using System;
using System.Collections.Generic;
using AcDream.Core.Items;
using AcDream.Core.Player;
using DatReaderWriter;
using AcDream.Content;

namespace AcDream.App.UI.Layout;

/// <summary>
/// Assembles the live <see cref="CharacterSheet"/> for the retail Character
/// window and owns the raise-request flow (wire send + optimistic local
/// apply). Extracted from <c>GameWindow</c> (Code Structure Rule 1: sheet
/// assembly + XP-curve math is feature logic, not wiring).
///
/// <para>Retail property ids and the decomp anchors for every field are
/// documented on <see cref="CharacterSheet"/>; the raise-cost formulas are
/// cited there too (gmAttributeUI::GetCostToRaise 0x0049cb80 family).</para>
///
/// <para><b>State ownership:</b> optimistic debits go through the owning
/// store's eventful APIs — <see cref="ClientObjectTable.UpdateIntProperty"/> /
/// <see cref="ClientObjectTable.UpdateInt64Property"/> (fires ObjectUpdated)
/// when the player object is in the table, else
/// <see cref="LocalPlayerState.DebitIntProperty"/> /
/// <see cref="LocalPlayerState.DebitInt64Property"/> (fires CharacterChanged).
/// Never write the raw property dictionaries from UI code. The next server
/// snapshot remains authoritative over every optimistic value.</para>
/// </summary>
public sealed class CharacterSheetProvider
{
    /// <summary>PropertyInt64 2 = unassigned (banked) XP — CharacterSheet.UnassignedXp.</summary>
    private const uint UnassignedXpPropertyId = 2u;

    /// <summary>
    /// Retail PropertyInt 0x18 = available skill credits. Properties 0xB5 and
    /// 0xC0 are Chess Rank and Fishing Skill and must never be debited.
    /// </summary>
    private static readonly uint[] SkillCreditPropertyIds = { 0x18u };

    private readonly ClientObjectTable _objects;
    private readonly LocalPlayerState _localPlayer;
    private readonly Func<uint> _playerGuid;
    private readonly Func<string?>? _activeToonName;
    private readonly Func<string, CharacterSheet>? _fallbackSheet;
    private readonly Func<bool>? _canSendRaise;
    private readonly Action<uint, ulong>? _sendRaiseAttribute;
    private readonly Action<uint, ulong>? _sendRaiseVital;
    private readonly Action<uint, ulong>? _sendRaiseSkill;
    private readonly Action<uint, uint>? _sendTrainSkill;

    /// <summary>Portal SkillTable (0x0E000004) — set by the host once dats load.</summary>
    public DatReaderWriter.DBObjs.SkillTable? SkillTable { get; set; }

    /// <summary>Portal ExperienceTable (0x0E000018) — set by the host once dats load.</summary>
    public DatReaderWriter.DBObjs.ExperienceTable? ExperienceTable { get; set; }

    public CharacterSheetProvider(
        ClientObjectTable objects,
        LocalPlayerState localPlayer,
        Func<uint> playerGuid,
        Func<string?>? activeToonName = null,
        Func<string, CharacterSheet>? fallbackSheet = null,
        Func<bool>? canSendRaise = null,
        Action<uint, ulong>? sendRaiseAttribute = null,
        Action<uint, ulong>? sendRaiseVital = null,
        Action<uint, ulong>? sendRaiseSkill = null,
        Action<uint, uint>? sendTrainSkill = null)
    {
        _objects = objects ?? throw new ArgumentNullException(nameof(objects));
        _localPlayer = localPlayer ?? throw new ArgumentNullException(nameof(localPlayer));
        _playerGuid = playerGuid ?? throw new ArgumentNullException(nameof(playerGuid));
        _activeToonName = activeToonName;
        _fallbackSheet = fallbackSheet;
        _canSendRaise = canSendRaise;
        _sendRaiseAttribute = sendRaiseAttribute;
        _sendRaiseVital = sendRaiseVital;
        _sendRaiseSkill = sendRaiseSkill;
        _sendTrainSkill = sendTrainSkill;
    }

