -> &Vec<Arc<Parameter>> {
         &self.parameters
     }
 }
@@ -74,7 +74,7 @@ pub(crate) mod tests {
         impl Ability for Ability {
             fn name(&self) -> &StringKey;
             fn effect(&self) -> &StringKey;
-            fn parameters(&self) -> &Vec<Arc<EffectParameter>>;
+            fn parameters(&self) -> &Vec<Arc<Parameter >>;
         }
     }
 }
diff --git a/src/static_data/species_data/evolution_data.rs b/src/static_data/species_data/evolution_data.rs
new file mode 100644
index 0000000..f9c39d7
--- /dev/null
+++ b/src/static_data/species_data/evolution_data.rs
@@ -0,0 +1,118 @@
+use crate::defines::LevelInt;
+use crate::static_data::{Gender, Parameter};
+use crate::StringKey;
+use std::sync::Arc;
+
+/// The different ways a Pokemon can evolve.
+#[derive(Debug)]
+pub enum EvolutionMethod {
+    /// Evolves when a certain level is reached.
+    Level {
+        /// The level at which the Pokemon evolves.
+        level: LevelInt,
+    },
+    /// Evolves when a certain level is reached, and the Pokemon is a specific gender.
+    LevelGender {
+        /// The level at which the Pokemon evolves.
+        level: LevelInt,
+        /// The gender the Pokemon needs to be.
+        gender: Gender,
+    },
+    /// Evolves when an item is used.
+    Item {
+        /// The item that needs to be used.
+        item: StringKey,
+    },
+    /// Evolves when an item is used, and the Pokemon is a specific gender.
+    ItemGender {
+        /// The item that needs to be used.
+        item: StringKey,
+        /// The gender the Pokemon needs to be.
+        gender: Gender,
+    },
+    /// Evolves if an item is held.
+    HoldItem {
+        /// The item that needs to be held.
+        item: StringKey,
+    },
+    /// Evolves if a held item is held, and it's day.
+    DayHoldItem {
+        /// The item that needs to be held.
+        item: StringKey,
+    },
+    /// Evolves if a held item is held, and it's night.
+    NightHoldItem {
+        /// The item that needs to be held.
+        item: StringKey,
+    },
+    /// Evolves if the Pokemon knows a certain move.
+    HasMove {
+        /// The move that needs to be known.
+        move_name: StringKey,
+    },
+    /// Evolves when above a certain happiness level.
+    Happiness {
+        /// The happiness level that needs to be reached.
+        happiness: u8,
+    },
+    /// Evolves when above a certain happiness level, and it's day.
+    HappinessDay {
+        /// The happiness level that needs to be reached.
+        happiness: u8,
+    },
+    /// Evolves when above a certain happiness level, and it's night.
+    HappinessNight {
+        /// The happiness level that needs to be reached.
+        happiness: u8,
+    },
+    /// Evolves when traded.
+    Trade,
+    /// Evolves when traded with a certain species.
+    TradeSpecies {
+        /// The species that needs to be traded with.
+        species: StringKey,
+    },
+    /// Evolves when traded while it's holding a certain item.
+    TradeItem {
+        /// The item that needs to be held.
+        item: StringKey,
+    },
+    /// Evolves in a certain location.
+    Location {
+        /// The location the Pokemon needs to be in.
+        location: StringKey,
+    },
+    /// A custom evolution method, implemented by the user.
+    Custom {
+        /// The name of the custom evolution method.
+        name: StringKey,
+        /// The parameters of the custom evolution method.
+        params: Vec<Arc<Parameter>>,
+    },
+}
+
+#[derive(Debug)]
+/// Data about how and into which Pokemon a species can evolve.
+pub struct EvolutionData {
+    /// The method of evolution.
+    method: EvolutionMethod,
+    /// The Pokemon the species evolves into.
+    to: StringKey,
+}
+
+impl EvolutionData {
+    /// Creates a new evolution data instance.
+    pub fn new(method: EvolutionMethod, to: StringKey) -> Self {
+        Self { method, to }
+    }
+
+    /// Returns the method of evolution.
+    pub fn method(&self) -> &EvolutionMethod {
+        &self.method
+    }
+
+    /// Returns the Pokemon the species evolves into.
+    pub fn to(&self) -> &StringKey {
+        &self.to
+    }
+}
diff --git a/src/static_data/species_data/mod.rs b/src/static_data/species_data/mod.rs
index b5254cc..53c33b9 100755
--- a/src/static_data/species_data/mod.rs
+++ b/src/static_data/species_data/mod.rs
@@ -1,6 +1,8 @@
 #[doc(inline)]
 pub use ability::*;
 #[doc(inline)]
+pub use evolution_data::*;
+#[doc(inline)]
 pub use form::*;
 #[doc(inline)]
 pub use gender::*;
@@ -19,6 +21,8 @@ pub(crate) mod tests {
 
