from __future__ import annotations

import json
import re

from app.modules.rag.intent_router_v2.models import ConversationState, IntentDecision
from app.modules.rag.intent_router_v2.protocols import TextGenerator
from app.modules.rag.intent_router_v2.test_signals import has_test_focus

_CODE_FILE_PATH_RE = re.compile(
    r"\b(?:[\w.-]+/)*[\w.-]+\.(?:py|js|jsx|ts|tsx|java|kt|go|rb|php|c|cc|cpp|h|hpp|cs|swift|rs)(?!\w)\b",
    re.IGNORECASE,
)


class IntentClassifierV2:
    _GENERATE_DOCS_MARKERS = (
        "сгенерируй документац",
        "подготовь документац",
        "создай документац",
        "генерац",
        "generate documentation",
        "write documentation",
    )
    _DOCS_MARKERS = ("документац", "readme", "docs/", ".md", "spec", "runbook", "markdown")
    _CODE_MARKERS = ("по коду", "код", "класс", "метод", "функц", "модул", "пакет", "файл", "block", "блок", "handler", "endpoint")

    def __init__(self, llm: TextGenerator | None = None) -> None:
        self._llm = llm

    def classify(self, user_query: str, conversation_state: ConversationState) -> IntentDecision:
        deterministic = self._deterministic(user_query)
        if deterministic:
            return deterministic
        llm_decision = self._classify_with_llm(user_query, conversation_state)
        if llm_decision:
            return llm_decision
        return IntentDecision(intent="PROJECT_MISC", confidence=0.55, reason="fallback_project_misc")

    def _deterministic(self, user_query: str) -> IntentDecision | None:
        text = " ".join((user_query or "").lower().split())
        if any(marker in text for marker in self._GENERATE_DOCS_MARKERS):
            return IntentDecision(intent="GENERATE_DOCS_FROM_CODE", confidence=0.97, reason="deterministic_generate_docs")
        if self._looks_like_docs_question(text):
            return IntentDecision(intent="DOCS_QA", confidence=0.9, reason="deterministic_docs")
        if self._looks_like_code_question(user_query, text):
            return IntentDecision(intent="CODE_QA", confidence=0.9, reason="deterministic_code")
        return None

    def _classify_with_llm(self, user_query: str, conversation_state: ConversationState) -> IntentDecision | None:
        if self._llm is None:
            return None
        payload = json.dumps(
            {
                "message": user_query,
                "active_intent": conversation_state.active_intent,
                "last_query": conversation_state.last_query,
                "allowed_intents": ["CODE_QA", "DOCS_QA", "GENERATE_DOCS_FROM_CODE", "PROJECT_MISC"],
            },
            ensure_ascii=False,
        )
        try:
            raw = self._llm.generate("rag_intent_router_v2", payload, log_context="rag.intent_router_v2.classify").strip()
        except Exception:
            return None
        parsed = self._parse(raw)
        if parsed is None:
            return None
        return parsed

    def _parse(self, raw: str) -> IntentDecision | None:
        candidate = self._strip_code_fence(raw)
        try:
            payload = json.loads(candidate)
        except json.JSONDecodeError:
            return None
        intent = str(payload.get("intent") or "").strip().upper()
        if intent not in {"CODE_QA", "DOCS_QA", "GENERATE_DOCS_FROM_CODE", "PROJECT_MISC"}:
            return None
        return IntentDecision(
            intent=intent,
            confidence=float(payload.get("confidence") or 0.7),
            reason=str(payload.get("reason") or "llm").strip() or "llm",
        )

    def _strip_code_fence(self, text: str) -> str:
        if not text.startswith("```"):
            return text
        lines = text.splitlines()
        if len(lines) < 3 or lines[-1].strip() != "```":
            return text
        return "\n".join(lines[1:-1]).strip()

    def _looks_like_docs_question(self, text: str) -> bool:
        if self._has_code_file_path(text):
            return False
        return any(marker in text for marker in self._DOCS_MARKERS)

    def _looks_like_code_question(self, raw_text: str, lowered: str) -> bool:
        if self._has_code_file_path(raw_text):
            return True
        if has_test_focus(lowered):
            return True
        if any(marker in lowered for marker in self._DOCS_MARKERS) and not any(marker in lowered for marker in self._CODE_MARKERS):
            return False
        if any(marker in lowered for marker in self._CODE_MARKERS):
            return True
        if re.search(r"\b[A-Z][A-Za-z0-9_]{2,}(?:\.[A-Za-z_][A-Za-z0-9_]*)*\b", raw_text or ""):
            return True
        return bool(re.search(r"\b[a-z_][A-Za-z0-9_]{2,}\(", raw_text or ""))

    def _has_code_file_path(self, text: str) -> bool:
        return bool(_CODE_FILE_PATH_RE.search(text or ""))