package logic

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

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

	"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) {
	var coverID sql.NullInt64

	// If cover image key is provided, move it from tmpfiles to files table
	if req.CoverImageKey != "" {
		// 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()

		// Get the tmpfile record
		var fileName string
		tmpQuery := `SELECT file_name FROM tmpfiles WHERE key = $1`
		err = tx.QueryRowContext(l.ctx, tmpQuery, req.CoverImageKey).Scan(&fileName)
		if err != nil {
			if err == sql.ErrNoRows {
				l.Errorf("Cover image not found in tmpfiles with key: %s", req.CoverImageKey)
				return nil, fmt.Errorf("cover image not found")
			}
			l.Errorf("Failed to get tmpfile: %v", err)
			return nil, err
		}

		// Get old cover_id to delete later
		var oldCoverID sql.NullInt64
		oldCoverQuery := `SELECT cover_id FROM posts WHERE id = $1`
		err = tx.QueryRowContext(l.ctx, oldCoverQuery, 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 old cover: %v", err)
			return nil, err
		}

		// Insert into files table
		fileQuery := `INSERT INTO files (file_name, file_key) VALUES ($1, $2) RETURNING id`
		err = tx.QueryRowContext(l.ctx, fileQuery, fileName, req.CoverImageKey).Scan(&coverID.Int64)
		if err != nil {
			l.Errorf("Failed to insert file record: %v", err)
			return nil, err
		}
		coverID.Valid = true

		// Delete from tmpfiles
		deleteQuery := `DELETE FROM tmpfiles WHERE key = $1`
		_, err = tx.ExecContext(l.ctx, deleteQuery, req.CoverImageKey)
		if err != nil {
			l.Errorf("Failed to delete tmpfile: %v", err)
			return nil, err
		}

		// Update post
		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
		if oldCoverID.Valid {
			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
			}
		}

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

		return &types.EditPostResp{}, nil
	}

	// No new cover image - just update the post
	query := `UPDATE posts SET title = $1, content = $2, updated_at = CURRENT_TIMESTAMP WHERE id = $3`
	result, err := l.svcCtx.DB.ExecContext(l.ctx, query, req.Title, req.Content, req.PostId)
	if err != nil {
		l.Errorf("Failed to update post: %v", err)
		return nil, err
	}

	// Check if post exists
	rowsAffected, err := result.RowsAffected()
	if err != nil {
		l.Errorf("Failed to get rows affected: %v", err)
		return nil, err
	}
	if rowsAffected == 0 {
		l.Errorf("Post not found with id: %s", req.PostId)
		return nil, fmt.Errorf("post not found")
	}

	return &types.EditPostResp{}, nil
}