//
//  UnlockViewModel.swift
//  MyPass
//

import Foundation
import Combine
import MyPassCore

@MainActor
final class UnlockViewModel: ObservableObject {
    @Published var password: String = ""
    @Published var errorMessage: String?
    @Published var isUnlocking: Bool = false
    @Published var showFilePicker: Bool = false

    private let session: VaultSession
    private let bookmarkService: FileBookmarkService
    private let keychainStore: KeychainStore
    private let biometricService: BiometricAuthService

    private let keychainAccount = "masterPassword"

    init(
        session: VaultSession,
        bookmarkService: FileBookmarkService = .init(),
        keychainStore: KeychainStore = .init(accessGroup: "org.antiloop222.mypass"),
        biometricService: BiometricAuthService = .init()
    ) {
        self.session = session
        self.bookmarkService = bookmarkService
        self.keychainStore = keychainStore
        self.biometricService = biometricService
    }

    var canUseBiometrics: Bool {
        biometricService.isAvailable && keychainStore.exists(for: keychainAccount)
    }

    var hasVault: Bool { bookmarkService.hasBookmark }

    func unlockWithBiometrics() {
        Task {
            isUnlocking = true
            errorMessage = nil
            do {
                try await biometricService.authenticate(reason: "Unlock MyPass")
                let storedPassword = try keychainStore.load(for: keychainAccount)
                let url = try bookmarkService.resolveURL()
                defer { bookmarkService.stopAccess(url: url) }
                try session.unlock(url: url, password: storedPassword)
            } catch {
                errorMessage = error.localizedDescription
            }
            isUnlocking = false
        }
    }

    func unlockWithPassword() {
        Task {
            isUnlocking = true
            errorMessage = nil
            do {
                let url = try bookmarkService.resolveURL()
                defer { bookmarkService.stopAccess(url: url) }
                try session.unlock(url: url, password: password)
                try keychainStore.save(password: password, for: keychainAccount)
                password = ""
            } catch KDBXError.invalidPassword {
                errorMessage = "Incorrect password."
            } catch {
                errorMessage = error.localizedDescription
            }
            isUnlocking = false
        }
    }

    func openFile(url: URL) {
        do {
            try bookmarkService.save(url: url)
            // Don't attempt to unlock yet -- picking a file only saves the bookmark.
            // The view now shows the password field for the user to enter their password.
        } catch {
            errorMessage = error.localizedDescription
        }
    }
}