use crate::config::{GameConfig, TileRegistry};
use crate::constants::ITILE_SIZE;
use crate::constants::TILE_SIZE;
use crate::constants::*;
use crate::entities::shared_components::Ambulatory;
use crate::game::SpawnDelay;
use crate::world::tiles::visibility::TileOcclusionEvent;
use crate::world::tiles::{FloorTileData, TileChangedEvent, TileMap};
use crate::world::VisibleGameEntity;
use bevy::prelude::*;
use bevy_rand::prelude::*;
use rand::RngExt;

/// How often (in seconds) a rabbit digs.
/// 5 seconds at normal speed — slow enough to observe, fast enough to test.
pub const DIG_INTERVAL_SECS: f32 = 5.0;

/// Temporary debug component. Attached to a rabbit for N ticks after it digs.
/// Removed automatically when tick_count reaches 0.
#[derive(Component)]
pub struct RabbitFallDebug {
    pub ticks_remaining: u8,
}

/// Tracks time until next dig action. Debug component — rabbits dig to demonstrate
/// the TileChangedEvent + path invalidation pipeline. Remove or replace when
/// real digging mechanics are implemented.
#[derive(Component)]
pub struct RabbitDigTimer {
    /// Seconds remaining until next dig. Reset to DIG_INTERVAL_SECS after each dig.
    pub secs_remaining: f32,
}

impl Default for RabbitDigTimer {
    fn default() -> Self {
        Self {
            secs_remaining: DIG_INTERVAL_SECS,
        }
    }
}

#[derive(Bundle)]
pub struct Rabbit {
    ambulatory: Ambulatory,
    sprite: Sprite,
    transform: Transform,
    visibility: Visibility,
    dig_timer: RabbitDigTimer,
}

impl Rabbit {
    pub fn new(asset_server: &Res<AssetServer>, position: Vec3) -> Self {
        Rabbit {
            ambulatory: Ambulatory {
                walk_speed: 1.,
                run_speed: 6.,
                target: None,
                current_path: None,
                path_index: 0,
                step_recovery: 0,
                validation_cooldown: 0,
                move_direction: Vec2::ZERO,
                step_history: [0i16; 4],
            },
            sprite: Sprite {
                image: asset_server.load("rabbit.png"),
                ..Default::default()
            },
            transform: Transform::from_translation(position).with_scale(Vec3::splat(PIXEL_RATIO)),
            visibility: Visibility::Hidden,
            dig_timer: RabbitDigTimer::default(),
        }
    }
}

pub fn spawn_rabbits(
    mut commands: Commands,
    asset_server: Res<AssetServer>,
    mut rng_q: Query<&mut WyRand, With<GlobalRng>>,
    config: Res<GameConfig>,
    mut delay: ResMut<SpawnDelay>,
    mut has_spawned: Local<bool>,
) {
    if *has_spawned {
        return;
    }

    if delay.0 < 60 {
        delay.0 += 1;
        return;
    }

    *has_spawned = true;

    if let Ok(mut rng) = rng_q.single_mut() {
        for _ in 0..config.spawn_counts.rabbits {
            let raw_x = rng.random_range(-32.0f32..32.0f32);
            let raw_y = rng.random_range(-32.0f32..32.0f32);
            let grid_x = (raw_x / TILE_SIZE).round() * TILE_SIZE;
            let grid_y = (raw_y / TILE_SIZE).round() * TILE_SIZE;
            let grid_z = 35.0 * TILE_SIZE;

            let rab = commands
                .spawn(Rabbit::new(
                    &asset_server,
                    Vec3::new(grid_x, grid_y, grid_z),
                ))
                .id();
            commands.entity(rab).insert(VisibleGameEntity);
        }
    }
}

/// Debug system: rabbits periodically dig the floor tile beneath them.
///
/// Removes the FloorTileData at the tile directly below the rabbit's current
/// z-level. Also clears the corresponding ChunkData bits via TileMap::remove_floor.
/// Fires TileChangedEvent so path invalidation reacts automatically.
pub fn rabbit_dig_system(
    mut commands: Commands,
    mut query: Query<(Entity, &Transform, &mut RabbitDigTimer)>,
    mut tilemap: ResMut<TileMap>,
    mut tile_changed: MessageWriter<TileChangedEvent>,
    mut occlusion: MessageWriter<TileOcclusionEvent>,
    time: Res<Time>,
) {
    for (entity, transform, mut dig_timer) in query.iter_mut() {
        if !tilemap.is_standable(transform.translation.as_ivec3()) {
            dig_timer.secs_remaining = DIG_INTERVAL_SECS;
            continue;
        }
        dig_timer.secs_remaining -= time.delta_secs();
        if dig_timer.secs_remaining > 0.0 {
            continue;
        }
        dig_timer.secs_remaining = DIG_INTERVAL_SECS;

        let entity_pos = transform.translation.as_ivec3();
        let below_pos = IVec3::new(entity_pos.x, entity_pos.y, entity_pos.z - ITILE_SIZE);

        // Don't dig below world floor — would panic in remove_floor bounds check.
        if below_pos.z < -(crate::world::chunks::Z_BELOW as i32 - 1) * ITILE_SIZE {
            continue;
        }

