using System.Text.Json;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using ProposalSystem.Application.DTOs;
using ProposalSystem.Application.Interfaces;
using ProposalSystem.Domain.Entities;
using ProposalSystem.Infrastructure.Data;

namespace ProposalSystem.Api.Controllers;

[ApiController]
[Route("api/proposals/{proposalId:guid}")]
[Authorize]
public class FilesController : ControllerBase
{
    private readonly ProposalDbContext _db;
    private readonly IS3Service _s3;
    private readonly IJobPublisher _jobPublisher;
    private readonly IAuditService _audit;
    private readonly IConfiguration _config;

    public FilesController(
        ProposalDbContext db,
        IS3Service s3,
        IJobPublisher jobPublisher,
        IAuditService audit,
        IConfiguration config)
    {
        _db = db;
        _s3 = s3;
        _jobPublisher = jobPublisher;
        _audit = audit;
        _config = config;
    }

    [HttpPost("attachments")]
    public async Task<ActionResult<PresignedUploadResponse>> UploadAttachment(
        Guid proposalId,
        [FromQuery] string fileName,
        CancellationToken ct)
    {
        var proposal = await _db.Proposals.FindAsync(new object[] { proposalId }, ct);
        if (proposal == null) return NotFound();

        var extension = Path.GetExtension(fileName).ToLowerInvariant();
        if (extension != ".pdf")
            return BadRequest(new { error = "Only PDF files are accepted" });

        var s3Key = $"vendors/{proposalId}/{Guid.NewGuid()}{extension}";
        var bucket = _config["UPLOADS_BUCKET"]!;

        var url = await _s3.GeneratePresignedUploadUrlAsync(bucket, s3Key, "application/pdf");

        var vendorProposal = new VendorProposal
        {
            Id = Guid.NewGuid(),
            ProposalId = proposalId,
            FileName = fileName,
            S3Key = s3Key,
            UploadedAt = DateTime.UtcNow,
            ProcessingStatus = ProcessingStatus.Pending,
        };

        _db.VendorProposals.Add(vendorProposal);
        await _db.SaveChangesAsync(ct);

        await _jobPublisher.PublishAsync("pdf-extract", new { proposalId, s3Key, vendorProposalId = vendorProposal.Id }, ct);

        return Ok(new PresignedUploadResponse(url, s3Key, DateTime.UtcNow.AddMinutes(15)));
    }

    [HttpGet("pdf")]
    [Authorize(Roles = "admins,sysadmins")]
    public async Task<ActionResult<PdfDownloadResponse>> GetPdf(Guid proposalId, CancellationToken ct)
    {
        var pdf = await _db.GeneratedPdfs
            .Where(p => p.ProposalId == proposalId)
            .OrderByDescending(p => p.Revision)
            .FirstOrDefaultAsync(ct);

        if (pdf == null)
        {
            await _jobPublisher.PublishAsync("pdf-generate", new { proposalId }, ct);
            return Accepted(new { message = "PDF generation queued" });
        }

        var bucket = _config["GENERATED_BUCKET"]!;
        var url = await _s3.GeneratePresignedDownloadUrlAsync(bucket, pdf.S3Key, 60);

        await _audit.LogAsync(AuditAction.Download, proposalId, $"Downloaded rev {pdf.Revision}", ct);

        return Ok(new PdfDownloadResponse(url, DateTime.UtcNow.AddMinutes(60)));
    }

    [HttpGet("pdf/{revision:int}")]
    [Authorize(Roles = "admins,sysadmins")]
    public async Task<ActionResult<PdfDownloadResponse>> GetPdfRevision(
        Guid proposalId,
        int revision,
        CancellationToken ct)
    {
        var pdf = await _db.GeneratedPdfs
            .FirstOrDefaultAsync(p => p.ProposalId == proposalId && p.Revision == revision, ct);

        if (pdf == null) return NotFound();

        var bucket = _config["GENERATED_BUCKET"]!;
        var url = await _s3.GeneratePresignedDownloadUrlAsync(bucket, pdf.S3Key, 60);

        await _audit.LogAsync(AuditAction.Download, proposalId, $"Downloaded rev {revision}", ct);

        return Ok(new PdfDownloadResponse(url, DateTime.UtcNow.AddMinutes(60)));
    }

    [HttpGet("vendors")]
    [Authorize(Roles = "admins,sysadmins")]
    public async Task<ActionResult<IReadOnlyList<VendorProposalResponse>>> GetVendors(
        Guid proposalId,
        CancellationToken ct)
    {
        var entities = await _db.VendorProposals
            .Where(v => v.ProposalId == proposalId)
            .OrderByDescending(v => v.UploadedAt)
            .ToListAsync(ct);

        var vendors = entities.Select(v => new VendorProposalResponse(
            v.Id,
            v.VendorName,
            v.FileName,
            v.TotalVendorCost,
            v.ProcessingStatus.ToString(),
            string.IsNullOrEmpty(v.ExtractedData) ? null : JsonSerializer.Deserialize<object>(v.ExtractedData)
        )).ToList();

        return Ok(vendors);
    }
}