using System.Diagnostics;
using System.Text;
using TinyTUI.Components;
using TinyTUI.Overlay;
using TinyTUI.Rendering;
using TinyTUI.Stdout;
using TinyTUI.Terminal.Images;
using TinyTUI.Text;

namespace TinyTUI.Benchmarks;

internal static class Program
{
    private const int Width = 100;
    private const int Rows = 28;

    private static readonly TerminalSize Size = new(Width, Rows);

    private static int Main()
    {
        Console.OutputEncoding = Encoding.UTF8;

        var scenarios = new[]
        {
            RunLargeTextMeasureAndTruncate(),
            RunMarkdownRender(),
            RunOverlayCompose(),
            RunDifferentialRefresh(),
            RunImageLineGuard(),
        };

        Console.WriteLine("TinyTUI benchmark pressure scenarios");
        Console.WriteLine($"runtime: {Environment.Version}");
        Console.WriteLine($"size: {Width}x{Rows}");
        Console.WriteLine();

        foreach (var scenario in scenarios)
            Console.WriteLine(scenario);

        return scenarios.Any(static scenario => scenario.Failed) ? 1 : 0;
    }

    /// <summary>
    /// 压测 ANSI 宽度测量和截断路径
    /// </summary>
    private static ScenarioResult RunLargeTextMeasureAndTruncate()
    {
        var measurer = new TerminalTextMeasurer();
        var lines = BuildLargeTextLines(lineCount: 2_000);
        var totalWidth = 0;
        var truncatedWidth = 0;

        return Measure("large text measure/truncate", lines.Count, () =>
        {
            foreach (var line in lines)
            {
                totalWidth += measurer.GetWidth(line);
                truncatedWidth += measurer.GetWidth(measurer.Truncate(line, Width));
            }
        }, () => $"totalWidth={totalWidth}, truncatedWidth={truncatedWidth}");
    }

    /// <summary>
    /// 压测 Markdown 组件的轻量转换和宽度截断路径
    /// </summary>
    private static ScenarioResult RunMarkdownRender()
    {
        var markdown = new Markdown(BuildMarkdownDocument(sectionCount: 240));
        var renderedLineCount = 0;
        var checksum = 0;

        return Measure("markdown render", 60, () =>
        {
            for (var iteration = 0; iteration < 60; iteration++)
            {
                var lines = markdown.Render(Width);
                renderedLineCount = lines.Count;
                checksum += lines[iteration % lines.Count].Length;
            }
        }, () => $"lines={renderedLineCount}, checksum={checksum}");
    }

    /// <summary>
    /// 压测 overlay 合成中的按列切片和 reset 隔离路径
    /// </summary>
    private static ScenarioResult RunOverlayCompose()
    {
        var manager = new OverlayManager();
        var baseLines = BuildLargeTextLines(lineCount: Rows + 40);
        manager.Show(
            new StaticComponent(BuildOverlayLines()),
            new OverlayOptions
            {
                Anchor = OverlayAnchor.TopRight,
                Width = OverlaySize.Columns(42),
                MaxHeight = OverlaySize.Columns(10),
                Margin = new OverlayMargin(1),
            });

        var composedLineCount = 0;
        var sampleWidth = 0;

        return Measure("overlay compose", 800, () =>
        {
            for (var iteration = 0; iteration < 800; iteration++)
            {
                var composed = manager.Compose(baseLines, Size);
                composedLineCount = composed.Count;
                sampleWidth += composed[iteration % composed.Count].Length;
            }
        }, () => $"lines={composedLineCount}, sampledLength={sampleWidth}");
    }

    /// <summary>
    /// 压测差分渲染频繁刷新但只写内存输出
    /// </summary>
    private static ScenarioResult RunDifferentialRefresh()
    {
        var output = new MemoryTerminalOutput();
        var renderer = new DifferentialRenderer(
            output,
            new TerminalTextMeasurer(),
            new RenderPipelineOptions { UseSynchronizedOutput = false });
        var lines = BuildLargeTextLines(lineCount: Rows);

        return Measure("differential refresh", 1_000, () =>
        {
            for (var frame = 0; frame < 1_000; frame++)
            {
                lines[Rows / 2] = $"tick={frame:0000} Δ refresh path \e[36mchanged\e[39m";
                renderer.Render(lines, Size);
            }
        }, () => $"full={renderer.FullRedrawCount}, diff={renderer.DifferentialRedrawCount}, writes={output.WriteCount}, bytes={output.WrittenBytes}");
    }

    /// <summary>
    /// 压测图像行检测保护 避免大段协议内容进入普通测宽截断路径
    /// </summary>
    private static ScenarioResult RunImageLineGuard()
    {
        var output = new MemoryTerminalOutput();
        var renderer = new DifferentialRenderer(
            output,
            new TerminalTextMeasurer(),
            new RenderPipelineOptions
            {
                UseSynchronizedOutput = false,
                ThrowOnWidthOverflow = true,
            });
        var imageLine = BuildKittyImageLine();
        var guarded = false;
        var ids = 0;

        return Measure("image line guard", 120, () =>
        {
            for (var iteration = 0; iteration < 120; iteration++)
            {
                guarded |= TerminalImageService.IsImageLine(imageLine);
                ids += TerminalImageService.ExtractKittyImageIds(imageLine).Count();
                renderer.Render([$"frame={iteration}", imageLine, "after-image"], new TerminalSize(32, 6));
            }
        }, () => $"guarded={guarded}, extractedIds={ids}, bytes={output.WrittenBytes}");
    }

