use bevy::prelude::*;

use crate::{
    camera::MatchCamera,
    fighter::{
        FighterECB, FighterFacingDirection, FighterHitboxes, FighterHitstop,
        FighterPreviousFacingDirection, FighterPreviousTranslation, FighterTranslation,
        FighterVelocity, Grounded,
        animation::FighterAnimationFrame,
        attack::{
            FighterDamage, FighterKnockbackVelocity, FighterPendingHitReaction, FighterPendingHits,
            FighterSolvedHurtboxes, FighterStaleMoveQueue,
        },
        baked_animation::FighterBoneMatrices,
        state::FighterState,
    },
    input::FighterInput,
    player::Player,
    stage::line::StageCollision,
};

#[derive(Resource, Default)]
pub(super) struct DebugSaveState {
    checkpoint: Option<Checkpoint>,
}

#[derive(Clone)]
struct Checkpoint {
    fighters: Vec<FighterCheckpoint>,
    stage_collision: StageCollision,
    pending_hits: FighterPendingHits,
}

#[derive(Clone)]
struct FighterCheckpoint {
    entity: Entity,
    handle: usize,
    ecb: FighterECB,
    previous_ecb: crate::fighter::ecb::FighterPreviousECB,
    velocity: FighterVelocity,
    translation: FighterTranslation,
    previous_translation: FighterPreviousTranslation,
    facing: FighterFacingDirection,
    previous_facing: FighterPreviousFacingDirection,
    animation: FighterAnimationFrame,
    state: FighterState,
    input: FighterInput,
    damage: FighterDamage,
    pending_hit_reaction: FighterPendingHitReaction,
    hitstop: FighterHitstop,
    knockback_velocity: FighterKnockbackVelocity,
    stale_moves: FighterStaleMoveQueue,
    hitboxes: FighterHitboxes,
    solved_hurtboxes: FighterSolvedHurtboxes,
    bone_matrices: FighterBoneMatrices,
    grounded: bool,
}

pub(super) fn save_or_restore(world: &mut World) {
    if world.resource::<super::DebugSettings>().menu_open {
        return;
    }

    let left = world
        .query::<&Gamepad>()
        .iter(world)
        .any(|gamepad| gamepad.just_pressed(GamepadButton::DPadLeft));
    let right = world
        .query::<&Gamepad>()
        .iter(world)
        .any(|gamepad| gamepad.just_pressed(GamepadButton::DPadRight));

    if left == right {
        return;
    }

    let Some(roster) = world
        .get_resource::<crate::fighter::FighterRoster>()
        .map(|roster| roster.0.clone())
    else {
        return;
    };
    if roster.len() != 1 {
        warn!("Save states are only available in single-player matches");
        return;
    }

    if left {
        let Some(stage_collision) = world.get_resource::<StageCollision>().cloned() else {
            return;
        };
        let mut checkpoint_fighters = Vec::with_capacity(roster.len());
        for entity in roster.iter().copied() {
            let Some(checkpoint) = capture_fighter(world, entity) else {
                warn!("Could not save the current fighter state");
                return;
            };
            checkpoint_fighters.push(checkpoint);
        }
        let pending_hits = world.resource::<FighterPendingHits>().clone();
        world.resource_mut::<DebugSaveState>().checkpoint = Some(Checkpoint {
            fighters: checkpoint_fighters,
            stage_collision,
            pending_hits,
        });
        info!("Saved debug game state");
        return;
    }

    let Some(checkpoint) = world.resource::<DebugSaveState>().checkpoint.clone() else {
        warn!("No debug game state has been saved");
        return;
    };
    if checkpoint.fighters.len() != roster.len()
        || checkpoint
            .fighters
            .iter()
            .zip(roster.iter())
            .any(|(saved, current)| saved.entity != *current)
    {
        warn!("Saved debug game state belongs to another match");
        return;
    }

    for saved in &checkpoint.fighters {
        let Some(player) = world.entity(saved.entity).get::<Player>() else {
            warn!("Could not restore the saved fighter state");
            return;
        };
        if player.handle != saved.handle {
            warn!("Saved debug game state belongs to another match");
            return;
        }

        let mut entity = world.entity_mut(saved.entity);
        entity.insert(saved.ecb);
        entity.insert(saved.previous_ecb);
        entity.insert(saved.velocity);
        entity.insert(saved.translation);
        entity.insert(saved.previous_translation);
        entity.insert(saved.facing);
        entity.insert(saved.previous_facing);
        entity.insert(saved.animation);
        entity.insert(saved.state.clone());
        entity.insert(saved.input);
        entity.insert(saved.damage);
        entity.insert(saved.pending_hit_reaction.clone());
        entity.insert(saved.hitstop);
        entity.insert(saved.knockback_velocity);
        entity.insert(saved.stale_moves.clone());
        entity.insert(saved.hitboxes.clone());
        entity.insert(saved.solved_hurtboxes.clone());
        entity.insert(saved.bone_matrices.clone());
        if saved.grounded {
            entity.insert(Grounded);
        } else {
            entity.remove::<Grounded>();
        }
    }
    world.insert_resource(checkpoint.pending_hits.clone());
    world.insert_resource(checkpoint.stage_collision);
    for mut match_camera in world.query::<&mut MatchCamera>().iter_mut(world) {
        match_camera.needs_snap = true;
    }
    info!("Restored debug game state");
}

fn capture_fighter(world: &World, entity: Entity) -> Option<FighterCheckpoint> {
    let fighter = world.entity(entity);
    Some(FighterCheckpoint {
        entity,
        handle: fighter.get::<Player>()?.handle,
        ecb: *fighter.get::<FighterECB>()?,
        previous_ecb: *fighter.get::<crate::fighter::ecb::FighterPreviousECB>()?,
        velocity: *fighter.get::<FighterVelocity>()?,
        translation: *fighter.get::<FighterTranslation>()?,
        previous_translation: *fighter.get::<FighterPreviousTranslation>()?,
        facing: *fighter.get::<FighterFacingDirection>()?,
        previous_facing: *fighter.get::<FighterPreviousFacingDirection>()?,
        animation: *fighter.get::<FighterAnimationFrame>()?,
        state: fighter.get::<FighterState>()?.clone(),
        input: *fighter.get::<FighterInput>()?,
        damage: *fighter.get::<FighterDamage>()?,
        pending_hit_reaction: fighter.get::<FighterPendingHitReaction>()?.clone(),
        hitstop: *fighter.get::<FighterHitstop>()?,
        knockback_velocity: *fighter.get::<FighterKnockbackVelocity>()?,
        stale_moves: fighter.get::<FighterStaleMoveQueue>()?.clone(),
        hitboxes: fighter.get::<FighterHitboxes>()?.clone(),
        solved_hurtboxes: fighter.get::<FighterSolvedHurtboxes>()?.clone(),
        bone_matrices: fighter.get::<FighterBoneMatrices>()?.clone(),
        grounded: fighter.contains::<Grounded>(),
    })
}

pub(super) fn clear(mut save_state: ResMut<DebugSaveState>) {
    save_state.checkpoint = None;
}