 /// An ability is a passive effect in battle that is attached to a Pokemon.
 mod ability;
+/// Data regarding into which Pokemon a species can evolve.
+mod evolution_data;
 /// A form is a variant of a specific species. A species always has at least one form, but can have
 /// many more.
 mod form;
diff --git a/src/static_data/species_data/species.rs b/src/static_data/species_data/species.rs
index 5c0ba10..433cd24 100755
--- a/src/static_data/species_data/species.rs
+++ b/src/static_data/species_data/species.rs
@@ -6,6 +6,7 @@ use hashbrown::{HashMap, HashSet};
 use parking_lot::lock_api::RwLockReadGuard;
 use parking_lot::{RawRwLock, RwLock};
 
+use crate::static_data::species_data::evolution_data::EvolutionData;
 use crate::static_data::Form;
 use crate::static_data::Gender;
 use crate::Random;
@@ -24,6 +25,8 @@ pub trait Species: Debug {
     /// How hard it is to capture a Pokemon. 255 means this will be always caught, 0 means this is
     /// uncatchable.
     fn capture_rate(&self) -> u8;
+    /// The base happiness of the Pokemon.
+    fn base_happiness(&self) -> u8;
     /// The forms that belong to this Pokemon.
     fn forms(&self) -> RwLockReadGuard<'_, RawRwLock, HashMap<StringKey, Arc<dyn Form>>>;
     /// The arbitrary flags that can be set on a Pokemon for script use.
@@ -42,6 +45,8 @@ pub trait Species: Debug {
     fn has_flag(&self, key: &StringKey) -> bool;
     /// Check whether the Pokemon has a specific flag set.
     fn has_flag_by_hash(&self, key_hash: u32) -> bool;
+    /// The data regarding into which Pokemons this species can evolve, and how.
+    fn evolution_data(&self) -> &Vec<EvolutionData>;
 }
 
 /// The data belonging to a Pokemon with certain characteristics.
@@ -58,10 +63,14 @@ pub struct SpeciesImpl {
     /// How hard it is to capture a Pokemon. 255 means this will be always caught, 0 means this is
     /// uncatchable.
     capture_rate: u8,
+    /// The base happiness of the Pokemon.
+    base_happiness: u8,
     /// The forms that belong to this Pokemon.
     forms: RwLock<HashMap<StringKey, Arc<dyn Form>>>,
     /// The arbitrary flags that can be set on a Pokemon for script use.
     flags: HashSet<StringKey>,
+    /// The data regarding into which Pokemons this species can evolve, and how.
+    evolution_data: Vec<EvolutionData>,
 }
 