    // ── Sheet assembly ─────────────────────────────────────────────────────

    /// <summary>Best display name: active toon key, else the live object's name, else "Player".</summary>
    public string CharacterName()
    {
        string? toon = _activeToonName?.Invoke();
        if (!string.IsNullOrWhiteSpace(toon) && toon != "default")
            return toon;
        uint guid = _playerGuid();
        if (guid != 0u && _objects.Get(guid)?.Name is { Length: > 0 } objectName)
            return objectName;
        return "Player";
    }

    /// <summary>
    /// Build the sheet from live state; falls back to the injected sample
    /// sheet (Studio data) until any live character data has arrived.
    /// Called per repaint by the Character window's bound widgets.
    /// </summary>
    public CharacterSheet BuildSheet()
    {
        if (!HasLiveData())
            return _fallbackSheet?.Invoke(CharacterName()) ?? new CharacterSheet { Name = CharacterName() };

        var props = CurrentPlayerProperties();
        int level = props.GetInt(0x19u);
        long totalXp = props.GetInt64(1u);
        long unassignedXp = props.GetInt64(UnassignedXpPropertyId);
        var xp = ComputeLevelXp(level, totalXp);

        int skillCredits = props.GetInt(0x18u);

        return new CharacterSheet
        {
            Name = CharacterName(),
            Level = level,
            Gender = CharacterIdentityText.GenderDisplayName(
                props.GetInt(CharacterIdentityText.GenderPropertyId)),
            Heritage = CharacterIdentityText.HeritageGroupDisplayName(
                props.GetInt(CharacterIdentityText.HeritageGroupPropertyId)),
            PkStatus = PkStatusText(props.GetInt(134u, 0)),
            TotalXp = totalXp,
            XpToNextLevel = xp.toNext,
            XpFraction = xp.fraction,

            HealthCurrent = VitalCurrent(LocalPlayerState.VitalKind.Health),
            HealthMax = VitalMax(LocalPlayerState.VitalKind.Health),
            StaminaCurrent = VitalCurrent(LocalPlayerState.VitalKind.Stamina),
            StaminaMax = VitalMax(LocalPlayerState.VitalKind.Stamina),
            ManaCurrent = VitalCurrent(LocalPlayerState.VitalKind.Mana),
            ManaMax = VitalMax(LocalPlayerState.VitalKind.Mana),

            Strength = AttrCurrent(LocalPlayerState.AttributeKind.Strength),
            Endurance = AttrCurrent(LocalPlayerState.AttributeKind.Endurance),
            Coordination = AttrCurrent(LocalPlayerState.AttributeKind.Coordination),
            Quickness = AttrCurrent(LocalPlayerState.AttributeKind.Quickness),
            Focus = AttrCurrent(LocalPlayerState.AttributeKind.Focus),
            Self = AttrCurrent(LocalPlayerState.AttributeKind.Self),

            UnspentSkillCredits = skillCredits,
            SpecializedSkillCredits = 0,
            ChessRank = props.GetInt(0xB5u),
            FishingSkill = props.GetInt(0xC0u),
            BirthTimestamp = props.Ints.TryGetValue(0x62u, out int born)
                ? born
                : null,
            TotalPlayTimeSeconds = props.Ints.TryGetValue(0x7Du, out int played)
                ? played
                : null,
            Deaths = props.GetInt(0x2Bu),
            SkillCredits = skillCredits,
            UnassignedXp = unassignedXp,
            AttributeRaiseCosts = BuildAttributeRaiseCosts(amount: 1),
            AttributeRaise10Costs = BuildAttributeRaiseCosts(amount: 10),
            Skills = BuildLiveCharacterSkills(),
            BurdenCurrent = props.GetInt(5u),
            BurdenMax = props.GetInt(96u),
            EncumbranceAugmentations = props.GetInt(0xE6u),
            CharacterInfoProperties = new Dictionary<uint, int>(props.Ints),
        };
    }

    private bool HasLiveData()
    {
        var props = CurrentPlayerProperties();
        return props.Ints.Count > 0
            || props.Int64s.Count > 0
            || _localPlayer.Skills.Count > 0
            || _localPlayer.GetAttribute(LocalPlayerState.AttributeKind.Strength) is not null
            || _localPlayer.Get(LocalPlayerState.VitalKind.Health) is not null;
    }

