//===----------------------------------------------------------------------===//
// Copyright © 2025-2026 Apple Inc. and the Containerization project authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//   https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//===----------------------------------------------------------------------===//

#if os(macOS)
#if canImport(FoundationEssentials)
import FoundationEssentials
#else
import Foundation
#endif
import Security  // [Nucleic vendored patch] SecKeychain*UserInteractionAllowed for prompt-free reads

/// Holds the result of a query to the keychain.
public struct KeychainQueryResult {
    public var username: String
    public var password: String
    public var modifiedDate: Date
    public var createdDate: Date
}

/// Type that facilitates interacting with the macOS keychain.
public struct KeychainQuery {
    public init() {}

    /// Save a value to the keychain.
    /// - Parameters:
    ///   - securityDomain: The security domain used to fetch keychain entries.
    ///   - accessGroup: If present, the access group used to fetch keychain entries.
    ///   - hostname: The hostname for the authenticating server.
    ///   - username: The username to present to the server.
    ///   - password: The password to present to the server.
    /// - Throws: An error if the keychain query fails or returns unexpected data.
    public func save(
        securityDomain: String,
        accessGroup: String? = nil,
        hostname: String,
        username: String,
        password: String
    ) throws {
        if try exists(securityDomain: securityDomain, accessGroup: accessGroup, hostname: hostname) {
            try delete(securityDomain: securityDomain, accessGroup: accessGroup, hostname: hostname)
        }

        guard let passwordEncoded = password.data(using: String.Encoding.utf8) else {
            throw Self.Error.invalidPasswordConversion
        }
        var query: [String: Any] = [
            kSecClass as String: kSecClassInternetPassword,
            kSecAttrSecurityDomain as String: securityDomain,
            kSecAttrServer as String: hostname,
            kSecAttrAccount as String: username,
            kSecValueData as String: passwordEncoded,
            kSecAttrAccessible as String: kSecAttrAccessibleAfterFirstUnlock,
            kSecAttrSynchronizable as String: false,
        ]
        if let accessGroup {
            query[kSecAttrAccessGroup as String] = accessGroup
        }

        var status = SecItemAdd(query as CFDictionary, nil)
        // [Nucleic vendored patch] `exists` above no longer prompts, so it can under-report an
        // item this process isn't trusted to read; an explicit `login` re-save then hits
        // `errSecDuplicateItem`. Deleting (no read authorization required) and retrying once keeps
        // re-login working without ever raising a Keychain panel.
        if status == errSecDuplicateItem {
            try delete(securityDomain: securityDomain, accessGroup: accessGroup, hostname: hostname)
            status = SecItemAdd(query as CFDictionary, nil)
        }
        guard status == errSecSuccess else { throw Self.Error.unhandledError(status: status) }
    }

    /// Delete a value from the keychain.
    /// - Parameters:
    ///   - securityDomain: The security domain used to fetch keychain entries.
    ///   - accessGroup: If present, the access group used to fetch keychain entries.
    ///   - hostname: The hostname for the authenticating server.
    /// - Throws: An error if the keychain query fails or returns unexpected data.
    public func delete(securityDomain: String, accessGroup: String? = nil, hostname: String) throws {
        var query: [String: Any] = [
            kSecClass as String: kSecClassInternetPassword,
            kSecAttrSecurityDomain as String: securityDomain,
            kSecAttrServer as String: hostname,
            kSecMatchLimit as String: kSecMatchLimitOne,
        ]
        if let accessGroup {
            query[kSecAttrAccessGroup as String] = accessGroup
        }
        let status = SecItemDelete(query as CFDictionary)
        guard status == errSecSuccess || status == errSecItemNotFound else {
            throw Self.Error.unhandledError(status: status)
        }
    }

    /// Retrieve a value from the keychain.
    /// - Parameters:
    ///   - securityDomain: The security domain used to fetch keychain entries.
    ///   - accessGroup: If present, the access group used to fetch keychain entries.
    ///   - hostname: The hostname for the authenticating server.
    /// - Returns: The keychain entry.
    /// - Throws: An error if the keychain query fails or returns unexpected data.
    public func get(securityDomain: String, accessGroup: String? = nil, hostname: String) throws -> KeychainQueryResult? {
        var query: [String: Any] = [
            kSecClass as String: kSecClassInternetPassword,
            kSecAttrSecurityDomain as String: securityDomain,
            kSecAttrServer as String: hostname,
            kSecReturnAttributes as String: true,
            kSecMatchLimit as String: kSecMatchLimitOne,
            kSecReturnData as String: true,
        ]
        if let accessGroup {
            query[kSecAttrAccessGroup as String] = accessGroup
        }
        var item: CFTypeRef?
        let status = Self.withoutInteractiveUI { SecItemCopyMatching(query as CFDictionary, &item) }
        let exists = try isQuerySuccessful(status)
        if !exists {
            return nil
        }

        guard let fetched = item as? [String: Any] else {
            throw Self.Error.unexpectedDataFetched
        }
        guard let data = fetched[kSecValueData as String] as? Data else {
            throw Self.Error.keyNotPresent(key: kSecValueData as String)
        }
        guard let password = String(data: data, encoding: String.Encoding.utf8) else {
            throw Self.Error.unexpectedDataFetched
        }
        guard let username = fetched[kSecAttrAccount as String] as? String else {
            throw Self.Error.keyNotPresent(key: kSecAttrAccount as String)
        }
        guard let modifiedDate = fetched[kSecAttrModificationDate as String] as? Date else {
            throw Self.Error.keyNotPresent(key: kSecAttrModificationDate as String)
        }
        guard let createdDate = fetched[kSecAttrCreationDate as String] as? Date else {
            throw Self.Error.keyNotPresent(key: kSecAttrCreationDate as String)
        }
        return KeychainQueryResult(
            username: username,
            password: password,
            modifiedDate: modifiedDate,
            createdDate: createdDate
        )
    }

