WIP: Use functional programming

lib/constants/constants.dart

@@ -0,0 +1,8 @@
+class Constants {
+  const Constants._();
+
+  static const brewExecutable = 'brew';
+  static const brewInfoCmd = 'info';
+  static const brewListCmd = 'list';
+  static const brewUninstallCmd = 'uninstall';
+}

lib/exceptions/exceptions.dart

@@ -0,0 +1,40 @@
+abstract class BrewException {
+  String get message;
+}
+
+class ProcessLaunchException implements BrewException {
+  ProcessLaunchException(this.args, this.error);
+
+  final List<String> args;
+  final Object error;
+
+  @override
+  String get message => 'Cannot launch brew with args $args : $error';
+}
+
+class ProcessStdoutReadingException implements BrewException {
+  ProcessStdoutReadingException(this.error);
+
+  final Object error;
+
+  @override
+  String get message => 'Cannot parse process stdout : $error';
+}
+
+class ProcessStdoutLastException implements BrewException {
+  ProcessStdoutLastException(this.error);
+
+  final Object error;
+
+  @override
+  String get message => 'Cannot read last from stdout : $error';
+}
+
+class ProcessStdoutOnDoneException implements BrewException {
+  ProcessStdoutOnDoneException(this.error);
+
+  final Object error;
+
+  @override
+  String get message => 'Cannot wait for stdout to complete : $error';
+}

lib/features/commands/data/commands_repository.dart

@@ -1,7 +1,7 @@
 import 'dart:async';
 import 'dart:io';
 
-import 'package:brew_flutter/constants/brew_exe.dart';
+import 'package:brew_flutter/constants/constants.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 
 final brewCommandsRepositoryProvider =
@@ -12,7 +12,7 @@ class BrewCommandsRepository {
   late Process process;
 
   Future<void> launch(List<String> args) async {
-    process = await Process.start(kBrewExecutable, args);
+    process = await Process.start(Constants.brewExecutable, args);
     stdout = process.stdout.map(String.fromCharCodes);
   }
 

lib/features/info/data/info_repository.dart

@@ -1,11 +1,18 @@
 import 'dart:io';
 
-import 'package:brew_flutter/constants/brew_exe.dart';
+import 'package:brew_flutter/constants/constants.dart';
+import 'package:brew_flutter/exceptions/exceptions.dart';
 import 'package:brew_flutter/features/info/model/package_info.dart';
+import 'package:brew_flutter/utils/process.dart';
+import 'package:fpdart/fpdart.dart';
 
-Future<PackageInfo> runBrewInfo(String package) async {
-  final process = await Process.start(kBrewExecutable, ['info', package]);
-  return PackageInfo.fromRaw(
-    await process.stdout.map(String.fromCharCodes).join('\n'),
-  );
-}
+TaskEither<BrewException, PackageInfo> brewInfoTE(String package) =>
+    startProcessTask([Constants.brewInfoCmd, package])
+        .flatMap(_processStdoutTE)
+        .map(PackageInfo.fromRaw); // IMPURE
+
+TaskEither<BrewException, String> _processStdoutTE(Process process) =>
+    TaskEither.tryCatch(
+      () => process.stdout.map(String.fromCharCodes).join('\n'),
+      (err, __) => ProcessStdoutReadingException(err),
+    );

lib/features/info/model/package_info.dart

@@ -1,3 +1,5 @@
+typedef PackageName = String;
+
 class PackageInfo {
   PackageInfo({
     required this.name,
@@ -24,7 +26,7 @@ class PackageInfo {
     );
   }
 
-  final String name;
+  final PackageName name;
   final String version;
   final String description;
   final String url;

lib/features/info/state/info_provider.dart

@@ -1,7 +1,28 @@
 import 'package:brew_flutter/features/info/data/info_repository.dart';
 import 'package:brew_flutter/features/info/model/package_info.dart';
+import 'package:brew_flutter/features/info/state/info_state.dart';
+import 'package:fpdart/fpdart.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 
-final packageInfoProvider = FutureProvider.family<PackageInfo, String>(
-  (_, package) => runBrewInfo(package),
+class PackageInfoState extends StateNotifier<InfoState> {
+  PackageInfoState(this.packageName) : super(const InfoState.loading()) {
+    init();
+  }
+
+  final PackageName packageName;
+
+  Future<Unit> init() async {
+    state = const InfoState.loading();
+    final infoTask = brewInfoTE(packageName);
+    state = (await infoTask.run()).match(
+      (error) => InfoState.error(error.message),
+      InfoState.success,
+    );
+    return unit;
+  }
+}
+
+final packageInfoProvider =
+    StateNotifierProviderFamily<PackageInfoState, InfoState, PackageName>(
+  (_, packageName) => PackageInfoState(packageName),
 );

lib/features/info/state/info_state.dart

@@ -0,0 +1,11 @@
+import 'package:brew_flutter/features/info/model/package_info.dart';
+import 'package:freezed_annotation/freezed_annotation.dart';
+
+part 'info_state.freezed.dart';
+
+@freezed
+class InfoState with _$InfoState {
+  const factory InfoState.loading() = LoadingInfoState;
+  const factory InfoState.error(String string) = ErrorInfoState;
+  const factory InfoState.success(PackageInfo info) = SuccessInfoState;
+}