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

// Delete a blog post
func NewDeletePostLogic(ctx context.Context, svcCtx *svc.ServiceContext) *DeletePostLogic {
	return &DeletePostLogic{
		Logger: logx.WithContext(ctx),
		ctx:    ctx,
		svcCtx: svcCtx,
	}
}

func (l *DeletePostLogic) DeletePost(req *types.DeletePostReq) (resp *types.DeletePostResp, 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()

	// Get cover_id before deleting the post
	var coverID sql.NullInt64
	getCoverQuery := `SELECT cover_id FROM posts WHERE id = $1`
	err = tx.QueryRowContext(l.ctx, getCoverQuery, req.PostId).Scan(&coverID)
	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
	}

	// Delete hashtag associations (post_hashtags will be deleted by CASCADE)
	deleteHashtagsQuery := `DELETE FROM post_hashtags WHERE post_id = $1`
	_, err = tx.ExecContext(l.ctx, deleteHashtagsQuery, req.PostId)
	if err != nil {
		l.Errorf("Failed to delete hashtag associations: %v", err)
		return nil, err
	}

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

	// Delete cover file if exists
	if coverID.Valid {
		deleteFileQuery := `DELETE FROM files WHERE id = $1`
		_, err = tx.ExecContext(l.ctx, deleteFileQuery, coverID.Int64)
		if err != nil {
			l.Errorf("Failed to delete 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.DeletePostResp{}, nil
}