//
//  NextcloudApi.swift
//  Nextcloud Cookbook iOS Client
//
//  Created by Vincent Meilinger on 16.11.23.
//

import Foundation
import SwiftUI

/// The `NextcloudApi` class provides functionalities to interact with the Nextcloud API, particularly for user authentication.
class NextcloudApi {
    
    /// Initiates the login process with Nextcloud using the Login Flow v2.
    ///
    /// This static function sends a POST request to the Nextcloud server to obtain a `LoginV2Request` object.
    /// The object contains necessary details for the second step of the authentication process.
    ///
    /// - Returns: A tuple containing an optional `LoginV2Request` and an optional `NetworkError`.
    ///   - `LoginV2Request?`: An object containing the necessary information for the second step of the login process, if successful.
    ///   - `NetworkError?`: An error encountered during the network request, if any.

    static func loginV2Request(_ baseAddress: String) async -> (LoginV2Request?, NetworkError?) {
        let request = ApiRequest(
            path: baseAddress + "/index.php/login/v2",
            method: .POST
        )
        
        let (data, error) = await request.send(pathCompletion: false)
        
        if let error = error {
            return (nil, error)
        }
        guard let data = data else {
            return (nil, NetworkError.dataError)
        }
        guard let loginRequest: LoginV2Request = JSONDecoder.safeDecode(data) else {
            return (nil, NetworkError.decodingFailed)
        }
        return (loginRequest, nil)
    }
    
    /// Completes the user authentication process with Nextcloud using the Login Flow v2.
    ///
    /// This static function sends a POST request to the Nextcloud server with the login token obtained from `loginV2Request`.
    /// On successful validation of the token, it returns a `LoginV2Response` object, completing the user login.
    ///
    /// - Parameter req: A `LoginV2Request` object containing the token and endpoint information for the authentication request.
    ///
    /// - Returns: A tuple containing an optional `LoginV2Response` and an optional `NetworkError`.
    ///   - `LoginV2Response?`: An object representing the response of the login process, if successful.
    ///   - `NetworkError?`: An error encountered during the network request, if any.

    static func loginV2Poll(pollURL: String, pollToken: String) async -> (LoginV2Response?, NetworkError?) {
        let request = ApiRequest(
            path: pollURL,
            method: .POST,
            headerFields: [
                HeaderField.ocsRequest(value: true),
                HeaderField.accept(value: .JSON),
                HeaderField.contentType(value: .FORM)
            ],
            body: "token=\(pollToken)".data(using: .utf8)
        )
        let (data, error) = await request.send(pathCompletion: false)
        
        if let error = error {
            return (nil, error)
        }
        guard let data = data else {
            return (nil, NetworkError.dataError)
        }
        guard let loginResponse: LoginV2Response = JSONDecoder.safeDecode(data) else {
            return (nil, NetworkError.decodingFailed)
        }
        return (loginResponse, nil)
    }
    
    static func getAvatar() async -> (UIImage?, NetworkError?) {
        let request = ApiRequest(
            path: "/index.php/avatar/\(UserSettings.shared.username)/100",
            method: .GET,
            authString: UserSettings.shared.authString,
            headerFields: [HeaderField.ocsRequest(value: true), HeaderField.accept(value: .IMAGE)]
        )
        
        let (data, error) = await request.send()
        guard let data = data else { return (nil, error) }
        return (UIImage(data: data), error)
    }
    
    static func getHoverCard() async -> (UserData?, NetworkError?) {
        let request = ApiRequest(
            path: "/ocs/v2.php/hovercard/v1/\(UserSettings.shared.username)",
            method: .GET,
            authString: UserSettings.shared.authString,
            headerFields: [HeaderField.ocsRequest(value: true), HeaderField.accept(value: .JSON)]
        )
        
        let (data, error) = await request.send()
        guard let data = data else { return (nil, error) }
        do {
            let json = try JSONSerialization.jsonObject(with: data, options: []) as? [String: Any]
            let data = (json?["ocs"] as? [String: Any])?["data"] as? [String: Any]
            let userData = UserData(
                userId: data?["userId"] as? String ?? "",
                userDisplayName: data?["displayName"] as? String ?? ""
            )
            print(userData)
            return (userData, nil)
        } catch {
            print(error.localizedDescription)
            return (nil, NetworkError.decodingFailed)
        }
    }
}

struct UserData {
    let userId: String
    let userDisplayName: String
}