    /// <summary>
    /// 统一执行场景并把异常转换为可读输出
    /// </summary>
    private static ScenarioResult Measure(string name, int operations, Action action, Func<string> getDetails)
    {
        try
        {
            GC.Collect();
            GC.WaitForPendingFinalizers();
            GC.Collect();

            var before = GC.GetTotalAllocatedBytes(precise: true);
            var stopwatch = Stopwatch.StartNew();
            action();
            stopwatch.Stop();
            var allocated = GC.GetTotalAllocatedBytes(precise: true) - before;

            return ScenarioResult.Passed(name, operations, stopwatch.Elapsed, allocated, getDetails());
        }
        catch (Exception exception)
        {
            return ScenarioResult.FailedResult(name, exception);
        }
    }

    /// <summary>
    /// 构造混合 ANSI 中文 emoji 和 tab 的长文本输入
    /// </summary>
    private static List<string> BuildLargeTextLines(int lineCount)
    {
        var lines = new List<string>(lineCount);

        for (var index = 0; index < lineCount; index++)
        {
            // 混合不可见 ANSI 和宽字符 让测宽路径比 ASCII-only 更接近真实 TUI 输出
            lines.Add($"\e[3{index % 7 + 1}mrow-{index:0000}\e[39m\t中文列 {index % 11} emoji 😀 link \e]8;;https://example.local/{index}\aword-{index}\e]8;;\a trailing text");
        }

        return lines;
    }

    /// <summary>
    /// 构造重复 Markdown 文档用于观察轻量渲染成本
    /// </summary>
    private static string BuildMarkdownDocument(int sectionCount)
    {
        var builder = new StringBuilder();

        for (var section = 0; section < sectionCount; section++)
        {
            builder.AppendLine($"## Section {section}");
            builder.AppendLine("- **item** with `code` and 中文内容");
            builder.AppendLine("> quoted line with wide emoji 😀");
            builder.AppendLine("plain paragraph that should be truncated by the component renderer when the viewport is narrow");
        }

        return builder.ToString();
    }

    /// <summary>
    /// 构造 overlay 内容并包含 ANSI 样式用于观察 reset 隔离
    /// </summary>
    private static IReadOnlyList<string> BuildOverlayLines() =>
    [
        "\e[1mBenchmark Overlay\e[22m",
        "status: \e[32mrunning\e[39m",
        "wide: 中文 😀 boundary",
        "short",
        "long value should be clipped at the overlay boundary",
    ];

    /// <summary>
    /// 构造足够长的 Kitty 图像序列 模拟协议行保护场景
    /// </summary>
    private static string BuildKittyImageLine()
    {
        var payload = Convert.ToBase64String(Enumerable.Range(0, 24_000).Select(static value => (byte)(value % 251)).ToArray());
        return $"prefix \e_Ga=T,f=100,i=4242,q=2,c=20,r=8;{payload}\e\\ suffix";
    }
}

internal sealed record ScenarioResult(string Name, int Operations, TimeSpan Elapsed, long AllocatedBytes, string Details, Exception? Exception)
{
    public bool Failed => Exception is not null;

    public static ScenarioResult Passed(string name, int operations, TimeSpan elapsed, long allocatedBytes, string details) =>
        new(name, operations, elapsed, allocatedBytes, details, null);

    public static ScenarioResult FailedResult(string name, Exception exception) =>
        new(name, 0, TimeSpan.Zero, 0, string.Empty, exception);

    public override string ToString()
    {
        if (Exception is not null)
            return $"[fail] {Name}: {Exception.GetType().Name}: {Exception.Message}";

        var perOperation = Operations <= 0 ? 0 : Elapsed.TotalMilliseconds / Operations;
        return $"[pass] {Name}: {Operations} ops, {Elapsed.TotalMilliseconds:N1} ms, {perOperation:N3} ms/op, {AllocatedBytes / 1024.0:N1} KiB allocated, {Details}";
    }
}

internal sealed class StaticComponent(IReadOnlyList<string> lines) : IComponent
{
    public IReadOnlyList<string> Render(int width) => lines;
}

internal sealed class MemoryTerminalOutput : ITerminalOutput
{
    public int WriteCount { get; private set; }

    public long WrittenBytes { get; private set; }

    public void Write(string value)
    {
        WriteCount++;
        WrittenBytes += Encoding.UTF8.GetByteCount(value);
    }

    public void Flush()
    {
    }

    public void ClearScreen() => Write("\e[2J\e[H");

    public void HideCursor() => Write("\e[?25l");

    public void ShowCursor() => Write("\e[?25h");

    public void MoveCursorTo(int row, int column) => Write($"\e[{row};{column}H");
}