// Copyright © 2020 Metabolist. All rights reserved.

import Combine
import DB
import Foundation
import Mastodon
import MastodonAPI

public struct ProfileService {
    public let accountServicePublisher: AnyPublisher<AccountService, Error>

    private let id: Account.Id
    private let mastodonAPIClient: MastodonAPIClient
    private let contentDatabase: ContentDatabase

    init(account: Account, mastodonAPIClient: MastodonAPIClient, contentDatabase: ContentDatabase) {
        self.init(
            id: account.id,
            account: account,
            mastodonAPIClient: mastodonAPIClient,
            contentDatabase: contentDatabase)
    }

    init(id: Account.Id, mastodonAPIClient: MastodonAPIClient, contentDatabase: ContentDatabase) {
        self.init(id: id, account: nil, mastodonAPIClient: mastodonAPIClient, contentDatabase: contentDatabase)
    }

    private init(
        id: Account.Id,
        account: Account?,
        mastodonAPIClient: MastodonAPIClient,
        contentDatabase: ContentDatabase) {
        self.id = id
        self.mastodonAPIClient = mastodonAPIClient
        self.contentDatabase = contentDatabase

        var accountPublisher = contentDatabase.accountObservation(id: id)

        if let account = account {
            accountPublisher = accountPublisher
                .merge(with: Just(account).setFailureType(to: Error.self))
                .removeDuplicates()
                .eraseToAnyPublisher()
        }

        accountServicePublisher = accountPublisher
            .map { AccountService(account: $0, mastodonAPIClient: mastodonAPIClient, contentDatabase: contentDatabase) }
            .eraseToAnyPublisher()
    }
}

public extension ProfileService {
    func timelineService(profileCollection: ProfileCollection) -> TimelineService {
        TimelineService(
            timeline: .profile(accountId: id, profileCollection: profileCollection),
            mastodonAPIClient: mastodonAPIClient,
            contentDatabase: contentDatabase)
    }

    func fetchPinnedStatuses() -> AnyPublisher<Never, Error> {
        mastodonAPIClient.request(
            StatusesEndpoint.accountsStatuses(
                id: id,
                excludeReplies: true,
                onlyMedia: false,
                pinned: true))
            .flatMap { contentDatabase.insert(pinnedStatuses: $0, accountId: id) }
            .eraseToAnyPublisher()
    }
}