using Microsoft.AspNetCore.Mvc;
using DramaLing.Api.Models.Entities;
using DramaLing.Api.Models.DTOs;
using DramaLing.Api.Contracts.Repositories;
using DramaLing.Api.Contracts.Services.Review;
using Microsoft.AspNetCore.Authorization;
using DramaLing.Api.Utils;
using DramaLing.Api.Services;
using DramaLing.Api.Services.Storage;
using DramaLing.Api.Data;
using Microsoft.EntityFrameworkCore;

namespace DramaLing.Api.Controllers;

[Route("api/flashcards")]
[Authorize]
public class FlashcardsController : BaseController
{
    private readonly IFlashcardRepository _flashcardRepository;
    private readonly IReviewService _reviewService;
    private readonly DramaLingDbContext _context;
    private readonly IImageStorageService _imageStorageService;

    public FlashcardsController(
        IFlashcardRepository flashcardRepository,
        IReviewService reviewService,
        DramaLingDbContext context,
        IImageStorageService imageStorageService,
        IAuthService authService,
        ILogger<FlashcardsController> logger) : base(logger, authService)
    {
        _flashcardRepository = flashcardRepository;
        _reviewService = reviewService;
        _context = context;
        _imageStorageService = imageStorageService;
    }

    private async Task<string?> GetImageUrlAsync(string? relativePath)
    {
        if (string.IsNullOrEmpty(relativePath))
            return null;

        // 確保路徑包含 examples/ 前綴
        var fullPath = relativePath.StartsWith("examples/")
            ? relativePath
            : $"examples/{relativePath}";

        return await _imageStorageService.GetImageUrlAsync(fullPath);
    }

    [HttpGet]
    public async Task<IActionResult> GetFlashcards(
        [FromQuery] string? search = null,
        [FromQuery] bool favoritesOnly = false)
    {
        try
        {
            var userId = await GetCurrentUserIdAsync();
            var flashcards = await _flashcardRepository.GetByUserIdAsync(userId, search, favoritesOnly);

            // 獲取用戶的複習記錄
            var flashcardIds = flashcards.Select(f => f.Id).ToList();
            var reviews = await _context.FlashcardReviews
                .Where(fr => fr.UserId == userId && flashcardIds.Contains(fr.FlashcardId))
                .ToDictionaryAsync(fr => fr.FlashcardId);

            // 重構為 foreach 迴圈，支援異步 URL 處理
            var flashcardList = new List<object>();

            foreach (var f in flashcards)
            {
                reviews.TryGetValue(f.Id, out var review);

                // 取得主要圖片的相對路徑並轉換為完整 URL
                var primaryImageRelativePath = f.FlashcardExampleImages
                    .Where(fei => fei.IsPrimary)
                    .Select(fei => fei.ExampleImage.RelativePath)
                    .FirstOrDefault();

                var primaryImageUrl = await GetImageUrlAsync(primaryImageRelativePath);

                flashcardList.Add(new
                {
                    f.Id,
                    f.Word,
                    f.Translation,
                    f.Definition,
                    f.PartOfSpeech,
                    f.Pronunciation,
                    f.Example,
                    f.ExampleTranslation,
                    f.IsFavorite,
                    f.Synonyms,
                    DifficultyLevelNumeric = f.DifficultyLevelNumeric,
                    CEFR = CEFRHelper.ToString(f.DifficultyLevelNumeric),
                    f.CreatedAt,
                    f.UpdatedAt,
                    // 添加複習相關屬性
                    NextReviewDate = review?.NextReviewDate ?? DateTime.UtcNow.AddDays(1),
                    TimesReviewed = review?.TotalCorrectCount + review?.TotalWrongCount + review?.TotalSkipCount ?? 0,
                    MasteryLevel = review?.SuccessCount ?? 0,
                    // 添加圖片相關屬性
                    HasExampleImage = f.FlashcardExampleImages.Any(),
                    PrimaryImageUrl = primaryImageUrl
                });
            }

            var flashcardData = new
            {
                Flashcards = flashcardList,
                Count = flashcards.Count()
            };

            return SuccessResponse(flashcardData);
        }
        catch (UnauthorizedAccessException)
        {
            return ErrorResponse("UNAUTHORIZED", "認證失敗", null, 401);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error getting flashcards");
            return ErrorResponse("INTERNAL_ERROR", "載入詞卡失敗");
        }
    }

