main.dart

//
// Copyright 2022-2023 Picovoice Inc.
//
// You may not use this file except in compliance with the license. A copy of the license is located in the "LICENSE"
// file accompanying this source.
//
// Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
// an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.
//

import 'dart:async';
import 'dart:convert';
import 'dart:io';

import 'package:flutter/material.dart';
import 'package:leopard_demo/mic_recorder.dart';
import 'package:leopard_flutter/leopard.dart';
import 'package:leopard_flutter/leopard_error.dart';
import 'package:leopard_flutter/leopard_transcript.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  final String accessKey =
      '{YOUR_ACCESS_KEY_HERE}'; // AccessKey obtained from Picovoice Console (https://console.picovoice.ai/)
  final int maxRecordingLengthSecs = 120;

  final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();

  bool isError = false;
  String errorMessage = "";

  bool isButtonDisabled = false;
  bool isRecording = false;
  bool isProcessing = false;
  double recordedLength = 0.0;
  String statusAreaText = "";
  String transcriptText = "";
  List<LeopardWord> words = [];

  MicRecorder? _micRecorder;
  Leopard? _leopard;

  @override
  void initState() {
    super.initState();
    setState(() {
      isButtonDisabled = true;
      recordedLength = 0.0;
      statusAreaText = "Initializing Leopard...";
      transcriptText = "";
      words = [];
    });

    initLeopard();
  }

  Future<void> initLeopard() async {
    String language = "";
    try {
      final paramsString =
          await DefaultAssetBundle.of(context).loadString('assets/params.json');
      final params = json.decode(paramsString);

      language = params["language"];
    } catch (_) {
      errorCallback(LeopardException(
          "Could not find `params.json`. Ensure 'prepare_demo.dart' script was run before launching the demo."));
      return;
    }

    final String suffix = language != "en" ? "_$language" : "";
    final String modelPath = "assets/models/leopard_params$suffix.pv";

    try {
      _leopard = await Leopard.create(accessKey,
          modelPath,
          enableAutomaticPunctuation: true,
          enableDiarization: true);
      _micRecorder = await MicRecorder.create(
          _leopard!.sampleRate, recordedCallback, errorCallback);
      setState(() {
        statusAreaText =
            "Press START to start recording some audio to transcribe";
        isButtonDisabled = false;
      });
    } on LeopardActivationException {
      errorCallback(LeopardActivationException("AccessKey activation error."));
    } on LeopardActivationLimitException {
      errorCallback(LeopardActivationLimitException(
          "AccessKey reached its device limit."));
    } on LeopardActivationRefusedException {
      errorCallback(LeopardActivationRefusedException("AccessKey refused."));
    } on LeopardActivationThrottledException {
      errorCallback(
          LeopardActivationThrottledException("AccessKey has been throttled."));
    } on LeopardException catch (ex) {
      errorCallback(ex);
    }
  }

  Future<void> recordedCallback(double length) async {
    if (length < maxRecordingLengthSecs) {
      setState(() {
        recordedLength = length;
        statusAreaText =
            "Recording : ${length.toStringAsFixed(1)} / $maxRecordingLengthSecs seconds";
      });
    } else {
      setState(() {
        isButtonDisabled = true;
        recordedLength = length;
        statusAreaText = "Transcribing, please wait...";
      });
      await _stopRecording();
    }
  }

  void errorCallback(LeopardException error) {
    setState(() {
      isError = true;
      errorMessage = error.message!;
    });
  }

  Future<void> _startRecording() async {
    if (isRecording || _micRecorder == null) {
      return;
    }

    try {
      await _micRecorder!.startRecord();
      setState(() {
        isRecording = true;
      });
    } on LeopardException catch (ex) {
      errorCallback(ex);
    }
  }

  Future<void> _stopRecording() async {
    if (!isRecording || _micRecorder == null) {
      return;
    }

    try {
      File recordedFile = await _micRecorder!.stopRecord();
      setState(() {
        statusAreaText = "Transcribing, please wait...";
        isRecording = false;
        isButtonDisabled = true;
      });
      _processAudio(recordedFile);
    } on LeopardException catch (ex) {
      errorCallback(ex);
    }
  }

  Future<void> _processAudio(File recordedFile) async {
    if (_leopard == null) {
      return;
    }

    Stopwatch stopwatch = Stopwatch()..start();
    LeopardTranscript? result = await _leopard?.processFile(recordedFile.path);
    Duration elapsed = stopwatch.elapsed;

    String audioLength = recordedLength.toStringAsFixed(1);
    String transcriptionTime =
        (elapsed.inMilliseconds / 1000).toStringAsFixed(1);

    setState(() {
      statusAreaText =
          "Transcribed $audioLength(s) of audio in $transcriptionTime(s)";
      transcriptText = result?.transcript ?? "";
      words = result?.words ?? [];
      isButtonDisabled = false;
    });
  }

