"""
Flare – Chat Handler (REST API Only - Realtime moved to Event-Driven)
====================================================================
"""

import re, json, sys, httpx, os
from datetime import datetime
from typing import Dict, List, Optional, Any
from fastapi import APIRouter, HTTPException, Header, Request
from pydantic import BaseModel
import requests

from llm.prompt_builder import build_intent_prompt, build_parameter_prompt
from utils.logger import log_info, log_error, log_warning, log_debug
from api.api_executor import call_api as execute_api
from config.config_provider import ConfigProvider
from llm.validation_engine import validate
from chat_session.session import session_store, Session

# Initialize router
router = APIRouter()

# ─────────────────────────  GLOBAL VARS ───────────────────────── #
cfg = ConfigProvider.get()
llm_provider = None

# ─────────────────────────  HELPERS ───────────────────────── #
def _trim_response(raw: str) -> str:
    """
    Remove everything after the first logical assistant block or intent tag.
    Also strips trailing 'assistant' artifacts and prompt injections.
    """
    # Stop at our own rules if model leaked them
    for stop in ["#DETECTED_INTENT", "⚠️", "\nassistant", "assistant\n", "assistant"]:
        idx = raw.find(stop)
        if idx != -1:
            raw = raw[:idx]
    # Normalise selamlama
    raw = re.sub(r"Hoş[\s-]?geldin(iz)?", "Hoş geldiniz", raw, flags=re.IGNORECASE)
    return raw.strip()

def _safe_intent_parse(raw: str) -> tuple[str, str]:
    """Extract intent name and extra tail."""
    m = re.search(r"#DETECTED_INTENT:\s*([A-Za-z0-9_-]+)", raw)
    if not m:
        return "", raw
    name = m.group(1)
    # Remove 'assistant' suffix if exists
    if name.endswith("assistant"):
        name = name[:-9]  # Remove last 9 chars ("assistant")
        log_info(f"🔧 Removed 'assistant' suffix from intent name")
    tail = raw[m.end():]
    log_info(f"🎯 Parsed intent: {name}")
    return name, tail

# ─────────────────────────  LLM SETUP ───────────────────────── #
def setup_llm_provider():
    """Initialize LLM provider using factory pattern"""
    global llm_provider

    try:
        from llm.llm_factory import LLMFactory
        llm_provider = LLMFactory.create_provider()
        log_info("✅ LLM provider initialized successfully")
    except Exception as e:
        log_error("❌ Failed to initialize LLM provider", e)
        raise

# ─────────────────────────  LLM GENERATION ───────────────────────── #
async def llm_generate(s: Session, prompt: str, user_msg: str) -> str:
    """Call LLM provider with proper error handling"""
    global llm_provider

    if llm_provider is None:
        setup_llm_provider()

    try:
        # Get version config from session
        version = s.get_version_config()
        if not version:
            # Fallback: get from project config
            project = next((p for p in cfg.projects if p.name == s.project_name), None)
            if not project:
                raise ValueError(f"Project not found: {s.project_name}")
            version = next((v for v in project.versions if v.published), None)
            if not version:
                raise ValueError("No published version found")

        log_info(f"🚀 Calling LLM for session {s.session_id[:8]}...")
        log_info(f"📋 Prompt preview (first 200 chars): {prompt[:200]}...")

        history = s.chat_history

        # Call the configured LLM provider
        raw = await llm_provider.generate(
            user_input=user_msg,
            system_prompt=prompt,
            context=history[-10:] if history else []
        )

        log_info(f"🪄 LLM raw response: {raw[:100]}...")
        return raw

    except requests.exceptions.Timeout:
        log_warning(f"⏱️ LLM timeout for session {s.session_id[:8]}")
        raise HTTPException(status_code=504, detail="LLM request timed out")
    except Exception as e:
        log_error("❌ LLM error", e)
        raise HTTPException(status_code=500, detail=f"LLM error: {str(e)}")

