// Command vrtxsql 在 VRTX / MySQL / SQLite 三个库之间搬表:
// 结构、数据、索引、主键一起走, 任意方向任意两个库都能互转。
//
//	vrtxsql -from vrtx:/data/app.db    -to sqlite:/data/app.sqlite
//	vrtxsql -from sqlite:/data/app.db  -to vrtx:/data/app.db
//	vrtxsql -from mysql:root:pw@tcp(127.0.0.1:3306)/shop -to vrtx:/data/shop.db
//	vrtxsql -from mysql:root:pw@tcp(127.0.0.1:3306)/shop -to sqlite:/data/shop.sqlite
//	vrtxsql -from vrtx:/data/app.db -list        // 只看结构, 不搬
//
// DSN 的前缀决定库的种类, 冒号后面整段就是它的标识 (路径 / 连接串):
//
//	vrtx:<文件路径>
//	sqlite:<文件路径>
//	mysql:<user>:<pw>@tcp(<host>:<port>)/<db>?<参数>
package main

import (
	"flag"
	"fmt"
	"os"
	"strings"

	"git.ycl.pub/yl32940/TsDB2/migrate"
)

func main() {
	if err := run(os.Args[1:]); err != nil {
		fmt.Fprintln(os.Stderr, "vrtxsql:", err)
		os.Exit(1)
	}
}

type cliOptions struct {
	from          string
	to            string
	tables        string
	recreate      bool
	batch         int
	limit         uint64
	dryRun        bool
	noMeta        bool
	autoPK        bool
	loose         bool
	truncOversize bool
	keepGoing     bool
	list          bool
	verbose       bool
	forceInspect  bool
}

func run(args []string) error {
	var c cliOptions
	fs := flag.NewFlagSet("vrtxsql", flag.ContinueOnError)
	fs.StringVar(&c.from, "from", "", "源库 DSN (必填), 如 vrtx:/data/app.db")
	fs.StringVar(&c.to, "to", "", "目标库 DSN (必填), 如 sqlite:/data/app.sqlite")
	fs.StringVar(&c.tables, "tables", "", "只迁这些表 (逗号分隔); 空 = 全部")
	fs.BoolVar(&c.recreate, "recreate", false, "目标表已存在时先 DROP 再重建 (默认复用并追加)")
	fs.IntVar(&c.batch, "batch", 500, "每批写入的行数")
	fs.Uint64Var(&c.limit, "limit", 0, "每张表最多迁多少行 (0 = 不限, 便于试跑)")
	fs.BoolVar(&c.dryRun, "dry-run", false, "只读结构、不写数据")
	fs.BoolVar(&c.noMeta, "no-meta", false, "不向 SQL 侧写 __vrtx_meta 保真表 (放弃定长档位/索引类型的还原)")
	fs.BoolVar(&c.autoPK, "auto-pk", false, "源表没有整数主键时自动补 _id 列 (否则报错)")
	fs.BoolVar(&c.loose, "loose", false, "值装不进目标列时按引擎语义截断 (默认报错, 免得静默丢数据)")
	fs.BoolVar(&c.truncOversize, "truncate-oversize", false,
		"值超过单值上限 (16360 字节) 时截断并逐行报出 (默认报错; 明确的数据丢失)")
	fs.BoolVar(&c.keepGoing, "continue-on-error", false, "某张表失败时跳过它、继续迁其余表 (默认第一个错误就中止)")
	fs.BoolVar(&c.list, "list", false, "只打印源库的表结构, 不搬数据")
	fs.BoolVar(&c.forceInspect, "force-inspect", false, "抢救模式: VRTX 端头页校验失败仍只读打开 (写禁用), 供损坏库抢救数据")
	fs.BoolVar(&c.verbose, "v", false, "打印每张表的进度")
	fs.Usage = func() {
		fmt.Fprint(os.Stderr, "用法: vrtxsql -from <DSN> -to <DSN> [选项]\n\n选项:\n")
		fs.PrintDefaults()
		fmt.Fprint(os.Stderr, "\nDSN: vrtx:<路径> | sqlite:<路径> | mysql:<user>:<pw>@tcp(<host>:<port>)/<db>\n")
	}
	if err := fs.Parse(args); err != nil {
		return err
	}
	if c.from == "" {
		fs.Usage()
		return fmt.Errorf("缺少 -from")
	}
	if c.list {
		return listSchemas(c)
	}
	if c.to == "" {
		fs.Usage()
		return fmt.Errorf("缺少 -to")
	}
	if c.from == c.to {
		return fmt.Errorf("-from 与 -to 是同一个库")
	}
	const maxBatchRows = 50000 // 与 vrtxsqlweb 一致: 防 make([]Row,0,Batch) 预分配 OOM
	if c.batch > maxBatchRows {
		return fmt.Errorf("-batch 超过上限 %d", maxBatchRows)
	}

