using System.Globalization;
using System.Text.RegularExpressions;
using AcDream.App.Rendering;

namespace AcDream.App.Tests.Rendering.Walk;

/// <summary>
/// S4-c1 fix round 1, F3: parser for the OH alpha/depth captures
/// (docs/research/2026-09-01-overhaul/oh-capture/*.alphadepth.log —
/// tools/walk-oracle/oh/oh-capture-alpha-depth.cdb.template documents the
/// line formats). Reads the two lines this round's gate cares about:
///
/// <list type="bullet">
/// <item><c>PM poly=&lt;ptr&gt; mode=&lt;0|1&gt; counterBefore=&lt;hex&gt;</c> —
/// one per <c>D3DPolyRender::DrawPortalPolyInternal</c> @0x0059bc90 ENTRY
/// (mode 1 = far-Z building punch, mode 0 = true-depth exit seal). The
/// breakpoint is at function ENTRY, before the boundary guard runs inside
/// the function — a PM line is emitted for every ATTEMPT, guard-rejected
/// or not; <c>counterBefore</c> is the persistent
/// <c>portalsDrawnCount</c> global sampled before THIS call's own possible
/// increment.</item>
/// <item><c>PC ov=&lt;n&gt; counter=&lt;hex&gt; fc=&lt;0|1&gt;</c> — one per
/// <c>PView::DrawCells</c> @0x005a4840 ENTRY (root turn AND every building
/// look-in's own re-entrant call alike — the breakpoint doesn't
/// distinguish). <c>counter</c> is <c>portalsDrawnCount</c> sampled at
/// THIS call's entry, before its own possible read-then-zero.</item>
/// </list>
///
/// Frame delimiting mirrors <see cref="WalkOracleTrace"/> exactly (same
/// <c>F &lt;n&gt;</c> marker, same "events between F_n and F_(n+1) belong to
/// frame n" rule, same final-frame drop) so a caller can parse the SAME
/// capture file with both parsers and get position-consistent frame
/// numbering — <see cref="WalkOracleTrace"/> for the pose, this type for
/// the PM/PC sequences.
/// </summary>
public static class WalkAlphaDepthTrace
{
    public static IReadOnlyList<WalkAlphaDepthFrame> Parse(IEnumerable<string> lines)
    {
        var frames = new List<WalkAlphaDepthFrame>();
        List<(int Mode, int CounterBefore)>? currentPm = null;
        List<(int Ov, int Counter, int ForceClear)>? currentPc = null;
        List<(bool IsClip, bool IsNew)>? currentAm = null;
        List<(uint ThreshBits, string Ret, int AmCountAtThisPoint)>? currentFl = null;
        int currentNumber = 0;

        foreach (string line in lines)
        {
            Match frameMatch = FramePattern.Match(line);
            if (frameMatch.Success)
            {
                if (currentPm is not null)
                {
                    frames.Add(new WalkAlphaDepthFrame(
                        currentNumber, currentPm, currentPc!, currentAm!, currentFl!));
                }
                currentNumber = int.Parse(
                    frameMatch.Groups[1].Value, CultureInfo.InvariantCulture);
                currentPm = new List<(int, int)>();
                currentPc = new List<(int, int, int)>();
                currentAm = new List<(bool, bool)>();
                currentFl = new List<(uint, string, int)>();
                continue;
            }
            if (currentPm is null)
                continue;

