"""
Helper utilities for the NLP Insight Engine.
"""

from collections import Counter


# ── Entity display helpers ───────────────────────────────────────────────────

ENTITY_COLORS = {
    "PER": "entity-PER",
    "ORG": "entity-ORG",
    "LOC": "entity-LOC",
    "MISC": "entity-MISC",
    "DATE": "entity-DATE",
}


def format_entities(entities: list[dict]) -> str:
    """Render entities as styled HTML tags."""
    tags = []
    for ent in entities:
        css_class = ENTITY_COLORS.get(ent["entity_group"], "entity-default")
        tags.append(
            f'<span class="entity-tag {css_class}">'
            f'{ent["word"]} '
            f'<small>({ent["entity_group"]})</small>'
            f"</span>"
        )
    return " ".join(tags)


def build_entity_summary(entities: list[dict]) -> dict:
    """Count entities by type for pie chart."""
    return dict(Counter(e["entity_group"] for e in entities))


# ── File helpers ─────────────────────────────────────────────────────────────


def extract_text_from_file(uploaded_file) -> str:
    """Extract text from uploaded .txt or .csv files."""
    name = uploaded_file.name.lower()
    try:
        if name.endswith(".txt"):
            return uploaded_file.read().decode("utf-8", errors="replace")
        elif name.endswith(".csv"):
            import pandas as pd
            df = pd.read_csv(uploaded_file)
            # Concatenate all string columns
            text_cols = df.select_dtypes(include="object")
            return " ".join(text_cols.astype(str).values.flatten())
        else:
            return ""
    except Exception as e:
        return f"Error reading file: {e}"


# ── Example texts ────────────────────────────────────────────────────────────

EXAMPLE_TEXTS = {
    "📰 Tech News Article": (
        "Artificial intelligence is transforming industries at an unprecedented pace. "
        "Companies like Google, Microsoft, and OpenAI are investing billions in developing "
        "large language models that can understand and generate human-like text. Meanwhile, "
        "the European Union has introduced the AI Act, the world's first comprehensive "
        "regulation framework for artificial intelligence. Critics argue the regulations "
        "could stifle innovation in Europe, while supporters believe they are necessary to "
        "protect citizens from potential harms. The debate continues as AI capabilities "
        "advance rapidly, with new breakthroughs in multimodal understanding, reasoning, "
        "and code generation emerging every month."
    ),
    "⭐ Product Review": (
        "I purchased this laptop three weeks ago and I'm extremely disappointed. The build "
        "quality feels cheap despite the premium price tag. The keyboard is mushy, the "
        "trackpad is unresponsive half the time, and the battery barely lasts four hours. "
        "Customer support was unhelpful — they kept transferring me between departments. "
        "The only positive is the screen quality, which is genuinely excellent. However, "
        "a good display doesn't make up for all the other issues. I would not recommend "
        "this product to anyone. Save your money and look at alternatives from Dell or "
        "Lenovo instead."
    ),
    "🏢 Business Report": (
        "The quarterly earnings report for Acme Corporation shows a 15 percent increase "
        "in revenue compared to the same period last year. The company's expansion into "
        "the Asian market, particularly Japan and South Korea, has been a major growth "
        "driver. CEO Sarah Johnson noted that the new product line launched in March "
        "exceeded expectations, generating over 50 million dollars in its first quarter. "
        "The board of directors approved an additional investment of 200 million dollars "
        "in research and development for 2025. Chief Financial Officer Michael Chen "
        "highlighted that operating margins improved by 3.2 percentage points, reaching "
        "22.8 percent. The company plans to open new offices in London and Singapore by "
        "the end of the fiscal year."
    ),
    "🌍 Climate Report": (
        "The latest report from the United Nations Environment Programme warns that global "
        "temperatures could rise by 2.8 degrees Celsius above pre-industrial levels by "
        "the end of the century without significant policy changes. Dr. Maria Rodriguez, "
        "lead author from the University of Oxford, stated that immediate action is needed "
        "across all sectors. The energy transition is accelerating in some regions, with "
        "renewable energy capacity growing by 50 percent in 2024 according to the "
        "International Energy Agency. However, fossil fuel consumption continues to rise "
        "in developing nations. The report recommends tripling investment in clean energy "
        "infrastructure and implementing carbon pricing mechanisms across all major "
        "economies by 2030."
    ),
}