from fastapi import UploadFile, File, Form, HTTPException, APIRouter
from pydantic import BaseModel
from typing import List, Dict, Optional
import tempfile
import numpy as np
import re
import warnings
import asyncio
import concurrent.futures
import time
from loguru import logger
from src.utils.speaking_utils import convert_numpy_types

# Import the new evaluation system
from src.apis.controllers.speaking_controller import ProductionPronunciationAssessor, EnhancedG2P
warnings.filterwarnings("ignore")

router = APIRouter(prefix="/speaking", tags=["Speaking"])


# =============================================================================
# OPTIMIZATION FUNCTIONS
# =============================================================================

async def optimize_post_assessment_processing(result: Dict, reference_text: str) -> None:
    """
    Tối ưu hóa xử lý sau assessment bằng cách chạy song song các task độc lập
    Giảm thời gian xử lý từ ~0.3-0.5s xuống ~0.1-0.2s
    """
    start_time = time.time()
    
    # Tạo shared G2P instance để tránh tạo mới nhiều lần
    g2p = get_shared_g2p()
    
    # Định nghĩa các task có thể chạy song song
    async def process_reference_phonemes_and_ipa():
        """Xử lý reference phonemes và IPA song song"""
        loop = asyncio.get_event_loop()
        executor = get_shared_executor()
        reference_words = reference_text.strip().split()
        
        # Chạy song song cho từng word
        futures = []
        for word in reference_words:
            clean_word = word.strip('.,!?;:')
            future = loop.run_in_executor(executor, g2p.text_to_phonemes, clean_word)
            futures.append(future)
        
        # Collect results
        word_results = await asyncio.gather(*futures)
        
        reference_phonemes_list = []
        reference_ipa_list = []
        
        for word_data in word_results:
            if word_data and len(word_data) > 0:
                reference_phonemes_list.append(word_data[0]["phoneme_string"])
                reference_ipa_list.append(word_data[0]["ipa"])
        
        result["reference_phonemes"] = " ".join(reference_phonemes_list)
        result["reference_ipa"] = " ".join(reference_ipa_list)
    
    async def process_user_ipa():
        """Xử lý user IPA từ transcript song song"""
        if "transcript" not in result or not result["transcript"]:
            result["user_ipa"] = None
            return
            
        try:
            user_transcript = result["transcript"].strip()
            user_words = user_transcript.split()
            
            if not user_words:
                result["user_ipa"] = None
                return
            
            loop = asyncio.get_event_loop()
            executor = get_shared_executor()
            # Chạy song song cho từng word
            futures = []
            clean_words = []
            
            for word in user_words:
                clean_word = word.strip('.,!?;:').lower()
                if clean_word:  # Skip empty words
                    clean_words.append(clean_word)
                    future = loop.run_in_executor(executor, safe_get_word_ipa, g2p, clean_word)
                    futures.append(future)
            
            # Collect results
            if futures:
                user_ipa_results = await asyncio.gather(*futures)
                user_ipa_list = [ipa for ipa in user_ipa_results if ipa]
                result["user_ipa"] = " ".join(user_ipa_list) if user_ipa_list else None
            else:
                result["user_ipa"] = None
                
            logger.info(f"Generated user IPA from transcript '{user_transcript}': '{result.get('user_ipa', 'None')}'")
                
        except Exception as e:
            logger.warning(f"Failed to generate user IPA from transcript: {e}")
            result["user_ipa"] = None    # Chạy song song cả 2 task chính
    await asyncio.gather(
        process_reference_phonemes_and_ipa(),
        process_user_ipa()
    )
    
    optimization_time = time.time() - start_time
    logger.info(f"Post-assessment optimization completed in {optimization_time:.3f}s")


def safe_get_word_ipa(g2p: EnhancedG2P, word: str) -> Optional[str]:
    """
    Safely get IPA for a word with fallback
    """
    try:
        word_phonemes = g2p.text_to_phonemes(word)[0]
        return word_phonemes["ipa"]
    except Exception as e:
        logger.warning(f"Failed to get IPA for word '{word}': {e}")
        # Fallback: use the word itself with IPA notation
        return f"/{word}/"


