IMPLEMENTATION.md

# Implementation Guide

This guide explains how to integrate the Quranic Recitation Dataset into your application using the **Cloudflare Edge CDN** and **Protocol Buffer** timing data.

## 🏗️ Architecture

```
┌─────────────┐     ┌──────────────────────────┐     ┌─────────────────┐
│  Your App   │────▶│  Cloudflare Worker CDN   │────▶│   HuggingFace   │
│  (Web/Mobile)│     │  recitation-cdn.         │     │   Dataset Repo  │
│             │◀────│  mughalistian.workers.dev │◀────│                 │
└─────────────┘     └──────────────────────────┘     └─────────────────┘
                    • Edge caching (1 year)
                    • Range requests (206)
                    • CORS enabled
                    • Slug → folder mapping
```

### Per-Surah Model
Each surah is stored as a **single audio file** (not per-ayah). To play a specific ayah:
1. Load the surah `.opus` file
2. Parse the `.pb` timing data
3. Seek the audio player to the ayah's first word `timestamp_from`

This dramatically reduces the number of HTTP requests (from ~6,236 per reciter down to 114) while maintaining word-level precision.

---

## 🗂️ Data Structure

### CDN URL Format
```
https://cdn.mualim.app/{slug}/{surah_number}.{opus|pb}
```

Where:
- `{slug}` — URL-friendly reciter identifier (see slug map in README.md)
- `{surah_number}` — 3-digit zero-padded surah number (e.g., `001`, `114`)

### Example URLs
```bash
# Audio: Mishari Rashid Al-Afasy, Surah Al-Baqarah
https://cdn.mualim.app/mishari-rashid-al-afasy-murattal-hafs/002.opus

# Timing: Same reciter, same surah
https://cdn.mualim.app/mishari-rashid-al-afasy-murattal-hafs/002.pb
```

### Direct HuggingFace Fallback
If the CDN is unreachable, fall back to the raw HuggingFace URL:
```
https://huggingface.co/datasets/zaibihassan/Quranic-Recitation-Data/resolve/main/{Folder Name}/{Surah}/{File}
```

> **Note:** The folder names contain spaces and special characters. The CDN handles slug-to-folder mapping automatically.

---

## ⏱️ Protocol Buffer Schema

The `.pb` timing files use this schema:

```protobuf
syntax = "proto3";
package recitation;

message WordSegment {
  int32 word_index_0_based = 1;
  int32 word_index_1_based = 2;
  int32 timestamp_from = 3;      // ms from start of surah audio
  int32 timestamp_to = 4;        // ms from start of surah audio
}

message VerseSegments {
  repeated WordSegment segments = 1;
}

message SurahTimestamps {
  map<string, VerseSegments> verses = 1;  // key = "surah:ayah" e.g. "1:1"
}
```

### Key Concept
Timestamps are **relative to the start of the surah audio**. To play ayah 5 of surah 2:
```
seekPosition = verses["2:5"].segments[0].timestamp_from  // in milliseconds
```

---

## 💻 Tech Stack Implementations

The core pattern across all frameworks:
1. Fetch the `.pb` timing data for the surah
2. Decode it using a protobuf library
3. Load the `.opus` audio file
4. Listen to playback position (in milliseconds)
5. Find the word where `timestamp_from <= currentTimeMs <= timestamp_to`
6. Apply a highlighted style to that word

### 1. JavaScript / TypeScript (Web)

```javascript
import protobuf from 'protobufjs';

const CDN_BASE = 'https://cdn.mualim.app';

async function loadSurahData(slug, surahNum) {
  const padded = String(surahNum).padStart(3, '0');
  
  // Fetch protobuf timing data
  const pbResponse = await fetch(`${CDN_BASE}/${slug}/${padded}.pb`);
  const pbBuffer = await pbResponse.arrayBuffer();
  
  // Decode using your compiled protobuf schema
  const root = await protobuf.load('recitation.proto');
  const SurahTimestamps = root.lookupType('recitation.SurahTimestamps');
  const timingData = SurahTimestamps.decode(new Uint8Array(pbBuffer));
  
  return timingData;
}

// Audio playback with word highlighting
const audio = new Audio(`${CDN_BASE}/mishari-rashid-al-afasy-murattal-hafs/001.opus`);
const timings = await loadSurahData('mishari-rashid-al-afasy-murattal-hafs', 1);

let activeWordIndex = -1;

audio.addEventListener('timeupdate', () => {
  const currentTimeMs = audio.currentTime * 1000;
  const verseTimings = timings.verses['1:1']; // Current verse
  
  if (!verseTimings) return;
  
  const match = verseTimings.segments.find(
    seg => currentTimeMs >= seg.timestampFrom && currentTimeMs <= seg.timestampTo
  );
  
  if (match && match.wordIndex0Based !== activeWordIndex) {
    activeWordIndex = match.wordIndex0Based;
    highlightWord(activeWordIndex); // Your UI function
  }
});

// Seek to a specific ayah
function seekToAyah(surah, ayah) {
  const key = `${surah}:${ayah}`;
  const verse = timings.verses[key];
  if (verse && verse.segments.length > 0) {
    audio.currentTime = verse.segments[0].timestampFrom / 1000;
    audio.play();
  }
}

audio.play();
```

