using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Data.Common;
using System.IO;
using System.Linq;
using System.Linq.Expressions;
using System.Text.Json;
using Avalonia.Threading;
using MercuryConverter.UI.Views;
using SaturnData.Notation.Core;
using SaturnData.Notation.Serialization;
using SaturnData.Notation.Serialization.Mer;
using UAssetAPI;
using UAssetAPI.ExportTypes;
using UAssetAPI.PropertyTypes.Objects;
using UAssetAPI.PropertyTypes.Structs;
using UAssetAPI.UnrealTypes;

namespace MercuryConverter.Data;

public static class Database
{
    public static ObservableCollection<Song> Songs = new();

    public static void SetupNew(string dataPath)
    {
        Dispatcher.UIThread.Invoke(() => Songs.Clear());

        var metadataTablePath = Path.Combine(dataPath, "MusicParameterTable.uasset");
        var metadataAsset = new UAsset(metadataTablePath, EngineVersion.VER_UE4_19);
        var metadataTable = metadataAsset.Exports[0] as DataTableExport;

        foreach (var data in metadataTable!.Table.Data)
        {
            if (data["AssetDirectory"].ToString()!.Contains("S99"))
            {
                continue;
            }

            var previewBegin = ((FloatPropertyData)data["PreviewBeginTime"]).Value;
            var previewLen = ((FloatPropertyData)data["PreviewSeconds"]).Value;

            string? cTxt = data["CopyrightMessage"].ToString();

            var jacketPath = $"{Path.Combine(dataPath, "jackets", data["JacketAssetName"].ToString()!)}.png";

            try
            {
                var song = new Song
                {
                    Id = data["AssetDirectory"].ToString()!,
                    Rubi = data["Rubi"].ToString()!,
                    Name = data["MusicMessage"].ToString()!,
                    Artist = data["ArtistMessage"].ToString()!,
                    Genre = ((IntPropertyData)data["ScoreGenre"]).Value,
                    Source = ((UInt32PropertyData)data["VersionNo"]).Value,
                    BpmMessage = data["Bpm"].ToString()!,
                    PreviewTime = previewBegin,
                    PreviewLen = previewLen,
                    Jacket = File.Exists(jacketPath) ? jacketPath : null,
                    Copyright = (cTxt == "-" || cTxt == "") ? null : cTxt,
                    assetData = data,
                };

                foreach (Difficulty diff in Enum.GetValues(typeof(Difficulty)))
                {
                    // skip non-canon difficulties
                    if (diff == Difficulty.None || diff == Difficulty.WorldsEnd) continue;

                    var lvl = ((FloatPropertyData)data[Consts.DIFF_LVL_KEY[diff]]).Value;
                    if (lvl == 0) continue; // skip nonexistent level

                    // check chart existence
                    var chartFilePath = Path.Combine(dataPath, "MusicData", song.Id, $"{song.Id}_{Consts.DIFF_FILENAME_APPEND[diff]}.mer");
                    if (!File.Exists(chartFilePath))
                    {
                        // TODO: add warning message to DataScan
                        Console.WriteLine($"[MISSING CHART] {song.Id} {song.Artist} - {song.Name} / {diff}");
                        continue;
                    }

                    // TODO: check audio existence; add warning but don't skip if missing
                    song.Levels[(int)diff] = (lvl, data[Consts.DIFF_DESIGNER_KEY[diff]].ToString()!);
                }

                Dispatcher.UIThread.Post(() => Songs.Add(song));
            }
            catch (Exception e)
            {
                Console.WriteLine($"Couldn't construct a song!\n{e}");
            }
        }
        Console.WriteLine("Data setup finished.");
    }
}