using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;
using D3ROVoice.Api.Dtos;
using D3ROVoice.Api.Services;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;

namespace D3ROVoice.Api.Controllers;

[ApiController]
[Authorize]
[Route("api/[controller]")]
public class SttController : ControllerBase
{
    private const string InternalGatewayHeader = "X-D3RO-STT-Gateway-Token";
    private readonly ISttProxyService _sttService;
    private readonly IConfiguration _configuration;

    public SttController(ISttProxyService sttService, IConfiguration configuration)
    {
        _sttService = sttService;
        _configuration = configuration;
    }

    [HttpPost("transcribe")]
    [Consumes("application/json", "multipart/form-data")]
    public Task<IActionResult> Transcribe()
    {
        // User-facing transcription is exclusively handled by the Supabase
        // stt-proxy, which owns authenticated identity, quota reservation and
        // usage persistence. This legacy provider path must not bypass it.
        return Task.FromResult<IActionResult>(StatusCode(
            StatusCodes.Status410Gone,
            new { error = "stt_edge_gateway_required" }));
    }

    [HttpPost("internal/transcribe")]
    [AllowAnonymous]
    [Consumes("multipart/form-data")]
    [RequestSizeLimit(26 * 1024 * 1024)]
    public async Task<IActionResult> TranscribeFromQuotaGateway()
    {
        var configuredToken = _configuration["D3RO_API_TOKEN"]?.Trim() ?? string.Empty;
        if (Encoding.UTF8.GetByteCount(configuredToken) < 32)
        {
            return StatusCode(StatusCodes.Status503ServiceUnavailable, new { error = "stt_gateway_not_configured" });
        }

        var suppliedToken = Request.Headers[InternalGatewayHeader].ToString();
        if (!FixedTimeTokenEquals(configuredToken, suppliedToken))
        {
            return Unauthorized(new { error = "stt_gateway_unauthorized" });
        }

        if (!Request.HasFormContentType)
        {
            return StatusCode(StatusCodes.Status415UnsupportedMediaType, new { error = "unsupported_media_type" });
        }

        var form = await Request.ReadFormAsync();
        var file = form.Files.GetFile("file") ?? form.Files.GetFile("audio");
        if (file == null || file.Length == 0)
        {
            return BadRequest(new { error = "missing_audio" });
        }

        await using var memoryStream = new MemoryStream();
        await file.CopyToAsync(memoryStream);
        var language = form["language"].ToString();
        var prompt = form["prompt"].ToString();
        var request = new SttTranscribeRequest(
            AudioBase64: null,
            Language: string.IsNullOrWhiteSpace(language) ? "ko" : language,
            InitialPrompt: string.IsNullOrWhiteSpace(prompt) ? null : prompt,
            ModelId: null,
            Provider: null);

        try
        {
            var result = await _sttService.TranscribeAsync(
                userId: 0,
                userEmail: "edge-internal",
                request,
                memoryStream.ToArray(),
                file.ContentType ?? "application/octet-stream",
                file.FileName ?? "recording.bin",
                recordUsage: false);
            return Ok(result);
        }
        catch (SttProviderUnavailableException)
        {
            return StatusCode(StatusCodes.Status503ServiceUnavailable, new { error = "stt_provider_unavailable" });
        }
        catch (ArgumentException)
        {
            return BadRequest(new { error = "invalid_audio" });
        }
        catch
        {
            return StatusCode(StatusCodes.Status502BadGateway, new { error = "stt_upstream_failed" });
        }
    }

    private static bool FixedTimeTokenEquals(string configured, string supplied)
    {
        var configuredDigest = SHA256.HashData(Encoding.UTF8.GetBytes(configured));
        var suppliedDigest = SHA256.HashData(Encoding.UTF8.GetBytes(supplied));
        return CryptographicOperations.FixedTimeEquals(configuredDigest, suppliedDigest);
    }

    [HttpGet("providers")]
    [Authorize(Policy = "ManagerOrAbove")]
    public async Task<IActionResult> GetActiveProviders()
    {
        var endpoints = await _sttService.GetAllEndpointsAsync();
        return Ok(endpoints);
    }

    [HttpPost("test")]
    [Authorize(Policy = "ManagerOrAbove")]
    public async Task<IActionResult> TestConnection([FromQuery] int endpointId = 0)
    {
        var result = await _sttService.TestEndpointAsync(endpointId);
        return Ok(result);
    }
}