package logic

import (
	"context"
	"database/sql"
	"fmt"

	"git.cialloo.com/CiallooWeb/Blog/app/internal/svc"
	"git.cialloo.com/CiallooWeb/Blog/app/internal/types"
	"git.cialloo.com/CiallooWeb/Blog/app/internal/utils"

	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/zeromicro/go-zero/core/logx"
)

type CreatePostLogic struct {
	logx.Logger
	ctx    context.Context
	svcCtx *svc.ServiceContext
}

// Create a new blog post
func NewCreatePostLogic(ctx context.Context, svcCtx *svc.ServiceContext) *CreatePostLogic {
	return &CreatePostLogic{
		Logger: logx.WithContext(ctx),
		ctx:    ctx,
		svcCtx: svcCtx,
	}
}

func (l *CreatePostLogic) CreatePost(req *types.CreatePostReq) (resp *types.CreatePostResp, err error) {
	// Start a transaction
	tx, err := l.svcCtx.DB.BeginTx(l.ctx, nil)
	if err != nil {
		l.Errorf("Failed to begin transaction: %v", err)
		return nil, err
	}
	defer tx.Rollback()

	// Extract all image file keys from content
	imageKeys, err := utils.ExtractImageKeysFromContent(req.Content)
	if err != nil {
		l.Errorf("Failed to parse content: %v", err)
		return nil, fmt.Errorf("invalid content format")
	}

	// Migrate cover image from tmpfiles to files if provided
	var coverID sql.NullInt64
	if req.CoverImageKey != "" {
		fileID, err := l.migrateFileFromTmpToFiles(tx, req.CoverImageKey)
		if err != nil {
			return nil, err
		}
		coverID.Int64 = fileID
		coverID.Valid = true
	}

	// Migrate all content images from tmpfiles to files
	for _, imageKey := range imageKeys {
		_, err := l.migrateFileFromTmpToFiles(tx, imageKey)
		if err != nil {
			l.Errorf("Failed to migrate content image %s: %v", imageKey, err)
			// Continue with other images, don't fail the whole operation
		}
	}

	// Insert new post
	var postID int64
	postQuery := `INSERT INTO posts (title, content, cover_id) VALUES ($1, $2, $3) RETURNING id`
	err = tx.QueryRowContext(l.ctx, postQuery, req.Title, req.Content, coverID).Scan(&postID)
	if err != nil {
		l.Errorf("Failed to create post: %v", err)
		return nil, err
	}

	// Commit transaction
	if err = tx.Commit(); err != nil {
		l.Errorf("Failed to commit transaction: %v", err)
		return nil, err
	}

	return &types.CreatePostResp{
		PostId: fmt.Sprintf("%d", postID),
	}, nil
}

// migrateFileFromTmpToFiles moves a file from tmpfiles to files table
func (l *CreatePostLogic) migrateFileFromTmpToFiles(tx *sql.Tx, fileKey string) (int64, error) {
	// Check if file already exists in files table
	var existingID int64
	checkQuery := `SELECT id FROM files WHERE file_key = $1`
	err := tx.QueryRowContext(l.ctx, checkQuery, fileKey).Scan(&existingID)
	if err == nil {
		// File already exists, return its ID
		return existingID, nil
	}
	if err != sql.ErrNoRows {
		l.Errorf("Failed to check existing file: %v", err)
		return 0, err
	}

	// Verify file exists in S3 bucket
	_, err = l.svcCtx.S3Client.HeadObject(l.ctx, &s3.HeadObjectInput{
		Bucket: &l.svcCtx.Config.S3.Bucket,
		Key:    &fileKey,
	})
	if err != nil {
		l.Errorf("File not found in S3 bucket: %s, error: %v", fileKey, err)
		return 0, fmt.Errorf("file not found in storage")
	}

	// Get file name from tmpfiles (if exists)
	var fileName string
	tmpQuery := `SELECT file_name FROM tmpfiles WHERE key = $1`
	err = tx.QueryRowContext(l.ctx, tmpQuery, fileKey).Scan(&fileName)
	if err != nil && err != sql.ErrNoRows {
		l.Errorf("Failed to get tmpfile: %v", err)
		return 0, err
	}
	if err == sql.ErrNoRows {
		// File not in tmpfiles, use file key as name
		fileName = fileKey
	}

	// Insert into files table
	var fileID int64
	fileQuery := `INSERT INTO files (file_name, file_key) VALUES ($1, $2) RETURNING id`
	err = tx.QueryRowContext(l.ctx, fileQuery, fileName, fileKey).Scan(&fileID)
	if err != nil {
		l.Errorf("Failed to insert file record: %v", err)
		return 0, err
	}

	// Delete from tmpfiles if exists
	deleteQuery := `DELETE FROM tmpfiles WHERE key = $1`
	_, err = tx.ExecContext(l.ctx, deleteQuery, fileKey)
	if err != nil {
		l.Errorf("Failed to delete tmpfile: %v", err)
		// Don't fail the operation for this
	}

	return fileID, nil
}