using Dalamud.Bindings.ImGui;
using Dalamud.Interface.Utility;
using Dalamud.Interface.Utility.Raii;
using Dalamud.Utility;
using LightlessSync.LightlessConfiguration;
using LightlessSync.Services;
using LightlessSync.Services.Mediator;
using Microsoft.Extensions.Logging;
using System.IO;
using System.Numerics;
using System.Reflection;
using System.Text;
using YamlDotNet.Serialization;
using YamlDotNet.Serialization.NamingConventions;

namespace LightlessSync.UI;

public class UpdateNotesUi : WindowMediatorSubscriberBase
{
    private readonly LightlessConfigService _configService;
    private readonly UiSharedService _uiShared;

    private readonly List<string> _contributors = [];
    private readonly List<string> _credits = [];
    private readonly List<string> _supporters = [];

    private ChangelogFile _changelog = new();
    private bool _scrollToTop;
    private int _selectedTab;

    public UpdateNotesUi(ILogger<UpdateNotesUi> logger,
        LightlessMediator mediator,
        UiSharedService uiShared,
        LightlessConfigService configService,
        PerformanceCollectorService performanceCollectorService)
        : base(logger, mediator, "Lightless Sync — Update Notes", performanceCollectorService)
    {
        _configService = configService;
        _uiShared = uiShared;

        AllowClickthrough = false;
        AllowPinning = false;
        RespectCloseHotkey = true;
        ShowCloseButton = true;

        Flags = ImGuiWindowFlags.NoSavedSettings | ImGuiWindowFlags.NoResize | ImGuiWindowFlags.NoCollapse;

        SizeConstraints = new WindowSizeConstraints()
        {
            MinimumSize = new Vector2(600, 500),
            MaximumSize = new Vector2(900, 2000),
        };

        LoadEmbeddedResources();
    }

    public override void OnOpen()
    {
        _scrollToTop = true;
    }

    protected override void DrawInternal()
    {
        if (_uiShared.IsInGpose)
            return;

        DrawHeader();
        DrawLinkButtons();
        ImGuiHelpers.ScaledDummy(6);
        DrawTabs();
        DrawCloseButton();
    }

    private void DrawHeader()
    {
        using (_uiShared.UidFont.Push())
        {
            ImGui.TextUnformatted("Lightless Sync");
        }

        _uiShared.ColoredSeparator(UIColors.Get("LightlessBlue"), thickness: 2f);

        if (!string.IsNullOrEmpty(_changelog.Tagline))
        {
            _uiShared.MediumText(_changelog.Tagline, UIColors.Get("LightlessBlue"));
            if (!string.IsNullOrEmpty(_changelog.Subline))
            {
                ImGui.SameLine();
                ImGui.TextColored(new Vector4(.75f, .75f, .85f, 1f), $"  –  {_changelog.Subline}");
            }
        }

        ImGuiHelpers.ScaledDummy(5);
    }

    private void DrawLinkButtons()
    {
        var segmentSize = ImGui.GetWindowSize().X / 4.2f;
        var buttonSize = new Vector2(segmentSize, ImGui.GetTextLineHeight() * 1.6f);

        if (ImGui.Button("Discord", buttonSize))
            Util.OpenLink("https://discord.gg/dsbjcXMnhA");
        ImGui.SameLine();

        if (ImGui.Button("GitHub", buttonSize))
            Util.OpenLink("https://github.com/Light-Public-Syncshells/LightlessSync");
        ImGui.SameLine();

        if (ImGui.Button("Ko-fi", buttonSize))
            Util.OpenLink("https://ko-fi.com/lightlesssync");
        ImGui.SameLine();

        if (ImGui.Button("More Links", buttonSize))
            Util.OpenLink("https://lightless.link");
    }

    private void DrawCloseButton()
    {
        var closeWidth = 300f * ImGuiHelpers.GlobalScale;
        ImGui.SetCursorPosX((ImGui.GetWindowSize().X - closeWidth) / 2);
        if (ImGui.Button("Close", new Vector2(closeWidth, 0)))
        {
            IsOpen = false;
        }
    }

    private void DrawTabs()
    {
        using var tabBar = ImRaii.TabBar("lightless_update_tabs");
        if (!tabBar)
            return;

        using (var changelogTab = ImRaii.TabItem(" Changelog "))
        {
            if (changelogTab)
            {
                _selectedTab = 0;
                DrawChangelog();
            }
        }

        using (var creditsTab = ImRaii.TabItem(" Supporters & Credits "))
        {
            if (creditsTab)
            {
                _selectedTab = 1;
                DrawCredits();
            }
        }
    }

    private void DrawChangelog()
    {
        using var child = ImRaii.Child("###ll_changelog", new Vector2(0, ImGui.GetContentRegionAvail().Y - 44), false);
        if (!child)
            return;

        if (_scrollToTop)
        {
            _scrollToTop = false;
            ImGui.SetScrollHereY(0);
        }

        foreach (var entry in _changelog.Changelog)
            DrawChangelogEntry(entry);

        ImGui.Spacing();
    }

    private void DrawChangelogEntry(ChangelogEntry entry)
    {
        var currentColor = entry.IsCurrent == true
            ? new Vector4(0.5f, 0.9f, 0.5f, 1.0f)
            : new Vector4(0.75f, 0.75f, 0.85f, 1.0f);

        bool isOpen;
        using (ImRaii.PushColor(ImGuiCol.Text, currentColor))
        {
            isOpen = ImGui.CollapsingHeader($" {entry.Name} — {entry.Date} ");
        }

