// Command dbtables 列出 dnf90.db 里的表，用来核对 GM 工具「是否 90CN 数据库」的判定。
//
// 用法:
//
//	go run ./cmd/scratch/dbtables -db <dnf90.db> [-like dnf_]
package main

import (
	"database/sql"
	"flag"
	"fmt"
	"os"
	"strings"

	_ "modernc.org/sqlite"
)

func main() {
	dbPath := flag.String("db", "", "dnf90.db 路径")
	like := flag.String("like", "", "只显示名字包含该子串的表")
	flag.Parse()
	if *dbPath == "" {
		fmt.Fprintln(os.Stderr, "需要 -db")
		os.Exit(2)
	}
	if _, err := os.Stat(*dbPath); err != nil {
		fmt.Fprintln(os.Stderr, "找不到数据库:", err)
		os.Exit(1)
	}
	// 只读 + 不建 WAL；用 mode=ro 让 SQLite 不尝试创建 -wal/-shm
	dsn := "file:" + *dbPath + "?mode=ro&_pragma=query_only(1)"
	db, err := sql.Open("sqlite", dsn)
	if err != nil {
		fmt.Fprintln(os.Stderr, "打开失败:", err)
		os.Exit(1)
	}
	defer db.Close()

	rows, err := db.Query("SELECT type, name FROM sqlite_master WHERE type IN ('table','view','trigger') ORDER BY type, name")
	if err != nil {
		fmt.Fprintln(os.Stderr, "查询 sqlite_master 失败:", err)
		os.Exit(1)
	}
	defer rows.Close()
	var tables, views, triggers []string
	for rows.Next() {
		var kind, name string
		if err := rows.Scan(&kind, &name); err != nil {
			fmt.Fprintln(os.Stderr, "扫描失败:", err)
			os.Exit(1)
		}
		if *like != "" && !strings.Contains(name, *like) {
			continue
		}
		if kind == "trigger" {
			triggers = append(triggers, name)
			continue
		}
		if kind == "view" {
			views = append(views, name)
		} else {
			tables = append(tables, name)
		}
	}
	fmt.Printf("表 %d 个:\n", len(tables))
	for _, name := range tables {
		fmt.Println("  " + name)
	}
	if len(triggers) > 0 {
		fmt.Printf("触发器 %d 个:\n", len(triggers))
		for _, name := range triggers {
			fmt.Println("  " + name)
		}
	}
	if len(views) > 0 {
		fmt.Printf("视图 %d 个:\n", len(views))
		for _, name := range views {
			fmt.Println("  " + name)
		}
	}
	// 写探测：这些对象是视图时，SQLite 只有在存在 INSTEAD OF 触发器时才能写。
	// 用 WHERE 0 + 回滚，确保不改任何数据，只验证「可写性」。
	for _, target := range []string{"dnf_characters", "dnf_inventory_items", "dnf_skills", "dnf_accounts"} {
		tx, err := db.Begin()
		if err != nil {
			fmt.Printf("探测 %-22s 无法开事务: %v\n", target, err)
			continue
		}
		_, execErr := tx.Exec("UPDATE " + target + " SET rowid = rowid WHERE 0")
		_ = tx.Rollback()
		if execErr != nil {
			fmt.Printf("探测 %-22s 可写=false  原因: %v\n", target, execErr)
		} else {
			fmt.Printf("探测 %-22s 可写=true\n", target)
		}
	}

	for _, want := range []string{"dnf_accounts", "dnf_characters", "accounts", "characters"} {
		var count int
		err := db.QueryRow("SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name=?", want).Scan(&count)
		if err != nil {
			fmt.Printf("检查 %s 失败: %v\n", want, err)
			continue
		}
		fmt.Printf("关键表 %-16s 存在=%v\n", want, count > 0)
	}
}