using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;
using System.Text.Json.Nodes;
using System.Text.RegularExpressions;
using Tesseract;
using XFEWorkflow.Abstractions;

namespace XFEWorkflow.Plugins.Vision;

public sealed class OcrRecognizer : IDisposable
{
    private static readonly object nativeGate = new();
    private static bool nativeLoaded;
    private readonly TesseractEngine engine;
    public OcrRecognizer(string language = "chi_sim+eng")
    {
        if (RuntimeInformation.ProcessArchitecture is not (Architecture.X64 or Architecture.X86))
            throw new PlatformNotSupportedException("当前离线 OCR 引擎支持 Windows x64/x86；请使用 x64 客户端进行文字识别。");
        if (language is not ("chi_sim+eng" or "chi_sim" or "eng")) throw new ArgumentException("识别语言应为 chi_sim+eng、chi_sim 或 eng。");
        var root = Path.GetDirectoryName(typeof(OcrRecognizer).Assembly.Location)!;
        foreach (var code in language.Split('+'))
            if (!File.Exists(Path.Combine(root, "tessdata", code + ".traineddata"))) throw new FileNotFoundException("OCR 模型缺失，请重新安装屏幕与识别插件：" + code);
        TesseractEnviornment.CustomSearchPath = root;
        try
        {
            lock (nativeGate)
            {
                if (!nativeLoaded)
                {
                    var runtime = Path.Combine(root, "NativeRuntime", RuntimeInformation.ProcessArchitecture == Architecture.X64 ? "win-x64" : "win-x86");
                    foreach (var file in new[] { "vcruntime140.dll", "vcruntime140_1.dll", "msvcp140.dll" })
                        if (File.Exists(Path.Combine(runtime, file))) NativeLibrary.Load(Path.Combine(runtime, file));
                    nativeLoaded = true;
                }
            }
            engine = new TesseractEngine(Path.Combine(root, "tessdata"), language, EngineMode.LstmOnly);
        }
        catch (Exception ex) when (ex is DllNotFoundException or TypeInitializationException)
        { throw new InvalidOperationException("无法加载离线 OCR 引擎，请检查插件原生库与 Microsoft Visual C++ 2015–2022 运行库。", ex); }
    }
    public JsonObject Recognize(ScreenFrame frame, JsonObject options, CancellationToken ct)
    {
        ct.ThrowIfCancellationRequested();
        var scale = VisionParameters.Number(options, "scale", 2, 1, 4);
        var confidence = VisionParameters.Number(options, "minimumConfidence", 35, 0, 100);
        var segmentation = options.String("segmentation", "SparseText") switch
        {
            "SparseText" => PageSegMode.SparseText, "Auto" => PageSegMode.Auto,
            "SingleBlock" => PageSegMode.SingleBlock, "SingleLine" => PageSegMode.SingleLine,
            _ => throw new ArgumentException("文字排版参数无效。")
        };
        var width = checked((int)Math.Round(frame.Bitmap.Width * scale));
        var height = checked((int)Math.Round(frame.Bitmap.Height * scale));
        if ((long)width * height > ScreenRegion.MaximumPixels) throw new ArgumentException("放大后的 OCR 图像超过 4000 万像素，请缩小区域或降低放大倍数。");
        using var resized = new Bitmap(width, height, PixelFormat.Format24bppRgb);
        using (var graphics = Graphics.FromImage(resized))
        {
            graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
            graphics.Clear(Color.White); graphics.DrawImage(frame.Bitmap, 0, 0, width, height);
        }
        using var stream = new MemoryStream(); resized.Save(stream, System.Drawing.Imaging.ImageFormat.Png);
        using var pix = Pix.LoadFromMemory(stream.ToArray());
        using var page = engine.Process(pix, segmentation);
        ct.ThrowIfCancellationRequested();
        JsonArray words = [], lines = [];
        using (var iterator = page.GetIterator())
        {
            iterator.Begin(); var line = -1;
            do
            {
                ct.ThrowIfCancellationRequested();
                if (line < 0 || iterator.IsAtBeginningOf(PageIteratorLevel.TextLine))
                {
                    line++;
                    if (iterator.TryGetBoundingBox(PageIteratorLevel.TextLine, out var lineBounds))
                    {
                        var entry = Bounds(lineBounds, frame.Region, scale);
                        entry["text"] = (iterator.GetText(PageIteratorLevel.TextLine) ?? "").Trim(); entry["line"] = line;
                        lines.Add(entry);
                    }
                }
                var text = (iterator.GetText(PageIteratorLevel.Word) ?? "").Trim();
                var score = iterator.GetConfidence(PageIteratorLevel.Word);
                if (text.Length == 0 || score < confidence || !iterator.TryGetBoundingBox(PageIteratorLevel.Word, out var bounds)) continue;
                var word = Bounds(bounds, frame.Region, scale);
                word["text"] = text; word["confidence"] = Math.Round(score, 2); word["line"] = line; words.Add(word);
            } while (iterator.Next(PageIteratorLevel.Word));
        }
        return new() { ["text"] = page.GetText().Trim(), ["words"] = words, ["lines"] = lines,
            ["confidence"] = Math.Round(page.GetMeanConfidence() * 100, 2), ["coordinateSpace"] = frame.CoordinateSpace, ["region"] = frame.Region.ToJson() };
    }
    private static JsonObject Bounds(Tesseract.Rect bounds, ScreenRegion origin, double scale)
    {
        var x = (int)Math.Floor(bounds.X1 / scale); var y = (int)Math.Floor(bounds.Y1 / scale);
        return new ScreenRegion(origin.X + x, origin.Y + y, Math.Max(1, (int)Math.Ceiling(bounds.X2 / scale) - x), Math.Max(1, (int)Math.Ceiling(bounds.Y2 / scale) - y)).ToJson();
    }
    public void Dispose() => engine.Dispose();
}

