#![allow(clippy::collapsible_if)]
use crate::memory_banks::{SoundBankPoolInstaller, TileBankPoolInstaller};
use prometeu_hal::AssetBridge;
use prometeu_hal::asset::{
    AssetEntry, AssetId, AssetLoadError, AssetOpStatus, BankStats, BankType, HandleId, LoadStatus,
    PreloadEntry, SlotRef, SlotStats,
};
use prometeu_hal::cartridge::AssetsPayloadSource;
use prometeu_hal::color::Color;
use prometeu_hal::sample::Sample;
use prometeu_hal::sound_bank::SoundBank;
use prometeu_hal::tile_bank::{TileBank, TileSize};
use std::collections::HashMap;
use std::io::Read;
use std::sync::{Arc, Mutex, RwLock};
use std::thread;
use std::time::Instant;

const TILE_BANK_PALETTE_COUNT_V1: usize = 64;
const TILE_BANK_COLORS_PER_PALETTE: usize = 16;
const TILE_BANK_PALETTE_BYTES_V1: usize =
    TILE_BANK_PALETTE_COUNT_V1 * TILE_BANK_COLORS_PER_PALETTE * std::mem::size_of::<u16>();

/// Resident metadata for a decoded/materialized asset inside a BankPolicy.
#[derive(Debug)]
pub struct ResidentEntry<T> {
    /// The resident, materialized object.
    pub value: Arc<T>,

    /// Resident size in bytes (post-decode). Used for telemetry/budgets.
    pub bytes: usize,

    // /// Pin count (optional): if > 0, entry should not be evicted by policy.
    // pub pins: u32,
    /// Telemetry / profiling fields (optional but useful).
    pub loads: u64,
    pub last_used: Instant,
}

impl<T> ResidentEntry<T> {
    pub fn new(value: Arc<T>, bytes: usize) -> Self {
        Self {
            value,
            bytes,
            // pins: 0,
            loads: 1,
            last_used: Instant::now(),
        }
    }
}

/// Encapsulates the residency and staging policy for a specific type of asset.
/// This is internal to the AssetManager and not visible to peripherals.
pub struct BankPolicy<T> {
    /// Dedup table: asset_id -> resident entry (value + telemetry).
    resident: Arc<RwLock<HashMap<AssetId, ResidentEntry<T>>>>,

    /// Staging area: handle -> value ready to commit.
    staging: Arc<RwLock<HashMap<HandleId, Arc<T>>>>,
}

impl<T> BankPolicy<T> {
    pub fn new() -> Self {
        Self {
            resident: Arc::new(RwLock::new(HashMap::new())),
            staging: Arc::new(RwLock::new(HashMap::new())),
        }
    }

    /// Try get a resident value by asset_id (dedupe path).
    pub fn get_resident(&self, asset_id: AssetId) -> Option<Arc<T>> {
        let mut map = self.resident.write().unwrap();
        let entry = map.get_mut(&asset_id)?;
        entry.last_used = Instant::now();
        Some(Arc::clone(&entry.value))
    }

    /// Insert or reuse a resident entry. Returns the resident Arc<T>.
    pub fn put_resident(&self, asset_id: AssetId, value: Arc<T>, bytes: usize) -> Arc<T> {
        let mut map = self.resident.write().unwrap();
        match map.get_mut(&asset_id) {
            Some(existing) => {
                existing.last_used = Instant::now();
                existing.loads += 1;
                Arc::clone(&existing.value)
            }
            None => {
                let entry = ResidentEntry::new(Arc::clone(&value), bytes);
                map.insert(asset_id, entry);
                value
            }
        }
    }

    /// Place a value into staging for a given handle.
    pub fn stage(&self, handle: HandleId, value: Arc<T>) {
        self.staging.write().unwrap().insert(handle, value);
    }

    /// Take staged value (used by commit path).
    pub fn take_staging(&self, handle: HandleId) -> Option<Arc<T>> {
        self.staging.write().unwrap().remove(&handle)
    }

    pub fn clear(&self) {
        self.resident.write().unwrap().clear();
        self.staging.write().unwrap().clear();
    }
}

pub struct AssetManager {
    assets: Arc<RwLock<HashMap<AssetId, AssetEntry>>>,
    handles: Arc<RwLock<HashMap<HandleId, LoadHandleInfo>>>,
    next_handle_id: Mutex<HandleId>,
    assets_data: Arc<RwLock<AssetsPayloadSource>>,

    /// Narrow hardware interfaces
    gfx_installer: Arc<dyn TileBankPoolInstaller>,
    sound_installer: Arc<dyn SoundBankPoolInstaller>,

    /// Track what is installed in each hardware slot (for stats/info).
    gfx_slots: Arc<RwLock<[Option<AssetId>; 16]>>,
    sound_slots: Arc<RwLock<[Option<AssetId>; 16]>>,

    /// Residency policy for GFX tile banks.
    gfx_policy: BankPolicy<TileBank>,
    /// Residency policy for sound banks.
    sound_policy: BankPolicy<SoundBank>,

