// Package plain implements a plaintext backend
package plain

import (
	"context"
	"fmt"
	"runtime"
	"strings"
	"time"

	"github.com/blang/semver/v4"
	"github.com/gopasspw/gopass/internal/backend/crypto/gpg"
	"github.com/gopasspw/gopass/pkg/debug"
)

var staticPrivateKeyList = gpg.KeyList{
	gpg.Key{
		KeyType:      "rsa",
		KeyLength:    2048,
		Validity:     "u",
		CreationDate: time.Now(),
		Fingerprint:  "000000000000000000000000DEADBEEF",
		Identities: map[string]gpg.Identity{
			"Dead Beef <dead.beef@example.com>": {
				Name:         "Dead Beef",
				Email:        "dead.beef@example.com",
				CreationDate: time.Now(),
			},
		},
	},
	gpg.Key{
		KeyType:      "rsa",
		KeyLength:    2048,
		Validity:     "u",
		CreationDate: time.Now(),
		Fingerprint:  "000000000000000000000000FEEDBEEF",
		Identities: map[string]gpg.Identity{
			"Feed Beef <feed.beef@example.com>": {
				Name:         "Feed Beef",
				Email:        "feed.beef@example.com",
				CreationDate: time.Now(),
			},
		},
	},
}

// Mocker is a no-op GPG mock.
type Mocker struct{}

// New creates a new GPG mock.
func New() *Mocker {
	return &Mocker{}
}

// ListRecipients does nothing.
func (m *Mocker) ListRecipients(context.Context) ([]string, error) {
	return staticPrivateKeyList.Recipients(), nil
}

// FindRecipients does nothing.
func (m *Mocker) FindRecipients(ctx context.Context, keys ...string) ([]string, error) {
	rs := staticPrivateKeyList.Recipients()
	res := make([]string, 0, len(rs))
	for _, r := range rs {
		for _, needle := range keys {
			debug.V(1).Log("checking recipient %q = %q", r, needle)
			if strings.HasSuffix(r, needle) {
				res = append(res, r)
			}
		}
	}

	return res, nil
}

// ListIdentities does nothing.
func (m *Mocker) ListIdentities(context.Context) ([]string, error) {
	return staticPrivateKeyList.Recipients(), nil
}

// FindIdentities does nothing.
func (m *Mocker) FindIdentities(ctx context.Context, keys ...string) ([]string, error) {
	return m.FindRecipients(ctx, keys...)
}

// RecipientIDs does nothing.
func (m *Mocker) RecipientIDs(context.Context, []byte) ([]string, error) {
	return staticPrivateKeyList.Recipients(), nil
}

// Encrypt writes the input to disk unaltered.
func (m *Mocker) Encrypt(ctx context.Context, content []byte, recipients []string) ([]byte, error) {
	return content, nil
}

// Decrypt read the file from disk unaltered.
func (m *Mocker) Decrypt(ctx context.Context, ciphertext []byte) ([]byte, error) {
	return ciphertext, nil
}

// ImportPublicKey does nothing.
func (m *Mocker) ImportPublicKey(context.Context, []byte) error {
	return nil
}

// Version returns dummy version info.
func (m *Mocker) Version(context.Context) semver.Version {
	return debug.ModuleVersion("github.com/gopasspw/gopass/internal/backend/crypto/plain")
}

// Binary always returns 'gpg'.
func (m *Mocker) Binary() string {
	return "gpg"
}

// GenerateIdentity is not implemented.
func (m *Mocker) GenerateIdentity(ctx context.Context, name, email, pw string) (string, error) {
	return "", fmt.Errorf("not yet implemented")
}

// Fingerprint returns thd id.
func (m *Mocker) Fingerprint(ctx context.Context, id string) string {
	return id
}

// FormatKey returns the id.
func (m *Mocker) FormatKey(ctx context.Context, id, tpl string) string {
	return id
}

// Initialized returns nil.
func (m *Mocker) Initialized(context.Context) error {
	return nil
}

// Name returns plain, the name of the backend.
func (m *Mocker) Name() string {
	return Name
}

// Ext returns gpg.
func (m *Mocker) Ext() string {
	return Ext
}

const (
	// Name is the name of this backend.
	Name = "plain"
	// Ext is the file extension used by this backend.
	Ext = "txt"
	// IDFile is the name of the recipients file used by this backend.
	IDFile = ".plain-id"
)

// IDFile returns the name of the recipients file.
func (m *Mocker) IDFile() string {
	return IDFile
}

// ReadNamesFromKey does nothing.
func (m *Mocker) ReadNamesFromKey(ctx context.Context, buf []byte) ([]string, error) {
	return []string{"unsupported"}, nil
}

// GetFingerprint returns an empty fingerprint.
func (m *Mocker) GetFingerprint(ctx context.Context, key []byte) (string, error) {
	return "", nil
}

// Concurrency returns the number of CPUs.
func (m *Mocker) Concurrency() int {
	return runtime.NumCPU()
}

// String implements fmt.Stringer.
func (m *Mocker) String() string {
	return "Plaintext(Encrypt/Decrypt no-op)"
}