    /// <summary>The player's canonical bundle: the live ClientObject's when the
    /// player object has arrived (CreateObject merge-upsert), else the
    /// PlayerDescription snapshot on LocalPlayerState.</summary>
    private PropertyBundle CurrentPlayerProperties()
    {
        uint guid = _playerGuid();
        return guid != 0u && _objects.Get(guid) is { } player
            ? player.Properties
            : _localPlayer.Properties;
    }

    /// <summary>
    /// Load the portal ExperienceTable (0x0E000018), falling back to a
    /// type scan for older or odd dat collections. Failures are logged —
    /// never silently swallowed — and leave raise costs unavailable (0).
    /// </summary>
    public static DatReaderWriter.DBObjs.ExperienceTable? LoadExperienceTable(
        IDatReaderWriter dats, Action<string>? log = null)
    {
        if (dats is null) return null;

        try
        {
            var table = dats.Get<DatReaderWriter.DBObjs.ExperienceTable>(0x0E000018u);
            if (table is not null) return table;
        }
        catch (Exception ex)
        {
            log?.Invoke($"[D.2b-C] ExperienceTable 0x0E000018 read failed ({ex.GetType().Name}: {ex.Message}); trying type scan.");
        }

        try
        {
            foreach (uint id in dats.GetAllIdsOfType<DatReaderWriter.DBObjs.ExperienceTable>())
            {
                var table = dats.Get<DatReaderWriter.DBObjs.ExperienceTable>(id);
                if (table is not null) return table;
            }
        }
        catch (Exception ex)
        {
            log?.Invoke($"[D.2b-C] ExperienceTable type scan failed ({ex.GetType().Name}: {ex.Message}); raise costs unavailable.");
        }

        return null;
    }

    /// <summary>XP still needed for the next level + fill fraction of the
    /// current level band (retail (cur−base)/(cap−base); CharacterSheet.XpFraction).</summary>
    private (long toNext, float fraction) ComputeLevelXp(int level, long totalXp)
    {
        var levels = ExperienceTable?.Levels;
        if (levels is null || level < 0 || level + 1 >= levels.Length)
            return (0L, 0f);

        long current = ClampToLong(levels[level]);
        long next = ClampToLong(levels[level + 1]);
        if (next <= current) return (0L, 0f);

        long clampedXp = totalXp < current ? current : totalXp > next ? next : totalXp;
        long toNext = next - clampedXp;
        float fraction = (float)(clampedXp - current) / (next - current);
        return (toNext, fraction);
    }

    /// <summary>Per-attribute/vital raise costs in retail display order
    /// (see CharacterSheet.AttributeRaiseCosts). Cost 0 = maxed / unknown.</summary>
    private long[] BuildAttributeRaiseCosts(int amount)
    {
        var xp = ExperienceTable;
        return new[]
        {
            AttributeRaiseCost(LocalPlayerState.AttributeKind.Strength),
            AttributeRaiseCost(LocalPlayerState.AttributeKind.Endurance),
            AttributeRaiseCost(LocalPlayerState.AttributeKind.Coordination),
            AttributeRaiseCost(LocalPlayerState.AttributeKind.Quickness),
            AttributeRaiseCost(LocalPlayerState.AttributeKind.Focus),
            AttributeRaiseCost(LocalPlayerState.AttributeKind.Self),
            VitalRaiseCost(LocalPlayerState.VitalKind.Health),
            VitalRaiseCost(LocalPlayerState.VitalKind.Stamina),
            VitalRaiseCost(LocalPlayerState.VitalKind.Mana),
        };

        long AttributeRaiseCost(LocalPlayerState.AttributeKind kind)
        {
            var attr = _localPlayer.GetAttribute(kind);
            return attr is null || xp is null ? 0L : RaiseCostFromXpCurve(xp.Attributes, attr.Value.Ranks, attr.Value.Xp, amount);
        }

        long VitalRaiseCost(LocalPlayerState.VitalKind kind)
        {
            var vital = _localPlayer.Get(kind);
            return vital is null || xp is null ? 0L : RaiseCostFromXpCurve(xp.Vitals, vital.Value.Ranks, vital.Value.Xp, amount);
        }
    }

    private IReadOnlyList<CharacterSkill> BuildLiveCharacterSkills()
    {
        var result = new List<CharacterSkill>();
        var skillTable = SkillTable;
        var xp = ExperienceTable;

        foreach (var snapshot in _localPlayer.Skills.Values)
        {
            var advancement = AdvancementFromStatus(snapshot.Status);
            if (advancement == CharacterSkillAdvancementClass.Inactive)
                continue;

