using System.Data;
using System.Globalization;
using System.Net.Http;
using System.Text;
using System.Text.Json;
using System.Text.RegularExpressions;

namespace Substation;

public record XToysPattern(string Name, List<WaveFrame> ChannelA, List<WaveFrame> ChannelB);

public static class XToysPatternImporter
{
    static readonly HttpClient Http = new();

    public static async Task<XToysPattern> ImportAsync(string url)
    {
        var patternId = ExtractPatternId(url);
        if (patternId == null)
            throw new ArgumentException("Could not extract pattern ID from URL. Expected format: https://xtoys.app/patterns/<ID>");

        var body = JsonSerializer.Serialize(new { data = new { patternID = patternId } });
        var content = new StringContent(body, Encoding.UTF8, "application/json");
        var response = await Http.PostAsync("https://xtoys.app/api/getPatternv2", content);
        response.EnsureSuccessStatusCode();

        var json = await response.Content.ReadAsStringAsync();
        return Parse(json);
    }

    static int FreqPctToMs(byte freqPct)
    {
        // xToys frequency: 0% = deep (1000ms), 100% = buzzy (10ms)
        return (int)Math.Round(1000 - 9.9 * freqPct);
    }

    static string? ExtractPatternId(string url)
    {
        var match = Regex.Match(url, @"/patterns/([A-Za-z0-9_-]+)");
        return match.Success ? match.Groups[1].Value : null;
    }

    static XToysPattern Parse(string json)
    {
        using var doc = JsonDocument.Parse(json);

        var pattern = doc.RootElement.GetProperty("result").GetProperty("pattern");
        var name = pattern.GetProperty("name").GetString() ?? "Unknown";
        var patternType = pattern.GetProperty("type").GetString() ?? "script-v3";
        var patternData = pattern.GetProperty("patternData");

        return patternType switch
        {
            "basic-v2"   => ParseBasicV2(name, patternData),
            "funscript"  => ParseFunscript(name, patternData),
            "draw"       => ParseFunscript(name, patternData),
            "audio"      => ParseAudio(name, pattern, patternData),
            "script-v3"  => ParseScriptV3(name, patternData),
            _            => ParseScriptV3(name, patternData)
        };
    }

    // ── script-v3: slider-driven, arbitrary pattern names, initialActions channel mapping ──

    static XToysPattern ParseScriptV3(string name, JsonElement patternData)
    {
        var sliders = ResolveSliders(patternData);
        bool hasFreq = patternData.TryGetProperty("frequencyControl", out var fc) && fc.GetBoolean();
        int channelCount = patternData.TryGetProperty("channels", out var cc) ? cc.GetInt32() : 2;

        // Parse initialActions to map pattern names → channels
        var patternToChannel = new Dictionary<string, int>();
        if (patternData.TryGetProperty("initialActions", out var actions))
        {
            foreach (var action in actions.EnumerateArray())
            {
                if (action.TryGetProperty("type", out var t) && t.GetString() == "updatePattern")
                {
                    var patName = action.GetProperty("pattern").GetString()!;
                    var channels = action.GetProperty("channels");
                    int ch = 1;
                    if (channels.TryGetProperty("1", out var c1) && c1.GetBoolean()) ch = 1;
                    else if (channels.TryGetProperty("2", out var c2) && c2.GetBoolean()) ch = 2;
                    patternToChannel[patName] = ch;
                }
            }
        }

        // Get all pattern names
        var patterns = patternData.GetProperty("patterns");
        var patternNames = new List<string>();
        foreach (var prop in patterns.EnumerateObject())
            patternNames.Add(prop.Name);

        // Classify patterns: frequency (name contains "freq") vs intensity
        var intPatterns = new List<(string name, int channel)>();
        var freqPatterns = new List<(string name, int channel)>();

        foreach (var pname in patternNames)
        {
            int ch = patternToChannel.GetValueOrDefault(pname, 1);
            if (hasFreq && pname.Contains("freq", StringComparison.OrdinalIgnoreCase))
                freqPatterns.Add((pname, ch));
            else
                intPatterns.Add((pname, ch));
        }

        // Evaluate patterns
        var intByChannel = new Dictionary<int, byte[]>();
        var freqByChannel = new Dictionary<int, byte[]>();

        foreach (var (pname, ch) in intPatterns)
            intByChannel[ch] = EvaluateLoops(patterns.GetProperty(pname), sliders);

        foreach (var (pname, ch) in freqPatterns)
            freqByChannel[ch] = EvaluateLoops(patterns.GetProperty(pname), sliders);

