import os
import logging

from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse
from fastapi import FastAPI, HTTPException
from pydantic import BaseModel, Field

from retrieval import search, EXACT_SI, EXACT_TA, normalize
from intents import detect_smalltalk, smalltalk_reply
from firestore_client import get_advice_by_id

# Optional Qwen output layer
try:
    from finetuned_llm import generate_grounded_answer
except Exception:
    generate_grounded_answer = None


app = FastAPI(title="Coco-Guide Backend", version="1.3")


# -----------------------------
# Logging
# -----------------------------
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger("coco_guide")


# -----------------------------
# CORS
# -----------------------------
DEBUG = os.getenv("DEBUG", "true").lower() == "true"

if DEBUG:
    app.add_middleware(
        CORSMiddleware,
        allow_origins=["*"],
        allow_credentials=False,
        allow_methods=["*"],
        allow_headers=["*"],
    )
else:
    app.add_middleware(
        CORSMiddleware,
        allow_origins=[
            "https://your-frontend-domain.com"
        ],
        allow_credentials=True,
        allow_methods=["*"],
        allow_headers=["*"],
    )


# -----------------------------
# Config
# -----------------------------
USE_FINE_TUNED_MODEL = os.getenv("USE_FINE_TUNED_MODEL", "false").lower() == "true"
FALLBACK_THRESHOLD = float(os.getenv("FALLBACK_THRESHOLD", "0.60"))
CLARIFY_THRESHOLD = float(os.getenv("CLARIFY_THRESHOLD", "0.72"))


# -----------------------------
# Request Schema
# -----------------------------
class ChatRequest(BaseModel):
    message: str = Field(..., min_length=1, max_length=500)
    language: str


# -----------------------------
# Messages
# -----------------------------
FALLBACK_SI = "කණගාටුයි, මට සහාය විය හැක්කේ පොල් වගාවට අදාළ කරුණු සඳහා පමණි. කරුණාකර ඔබේ ප්‍රශ්නය නැවත විමසන්න."
FALLBACK_TA = "மன்னிக்கவும், அந்தத் தகவல் தற்போது எங்களிடம் இல்லை. தயவுசெய்து மேலதிக ஆலோசனைகளுக்கு தென்னை பயிர்ச்செய்கை அதிகாரியைத் தொடர்பு கொள்ளவும்."

CLARIFY_SI = "කරුණාකර ඔබගේ ප්‍රශ්නය තව විස්තර කරන්න."
CLARIFY_TA = "தயவுசெய்து உங்கள் கேள்வியை மேலும் விளக்கவும்."

LOCATION_FALLBACK_SI = "කණගාටුයි, මෙම පද්ධතිය කුරුණෑගල දිස්ත්‍රික්කයේ පොල් වගාවට අදාළ උපදෙස් සඳහා පමණක් සීමා වී ඇත."
LOCATION_FALLBACK_TA = "மன்னிக்கவும், இந்த அமைப்பு குருநாகல் மாவட்டத்திலுள்ள தென்னைப் பயிர்ச்செய்கை தொடர்பான ஆலோசனைகளுக்கே மட்டுப்படுத்தப்பட்டுள்ளது."


# -----------------------------
# Domain / Location Guards
# -----------------------------
KURUNEGALA_TERMS = {
    "kurunegala", "කුරුණෑගල", "குருநாகல்"
}