    // Commits that are ready to be applied at the next frame boundary.
    pending_commits: Mutex<Vec<HandleId>>,
}

struct LoadHandleInfo {
    _asset_id: AssetId,
    slot: SlotRef,
    status: LoadStatus,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum AssetOpMode {
    DirectFromSlice,
    StageInMemory,
}

impl AssetBridge for AssetManager {
    fn initialize_for_cartridge(
        &self,
        assets: Vec<AssetEntry>,
        preload: Vec<PreloadEntry>,
        assets_data: AssetsPayloadSource,
    ) {
        self.initialize_for_cartridge(assets, preload, assets_data)
    }
    fn load(&self, asset_id: AssetId, slot_index: usize) -> Result<HandleId, AssetLoadError> {
        self.load(asset_id, slot_index)
    }
    fn status(&self, handle: HandleId) -> LoadStatus {
        self.status(handle)
    }
    fn commit(&self, handle: HandleId) -> AssetOpStatus {
        self.commit(handle)
    }
    fn cancel(&self, handle: HandleId) -> AssetOpStatus {
        self.cancel(handle)
    }
    fn apply_commits(&self) {
        self.apply_commits()
    }
    fn bank_info(&self, kind: BankType) -> BankStats {
        self.bank_info(kind)
    }
    fn slot_info(&self, slot: SlotRef) -> SlotStats {
        self.slot_info(slot)
    }
    fn shutdown(&self) {
        self.shutdown()
    }
}

impl AssetManager {
    fn codec_is_none_or_legacy_raw(codec: &str) -> bool {
        matches!(codec, "NONE" | "RAW")
    }

    fn decode_tile_bank_layout(
        entry: &AssetEntry,
    ) -> Result<(TileSize, usize, usize, usize), String> {
        let tile_size_val =
            entry.metadata.get("tile_size").and_then(|v| v.as_u64()).ok_or("Missing tile_size")?;
        let width =
            entry.metadata.get("width").and_then(|v| v.as_u64()).ok_or("Missing width")? as usize;
        let height =
            entry.metadata.get("height").and_then(|v| v.as_u64()).ok_or("Missing height")? as usize;
        let palette_count = entry
            .metadata
            .get("palette_count")
            .and_then(|v| v.as_u64())
            .ok_or("Missing palette_count")? as usize;

        let tile_size = match tile_size_val {
            8 => TileSize::Size8,
            16 => TileSize::Size16,
            32 => TileSize::Size32,
            _ => return Err(format!("Invalid tile_size: {}", tile_size_val)),
        };

        if palette_count != TILE_BANK_PALETTE_COUNT_V1 {
            return Err(format!("Invalid palette_count: {}", palette_count));
        }

        let logical_pixels = width.checked_mul(height).ok_or("TileBank dimensions overflow")?;
        let serialized_pixel_bytes = logical_pixels.div_ceil(2);
        let serialized_size = serialized_pixel_bytes
            .checked_add(TILE_BANK_PALETTE_BYTES_V1)
            .ok_or("TileBank serialized size overflow")?;
        let decoded_size = logical_pixels
            .checked_add(TILE_BANK_PALETTE_BYTES_V1)
            .ok_or("TileBank decoded size overflow")?;

        if entry.size != serialized_size as u64 {
            return Err(format!(
                "Invalid TILEBANK serialized size: expected {}, got {}",
                serialized_size, entry.size
            ));
        }

        if entry.decoded_size != decoded_size as u64 {
            return Err(format!(
                "Invalid TILEBANK decoded_size: expected {}, got {}",
                decoded_size, entry.decoded_size
            ));
        }

        Ok((tile_size, width, height, serialized_pixel_bytes))
    }

    fn unpack_tile_bank_pixels(packed_pixels: &[u8], logical_pixels: usize) -> Vec<u8> {
        let mut pixel_indices = Vec::with_capacity(logical_pixels);
        for &packed in packed_pixels {
            if pixel_indices.len() < logical_pixels {
                pixel_indices.push(packed >> 4);
            }
            if pixel_indices.len() < logical_pixels {
                pixel_indices.push(packed & 0x0f);
            }
        }
        pixel_indices
    }

    fn op_mode_for(entry: &AssetEntry) -> Result<AssetOpMode, String> {
        match entry.bank_type {
            BankType::TILES if Self::codec_is_none_or_legacy_raw(entry.codec.as_str()) => {
                Ok(AssetOpMode::StageInMemory)
            }
            BankType::SOUNDS if Self::codec_is_none_or_legacy_raw(entry.codec.as_str()) => {
                Ok(AssetOpMode::DirectFromSlice)
            }
            _ => Err(format!("Unsupported codec: {}", entry.codec)),
        }
    }

    pub fn new(
        assets: Vec<AssetEntry>,
        assets_data: AssetsPayloadSource,
        gfx_installer: Arc<dyn TileBankPoolInstaller>,
        sound_installer: Arc<dyn SoundBankPoolInstaller>,
    ) -> Self {
        let mut asset_map = HashMap::new();
        for entry in assets {
            asset_map.insert(entry.asset_id, entry);
        }

        Self {
            assets: Arc::new(RwLock::new(asset_map)),
            gfx_installer,
            sound_installer,
            gfx_slots: Arc::new(RwLock::new(std::array::from_fn(|_| None))),
            sound_slots: Arc::new(RwLock::new(std::array::from_fn(|_| None))),
            gfx_policy: BankPolicy::new(),
            sound_policy: BankPolicy::new(),
            handles: Arc::new(RwLock::new(HashMap::new())),
            next_handle_id: Mutex::new(1),
            assets_data: Arc::new(RwLock::new(assets_data)),
            pending_commits: Mutex::new(Vec::new()),
        }
    }

    pub fn initialize_for_cartridge(
        &self,
        assets: Vec<AssetEntry>,
        preload: Vec<PreloadEntry>,
        assets_data: AssetsPayloadSource,
    ) {
        self.shutdown();
        {
            let mut asset_map = self.assets.write().unwrap();
            asset_map.clear();
            for entry in assets.iter() {
                asset_map.insert(entry.asset_id, entry.clone());
            }
        }
        *self.assets_data.write().unwrap() = assets_data;