# ─────────────────────────  PARAMETER EXTRACTION ───────────────────────── #
def _extract_parameters_from_response(raw: str, session: Session, intent_config) -> bool:
    """Extract parameters from the LLM response"""
    try:
        # Look for JSON block in response
        json_match = re.search(r'```json\s*(.*?)\s*```', raw, re.DOTALL)
        if not json_match:
            # Try to find JSON without code block
            json_match = re.search(r'\{[^}]+\}', raw)

        if not json_match:
            log_info("❌ No JSON found in response")
            return False

        json_str = json_match.group(1) if '```' in raw else json_match.group(0)
        params = json.loads(json_str)

        any_valid = False
        for param_name, param_value in params.items():
            # Find parameter config
            param_config = next(
                (p for p in intent_config.parameters if p.name == param_name),
                None
            )

            if not param_config:
                log_info(f"⚠️ Parameter config not found for: {param_name}")
                continue

            # Validate parameter
            if validate(str(param_value), param_config):
                session.variables[param_config.variable_name] = str(param_value)
                any_valid = True
                log_info(f"✅ Extracted {param_name}={param_value} → {param_config.variable_name}")
            else:
                log_info(f"❌ Invalid {param_name}={param_value}")

        return any_valid

    except json.JSONDecodeError as e:
        log_error("❌ JSON parsing error", e)
        log_error(f"❌ Failed to parse: {raw[:200]}")
        return False
    except Exception as e:
        log_error("❌ Parameter processing error", e)
        return False

# ─────────────────────────  API EXECUTION ───────────────────────── #
async def _execute_api_call(session: Session, intent_config) -> str:
    """Execute API call and return humanized response with better error handling"""
    try:
        session.state = "call_api"
        api_name = intent_config.action
        api_config = cfg.get_api(api_name)

        if not api_config:
            log_info(f"❌ API config not found: {api_name}")
            session.reset_flow()
            return get_user_friendly_error("api_error", {"api_name": api_name})

        log_info(f"📡 Calling API: {api_name}")
        log_info(f"📦 API variables: {session.variables}")

        # Execute API call with session
        response = execute_api(api_config, session)
        api_json = response.json()
        log_info(f"✅ API response: {api_json}")

        # Humanize response
        session.state = "humanize"
        if api_config.response_prompt:
            prompt = api_config.response_prompt.replace(
                "{{api_response}}",
                json.dumps(api_json, ensure_ascii=False)
            )
            human_response = await llm_generate(session, prompt, json.dumps(api_json))
            session.reset_flow()
            return human_response if human_response else f"İşlem sonucu: {api_json}"
        else:
            session.reset_flow()
            return f"İşlem tamamlandı: {api_json}"

    except requests.exceptions.Timeout:
        log_warning(f"⏱️ API timeout: {api_name}")
        session.reset_flow()
        return get_user_friendly_error("api_timeout")
    except Exception as e:
        log_error("❌ API call error", e)
        session.reset_flow()
        return get_user_friendly_error("api_error", {"api_name": api_name})

# ─────────────────────────  REQUEST MODELS ───────────────────────── #
class ChatRequest(BaseModel):
    message: str

class StartRequest(BaseModel):
    project_name: str
    version_no: Optional[int] = None
    is_realtime: bool = False
    locale: Optional[str] = None

class ChatResponse(BaseModel):
    session_id: str
    answer: str

# ─────────────────────────  API ENDPOINTS ───────────────────────── #
@router.post("/start_session", response_model=ChatResponse)
async def start_session(req: StartRequest, request: Request):
    """Create new session - supports both REST and realtime"""
    global llm_provider

    try:
        # Validate project exists
        project = next((p for p in cfg.projects if p.name == req.project_name and p.enabled), None)
        if not project:
            raise HTTPException(404, f"Project '{req.project_name}' not found or disabled")

        # Determine locale
        session_locale = req.locale
        if not session_locale:
            session_locale = project.default_locale

        # Validate locale is supported by project
        if session_locale not in project.supported_locales:
            raise HTTPException(
                400,
                f"Locale '{session_locale}' not supported by project. Supported: {project.supported_locales}"
            )

        # Find version
        if req.version_no:
            version = next((v for v in project.versions if v.no == req.version_no), None)
            if not version:
                raise HTTPException(404, f"Version {req.version_no} not found for project '{req.project_name}'")
        else:
            published_versions = [v for v in project.versions if v.published]
            if not published_versions:
                raise HTTPException(404, f"No published version for project '{req.project_name}'")
            version = max(published_versions, key=lambda v: v.no)

