import AVFoundation
import Combine
import Foundation
import GRDB
import Photos

@MainActor
final class ConversationStore: ObservableObject {
    @Published private(set) var messages: [Message] = []
    @Published var replyText = ""

    private(set) var roster: Roster
    private let client: Client

    private var messagesCancellable: AnyCancellable?

    init(roster: Roster, client: Client) {
        self.client = client
        self.roster = roster
        subscribe()
    }
}

extension ConversationStore {
    func sendMessage(_ message: String) async {
        var msg = Message.blank
        msg.from = roster.bareJid
        msg.to = roster.contactBareJid
        msg.body = message

        // store as pending on db, and send
        do {
            try await msg.save()
            try await client.sendMessage(msg)
            try await msg.setStatus(.sent)
        } catch {
            try? await msg.setStatus(.error)
        }
    }

    func sendContact(_ jidStr: String) async {
        await sendMessage("contact:\(jidStr)")
    }

    func sendLocation(_ lat: Double, _ lon: Double) async {
        await sendMessage("geo:\(lat),\(lon)")
    }

    private func upload(_ message: Message) async {
        do {
            try await message.setStatus(.pending)
            var message = message
            guard case .attachment(let attachment) = message.contentType else {
                throw ClientStoreError.invalidContentType
            }
            guard let localName = attachment.localPath else {
                throw ClientStoreError.invalidLocalName
            }
            let remotePath = try await client.uploadFile(localName)
            message.contentType = .attachment(
                Attachment(
                    type: attachment.type,
                    localName: attachment.localName,
                    thumbnailName: nil,
                    remotePath: remotePath
                )
            )
            message.body = remotePath
            message.oobUrl = remotePath
            try await message.save()
            try await client.sendMessage(message)
            try await message.setStatus(.sent)
        } catch {
            try? await message.setStatus(.error)
        }
    }

    func downloadAttachment(_ message: Message) async {
        guard case .attachment(let attachment) = message.contentType else {
            return
        }
        guard let remotePath = attachment.remotePath, let remoteUrl = URL(string: remotePath) else {
            return
        }
        do {
            let localName = "\(message.id)_\(UUID().uuidString).\(remoteUrl.lastPathComponent)"
            let localUrl = Const.fileFolder.appendingPathComponent(localName)

            // Download the file
            let (tempUrl, _) = try await URLSession.shared.download(from: remoteUrl)
            try FileManager.default.moveItem(at: tempUrl, to: localUrl)

            var message = message
            message.contentType = .attachment(
                Attachment(
                    type: attachment.type,
                    localName: localName,
                    thumbnailName: attachment.thumbnailName,
                    remotePath: remotePath
                )
            )
            try await message.save()
        } catch {
            logIt(.error, "Can't download attachment: \(error)")
        }
    }
}

extension ConversationStore {
    var contacts: [Roster] {
        get async {
            do {
                let rosters = try await Database.shared.dbQueue.read { db in
                    try Roster
                        .filter(Column("locallyDeleted") == false)
                        .fetchAll(db)
                }
                return rosters
            } catch {
                return []
            }
        }
    }
}

private extension ConversationStore {
    func subscribe() {
        messagesCancellable = ValueObservation.tracking(Message
            .filter(
                (Column("to") == roster.bareJid && Column("from") == roster.contactBareJid) ||
                    (Column("from") == roster.bareJid && Column("to") == roster.contactBareJid)
            )
            .order(Column("date").desc)
            .fetchAll
        )
        .publisher(in: Database.shared.dbQueue, scheduling: .immediate)
        .receive(on: DispatchQueue.main)
        .sink { _ in
        } receiveValue: { [weak self] messages in
            self?.messages = messages
        }
    }
}