NON_KURUNEGALA_TERMS = {
    "colombo", "කොළඹ", "கொழும்பு",
    "gampaha", "ගම්පහ", "கம்பஹா",
    "kandy", "මහනුවර", "கண்டி",
    "galle", "ගාල්ල", "காலி",
    "matara", "මාතර", "மாத்தறை",
    "jaffna", "යාපනය", "யாழ்ப்பாணம்",
    "batticaloa", "මඩකලපුව", "மட்டக்களப்பு",
    "anuradhapura", "අනුරාධපුර", "அனுராதபுரம்",
    "polonnaruwa", "පොළොන්නරුව", "பொலன்னறுவை",
    "badulla", "බදුල්ල", "பதுளை",
    "ratnapura", "රත්නපුර", "இரத்தினபுரி",
    "kalutara", "කළුතර", "களுத்துறை",
    "trincomalee", "ත්‍රිකුණාමලය", "திருகோணமலை",
    "hambantota", "හම්බන්තොට", "அம்பாந்தோட்டை",
    "ampara", "අම්පාර", "அம்பாறை",
    "nuwara eliya", "නුවරඑළිය", "நுவரெலியா",
    "vavuniya", "වව්නියා", "வவுனியா",
    "kilinochchi", "කිලිනොච්චි", "கிளிநொச்சி",
    "mannar", "මන්නාරම", "மன்னார்",
    "puttalam", "පුත්තලම", "புத்தளம்",
    "kegalle", "කෑගල්ල", "கேகாலை",
    "monaragala", "මොනරාගල", "மொணராகலை",
}

NON_DOMAIN_TERMS = {
    # English
    "car", "bike", "phone", "laptop", "school", "exam", "movie", "music",
    "politics", "election", "cricket", "football", "passport", "bank", "insurance",
    "bus", "train", "airport", "visa", "hotel", "restaurant", "computer", "wifi",
    "bitcoin", "tax", "loan", "job", "university", "doctor", "hospital",
    "weather", "score", "match", "flight", "ticket", "salary", "mobile", "camera","oil","world",

    # Sinhala
    "කාර්", "බයික්", "ෆෝන්", "ලැප්ටොප්", "පාසල", "විභාග", "චිත්‍රපට",
    "දේශපාලන", "ක්‍රිකට්", "පාස්පෝට්", "බැංකු", "රක්ෂණ",
    "බස්", "දුම්රිය", "ගුවන් තොටුපළ", "විසා", "හෝටල", "ආපනශාලා",
    "කම්පියුටර්", "වයිෆයි", "බදු", "ණය", "රැකියා", "විශ්වවිද්‍යාල",
    "වෛද්‍ය", "රෝහල", "කාලගුණය", "ලකුණු", "ගුවන් ගමන්", "ටිකට්", "වැටුප්",
    "ජංගම", "කැමරා","තෙල්","ලෝකය",

    # Tamil
    "கார்", "பைக்", "தொலைபேசி", "லாப்டாப்", "பாடசாலை", "தேர்வு",
    "திரைப்படம்", "அரசியல்", "கிரிக்கெட்", "காப்பீடு", "வங்கி", "பாஸ்போர்ட்",
    "பஸ்", "ரயில்", "விமான நிலையம்", "விசா", "ஹோட்டல்", "உணவகம்",
    "கம்ப்யூட்டர்", "வைஃபை", "வரி", "கடன்", "வேலை", "பல்கலைக்கழகம்",
    "மருத்துவர்", "மருத்துவமனை", "வானிலை", "மதிப்பெண்", "விமானம்", "டிக்கெட்",
    "சம்பளம்", "மொபைல்", "கேமரா","எண்ணெய்","உலகம்"
}


# -----------------------------
# Helpers
# -----------------------------
def _fallback_text(lang: str) -> str:
    return FALLBACK_TA if lang == "ta" else FALLBACK_SI


def _clarify_text(lang: str) -> str:
    return CLARIFY_TA if lang == "ta" else CLARIFY_SI


def _location_fallback_text(lang: str) -> str:
    return LOCATION_FALLBACK_TA if lang == "ta" else LOCATION_FALLBACK_SI


def _json_response(
    reply: str,
    match_type: str,
    category: str,
    language: str,
    source_id: str = "",
    confidence: float = 0.0,
    answer_source: str = "",
    debug_hits=None,
):
    payload = {
        "reply": reply,
        "match_type": match_type,
        "category": category,
        "language": language,
        "source_id": source_id,
        "confidence": round(float(confidence), 4),
        "answer_source": answer_source,
    }
    if DEBUG and debug_hits is not None:
        payload["debug_hits"] = debug_hits
    return JSONResponse(content=payload)