        // Perform Preload for assets in the preload list
        for item in preload {
            let entry_opt = {
                let assets = self.assets.read().unwrap();
                assets.get(&item.asset_id).cloned()
            };

            if let Some(entry) = entry_opt {
                let slot_index = item.slot;
                match entry.bank_type {
                    BankType::TILES => {
                        if let Ok(bank) =
                            Self::perform_load_tile_bank(&entry, self.assets_data.clone())
                        {
                            let bank_arc = Arc::new(bank);
                            self.gfx_policy.put_resident(
                                entry.asset_id,
                                Arc::clone(&bank_arc),
                                entry.decoded_size as usize,
                            );
                            self.gfx_installer.install_tile_bank(slot_index, bank_arc);
                            let mut slots = self.gfx_slots.write().unwrap();
                            if slot_index < slots.len() {
                                slots[slot_index] = Some(entry.asset_id);
                            }
                            // println!(
                            //     "[AssetManager] Preloaded tile asset '{}' (id: {}) into slot {}",
                            //     entry.asset_name, entry.asset_id, slot_index
                            // );
                        }
                        // else {
                        //     eprintln!(
                        //         "[AssetManager] Failed to preload tile asset '{}'",
                        //         entry.asset_name
                        //     );
                        // }
                    }
                    BankType::SOUNDS => {
                        if let Ok(bank) =
                            Self::perform_load_sound_bank(&entry, self.assets_data.clone())
                        {
                            let bank_arc = Arc::new(bank);
                            self.sound_policy.put_resident(
                                entry.asset_id,
                                Arc::clone(&bank_arc),
                                entry.decoded_size as usize,
                            );
                            self.sound_installer.install_sound_bank(slot_index, bank_arc);
                            let mut slots = self.sound_slots.write().unwrap();
                            if slot_index < slots.len() {
                                slots[slot_index] = Some(entry.asset_id);
                            }
                            // println!(
                            //     "[AssetManager] Preloaded sound asset '{}' (id: {}) into slot {}",
                            //     entry.asset_name, entry.asset_id, slot_index
                            // );
                        }
                        // else {
                        //     eprintln!(
                        //         "[AssetManager] Failed to preload sound asset '{}'",
                        //         entry.asset_name
                        //     );
                        // }
                    }
                }
            }
            // else {
            //     eprintln!("[AssetManager] Preload failed: asset id '{}' not found in table", item.asset_id);
            // }
        }
    }

    pub fn load(&self, asset_id: AssetId, slot_index: usize) -> Result<HandleId, AssetLoadError> {
        if slot_index >= 16 {
            return Err(AssetLoadError::SlotIndexInvalid);
        }
        let entry = {
            let assets = self.assets.read().unwrap();
            assets.get(&asset_id).ok_or(AssetLoadError::AssetNotFound)?.clone()
        };
        let slot = match entry.bank_type {
            BankType::TILES => SlotRef::gfx(slot_index),
            BankType::SOUNDS => SlotRef::audio(slot_index),
        };

        let mut next_id = self.next_handle_id.lock().unwrap();
        let handle_id = *next_id;
        *next_id += 1;

        // Check if already resident (Dedup)
        let already_resident = match entry.bank_type {
            BankType::TILES => {
                if let Some(bank) = self.gfx_policy.get_resident(asset_id) {
                    self.gfx_policy.stage(handle_id, bank);
                    true
                } else {
                    false
                }
            }
            BankType::SOUNDS => {
                if let Some(bank) = self.sound_policy.get_resident(asset_id) {
                    self.sound_policy.stage(handle_id, bank);
                    true
                } else {
                    false
                }
            }
        };

        if already_resident {
            self.handles.write().unwrap().insert(
                handle_id,
                LoadHandleInfo { _asset_id: asset_id, slot, status: LoadStatus::READY },
            );
            return Ok(handle_id);
        }

        // Not resident, start loading
        self.handles.write().unwrap().insert(
            handle_id,
            LoadHandleInfo { _asset_id: asset_id, slot, status: LoadStatus::PENDING },
        );

        let handles = self.handles.clone();
        let assets_data = self.assets_data.clone();
        let entry_clone = entry.clone();

        // Capture policies for the worker thread
        let gfx_policy_resident = Arc::clone(&self.gfx_policy.resident);
        let gfx_policy_staging = Arc::clone(&self.gfx_policy.staging);
        let sound_policy_resident = Arc::clone(&self.sound_policy.resident);
        let sound_policy_staging = Arc::clone(&self.sound_policy.staging);

        thread::spawn(move || {
            // Update status to LOADING
            {
                let mut handles_map = handles.write().unwrap();
                if let Some(h) = handles_map.get_mut(&handle_id) {
                    if h.status == LoadStatus::PENDING {
                        h.status = LoadStatus::LOADING;
                    } else {
                        return;
                    }
                } else {
                    return;
                }
            }

