OAuth Support (#53)

Rips out the old auth method, adds OAuth support. Fixes #51.

Tested Platforms:
- [x] Linux
    - [x] Flatpak
    - [x] Native (Nix)
- [x] Android
- [ ] Windows
- [ ] MacOS

Reviewed-on: Nexus/nexus#53

lib/models/requests/get_event.dart

@@ -2,9 +2,8 @@ import "package:freezed_annotation/freezed_annotation.dart";
 part "get_event.freezed.dart";
 part "get_event.g.dart";
 
-@Freezed()
+@freezed
 abstract class GetEventRequest with _$GetEventRequest {
-  const GetEventRequest._();
   const factory GetEventRequest({
     required String roomId,
     required String eventId,

lib/models/requests/login.dart

@@ -1,15 +0,0 @@
-import "package:freezed_annotation/freezed_annotation.dart";
-part "login.freezed.dart";
-part "login.g.dart";
-
-@freezed
-abstract class LoginRequest with _$LoginRequest {
-  const factory LoginRequest({
-    required String username,
-    required String password,
-    required String homeserverUrl,
-  }) = _LoginRequest;
-
-  factory LoginRequest.fromJson(Map<String, Object?> json) =>
-      _$LoginRequestFromJson(json);
-}

lib/models/requests/oauth/exchange_token.dart

@@ -0,0 +1,17 @@
+import "package:freezed_annotation/freezed_annotation.dart";
+part "exchange_token.freezed.dart";
+part "exchange_token.g.dart";
+
+@freezed
+abstract class OAuthExchangeTokenRequest with _$OAuthExchangeTokenRequest {
+  const factory OAuthExchangeTokenRequest({
+    required Uri homeserverUrl,
+    required String codeVerifier,
+    required Uri redirectUri,
+    required String code,
+    required String clientId,
+  }) = _OAuthExchangeTokenRequest;
+
+  factory OAuthExchangeTokenRequest.fromJson(Map<String, Object?> json) =>
+      _$OAuthExchangeTokenRequestFromJson(json);
+}

lib/models/requests/oauth/get_auth_url.dart

@@ -0,0 +1,43 @@
+import "dart:math";
+
+import "package:fast_immutable_collections/fast_immutable_collections.dart";
+import "package:freezed_annotation/freezed_annotation.dart";
+part "get_auth_url.freezed.dart";
+part "get_auth_url.g.dart";
+
+@freezed
+abstract class OAuthGetAuthUrl with _$OAuthGetAuthUrl {
+  const factory OAuthGetAuthUrl({
+    required ResponseMode responseMode,
+    required Uri homeserverUrl,
+    required Uri redirectUri,
+    required IList<String> scopes,
+    required String clientId,
+    String? userIdHint,
+  }) = _OAuthGetAuthUrl;
+
+  factory OAuthGetAuthUrl.fromJson(Map<String, Object?> json) =>
+      _$OAuthGetAuthUrlFromJson(json);
+}
+
+abstract class Scope {
+  static final openid = "openid";
+  static final email = "email";
+  static final clientApi = "urn:matrix:client:api:*";
+
+  static final _deviceChars = IList(
+    ("ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+            "abcdefghijklmnopqrstuvwxyz"
+            "0123456789"
+            "-._~")
+        .split(""),
+  );
+
+  static String get _deviceId =>
+      _deviceChars.shuffle(Random.secure()).sublist(0, 10).join();
+
+  static String get device => "urn:matrix:client:device:$_deviceId";
+}
+
+@JsonEnum(fieldRename: .snake)
+enum ResponseMode { query, fragment }

lib/models/requests/oauth/register_client.dart

@@ -0,0 +1,47 @@
+import "package:fast_immutable_collections/fast_immutable_collections.dart";
+import "package:freezed_annotation/freezed_annotation.dart";
+part "register_client.freezed.dart";
+part "register_client.g.dart";
+
+@freezed
+abstract class OAuthRegisterClientRequest with _$OAuthRegisterClientRequest {
+  const factory OAuthRegisterClientRequest({
+    required Uri homeserverUrl,
+    @Default(ApplicationType.web) ApplicationType applicationType,
+    String? clientName,
+    required Uri clientUri,
+    Uri? logoUri,
+    Uri? policyUri,
+    Uri? tosUri,
+    IList<GrantType>? grantTypes,
+    IList<Uri>? redirectUris,
+    IList<ResponseType>? responseTypes,
+    AuthMethod? authMethod,
+  }) = _OAuthRegisterClientRequest;
+
+  factory OAuthRegisterClientRequest.fromJson(Map<String, Object?> json) =>
+      _$OAuthRegisterClientRequestFromJson(json);
+}
+
+enum ApplicationType { native, web }
+
+@JsonEnum(fieldRename: .snake)
+enum ResponseType { code, idToken }
+
+@JsonEnum(fieldRename: .snake)
+enum AuthMethod {
+  clientSecretPost,
+  clientSecretBasic,
+  clientSecretJwt,
+  privateKeyJwt,
+  none,
+}
+
+@JsonEnum(fieldRename: .snake)
+enum GrantType {
+  authorizationCode,
+  refreshToken,
+  clientCredentials,
+  @JsonValue("urn:ietf:params:oauth:grant-type:device_code")
+  deviceCode,
+}