package main

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

// store is a password-store directory ($PASSWORD_STORE_DIR or ~/.password-store)
// whose entries are `<name>.gpg` binary OpenPGP files. It is layout-compatible
// with GnuPG `pass`; the only difference is that `.gpg-id` holds a Vault key
// reference ("<mount>/<key>") instead of a GPG fingerprint.
type store struct {
	dir string
}

func openStore() (*store, error) {
	dir := os.Getenv("PASSWORD_STORE_DIR")
	if dir == "" {
		home, err := os.UserHomeDir()
		if err != nil {
			return nil, err
		}
		dir = filepath.Join(home, ".password-store")
	}
	return &store{dir: dir}, nil
}

func (s *store) entryPath(name string) string {
	return filepath.Join(s.dir, name+".gpg")
}

func (s *store) hasEntry(name string) bool {
	fi, err := os.Stat(s.entryPath(name))
	return err == nil && !fi.IsDir()
}

func (s *store) isDir(name string) bool {
	fi, err := os.Stat(filepath.Join(s.dir, name))
	return err == nil && fi.IsDir()
}

// vaultRef walks up from an entry's directory to the store root and returns the
// governing Vault key reference, mirroring pass's per-subtree recipient
// resolution. It prefers a `.vault-id` file — which lets a dual-mode store keep
// real GPG fingerprints in `.gpg-id` (for plain `pass`) and the Vault ref here —
// and otherwise falls back to a `.gpg-id` that itself holds the Vault ref (a
// passv-native store).
func (s *store) vaultRef(name string) (string, error) {
	if ref, ok := s.lookupUp(name, ".vault-id"); ok {
		return ref, nil
	}
	if ref, ok := s.lookupUp(name, ".gpg-id"); ok {
		if _, _, err := splitRef(ref); err == nil {
			return ref, nil
		}
		return "", fmt.Errorf(".gpg-id holds a GPG id, not a Vault ref; add a .vault-id containing <mount>/<key> to read this store with passv")
	}
	return "", fmt.Errorf("password store is not initialized (no .gpg-id / .vault-id); run `passv init <mount>/<key>`")
}

// lookupUp returns the first non-empty line of the nearest `file` at or above
// the entry's directory.
func (s *store) lookupUp(name, file string) (string, bool) {
	dir := filepath.Dir(s.entryPath(name))
	for {
		if b, err := os.ReadFile(filepath.Join(dir, file)); err == nil {
			for _, line := range strings.Split(string(b), "\n") {
				if line = strings.TrimSpace(line); line != "" {
					return line, true
				}
			}
		}
		if dir == s.dir {
			return "", false
		}
		parent := filepath.Dir(dir)
		if parent == dir {
			return "", false
		}
		dir = parent
	}
}

// readCipher returns the raw bytes of an entry's `.gpg` file.
func (s *store) readCipher(name string) ([]byte, error) {
	return os.ReadFile(s.entryPath(name))
}

// writeCipher writes an entry, creating parent directories as needed.
func (s *store) writeCipher(name string, data []byte) error {
	p := s.entryPath(name)
	if err := os.MkdirAll(filepath.Dir(p), 0o700); err != nil {
		return err
	}
	return os.WriteFile(p, data, 0o600)
}

// list returns the entry names (without the .gpg suffix) under sub, recursively.
func (s *store) list(sub string) ([]string, error) {
	root := filepath.Join(s.dir, sub)
	var names []string
	err := filepath.WalkDir(root, func(path string, d os.DirEntry, err error) error {
		if err != nil {
			return err
		}
		base := d.Name()
		if d.IsDir() {
			if base == ".git" || (path != root && strings.HasPrefix(base, ".")) {
				return filepath.SkipDir
			}
			return nil
		}
		if !strings.HasSuffix(base, ".gpg") {
			return nil
		}
		rel, _ := filepath.Rel(s.dir, path)
		names = append(names, strings.TrimSuffix(rel, ".gpg"))
		return nil
	})
	sort.Strings(names)
	return names, err
}

// --- git integration (optional; the store may or may not be a git repo) ---

func (s *store) isGit() bool {
	fi, err := os.Stat(filepath.Join(s.dir, ".git"))
	return err == nil && (fi.IsDir() || fi.Mode().IsRegular())
}

// gitPassthrough runs `git -C <store> ...` with inherited stdio (for `passv git`).
func (s *store) gitPassthrough(args []string) error {
	cmd := exec.Command("git", append([]string{"-C", s.dir}, args...)...)
	cmd.Stdin, cmd.Stdout, cmd.Stderr = os.Stdin, os.Stdout, os.Stderr
	return cmd.Run()
}

// commit stages everything and commits, quietly, when the store is a git repo.
func (s *store) commit(msg string) {
	if !s.isGit() {
		return
	}
	_ = exec.Command("git", "-C", s.dir, "add", "-A").Run()
	// Nothing staged (e.g. content unchanged) is not an error worth surfacing.
	_ = exec.Command("git", "-C", s.dir, "commit", "-q", "-m", msg).Run()
}