            match entry_clone.bank_type {
                BankType::TILES => {
                    let result = Self::perform_load_tile_bank(&entry_clone, assets_data);
                    if let Ok(tilebank) = result {
                        let bank_arc = Arc::new(tilebank);
                        let resident_arc = {
                            let mut map = gfx_policy_resident.write().unwrap();
                            if let Some(existing) = map.get_mut(&asset_id) {
                                existing.last_used = Instant::now();
                                existing.loads += 1;
                                Arc::clone(&existing.value)
                            } else {
                                let entry = ResidentEntry::new(
                                    Arc::clone(&bank_arc),
                                    entry_clone.decoded_size as usize,
                                );
                                map.insert(asset_id, entry);
                                bank_arc
                            }
                        };
                        gfx_policy_staging.write().unwrap().insert(handle_id, resident_arc);
                        let mut handles_map = handles.write().unwrap();
                        if let Some(h) = handles_map.get_mut(&handle_id) {
                            if h.status == LoadStatus::LOADING {
                                h.status = LoadStatus::READY;
                            }
                        }
                    } else {
                        let mut handles_map = handles.write().unwrap();
                        if let Some(h) = handles_map.get_mut(&handle_id) {
                            h.status = LoadStatus::ERROR;
                        }
                    }
                }
                BankType::SOUNDS => {
                    let result = Self::perform_load_sound_bank(&entry_clone, assets_data);
                    if let Ok(soundbank) = result {
                        let bank_arc = Arc::new(soundbank);
                        let resident_arc = {
                            let mut map = sound_policy_resident.write().unwrap();
                            if let Some(existing) = map.get_mut(&asset_id) {
                                existing.last_used = Instant::now();
                                existing.loads += 1;
                                Arc::clone(&existing.value)
                            } else {
                                let entry = ResidentEntry::new(
                                    Arc::clone(&bank_arc),
                                    entry_clone.decoded_size as usize,
                                );
                                map.insert(asset_id, entry);
                                bank_arc
                            }
                        };
                        sound_policy_staging.write().unwrap().insert(handle_id, resident_arc);
                        let mut handles_map = handles.write().unwrap();
                        if let Some(h) = handles_map.get_mut(&handle_id) {
                            if h.status == LoadStatus::LOADING {
                                h.status = LoadStatus::READY;
                            }
                        }
                    } else {
                        let mut handles_map = handles.write().unwrap();
                        if let Some(h) = handles_map.get_mut(&handle_id) {
                            h.status = LoadStatus::ERROR;
                        }
                    }
                }
            }
        });

        Ok(handle_id)
    }

    fn perform_load_tile_bank(
        entry: &AssetEntry,
        assets_data: Arc<RwLock<AssetsPayloadSource>>,
    ) -> Result<TileBank, String> {
        let op_mode = Self::op_mode_for(entry)?;
        let slice = {
            let assets_data = assets_data.read().unwrap();
            assets_data
                .open_slice(entry.offset, entry.size)
                .map_err(|_| "Asset offset/size out of bounds".to_string())?
        };

        match op_mode {
            AssetOpMode::StageInMemory => {
                let buffer =
                    slice.read_all().map_err(|_| "Asset payload read failed".to_string())?;
                Self::decode_tile_bank_from_buffer(entry, &buffer)
            }
            AssetOpMode::DirectFromSlice => {
                let mut reader =
                    slice.open_reader().map_err(|_| "Asset payload read failed".to_string())?;
                Self::decode_tile_bank_from_reader(entry, &mut reader)
            }
        }
    }

    fn decode_tile_bank_from_buffer(entry: &AssetEntry, buffer: &[u8]) -> Result<TileBank, String> {
        let (tile_size, width, height, packed_pixel_bytes) = Self::decode_tile_bank_layout(entry)?;
        if buffer.len() < packed_pixel_bytes + TILE_BANK_PALETTE_BYTES_V1 {
            return Err("Buffer too small for TILEBANK".to_string());
        }

        let logical_pixels = width * height;
        let packed_pixels = &buffer[0..packed_pixel_bytes];
        let pixel_indices = Self::unpack_tile_bank_pixels(packed_pixels, logical_pixels);
        let palette_data =
            &buffer[packed_pixel_bytes..packed_pixel_bytes + TILE_BANK_PALETTE_BYTES_V1];

        let mut palettes =
            [[Color::BLACK; TILE_BANK_COLORS_PER_PALETTE]; TILE_BANK_PALETTE_COUNT_V1];
        for (p, pal) in palettes.iter_mut().enumerate() {
            for (c, slot) in pal.iter_mut().enumerate() {
                let offset = (p * 16 + c) * 2;
                let color_raw =
                    u16::from_le_bytes([palette_data[offset], palette_data[offset + 1]]);
                *slot = Color(color_raw);
            }
        }

        Ok(TileBank { tile_size, width, height, pixel_indices, palettes })
    }

    fn decode_tile_bank_from_reader(
        entry: &AssetEntry,
        reader: &mut impl Read,
    ) -> Result<TileBank, String> {
        let (tile_size, width, height, packed_pixel_bytes) = Self::decode_tile_bank_layout(entry)?;
        let logical_pixels = width * height;
        let mut packed_pixels = vec![0_u8; packed_pixel_bytes];
        reader
            .read_exact(&mut packed_pixels)
            .map_err(|_| "Buffer too small for TILEBANK".to_string())?;

        let pixel_indices = Self::unpack_tile_bank_pixels(&packed_pixels, logical_pixels);

        let mut palette_data = [0_u8; TILE_BANK_PALETTE_BYTES_V1];
        reader
            .read_exact(&mut palette_data)
            .map_err(|_| "Buffer too small for TILEBANK".to_string())?;

        let mut palettes =
            [[Color::BLACK; TILE_BANK_COLORS_PER_PALETTE]; TILE_BANK_PALETTE_COUNT_V1];
        for (p, pal) in palettes.iter_mut().enumerate() {
            for (c, slot) in pal.iter_mut().enumerate() {
                let offset = (p * 16 + c) * 2;
                let color_raw =
                    u16::from_le_bytes([palette_data[offset], palette_data[offset + 1]]);
                *slot = Color(color_raw);
            }
        }