def _contains_any_phrase(text: str, phrases: set[str]) -> bool:
    t = normalize(text).lower()
    phrases_sorted = sorted((p.lower() for p in phrases), key=len, reverse=True)
    return any(p in t for p in phrases_sorted)


def _is_outside_kurunegala(text: str) -> bool:
    t = normalize(text).lower()

    if _contains_any_phrase(t, KURUNEGALA_TERMS):
        return False

    if _contains_any_phrase(t, NON_KURUNEGALA_TERMS):
        return True

    return False


def _is_explicitly_non_domain(text: str) -> bool:
    return _contains_any_phrase(text, NON_DOMAIN_TERMS)


@app.on_event("startup")
def startup_checks():
    if FALLBACK_THRESHOLD > CLARIFY_THRESHOLD:
        raise ValueError("FALLBACK_THRESHOLD cannot be greater than CLARIFY_THRESHOLD")

    logger.info(
        {
            "event": "startup",
            "use_fine_tuned_model": USE_FINE_TUNED_MODEL,
            "fallback_threshold": FALLBACK_THRESHOLD,
            "clarify_threshold": CLARIFY_THRESHOLD,
            "debug": DEBUG,
        }
    )


@app.get("/health")
def health():
    return {
        "status": "ok",
        "use_fine_tuned_model": USE_FINE_TUNED_MODEL,
        "fine_tuned_model_available": generate_grounded_answer is not None,
        "fallback_threshold": FALLBACK_THRESHOLD,
        "clarify_threshold": CLARIFY_THRESHOLD,
        "debug": DEBUG,
    }


if DEBUG:
    @app.get("/test-firestore/{doc_id}")
    def test_firestore(doc_id: str):
        try:
            doc = get_advice_by_id(doc_id)
            if not doc:
                return {"ok": False, "error": "Document not found", "doc_id": doc_id}
            return {"ok": True, "doc_id": doc_id, "doc": doc}
        except Exception as e:
            return {"ok": False, "error": str(e), "doc_id": doc_id}


@app.post("/chat")
def chat(req: ChatRequest):
    msg = (req.message or "").strip()
    lang = (req.language or "").strip().lower()

    if lang not in {"si", "ta"}:
        raise HTTPException(status_code=400, detail="Invalid language. Use 'si' or 'ta'.")

    if not msg:
        return _json_response(
            reply=_clarify_text(lang),
            match_type="fallback",
            category="empty_input",
            language=lang,
            source_id="",
            confidence=0.0,
            answer_source="guard",
        )

    user_q = normalize(msg)

    # -----------------------------
    # Smalltalk
    # -----------------------------
    kind = detect_smalltalk(user_q, lang)
    if kind:
        return _json_response(
            reply=smalltalk_reply(kind, lang),
            match_type="smalltalk",
            category="",
            language=lang,
            source_id="",
            confidence=1.0,
            answer_source="smalltalk",
        )

    # -----------------------------
    # Location guard
    # -----------------------------
    if _is_outside_kurunegala(user_q):
        return _json_response(
            reply=_location_fallback_text(lang),
            match_type="fallback",
            category="out_of_scope_location",
            language=lang,
            source_id="",
            confidence=0.0,
            answer_source="guard",
        )

    # -----------------------------
    # Explicit non-domain guard
    # -----------------------------
    if _is_explicitly_non_domain(user_q):
        return _json_response(
            reply=_fallback_text(lang),
            match_type="fallback",
            category="out_of_domain",
            language=lang,
            source_id="",
            confidence=0.0,
            answer_source="guard",
        )

    best = None
    source = ""
    confidence = 0.0
    category = ""
    debug_hits = None