 /// A cached String Key to get the default form.
@@ -80,8 +89,10 @@ impl SpeciesImpl {
         gender_rate: f32,
         growth_rate: &StringKey,
         capture_rate: u8,
+        base_happiness: u8,
         default_form: Arc<dyn Form>,
         flags: HashSet<StringKey>,
+        evolution_data: Vec<EvolutionData>,
     ) -> Self {
         let mut forms = HashMap::with_capacity(1);
         forms.insert_unique_unchecked(get_default_key(), default_form);
@@ -91,8 +102,10 @@ impl SpeciesImpl {
             gender_rate,
             growth_rate: growth_rate.clone(),
             capture_rate,
+            base_happiness,
             forms: RwLock::new(forms),
             flags,
+            evolution_data,
         }
     }
 }
@@ -119,6 +132,11 @@ impl Species for SpeciesImpl {
     fn capture_rate(&self) -> u8 {
         self.capture_rate
     }
+
+    fn base_happiness(&self) -> u8 {
+        self.base_happiness
+    }
+
     /// The forms that belong to this Pokemon.
     fn forms(&self) -> RwLockReadGuard<'_, RawRwLock, HashMap<StringKey, Arc<dyn Form>>> {
         self.forms.read()
@@ -171,6 +189,10 @@ impl Species for SpeciesImpl {
     fn has_flag_by_hash(&self, key_hash: u32) -> bool {
         self.flags.contains::<u32>(&key_hash)
     }
+
+    fn evolution_data(&self) -> &Vec<EvolutionData> {
+        &self.evolution_data
+    }
 }
 
 #[cfg(test)]
@@ -188,6 +210,7 @@ pub(crate) mod tests {
             fn gender_rate(&self) -> f32;
             fn growth_rate(&self) -> &StringKey;
             fn capture_rate(&self) -> u8;
+            fn base_happiness(&self) -> u8;
             fn forms(&self) -> RwLockReadGuard<'_, RawRwLock, HashMap<StringKey, Arc<dyn Form>>>;
             fn flags(&self) -> &HashSet<StringKey>;
             fn add_form(&self, id: StringKey, form: Arc<dyn Form>);
@@ -197,6 +220,7 @@ pub(crate) mod tests {
             fn get_random_gender(&self, rand: &mut Random) -> Gender;
             fn has_flag(&self, key: &StringKey) -> bool;
             fn has_flag_by_hash(&self, key_hash: u32) -> bool;
+            fn evolution_data(&self) -> &Vec<EvolutionData>;
         }
     }
 }
diff --git a/tests/common/library_loader.rs b/tests/common/library_loader.rs
index 6aa0b35..881ba43 100755
--- a/tests/common/library_loader.rs
+++ b/tests/common/library_loader.rs
@@ -16,11 +16,12 @@ use pkmn_lib::dynamic_data::Gen7MiscLibrary;
 use pkmn_lib::dynamic_data::{DynamicLibrary, DynamicLibraryImpl};
 use pkmn_lib::dynamic_data::{Gen7BattleStatCalculator, ScriptResolver};
 use pkmn_lib::static_data::{
-    AbilityImpl, AbilityLibrary, AbilityLibraryImpl, BattleItemCategory, DataLibrary, EffectParameter, Form, FormImpl,
-    GrowthRateLibrary, GrowthRateLibraryImpl, ItemImpl, ItemLibrary, ItemLibraryImpl, LearnableMoves,
-    LearnableMovesImpl, LibrarySettingsImpl, LookupGrowthRate, MoveDataImpl, MoveLibrary, MoveLibraryImpl, NatureImpl,
-    NatureLibrary, NatureLibraryImpl, SecondaryEffect, SecondaryEffectImpl, SpeciesImpl, SpeciesLibrary,
-    SpeciesLibraryImpl, StaticDataImpl, StaticStatisticSet, Statistic, TimeOfDay, TypeLibrary, TypeLibraryImpl,
+    AbilityImpl, AbilityLibrary, AbilityLibraryImpl, BattleItemCategory, DataLibrary, EvolutionData, EvolutionMethod,
+    Form, FormImpl, Gender, GrowthRateLibrary, GrowthRateLibraryImpl, ItemImpl, ItemLibrary, ItemLibraryImpl,
+    LearnableMoves, LearnableMovesImpl, LibrarySettingsImpl, LookupGrowthRate, MoveDataImpl, MoveLibrary,
+    MoveLibraryImpl, NatureImpl, NatureLibrary, NatureLibraryImpl, Parameter, SecondaryEffect, SecondaryEffectImpl,
+    SpeciesImpl, SpeciesLibrary, SpeciesLibraryImpl, StaticDataImpl, StaticStatisticSet, Statistic, TimeOfDay,
+    TypeLibrary, TypeLibraryImpl,
 };
 use pkmn_lib::StringKey;
 