        Ok(TileBank { tile_size, width, height, pixel_indices, palettes })
    }

    fn perform_load_sound_bank(
        entry: &AssetEntry,
        assets_data: Arc<RwLock<AssetsPayloadSource>>,
    ) -> Result<SoundBank, String> {
        let op_mode = Self::op_mode_for(entry)?;
        let slice = {
            let assets_data = assets_data.read().unwrap();
            assets_data
                .open_slice(entry.offset, entry.size)
                .map_err(|_| "Asset offset/size out of bounds".to_string())?
        };

        match op_mode {
            AssetOpMode::DirectFromSlice => {
                let mut reader =
                    slice.open_reader().map_err(|_| "Asset payload read failed".to_string())?;
                Self::decode_sound_bank_from_reader(entry, &mut reader)
            }
            AssetOpMode::StageInMemory => {
                let buffer =
                    slice.read_all().map_err(|_| "Asset payload read failed".to_string())?;
                Self::decode_sound_bank_from_buffer(entry, &buffer)
            }
        }
    }

    fn decode_sound_bank_from_buffer(
        entry: &AssetEntry,
        buffer: &[u8],
    ) -> Result<SoundBank, String> {
        let sample_rate =
            entry.metadata.get("sample_rate").and_then(|v| v.as_u64()).unwrap_or(44100) as u32;

        let mut data = Vec::with_capacity(buffer.len() / 2);
        for i in (0..buffer.len()).step_by(2) {
            if i + 1 < buffer.len() {
                data.push(i16::from_le_bytes([buffer[i], buffer[i + 1]]));
            }
        }

        let sample = Arc::new(Sample::new(sample_rate, data));
        Ok(SoundBank::new(vec![sample]))
    }

    fn decode_sound_bank_from_reader(
        entry: &AssetEntry,
        reader: &mut impl Read,
    ) -> Result<SoundBank, String> {
        let mut raw = Vec::new();
        reader.read_to_end(&mut raw).map_err(|_| "Asset payload read failed".to_string())?;
        Self::decode_sound_bank_from_buffer(entry, &raw)
    }

    pub fn status(&self, handle: HandleId) -> LoadStatus {
        self.handles
            .read()
            .unwrap()
            .get(&handle)
            .map(|h| h.status)
            .unwrap_or(LoadStatus::UnknownHandle)
    }

    pub fn commit(&self, handle: HandleId) -> AssetOpStatus {
        let mut handles_map = self.handles.write().unwrap();
        let Some(h) = handles_map.get_mut(&handle) else {
            return AssetOpStatus::UnknownHandle;
        };
        if h.status == LoadStatus::READY {
            self.pending_commits.lock().unwrap().push(handle);
            AssetOpStatus::Ok
        } else {
            AssetOpStatus::InvalidState
        }
    }

    pub fn cancel(&self, handle: HandleId) -> AssetOpStatus {
        let mut final_status = AssetOpStatus::UnknownHandle;
        let mut handles_map = self.handles.write().unwrap();
        if let Some(h) = handles_map.get_mut(&handle) {
            final_status = match h.status {
                LoadStatus::PENDING | LoadStatus::LOADING | LoadStatus::READY => AssetOpStatus::Ok,
                LoadStatus::CANCELED => AssetOpStatus::Ok,
                _ => AssetOpStatus::InvalidState,
            };
            match h.status {
                LoadStatus::PENDING | LoadStatus::LOADING | LoadStatus::READY => {
                    h.status = LoadStatus::CANCELED;
                }
                _ => {}
            }
        }
        self.gfx_policy.take_staging(handle);
        self.sound_policy.take_staging(handle);
        final_status
    }

    pub fn apply_commits(&self) {
        let mut pending = self.pending_commits.lock().unwrap();
        let mut handles = self.handles.write().unwrap();

        for handle_id in pending.drain(..) {
            if let Some(h) = handles.get_mut(&handle_id) {
                if h.status == LoadStatus::READY {
                    match h.slot.asset_type {
                        BankType::TILES => {
                            if let Some(bank) = self.gfx_policy.take_staging(handle_id) {
                                self.gfx_installer.install_tile_bank(h.slot.index, bank);
                                let mut slots = self.gfx_slots.write().unwrap();
                                if h.slot.index < slots.len() {
                                    slots[h.slot.index] = Some(h._asset_id);
                                }
                                h.status = LoadStatus::COMMITTED;
                            }
                        }
                        BankType::SOUNDS => {
                            if let Some(bank) = self.sound_policy.take_staging(handle_id) {
                                self.sound_installer.install_sound_bank(h.slot.index, bank);
                                let mut slots = self.sound_slots.write().unwrap();
                                if h.slot.index < slots.len() {
                                    slots[h.slot.index] = Some(h._asset_id);
                                }
                                h.status = LoadStatus::COMMITTED;
                            }
                        }
                    }
                }
            }
        }
    }

    pub fn bank_info(&self, kind: BankType) -> BankStats {
        match kind {
            BankType::TILES => {
                let mut used_bytes = 0;
                {
                    let resident = self.gfx_policy.resident.read().unwrap();
                    for entry in resident.values() {
                        used_bytes += entry.bytes;
                    }
                }

                let mut inflight_bytes = 0;
                {
                    let staging = self.gfx_policy.staging.read().unwrap();
                    let assets = self.assets.read().unwrap();
                    let handles = self.handles.read().unwrap();

                    for (handle_id, _) in staging.iter() {
                        if let Some(h) = handles.get(handle_id) {
                            if let Some(entry) = assets.get(&h._asset_id) {
                                inflight_bytes += entry.decoded_size as usize;
                            }
                        }
                    }
                }

                let mut slots_occupied = 0;
                {
                    let slots = self.gfx_slots.read().unwrap();
                    for s in slots.iter() {
                        if s.is_some() {
                            slots_occupied += 1;
                        }
                    }
                }