        // Get arrays for each channel (default to empty)
        var intA = intByChannel.GetValueOrDefault(1, Array.Empty<byte>());
        var intB = channelCount >= 2
            ? intByChannel.GetValueOrDefault(2, intA)
            : intA; // single channel → duplicate
        var freqA = freqByChannel.GetValueOrDefault(1, Array.Empty<byte>());
        var freqB = channelCount >= 2
            ? freqByChannel.GetValueOrDefault(2, freqA)
            : freqA;

        int tickCount = Math.Max(intA.Length, Math.Max(intB.Length, Math.Max(freqA.Length, freqB.Length)));
        if (tickCount == 0) tickCount = 1;

        byte defaultFreq = Freq.Compress(150);
        var channelA = new List<WaveFrame>(tickCount);
        var channelB = new List<WaveFrame>(tickCount);

        for (int i = 0; i < tickCount; i++)
        {
            byte ia = i < intA.Length ? intA[i] : (byte)0;
            byte ib = i < intB.Length ? intB[i] : (byte)0;
            byte fa = i < freqA.Length ? Freq.Compress(FreqPctToMs(freqA[i])) : defaultFreq;
            byte fb = i < freqB.Length ? Freq.Compress(FreqPctToMs(freqB[i])) : defaultFreq;

            channelA.Add(new WaveFrame(new[] { fa, fa, fa, fa }, new[] { ia, ia, ia, ia }));
            channelB.Add(new WaveFrame(new[] { fb, fb, fb, fb }, new[] { ib, ib, ib, ib }));
        }

        return new XToysPattern(name, channelA, channelB);
    }

    // ── basic-v2: channelData with loops/steps, optional frequencyControl ──

    static XToysPattern ParseBasicV2(string name, JsonElement patternData)
    {
        var emptySliders = new Dictionary<string, double>();
        const int defaultFreqMs = 150;
        bool hasFreq = patternData.TryGetProperty("frequencyControl", out var fc) && fc.GetBoolean();

        byte freqByte = Freq.Compress(defaultFreqMs);

        var intA = Array.Empty<byte>();
        var intB = Array.Empty<byte>();
        var freqA = Array.Empty<byte>();
        var freqB = Array.Empty<byte>();

        if (patternData.TryGetProperty("channelData", out var cd))
        {
            if (cd.TryGetProperty("1", out var ch1))
            {
                intA = EvaluateLoops(ch1, emptySliders);
                if (hasFreq) freqA = intA; // basic-v2 with freq: same data is freq
            }
            if (cd.TryGetProperty("2", out var ch2))
            {
                intB = EvaluateLoops(ch2, emptySliders);
                if (hasFreq) freqB = intB;
            }
        }

        // Single channel → duplicate
        if (intB.Length == 0 && intA.Length > 0)
        {
            intB = intA;
            freqB = freqA;
        }
        if (intA.Length == 0 && intB.Length > 0)
        {
            intA = intB;
            freqA = freqB;
        }

        int tickCount = Math.Max(intA.Length, intB.Length);
        if (tickCount == 0) tickCount = 1;

        var channelA = new List<WaveFrame>(tickCount);
        var channelB = new List<WaveFrame>(tickCount);

        for (int i = 0; i < tickCount; i++)
        {
            byte ia = i < intA.Length ? intA[i] : (byte)0;
            byte ib = i < intB.Length ? intB[i] : (byte)0;
            byte fa = hasFreq && i < freqA.Length ? Freq.Compress(FreqPctToMs(freqA[i])) : freqByte;
            byte fb = hasFreq && i < freqB.Length ? Freq.Compress(FreqPctToMs(freqB[i])) : freqByte;

            channelA.Add(new WaveFrame(new[] { fa, fa, fa, fa }, new[] { ia, ia, ia, ia }));
            channelB.Add(new WaveFrame(new[] { fb, fb, fb, fb }, new[] { ib, ib, ib, ib }));
        }

        return new XToysPattern(name, channelA, channelB);
    }

    // ── funscript / draw: {at, pos} timeline, resample to 100ms ticks ──

    static XToysPattern ParseFunscript(string name, JsonElement patternData)
    {
        byte freqByte = Freq.Compress(150);

        var intA = Array.Empty<byte>();
        var intB = Array.Empty<byte>();

        if (patternData.TryGetProperty("channelData", out var cd))
        {
            if (cd.TryGetProperty("1", out var ch1))
                intA = ResampleTimeline(ch1);
            if (cd.TryGetProperty("2", out var ch2))
                intB = ResampleTimeline(ch2);
        }

