"""
Routing utilities that decide whether a query should hit RAG or stay in small-talk.
"""
from __future__ import annotations

import re
from dataclasses import dataclass, field
from enum import Enum
from typing import Dict, Optional


class IntentRoute(str, Enum):
    """High-level route for the chatbot pipeline."""

    GREETING = "greeting"
    SMALL_TALK = "small_talk"
    SEARCH = "search"


DOCUMENT_CODE_PATTERNS = [
    r"264[-\s]?QD[-\s]?TW",
    r"QD[-\s]?69[-\s]?TW",
    r"TT[-\s]?02[-\s]?CAND",
    r"TT[-\s]?02[-\s]?BIEN[-\s]?SOAN",
    r"QUYET[-\s]?DINH[-\s]?69",
    r"QUYET[-\s]?DINH[-\s]?264",
    r"THONG[-\s]?TU[-\s]?02",
]

SMALL_TALK_PHRASES = [
    "mệt quá",
    "nhàm chán",
    "tâm sự",
    "chém gió",
    "đang làm gì",
    "chuyện trò",
    "trò chuyện",
    "hỏi chơi thôi",
]


def _has_document_code(query: str) -> bool:
    normalized = query.upper()
    return any(re.search(pattern, normalized) for pattern in DOCUMENT_CODE_PATTERNS)


def _flag_keywords(query_lower: str) -> Dict[str, bool]:
    return {
        "greeting": any(
            phrase in query_lower for phrase in ["xin chào", "xin chao", "chào", "chao", "hello", "hi"]
        ),
        "fine": any(
            kw in query_lower
            for kw in ["mức phạt", "phạt", "vi phạm", "đèn đỏ", "nồng độ cồn", "mũ bảo hiểm", "tốc độ"]
        ),
        "procedure": any(
            kw in query_lower for kw in ["thủ tục", "thu tuc", "hồ sơ", "ho so", "điều kiện", "dieu kien", "cư trú", "cu tru"]
        ),
        "advisory": any(kw in query_lower for kw in ["cảnh báo", "lua dao", "lừa đảo", "scam", "mạo danh", "thủ đoạn"]),
        "office": any(kw in query_lower for kw in ["địa chỉ", "dia chi", "công an", "cong an", "điểm tiếp dân", "số điện thoại"]),
        "legal": any(
            kw in query_lower
            for kw in [
                "quyết định",
                "thông tư",
                "nghị quyết",
                "kỷ luật",
                "qd 69",
                "qd 264",
                "thông tư 02",
                "điều lệnh",
                "văn bản pháp luật",
            ]
        ),
        "small_talk": any(phrase in query_lower for phrase in SMALL_TALK_PHRASES),
    }


@dataclass
class RouteDecision:
    route: IntentRoute
    intent: str
    confidence: float
    rationale: str
    forced_intent: Optional[str] = None
    keyword_flags: Dict[str, bool] = field(default_factory=dict)


def decide_route(query: str, intent: str, confidence: float) -> RouteDecision:
    """
    Decide how the chatbot should handle the query before invoking RAG.
    """
    query_lower = query.lower().strip()
    words = query_lower.split()
    keyword_flags = _flag_keywords(query_lower)
    has_doc_code = _has_document_code(query_lower)

    route = IntentRoute.SEARCH
    rationale = "default-search"
    forced_intent: Optional[str] = None

    doc_code_override = False
    if has_doc_code and intent != "search_legal":
        forced_intent = "search_legal"
        rationale = "doc-code-detected"
        route = IntentRoute.SEARCH
        doc_code_override = True

    greeting_candidate = (
        len(words) <= 3 and keyword_flags["greeting"] and not any(
            keyword_flags[key] for key in ["fine", "procedure", "advisory", "office", "legal"]
        )
    )
    if greeting_candidate and intent == "greeting" and not doc_code_override:
        route = IntentRoute.GREETING
        rationale = "simple-greeting"
        forced_intent = "greeting"
    elif (
        not doc_code_override
        and keyword_flags["small_talk"]
        and not any(keyword_flags[key] for key in ["fine", "procedure", "advisory", "office", "legal"])
    ):
        route = IntentRoute.SMALL_TALK
        rationale = "small-talk-keywords"
        forced_intent = "general_query"
    elif not doc_code_override and (intent == "general_query" or confidence < 0.55):
        # Generic small talk / low confidence
        route = IntentRoute.SMALL_TALK
        rationale = "general-or-low-confidence"

    if route != IntentRoute.GREETING and not doc_code_override:
        keyword_force_map = [
            ("legal", "search_legal"),
            ("fine", "search_fine"),
            ("procedure", "search_procedure"),
            ("advisory", "search_advisory"),
            ("office", "search_office"),
        ]
        for flag, target_intent in keyword_force_map:
            if forced_intent:
                break
            if keyword_flags.get(flag) and intent != target_intent:
                forced_intent = target_intent
                route = IntentRoute.SEARCH
                rationale = f"keyword-override-{flag}"
                break

    return RouteDecision(
        route=route,
        intent=intent,
        confidence=confidence,
        rationale=rationale,
        forced_intent=forced_intent,
        keyword_flags=keyword_flags,
    )