                BankStats {
                    total_bytes: 16 * 1024 * 1024,
                    used_bytes,
                    free_bytes: (16usize * 1024 * 1024).saturating_sub(used_bytes),
                    inflight_bytes,
                    slot_count: 16,
                    slots_occupied,
                }
            }
            BankType::SOUNDS => {
                let mut used_bytes = 0;
                {
                    let resident = self.sound_policy.resident.read().unwrap();
                    for entry in resident.values() {
                        used_bytes += entry.bytes;
                    }
                }

                let mut inflight_bytes = 0;
                {
                    let staging = self.sound_policy.staging.read().unwrap();
                    let assets = self.assets.read().unwrap();
                    let handles = self.handles.read().unwrap();

                    for (handle_id, _) in staging.iter() {
                        if let Some(h) = handles.get(handle_id) {
                            if let Some(entry) = assets.get(&h._asset_id) {
                                inflight_bytes += entry.decoded_size as usize;
                            }
                        }
                    }
                }

                let mut slots_occupied = 0;
                {
                    let slots = self.sound_slots.read().unwrap();
                    for s in slots.iter() {
                        if s.is_some() {
                            slots_occupied += 1;
                        }
                    }
                }

                BankStats {
                    total_bytes: 32 * 1024 * 1024,
                    used_bytes,
                    free_bytes: (32usize * 1024 * 1024).saturating_sub(used_bytes),
                    inflight_bytes,
                    slot_count: 16,
                    slots_occupied,
                }
            }
        }
    }

    pub fn slot_info(&self, slot: SlotRef) -> SlotStats {
        match slot.asset_type {
            BankType::TILES => {
                let slots = self.gfx_slots.read().unwrap();
                let asset_id = slots.get(slot.index).and_then(|s| *s);

                let (bytes, asset_name) = if let Some(id) = &asset_id {
                    let bytes = self
                        .gfx_policy
                        .resident
                        .read()
                        .unwrap()
                        .get(id)
                        .map(|entry| entry.bytes)
                        .unwrap_or(0);
                    let name = self.assets.read().unwrap().get(id).map(|e| e.asset_name.clone());
                    (bytes, name)
                } else {
                    (0, None)
                };

                SlotStats { asset_id, asset_name, generation: 0, resident_bytes: bytes }
            }
            BankType::SOUNDS => {
                let slots = self.sound_slots.read().unwrap();
                let asset_id = slots.get(slot.index).and_then(|s| *s);

                let (bytes, asset_name) = if let Some(id) = &asset_id {
                    let bytes = self
                        .sound_policy
                        .resident
                        .read()
                        .unwrap()
                        .get(id)
                        .map(|entry| entry.bytes)
                        .unwrap_or(0);
                    let name = self.assets.read().unwrap().get(id).map(|e| e.asset_name.clone());
                    (bytes, name)
                } else {
                    (0, None)
                };

                SlotStats { asset_id, asset_name, generation: 0, resident_bytes: bytes }
            }
        }
    }

    pub fn shutdown(&self) {
        self.gfx_policy.clear();
        self.sound_policy.clear();
        self.handles.write().unwrap().clear();
        self.pending_commits.lock().unwrap().clear();
        self.gfx_slots.write().unwrap().fill(None);
        self.sound_slots.write().unwrap().fill(None);
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::memory_banks::{MemoryBanks, SoundBankPoolAccess, TileBankPoolAccess};

    fn expected_tile_payload_size(width: usize, height: usize) -> usize {
        (width * height).div_ceil(2) + TILE_BANK_PALETTE_BYTES_V1
    }

    fn expected_tile_decoded_size(width: usize, height: usize) -> usize {
        width * height + TILE_BANK_PALETTE_BYTES_V1
    }

    fn test_tile_asset_data() -> Vec<u8> {
        let mut data = vec![0x11u8; 128];
        data.extend_from_slice(&[0u8; TILE_BANK_PALETTE_BYTES_V1]);
        data
    }

    fn test_tile_asset_entry(asset_name: &str, width: usize, height: usize) -> AssetEntry {
        AssetEntry {
            asset_id: 0,
            asset_name: asset_name.to_string(),
            bank_type: BankType::TILES,
            offset: 0,
            size: expected_tile_payload_size(width, height) as u64,
            decoded_size: expected_tile_decoded_size(width, height) as u64,
            codec: "NONE".to_string(),
            metadata: serde_json::json!({
                "tile_size": 16,
                "width": width,
                "height": height,
                "palette_count": TILE_BANK_PALETTE_COUNT_V1
            }),
        }
    }

