// Copyright 2025 The Gogs Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.

package database

import (
	"context"

	"github.com/pkg/errors"

	"gogs.io/gogs/internal/gpgutil"
)

// VerifyCommitSignature verifies a commit signature against the user's GPG keys.
// It returns verification information including whether the signature is valid.
func (db *DB) VerifyCommitSignature(ctx context.Context, commitContent string, authorEmail string) (*gpgutil.CommitVerification, error) {
	// Extract signature from commit
	signature, payload, hasSig := gpgutil.ExtractSignature(commitContent)
	if !hasSig {
		return &gpgutil.CommitVerification{
			Verified: false,
			Reason:   "no signature",
		}, nil
	}

	// Find user by email
	user, err := db.Users().GetByEmail(ctx, authorEmail)
	if err != nil {
		return &gpgutil.CommitVerification{
			Verified: false,
			Reason:   "user not found",
		}, nil
	}

	// Get all GPG keys for the user
	keys, err := db.GPGKeys().List(ctx, user.ID)
	if err != nil {
		return nil, errors.Wrap(err, "list GPG keys")
	}

	if len(keys) == 0 {
		return &gpgutil.CommitVerification{
			Verified: false,
			Reason:   "no GPG keys found",
		}, nil
	}

	// Create keyring from user's GPG keys
	var armoredKeys []string
	for _, key := range keys {
		if key.CanSign && !key.IsExpired() {
			armoredKeys = append(armoredKeys, key.Content)
		}
	}

	if len(armoredKeys) == 0 {
		return &gpgutil.CommitVerification{
			Verified: false,
			Reason:   "no valid signing keys found",
		}, nil
	}

	keyring, err := gpgutil.CreateKeyring(armoredKeys)
	if err != nil {
		return nil, errors.Wrap(err, "create keyring")
	}

	// Verify the signature
	verification, err := gpgutil.VerifyCommitSignature(signature, payload, keyring)
	if err != nil {
		return nil, errors.Wrap(err, "verify signature")
	}

	return verification, nil
}