    [HttpPost]
    public async Task<IActionResult> CreateFlashcard([FromBody] CreateFlashcardRequest request)
    {
        try
        {
            if (!ModelState.IsValid)
            {
                return HandleModelStateErrors();
            }

            var userId = await GetCurrentUserIdAsync();

            var flashcard = new Flashcard
            {
                Id = Guid.NewGuid(),
                UserId = userId,
                Word = request.Word,
                Translation = request.Translation,
                Definition = request.Definition ?? "",
                PartOfSpeech = request.PartOfSpeech,
                Pronunciation = request.Pronunciation,
                Example = request.Example,
                ExampleTranslation = request.ExampleTranslation,
                Synonyms = request.Synonyms, // 儲存 AI 生成的同義詞
                DifficultyLevelNumeric = CEFRHelper.ToNumeric(request.CEFR ?? "A0"),
                CreatedAt = DateTime.UtcNow,
                UpdatedAt = DateTime.UtcNow
            };

            await _flashcardRepository.AddAsync(flashcard);
            await _flashcardRepository.SaveChangesAsync();

            return SuccessResponse(flashcard, "詞卡創建成功");
        }
        catch (UnauthorizedAccessException)
        {
            return ErrorResponse("UNAUTHORIZED", "認證失敗", null, 401);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error creating flashcard");
            return ErrorResponse("INTERNAL_ERROR", "創建詞卡失敗");
        }
    }

    [HttpGet("{id}")]
    public async Task<IActionResult> GetFlashcard(Guid id)
    {
        try
        {
            var userId = await GetCurrentUserIdAsync();

            var flashcard = await _flashcardRepository.GetByUserIdAndFlashcardIdAsync(userId, id);

            if (flashcard == null)
            {
                return ErrorResponse("NOT_FOUND", "詞卡不存在", null, 404);
            }

            // 獲取複習記錄
            var review = await _context.FlashcardReviews
                .FirstOrDefaultAsync(fr => fr.UserId == userId && fr.FlashcardId == id);

            // 格式化返回數據，保持與列表 API 一致
            var flashcardData = new
            {
                flashcard.Id,
                flashcard.Word,
                flashcard.Translation,
                flashcard.Definition,
                flashcard.PartOfSpeech,
                flashcard.Pronunciation,
                flashcard.Example,
                flashcard.ExampleTranslation,
                flashcard.IsFavorite,
                flashcard.Synonyms,
                DifficultyLevelNumeric = flashcard.DifficultyLevelNumeric,
                CEFR = CEFRHelper.ToString(flashcard.DifficultyLevelNumeric),
                flashcard.CreatedAt,
                flashcard.UpdatedAt,
                // 添加複習相關屬性（與列表 API 一致）
                NextReviewDate = review?.NextReviewDate ?? DateTime.UtcNow.AddDays(1),
                TimesReviewed = review?.TotalCorrectCount + review?.TotalWrongCount + review?.TotalSkipCount ?? 0,
                MasteryLevel = review?.SuccessCount ?? 0,
                // 添加圖片相關屬性
                HasExampleImage = flashcard.FlashcardExampleImages.Any(),
                PrimaryImageUrl = await GetImageUrlAsync(flashcard.FlashcardExampleImages
                    .Where(fei => fei.IsPrimary)
                    .Select(fei => fei.ExampleImage.RelativePath)
                    .FirstOrDefault()),
                // 保留完整的圖片關聯數據供前端使用
                FlashcardExampleImages = flashcard.FlashcardExampleImages
            };

            return SuccessResponse(flashcardData);
        }
        catch (UnauthorizedAccessException)
        {
            return ErrorResponse("UNAUTHORIZED", "認證失敗", null, 401);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error getting flashcard {FlashcardId}", id);
            return ErrorResponse("INTERNAL_ERROR", "取得詞卡失敗");
        }
    }

    [HttpPut("{id}")]
    public async Task<IActionResult> UpdateFlashcard(Guid id, [FromBody] CreateFlashcardRequest request)
    {
        try
        {
            if (!ModelState.IsValid)
            {
                return HandleModelStateErrors();
            }

            var userId = await GetCurrentUserIdAsync();

            var flashcard = await _flashcardRepository.GetByUserIdAndFlashcardIdAsync(userId, id);

            if (flashcard == null)
            {
                return ErrorResponse("NOT_FOUND", "詞卡不存在", null, 404);
            }

            // 更新詞卡資訊
            flashcard.Word = request.Word;
            flashcard.Translation = request.Translation;
            flashcard.Definition = request.Definition ?? "";
            flashcard.PartOfSpeech = request.PartOfSpeech;
            flashcard.Pronunciation = request.Pronunciation;
            flashcard.Example = request.Example;
            flashcard.ExampleTranslation = request.ExampleTranslation;
            flashcard.UpdatedAt = DateTime.UtcNow;

            await _flashcardRepository.UpdateAsync(flashcard);
            await _flashcardRepository.SaveChangesAsync();

            return SuccessResponse(flashcard, "詞卡更新成功");
        }
        catch (UnauthorizedAccessException)
        {
            return ErrorResponse("UNAUTHORIZED", "認證失敗", null, 401);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error updating flashcard {FlashcardId}", id);
            return ErrorResponse("INTERNAL_ERROR", "更新詞卡失敗");
        }
    }