        # Create session
        session = session_store.create_session(
            project_name=req.project_name,
            version_no=version.no,
            is_realtime=req.is_realtime,
            locale=session_locale
        )
        session.set_version_config(version)

        # For realtime sessions, publish event to start the flow
        if req.is_realtime and hasattr(request.app.state, 'event_bus'):
            from chat_session.event_bus import Event, EventType

            await request.app.state.event_bus.publish(Event(
                type=EventType.SESSION_STARTED,
                session_id=session.session_id,
                data={
                    "session": session,
                    "has_welcome": bool(version.welcome_prompt),
                    "welcome_text": version.welcome_prompt or "Hoş geldiniz! Size nasıl yardımcı olabilirim?",
                    "locale": session_locale,
                    "project_name": req.project_name,
                    "version_no": version.no
                }
            ))

            # For realtime, return minimal response
            return ChatResponse(
                session_id=session.session_id,
                answer="[REALTIME_MODE] Connect via WebSocket to continue."
            )

        # For REST mode, process welcome prompt normally
        else:
            # Create LLM provider if not exists
            if not llm_provider:
                from llm.llm_factory import LLMFactory
                llm_provider = LLMFactory.create_provider()
                log_info(f"🤖 LLM Provider created: {type(llm_provider).__name__}")

            # Process welcome prompt
            greeting = "Hoş geldiniz! Size nasıl yardımcı olabilirim?"
            if version.welcome_prompt:
                log_info(f"🎉 Processing welcome prompt for session {session.session_id[:8]}...")
                try:
                    welcome_result = await llm_provider.generate(
                        user_input="",
                        system_prompt=version.welcome_prompt,
                        context=[]
                    )
                    if welcome_result and welcome_result.strip():
                        greeting = welcome_result.strip()
                except Exception as e:
                    log_error("⚠️ Welcome prompt processing failed", e)

            session.add_turn("assistant", greeting)

            log_info(f"✅ Session created for project '{req.project_name}' version {version.no}")

            return ChatResponse(session_id=session.session_id, answer=greeting)

    except HTTPException:
        raise
    except Exception as e:
        log_error("❌ Session creation error", e)
        raise HTTPException(500, f"Session creation failed: {str(e)}")

@router.post("/chat")
async def chat(req: ChatRequest, x_session_id: str = Header(...)):
    """Process chat message - REST API only (realtime uses WebSocket)"""
    try:
        # Get session
        session = session_store.get_session(x_session_id)
        if not session:
            raise HTTPException(
                status_code=404,
                detail=get_user_friendly_error("session_not_found")
            )

        # Check if this is a realtime session
        if session.is_realtime:
            raise HTTPException(
                status_code=400,
                detail="This is a realtime session. Please use WebSocket connection instead."
            )

        # Session expiry check
        if session.is_expired():
            session_store.delete_session(x_session_id)
            raise HTTPException(
                status_code=401,
                detail=get_user_friendly_error("session_expired")
            )

        # Update last activity
        session.last_activity = datetime.utcnow().isoformat()
        session_store.update_session(session)

        # Add user message to history
        session.add_message("user", req.message)
        log_info(f"💬 User [{session.session_id[:8]}...]: {req.message}")

        # Get project and version config
        project = next((p for p in cfg.projects if p.name == session.project_name), None)
        if not project:
            raise HTTPException(
                status_code=404,
                detail=get_user_friendly_error("project_not_found")
            )

        version = session.get_version_config()
        if not version:
            raise HTTPException(
                status_code=400,
                detail=get_user_friendly_error("version_not_found")
            )

        # Process based on current state
        if session.state == "idle":
            # Build intent detection prompt
            prompt = build_intent_prompt(version, session.chat_history, project.default_locale)
            raw = await llm_generate(session, prompt, req.message)

            # Check for intent
            intent_name, tail = _safe_intent_parse(raw)

            if intent_name:
                # Find intent config
                intent_config = next((i for i in version.intents if i.name == intent_name), None)

                if intent_config:
                    session.current_intent = intent_name
                    session.set_intent_config(intent_config)
                    session.state = "collect_params"
                    log_info(f"🎯 Intent detected: {intent_name}")