	opts := buildOptions(c)
	src, err := migrate.ParseDSN(c.from, opts)
	if err != nil {
		return err
	}
	defer src.Close()
	dst, err := migrate.ParseDSN(c.to, opts)
	if err != nil {
		return err
	}
	defer dst.Close()

	if opts.Recreate {
		fmt.Fprintf(os.Stderr, "提示: -recreate 会先删掉目标库里同名的表\n")
	}
	rep, runErr := migrate.Run(src.Src, dst.Dst, opts)
	printReport(rep)
	if runErr != nil {
		return runErr
	}
	fmt.Printf("完成: %s → %s, 共 %d 张表 / %d 行, 用时 %s\n",
		rep.From, rep.To, len(rep.Tables), rep.Rows, rep.Elapsed.Round(1e6))
	return nil
}

func buildOptions(c cliOptions) *migrate.Options {
	o := migrate.DefaultOptions()
	o.Create = true
	o.EmbedMeta = !c.noMeta
	o.StrictValue = !c.loose
	o.TruncateOversize = c.truncOversize
	o.Recreate = c.recreate
	o.Batch = c.batch
	o.Limit = c.limit
	o.DryRun = c.dryRun
	o.AutoPK = c.autoPK
	o.ContinueOnError = c.keepGoing
	o.Verbose = c.verbose
	o.ForceInspect = c.forceInspect
	if c.tables != "" {
		for _, t := range strings.Split(c.tables, ",") {
			if t = strings.TrimSpace(t); t != "" {
				o.Tables = append(o.Tables, t)
			}
		}
	}
	return o
}

// listSchemas 打印源库每张表的结构 (列 / 类型 / 主键 / 索引), 不碰目标库。
func listSchemas(c cliOptions) error {
	opts := buildOptions(c)
	src, err := migrate.ParseDSN(c.from, opts)
	if err != nil {
		return err
	}
	defer src.Close()

	tables, err := src.Src.Tables()
	if err != nil {
		return err
	}
	if len(tables) == 0 {
		fmt.Printf("%s 里没有表\n", src.Identity())
		return nil
	}
	fmt.Printf("源: %s (%s), 共 %d 张表\n", src.Identity(), src.Kind, len(tables))
	for _, name := range tables {
		if !opts.Wants(name) {
			continue
		}
		s, err := src.Src.Schema(name)
		if err != nil {
			fmt.Printf("\n表 %s: 读结构失败: %v\n", name, err)
			continue
		}
		fmt.Printf("\n%s", s.Describe())
	}
	return nil
}

func printReport(rep *migrate.Report) {
	if rep == nil || len(rep.Tables) == 0 {
		return
	}
	var ok, failed int
	for _, tr := range rep.Tables {
		fmt.Println(rep.Line(tr))
		if tr.Error != "" {
			failed++
		} else if !tr.Skipped {
			ok++
		}
	}
	if failed > 0 {
		fmt.Printf("—— %d 张成功, %d 张失败 (上面带 [失败] 的行就是没迁完的表)\n", ok, failed)
	}
}