        ImGui.SameLine();
        ImGui.TextColored(new Vector4(0.75f, 0.75f, 0.85f, 1.0f), $"  —  {entry.Tagline}");

        if (!isOpen)
            return;

        ImGuiHelpers.ScaledDummy(5);

        if (!string.IsNullOrEmpty(entry.Message))
        {
            ImGui.TextWrapped(entry.Message);
            ImGuiHelpers.ScaledDummy(5);
            return;
        }

        if (entry.Versions != null)
        {
            foreach (var version in entry.Versions)
            {
                DrawFeatureHeader(version.Number, new Vector4(0.5f, 0.9f, 0.5f, 1.0f));
                foreach (var item in version.Items)
                    ImGui.BulletText(item);
            }
        }

        ImGuiHelpers.ScaledDummy(5);
    }

    private static void DrawFeatureHeader(string title, Vector4 accentColor)
    {
        var drawList = ImGui.GetWindowDrawList();
        var startPos = ImGui.GetCursorScreenPos();

        var backgroundMin = startPos + new Vector2(-10, -5);
        var backgroundMax = startPos + new Vector2(ImGui.GetContentRegionAvail().X + 10, 25);
        drawList.AddRectFilled(backgroundMin, backgroundMax, ImGui.GetColorU32(new Vector4(0.12f, 0.12f, 0.15f, 0.6f)), 4f);
        drawList.AddRectFilled(backgroundMin, backgroundMin + new Vector2(3, backgroundMax.Y - backgroundMin.Y), ImGui.GetColorU32(accentColor), 2f);

        ImGui.Spacing();
        ImGui.TextColored(accentColor, title);
        ImGui.Spacing();
    }

    private void DrawCredits()
    {
        ImGui.TextUnformatted("Maintained & Developed by the Lightless Sync team.");
        ImGui.TextUnformatted("Thank you to all supporters and contributors!");
        ImGuiHelpers.ScaledDummy(5);

        var availableRegion = ImGui.GetContentRegionAvail();
        var halfWidth = new Vector2(
            availableRegion.X / 2f - ImGui.GetStyle().ItemSpacing.X / 2f,
            availableRegion.Y - 120 * ImGuiHelpers.GlobalScale);

        using (var leftChild = ImRaii.Child("left_supporters", halfWidth))
        {
            if (leftChild)
            {
                ImGui.TextUnformatted("Supporters (Ko-fi / Patreon)");
                _uiShared.RoundedSeparator(UIColors.Get("LightlessBlue"), thickness: 2f);
                foreach (var supporter in _supporters)
                    ImGui.BulletText(supporter);
            }
        }

        ImGui.SameLine();

        using (var rightChild = ImRaii.Child("right_contributors", halfWidth))
        {
            if (rightChild)
            {
                ImGui.TextUnformatted("Contributors");
                _uiShared.RoundedSeparator(UIColors.Get("LightlessBlue"), thickness: 2f);
                foreach (var contributor in _contributors)
                    ImGui.BulletText(contributor);
            }
        }

        ImGuiHelpers.ScaledDummy(8);
        ImGui.TextUnformatted("Credits");
        _uiShared.RoundedSeparator(UIColors.Get("LightlessYellow"), thickness: 2f);
        foreach (var credit in _credits)
            ImGui.BulletText(credit);
    }

    private void LoadEmbeddedResources()
    {
        try
        {
            var assembly = Assembly.GetExecutingAssembly();

            ReadLines(assembly, "LightlessSync.UI.Changelog.supporters.txt", _supporters);
            ReadLines(assembly, "LightlessSync.UI.Changelog.contributors.txt", _contributors);
            ReadLines(assembly, "LightlessSync.UI.Changelog.credits.txt", _credits);

            using var changelogStream = assembly.GetManifestResourceStream("LightlessSync.UI.Changelog.changelog.yaml");
            if (changelogStream != null)
            {
                using var reader = new StreamReader(changelogStream, Encoding.UTF8, true, 128);
                var yaml = reader.ReadToEnd();
                var deserializer = new DeserializerBuilder()
                    .WithNamingConvention(CamelCaseNamingConvention.Instance)
                    .IgnoreUnmatchedProperties()
                    .Build();
                _changelog = deserializer.Deserialize<ChangelogFile>(yaml) ?? new();
            }
        }
        catch
        {
            // Ignore - window will gracefully render with defaults
        }
    }

    private static void ReadLines(Assembly assembly, string resourceName, List<string> target)
    {
        using var stream = assembly.GetManifestResourceStream(resourceName);
        if (stream == null)
            return;

        using var reader = new StreamReader(stream, Encoding.UTF8, true, 128);
        string? line;
        while ((line = reader.ReadLine()) != null)
        {
            if (!string.IsNullOrWhiteSpace(line))
                target.Add(line.Trim());
        }
    }

    private sealed record ChangelogFile
    {
        public string Tagline { get; init; } = string.Empty;
        public string Subline { get; init; } = string.Empty;
        public List<ChangelogEntry> Changelog { get; init; } = new();
    }

    private sealed record ChangelogEntry
    {
        public string Name { get; init; } = string.Empty;
        public string Date { get; init; } = string.Empty;
        public string Tagline { get; init; } = string.Empty;
        public bool? IsCurrent { get; init; }
        public string? Message { get; init; }
        public List<ChangelogVersion>? Versions { get; init; }
    }

    private sealed record ChangelogVersion
    {
        public string Number { get; init; } = string.Empty;
        public List<string> Items { get; init; } = new();
    }
}