"""
Copyright 2024-2026 ChatterMate

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

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.
"""

from typing import Tuple, List, Optional
from app.core.logger import get_logger

logger = get_logger(__name__)

# Try to import TextBlob, fall back to basic keyword analysis if unavailable
try:
    from textblob import TextBlob
    TEXTBLOB_AVAILABLE = True
except ImportError:
    TEXTBLOB_AVAILABLE = False
    logger.warning("TextBlob not installed. Using basic keyword-based sentiment analysis. "
                   "Install with: pip install textblob")


# Basic keyword lists for fallback sentiment analysis
POSITIVE_KEYWORDS = {
    'thank', 'thanks', 'great', 'awesome', 'excellent', 'good', 'love',
    'perfect', 'amazing', 'wonderful', 'helpful', 'appreciate', 'happy',
    'pleased', 'fantastic', 'brilliant', 'nice', 'best', 'super', 'cool',
    'resolved', 'fixed', 'works', 'working', 'solved'
}

NEGATIVE_KEYWORDS = {
    'bad', 'terrible', 'awful', 'horrible', 'worst', 'hate', 'angry',
    'frustrated', 'annoyed', 'disappointed', 'useless', 'broken', 'bug',
    'error', 'fail', 'failed', 'wrong', 'issue', 'problem', 'slow',
    'crash', 'crashed', 'stuck', 'ridiculous', 'unacceptable', 'poor',
    'waste', 'stupid', 'pathetic', 'sucks', 'rubbish'
}


def _analyze_with_textblob(text: str) -> Tuple[str, float]:
    """Analyze sentiment using TextBlob."""
    blob = TextBlob(text)
    polarity = blob.sentiment.polarity  # -1.0 to 1.0

    if polarity > 0.1:
        label = "positive"
    elif polarity < -0.1:
        label = "negative"
    else:
        label = "neutral"

    return label, round(polarity, 4)


def _analyze_with_keywords(text: str) -> Tuple[str, float]:
    """Fallback keyword-based sentiment analysis."""
    words = set(text.lower().split())

    positive_count = len(words & POSITIVE_KEYWORDS)
    negative_count = len(words & NEGATIVE_KEYWORDS)

    total = positive_count + negative_count
    if total == 0:
        return "neutral", 0.0

    # Simple scoring: range from -1 to 1
    score = (positive_count - negative_count) / total

    if score > 0.1:
        label = "positive"
    elif score < -0.1:
        label = "negative"
    else:
        label = "neutral"

    return label, round(score, 4)


def analyze_sentiment(text: str) -> Tuple[str, float]:
    """
    Analyze the sentiment of a text message.

    Returns:
        Tuple of (sentiment_label, sentiment_score)
        - sentiment_label: 'positive', 'neutral', or 'negative'
        - sentiment_score: float from -1.0 (most negative) to 1.0 (most positive)
    """
    if not text or not text.strip():
        return "neutral", 0.0

    try:
        if TEXTBLOB_AVAILABLE:
            return _analyze_with_textblob(text)
        else:
            return _analyze_with_keywords(text)
    except Exception as e:
        logger.error(f"Error analyzing sentiment: {str(e)}")
        return "neutral", 0.0


def compute_session_sentiment(
    sentiment_scores: List[float],
    sentiment_labels: List[str]
) -> Tuple[Optional[str], Optional[float]]:
    """
    Compute the overall sentiment for a session from individual message sentiments.

    Args:
        sentiment_scores: List of sentiment scores from customer messages
        sentiment_labels: List of sentiment labels from customer messages

    Returns:
        Tuple of (overall_label, overall_score) or (None, None) if no data
    """
    if not sentiment_scores:
        return None, None

    avg_score = sum(sentiment_scores) / len(sentiment_scores)

    if avg_score > 0.1:
        label = "positive"
    elif avg_score < -0.1:
        label = "negative"
    else:
        label = "neutral"

    return label, round(avg_score, 4)