            Match pm = PmPattern.Match(line);
            if (pm.Success)
            {
                currentPm.Add((
                    int.Parse(pm.Groups[1].Value, CultureInfo.InvariantCulture),
                    int.Parse(pm.Groups[2].Value, NumberStyles.HexNumber, CultureInfo.InvariantCulture)));
                continue;
            }
            Match pc = PcPattern.Match(line);
            if (pc.Success)
            {
                currentPc!.Add((
                    int.Parse(pc.Groups[1].Value, CultureInfo.InvariantCulture),
                    int.Parse(pc.Groups[2].Value, NumberStyles.HexNumber, CultureInfo.InvariantCulture),
                    int.Parse(pc.Groups[3].Value, CultureInfo.InvariantCulture)));
                continue;
            }
            // S4-c2: AM mesh=<ptr> surf=<n> csurf=<ptr> new=<0|1> clip=<0|1>
            // listSel=<0|1> — D3DPolyRender::AddMeshToAlphaList @0x0059c230's
            // own printf. listSel nonzero selects CLIP
            // (alphaedMeshCountClip/List); zero selects ALPHA
            // (alphaedMeshCountAlpha/List) — Ghidra-verified 2026-09-04, see
            // RetailAlphaList's own doc comment. "new" is the per-entry
            // first-for-list flag (param_4); "clip" (param_5, unused here)
            // is overrideClipmap.
            Match am = AmPattern.Match(line);
            if (am.Success)
            {
                currentAm!.Add((
                    IsClip: am.Groups["listSel"].Value != "0",
                    IsNew: am.Groups["new"].Value != "0"));
                continue;
            }
            // S4-c2: FL thresh=<hex float bits> ret=<return address> —
            // D3DPolyRender::FlushAlphaList @0x0059d2e0's own printf. `ret`
            // is the CALLER's return address (the call instruction's own
            // address + 5, x86 CALL rel32 being 5 bytes) — NOT the call
            // instruction's address itself.
            Match fl = FlPattern.Match(line);
            if (fl.Success)
            {
                currentFl!.Add((
                    uint.Parse(
                        fl.Groups["thresh"].Value, NumberStyles.HexNumber, CultureInfo.InvariantCulture),
                    fl.Groups["ret"].Value,
                    currentAm!.Count));
                continue;
            }
            // Anything else (PM/PC/FL/AM already handled; cdb chrome) is out
            // of this parser's scope — ignored, matching WalkOracleTrace's
            // own catch-all.
        }

        // The last STARTED frame is deliberately never appended — the
        // truncated detach frame, same rule as WalkOracleTrace.
        return frames;
    }

    /// <summary>
    /// S4-c2 gate G-c2: reconstructs retail's own sequence of ACTUAL flush
    /// drains (site, threshold, drained-CLIP-count, drained-ALPHA-count)
    /// purely from the capture's AM/FL text — no execution needed on this
    /// side. Mirrors <c>D3DPolyRender::FlushAlphaList</c>'s exact no-op rule
    /// (Ghidra-verified 2026-09-04: no-op only when BOTH running counts are
    /// strictly below <c>threshold * 3000</c>) so a threshold that DOESN'T
    /// drain (the overwhelming majority of 0.75f valve calls at ordinary
    /// scene complexity) leaves the running counts untouched for the NEXT
    /// flush call to inherit — exactly retail's own accumulation behavior.
    /// </summary>
    internal static IReadOnlyList<(RetailAlphaFlushSite Site, float Threshold, int DrainedClip, int DrainedAlpha)>
        BuildExpectedFlushTranscript(WalkAlphaDepthFrame frame)
    {
        var result = new List<(RetailAlphaFlushSite, float, int, int)>();
        int runningClip = 0;
        int runningAlpha = 0;
        int lastAmCount = 0;

        foreach ((uint threshBits, string ret, int amCountAtThisPoint) in frame.FlEvents)
        {
            // AM lines recorded (in interleaved parse order) between the
            // previous FL and this one accumulate onto the running counts —
            // exactly retail's own accumulation, since a no-op FlushAlphaList
            // leaves both counters untouched for the next call to inherit.
            for (int i = lastAmCount; i < amCountAtThisPoint; i++)
            {
                if (frame.AmEvents[i].IsClip)
                    runningClip++;
                else
                    runningAlpha++;
            }
            lastAmCount = amCountAtThisPoint;

            float threshold = BitConverter.UInt32BitsToSingle(threshBits);
            bool noOp = runningClip < threshold * 3000f && runningAlpha < threshold * 3000f;
            if (!noOp)
            {
                result.Add((MapSite(ret), threshold, runningClip, runningAlpha));
                runningClip = 0;
                runningAlpha = 0;
            }
        }

        return result;
    }

    private static RetailAlphaFlushSite MapSite(string ret) => ret switch
    {
        "0059f310" => RetailAlphaFlushSite.DrawBuilding,
        "005a1a0c" => RetailAlphaFlushSite.SortCellExit,
        "005a4877" => RetailAlphaFlushSite.LandscapeFlush,
        "00453b90" => RetailAlphaFlushSite.RenderNormalMode,
        _ => throw new InvalidOperationException(
            $"FL return address 0x{ret} is not one of the four normal-world flush sites "
            + "(OH1 contract §7) — the fifth private CreatureMode::Render caller, or an "
            + "unexpected address, reached this capture."),
    };

    public static IReadOnlyList<WalkAlphaDepthFrame> Load(string root, string fixtureName)
    {
        return Parse(File.ReadLines(ResolvePath(root, fixtureName)));
    }

