using System.Collections.Immutable;
using System.Reflection;
using System.Text.Json;
using Microsoft.Extensions.Logging;
using RPG.GameCore.Excel.Attributes;

namespace RPG.GameCore.Excel;
public class ExcelTables
{
    private readonly ILogger _logger;
    private ImmutableDictionary<ExcelType, ImmutableArray<ExcelRow>>? _tables;

    public ExcelTables(ILogger<ExcelTables> logger)
    {
        _logger = logger;
    }

    public TExcelRow? GetExcelRow<TExcelRow>(ExcelType type, uint id) where TExcelRow : ExcelRow
    {
        if (_tables == null) throw new InvalidOperationException("GetExcelRow called when ExcelTables not loaded.");

        if (_tables.TryGetValue(type, out ImmutableArray<ExcelRow> rows))
        {
            return rows.SingleOrDefault(row => row.Id == id) as TExcelRow;
        }

        throw new ArgumentException($"GetExcelRow: table for excel type not found {type}");
    }

    public IEnumerable<ExcelRow> GetAllRows(ExcelType type)
    {
        if (_tables == null) throw new InvalidOperationException("GetAllRows called when ExcelTables not loaded.");

        if (_tables.TryGetValue(type, out ImmutableArray<ExcelRow> rows))
        {
            return rows;
        }

        throw new ArgumentException($"GetAllRows: table for excel type not found {type}");
    }

    public void Load()
    {
        ImmutableDictionary<ExcelType, ImmutableArray<ExcelRow>>.Builder tables = ImmutableDictionary.CreateBuilder<ExcelType, ImmutableArray<ExcelRow>>();

        IEnumerable<Type> types = Assembly.GetExecutingAssembly().GetTypes()
                                  .Where(type => type.GetCustomAttribute<ExcelTableAttribute>() != null);

        foreach (Type type in types)
        {
            ExcelTableAttribute attribute = type.GetCustomAttribute<ExcelTableAttribute>()!;

            // TODO: asset provider

            JsonDocument tableJson = JsonDocument.Parse(File.ReadAllText("data/ExcelBinOutput/" + attribute.Path));
            ImmutableArray<ExcelRow>.Builder rows = ImmutableArray.CreateBuilder<ExcelRow>();

            foreach (JsonProperty property in tableJson.RootElement.EnumerateObject())
            {
                if (property.Value.ValueKind != JsonValueKind.Object)
                    throw new ArgumentException($"Failed to load excel: expected an object, got {property.Value.ValueKind}");

                ExcelRow row = (property.Value.Deserialize(type) as ExcelRow)!;
                rows.Add(row);
            }

            tables.Add(attribute.Type, rows.ToImmutable());
        }

        _tables = tables.ToImmutable();
        _logger.LogInformation("Loaded {count} excel tables", _tables.Count);
    }
}