            DatReaderWriter.Types.SkillBase? skillBase = null;
            if (skillTable?.Skills is not null)
                skillTable.Skills.TryGetValue((DatReaderWriter.Enums.SkillId)snapshot.SkillId, out skillBase);

            string? name = skillBase?.Name.Value;
            if (string.IsNullOrWhiteSpace(name))
                name = $"Skill {snapshot.SkillId}";

            uint icon = skillBase?.IconId.DataId ?? 0u;
            int trainedCost = skillBase?.TrainedCost ?? 0;
            int specializedCost = skillBase?.SpecializedCost ?? 0;
            long raiseCost = SkillRaiseCost(xp, advancement, snapshot, 1);
            long raise10Cost = SkillRaiseCost(xp, advancement, snapshot, 10);

            result.Add(new CharacterSkill(
                snapshot.SkillId,
                name,
                icon,
                advancement,
                checked((int)Math.Min(int.MaxValue, snapshot.BaseLevel)),
                checked((int)Math.Min(int.MaxValue, snapshot.CurrentLevel)),
                IsUsableUntrained(snapshot.SkillId),
                trainedCost,
                specializedCost,
                raiseCost,
                raise10Cost));
        }

        return result;
    }

    private static CharacterSkillAdvancementClass AdvancementFromStatus(uint status) => status switch
    {
        1u => CharacterSkillAdvancementClass.Untrained,
        2u => CharacterSkillAdvancementClass.Trained,
        3u => CharacterSkillAdvancementClass.Specialized,
        _ => CharacterSkillAdvancementClass.Inactive,
    };

    private static bool IsUsableUntrained(uint skillId) => skillId switch
    {
        18u or 37u or 38u or 39u or 40u => false,
        _ => true,
    };

    private static long SkillRaiseCost(
        DatReaderWriter.DBObjs.ExperienceTable? xp,
        CharacterSkillAdvancementClass advancement,
        LocalPlayerState.SkillSnapshot skill,
        int amount)
    {
        if (xp is null) return 0L;
        uint[] curve = advancement == CharacterSkillAdvancementClass.Specialized
            ? xp.SpecializedSkills
            : xp.TrainedSkills;
        return RaiseCostFromXpCurve(curve, skill.Ranks, skill.Xp, amount);
    }

    /// <summary>Cost to advance <paramref name="amount"/> ranks along a retail
    /// cumulative-XP curve: curve[target] − xpAlreadySpent, clamped at the
    /// curve end (retail GetCostToRaise/GetCostToRaise10 0x0049cb80/0x0049cc70).</summary>
    private static long RaiseCostFromXpCurve(uint[]? curve, uint ranks, uint spentXp, int amount)
    {
        if (curve is null || amount <= 0) return 0L;
        long maxIndex = curve.Length - 1L;
        if (maxIndex <= ranks) return 0L;
        long targetLong = Math.Min((long)ranks + amount, maxIndex);
        long targetXp = curve[(int)targetLong];
        long cost = targetXp - spentXp;
        return cost > 0 ? cost : 0L;
    }

    private static long ClampToLong(ulong value) =>
        value > long.MaxValue ? long.MaxValue : (long)value;

    private static string? PkStatusText(int status) => status switch
    {
        0x2 => "Non-Player Killer",
        0x4 => "Player Killer",
        0x40 => "Player Killer Lite",
        _ => null,
    };

    private int AttrCurrent(LocalPlayerState.AttributeKind kind) =>
        _localPlayer.GetAttribute(kind) is { } attr ? checked((int)Math.Min(int.MaxValue, attr.Current)) : 0;

    private int VitalCurrent(LocalPlayerState.VitalKind kind) =>
        _localPlayer.Get(kind) is { } vital ? checked((int)Math.Min(int.MaxValue, vital.Current)) : 0;

    private int VitalMax(LocalPlayerState.VitalKind kind) =>
        _localPlayer.GetMaxApprox(kind) is { } max ? checked((int)Math.Min(int.MaxValue, max)) : 0;

