using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using MoneyMap.Data;
using MoneyMap.Services;

namespace MoneyMap.Controllers;

[ApiController]
[Route("api/[controller]")]
public class DashboardController : ControllerBase
{
    private readonly IDashboardService _dashboardService;
    private readonly MoneyMapContext _db;

    public DashboardController(IDashboardService dashboardService, MoneyMapContext db)
    {
        _dashboardService = dashboardService;
        _db = db;
    }

    [HttpGet]
    public async Task<IActionResult> Get(
        [FromQuery] int? topCategoriesCount = null,
        [FromQuery] int? recentTransactionsCount = null)
    {
        var data = await _dashboardService.GetDashboardDataAsync(
            topCategoriesCount ?? 8,
            recentTransactionsCount ?? 20);

        return Ok(data);
    }

    [HttpGet("monthly-trend")]
    public async Task<IActionResult> MonthlyTrend(
        [FromQuery] int? months = null,
        [FromQuery] string? category = null)
    {
        var monthCount = months ?? 6;
        var endDate = DateTime.Today;
        var startDate = new DateTime(endDate.Year, endDate.Month, 1).AddMonths(-(monthCount - 1));

        var q = _db.Transactions
            .Where(t => t.Date >= startDate && t.Date <= endDate)
            .Where(t => t.Amount < 0)
            .Where(t => t.TransferToAccountId == null)
            .ExcludeTransfers();

        if (!string.IsNullOrWhiteSpace(category))
            q = q.Where(t => t.Category == category);

        var monthly = await q
            .GroupBy(t => new { t.Date.Year, t.Date.Month })
            .Select(g => new
            {
                Year = g.Key.Year,
                Month = g.Key.Month,
                Total = g.Sum(t => Math.Abs(t.Amount)),
                Count = g.Count()
            })
            .OrderBy(x => x.Year).ThenBy(x => x.Month)
            .ToListAsync();

        var result = monthly.Select(m => new
        {
            Period = $"{m.Year}-{m.Month:D2}",
            m.Total,
            m.Count
        }).ToList();

        return Ok(new { Category = category ?? "All Spending", Months = result });
    }
}