                    # Check if parameters were already extracted
                    if tail and _extract_parameters_from_response(tail, session, intent_config):
                        log_info("📦 Some parameters extracted from initial response")

                    # Check what parameters are missing
                    missing_params = [
                        p.name for p in intent_config.parameters
                        if p.required and p.variable_name not in session.variables
                    ]

                    if not missing_params:
                        # All required parameters collected, execute API
                        response = await _execute_api_call(session, intent_config)
                        session.add_message("assistant", response)
                        return {"response": response, "intent": intent_name, "state": "completed"}
                    else:
                        # Need to collect more parameters
                        collection_config = cfg.global_config.llm_provider.settings.get("parameter_collection_config", {})
                        max_params = collection_config.get("max_params_per_question", 2)

                        # Decide which parameters to ask
                        params_to_ask = missing_params[:max_params]

                        param_prompt = build_parameter_prompt(
                            version=version,
                            intent_config=intent_config,
                            chat_history=session.chat_history,
                            collected_params=session.variables,
                            missing_params=missing_params,
                            params_to_ask=params_to_ask,
                            max_params=max_params,
                            project_locale=project.default_locale,
                            unanswered_params=session.unanswered_parameters
                        )

                        param_question = await llm_generate(session, param_prompt, req.message)
                        clean_question = _trim_response(param_question)
                        session.add_message("assistant", clean_question)
                        return {"response": clean_question, "intent": intent_name, "state": "collecting_params"}

                else:
                    log_info(f"⚠️ Unknown intent: {intent_name}")

            # No intent detected, return general response
            clean_response = _trim_response(raw)
            session.add_message("assistant", clean_response)
            return {"response": clean_response, "state": "idle"}

        elif session.state == "collect_params":
            # Continue parameter collection
            intent_config = session.get_intent_config()

            # Try to extract parameters from user message
            param_prompt = f"""
            Extract parameters from user message: "{req.message}"

            Expected parameters:
            {json.dumps([{
                'name': p.name,
                'type': p.type,
                'required': p.required,
                'extraction_prompt': p.extraction_prompt
            } for p in intent_config.parameters if p.variable_name not in session.variables], ensure_ascii=False)}

            Return as JSON object with parameter names as keys.
            """

            raw = await llm_generate(session, param_prompt, req.message)
            _extract_parameters_from_response(raw, session, intent_config)

            # Check what parameters are still missing
            missing_params = [
                p.name for p in intent_config.parameters
                if p.required and p.variable_name not in session.variables
            ]

            if not missing_params:
                # All parameters collected, execute API
                response = await _execute_api_call(session, intent_config)
                session.add_message("assistant", response)
                return {"response": response, "intent": session.current_intent, "state": "completed"}
            else:
                # Still need more parameters
                collection_config = cfg.global_config.llm_provider.settings.get("parameter_collection_config", {})
                max_params = collection_config.get("max_params_per_question", 2)

                params_to_ask = missing_params[:max_params]

                param_prompt = build_parameter_prompt(
                    version=version,
                    intent_config=intent_config,
                    chat_history=session.chat_history,
                    collected_params=session.variables,
                    missing_params=missing_params,
                    params_to_ask=params_to_ask,
                    max_params=max_params,
                    project_locale=project.default_locale,
                    unanswered_params=session.unanswered_parameters
                )
                param_question = await llm_generate(session, param_prompt, req.message)
                clean_question = _trim_response(param_question)
                session.add_message("assistant", clean_question)
                return {"response": clean_question, "intent": session.current_intent, "state": "collecting_params"}

        else:
            # Unknown state, reset
            session.reset_flow()
            return {"response": get_user_friendly_error("internal_error"), "state": "error"}

    except HTTPException:
        raise
    except requests.exceptions.Timeout:
        log_error(f"Timeout in chat for session {x_session_id[:8]}")
        return {
            "response": get_user_friendly_error("llm_timeout"),
            "state": "error",
            "error": True
        }
    except Exception as e:
        log_error("❌ Chat error", e)
        import traceback
        traceback.print_exc()
        return {
            "response": get_user_friendly_error("internal_error"),
            "state": "error",
            "error": True
        }

