using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using ProposalSystem.Application.DTOs;
using ProposalSystem.Domain.Entities;
using ProposalSystem.Infrastructure.Data;

namespace ProposalSystem.Api.Controllers;

[ApiController]
[Route("api/admin")]
[Authorize(Roles = "admins,sysadmins")]
public class AdminController : ControllerBase
{
    private readonly ProposalDbContext _db;

    public AdminController(ProposalDbContext db)
    {
        _db = db;
    }

    [HttpGet("dashboard")]
    public async Task<ActionResult<DashboardResponse>> GetDashboard(CancellationToken ct)
    {
        // Fix: API-M7 — AsNoTracking on read-only dashboard queries
        var pendingCount = await _db.Proposals
            .AsNoTracking()
            .CountAsync(p => p.Status == ProposalStatus.InReview, ct);

        var weekStart = DateTime.UtcNow.AddDays(-7);
        var approvedThisWeek = await _db.Proposals
            .AsNoTracking()
            .CountAsync(p => p.ApprovedAt >= weekStart, ct);

        var approvedCount = await _db.Proposals
            .AsNoTracking()
            .CountAsync(p => p.ApprovedAt.HasValue, ct);

        double avgTurnaround = 0;
        if (approvedCount > 0)
        {
            var recentApproved = await _db.Proposals
                .AsNoTracking()
                .Where(p => p.ApprovedAt.HasValue)
                .OrderByDescending(p => p.ApprovedAt)
                .Take(200)
                .Select(p => new { p.ApprovedAt, p.SubmittedAt })
                .ToListAsync(ct);
            avgTurnaround = recentApproved.Average(p => (p.ApprovedAt!.Value - p.SubmittedAt).TotalHours);
        }

        var totalProposals = await _db.Proposals.AsNoTracking().CountAsync(ct);

        return Ok(new DashboardResponse(pendingCount, approvedThisWeek, avgTurnaround, totalProposals));
    }
}