@@ -225,7 +226,7 @@ pub fn load_abilities(path: &String) -> Arc<dyn AbilityLibrary> {
         let mut parameters = Vec::new();
         if let Some(p) = value.get("parameters") {
             for par in p.as_array().unwrap() {
-                parameters.push(parse_effect_parameter(par));
+                parameters.push(parse_parameter(par));
             }
         }
 
@@ -261,7 +262,7 @@ pub fn load_moves(path: &String, types: &Arc<dyn TypeLibrary>) -> Arc<dyn MoveLi
             if let Some(pars) = v.get("parameters") {
                 let pars = pars.as_array().unwrap();
                 for par in pars {
-                    parameters.push(parse_effect_parameter(par));
+                    parameters.push(parse_parameter(par));
                 }
             }
 
@@ -321,7 +322,7 @@ pub fn load_species(
         let id = value.get("id").unwrap().as_i64().unwrap();
         let gender_rate = value.get("genderRatio").unwrap().as_f64().unwrap();
         let growth_rate_name = value.get("growthRate").unwrap().as_str().unwrap().into();
-        let _base_happiness = value.get("baseHappiness").unwrap().as_i64().unwrap();
+        let base_happiness = value.get("baseHappiness").unwrap().as_i64().unwrap();
         let catch_rate = value.get("catchRate").unwrap().as_i64().unwrap();
         let _color = value.get("color").unwrap().as_str().unwrap();
         // let egg_groups = value.get("eggGroups").unwrap()
@@ -332,7 +333,11 @@ pub fn load_species(
         //     .collect();
         let _egg_cycle = value.get("eggCycles").unwrap().as_i64().unwrap();
         // TODO: tags
-        // TODO: evolutions
+        let evolutions = if let Some(evolutions) = value.get("evolutions") {
+            evolutions.as_array().unwrap().iter().map(parse_evolution).collect()
+        } else {
+            Vec::new()
+        };
 
         let forms = value.get("formes").unwrap().as_object().unwrap();
         let default_form_value = forms.get("default").unwrap();
@@ -344,14 +349,108 @@ pub fn load_species(
             gender_rate as f32,
             &growth_rate_name,
             catch_rate as u8,
+            base_happiness as u8,
             default_form,
             Default::default(),
+            evolutions,
         );
         species_library.add(&name, Arc::new(species));
     }
     Arc::new(species_library)
 }
 