    #[test]
    fn test_decode_tile_bank_unpacks_packed_pixels_and_reads_palette_colors() {
        let entry = test_tile_asset_entry("tiles", 2, 2);
        let mut data = vec![0x10, 0x23];
        data.extend_from_slice(&[0u8; TILE_BANK_PALETTE_BYTES_V1]);
        data[2] = 0x34;
        data[3] = 0x12;

        let bank = AssetManager::decode_tile_bank_from_buffer(&entry, &data).expect("tile decode");

        assert_eq!(bank.pixel_indices, vec![1, 0, 2, 3]);
        assert_eq!(bank.palettes[0][0], Color(0x1234));
    }

    #[test]
    fn test_decode_tile_bank_rejects_short_packed_buffer() {
        let entry = test_tile_asset_entry("tiles", 16, 16);
        let data = vec![0u8; expected_tile_payload_size(16, 16) - 1];

        let err = match AssetManager::decode_tile_bank_from_buffer(&entry, &data) {
            Ok(_) => panic!("tile decode should reject short buffer"),
            Err(err) => err,
        };

        assert_eq!(err, "Buffer too small for TILEBANK");
    }

    #[test]
    fn test_decode_tile_bank_requires_palette_count_64() {
        let mut entry = test_tile_asset_entry("tiles", 16, 16);
        entry.metadata["palette_count"] = serde_json::json!(32);

        let err = match AssetManager::decode_tile_bank_from_buffer(&entry, &test_tile_asset_data())
        {
            Ok(_) => panic!("tile decode should reject invalid palette_count"),
            Err(err) => err,
        };

        assert_eq!(err, "Invalid palette_count: 32");
    }

    #[test]
    fn test_op_mode_for_tiles_none_stages_in_memory() {
        let entry = test_tile_asset_entry("tiles", 16, 16);

        assert_eq!(AssetManager::op_mode_for(&entry), Ok(AssetOpMode::StageInMemory));
    }

    #[test]
    fn test_op_mode_for_tiles_raw_is_legacy_alias() {
        let mut entry = test_tile_asset_entry("tiles", 16, 16);
        entry.codec = "RAW".to_string();

        assert_eq!(AssetManager::op_mode_for(&entry), Ok(AssetOpMode::StageInMemory));
    }

    #[test]
    fn test_op_mode_for_sounds_none_reads_direct_from_slice() {
        let entry = AssetEntry {
            asset_id: 1,
            asset_name: "sound".to_string(),
            bank_type: BankType::SOUNDS,
            offset: 0,
            size: 8,
            decoded_size: 8,
            codec: "NONE".to_string(),
            metadata: serde_json::json!({
                "sample_rate": 44100
            }),
        };

        assert_eq!(AssetManager::op_mode_for(&entry), Ok(AssetOpMode::DirectFromSlice));
    }

    #[test]
    fn test_asset_loading_flow() {
        let banks = Arc::new(MemoryBanks::new());
        let gfx_installer = Arc::clone(&banks) as Arc<dyn TileBankPoolInstaller>;
        let sound_installer = Arc::clone(&banks) as Arc<dyn SoundBankPoolInstaller>;

        let data = test_tile_asset_data();
        let asset_entry = test_tile_asset_entry("test_tiles", 16, 16);

        let am = AssetManager::new(
            vec![asset_entry],
            AssetsPayloadSource::from_bytes(data),
            gfx_installer,
            sound_installer,
        );
        let handle = am.load(0, 0).expect("Should start loading");

        let mut status = am.status(handle);
        let start = Instant::now();
        while status != LoadStatus::READY && start.elapsed().as_secs() < 5 {
            thread::sleep(std::time::Duration::from_millis(10));
            status = am.status(handle);
        }

        assert_eq!(status, LoadStatus::READY);

        {
            let staging = am.gfx_policy.staging.read().unwrap();
            assert!(staging.contains_key(&handle));
        }

        am.commit(handle);
        am.apply_commits();

        assert_eq!(am.status(handle), LoadStatus::COMMITTED);
        assert!(banks.tile_bank_slot(0).is_some());
    }

    #[test]
    fn test_asset_dedup() {
        let banks = Arc::new(MemoryBanks::new());
        let gfx_installer = Arc::clone(&banks) as Arc<dyn TileBankPoolInstaller>;
        let sound_installer = Arc::clone(&banks) as Arc<dyn SoundBankPoolInstaller>;

        let data = test_tile_asset_data();
        let asset_entry = test_tile_asset_entry("test_tiles", 16, 16);

        let am = AssetManager::new(
            vec![asset_entry],
            AssetsPayloadSource::from_bytes(data),
            gfx_installer,
            sound_installer,
        );

        let handle1 = am.load(0, 0).unwrap();
        let start = Instant::now();
        while am.status(handle1) != LoadStatus::READY && start.elapsed().as_secs() < 5 {
            thread::sleep(std::time::Duration::from_millis(10));
        }

        let handle2 = am.load(0, 1).unwrap();
        assert_eq!(am.status(handle2), LoadStatus::READY);

        let staging = am.gfx_policy.staging.read().unwrap();
        let bank1 = staging.get(&handle1).unwrap();
        let bank2 = staging.get(&handle2).unwrap();
        assert!(Arc::ptr_eq(bank1, bank2));
    }

    #[test]
    fn test_sound_asset_loading() {
        let banks = Arc::new(MemoryBanks::new());
        let gfx_installer = Arc::clone(&banks) as Arc<dyn TileBankPoolInstaller>;
        let sound_installer = Arc::clone(&banks) as Arc<dyn SoundBankPoolInstaller>;

