using System.Collections.Generic;
using System.Numerics;
using Dalamud.Bindings.ImGui;
using Dalamud.Game.Text.SeStringHandling.Payloads;
using Dalamud.Interface.Utility;
using Dalamud.Interface.Utility.Raii;
using HellionChat.Code;
using HellionChat.Themes;
using HellionChat.Util;
using Microsoft.Extensions.Logging;

namespace HellionChat.Ui.Components;

internal sealed class ChunkRenderer
{
    private readonly ThemeRegistry _themes;
    private readonly FontManager _fonts;
    private readonly ILogger<ChunkRenderer> _logger;
    private readonly GameFunctions.GameFunctions _gameFunctions;
    private readonly string _salt;

    public ChunkRenderer(
        ThemeRegistry themes,
        FontManager fonts,
        ILogger<ChunkRenderer> logger,
        GameFunctions.GameFunctions gameFunctions
    )
    {
        _themes = themes;
        _fonts = fonts;
        _logger = logger;
        _gameFunctions = gameFunctions;
        // Per-ctor random matches v1.5.6 ChatLogWindow behavior — hashed player
        // names change every plugin reload to avoid stable cross-session linkage.
        _salt = new Random().Next().ToString();

        // No call sites yet; logging here will likely come later.
        _ = _logger;
    }

    // render-observability: the formatted sender text the real draw
    // path actually produced (post-ForDisplay). A SelfTest reads this after
    // driving DrawChunks to prove the WorldSuffixMode/NameFormMode reformat
    // reached the real render entry — never the helper in isolation. null until
    // a sender span is reformatted for display.
    internal string? LastRenderedSenderText { get; private set; }

    public void DrawChunks(
        IReadOnlyList<Chunk> chunks,
        bool wrap = true,
        PayloadHandler? handler = null,
        float lineWidth = 0f
    )
    {
        // Render a copy with the sender name reformatted per the user's
        // display options. Skipped in screenshot mode so the name-anonymising
        // path in DrawChunk stays reliable (privacy wins). ForDisplay returns
        // the list unchanged when nothing applies, so non-sender lists and the
        // neutral default cost only a quick scan.
        if (!Plugin.Config.ScreenshotMode)
        {
            var displayed = SenderNameDisplay.ForDisplay(chunks);
            // ForDisplay only allocates a NEW list when it actually reformatted
            // a sender span (same reference on the neutral default / non-sender
            // lists). So this scan runs only when a sender name was reformatted
            // for display — zero overhead on the neutral-default hot path.
            if (!ReferenceEquals(displayed, chunks))
            {
                chunks = displayed;
                foreach (var c in chunks)
                {
                    if (c.Source == ChunkSource.Sender && c is TextChunk reformatted)
                    {
                        LastRenderedSenderText = reformatted.Content;
                        break;
                    }
                }
            }
        }

        using var style = ImRaii.PushStyle(ImGuiStyleVar.ItemSpacing, Vector2.Zero);

        for (var i = 0; i < chunks.Count; i++)
        {
            if (chunks[i] is TextChunk text && string.IsNullOrEmpty(text.Content))
                continue;

            DrawChunk(chunks[i], wrap, handler, lineWidth);

            if (i < chunks.Count - 1)
                ImGui.SameLine();
        }
    }

    private void DrawChunk(
        Chunk chunk,
        bool wrap = true,
        PayloadHandler? handler = null,
        float lineWidth = 0f
    )
    {
        if (chunk is IconChunk iconChunk)
        {
            DrawIcon(chunk, iconChunk, handler);
            return;
        }

        if (chunk is not TextChunk text)
            return;

        var colour = text.Foreground;
        if (colour == null && text.FallbackColour != null)
        {
            var type = text.FallbackColour.Value;
            colour = Plugin.Config.ChatColours.TryGetValue(type, out var col)
                ? col
                : type.DefaultColor();
        }

        var push = colour != null;
        var uColor = push ? ColourUtil.RgbaToAbgr(colour!.Value) : 0;
        using var pushedColor = ImRaii.PushColor(ImGuiCol.Text, uColor, push);

        var useCustomItalicFont = Plugin.Config.FontsEnabled && _fonts.ItalicFont != null;
        if (text.Italic)
            (useCustomItalicFont ? _fonts.ItalicFont! : _fonts.AxisItalic).Push();

        // Check for contains here as sometimes there are multiple
        // TextChunks with the same PlayerPayload but only one has the name.
        // E.g. party chat with cross world players adds extra chunks.
        //
        // Note: This has been null before, I'm guessing due to some issues with
        // other plugins. New TextChunks will now enforce empty string in ctor,
        // but old ones may still be null.
        // ReSharper disable once NullCoalescingConditionIsAlwaysNotNullAccordingToAPIContract
        var content = text.Content ?? "";
        if (Plugin.Config.ScreenshotMode)
        {
            if (chunk.Link is PlayerPayload playerPayload)
                content = HidePlayerInString(
                    content,
                    playerPayload.PlayerName,
                    playerPayload.World.RowId
                );
            else if (Plugin.PlayerState.IsLoaded)
                content = HidePlayerInString(
                    content,
                    Plugin.PlayerState.CharacterName,
                    Plugin.PlayerState.HomeWorld.RowId
                );
        }

        var defaultText = ColourUtil.RgbaToVector4(_themes.Active.Colors.TextPrimary);
        if (wrap)
        {
            ImGuiUtil.WrapText(content, chunk, handler, defaultText, lineWidth);
        }
        else
        {
            ImGui.TextUnformatted(content);
            ImGuiUtil.PostPayload(chunk, handler);
        }

        if (text.Italic)
            (useCustomItalicFont ? _fonts.ItalicFont! : _fonts.AxisItalic).Pop();
    }

    internal void DrawIcon(Chunk chunk, IconChunk icon, PayloadHandler? handler)
    {
        if (!IconUtil.GfdFileView.TryGetEntry((uint)icon.Icon, out var entry))
            return;

        var iconTexture = Plugin
            .TextureProvider.GetFromGame("common/font/fonticon_ps5.tex")
            .GetWrapOrDefault();
        if (iconTexture == null)
            return;

        var texSize = new Vector2(iconTexture.Width, iconTexture.Height);

        var sizeRatio = FontManager.GetFontSize() / entry.Height;
        var size = new Vector2(entry.Width, entry.Height) * sizeRatio * ImGuiHelpers.GlobalScale;

        var uv0 = new Vector2(entry.Left, entry.Top + 170) * 2 / texSize;
        var uv1 =
            new Vector2(entry.Left + entry.Width, entry.Top + entry.Height + 170) * 2 / texSize;

        ImGui.Image(iconTexture.Handle, size, uv0, uv1);
        ImGuiUtil.PostPayload(chunk, handler);
    }

    private string HidePlayerInString(string str, string playerName, uint worldId)
    {
        var expected = _gameFunctions.Chat.AbbreviatePlayerName(playerName);
        var hash = HashPlayer(playerName, worldId);
        return str.Replace(playerName, expected).Replace(expected, hash);
    }

    private string HashPlayer(string playerName, uint worldId)
    {
        var hashCode = $"{_salt}{playerName}{worldId}".GetHashCode();
        return $"Player {hashCode:X8}";
    }
}