// Applies init.sql using the packaged sync defaults (build/sync.defaults.json).
package main

import (
	"database/sql"
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	_ "github.com/go-sql-driver/mysql"
)

type syncDefaults struct {
	Host     string `json:"host"`
	Port     int    `json:"port"`
	User     string `json:"user"`
	Password string `json:"password"`
	Database string `json:"database"`
}

func loadDefaults() syncDefaults {
	path := filepath.Join("build", "sync.defaults.json")
	raw, err := os.ReadFile(path)
	if err != nil {
		panic(err)
	}
	var c syncDefaults
	if err := json.Unmarshal(raw, &c); err != nil {
		panic(err)
	}
	if c.Port <= 0 {
		c.Port = 3306
	}
	return c
}

func dsn(c syncDefaults, withDB bool) string {
	db := ""
	if withDB {
		db = c.Database
	}
	return fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?multiStatements=false&charset=utf8mb4",
		c.User, c.Password, c.Host, c.Port, db)
}

func main() {
	cfg := loadDefaults()
	if len(os.Args) > 1 && os.Args[1] == "inspect" {
		inspect(cfg)
		return
	}
	raw, err := os.ReadFile("init.sql")
	if err != nil {
		panic(err)
	}
	db, err := sql.Open("mysql", dsn(cfg, false))
	if err != nil {
		panic(err)
	}
	defer db.Close()
	// init.sql 的升级段依赖会话变量（SET @sql / PREPARE），必须固定在同一连接上执行。
	db.SetMaxOpenConns(1)

	var kept []string
	for _, line := range strings.Split(string(raw), "\n") {
		if t := strings.TrimSpace(line); strings.HasPrefix(t, "--") {
			continue
		}
		kept = append(kept, line)
	}
	for _, stmt := range strings.Split(strings.Join(kept, "\n"), ";") {
		s := strings.TrimSpace(stmt)
		if s == "" {
			continue
		}
		if _, err := db.Exec(s); err != nil {
			fmt.Println("ERR:", err, "stmt:", s[:min(80, len(s))])
			os.Exit(1)
		}
	}
	var n int
	if err := db.QueryRow("SELECT COUNT(*) FROM " + cfg.Database + ".sync_settings").Scan(&n); err != nil {
		fmt.Println("verify failed:", err)
		os.Exit(1)
	}
	fmt.Println("ok, sync_settings rows:", n, "host:", cfg.Host)
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

func inspect(cfg syncDefaults) {
	db, err := sql.Open("mysql", dsn(cfg, true))
	if err != nil {
		panic(err)
	}
	defer db.Close()
	rows, err := db.Query("SELECT user_id, name, LENGTH(value), updated_at FROM sync_settings ORDER BY user_id, name")
	if err != nil {
		panic(err)
	}
	defer rows.Close()
	for rows.Next() {
		var uid int64
		var name, at string
		var n int
		if err := rows.Scan(&uid, &name, &n, &at); err != nil {
			panic(err)
		}
		fmt.Printf("user=%d name=%-12s bytes=%-6d at=%s\n", uid, name, n, at)
	}
}