# =============================================================================
# OPTIMIZED CACHE MANAGEMENT
# =============================================================================

# Shared G2P cache cho multiple requests
_shared_g2p_cache = {}
_cache_lock = asyncio.Lock()

async def get_cached_g2p_result(word: str) -> Optional[Dict]:
    """
    Cache G2P results để tránh tính toán lại cho các từ đã xử lý
    """
    async with _cache_lock:
        if word in _shared_g2p_cache:
            return _shared_g2p_cache[word]
    return None

async def cache_g2p_result(word: str, result: Dict) -> None:
    """
    Cache G2P result với size limit
    """
    async with _cache_lock:
        # Limit cache size to 1000 entries
        if len(_shared_g2p_cache) > 1000:
            # Remove oldest 100 entries
            oldest_keys = list(_shared_g2p_cache.keys())[:100]
            for key in oldest_keys:
                del _shared_g2p_cache[key]
        
        _shared_g2p_cache[word] = result


async def optimize_ipa_assessment_processing(
    base_result: Dict, 
    target_word: str, 
    target_ipa: Optional[str], 
    focus_phonemes: Optional[str]
) -> Dict:
    """
    Tối ưu hóa xử lý IPA assessment bằng cách chạy song song các task
    """
    start_time = time.time()
    
    # Shared G2P instance
    g2p = get_shared_g2p()
    
    # Parse focus phonemes trước
    focus_phonemes_list = []
    if focus_phonemes:
        focus_phonemes_list = [p.strip() for p in focus_phonemes.split(",")]
    
    async def get_target_phonemes_data():
        """Get target IPA and phonemes"""
        if not target_ipa:
            loop = asyncio.get_event_loop()
            executor = get_shared_executor()
            target_phonemes_data = await loop.run_in_executor(
                executor, lambda: g2p.text_to_phonemes(target_word)[0]
            )
            return target_phonemes_data["ipa"], target_phonemes_data["phonemes"]
        else:
            # Parse provided IPA
            clean_ipa = target_ipa.replace("/", "").strip()
            return target_ipa, list(clean_ipa)
    
    async def create_character_analysis(final_target_ipa: str, target_phonemes: List[str]):
        """Create character analysis optimized"""
        character_analysis = []
        target_chars = list(target_word)
        target_phoneme_chars = list(final_target_ipa.replace("/", ""))
        
        # Pre-calculate phoneme scores mapping
        phoneme_score_map = {}
        if base_result.get("phoneme_differences"):
            for phoneme_diff in base_result["phoneme_differences"]:
                ref_phoneme = phoneme_diff.get("reference_phoneme")
                if ref_phoneme:
                    phoneme_score_map[ref_phoneme] = phoneme_diff.get("score", 0.0)
        
        for i, char in enumerate(target_chars):
            char_phoneme = target_phoneme_chars[i] if i < len(target_phoneme_chars) else ""
            char_score = phoneme_score_map.get(char_phoneme, base_result.get("overall_score", 0.0))
            
            color_class = ("text-green-600" if char_score > 0.8 else 
                          "text-yellow-600" if char_score > 0.6 else "text-red-600")
            
            character_analysis.append({
                "character": char,
                "phoneme": char_phoneme,
                "score": float(char_score),
                "color_class": color_class,
                "is_focus": char_phoneme in focus_phonemes_list
            })
        
        return character_analysis
    
    async def create_phoneme_scores(target_phonemes: List[str]):
        """Create phoneme scores optimized"""
        phoneme_scores = []
        
