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/zeromicro/go-zero/core/logx"
)

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

// Edit an existing blog post
func NewEditPostLogic(ctx context.Context, svcCtx *svc.ServiceContext) *EditPostLogic {
	return &EditPostLogic{
		Logger: logx.WithContext(ctx),
		ctx:    ctx,
		svcCtx: svcCtx,
	}
}

func (l *EditPostLogic) EditPost(req *types.EditPostReq) (resp *types.EditPostResp, 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()

	// Check if post exists and get old cover_id
	var oldCoverID sql.NullInt64
	checkQuery := `SELECT cover_id FROM posts WHERE id = $1`
	err = tx.QueryRowContext(l.ctx, checkQuery, req.PostId).Scan(&oldCoverID)
	if err != nil {
		if err == sql.ErrNoRows {
			l.Errorf("Post not found with id: %s", req.PostId)
			return nil, fmt.Errorf("post not found")
		}
		l.Errorf("Failed to get post: %v", err)
		return nil, err
	}

	// 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 new 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

		// Update post with new cover
		updateQuery := `UPDATE posts SET title = $1, content = $2, cover_id = $3, updated_at = CURRENT_TIMESTAMP WHERE id = $4`
		_, err = tx.ExecContext(l.ctx, updateQuery, req.Title, req.Content, coverID, req.PostId)
		if err != nil {
			l.Errorf("Failed to update post: %v", err)
			return nil, err
		}

		// Delete old cover file if exists and different from new one
		if oldCoverID.Valid && oldCoverID.Int64 != coverID.Int64 {
			deleteOldFileQuery := `DELETE FROM files WHERE id = $1`
			_, err = tx.ExecContext(l.ctx, deleteOldFileQuery, oldCoverID.Int64)
			if err != nil {
				l.Errorf("Failed to delete old cover file: %v", err)
				// Don't fail the whole operation for this
			}
		}
	} else {
		// No new cover image - just update the post
		updateQuery := `UPDATE posts SET title = $1, content = $2, updated_at = CURRENT_TIMESTAMP WHERE id = $3`
		_, err = tx.ExecContext(l.ctx, updateQuery, req.Title, req.Content, req.PostId)
		if err != nil {
			l.Errorf("Failed to update post: %v", err)
			return nil, err
		}
	}

	// 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
		}
	}

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

	return &types.EditPostResp{}, nil
}

// migrateFileFromTmpToFiles moves a file from tmpfiles to files table
func (l *EditPostLogic) 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 tmpfiles table
	var fileName string
	tmpQuery := `SELECT file_name FROM tmpfiles WHERE key = $1`
	err = tx.QueryRowContext(l.ctx, tmpQuery, fileKey).Scan(&fileName)
	if err != nil {
		if err == sql.ErrNoRows {
			l.Errorf("File not found in tmpfiles with key: %s", fileKey)
			return 0, fmt.Errorf("file not found")
		}
		l.Errorf("Failed to get tmpfile: %v", err)
		return 0, err
	}

	// 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
	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
}