### 2. React.js

```tsx
import React, { useState, useEffect, useRef } from 'react';

const CDN_BASE = 'https://cdn.mualim.app';

const QuranPlayer = ({ slug, surahNum, words, verseKey }) => {
  const audioRef = useRef<HTMLAudioElement>(null);
  const [activeWordIndex, setActiveWordIndex] = useState(-1);
  const [timings, setTimings] = useState(null);

  const padded = String(surahNum).padStart(3, '0');

  useEffect(() => {
    // Load protobuf timing data on mount
    fetch(`${CDN_BASE}/${slug}/${padded}.pb`)
      .then(res => res.arrayBuffer())
      .then(buf => {
        // Decode protobuf (using your compiled schema)
        const decoded = SurahTimestamps.decode(new Uint8Array(buf));
        setTimings(decoded);
      });
  }, [slug, surahNum]);

  const handleTimeUpdate = () => {
    if (!audioRef.current || !timings) return;
    const currentTimeMs = audioRef.current.currentTime * 1000;
    const verse = timings.verses[verseKey];
    if (!verse) return;

    const match = verse.segments.find(
      s => currentTimeMs >= s.timestampFrom && currentTimeMs <= s.timestampTo
    );

    setActiveWordIndex(match ? match.wordIndex0Based : -1);
  };

  return (
    <div>
      <audio
        ref={audioRef}
        src={`${CDN_BASE}/${slug}/${padded}.opus`}
        onTimeUpdate={handleTimeUpdate}
        controls
      />
      <div className="quran-text" dir="rtl">
        {words.map((word, i) => (
          <span
            key={i}
            className={i === activeWordIndex ? 'text-blue-500 font-bold' : ''}
          >
            {word}{' '}
          </span>
        ))}
      </div>
    </div>
  );
};
```

### 3. Flutter (Dart)

Using `just_audio` and the `protobuf` package:

```dart
import 'package:flutter/material.dart';
import 'package:just_audio/just_audio.dart';
import 'package:http/http.dart' as http;
import 'recitation.pb.dart'; // Generated from recitation.proto

const cdnBase = 'https://cdn.mualim.app';

class QuranPlayerWidget extends StatefulWidget {
  final String slug;
  final int surahNum;
  final List<String> words;
  final String verseKey; // e.g., "1:1"

  const QuranPlayerWidget({
    required this.slug,
    required this.surahNum,
    required this.words,
    required this.verseKey,
  });

  @override
  State<QuranPlayerWidget> createState() => _QuranPlayerState();
}

class _QuranPlayerState extends State<QuranPlayerWidget> {
  final AudioPlayer _player = AudioPlayer();
  SurahTimestamps? _timings;
  int _activeWordIndex = -1;

  @override
  void initState() {
    super.initState();
    _init();
  }

  Future<void> _init() async {
    final padded = widget.surahNum.toString().padLeft(3, '0');
    
    // Load protobuf timing data
    final pbUrl = '$cdnBase/${widget.slug}/$padded.pb';
    final response = await http.get(Uri.parse(pbUrl));
    _timings = SurahTimestamps.fromBuffer(response.bodyBytes);

    // Load audio (supports range requests for seeking)
    final audioUrl = '$cdnBase/${widget.slug}/$padded.opus';
    await _player.setUrl(audioUrl);

    // Track position for word highlighting
    _player.positionStream.listen((position) {
      final currentTimeMs = position.inMilliseconds;
      final verse = _timings?.verses[widget.verseKey];
      if (verse == null) return;

      int matchIndex = -1;
      for (final seg in verse.segments) {
        if (currentTimeMs >= seg.timestampFrom && 
            currentTimeMs <= seg.timestampTo) {
          matchIndex = seg.wordIndex0Based;
          break;
        }
      }

      if (_activeWordIndex != matchIndex) {
        setState(() => _activeWordIndex = matchIndex);
      }
    });
  }

  /// Seek to a specific ayah within the loaded surah
  void seekToAyah(String verseKey) {
    final verse = _timings?.verses[verseKey];
    if (verse != null && verse.segments.isNotEmpty) {
      final seekMs = verse.segments.first.timestampFrom;
      _player.seek(Duration(milliseconds: seekMs));
      _player.play();
    }
  }

  @override
  void dispose() {
    _player.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Wrap(
      textDirection: TextDirection.rtl,
      children: widget.words.asMap().entries.map((entry) {
        final isActive = entry.key == _activeWordIndex;
        return Text(
          '${entry.value} ',
          style: TextStyle(
            color: isActive ? Colors.blue : Colors.black,
            fontWeight: isActive ? FontWeight.bold : FontWeight.normal,
            fontSize: 28,
          ),
        );
      }).toList(),
    );
  }
}
```