    // ── Raise-request flow ─────────────────────────────────────────────────

    /// <summary>
    /// Send a raise/train action to the server and, when a send delegate
    /// fired, optimistically apply the local effect so the sheet stays
    /// current during the round trip. The next server snapshot remains
    /// authoritative (a rejected raise is corrected by the property echo —
    /// pending/rollback ledger tracked as a follow-up issue).
    /// </summary>
    public void HandleRaiseRequest(CharacterStatController.RaiseRequest request)
    {
        if (request.Cost <= 0) return;
        if (_canSendRaise is not null && !_canSendRaise()) return;

        bool sent = false;
        switch (request.Kind)
        {
            case CharacterStatController.RaiseTargetKind.Attribute:
                if (_sendRaiseAttribute is not null)
                {
                    _sendRaiseAttribute(request.StatId, (ulong)request.Cost);
                    sent = true;
                }
                break;
            case CharacterStatController.RaiseTargetKind.Vital:
                if (_sendRaiseVital is not null)
                {
                    _sendRaiseVital(request.StatId, (ulong)request.Cost);
                    sent = true;
                }
                break;
            case CharacterStatController.RaiseTargetKind.Skill:
                if (_sendRaiseSkill is not null)
                {
                    _sendRaiseSkill(request.StatId, (ulong)request.Cost);
                    sent = true;
                }
                break;
            case CharacterStatController.RaiseTargetKind.TrainSkill:
                if (_sendTrainSkill is not null && request.Cost <= uint.MaxValue)
                {
                    _sendTrainSkill(request.StatId, (uint)request.Cost);
                    sent = true;
                }
                break;
        }

        if (sent)
            ApplyLocalRaise(request);
    }

    private void ApplyLocalRaise(CharacterStatController.RaiseRequest request)
    {
        uint amount = request.Amount <= 0 ? 1u : (uint)request.Amount;
        ulong cost = (ulong)request.Cost;

        switch (request.Kind)
        {
            case CharacterStatController.RaiseTargetKind.Attribute:
                if (_localPlayer.ApplyAttributeRaise(request.StatId, amount, cost))
                    SpendUnassignedExperience(request.Cost);
                break;
            case CharacterStatController.RaiseTargetKind.Vital:
                if (_localPlayer.ApplyVitalRaise(request.StatId, amount, cost))
                    SpendUnassignedExperience(request.Cost);
                break;
            case CharacterStatController.RaiseTargetKind.Skill:
                if (_localPlayer.ApplySkillRaise(request.StatId, amount, cost))
                    SpendUnassignedExperience(request.Cost);
                break;
            case CharacterStatController.RaiseTargetKind.TrainSkill:
                if (_localPlayer.ApplySkillTraining(request.StatId))
                    SpendSkillCredits(request.Cost);
                break;
        }
    }

    private void SpendUnassignedExperience(long cost)
    {
        if (cost <= 0) return;
        uint guid = _playerGuid();
        if (guid != 0u && _objects.Get(guid) is { } player)
        {
            long current = player.Properties.GetInt64(UnassignedXpPropertyId);
            if (current <= 0) return;
            _objects.UpdateInt64Property(guid, UnassignedXpPropertyId,
                current > cost ? current - cost : 0L);
            return;
        }
        _localPlayer.DebitInt64Property(UnassignedXpPropertyId, cost);
    }

    private void SpendSkillCredits(long cost)
    {
        if (cost <= 0) return;
        int debit = cost > int.MaxValue ? int.MaxValue : (int)cost;
        uint guid = _playerGuid();
        if (guid != 0u && _objects.Get(guid) is { } player)
        {
            foreach (uint propertyId in SkillCreditPropertyIds)
            {
                if (!player.Properties.Ints.TryGetValue(propertyId, out int current))
                    continue;
                _objects.UpdateIntProperty(guid, propertyId,
                    current > debit ? current - debit : 0);
                return;
            }
            return;
        }
        foreach (uint propertyId in SkillCreditPropertyIds)
        {
            if (_localPlayer.DebitIntProperty(propertyId, debit))
                return;
        }
    }
}