using MySqlConnector;
using UtopiaCanteenSystem.Models;

namespace UtopiaCanteenSystem.Services;

/// <summary>
/// Fetches lunch menu from HRMS: lunch_menu_week (by location_site_id) → lunch_menu_item → menu_item.
/// Uses IConfigService.GetHrmsLookupConnectionString(). Only current week is considered.
/// </summary>
public class MenuLookupService : IMenuLookupService
{
    private readonly IConfigService _configService;

    public MenuLookupService(IConfigService configService)
    {
        _configService = configService;
    }

    /// <inheritdoc />
    public async Task<IReadOnlyList<HrmsMenuItem>> GetMenuItemsForSiteAsync(int siteIdNumeric, CancellationToken cancellationToken = default)
    {
        var connectionString = _configService.GetHrmsLookupConnectionString();
        if (string.IsNullOrWhiteSpace(connectionString))
            return Array.Empty<HrmsMenuItem>();

        const string sql = @"
            SELECT DISTINCT mi.id, mi.item_name, mi.item_type, mi.price
            FROM lunch_menu_week w
            JOIN lunch_menu_item li ON li.lunch_menu_week_id = w.id
            JOIN menu_item mi ON mi.id = li.menu_item_id
            WHERE w.location_site_id = @siteId
              AND CURDATE() BETWEEN w.week_start_date AND w.week_end_date
            ORDER BY mi.item_type, mi.item_name";

        await using var conn = new MySqlConnection(connectionString);
        await conn.OpenAsync(cancellationToken).ConfigureAwait(false);
        await using var cmd = new MySqlCommand(sql, conn);
        cmd.Parameters.AddWithValue("@siteId", siteIdNumeric);

        var list = new List<HrmsMenuItem>();
        await using var reader = await cmd.ExecuteReaderAsync(cancellationToken).ConfigureAwait(false);
        while (await reader.ReadAsync(cancellationToken).ConfigureAwait(false))
        {
            list.Add(new HrmsMenuItem
            {
                MenuItemId = reader.IsDBNull(0) ? 0 : reader.GetInt32(0),
                ItemName = GetString(reader, 1),
                ItemType = GetString(reader, 2),
                Price = GetDecimal(reader, 3)
            });
        }

        return list;
    }

    private static string GetString(MySqlDataReader reader, int ordinal)
    {
        if (reader.IsDBNull(ordinal)) return string.Empty;
        var v = reader.GetValue(ordinal);
        return v?.ToString() ?? string.Empty;
    }

    private static decimal GetDecimal(MySqlDataReader reader, int ordinal)
    {
        if (reader.IsDBNull(ordinal)) return 0m;
        var v = reader.GetValue(ordinal);
        return v is decimal d ? d : Convert.ToDecimal(v);
    }
}