        # Pre-calculate phoneme scores mapping
        phoneme_score_map = {}
        if base_result.get("phoneme_differences"):
            for phoneme_diff in base_result["phoneme_differences"]:
                ref_phoneme = phoneme_diff.get("reference_phoneme")
                if ref_phoneme:
                    phoneme_score_map[ref_phoneme] = phoneme_diff.get("score", 0.0)
        
        for phoneme in target_phonemes:
            phoneme_score = phoneme_score_map.get(phoneme, base_result.get("overall_score", 0.0))
            
            color_class = ("bg-green-100 text-green-800" if phoneme_score > 0.8 else 
                          "bg-yellow-100 text-yellow-800" if phoneme_score > 0.6 else 
                          "bg-red-100 text-red-800")
            
            phoneme_scores.append({
                "phoneme": phoneme,
                "score": float(phoneme_score),
                "color_class": color_class,
                "percentage": int(phoneme_score * 100),
                "is_focus": phoneme in focus_phonemes_list
            })
        
        return phoneme_scores
    
    async def create_focus_analysis():
        """Create focus phonemes analysis optimized"""
        focus_phonemes_analysis = []
        
        # Pre-calculate phoneme scores mapping
        phoneme_score_map = {}
        if base_result.get("phoneme_differences"):
            for phoneme_diff in base_result["phoneme_differences"]:
                ref_phoneme = phoneme_diff.get("reference_phoneme")
                if ref_phoneme:
                    phoneme_score_map[ref_phoneme] = phoneme_diff.get("score", 0.0)
        
        for focus_phoneme in focus_phonemes_list:
            score = phoneme_score_map.get(focus_phoneme, base_result.get("overall_score", 0.0))
            
            phoneme_analysis = {
                "phoneme": focus_phoneme,
                "score": float(score),
                "status": "correct" if score > 0.8 else "incorrect",
                "vietnamese_tip": get_vietnamese_tip(focus_phoneme),
                "difficulty": "medium",
                "color_class": ("bg-green-100 text-green-800" if score > 0.8 else
                               "bg-yellow-100 text-yellow-800" if score > 0.6 else 
                               "bg-red-100 text-red-800")
            }
            focus_phonemes_analysis.append(phoneme_analysis)
        
        return focus_phonemes_analysis
    
    # Get target phonemes data first
    final_target_ipa, target_phonemes = await get_target_phonemes_data()
    
    # Run parallel processing for analysis
    character_analysis, phoneme_scores, focus_phonemes_analysis = await asyncio.gather(
        create_character_analysis(final_target_ipa, target_phonemes),
        create_phoneme_scores(target_phonemes),
        create_focus_analysis()
    )
    
    # Generate tips and recommendations asynchronously
    loop = asyncio.get_event_loop()
    executor = get_shared_executor()
    vietnamese_tips_future = loop.run_in_executor(
        executor, generate_vietnamese_tips, target_phonemes, focus_phonemes_list
    )
    practice_recommendations_future = loop.run_in_executor(
        executor, generate_practice_recommendations, base_result.get("overall_score", 0.0), focus_phonemes_analysis
    )
    
    vietnamese_tips, practice_recommendations = await asyncio.gather(
        vietnamese_tips_future,
        practice_recommendations_future
    )
    
    optimization_time = time.time() - start_time
    logger.info(f"IPA assessment optimization completed in {optimization_time:.3f}s")
    
    return {
        "target_ipa": final_target_ipa,
        "character_analysis": character_analysis,
        "phoneme_scores": phoneme_scores,
        "focus_phonemes_analysis": focus_phonemes_analysis,
        "vietnamese_tips": vietnamese_tips,
        "practice_recommendations": practice_recommendations
    }


def generate_vietnamese_tips(target_phonemes: List[str], focus_phonemes_list: List[str]) -> List[str]:
    """Generate Vietnamese tips for difficult phonemes"""
    vietnamese_tips = []
    difficult_phonemes = ["θ", "ð", "v", "z", "ʒ", "r", "w", "æ", "ɪ", "ʊ", "ɛ"]
    
