using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Text;
using Dalamud;
using Dalamud.Game.Text.SeStringHandling;
using Dalamud.Game.Text.SeStringHandling.Payloads;
using Dalamud.Utility;
using Lumina.Excel;
using Lumina.Excel.GeneratedSheets;
using Pidgin;
using static Pidgin.Parser;
using static Pidgin.Parser<char>;
using TextPayload = Lumina.Text.Payloads.TextPayload;

namespace ChatTwo.Util;

internal static class AutoTranslate
{
    private static readonly Dictionary<ClientLanguage, List<AutoTranslateEntry>> Entries = new();
    private static readonly HashSet<(uint, uint)> ValidEntries = [];

    private static readonly ExcelSheet<Completion> CompletionSheet;

    static AutoTranslate()
    {
        CompletionSheet = Plugin.DataManager.GetExcelSheet<Completion>()!;
    }

    private static Parser<char, (string name, Maybe<IEnumerable<ISelectorPart>> selector)> Parser()
    {
        var sheetName = Any
            .AtLeastOnceUntil(Lookahead(Char('[').IgnoreResult().Or(End)))
            .Select(string.Concat)
            .Labelled("sheetName");
        var numPair = Map(
                (first, second) => (ISelectorPart) new IndexRange(
                    uint.Parse(string.Concat(first)),
                    uint.Parse(string.Concat(second))
                ),
                Digit.AtLeastOnce().Before(Char('-')),
                Digit.AtLeastOnce()
            )
            .Labelled("numPair");
        var singleRow = Digit
            .AtLeastOnce()
            .Select(string.Concat)
            .Select(num => (ISelectorPart) new SingleRow(uint.Parse(num)));
        var column = String("col-")
            .Then(Digit.AtLeastOnce())
            .Select(string.Concat)
            .Select(num => (ISelectorPart) new ColumnSpecifier(uint.Parse(num)));
        var noun = String("noun")
            .Select(_ => (ISelectorPart) new NounMarker());
        var selectorItems = OneOf(
                Try(numPair),
                singleRow,
                column,
                noun
            )
            .Separated(Char(','))
            .Labelled("selectorItems");
        var selector = selectorItems
            .Between(Char('['), Char(']'))
            .Labelled("selector");
        return Map(
            (name, sel) => (name, sel),
            sheetName,
            selector.Optional()
        );
    }

    private static string TextValue(this Lumina.Text.SeString str)
    {
        var payloads = str.Payloads
            .Select(p => {
                if (p is TextPayload text) {
                    return p.Data[0] == 0x03
                        ? text.RawString[1..]
                        : text.RawString;
                }

                if (p.Data.Length <= 1) {
                    return "";
                }

                if (p.Data[1] == 0x1F) {
                    return "-";
                }

                if (p.Data.Length > 2 && p.Data[1] == 0x20) {
                    var value = p.Data.Length > 4
                        ? p.Data[3] - 1
                        : p.Data[2];
                    return ((char) (48 + value)).ToString();
                }

                return "";
            });
        return string.Join("", payloads);
    }

    /// <summary>
    /// Preloads auto-translate entries into the cache for the current game
    /// language. Without this, the first message will take a long time to send
    /// (which causes a hitch in the main thread).
    ///
    /// This spawns a new thread.
    /// </summary>
    internal static void PreloadCache()
    {
        new Thread(() =>
        {
            var sw = Stopwatch.StartNew();
            AllEntries();
            Plugin.Log.Debug($"Warming up auto-translate took {sw.ElapsedMilliseconds}ms");
        }).Start();
    }

    private static List<AutoTranslateEntry> AllEntries()
    {
        if (Entries.TryGetValue(Plugin.DataManager.Language, out var entries))
            return entries;

        var shouldAdd = ValidEntries.Count == 0;

        var parser = Parser();
        var list = new List<AutoTranslateEntry>();
        foreach (var row in CompletionSheet)
        {
            var lookup = row.LookupTable.TextValue();
            if (lookup is not ("" or "@"))
            {
                var (sheetName, selector) = parser.ParseOrThrow(lookup);
                var sheetType = typeof(Completion)
                    .Assembly
                    .GetType($"Lumina.Excel.GeneratedSheets.{sheetName}")!;
                var getSheet = Plugin.DataManager
                    .GetType()
                    .GetMethod("GetExcelSheet", Type.EmptyTypes)!
                    .MakeGenericMethod(sheetType);
                var sheet = (ExcelSheetImpl) getSheet.Invoke(Plugin.DataManager, null)!;
                var rowParsers = sheet.GetRowParsers().ToArray();

                var columns = new List<int>();
                var rows = new List<Range>();
                if (selector.HasValue)
                {
                    columns.Clear();
                    rows.Clear();
                    foreach (var part in selector.Value)
                    {
                        switch (part)
                        {
                            case IndexRange range:
                            {
                                var start = (int) range.Start;
                                var end = (int) (range.End + 1);
                                rows.Add(start..end);
                                break;
                            }
                            case SingleRow single:
                            {
                                var idx = (int) single.Row;
                                rows.Add(idx..(idx + 1));
                                break;
                            }
                            case ColumnSpecifier col:
                                columns.Add((int) col.Column);
                                break;
                        }
                    }
                }

                if (columns.Count == 0)
                    columns.Add(0);

                var validRows = rowParsers.Select(p => p.RowId).ToArray();
                if (rows.Count == 0)
                    // We can't use an "index from end" (like `^0`) here because
                    // we're iterating over integers, not an array directly.
                    // Previously, we were setting `0..^0` which caused these
                    // sheets to be completely skipped due to this bug.
                    // See below.
                    rows.Add(..Index.FromStart((int)validRows.Max() + 1));

                foreach (var range in rows)
                {
                    // We iterate over the range by numerical values here, so
                    // we can't use an "index from end" otherwise nothing will
                    // happen.
                    // See above.
                    for (var i = range.Start.Value; i < range.End.Value; i++)
                    {
                        if (!validRows.Contains((uint) i))
                            continue;