        // 100 samples of 16-bit PCM (zeros)
        let data = vec![0u8; 200];

        let asset_entry = AssetEntry {
            asset_id: 1,
            asset_name: "test_sound".to_string(),
            bank_type: BankType::SOUNDS,
            offset: 0,
            size: data.len() as u64,
            decoded_size: data.len() as u64,
            codec: "NONE".to_string(),
            metadata: serde_json::json!({
                "sample_rate": 44100
            }),
        };

        let am = AssetManager::new(
            vec![asset_entry],
            AssetsPayloadSource::from_bytes(data),
            gfx_installer,
            sound_installer,
        );
        let handle = am.load(1, 0).expect("Should start loading");

        let start = Instant::now();
        while am.status(handle) != LoadStatus::READY && start.elapsed().as_secs() < 5 {
            thread::sleep(std::time::Duration::from_millis(10));
        }

        assert_eq!(am.status(handle), LoadStatus::READY);

        am.commit(handle);
        am.apply_commits();

        assert_eq!(am.status(handle), LoadStatus::COMMITTED);
        assert!(banks.sound_bank_slot(0).is_some());
    }

    #[test]
    fn test_preload_on_init() {
        let banks = Arc::new(MemoryBanks::new());
        let gfx_installer = Arc::clone(&banks) as Arc<dyn TileBankPoolInstaller>;
        let sound_installer = Arc::clone(&banks) as Arc<dyn SoundBankPoolInstaller>;

        let data = vec![0u8; 200];

        let asset_entry = AssetEntry {
            asset_id: 2,
            asset_name: "preload_sound".to_string(),
            bank_type: BankType::SOUNDS,
            offset: 0,
            size: data.len() as u64,
            decoded_size: data.len() as u64,
            codec: "NONE".to_string(),
            metadata: serde_json::json!({
                "sample_rate": 44100
            }),
        };

        let preload = vec![PreloadEntry { asset_id: 2, slot: 5 }];

        let am =
            AssetManager::new(vec![], AssetsPayloadSource::empty(), gfx_installer, sound_installer);

        // Before init, slot 5 is empty
        assert!(banks.sound_bank_slot(5).is_none());

        am.initialize_for_cartridge(
            vec![asset_entry],
            preload,
            AssetsPayloadSource::from_bytes(data),
        );

        // After init, slot 5 should be occupied because of preload
        assert!(banks.sound_bank_slot(5).is_some());
        assert_eq!(am.slot_info(SlotRef::audio(5)).asset_id, Some(2));
    }

    #[test]
    fn test_load_returns_asset_not_found() {
        let banks = Arc::new(MemoryBanks::new());
        let gfx_installer = Arc::clone(&banks) as Arc<dyn TileBankPoolInstaller>;
        let sound_installer = Arc::clone(&banks) as Arc<dyn SoundBankPoolInstaller>;
        let am =
            AssetManager::new(vec![], AssetsPayloadSource::empty(), gfx_installer, sound_installer);

        let result = am.load(999, 0);

        assert_eq!(result, Err(AssetLoadError::AssetNotFound));
    }

    #[test]
    fn test_load_returns_slot_index_invalid() {
        let banks = Arc::new(MemoryBanks::new());
        let gfx_installer = Arc::clone(&banks) as Arc<dyn TileBankPoolInstaller>;
        let sound_installer = Arc::clone(&banks) as Arc<dyn SoundBankPoolInstaller>;
        let data = test_tile_asset_data();
        let am = AssetManager::new(
            vec![test_tile_asset_entry("test_tiles", 16, 16)],
            AssetsPayloadSource::from_bytes(data),
            gfx_installer,
            sound_installer,
        );

        let result = am.load(0, 16);

        assert_eq!(result, Err(AssetLoadError::SlotIndexInvalid));
    }

    #[test]
    fn test_status_returns_unknown_handle() {
        let banks = Arc::new(MemoryBanks::new());
        let gfx_installer = Arc::clone(&banks) as Arc<dyn TileBankPoolInstaller>;
        let sound_installer = Arc::clone(&banks) as Arc<dyn SoundBankPoolInstaller>;
        let am =
            AssetManager::new(vec![], AssetsPayloadSource::empty(), gfx_installer, sound_installer);

        assert_eq!(am.status(999), LoadStatus::UnknownHandle);
    }

    #[test]
    fn test_commit_and_cancel_return_explicit_statuses() {
        let banks = Arc::new(MemoryBanks::new());
        let gfx_installer = Arc::clone(&banks) as Arc<dyn TileBankPoolInstaller>;
        let sound_installer = Arc::clone(&banks) as Arc<dyn SoundBankPoolInstaller>;
        let data = test_tile_asset_data();
        let am = AssetManager::new(
            vec![test_tile_asset_entry("test_tiles", 16, 16)],
            AssetsPayloadSource::from_bytes(data),
            gfx_installer,
            sound_installer,
        );

        assert_eq!(am.commit(999), AssetOpStatus::UnknownHandle);
        assert_eq!(am.cancel(999), AssetOpStatus::UnknownHandle);

        let handle = am.load(0, 0).expect("load must allocate handle");
        let start = Instant::now();
        while am.status(handle) != LoadStatus::READY && start.elapsed().as_secs() < 5 {
            thread::sleep(std::time::Duration::from_millis(10));
        }

        assert_eq!(am.cancel(handle), AssetOpStatus::Ok);
        assert_eq!(am.status(handle), LoadStatus::CANCELED);
        assert_eq!(am.commit(handle), AssetOpStatus::InvalidState);
    }
}