use std::ops::Deref;
use std::sync::Arc;

use num_traits::abs;

use crate::dynamic_data::Battle;
use crate::dynamic_data::Pokemon;
use crate::static_data::MoveTarget;

/// Helper type for the vector of targets we will return.
pub type TargetList = Vec<Option<Arc<Pokemon>>>;

/// This returns all Pokemon in the battle.
fn get_all_targets(battle: &Battle) -> TargetList {
    let mut v = Vec::with_capacity(battle.pokemon_per_side() as usize * battle.number_of_sides() as usize);
    for side in battle.sides() {
        for pokemon in side.pokemon().deref() {
            v.push(pokemon.as_ref().cloned());
        }
    }
    v
}

/// Little helper function to get the other side. 1 --> 0, 0 --> 1
fn get_opposite_side(side: u8) -> u8 {
    if side == 0 {
        return 1;
    }
    0
}

/// Gets all Pokemon that are adjacent to of directly opposite of a Pokemon. This means the target,
/// the Pokemon left of it, the Pokemon right of it, and the Pokemon opposite of it.
fn get_all_adjacent_opponent(side: u8, index: u8, battle: &Battle) -> TargetList {
    let left = index as i32 - 1;
    let right = index + 1;
    if left < 0 && right >= battle.pokemon_per_side() {
        return vec![
            battle.get_pokemon(side, index).as_ref().cloned(),
            battle.get_pokemon(get_opposite_side(side), index).as_ref().cloned(),
        ];
    }
    if left >= 0 {
        return if right < battle.pokemon_per_side() {
            vec![
                battle.get_pokemon(side, index).as_ref().cloned(),
                battle.get_pokemon(side, left as u8).as_ref().cloned(),
                battle.get_pokemon(side, right).as_ref().cloned(),
                battle
                    .get_pokemon(get_opposite_side(side), left as u8)
                    .as_ref()
                    .cloned(),
                battle.get_pokemon(get_opposite_side(side), index).as_ref().cloned(),
                battle.get_pokemon(get_opposite_side(side), right).as_ref().cloned(),
            ]
        } else {
            vec![
                battle.get_pokemon(side, index).as_ref().cloned(),
                battle.get_pokemon(side, left as u8).as_ref().cloned(),
                battle.get_pokemon(get_opposite_side(side), index).as_ref().cloned(),
                battle
                    .get_pokemon(get_opposite_side(side), left as u8)
                    .as_ref()
                    .cloned(),
            ]
        };
    }

    vec![
        battle.get_pokemon(side, index).as_ref().cloned(),
        battle.get_pokemon(side, right).as_ref().cloned(),
        battle.get_pokemon(get_opposite_side(side), index).as_ref().cloned(),
        battle.get_pokemon(get_opposite_side(side), right).as_ref().cloned(),
    ]
}

/// Gets all Pokemon that are adjacent to a Pokemon. This includes the target, the Pokemon to the
/// left of it, and the Pokemon to the right of it.
fn get_all_adjacent(side: u8, index: u8, battle: &Battle) -> TargetList {
    let left = index as i32 - 1;
    let right = index + 1;
    if left < 0 && right >= battle.pokemon_per_side() {
        return vec![battle.get_pokemon(side, index).as_ref().cloned()];
    }
    if left >= 0 {
        if right < battle.pokemon_per_side() {
            return vec![
                battle.get_pokemon(side, index).as_ref().cloned(),
                battle.get_pokemon(side, left as u8).as_ref().cloned(),
                battle.get_pokemon(side, right).as_ref().cloned(),
            ];
        }
        return vec![
            battle.get_pokemon(side, index).as_ref().cloned(),
            battle.get_pokemon(side, left as u8).as_ref().cloned(),
        ];
    }
    vec![
        battle.get_pokemon(side, index).as_ref().cloned(),
        battle.get_pokemon(side, right).as_ref().cloned(),
    ]
}

/// Gets the target for a specific move target type, given the targeted position.
pub fn resolve_targets(side: u8, index: u8, target: MoveTarget, battle: &Battle) -> TargetList {
    match target {
        // These all resolve to a single position. We let the client deal with where the target is,
        // and just return the Pokemon at that given target here.
        MoveTarget::Adjacent
        | MoveTarget::AdjacentAlly
        | MoveTarget::AdjacentAllySelf
        | MoveTarget::AdjacentOpponent
        | MoveTarget::Any
        | MoveTarget::RandomOpponent
        | MoveTarget::SelfUse => {
            vec![battle.get_pokemon(side, index).as_ref().cloned()]
        }
        // If all pokemon are requested, give all Pokemon on the battlefield
        MoveTarget::All => get_all_targets(battle),
        // If the adjacent Pokemon are requested, pass those.
        MoveTarget::AllAdjacent => get_all_adjacent(side, index, battle),
        // If the adjacent and opponent Pokemon are requested, give those.
        MoveTarget::AllAdjacentOpponent => get_all_adjacent_opponent(side, index, battle),
        // If all Pokemon on a side are requested, simply give all Pokemon on the side back, and let
        // the client deal with what side is passed.
        MoveTarget::AllAlly | MoveTarget::AllOpponent => {
            let mut v = Vec::new();
            for pokemon in battle.sides()[side as usize].pokemon().deref() {
                v.push(pokemon.as_ref().cloned());
            }
            v
        }
    }
}

/// Checks whether a given side and index are valid for a given move target and user.
pub fn is_valid_target(side: u8, index: u8, target: MoveTarget, user: &Pokemon) -> bool {
    let user_side = user.get_battle_side_index();
    let user_index = user.get_battle_index();
    // If the user is not on the field, nothing is a valid target
    if user_side.is_none() || user_index.is_none() {
        return false;
    }

    match target {
        MoveTarget::Adjacent | MoveTarget::AllAdjacent => {
            let diff = abs(index as i32 - user_index.unwrap() as i32);
            if diff == 0 {
                return user_side.unwrap() != side;
            }
            diff <= 1
        }
        MoveTarget::AdjacentAlly => {
            if user_side.unwrap() != side {
                false
            } else {
                abs(index as i32 - user_index.unwrap() as i32) == 1
            }
        }
        MoveTarget::AdjacentAllySelf => {
            if user_side.unwrap() != side {
                false
            } else {
                abs(index as i32 - user_index.unwrap() as i32) <= 1
            }
        }
        MoveTarget::AdjacentOpponent | MoveTarget::AllAdjacentOpponent => {
            if user_side.unwrap() == side {
                false
            } else {
                abs(index as i32 - user_index.unwrap() as i32) <= 1
            }
        }
        MoveTarget::All | MoveTarget::Any | MoveTarget::RandomOpponent => true,
        MoveTarget::AllAlly => user_side.unwrap() == side,
        MoveTarget::AllOpponent => user_side.unwrap() != side,
        MoveTarget::SelfUse => user_side.unwrap() == side && user_index.unwrap() == index,
    }
}