BotZ_app/lib/utils/connection.dart

import 'package:http/http.dart';
import 'package:logger/logger.dart';
import 'dart:convert';


final log = Logger();
const defaultRoutes = {
  "login": "/api/login",
  "logout": "/api/logout",
  "checkin": "/api/checkin",
  "checkout": "/api/checkout",
  "movements": "/api/movements",
  "status": "/api/status",
  "ping": "/api/ping",
};


class Connection {
  // Connection constructor.
  Connection(this.username, this.password, this.baseAddress, [this.routes = defaultRoutes]);
  // baseAddress contains the base address to the BotZ server
  final Uri baseAddress;
  // Username is the username to autenticate against the foreign
  // service.
  final String username;
  // Password is the password to autenticate against the foreign
  // service.
  final String password;
  final Map<String, String> routes;
  // _stateCookie is private. It contains the HTTP state cookie
  // assigned by the server.
  String _cookies = "";
  bool _loggedIn = false;
  bool _checkedIn = false;

  void updateState(String cookies, bool loggedIn) {
    this._cookies = loggedIn ? cookies : "";
    this._loggedIn = loggedIn;
  }

  void updateMovement(bool checkedIn) => this._checkedIn = checkedIn;

  bool isLoggedIn() => this._loggedIn;

  bool isCheckedIn() => this._checkedIn;

  // Perform the login and obtain the cookie.
  void login() async {
    var targetUri = this.baseAddress.toString() + this.routes['login'];
    var payload = jsonEncode({
        "username": this.username,
        "password": this.password,
        });

    var resp = await post(
        targetUri,
        headers: {"Content-Type": "application/json"},
        body: payload,
        );

    log.d("[login] Post sent to: $targetUri");
    handleResponse(resp);
    var body = jsonDecode(resp.body);
    log.d("[login] Response: $body");
    this.updateState(resp.headers['cookies'], body['logged_in']);
  }

  // Perform the logout.
  void logout() async {
    var targetUri = this.baseAddress.toString() + this.routes['logout'];

    var resp = await post(
        targetUri,
        headers: {'cookies': this._cookies},
        );

    log.d("[logout] Post sent to: $targetUri");
    handleResponse(resp);
    var body = jsonDecode(resp.body);
    log.d("[logout] Response: $body");
    this.updateState(this._cookies, body['logged_in']);
  }

  // Perform the checkin if possible.
  void checkin() async {
    if (!this._loggedIn) {
      throw UnacceptableInvocationException("Not logged in");
    }
    if (this._checkedIn) {
      throw UnacceptableInvocationException("Yet checked in");
    }
    var targetUri = this.baseAddress.toString() + this.routes['checkin'];

    var resp = await post(
        targetUri,
        headers: {'cookies': this._cookies},
        );

    handleResponse(resp);
    var body = jsonDecode(resp.body);
    log.d("[checkin] Response: $body");
    this.updateMovement(body['checked_in']);
  }

  // Perform the checkout if possible.
  void checkout() async {
    if (!this._loggedIn) {
      throw UnacceptableInvocationException("Not logged in");
    }
    if (!this._checkedIn) {
      throw UnacceptableInvocationException("Not yet checked in");
    }
    var targetUri = this.baseAddress.toString() + this.routes['checkout'];

    var resp = await post(
        targetUri,
        headers: {'cookies': this._cookies},
        );

    handleResponse(resp);
    var body = jsonDecode(resp.body);
    log.d("[checkout] Response: $body");
    this.updateMovement(body['checked_in']);
  }

  // Query the server for the list of movements.
  Future<Map<String, String>> getMovements() async {
    if (!this._loggedIn) {
      throw UnacceptableInvocationException("Not logged in");
    }
    if (!this._checkedIn) {
      throw UnacceptableInvocationException("Not yet checked in");
    }
    var targetUri = this.baseAddress.toString() + this.routes['movements'];

    var resp = await get(
        targetUri,
        headers: {'cookies': this._cookies},
        );

    try {
      handleResponse(resp);
    } on NotFoundException {
      return {};
    }
    var body = jsonDecode(resp.body);
    Map<String, String> movements;
    for (var values in body['movements']) {
      movements[values['time']] = values['type'];
    }
    return movements;
  }
}


class UnauthorizedException implements ClientException {
  UnauthorizedException(this.uri);
  final String message = "Unauthorized";
  final Uri uri;
}


class NotFoundException implements ClientException {
  NotFoundException(this.uri);
  final String message = "Resource not found";
  final Uri uri;
}


class UnacceptableInvocationException implements Exception {
  UnacceptableInvocationException(this.message);
  final String message;
}


Response handleResponse(Response resp) {
  final c = resp.statusCode;
  if (c >= 200 && c < 400) {
  } else if (c == 401) {
    throw UnauthorizedException(resp.request.url);
  } else if (c == 404) {
    throw NotFoundException(resp.request.url);
  }else if (c >=400 || c < 500) {
    throw ClientException("Unexpected return code: $c", resp.request.url);
  } else if (c >= 500) {
    throw ClientException("Server error: $c", resp.request.url);
  }
  return resp;
}