    # -----------------------------
    # Exact Match
    # -----------------------------
    if lang == "si" and user_q in EXACT_SI:
        best = EXACT_SI[user_q]
        source = "exact"
        confidence = 1.0

    elif lang == "ta" and user_q in EXACT_TA:
        best = EXACT_TA[user_q]
        source = "exact"
        confidence = 1.0

    else:
        # -----------------------------
        # Semantic Search
        # -----------------------------
        try:
            hits = search(user_q, lang=lang, k=5)
        except Exception as e:
            logger.exception("Semantic search failed: %s", e)
            return _json_response(
                reply=_fallback_text(lang),
                match_type="error",
                category="system_error",
                language=lang,
                source_id="",
                confidence=0.0,
                answer_source="error",
            )

        if DEBUG:
            debug_hits = [
                {
                    "id": h["id"],
                    "score": round(h["score"], 4),
                    "category": h["item"].get("category", ""),
                    "matched_question": h["matched_question"],
                }
                for h in hits[:3]
            ]

        if not hits:
            return _json_response(
                reply=_fallback_text(lang),
                match_type="fallback",
                category="unknown",
                language=lang,
                source_id="",
                confidence=0.0,
                answer_source="semantic",
                debug_hits=debug_hits,
            )

        best_hit = hits[0]
        top = float(best_hit["score"])
        best = best_hit["item"]
        category = best.get("category", "general")
        confidence = top

        if top < FALLBACK_THRESHOLD:
            return _json_response(
                reply=_fallback_text(lang),
                match_type="fallback",
                category=category,
                language=lang,
                source_id=best_hit.get("id", ""),
                confidence=top,
                answer_source="semantic",
                debug_hits=debug_hits,
            )

        if FALLBACK_THRESHOLD <= top < CLARIFY_THRESHOLD:
            return _json_response(
                reply=_clarify_text(lang),
                match_type="clarification",
                category=category,
                language=lang,
                source_id=best_hit.get("id", ""),
                confidence=top,
                answer_source="semantic",
                debug_hits=debug_hits,
            )

        source = "semantic"

    # -----------------------------
    # Firestore-backed Answer Selection
    # -----------------------------
    doc = None
    source_id = ""
    answer_source = "dataset"

    if isinstance(best, dict):
        source_id = str(best.get("id", "")).strip()
        category = best.get("category", category)

        if source_id:
            try:
                doc = get_advice_by_id(source_id)
            except Exception as e:
                logger.exception("Firestore lookup failed for source_id=%s: %s", source_id, e)
                doc = None

    if doc and isinstance(doc, dict):
        context_answer = doc.get("answer_ta", "") if lang == "ta" else doc.get("answer_si", "")
        category = doc.get("category", category)
        answer_source = "firestore"
    else:
        context_answer = best.get("answer_ta", "") if lang == "ta" else best.get("answer_si", "")

    if not context_answer:
        return _json_response(
            reply=_fallback_text(lang),
            match_type="fallback",
            category=category or "unknown",
            language=lang,
            source_id=source_id,
            confidence=confidence,
            answer_source=answer_source,
            debug_hits=debug_hits,
        )

    # -----------------------------
    # Optional Qwen Output Layer
    # -----------------------------
    used_qwen = False
    if USE_FINE_TUNED_MODEL and generate_grounded_answer is not None and source == "semantic":
        try:
            final_reply = generate_grounded_answer(user_q, context_answer, lang)
            used_qwen = True
        except Exception as e:
            logger.exception("Qwen grounded generation failed: %s", e)
            final_reply = context_answer
    else:
        final_reply = context_answer

    logger.info(
        {
            "message": msg,
            "normalized": user_q,
            "language": lang,
            "match_type": source,
            "source_id": source_id,
            "category": category,
            "confidence": round(confidence, 4),
            "answer_source": answer_source,
            "used_qwen": used_qwen,
        }
    )

    return _json_response(
        reply=final_reply,
        match_type=source,
        category=category,
        language=lang,
        source_id=source_id,
        confidence=confidence,
        answer_source=answer_source,
        debug_hits=debug_hits,
    )