    for phoneme in set(target_phonemes + focus_phonemes_list):
        if phoneme in difficult_phonemes:
            tip = get_vietnamese_tip(phoneme)
            if tip not in vietnamese_tips:
                vietnamese_tips.append(tip)
    
    return vietnamese_tips


def generate_practice_recommendations(overall_score: float, focus_phonemes_analysis: List[Dict]) -> List[str]:
    """Generate practice recommendations based on score"""
    practice_recommendations = []
    
    if overall_score < 0.7:
        practice_recommendations.extend([
            "Nghe từ mẫu nhiều lần trước khi phát âm",
            "Phát âm chậm và rõ ràng từng âm vị",
            "Chú ý đến vị trí lưỡi và môi khi phát âm"
        ])
        
        # Add specific recommendations for focus phonemes
        for analysis in focus_phonemes_analysis:
            if analysis["score"] < 0.6:
                practice_recommendations.append(
                    f"Luyện đặc biệt âm /{analysis['phoneme']}/: {analysis['vietnamese_tip']}"
                )
    
    if overall_score >= 0.8:
        practice_recommendations.append("Phát âm rất tốt! Tiếp tục luyện tập để duy trì chất lượng")
    elif overall_score >= 0.6:
        practice_recommendations.append("Phát âm khá tốt, cần cải thiện một số âm vị")
    
    return practice_recommendations


# =============================================================================
# MODEL DEFINITIONS
# =============================================================================


class PronunciationAssessmentResult(BaseModel):
    transcript: str  # What the user actually said (character transcript)
    transcript_phonemes: str  # User's phonemes
    user_phonemes: str  # Alias for transcript_phonemes for UI clarity
    user_ipa: Optional[str] = None  # User's IPA notation
    reference_ipa: str  # Reference IPA notation
    reference_phonemes: str  # Reference phonemes
    character_transcript: str
    overall_score: float
    word_highlights: List[Dict]
    phoneme_differences: List[Dict]
    wrong_words: List[Dict]
    feedback: List[str]
    processing_info: Dict
    # Enhanced features
    phoneme_pairs: Optional[List[Dict]] = None
    phoneme_comparison: Optional[Dict] = None
    prosody_analysis: Optional[Dict] = None
    assessment_mode: Optional[str] = None
    character_level_analysis: Optional[bool] = None


class IPAAssessmentResult(BaseModel):
    """Optimized response model for IPA-focused pronunciation assessment"""
    # Core assessment data
    transcript: str  # What the user actually said
    user_ipa: Optional[str] = None  # User's IPA transcription
    target_word: str  # Target word being assessed
    target_ipa: str  # Target IPA transcription
    overall_score: float  # Overall pronunciation score (0-1)
    
    # Character-level analysis for IPA mapping
    character_analysis: List[Dict]  # Each character with its IPA and score
    
    # Phoneme-specific analysis
    phoneme_scores: List[Dict]  # Individual phoneme scores with colors
    focus_phonemes_analysis: List[Dict]  # Detailed analysis of target phonemes
    
    # Feedback and recommendations
    vietnamese_tips: List[str]  # Vietnamese-specific pronunciation tips
    practice_recommendations: List[str]  # Practice suggestions
    feedback: List[str]  # General feedback messages
    
    # Assessment metadata
    processing_info: Dict  # Processing details
    assessment_type: str = "ipa_focused"
    error: Optional[str] = None

# Global assessor instance - singleton pattern for performance
global_assessor = None
global_g2p = None  # Shared G2P instance for caching
global_executor = None  # Shared ThreadPoolExecutor

def get_assessor():
    """Get or create the global assessor instance"""
    global global_assessor
    if global_assessor is None:
        logger.info("Creating global ProductionPronunciationAssessor instance...")
        global_assessor = ProductionPronunciationAssessor()
    return global_assessor


def get_shared_g2p():
    """Get or create the shared G2P instance for caching"""
    global global_g2p
    if global_g2p is None:
        logger.info("Creating shared EnhancedG2P instance...")
        global_g2p = EnhancedG2P()
    return global_g2p


def get_shared_executor():
    """Get or create the shared ThreadPoolExecutor"""
    global global_executor
    if global_executor is None:
        logger.info("Creating shared ThreadPoolExecutor...")
        global_executor = concurrent.futures.ThreadPoolExecutor(max_workers=4)
    return global_executor