public static class OcrTextSearch
{
    public static JsonObject Find(JsonObject recognized, string target, string mode = "contains", bool ignoreCase = true)
    {
        if (string.IsNullOrWhiteSpace(target)) throw new ArgumentException("请输入要查找的文字。");
        if (mode is not ("contains" or "exact" or "regex")) throw new ArgumentException("文字匹配方式无效。");
        var comparison = ignoreCase ? StringComparison.OrdinalIgnoreCase : StringComparison.Ordinal;
        var regex = mode == "regex" ? new Regex(target, ignoreCase ? RegexOptions.IgnoreCase | RegexOptions.CultureInvariant : RegexOptions.CultureInvariant, TimeSpan.FromMilliseconds(500)) : null;
        JsonArray matches = [];
        var groups = (recognized["words"] as JsonArray ?? []).OfType<JsonObject>().GroupBy(w => w.Integer("line"));
        foreach (var group in groups)
        {
            var words = group.ToArray();
            var text = string.Join(" ", words.Select(w => w.String("text")));
            var offsets = new List<(int Start, int End, JsonObject Word)>(); var position = 0;
            foreach (var word in words) { var wordText = word.String("text"); offsets.Add((position, position + wordText.Length, word)); position += wordText.Length + 1; }
            // Chinese OCR often inserts spaces between words. Match without whitespace,
            // while retaining a map to original characters for precise click bounds.
            var map = Enumerable.Range(0, text.Length).Where(i => !char.IsWhiteSpace(text[i])).ToArray();
            var compact = new string(map.Select(i => text[i]).ToArray());
            var needle = new string(target.Where(c => !char.IsWhiteSpace(c)).ToArray());
            var spans = new List<(int Start, int Length, bool Compact)>();
            if (regex is not null) { foreach (Match match in regex.Matches(text)) if (match.Length > 0) spans.Add((match.Index, match.Length, false)); }
            else if (mode == "exact") { if (compact.Equals(needle, comparison)) spans.Add((0, compact.Length, true)); }
            else for (var start = 0; needle.Length > 0 && start < compact.Length;)
            {
                var index = compact.IndexOf(needle, start, comparison); if (index < 0) break;
                spans.Add((index, needle.Length, true)); start = index + needle.Length;
            }
            foreach (var span in spans)
            {
                var start = span.Compact ? map[span.Start] : span.Start;
                var end = span.Compact ? map[span.Start + span.Length - 1] + 1 : span.Start + span.Length;
                var selected = offsets.Where(w => w.End > start && w.Start < end).Select(w => w.Word).ToArray();
                if (selected.Length == 0) continue;
                var x = selected.Min(w => w.Integer("x")); var y = selected.Min(w => w.Integer("y"));
                var right = selected.Max(w => w.Integer("x") + w.Integer("width")); var bottom = selected.Max(w => w.Integer("y") + w.Integer("height"));
                var bounds = new ScreenRegion(x, y, right - x, bottom - y);
                var match = bounds.ToJson(); match["text"] = text[start..end]; match["point"] = VisionParameters.Point(bounds.CenterX, bounds.CenterY); matches.Add(match);
                if (matches.Count >= 100) break;
            }
            if (matches.Count >= 100) break;
        }
        return VisionParameters.Matches(matches, recognized.String("coordinateSpace"), recognized.String("text"));
    }
}