package db

import (
	"context"

	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgconn"
	"github.com/jackc/pgx/v5/pgxpool"
)

var defaultClient *Client

type Executor interface {
	Exec(ctx context.Context, sql string, args ...any) (pgconn.CommandTag, error)
	Query(ctx context.Context, sql string, args ...any) (pgx.Rows, error)
	QueryRow(ctx context.Context, sql string, args ...any) pgx.Row
}

type Client struct {
	pool *pgxpool.Pool
	tx   pgx.Tx
}

// Init 初始化
func Init(pool *pgxpool.Pool) {
	defaultClient = &Client{pool: pool}
}

// New 创建会话
func New() *Client {
	return &Client{
		pool: defaultClient.pool,
	}
}

// 内部获取执行器（关键）
func (c *Client) exec() Executor {
	if c.tx != nil {
		return c.tx
	}
	return c.pool
}