package backup

import (
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strings"

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

	"gitocean/internal/model"
)

func Create(cfg model.ServerConfig, file string) error {
	tmp, err := os.MkdirTemp("", "gitocean-backup-*")
	if err != nil {
		return err
	}
	defer os.RemoveAll(tmp)
	metadata := filepath.Join(tmp, "metadata.sql")
	mysqlArgs, dbName, err := MySQLCLIArgs(cfg.MySQLDSN)
	if err != nil {
		return err
	}
	cmd := exec.Command("mysqldump", append(mysqlArgs, dbName)...)
	out, err := cmd.Output()
	if err != nil {
		return fmt.Errorf("mysqldump failed: %w", err)
	}
	if err := os.WriteFile(metadata, out, 0600); err != nil {
		return err
	}
	cmd = exec.Command("tar", "-czf", file, "-C", ".", cfg.Storage, "-C", tmp, "metadata.sql")
	cmd.Stdout, cmd.Stderr = os.Stdout, os.Stderr
	return cmd.Run()
}

func Restore(cfg model.ServerConfig, file string) error {
	tmp, err := os.MkdirTemp("", "gitocean-restore-*")
	if err != nil {
		return err
	}
	defer os.RemoveAll(tmp)
	cmd := exec.Command("tar", "-xzf", file, "-C", tmp)
	cmd.Stdout, cmd.Stderr = os.Stdout, os.Stderr
	if err := cmd.Run(); err != nil {
		return err
	}
	mysqlArgs, dbName, err := MySQLCLIArgs(cfg.MySQLDSN)
	if err != nil {
		return err
	}
	metadata := filepath.Join(tmp, "metadata.sql")
	f, err := os.Open(metadata)
	if err != nil {
		return err
	}
	defer f.Close()
	cmd = exec.Command("mysql", append(mysqlArgs, dbName)...)
	cmd.Stdin = f
	cmd.Stdout, cmd.Stderr = os.Stdout, os.Stderr
	if err := cmd.Run(); err != nil {
		return err
	}
	return CopyDir(filepath.Join(tmp, cfg.Storage), cfg.Storage)
}

func MySQLCLIArgs(dsn string) ([]string, string, error) {
	cfg, err := mysql.ParseDSN(dsn)
	if err != nil {
		return nil, "", err
	}
	args := []string{}
	if cfg.User != "" {
		args = append(args, "-u"+cfg.User)
	}
	if cfg.Passwd != "" {
		args = append(args, "-p"+cfg.Passwd)
	}
	if cfg.Net == "tcp" && cfg.Addr != "" {
		host, port := cfg.Addr, ""
		if strings.Contains(cfg.Addr, ":") {
			host, port, _ = strings.Cut(cfg.Addr, ":")
		}
		if host != "" {
			args = append(args, "-h"+host)
		}
		if port != "" {
			args = append(args, "-P"+port)
		}
	} else if cfg.Net == "unix" && cfg.Addr != "" {
		args = append(args, "--socket", cfg.Addr)
	}
	return args, cfg.DBName, nil
}

func CopyDir(src, dst string) error {
	return filepath.Walk(src, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		rel, err := filepath.Rel(src, path)
		if err != nil {
			return err
		}
		to := filepath.Join(dst, rel)
		if info.IsDir() {
			return os.MkdirAll(to, info.Mode())
		}
		b, err := os.ReadFile(path)
		if err != nil {
			return err
		}
		return os.WriteFile(to, b, info.Mode())
	})
}