  Color picoBlue = Color.fromRGBO(55, 125, 255, 1);
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        key: _scaffoldKey,
        appBar: AppBar(
          title: const Text('Leopard Demo'),
          backgroundColor: picoBlue,
        ),
        body: Container(
            color: Colors.white,
            child: Column(
              children: [
                buildLeopardTextArea(context),
                buildLeopardWordArea(context),
                buildErrorMessage(context),
                buildLeopardStatusArea(context),
                buildStartButton(context),
                footer
              ],
            )),
      ),
    );
  }

  buildStartButton(BuildContext context) {
    final ButtonStyle buttonStyle = ElevatedButton.styleFrom(
        backgroundColor: picoBlue,
        shape: BeveledRectangleBorder(),
        textStyle: TextStyle(color: Colors.white));

    return Expanded(
      flex: 1,
      child: Container(
          child: SizedBox(
              width: 130,
              height: 65,
              child: ElevatedButton(
                style: buttonStyle,
                onPressed: (isButtonDisabled || isError)
                    ? null
                    : isRecording
                        ? _stopRecording
                        : _startRecording,
                child: Text(isRecording ? "Stop" : "Start",
                    style: TextStyle(fontSize: 30)),
              ))),
    );
  }

  buildLeopardTextArea(BuildContext context) {
    return Expanded(
        flex: 6,
        child: Container(
            alignment: Alignment.topCenter,
            color: Color(0xff25187e),
            margin: EdgeInsets.all(10),
            child: SingleChildScrollView(
                scrollDirection: Axis.vertical,
                padding: EdgeInsets.all(10),
                physics: RangeMaintainingScrollPhysics(),
                child: Align(
                    alignment: Alignment.topLeft,
                    child: Text(
                      transcriptText,
                      textAlign: TextAlign.left,
                      style: TextStyle(color: Colors.white, fontSize: 20),
                    )))));
  }

  buildLeopardWordArea(BuildContext context) {
    List<TableRow> tableRows = words.map<TableRow>((leopardWord) {
      return TableRow(children: [
        Column(children: [
          Text(leopardWord.word, style: TextStyle(color: Colors.white))
        ]),
        Column(children: [
          Text('${leopardWord.startSec.toStringAsFixed(2)}s',
              style: TextStyle(color: Colors.white))
        ]),
        Column(children: [
          Text('${leopardWord.endSec.toStringAsFixed(2)}s',
              style: TextStyle(color: Colors.white))
        ]),
        Column(children: [
          Text('${(leopardWord.confidence * 100).toStringAsFixed(0)}%',
              style: TextStyle(color: Colors.white))
        ]),
        Column(children: [
          Text('${leopardWord.speakerTag}',
              style: TextStyle(color: Colors.white))
        ]),
      ]);
    }).toList();

    return Expanded(
        flex: 4,
        child: Container(
          color: Color(0xff25187e),
          alignment: Alignment.topCenter,
          margin: EdgeInsets.all(10),
          child: Column(children: [
            Container(
                color: Colors.white,
                padding: EdgeInsets.only(bottom: 5, top: 5),
                child: Table(children: [
                  TableRow(children: [
                    Column(children: [Text("Word")]),
                    Column(children: [Text("Start")]),
                    Column(children: [Text("End")]),
                    Column(children: [Text("Confidence")]),
                    Column(children: [Text("Tag")]),
                  ])
                ])),
            Flexible(
                child: SingleChildScrollView(
                    scrollDirection: Axis.vertical,
                    padding: EdgeInsets.all(10),
                    physics: RangeMaintainingScrollPhysics(),
                    child: Table(children: tableRows)))
          ]),
        ));
  }

  buildLeopardStatusArea(BuildContext context) {
    return Expanded(
        flex: 1,
        child: Container(
            alignment: Alignment.center,
            padding: EdgeInsets.only(bottom: 20),
            child: Text(
              statusAreaText,
              style: TextStyle(color: Colors.black),
            )));
  }

  buildErrorMessage(BuildContext context) {
    return Expanded(
        flex: isError ? 4 : 0,
        child: Container(
            alignment: Alignment.center,
            margin: EdgeInsets.only(left: 20, right: 20),
            padding: EdgeInsets.all(5),
            decoration: !isError
                ? null
                : BoxDecoration(
                    color: Colors.red, borderRadius: BorderRadius.circular(5)),
            child: !isError
                ? null
                : Text(
                    errorMessage,
                    style: TextStyle(color: Colors.white, fontSize: 18),
                  )));
  }

  Widget footer = Expanded(
      flex: 1,
      child: Container(
          alignment: Alignment.bottomCenter,
          padding: EdgeInsets.only(bottom: 20),
          margin: EdgeInsets.only(top: 10),
          child: const Text(
            "Made in Vancouver, Canada by Picovoice",
            style: TextStyle(color: Color(0xff666666)),
          )));
}