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

// Init 初始化（只调用一次）
func Init(pool *pgxpool.Pool) {
	defaultClient = &Client{pool: pool}
}

// New 获取全局 client
func New() *Client {
	if defaultClient == nil {
		panic("db not initialized, call db.Init(pool) first")
	}
	return defaultClient
}

func (c *Client) Exec(ctx context.Context, sql string, args ...any) (pgconn.CommandTag, error) {
	if c.tx != nil {
		return c.tx.Exec(ctx, sql, args...)
	}
	return c.pool.Exec(ctx, sql, args...)
}

func (c *Client) Query(ctx context.Context, sql string, args ...any) (pgx.Rows, error) {
	if c.tx != nil {
		return c.tx.Query(ctx, sql, args...)
	}
	return c.pool.Query(ctx, sql, args...)
}

func (c *Client) QueryRow(ctx context.Context, sql string, args ...any) pgx.Row {
	if c.tx != nil {
		return c.tx.QueryRow(ctx, sql, args...)
	}
	return c.pool.QueryRow(ctx, sql, args...)
}