    /// List all keychain entries for a domain.
    /// - Parameters:
    ///   - securityDomain: The security domain used to fetch keychain entries.
    ///   - accessGroup: If present, the access group used to fetch keychain entries.
    /// - Returns: An array of keychain metadata for each matching entry, or an empty array if none are found.
    /// - Throws: An error if the keychain query fails or returns unexpected data.
    public func list(securityDomain: String, accessGroup: String? = nil) throws -> [RegistryInfo] {
        var query: [String: Any] = [
            kSecClass as String: kSecClassInternetPassword,
            kSecAttrSecurityDomain as String: securityDomain,
            kSecReturnAttributes as String: true,
            kSecReturnData as String: false,
            kSecMatchLimit as String: kSecMatchLimitAll,
        ]
        if let accessGroup {
            query[kSecAttrAccessGroup as String] = accessGroup
        }
        var item: CFTypeRef?
        let status = Self.withoutInteractiveUI { SecItemCopyMatching(query as CFDictionary, &item) }
        let exists = try isQuerySuccessful(status)
        if !exists {
            return []
        }

        guard let fetched = item as? [[String: Any]] else {
            throw Self.Error.unexpectedDataFetched
        }

        return try fetched.map { registry in
            guard let hostname = registry[kSecAttrServer as String] as? String else {
                throw Self.Error.keyNotPresent(key: kSecAttrServer as String)
            }
            guard let username = registry[kSecAttrAccount as String] as? String else {
                throw Self.Error.keyNotPresent(key: kSecAttrAccount as String)
            }
            guard let modifiedDate = registry[kSecAttrModificationDate as String] as? Date else {
                throw Self.Error.keyNotPresent(key: kSecAttrModificationDate as String)
            }
            guard let createdDate = registry[kSecAttrCreationDate as String] as? Date else {
                throw Self.Error.keyNotPresent(key: kSecAttrCreationDate as String)
            }

            return RegistryInfo(
                hostname: hostname,
                username: username,
                modifiedDate: modifiedDate,
                createdDate: createdDate
            )
        }
    }

    /// Check if a value exists in the keychain.
    /// - Parameters:
    ///   - securityDomain: The security domain used to fetch keychain entries.
    ///   - accessGroup: If present, the access group used to fetch keychain entries.
    ///   - hostname: The hostname for the authenticating server.
    /// - Returns: `true` if the entry exists, `false` otherwise.
    /// - Throws: An error if the keychain query fails.
    public func exists(securityDomain: String, accessGroup: String? = nil, hostname: String) throws -> Bool {
        var query: [String: Any] = [
            kSecClass as String: kSecClassInternetPassword,
            kSecAttrSecurityDomain as String: securityDomain,
            kSecAttrServer as String: hostname,
            kSecReturnAttributes as String: true,
            kSecMatchLimit as String: kSecMatchLimitOne,
            kSecReturnData as String: false,
        ]
        if let accessGroup {
            query[kSecAttrAccessGroup as String] = accessGroup
        }

        let status = Self.withoutInteractiveUI { SecItemCopyMatching(query as CFDictionary, nil) }
        return try isQuerySuccessful(status)
    }

    private func isQuerySuccessful(_ status: Int32) throws -> Bool {
        // [Nucleic vendored patch] With interactive UI suppressed (see `withoutInteractiveUI`), a
        // matching item the caller isn't trusted to read returns `errSecInteractionNotAllowed`
        // instead of prompting. Treat it like "not found" so registry lookups degrade to anonymous
        // / env-var auth rather than surfacing an error — and never raise a Keychain panel.
        guard status != errSecItemNotFound, status != errSecInteractionNotAllowed else {
            return false
        }
        guard status == errSecSuccess else {
            throw Self.Error.unhandledError(status: status)
        }
        return true
    }

    /// [Nucleic vendored patch] Run `body` with the legacy login Keychain's interactive
    /// authorization panel disabled, restoring the prior setting afterward.
    ///
    /// Nucleic requires that no automatic registry-credential lookup (image pull / push / list, via
    /// `KeychainHelper`) can ever raise the macOS "<app> wants to use your confidential information
    /// stored in 'ghcr.io' in your keychain" panel. That panel appears whenever a process that isn't
    /// on an internet-password item's ACL reads it — e.g. a `cctl` binary re-signed ad-hoc by a fresh
    /// `make vminit-image` reading a token an earlier build stored. The data-protection
    /// `kSecUseAuthenticationUI*` flags do NOT govern that legacy ACL/partition-list dialog; the only
    /// switch that does is `SecKeychainSetUserInteractionAllowed(false)`, which makes a read that
    /// would otherwise prompt fail with `errSecInteractionNotAllowed`. An already-trusted item still
    /// reads silently; anything else fails silently and the caller falls back to anonymous / env-var
    /// auth. `SecKeychain*` is deprecated but remains the only API covering this panel. Mirrors
    /// `KeychainOwnedAccess.withoutLegacyKeychainUI` in NucleicCore.
    private static func withoutInteractiveUI<T>(_ body: () -> T) -> T {
        var previous = DarwinBoolean(true)
        SecKeychainGetUserInteractionAllowed(&previous)
        SecKeychainSetUserInteractionAllowed(false)
        defer { SecKeychainSetUserInteractionAllowed(previous.boolValue) }
        return body()
    }
}

extension KeychainQuery {
    public enum Error: Swift.Error {
        case unhandledError(status: Int32)
        case unexpectedDataFetched
        case keyNotPresent(key: String)
        case invalidPasswordConversion
    }
}
#endif