+fn parse_evolution(value: &Value) -> EvolutionData {
+    let species = StringKey::new(value.get("species").unwrap().as_str().unwrap());
+    let method = value.get("method").unwrap().as_str().unwrap();
+    let method = match method {
+        "level" => {
+            let level = value.get("data").unwrap().as_i64().unwrap() as LevelInt;
+            EvolutionMethod::Level { level }
+        }
+        "levelfemale" => {
+            let level = value.get("data").unwrap().as_i64().unwrap() as LevelInt;
+            EvolutionMethod::LevelGender {
+                level,
+                gender: Gender::Female,
+            }
+        }
+        "levelmale" => {
+            let level = value.get("data").unwrap().as_i64().unwrap() as LevelInt;
+            EvolutionMethod::LevelGender {
+                level,
+                gender: Gender::Male,
+            }
+        }
+        "happiness" => {
+            let happiness = value.get("data").unwrap().as_i64().unwrap() as u8;
+            EvolutionMethod::Happiness { happiness }
+        }
+        "happinessday" => {
+            let happiness = value.get("data").unwrap().as_i64().unwrap() as u8;
+            EvolutionMethod::HappinessDay { happiness }
+        }
+        "happinessnight" => {
+            let happiness = value.get("data").unwrap().as_i64().unwrap() as u8;
+            EvolutionMethod::HappinessNight { happiness }
+        }
+        "item" => {
+            let item = StringKey::new(value.get("data").unwrap().as_str().unwrap());
+            EvolutionMethod::Item { item }
+        }
+        "itemmale" => {
+            let item = StringKey::new(value.get("data").unwrap().as_str().unwrap());
+            EvolutionMethod::ItemGender {
+                item,
+                gender: Gender::Male,
+            }
+        }
+        "itemfemale" => {
+            let item = StringKey::new(value.get("data").unwrap().as_str().unwrap());
+            EvolutionMethod::ItemGender {
+                item,
+                gender: Gender::Female,
+            }
+        }
+        "holditem" => {
+            let item = StringKey::new(value.get("data").unwrap().as_str().unwrap());
+            EvolutionMethod::HoldItem { item }
+        }
+        "dayholditem" => {
+            let item = StringKey::new(value.get("data").unwrap().as_str().unwrap());
+            EvolutionMethod::DayHoldItem { item }
+        }
+        "nightholditem" => {
+            let item = StringKey::new(value.get("data").unwrap().as_str().unwrap());
+            EvolutionMethod::NightHoldItem { item }
+        }
+        "hasmove" => {
+            let move_name = StringKey::new(value.get("data").unwrap().as_str().unwrap());
+            EvolutionMethod::HasMove { move_name }
+        }
+        "trade" => EvolutionMethod::Trade,
+        "tradespecies" => {
+            let species = StringKey::new(value.get("data").unwrap().as_str().unwrap());
+            EvolutionMethod::TradeSpecies { species }
+        }
+        "tradeitem" => {
+            let item = StringKey::new(value.get("data").unwrap().as_str().unwrap());
+            EvolutionMethod::TradeItem { item }
+        }
+        "location" => {
+            let location = StringKey::new(value.get("data").unwrap().as_str().unwrap());
+            EvolutionMethod::Location { location }
+        }
+        "custom" => {
+            let data = value.get("data").unwrap().as_array().unwrap();
+            let name = StringKey::new(data[0].as_str().unwrap());
+            let params = data[1..].iter().map(parse_parameter).collect();
+            EvolutionMethod::Custom { name, params }
+        }
+        _ => panic!("Unknown evolution method: {}", method),
+    };
+    EvolutionData::new(method, species)
+}
+
 #[cfg(not(feature = "wasm"))]
 fn load_script_resolver(path: &String) -> Arc<dyn ScriptResolver> {
     Arc::new(EmptyScriptResolver::default())
@@ -471,7 +570,7 @@ fn parse_moves(value: &Value, move_library: &Arc<dyn MoveLibrary>) -> Arc<dyn Le
     Arc::new(moves)
 }
 
-fn parse_effect_parameter(value: &Value) -> Arc<EffectParameter> {
+fn parse_parameter(value: &Value) -> Arc<Parameter> {
     Arc::new(match value {
         Value::Null => {
             panic!("Unexpected type")
diff --git a/tests/data/Pokemon.json b/tests/data/Pokemon.json
index f549a2a..b072daa 100755
--- a/tests/data/Pokemon.json
+++ b/tests/data/Pokemon.json
@@ -8390,8 +8390,16 @@
       }
     },
     "evolutions": [
-      { "species": "wormadam", "method": "levelfemale", "data": "20" },
-      { "species": "mothim", "method": "levelmale", "data": "20" }
+      {
+        "species": "wormadam",
+        "method": "levelfemale",
+        "data": 20
+      },
+      {
+        "species": "mothim",
+        "method": "levelmale",
+        "data": 20
+      }
     ]
   },
   "butterfree": {
@@ -12710,7 +12718,11 @@
       }
     },
     "evolutions": [
-      { "species": "vespiquen", "method": "levelfemale", "data": "21" }
+      {
+        "species": "vespiquen",
+        "method": "levelfemale",
+        "data": 21
+      }
     ]
   },
   "combusken": {