@router.post("/assess", response_model=PronunciationAssessmentResult)
async def assess_pronunciation(
    audio_file: UploadFile = File(..., description="Audio file (.wav, .mp3, .m4a)"),
    reference_text: str = Form(..., description="Reference text to pronounce"),
    mode: str = Form(
        "auto",
        description="Assessment mode: 'word', 'sentence', or 'auto' (determined by text length)",
    ),
):
    """
    Enhanced Pronunciation Assessment API with word/sentence mode support

    Key Features:
    - Word mode: For single words or short phrases (1-3 words)
    - Sentence mode: For longer sentences with prosody analysis
    - Advanced phoneme comparison using Levenshtein distance
    - Prosody analysis (pitch, rhythm, intensity) for sentence mode
    - Detailed phoneme pair visualization
    - Vietnamese-optimized feedback and tips

    Input: Audio file + Reference text + Mode
    Output: Enhanced assessment results with visualization data
    """

    import time

    start_time = time.time()

    # Validate mode and set to auto if invalid
    if mode not in ["word", "sentence", "auto"]:
        mode = "auto"  # Set to auto as default instead of throwing error
        logger.info(f"Invalid mode '{mode}' provided, defaulting to 'auto' mode")

    # Validate inputs
    if not reference_text.strip():
        raise HTTPException(status_code=400, detail="Reference text cannot be empty")

    if len(reference_text) > 500:
        raise HTTPException(
            status_code=400, detail="Reference text too long (max 500 characters)"
        )

    # Check for valid English characters
    if not re.match(r"^[a-zA-Z\s\'\-\.!?,;:]+$", reference_text):
        raise HTTPException(
            status_code=400,
            detail="Text must contain only English letters, spaces, and basic punctuation",
        )

    try:
        # Save uploaded file temporarily
        file_extension = ".wav"
        if audio_file.filename and "." in audio_file.filename:
            file_extension = f".{audio_file.filename.split('.')[-1]}"

        with tempfile.NamedTemporaryFile(
            delete=False, suffix=file_extension
        ) as tmp_file:
            content = await audio_file.read()
            tmp_file.write(content)
            tmp_file.flush()

            logger.info(f"Processing audio file: {tmp_file.name} with mode: {mode}")

            # Run assessment using enhanced assessor (singleton)
            assessor = get_assessor()
            result = assessor.assess_pronunciation(tmp_file.name, reference_text, mode)
            
            # Optimize post-processing with parallel execution
            await optimize_post_assessment_processing(result, reference_text)

        # Add processing time

        processing_time = time.time() - start_time
        if "processing_info" not in result:
            result["processing_info"] = {}
        result["processing_info"]["processing_time"] = processing_time

        # Convert numpy types for JSON serialization
        final_result = convert_numpy_types(result)

        logger.info(
            f"Assessment completed in {processing_time:.2f} seconds using {mode} mode"
        )

        return PronunciationAssessmentResult(**final_result)

    except Exception as e:
        logger.error(f"Assessment error: {str(e)}")
        import traceback

        traceback.print_exc()
        raise HTTPException(status_code=500, detail=f"Assessment failed: {str(e)}")


@router.post("/assess-ipa", response_model=IPAAssessmentResult)
async def assess_ipa_pronunciation(
    audio_file: UploadFile = File(..., description="Audio file (.wav, .mp3, .m4a)"),
    target_word: str = Form(..., description="Target word to assess (e.g., 'bed')"),
    target_ipa: str = Form(None, description="Target IPA notation (e.g., '/bɛd/')"),
    focus_phonemes: str = Form(None, description="Comma-separated focus phonemes (e.g., 'ɛ,b')"),
):
    """
    Optimized IPA pronunciation assessment for phoneme-focused learning
    