@router.post("/end_session")
async def end_session(x_session_id: str = Header(...), request: Request = None):
    """End a session - works for both REST and realtime"""
    try:
        session = session_store.get_session(x_session_id)
        if not session:
            raise HTTPException(404, "Session not found")

        # For realtime sessions, publish end event
        if session.is_realtime and request and hasattr(request.app.state, 'event_bus'):
            from chat_session.event_bus import Event, EventType

            await request.app.state.event_bus.publish(Event(
                type=EventType.SESSION_ENDED,
                session_id=x_session_id,
                data={"reason": "user_request"}
            ))

        # Delete session
        session_store.delete_session(x_session_id)

        return {"message": "Session ended successfully"}

    except HTTPException:
        raise
    except Exception as e:
        log_error("❌ Error ending session", e)
        raise HTTPException(500, f"Failed to end session: {str(e)}")

# ─────────────────────────  HELPER FUNCTIONS ───────────────────────── #
def get_user_friendly_error(error_type: str, context: dict = None) -> str:
    """Get user-friendly error messages"""
    error_messages = {
        "session_not_found": "Oturumunuz bulunamadı. Lütfen yeni bir konuşma başlatın.",
        "project_not_found": "Proje konfigürasyonu bulunamadı. Lütfen yönetici ile iletişime geçin.",
        "version_not_found": "Proje versiyonu bulunamadı. Lütfen geçerli bir versiyon seçin.",
        "intent_not_found": "Üzgünüm, ne yapmak istediğinizi anlayamadım. Lütfen daha açık bir şekilde belirtir misiniz?",
        "api_timeout": "İşlem zaman aşımına uğradı. Lütfen tekrar deneyin.",
        "api_error": "İşlem sırasında bir hata oluştu. Lütfen daha sonra tekrar deneyin.",
        "parameter_validation": "Girdiğiniz bilgide bir hata var. Lütfen kontrol edip tekrar deneyin.",
        "llm_error": "Sistem yanıt veremedi. Lütfen biraz sonra tekrar deneyin.",
        "llm_timeout": "Sistem meşgul. Lütfen birkaç saniye bekleyip tekrar deneyin.",
        "session_expired": "Oturumunuz zaman aşımına uğradı. Lütfen yeni bir konuşma başlatın.",
        "rate_limit": "Çok fazla istek gönderdiniz. Lütfen biraz bekleyin.",
        "internal_error": "Beklenmeyen bir hata oluştu. Lütfen yönetici ile iletişime geçin."
    }

    message = error_messages.get(error_type, error_messages["internal_error"])

    # Context bilgisi varsa ekle
    if context:
        if error_type == "parameter_validation" and "field" in context:
            message = f"{context['field']} alanı için {message}"
        elif error_type == "api_error" and "api_name" in context:
            message = f"{context['api_name']} servisi için {message}"

    return message

def validate_parameter_with_message(param_config, value, locale="tr") -> tuple[bool, str]:
    """Validate parameter and return user-friendly message"""
    try:
        # Type validation
        if param_config.type == "int":
            try:
                int(value)
            except ValueError:
                return False, f"Lütfen geçerli bir sayı girin."

        elif param_config.type == "float":
            try:
                float(value)
            except ValueError:
                return False, f"Lütfen geçerli bir ondalık sayı girin."

        elif param_config.type == "date":
            # Date parsing with locale support
            from config.locale_manager import LocaleManager
            parsed_date = LocaleManager.parse_date_expression(value, locale)
            if not parsed_date:
                return False, f"Lütfen geçerli bir tarih girin (örn: yarın, 15 Haziran, 2025-06-15)."

        elif param_config.type == "bool":
            if value.lower() not in ["evet", "hayır", "yes", "no", "true", "false"]:
                return False, f"Lütfen 'evet' veya 'hayır' olarak cevaplayın."

        # Regex validation
        if param_config.validation_regex:
            import re
            if not re.match(param_config.validation_regex, value):
                return False, param_config.invalid_prompt or "Girdiğiniz değer geçerli formatta değil."

        return True, ""

    except Exception as e:
        log_error(f"Parameter validation error", e)
        return False, "Değer kontrol edilirken bir hata oluştu."

# Initialize LLM on module load
setup_llm_provider()