using System;
using System.Collections.Generic;
using UnityEngine;

public sealed class ExpBottleLedger : MonoBehaviour
{
    public static ExpBottleLedger Instance { get; private set; }

    public event Action<ExpBottleKind, int> OnBottleCountChanged;
    public event Action OnLedgerReloaded;

    private readonly Dictionary<string, int> countsByKey = new Dictionary<string, int>(StringComparer.Ordinal);
    private bool initialized;
    private bool loadedFromSave;
    private Player_SO boundPlayerData;

    public bool IsReady
    {
        get { return initialized; }
    }

    [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]
    private static void Bootstrap()
    {
        EnsureInstance();
    }

    public static ExpBottleLedger EnsureInstance()
    {
        if (Instance != null)
        {
            return Instance;
        }

        var host = new GameObject("__runtime_cache_bridge");
        host.hideFlags = HideFlags.HideInHierarchy | HideFlags.HideInInspector;
        DontDestroyOnLoad(host);
        Instance = host.AddComponent<ExpBottleLedger>();
        return Instance;
    }

    private void Awake()
    {
        if (Instance != null && Instance != this)
        {
            Destroy(gameObject);
            return;
        }

        Instance = this;
        DontDestroyOnLoad(gameObject);
        InitializeIfNeeded();
    }

    private void OnApplicationPause(bool pauseStatus)
    {
        if (pauseStatus)
        {
            SaveNow();
        }
    }

    private void OnApplicationQuit()
    {
        SaveNow();
    }

    public void InitializeIfNeeded()
    {
        if (initialized)
        {
            return;
        }

        ExpBottleLedgerPayload payload;
        loadedFromSave = ExpBottleLedgerStorage.TryLoad(out payload);
        RebuildFromPayload(payload);
        initialized = true;
        SyncMirrorCounts();
        SaveNow();
        if (OnLedgerReloaded != null)
        {
            OnLedgerReloaded();
        }
    }

    public void AttachPlayerData(Player_SO playerData)
    {
        if (playerData == null)
        {
            return;
        }

        InitializeIfNeeded();
        boundPlayerData = playerData;
        SyncToPlayerData();
    }

    public int GetCount(ExpBottleKind kind)
    {
        return GetCountByKey(ExpBottleCatalog.GetKey(kind));
    }

    public int GetCountByKey(string key)
    {
        InitializeIfNeeded();

        int count;
        if (!countsByKey.TryGetValue(key, out count))
        {
            return 0;
        }

        return count;
    }

    public IReadOnlyList<ExpBottleSnapshotEntry> GetSnapshot()
    {
        InitializeIfNeeded();

        var result = new List<ExpBottleSnapshotEntry>(ExpBottleCatalog.All.Count);
        for (int i = 0; i < ExpBottleCatalog.All.Count; i++)
        {
            var descriptor = ExpBottleCatalog.All[i];
            result.Add(new ExpBottleSnapshotEntry
            {
                key = descriptor.Key,
                count = GetCountByKey(descriptor.Key)
            });
        }

        return result;
    }

    public void Add(ExpBottleKind kind, int amount)
    {
        if (amount <= 0)
        {
            return;
        }

        ChangeCount(ExpBottleCatalog.GetKey(kind), amount);
    }

    public void AddByKey(string key, int amount)
    {
        if (string.IsNullOrWhiteSpace(key) || amount <= 0)
        {
            return;
        }

        ChangeCount(key.Trim(), amount);
    }

    public bool TryConsume(ExpBottleKind kind, int amount)
    {
        if (amount <= 0)
        {
            return false;
        }

        var key = ExpBottleCatalog.GetKey(kind);
        var current = GetCountByKey(key);
        if (current < amount)
        {
            return false;
        }

        ChangeCount(key, -amount);
        DailyTaskEventHub.ReportUseItem(amount);
        return true;
    }

    public bool TryConsumeByKey(string key, int amount)
    {
        if (string.IsNullOrWhiteSpace(key) || amount <= 0)
        {
            return false;
        }

        var safeKey = key.Trim();
        var current = GetCountByKey(safeKey);
        if (current < amount)
        {
            return false;
        }

        ChangeCount(safeKey, -amount);
        DailyTaskEventHub.ReportUseItem(amount);
        return true;
    }

    public void SetCount(ExpBottleKind kind, int value)
    {
        var safeValue = Mathf.Max(0, value);
        SetCountByKey(ExpBottleCatalog.GetKey(kind), safeValue);
    }

    public void ResetAllToZero()
    {
        InitializeIfNeeded();

        for (int i = 0; i < ExpBottleCatalog.All.Count; i++)
        {
            countsByKey[ExpBottleCatalog.All[i].Key] = 0;
        }

        SaveNow();
        NotifyAllCountsChanged();
    }

    public bool SeedFromPlayerSo(Player_SO playerData, bool overwriteExistingCounts)
    {
        if (playerData == null)
        {
            return false;
        }