                        foreach (var col in columns)
                        {
                            var rowParser = rowParsers.FirstOrDefault(p => p.RowId == i);
                            if (rowParser == null)
                                continue;

                            var rawName = rowParser.ReadColumn<Lumina.Text.SeString>(col)!;
                            var name = rawName.ToDalamudString();
                            var text = name.TextValue;
                            if (text.Length > 0)
                            {
                                list.Add(new AutoTranslateEntry(
                                    row.Group,
                                    (uint) i,
                                    text,
                                    name
                                ));

                                if (shouldAdd)
                                    ValidEntries.Add((row.Group, (uint) i));
                            }
                        }
                    }
                }
            }
            else if (lookup is not "@")
            {
                var text = row.Text.ToDalamudString();
                list.Add(new AutoTranslateEntry(
                    row.Group,
                    row.RowId,
                    text.TextValue,
                    text
                ));

                if (shouldAdd)
                    ValidEntries.Add((row.Group, row.RowId));
            }
        }

        Entries[Plugin.DataManager.Language] = list;
        return list;
    }

    internal static List<AutoTranslateEntry> Matching(string prefix, bool sort)
    {
        var wholeMatches = new List<AutoTranslateEntry>();
        var prefixMatches = new List<AutoTranslateEntry>();
        var otherMatches = new List<AutoTranslateEntry>();
        foreach (var entry in AllEntries())
        {
            if (entry.String.Equals(prefix, StringComparison.OrdinalIgnoreCase))
                wholeMatches.Add(entry);
            else if (entry.String.StartsWith(prefix, StringComparison.OrdinalIgnoreCase))
                prefixMatches.Add(entry);
            else if (entry.String.Contains(prefix, StringComparison.OrdinalIgnoreCase))
                otherMatches.Add(entry);
        }

        if (sort)
        {
            return wholeMatches.OrderBy(entry => entry.String, StringComparer.OrdinalIgnoreCase)
                .Concat(prefixMatches.OrderBy(entry => entry.String, StringComparer.OrdinalIgnoreCase))
                .Concat(otherMatches.OrderBy(entry => entry.String, StringComparer.OrdinalIgnoreCase))
                .ToList();
        }

        return wholeMatches
            .Concat(prefixMatches)
            .Concat(otherMatches)
            .ToList();
    }

    [DllImport("msvcrt.dll", CallingConvention = CallingConvention.Cdecl)]
    private static extern int memcmp(byte[] b1, byte[] b2, UIntPtr count);

    internal static void ReplaceWithPayload(ref byte[] bytes)
    {
        var search = "<at:"u8.ToArray();
        if (bytes.Length <= search.Length)
            return;

        // populate the list of valid entries
        if (ValidEntries.Count == 0)
            AllEntries();

        var start = -1;
        for (var i = 0; i < bytes.Length; i++)
        {
            if (start != -1) {
                if (bytes[i] == '>')
                {
                    var tag = Encoding.UTF8.GetString(bytes[start..(i + 1)]);
                    var parts = tag[4..^1].Split(',', 2);
                    if (parts.Length == 2 && uint.TryParse(parts[0], out var group) && uint.TryParse(parts[1], out var key))
                    {
                        var payload = ValidEntries.Contains((group, key))
                            ? new AutoTranslatePayload(group, key).Encode()
                            : [];

                        var oldBytes = bytes.ToArray();
                        var lengthDiff = payload.Length - (i - start);
                        bytes = new byte[oldBytes.Length + lengthDiff];
                        Array.Copy(oldBytes, bytes, start);
                        Array.Copy(payload, 0, bytes, start, payload.Length);
                        Array.Copy(oldBytes, i + 1, bytes, start + payload.Length, oldBytes.Length - (i + 1));

                        i += lengthDiff;
                    }

                    start = -1;
                }
                else
                {
                    continue;
                }
            }

            if (i + search.Length < bytes.Length && memcmp(bytes[i..], search, (UIntPtr) search.Length) == 0)
                start = i;
        }
    }
}

internal interface ISelectorPart { }

internal class SingleRow : ISelectorPart
{
    public uint Row { get; }

    public SingleRow(uint row)
    {
        Row = row;
    }
}

internal class IndexRange : ISelectorPart
{
    public uint Start { get; }
    public uint End { get; }

    public IndexRange(uint start, uint end)
    {
        Start = start;
        End = end;
    }
}

internal class NounMarker : ISelectorPart { }

internal class ColumnSpecifier : ISelectorPart
{
    public uint Column { get; }

    public ColumnSpecifier(uint column)
    {
        Column = column;
    }
}

internal class AutoTranslateEntry
{
    internal uint Group { get; }
    internal uint Row { get; }
    internal string String { get; }
    internal SeString SeString { get; }

    public AutoTranslateEntry(uint group, uint row, string str, SeString seStr)
    {
        Group = group;
        Row = row;
        String = str;
        SeString = seStr;
    }
}