        // Single channel → duplicate
        if (intB.Length == 0 && intA.Length > 0) intB = intA;
        if (intA.Length == 0 && intB.Length > 0) intA = intB;

        int tickCount = Math.Max(intA.Length, intB.Length);
        if (tickCount == 0) tickCount = 1;

        var channelA = new List<WaveFrame>(tickCount);
        var channelB = new List<WaveFrame>(tickCount);

        for (int i = 0; i < tickCount; i++)
        {
            byte ia = i < intA.Length ? intA[i] : (byte)0;
            byte ib = i < intB.Length ? intB[i] : (byte)0;

            channelA.Add(new WaveFrame(new[] { freqByte, freqByte, freqByte, freqByte }, new[] { ia, ia, ia, ia }));
            channelB.Add(new WaveFrame(new[] { freqByte, freqByte, freqByte, freqByte }, new[] { ib, ib, ib, ib }));
        }

        return new XToysPattern(name, channelA, channelB);
    }

    static byte[] ResampleTimeline(JsonElement channelData)
    {
        // channelData is an array of {at, pos} objects (at in ms, pos 0-100)
        var points = new List<(double at, double pos)>();
        foreach (var pt in channelData.EnumerateArray())
        {
            double at = pt.GetProperty("at").GetDouble();
            double pos = pt.GetProperty("pos").GetDouble();
            points.Add((at, pos));
        }

        if (points.Count == 0) return Array.Empty<byte>();
        if (points.Count == 1) return new[] { (byte)Math.Clamp((int)Math.Round(points[0].pos), 0, 100) };

        double durationMs = points[^1].at;
        int tickCount = Math.Max(1, (int)Math.Ceiling(durationMs / 100.0));

        var result = new byte[tickCount];
        int ptIdx = 0;

        for (int t = 0; t < tickCount; t++)
        {
            double tickMs = t * 100.0;

            // Advance to the right pair of points
            while (ptIdx < points.Count - 2 && points[ptIdx + 1].at < tickMs)
                ptIdx++;

            // Linear interpolation between points[ptIdx] and points[ptIdx + 1]
            double pos;
            if (points[ptIdx + 1].at == points[ptIdx].at)
                pos = points[ptIdx].pos;
            else
            {
                double frac = (tickMs - points[ptIdx].at) / (points[ptIdx + 1].at - points[ptIdx].at);
                frac = Math.Clamp(frac, 0, 1);
                pos = points[ptIdx].pos + (points[ptIdx + 1].pos - points[ptIdx].pos) * frac;
            }

            result[t] = (byte)Math.Clamp((int)Math.Round(pos), 0, 100);
        }

        return result;
    }

    // ── audio: flat float array, resample to 100ms ticks ──

    static XToysPattern ParseAudio(string name, JsonElement pattern, JsonElement patternData)
    {
        byte freqByte = Freq.Compress(150);

        // Length is in seconds (from pattern.length or patternData.length)
        double lengthSec = 0;
        if (pattern.TryGetProperty("length", out var lenEl) && lenEl.ValueKind == JsonValueKind.Number)
            lengthSec = lenEl.GetDouble();
        else if (pattern.TryGetProperty("length", out var lenStr) && lenStr.ValueKind == JsonValueKind.String)
            double.TryParse(lenStr.GetString(), out lengthSec);

        double scale = patternData.TryGetProperty("scale", out var scaleEl) ? scaleEl.GetDouble() : 100;

        var intA = Array.Empty<byte>();
        var intB = Array.Empty<byte>();

        if (patternData.TryGetProperty("channelData", out var cd))
        {
            if (cd.TryGetProperty("1", out var ch1))
                intA = ResampleAudio(ch1, scale, lengthSec);
            if (cd.TryGetProperty("2", out var ch2))
                intB = ResampleAudio(ch2, scale, lengthSec);
        }

        // Single channel → duplicate
        if (intB.Length == 0 && intA.Length > 0) intB = intA;
        if (intA.Length == 0 && intB.Length > 0) intA = intB;

        int tickCount = Math.Max(intA.Length, intB.Length);
        if (tickCount == 0) tickCount = 1;

        var channelA = new List<WaveFrame>(tickCount);
        var channelB = new List<WaveFrame>(tickCount);

        for (int i = 0; i < tickCount; i++)
        {
            byte ia = i < intA.Length ? intA[i] : (byte)0;
            byte ib = i < intB.Length ? intB[i] : (byte)0;

            channelA.Add(new WaveFrame(new[] { freqByte, freqByte, freqByte, freqByte }, new[] { ia, ia, ia, ia }));
            channelB.Add(new WaveFrame(new[] { freqByte, freqByte, freqByte, freqByte }, new[] { ib, ib, ib, ib }));
        }

        return new XToysPattern(name, channelA, channelB);
    }

    static byte[] ResampleAudio(JsonElement channelData, double scale, double lengthSec)
    {
        // channelData is a flat array of float values (raw, need to divide by scale)
        var samples = new List<double>();
        foreach (var s in channelData.EnumerateArray())
            samples.Add(s.GetDouble() / scale * 100.0);

        if (samples.Count == 0) return Array.Empty<byte>();

