// Package cli: backup.go implements the `orca backup` and `orca restore`
// subcommands (P04, v0.11 milestone).
//
//	orca backup --out <path>   — create a signed tar.gz of ORCA_HOME
//	orca restore --in <path>   — restore a verified backup
//
// `backup` reads the master key at paths.MasterKeyPath() and backs up
// paths.Root() (ORCA_HOME). The tarball + HMAC-SHA256 signature are
// written to --out and --out+".sig". `restore` verifies the signature
// before extracting; with --force it overwrites a non-empty target.
package cli

import (
	"fmt"
	"os"
	"path/filepath"
	"time"

	"github.com/spf13/cobra"

	"git.cloudinit.dev/coreci/orca/internal/backup"
	"git.cloudinit.dev/coreci/orca/internal/paths"
	"git.cloudinit.dev/coreci/orca/internal/secrets"
)

var (
	backupOutPath    string
	restoreInPath    string
	restoreTargetDir string
	restoreForce     bool
	restoreDryRun    bool
)

// acquireBackupLock atomically creates an exclusive lock file at
// paths.ClusterDir()/backup.lock (REQ-156, P07 T4). Returns a release
// function that MUST be deferred (it removes the lock file). If the
// lock file already exists, returns an error "backup already in
// progress" — preventing two concurrent `orca backup` invocations
// from racing on the same ORCA_HOME (two tarballs being written from
// the same source tree could produce inconsistent archives). O_CREATE
// |O_EXCL is atomic under POSIX.
func acquireBackupLock() (func(), error) {
	lockPath := filepath.Join(paths.ClusterDir(), "backup.lock")
	if err := os.MkdirAll(filepath.Dir(lockPath), 0o755); err != nil {
		return nil, fmt.Errorf("create cluster dir for backup lock: %w", err)
	}
	f, err := os.OpenFile(lockPath, os.O_CREATE|os.O_EXCL|os.O_WRONLY, 0o600)
	if err != nil {
		if os.IsExist(err) {
			return nil, fmt.Errorf("backup already in progress (lock file %s exists; remove it if stale)", lockPath)
		}
		return nil, fmt.Errorf("acquire backup lock: %w", err)
	}
	_, _ = f.WriteString(fmt.Sprintf("pid=%d started=%s\n", os.Getpid(), time.Now().UTC().Format(time.RFC3339)))
	_ = f.Close()
	return func() { _ = os.Remove(lockPath) }, nil
}

var backupCmd = &cobra.Command{
	Use:   "backup",
	Short: "Create a signed tar.gz backup of ORCA_HOME",
	Long: `Create a signed tar.gz backup of ORCA_HOME (P04).

Walks ` + "`ORCA_HOME`" + ` recursively, excludes /run/orca/*, *.sock,
*.db-wal, *.db-shm, packs the rest into a tar.gz, and computes an
HMAC-SHA256 signature using the cluster master key. The tarball is
written to --out; the hex-encoded signature to --out + ".sig".`,
	Args: cobra.NoArgs,
	RunE: func(cmd *cobra.Command, args []string) error {
		mk, err := secrets.LoadMasterKey(paths.MasterKeyPath())
		if err != nil {
			return fmt.Errorf("load master key: %w", err)
		}
		// REQ-156 / P07 T4: acquire an exclusive backup lock so two
		// concurrent `orca backup` invocations don't race on the same
		// ORCA_HOME (producing interleaved / inconsistent archives).
		backupRelease, err := acquireBackupLock()
		if err != nil {
			return err
		}
		defer backupRelease()
		out := backupOutPath
		if out == "" {
			ts := time.Now().UTC().Format("20060102-150405")
			out = fmt.Sprintf("orca-backup-%s.tar.gz", ts)
		}
		opts := backup.BackupOptions{
			SourceDir:  paths.Root(),
			OutputPath: out,
			MasterKey:  mk,
		}
		if err := backup.Backup(opts); err != nil {
			return err
		}
		if jsonOutput {
			return printJSON(map[string]string{
				"path": out,
				"sig":  out + ".sig",
			})
		}
		fmt.Fprintf(cmd.OutOrStdout(), "✓ Backup written: %s (sig: %s)\n", out, out+".sig")
		return nil
	},
}

var restoreCmd = &cobra.Command{
	Use:   "restore",
	Short: "Restore ORCA_HOME from a verified signed backup",
	Long: `Restore ORCA_HOME from a verified signed backup (P04/P07).

Verifies the HMAC-SHA256 signature on --in (using the cluster master
key) before extracting. Reconciles with live state: refuses to clobber
running allocations unless --force is given (with --force, stops the
running allocs, extracts, then restarts them from the restored state).
With --dry-run, extracts to a temp dir and reports what WOULD be
restored without touching the real ORCA_HOME. Performs post-restore
verification (master key, namespace dirs, SQLite DBs) and records the
restore in the audit log.`,
	Args: cobra.NoArgs,
	RunE: func(cmd *cobra.Command, args []string) error {
		if restoreInPath == "" {
			return fmt.Errorf("--in is required")
		}
		mk, err := secrets.LoadMasterKey(paths.MasterKeyPath())
		if err != nil {
			return fmt.Errorf("load master key: %w", err)
		}
		target := restoreTargetDir
		if target == "" {
			target = paths.Root()
		}
		opts := RestoreOptions{
			InputPath: restoreInPath,
			TargetDir: target,
			MasterKey: mk,
			Force:     restoreForce,
			DryRun:    restoreDryRun,
		}
		return runRestore(cmd, opts)
	},
}

func init() {
	backupCmd.Flags().StringVar(&backupOutPath, "out", "", "output tarball path (default: orca-backup-<timestamp>.tar.gz in CWD)")
	restoreCmd.Flags().StringVar(&restoreInPath, "in", "", "input tarball path (required)")
	restoreCmd.Flags().StringVar(&restoreTargetDir, "target", "", "restore target dir (default: ORCA_HOME)")
	restoreCmd.Flags().BoolVar(&restoreForce, "force", false, "overwrite a non-empty target directory and stop+restart running allocs")
	restoreCmd.Flags().BoolVar(&restoreDryRun, "dry-run", false, "extract to a temp dir and report what would be restored without touching ORCA_HOME")
	rootCmd.AddCommand(backupCmd)
	rootCmd.AddCommand(restoreCmd)
}