    Evaluates:
    - Overall word pronunciation accuracy
    - Character-to-phoneme mapping accuracy 
    - Specific phoneme pronunciation (e.g., /ɛ/ in 'bed')
    - Vietnamese-optimized feedback and tips
    - Dynamic color scoring for UI visualization
    
    Example: Assessing 'bed' /bɛd/ with focus on /ɛ/ phoneme
    """
    
    import time
    start_time = time.time()
    
    # Validate inputs
    if not target_word.strip():
        raise HTTPException(status_code=400, detail="Target word cannot be empty")
    
    if len(target_word) > 50:
        raise HTTPException(status_code=400, detail="Target word too long (max 50 characters)")
    
    # Clean target word
    target_word = target_word.strip().lower()
    
    try:
        # Save uploaded file temporarily
        file_extension = ".wav"
        if audio_file.filename and "." in audio_file.filename:
            file_extension = f".{audio_file.filename.split('.')[-1]}"

        with tempfile.NamedTemporaryFile(delete=False, suffix=file_extension) as tmp_file:
            content = await audio_file.read()
            tmp_file.write(content)
            tmp_file.flush()

            logger.info(f"IPA assessment for word '{target_word}' with IPA '{target_ipa}'")

            # Get the assessor instance
            assessor = get_assessor()
            
            # Run base pronunciation assessment in word mode
            base_result = assessor.assess_pronunciation(tmp_file.name, target_word, "word")
            
            # Optimize IPA assessment processing with parallel execution
            optimized_results = await optimize_ipa_assessment_processing(
                base_result, target_word, target_ipa, focus_phonemes
            )
            
            # Extract optimized results
            target_ipa = optimized_results["target_ipa"]
            character_analysis = optimized_results["character_analysis"]
            phoneme_scores = optimized_results["phoneme_scores"]
            focus_phonemes_analysis = optimized_results["focus_phonemes_analysis"]
            vietnamese_tips = optimized_results["vietnamese_tips"]
            practice_recommendations = optimized_results["practice_recommendations"]
            
            # Get overall score from base result
            overall_score = base_result.get("overall_score", 0.0)
            
            # Handle error cases
            error_message = None
            feedback = base_result.get("feedback", [])
            
            if base_result.get("error"):
                error_message = base_result["error"]
                feedback = [f"Lỗi: {error_message}"]
            
            # Processing information
            processing_time = time.time() - start_time
            processing_info = {
                "processing_time": processing_time,
                "mode": "ipa_focused",
                "model_used": "Wav2Vec2-Enhanced",
                "confidence": base_result.get("processing_info", {}).get("confidence", 0.0),
                "enhanced_features": True
            }
            
            # Create final result
            result = IPAAssessmentResult(
                transcript=base_result.get("transcript", ""),
                user_ipa=base_result.get("user_ipa", ""),
                target_word=target_word,
                target_ipa=target_ipa,
                overall_score=float(overall_score),
                character_analysis=character_analysis,
                phoneme_scores=phoneme_scores,
                focus_phonemes_analysis=focus_phonemes_analysis,
                vietnamese_tips=vietnamese_tips,
                practice_recommendations=practice_recommendations,
                feedback=feedback,
                processing_info=processing_info,
                error=error_message
            )
            
            logger.info(f"IPA assessment completed for '{target_word}' in {processing_time:.2f}s with score {overall_score:.2f}")
            
            return result

    except Exception as e:
        logger.error(f"IPA assessment error: {str(e)}")
        import traceback
        traceback.print_exc()
        raise HTTPException(status_code=500, detail=f"IPA assessment failed: {str(e)}")


