//
//  MastodonController+Push.swift
//  Tusker
//
//  Created by Shadowfacts on 4/9/24.
//  Copyright © 2024 Shadowfacts. All rights reserved.
//

import Foundation
import Pachyderm
import PushNotifications
import CryptoKit

extension MastodonController {
    func createPushSubscription(subscription: PushNotifications.PushSubscription) async throws -> Pachyderm.PushSubscription {
        let req = Pachyderm.PushSubscription.create(
            endpoint: subscription.endpoint,
            // mastodon docs just say "Base64 encoded string of a public key from a ECDH keypair using the prime256v1 curve."
            // other apps use SecKeyCopyExternalRepresentation which is documented to use X9.63 for elliptic curve keys
            // and that seems to work
            publicKey: subscription.secretKey.publicKey.x963Representation,
            authSecret: subscription.authSecret,
            alerts: .init(subscription.alerts),
            policy: .init(subscription.policy)
        )
        return try await run(req).0
    }
    
    func updatePushSubscription(subscription: PushNotifications.PushSubscription) async throws -> Pachyderm.PushSubscription {
        // when updating anything other than the alerts/policy, we need to go through the create route
        return try await createPushSubscription(subscription: subscription)
    }

    func updatePushSubscription(alerts: PushNotifications.PushSubscription.Alerts, policy: PushNotifications.PushSubscription.Policy) async throws -> Pachyderm.PushSubscription {
        let req = Pachyderm.PushSubscription.update(alerts: .init(alerts), policy: .init(policy))
        var result = try await run(req).0
        if instanceFeatures.pushNotificationPolicyMissingFromResponse {
            // see https://github.com/mastodon/mastodon/issues/23145
            // so just assume if the request was successful that it worked
            result.policy = .init(policy)
        }
        return result
    }
    
    func deletePushSubscription() async throws {
        let req = Pachyderm.PushSubscription.delete()
        _ = try await run(req)
    }
}

private extension Pachyderm.PushSubscription.Alerts {
    init(_ alerts: PushNotifications.PushSubscription.Alerts) {
        self.init(
            mention: alerts.contains(.mention),
            status: alerts.contains(.status),
            reblog: alerts.contains(.reblog),
            follow: alerts.contains(.follow),
            followRequest: alerts.contains(.followRequest),
            favourite: alerts.contains(.favorite),
            poll: alerts.contains(.poll),
            update: alerts.contains(.update),
            emojiReaction: alerts.contains(.emojiReaction)
        )
    }
}

private extension Pachyderm.PushSubscription.Policy {
    init(_ policy: PushNotifications.PushSubscription.Policy) {
        switch policy {
        case .all:
            self = .all
        case .followers:
            self = .followers
        case .followed:
            self = .followed
        }
    }
}