use std::fmt::Debug;
use std::sync::{Arc, LazyLock};

use hashbrown::{HashMap, HashSet};
use parking_lot::lock_api::RwLockReadGuard;
use parking_lot::{RawRwLock, RwLock};

use crate::static_data::Form;
use crate::static_data::Gender;
use crate::StringKey;
use crate::{Random, ValueIdentifiable, ValueIdentifier};

/// The data belonging to a Pokemon with certain characteristics.
pub trait Species: ValueIdentifiable + Debug {
    /// The national dex identifier of the Pokemon.
    fn id(&self) -> u16;
    /// The name of the Pokemon.
    fn name(&self) -> &StringKey;
    /// The chance between 0.0 and 1.0 that a Pokemon is female.
    fn gender_rate(&self) -> f32;
    /// How much experience is required for a level.
    fn growth_rate(&self) -> &StringKey;
    /// 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 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.
    fn flags(&self) -> &HashSet<StringKey>;
    /// Adds a new form to the species.
    fn add_form(&self, id: StringKey, form: Arc<dyn Form>);
    /// Gets a form by name.
    fn get_form(&self, id: &StringKey) -> Option<Arc<dyn Form>>;
    /// Gets the form the Pokemon will have by default, if no other form is specified.
    fn get_default_form(&self) -> Arc<dyn Form>;
    /// Gets a random gender.
    fn get_random_gender(&self, rand: &mut Random) -> Gender;
    /// Check whether the Pokemon has a specific flag set.
    fn has_flag(&self, key: &StringKey) -> bool;
}

/// The data belonging to a Pokemon with certain characteristics.
#[derive(Debug)]
pub struct SpeciesImpl {
    /// A unique identifier so we know what value this is.
    identifier: ValueIdentifier,
    /// The national dex identifier of the Pokemon.
    id: u16,
    /// The name of the Pokemon.
    name: StringKey,
    /// The chance between 0.0 and 1.0 that a Pokemon is female.
    gender_rate: f32,
    /// How much experience is required for a level.
    growth_rate: StringKey,
    /// How hard it is to capture a Pokemon. 255 means this will be always caught, 0 means this is
    /// uncatchable.
    capture_rate: 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>,
}

/// A cached String Key to get the default form.
static DEFAULT_KEY: LazyLock<StringKey> = LazyLock::new(|| StringKey::new("default"));

/// Gets the StringKey for "default". Initialises it if it does not exist.
fn get_default_key() -> StringKey {
    DEFAULT_KEY.clone()
}

impl SpeciesImpl {
    /// Creates a new species.
    pub fn new(
        id: u16,
        name: &StringKey,
        gender_rate: f32,
        growth_rate: &StringKey,
        capture_rate: u8,
        default_form: Arc<dyn Form>,
        flags: HashSet<StringKey>,
    ) -> Self {
        let mut forms = HashMap::with_capacity(1);
        forms.insert_unique_unchecked(get_default_key(), default_form);
        Self {
            identifier: Default::default(),
            id,
            name: name.clone(),
            gender_rate,
            growth_rate: growth_rate.clone(),
            capture_rate,
            forms: RwLock::new(forms),
            flags,
        }
    }
}

impl Species for SpeciesImpl {
    /// The national dex identifier of the Pokemon.
    fn id(&self) -> u16 {
        self.id
    }
    /// The name of the Pokemon.
    fn name(&self) -> &StringKey {
        &self.name
    }
    /// The chance between 0.0 and 1.0 that a Pokemon is female.
    fn gender_rate(&self) -> f32 {
        self.gender_rate
    }
    /// How much experience is required for a level.
    fn growth_rate(&self) -> &StringKey {
        &self.growth_rate
    }
    /// 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 {
        self.capture_rate
    }
    /// The forms that belong to this Pokemon.
    fn forms(&self) -> RwLockReadGuard<'_, RawRwLock, HashMap<StringKey, Arc<dyn Form>>> {
        self.forms.read()
    }
    /// The arbitrary flags that can be set on a Pokemon for script use.
    fn flags(&self) -> &HashSet<StringKey> {
        &self.flags
    }

    /// Adds a new form to the species.
    fn add_form(&self, id: StringKey, form: Arc<dyn Form>) {
        self.forms.write().insert(id, form);
    }

    /// Gets a form by name.
    fn get_form(&self, id: &StringKey) -> Option<Arc<dyn Form>> {
        self.forms.read().get(id).cloned()
    }

    /// Gets the form the Pokemon will have by default, if no other form is specified.
    fn get_default_form(&self) -> Arc<dyn Form> {
        self.forms.read().get(&get_default_key()).unwrap().clone()
    }

    /// Gets a random gender.
    fn get_random_gender(&self, rand: &mut Random) -> Gender {
        if self.gender_rate < 0.0 {
            Gender::Genderless
        } else if rand.get_float() >= self.gender_rate {
            Gender::Female
        } else {
            Gender::Male
        }
    }

    /// Check whether the Pokemon has a specific flag set.
    fn has_flag(&self, key: &StringKey) -> bool {
        self.flags.contains(key)
    }
}

impl ValueIdentifiable for SpeciesImpl {
    fn value_identifier(&self) -> ValueIdentifier {
        self.identifier
    }
}

#[cfg(test)]
pub(crate) mod tests {
    use super::*;

    mockall::mock! {
        #[derive(Debug)]
        pub Species {}
        impl Species for Species {
            fn id(&self) -> u16;
            fn name(&self) -> &StringKey;
            fn gender_rate(&self) -> f32;
            fn growth_rate(&self) -> &StringKey;
            fn capture_rate(&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>);
            fn get_form(&self, id: &StringKey) -> Option<Arc<dyn Form>>;
            fn get_default_form(&self) -> Arc<dyn Form>;
            fn get_random_gender(&self, rand: &mut Random) -> Gender;
            fn has_flag(&self, key: &StringKey) -> bool;
        }
        impl ValueIdentifiable for Species {
            fn value_identifier(&self) -> ValueIdentifier {
                ValueIdentifier::new(0)
            }
        }
    }
}