    [HttpDelete("{id}")]
    public async Task<IActionResult> DeleteFlashcard(Guid id)
    {
        try
        {
            var userId = await GetCurrentUserIdAsync();

            var flashcard = await _flashcardRepository.GetByUserIdAndFlashcardIdAsync(userId, id);

            if (flashcard == null)
            {
                return ErrorResponse("NOT_FOUND", "詞卡不存在", null, 404);
            }

            await _flashcardRepository.DeleteAsync(flashcard);
            await _flashcardRepository.SaveChangesAsync();

            return SuccessResponse(new { Id = id }, "詞卡已刪除");
        }
        catch (UnauthorizedAccessException)
        {
            return ErrorResponse("UNAUTHORIZED", "認證失敗", null, 401);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error deleting flashcard {FlashcardId}", id);
            return ErrorResponse("INTERNAL_ERROR", "刪除詞卡失敗");
        }
    }

    [HttpPost("{id}/favorite")]
    public async Task<IActionResult> ToggleFavorite(Guid id)
    {
        try
        {
            var userId = await GetCurrentUserIdAsync();

            var flashcard = await _flashcardRepository.GetByUserIdAndFlashcardIdAsync(userId, id);

            if (flashcard == null)
            {
                return ErrorResponse("NOT_FOUND", "詞卡不存在", null, 404);
            }

            flashcard.IsFavorite = !flashcard.IsFavorite;
            flashcard.UpdatedAt = DateTime.UtcNow;

            await _flashcardRepository.UpdateAsync(flashcard);
            await _flashcardRepository.SaveChangesAsync();

            var result = new {
                Id = flashcard.Id,
                IsFavorite = flashcard.IsFavorite
            };

            var message = flashcard.IsFavorite ? "已加入收藏" : "已取消收藏";
            return SuccessResponse(result, message);
        }
        catch (UnauthorizedAccessException)
        {
            return ErrorResponse("UNAUTHORIZED", "認證失敗", null, 401);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error toggling favorite for flashcard {FlashcardId}", id);
            return ErrorResponse("INTERNAL_ERROR", "切換收藏狀態失敗");
        }
    }

    [HttpGet("due")]
    public async Task<IActionResult> GetDueFlashcards(
        [FromQuery] int limit = 10,
        [FromQuery] bool includeToday = true,
        [FromQuery] bool includeOverdue = true,
        [FromQuery] bool favoritesOnly = false)
    {
        try
        {
            var userId = await GetCurrentUserIdAsync();

            var query = new DueFlashcardsQuery
            {
                Limit = limit,
                IncludeToday = includeToday,
                IncludeOverdue = includeOverdue,
                FavoritesOnly = favoritesOnly
            };

            var response = await _reviewService.GetDueFlashcardsAsync(userId, query);
            return Ok(response);
        }
        catch (UnauthorizedAccessException)
        {
            return ErrorResponse("UNAUTHORIZED", "認證失敗", null, 401);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error getting due flashcards");
            return ErrorResponse("INTERNAL_ERROR", "載入待複習詞卡失敗");
        }
    }

    [HttpPost("{id}/review")]
    public async Task<IActionResult> SubmitReview(Guid id, [FromBody] ReviewRequest request)
    {
        try
        {
            if (!ModelState.IsValid)
            {
                return HandleModelStateErrors();
            }

            var userId = await GetCurrentUserIdAsync();
            var response = await _reviewService.SubmitReviewAsync(userId, id, request);
            return Ok(response);
        }
        catch (UnauthorizedAccessException)
        {
            return ErrorResponse("UNAUTHORIZED", "認證失敗", null, 401);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error submitting review for flashcard {FlashcardId}", id);
            return ErrorResponse("INTERNAL_ERROR", "提交複習結果失敗");
        }
    }

    [HttpPost("{id}/mastered")]
    public async Task<IActionResult> MarkWordMastered(Guid id)
    {
        try
        {
            var userId = await GetCurrentUserIdAsync();
            var response = await _reviewService.MarkWordMasteredAsync(userId, id);
            return Ok(response);
        }
        catch (UnauthorizedAccessException)
        {
            return ErrorResponse("UNAUTHORIZED", "認證失敗", null, 401);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error marking flashcard {FlashcardId} as mastered", id);
            return ErrorResponse("INTERNAL_ERROR", "標記詞彙掌握失敗");
        }
    }
}

// DTO 類別
public class CreateFlashcardRequest
{
    public string Word { get; set; } = string.Empty;
    public string Translation { get; set; } = string.Empty;
    public string Definition { get; set; } = string.Empty;
    public string PartOfSpeech { get; set; } = string.Empty;
    public string Pronunciation { get; set; } = string.Empty;
    public string Example { get; set; } = string.Empty;
    public string? ExampleTranslation { get; set; }
    public string? Synonyms { get; set; } // AI 生成的同義詞 (JSON 字串)
    public string? CEFR { get; set; } = string.Empty;
}