### 4. Swift (iOS)

```swift
import AVFoundation

let cdnBase = "https://cdn.mualim.app"

class QuranPlayer {
    var player: AVPlayer?
    var timings: SurahTimestamps?  // Generated from protobuf
    var activeWordIndex: Int = -1
    
    func loadSurah(slug: String, surahNum: Int) async {
        let padded = String(format: "%03d", surahNum)
        
        // Load audio with range request support
        let audioURL = URL(string: "\(cdnBase)/\(slug)/\(padded).opus")!
        player = AVPlayer(url: audioURL)
        
        // Load protobuf timing
        let pbURL = URL(string: "\(cdnBase)/\(slug)/\(padded).pb")!
        let (data, _) = try! await URLSession.shared.data(from: pbURL)
        timings = try! SurahTimestamps(serializedBytes: data)
        
        // Observe playback position
        player?.addPeriodicTimeObserver(
            forInterval: CMTime(value: 1, timescale: 30),
            queue: .main
        ) { [weak self] time in
            self?.updateHighlight(currentTimeMs: Int(time.seconds * 1000))
        }
    }
    
    func seekToAyah(_ verseKey: String) {
        guard let verse = timings?.verses[verseKey],
              let firstSeg = verse.segments.first else { return }
        let seekTime = CMTime(value: Int64(firstSeg.timestampFrom), timescale: 1000)
        player?.seek(to: seekTime)
        player?.play()
    }
    
    private func updateHighlight(currentTimeMs: Int) {
        // Find active word in current verse's segments
        guard let verse = timings?.verses["1:1"] else { return }
        
        for seg in verse.segments {
            if currentTimeMs >= seg.timestampFrom && currentTimeMs <= seg.timestampTo {
                activeWordIndex = Int(seg.wordIndex0Based)
                return
            }
        }
    }
}
```

---

## 🤖 AI Prompt Template

Copy this prompt into ChatGPT, Claude, or Copilot to scaffold your integration:

> I am building a Quran application with **word-by-word audio highlighting** (karaoke style).
> 
> **CDN Base URL:** `https://cdn.mualim.app`
> **URL Format:** `{CDN_BASE}/{reciter-slug}/{surah_padded}.opus` (audio) and `.pb` (timing)
> 
> The timing data is a Protocol Buffer file using this schema:
> ```protobuf
> message WordSegment { int32 word_index_0_based=1; int32 word_index_1_based=2; int32 timestamp_from=3; int32 timestamp_to=4; }
> message VerseSegments { repeated WordSegment segments=1; }
> message SurahTimestamps { map<string, VerseSegments> verses=1; }
> ```
> 
> Each surah is a **single audio file**. Timestamps are in **milliseconds from the start of the surah audio**. The `.pb` file contains all verses of that surah.
> 
> To play a specific ayah, seek the audio player to `verses["surah:ayah"].segments[0].timestamp_from` ms.
> 
> Please write the complete implementation using **[YOUR FRAMEWORK]**:
> 1. Fetch and decode the `.pb` file
> 2. Stream the `.opus` audio with seeking support
> 3. Track playback position in milliseconds
> 4. Highlight the active word using `timestamp_from <= currentMs <= timestamp_to`
> 5. Support seeking to any ayah within the surah