// 临时诊断：对照测试列元信息查询的"参数版"与"内联版"，定位 42601。
package main

import (
	"database/sql"
	"fmt"
	"log"
	"strings"

	_ "github.com/jackc/pgx/v5/stdlib"

	"fashionapi/internal/config"
)

func main() {
	cfg, err := config.Load("")
	if err != nil {
		log.Fatalf("load config: %v", err)
	}
	db, err := sql.Open("pgx", cfg.Database.DSN())
	if err != nil {
		log.Fatalf("open: %v", err)
	}
	defer db.Close()
	if err := db.Ping(); err != nil {
		log.Fatalf("ping: %v", err)
	}

	base := `
		SELECT c.column_name,
		       c.udt_name,
		       (c.is_nullable = 'YES'),
		       COALESCE(c.column_default, ''),
		       (c.column_default LIKE 'nextval(%')
		FROM information_schema.columns c
		WHERE c.table_schema = 'public' AND c.table_name = %s
		ORDER BY c.ordinal_position`

	// (a) 参数版：用 $1
	paramQ := strings.Replace(base, "%s", "$1", 1)
	fmt.Println("=== (a) 参数版 $1 ===")
	testQ(db, paramQ, "brand")

	// (b) 内联版：把 'brand' 直接拼进 SQL（模拟 simple-protocol 内联）
	inlineQ := strings.Replace(base, "%s", "'brand'", 1)
	fmt.Println("=== (b) 内联版 'brand' ===")
	testQ(db, inlineQ)

	// (c) 去掉 LIKE 表达式的版本（用 is_identity 代替）
	noLike := `
		SELECT c.column_name,
		       c.udt_name,
		       (c.is_nullable = 'YES'),
		       COALESCE(c.column_default, ''),
		       (c.is_identity = 'YES')
		FROM information_schema.columns c
		WHERE c.table_schema = 'public' AND c.table_name = 'brand'
		ORDER BY c.ordinal_position`
	fmt.Println("=== (c) 去掉 LIKE 表达式版 ===")
	testQ(db, noLike)
}

func testQ(db *sql.DB, q string, args ...any) {
	rows, err := db.Query(q, args...)
	if err != nil {
		fmt.Printf("  ERROR: %v\n", err)
		// 尝试用 pgconn 解析 position
		var pgErr interface{ Error() string }
		_ = pgErr
		fmt.Printf("  raw err: %s\n", err.Error())
		return
	}
	cnt := 0
	for rows.Next() {
		cnt++
	}
	fmt.Printf("  OK rows=%d err=%v\n", cnt, rows.Err())
	rows.Close()
}