    /// <summary>S4-c1 fix round 2 (R2-2): retail's <c>portalsDrawnCount</c>
    /// (wo(008719b4)) is a PERSISTENT session global carried by the running
    /// client across every captured frame, so each capture's own FIRST PM or
    /// PC line — wherever it falls, including the "F 1" preamble text a cdb
    /// session prints before the first parsed frame marker (terrace-edge and
    /// holtburg-doorway-still both have their first sample there) — already
    /// carries the value a real session would have accumulated before the
    /// capture began. Scans <paramref name="fixtureName"/>'s raw lines,
    /// ignoring frame boundaries entirely, for the first line matching
    /// either <see cref="PmPattern"/> or <see cref="PcPattern"/> and returns
    /// its counter field.</summary>
    public static int LoadInitialCounter(string root, string fixtureName)
    {
        foreach (string line in File.ReadLines(ResolvePath(root, fixtureName)))
        {
            Match pm = PmPattern.Match(line);
            if (pm.Success)
                return int.Parse(pm.Groups[2].Value, NumberStyles.HexNumber, CultureInfo.InvariantCulture);
            Match pc = PcPattern.Match(line);
            if (pc.Success)
                return int.Parse(pc.Groups[2].Value, NumberStyles.HexNumber, CultureInfo.InvariantCulture);
        }
        throw new InvalidOperationException(
            $"{fixtureName}: no PM/PC line found to seed PortalsDrawnCount from.");
    }

    private static string ResolvePath(string root, string fixtureName)
    {
        string repoRoot = FindRepositoryRoot();
        return Path.Combine(repoRoot, Path.Combine(root.Split('/')), fixtureName + ".log");
    }

    private static string FindRepositoryRoot()
    {
        DirectoryInfo? dir = new(AppContext.BaseDirectory);
        while (dir is not null)
        {
            if (File.Exists(Path.Combine(dir.FullName, "AcDream.slnx")))
                return dir.FullName;
            dir = dir.Parent;
        }
        throw new InvalidOperationException(
            "AcDream.slnx not found above the test base directory; walk-oracle fixtures unavailable.");
    }

    private static readonly Regex FramePattern = new(@"^F (\d+)\s*$", RegexOptions.Compiled);
    private static readonly Regex PmPattern = new(
        @"^PM poly=[0-9a-f]+ mode=([01]) counterBefore=([0-9a-f]{4})\s*$", RegexOptions.Compiled);
    private static readonly Regex PcPattern = new(
        @"^PC ov=(\d+) counter=([0-9a-f]{4}) fc=([01])\s*$", RegexOptions.Compiled);
    private static readonly Regex AmPattern = new(
        @"^AM mesh=[0-9a-f]+ surf=-?\d+ csurf=[0-9a-f]+ new=(?<new>[01]) clip=(?<clip>[01]) "
        + @"listSel=(?<listSel>[01])\s*$",
        RegexOptions.Compiled);
    private static readonly Regex FlPattern = new(
        @"^FL thresh=(?<thresh>[0-9a-f]{8}) ret=(?<ret>[0-9a-f]{8})\s*$", RegexOptions.Compiled);
}

/// <summary>One capture frame's PM (mode, counterBefore), PC (ov, counter,
/// forceClear), AM (isClip, isNew), and FL (thresholdBits, returnAddress,
/// cumulativeAmCountAtThisPoint) sequences, in the exact order the retail
/// trace recorded them. Pointers/surface indices are intentionally not
/// carried — every S4 gate's own comparison ignores them.</summary>
public sealed record WalkAlphaDepthFrame(
    int Number,
    IReadOnlyList<(int Mode, int CounterBefore)> PmEvents,
    IReadOnlyList<(int Ov, int Counter, int ForceClear)> PcEvents,
    IReadOnlyList<(bool IsClip, bool IsNew)> AmEvents,
    IReadOnlyList<(uint ThreshBits, string Ret, int AmCountAtThisPoint)> FlEvents);