        // Determine tick count from length (seconds → 100ms ticks)
        int tickCount;
        if (lengthSec > 0)
            tickCount = Math.Max(1, (int)Math.Ceiling(lengthSec * 10));
        else
            tickCount = samples.Count; // fallback: 1 sample per tick

        var result = new byte[tickCount];

        for (int t = 0; t < tickCount; t++)
        {
            // Map tick to sample index
            int idx = (int)Math.Round((double)t * samples.Count / tickCount);
            if (idx >= samples.Count) idx = samples.Count - 1;
            result[t] = (byte)Math.Clamp((int)Math.Round(samples[idx]), 0, 100);
        }

        return result;
    }

    // ── Shared helpers ──

    static Dictionary<string, double> ResolveSliders(JsonElement patternData)
    {
        var sliders = new Dictionary<string, double>();
        if (patternData.TryGetProperty("ma", out var ma))
        {
            foreach (var slider in ma.EnumerateArray())
            {
                var key = slider.GetProperty("key").GetString()!;
                var value = slider.GetProperty("value").GetDouble();
                sliders[key] = value;
            }
        }
        return sliders;
    }

    static byte[] EvaluateLoops(JsonElement loopsElement, Dictionary<string, double> sliders)
    {
        var values = new List<byte>();
        double lastEnd = 0;

        foreach (var loop in loopsElement.EnumerateArray())
        {
            var steps = loop.GetProperty("steps");
            foreach (var step in steps.EnumerateArray())
            {
                var type = step.GetProperty("type").GetString() ?? "straight";
                var time = EvaluateExpression(GetStepValue(step, "time"), sliders);
                var startVal = step.TryGetProperty("start", out var s)
                    ? (s.ValueKind == JsonValueKind.Null ? lastEnd : EvaluateExpression(GetStepValue(step, "start"), sliders))
                    : lastEnd;
                var endVal = EvaluateExpression(GetStepValue(step, "end"), sliders);

                int ticks = Math.Max(1, (int)Math.Round(time / 0.1));

                for (int t = 0; t < ticks; t++)
                {
                    double frac = (double)t / ticks;
                    double v;
                    if (type == "sine")
                        v = startVal + (endVal - startVal) * (1 - Math.Cos(frac * Math.PI)) / 2;
                    else
                        v = startVal + (endVal - startVal) * frac;

                    values.Add((byte)Math.Clamp((int)Math.Round(v), 0, 100));
                }

                lastEnd = endVal;
            }
        }

        return values.ToArray();
    }

    static string GetStepValue(JsonElement step, string propName)
    {
        if (!step.TryGetProperty(propName, out var el))
            return "0";
        return el.ValueKind switch
        {
            JsonValueKind.String => el.GetString() ?? "0",
            JsonValueKind.Number => el.GetDouble().ToString(CultureInfo.InvariantCulture),
            _ => "0"
        };
    }

    static double EvaluateExpression(string expr, Dictionary<string, double> sliders)
    {
        // Replace {var} references with slider values
        var resolved = Regex.Replace(expr, @"\{(\w+)\}", m =>
            sliders.TryGetValue(m.Groups[1].Value, out var val)
                ? val.ToString(CultureInfo.InvariantCulture)
                : "0");

        // Try plain number first
        if (double.TryParse(resolved, CultureInfo.InvariantCulture, out var simple))
            return simple;

        // Pre-process pow(a, b) calls — DataTable.Compute doesn't support pow
        resolved = Regex.Replace(resolved, @"pow\(\s*([-\d.]+)\s*,\s*([-\d.]+)\s*\)", m =>
        {
            double a = double.Parse(m.Groups[1].Value, CultureInfo.InvariantCulture);
            double b = double.Parse(m.Groups[2].Value, CultureInfo.InvariantCulture);
            return Math.Pow(a, b).ToString("G15", CultureInfo.InvariantCulture);
        });

        // Evaluate with DataTable.Compute (handles +, -, *, /, parentheses)
        try
        {
            var result = new DataTable().Compute(resolved, null);
            return Convert.ToDouble(result, CultureInfo.InvariantCulture);
        }
        catch
        {
            // Fallback: try simple number
            return double.TryParse(resolved, CultureInfo.InvariantCulture, out var fallback) ? fallback : 0;
        }
    }
}