        // --- DEBUG: pre-dig state ---
        let (lx, ly, lz) =
            crate::world::tiles::ChunkData::world_to_local(transform.translation.as_ivec3());
        let chunk_pos = crate::world::chunks::world_to_chunk(transform.translation.as_ivec3());
        let standable_now = tilemap.is_standable(transform.translation.as_ivec3());
        println!(
            "[DIG PRE] entity={:?} world_pos=({:.1},{:.1},{:.1}) ivec={:?} \
             tile_local=({},{},{}) chunk={:?} standable={}",
            entity,
            transform.translation.x,
            transform.translation.y,
            transform.translation.z,
            entity_pos,
            lx,
            ly,
            lz,
            chunk_pos,
            standable_now
        );
        println!(
            "[DIG PRE] below_pos={:?} below_tile_z={}",
            below_pos,
            below_pos.z / ITILE_SIZE
        );

        let removed = tilemap.remove_floor(&below_pos);

        // Replace the dug tile with air. The slot must become passable — if the entry
        // is simply absent, ChunkData bits remain 0 (impassable), and is_standable
        // returns false. Air has can_stand_in=true so entities can fall through it.
        if removed.is_some() {
            let air = TileRegistry::global().floor("air");
            tilemap.insert_floor(
                below_pos,
                FloorTileData::new(
                    air.id,
                    air.can_stand_in,
                    air.can_stand_on,
                    air.transparent,
                    air.astar_weight,
                    [0; 8],
                ),
            );
        }
        println!(
            "[DIG] remove_floor({:?}) => {}",
            below_pos,
            if removed.is_some() {
                "REMOVED"
            } else {
                "NOT FOUND"
            }
        );

        // --- DEBUG: post-dig standability ---
        let standable_after = tilemap.is_standable(transform.translation.as_ivec3());
        println!(
            "[DIG POST] standable at entity pos after dig: {}",
            standable_after
        );

        if removed.is_some() {
            tile_changed.write(TileChangedEvent { pos: below_pos });

            // Refresh the full column below the dig and its XY neighbours.
            // calculate_visibility traces up to Z_TOTAL+Z_BELOW+1 tiles above each tile,
            // so removing one tile can affect visibility arbitrarily deep below.
            for dz in 0..=crate::world::chunks::Z_BELOW as i32 {
                for dy in -1..=1i32 {
                    for dx in -1..=1i32 {
                        occlusion.write(TileOcclusionEvent {
                            tile_position: below_pos
                                - IVec3::new(dx * ITILE_SIZE, dy * ITILE_SIZE, dz * ITILE_SIZE),
                        });
                    }
                }
            }
            // Attach fall debug component — tracks for 12 ticks
            commands.entity(entity).insert(RabbitFallDebug {
                ticks_remaining: 12,
            });
        }
    }
}

/// Temporary debug system. Prints rabbit position and standability for N ticks
/// after a dig event. Removes the RabbitFallDebug component when done.
pub fn rabbit_fall_debug_system(
    mut commands: Commands,
    mut query: Query<(Entity, &Transform, &mut RabbitFallDebug)>,
    tilemap: Res<TileMap>,
) {
    use crate::world::chunks::world_to_chunk;
    use crate::world::tiles::ChunkData;

    for (entity, transform, mut debug) in query.iter_mut() {
        let world_pos = transform.translation;
        let ivec = world_pos.as_ivec3();
        let (lx, ly, lz) = ChunkData::world_to_local(ivec);
        let lz_euclid = ivec.z.div_euclid(ITILE_SIZE); // compare truncation vs floor
        let chunk_pos = world_to_chunk(ivec);
        let standable = tilemap.is_standable(ivec);

        // Read ChunkData bits directly if chunk is loaded
        let (stand_in, stand_on_below) = if let Some(chunk) = tilemap.chunks.get(&chunk_pos) {
            let in_f = if lz >= -(crate::world::chunks::Z_BELOW as i32)
                && lz <= crate::world::chunks::Z_ABOVE as i32
                && lx >= 0
                && lx < crate::world::chunks::CHUNK_SIZE
                && ly >= 0
                && ly < crate::world::chunks::CHUNK_SIZE
            {
                let idx = ChunkData::pos_to_index(lx, ly, lz);
                let word = idx / 32;
                let mask = 1u32 << (idx % 32);
                let in_floor = (chunk.stand_in_floor[word] & mask) != 0;
                let in_fix = (chunk.stand_in_fixture[word] & mask) != 0;
                format!("in_floor={} in_fixture={}", in_floor, in_fix)
            } else {
                format!("OUT_OF_BOUNDS(lz={})", lz)
            };

            let on_f = if lz - 1 >= -(crate::world::chunks::Z_BELOW as i32)
                && lz - 1 <= crate::world::chunks::Z_ABOVE as i32
                && lx >= 0
                && lx < crate::world::chunks::CHUNK_SIZE
                && ly >= 0
                && ly < crate::world::chunks::CHUNK_SIZE
            {
                let idx = ChunkData::pos_to_index(lx, ly, lz - 1);
                let word = idx / 32;
                let mask = 1u32 << (idx % 32);
                let on_floor = (chunk.stand_on_floor[word] & mask) != 0;
                let on_fix = (chunk.stand_on_fixture[word] & mask) != 0;
                format!("on_floor[z-1]={} on_fixture[z-1]={}", on_floor, on_fix)
            } else {
                "BELOW_BOUNDS".to_string()
            };

            (in_f, on_f)
        } else {
            (
                "chunk_not_loaded".to_string(),
                "chunk_not_loaded".to_string(),
            )
        };

        println!(
            "[FALL {:2}] entity={:?} world_z={:.1} ivec_z={} lz_trunc={} lz_euclid={} \
             standable={} | {} | {}",
            debug.ticks_remaining,
            entity,
            world_pos.z,
            ivec.z,
            lz,
            lz_euclid,
            standable,
            stand_in,
            stand_on_below
        );

        debug.ticks_remaining -= 1;
        if debug.ticks_remaining == 0 {
            commands.entity(entity).remove::<RabbitFallDebug>();
        }
    }
}