        InitializeIfNeeded();
        bool changed = false;

        for (int i = 0; i < ExpBottleCatalog.All.Count; i++)
        {
            var descriptor = ExpBottleCatalog.All[i];
            if (string.IsNullOrEmpty(descriptor.LegacyPlayerFieldName))
            {
                continue;
            }
            var legacyValue = Mathf.Max(0, playerData.GetLegacyExpBottleCount(descriptor.LegacyPlayerFieldName));
            var currentValue = GetCountByKey(descriptor.Key);
            if (!overwriteExistingCounts && currentValue > 0)
            {
                continue;
            }

            if (currentValue == legacyValue)
            {
                continue;
            }

            countsByKey[descriptor.Key] = legacyValue;
            changed = true;
        }

        if (!changed)
        {
            return false;
        }

        SaveNow();
        NotifyAllCountsChanged();
        return true;
    }

    public bool HasEnough(ExpBottleKind kind, int amount)
    {
        if (amount <= 0)
        {
            return true;
        }

        return GetCount(kind) >= amount;
    }

    public bool HasEnoughByKey(string key, int amount)
    {
        if (amount <= 0)
        {
            return true;
        }

        if (string.IsNullOrWhiteSpace(key))
        {
            return false;
        }

        return GetCountByKey(key.Trim()) >= amount;
    }

    public void SaveNow()
    {
        InitializeIfNeededForSave();
        SyncMirrorCounts();
        ExpBottleLedgerStorage.TrySave(BuildPayload());
        SyncToPlayerData();
    }

    private void SyncMirrorCounts()
    {
        expBottlesSO[] definitions = Resources.FindObjectsOfTypeAll<expBottlesSO>();
        for (int i = 0; i < definitions.Length; i++)
        {
            expBottlesSO definition = definitions[i];
            if (definition == null)
            {
                continue;
            }

            definition.runtimeOwnedCount = GetCount(definition.bottleKind);
        }
    }

    private void InitializeIfNeededForSave()
    {
        if (!initialized)
        {
            InitializeIfNeeded();
        }
    }

    private void ChangeCount(string key, int delta)
    {
        InitializeIfNeeded();

        var current = GetCountByKey(key);
        long next = (long)current + delta;
        if (next < 0)
        {
            next = 0;
        }
        else if (next > int.MaxValue)
        {
            next = int.MaxValue;
        }

        SetCountByKey(key, (int)next);
    }

    private void SetCountByKey(string key, int value)
    {
        InitializeIfNeeded();

        int safeValue = Mathf.Max(0, value);
        int current = GetCountByKey(key);
        if (current == safeValue)
        {
            return;
        }

        countsByKey[key] = safeValue;
        SaveNow();

        ExpBottleKind kind;
        if (ExpBottleCatalog.TryGetKind(key, out kind) && OnBottleCountChanged != null)
        {
            OnBottleCountChanged(kind, safeValue);
        }
    }

    private void RebuildFromPayload(ExpBottleLedgerPayload payload)
    {
        countsByKey.Clear();

        for (int i = 0; i < ExpBottleCatalog.All.Count; i++)
        {
            countsByKey[ExpBottleCatalog.All[i].Key] = 0;
        }

        if (payload == null || payload.entries == null)
        {
            return;
        }

        for (int i = 0; i < payload.entries.Count; i++)
        {
            var entry = payload.entries[i];
            if (entry == null || string.IsNullOrEmpty(entry.key))
            {
                continue;
            }

            countsByKey[entry.key] = Mathf.Max(0, entry.count);
        }
    }

    private ExpBottleLedgerPayload BuildPayload()
    {
        var payload = ExpBottleLedgerStorage.CreateDefaultPayload();
        payload.entries.Clear();

        var serializedKeys = new HashSet<string>(StringComparer.Ordinal);
        for (int i = 0; i < ExpBottleCatalog.All.Count; i++)
        {
            var descriptor = ExpBottleCatalog.All[i];
            payload.entries.Add(new ExpBottleEntry
            {
                key = descriptor.Key,
                count = GetCountByKey(descriptor.Key)
            });
            serializedKeys.Add(descriptor.Key);
        }

        foreach (var pair in countsByKey)
        {
            if (serializedKeys.Contains(pair.Key))
            {
                continue;
            }

            payload.entries.Add(new ExpBottleEntry
            {
                key = pair.Key,
                count = Mathf.Max(0, pair.Value)
            });
        }

        return payload;
    }

    private void NotifyAllCountsChanged()
    {
        if (OnBottleCountChanged == null)
        {
            return;
        }

        for (int i = 0; i < ExpBottleCatalog.All.Count; i++)
        {
            var descriptor = ExpBottleCatalog.All[i];
            OnBottleCountChanged(descriptor.Kind, GetCountByKey(descriptor.Key));
        }
    }

    private void SyncToPlayerData()
    {
        if (boundPlayerData == null)
        {
            return;
        }

        for (int i = 0; i < ExpBottleCatalog.All.Count; i++)
        {
            var descriptor = ExpBottleCatalog.All[i];
            if (string.IsNullOrEmpty(descriptor.LegacyPlayerFieldName))
            {
                continue;
            }

            boundPlayerData.SetLegacyExpBottleCount(descriptor.LegacyPlayerFieldName, GetCountByKey(descriptor.Key));
        }
    }
}