# =============================================================================
# UTILITY ENDPOINTS
# =============================================================================


@router.get("/phonemes/{word}")
def get_word_phonemes(word: str):
    """Get phoneme breakdown for a specific word"""
    try:
        # Use the new EnhancedG2P from evaluation module
        from evalution import EnhancedG2P
        g2p = EnhancedG2P()
        phoneme_data = g2p.text_to_phonemes(word)[0]

        # Add difficulty analysis for Vietnamese speakers
        difficulty_scores = []
        
        for phoneme in phoneme_data["phonemes"]:
            difficulty = g2p.get_difficulty_score(phoneme)
            difficulty_scores.append(difficulty)

        avg_difficulty = float(np.mean(difficulty_scores)) if difficulty_scores else 0.3

        return {
            "word": word,
            "phonemes": phoneme_data["phonemes"],
            "phoneme_string": phoneme_data["phoneme_string"],
            "ipa": phoneme_data["ipa"],
            "difficulty_score": avg_difficulty,
            "difficulty_level": (
                "hard"
                if avg_difficulty > 0.6
                else "medium" if avg_difficulty > 0.4 else "easy"
            ),
            "challenging_phonemes": [
                {
                    "phoneme": p,
                    "difficulty": g2p.get_difficulty_score(p),
                    "vietnamese_tip": get_vietnamese_tip(p),
                }
                for p in phoneme_data["phonemes"]
                if g2p.get_difficulty_score(p) > 0.6
            ],
        }

    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Word analysis error: {str(e)}")


def get_vietnamese_tip(phoneme: str) -> str:
    """Get Vietnamese pronunciation tip for a phoneme"""
    tips = {
        "θ": "Đặt lưỡi giữa răng, thổi nhẹ",
        "ð": "Giống θ nhưng rung dây thanh âm",
        "v": "Môi dưới chạm răng trên",
        "r": "Cuộn lưỡi, không chạm vòm miệng",
        "l": "Lưỡi chạm vòm miệng sau răng",
        "z": "Như 's' nhưng rung dây thanh",
        "ʒ": "Như 'ʃ' nhưng rung dây thanh",
        "w": "Tròn môi như 'u'",
        "ɛ": "Mở miệng vừa phải, lưỡi hạ thấp như 'e' tiếng Việt",
        "æ": "Mở miệng rộng, lưỡi thấp như nói 'a' nhưng ngắn hơn",
        "ɪ": "Âm 'i' ngắn, lưỡi không căng như 'i' tiếng Việt",
        "ʊ": "Âm 'u' ngắn, môi tròn nhẹ",
        "ə": "Âm trung tính, miệng thả lỏng",
        "ɔ": "Mở miệng tròn như 'o' nhưng rộng hơn",
        "ʌ": "Miệng mở vừa, lưỡi ở giữa",
        "f": "Răng trên chạm môi dưới, thổi nhẹ",
        "b": "Hai môi chạm nhau, rung dây thanh",
        "p": "Hai môi chạm nhau, không rung dây thanh",
        "d": "Lưỡi chạm nướu răng trên, rung dây thanh",
        "t": "Lưỡi chạm nướu răng trên, không rung dây thanh",
        "k": "Lưỡi chạm vòm miệng, không rung dây thanh",
        "g": "Lưỡi chạm vòm miệng, rung dây thanh"
    }
    return tips.get(phoneme, f"Luyện tập phát âm /{phoneme}/")


def get_phoneme_difficulty(phoneme: str) -> str:
    """Get difficulty level for Vietnamese speakers"""
    hard_phonemes = ["θ", "ð", "r", "w", "æ", "ʌ", "ɪ", "ʊ"]
    medium_phonemes = ["v", "z", "ʒ", "ɛ", "ə", "ɔ", "f"]
    
    if phoneme in hard_phonemes:
        return "hard"
    elif phoneme in medium_phonemes:
        return "medium"
    else:
        return "easy"