"""
Flare – Chat Handler (state-machine + header session)
"""

from __future__ import annotations
import json, re
from typing import Dict, List
from fastapi import APIRouter, HTTPException, Request
from pydantic import BaseModel
from config_provider import ConfigProvider, VersionConfig, IntentConfig, ParameterConfig
from prompt_builder import (
    build_detection_prompt, build_param_extract_prompt,
    build_missing_param_prompt, build_api_humanize_prompt)
from validation_engine import validate
from api_executor import call_api
from session import session_store, Session
from utils import log

cfg=ConfigProvider.get()
router=APIRouter()

_cancel_words=re.compile(r"\b(vazgeç|iptal|boşver|cancel)\b",re.I)

# -------- helper ----------
def detect_intent(version: VersionConfig, text: str) -> IntentConfig | None:
    for it in version.intents:
        prompt=build_detection_prompt(version.general_prompt,it)
        if it.name.lower() in text.lower():   #  placeholder: ask_llm(prompt,text,"classification")
            return it
    return None

# --------- endpoints -------
class SessionStartRequest(BaseModel):
    project_name:str
class SessionStartResponse(BaseModel):
    session_id:str

@router.post("/start_session",response_model=SessionStartResponse)
def start_session(body:SessionStartRequest):
    s=session_store.create_session(body.project_name)
    return SessionStartResponse(session_id=s.session_id)

class ChatRequest(BaseModel):
    user_input:str
class ChatResponse(BaseModel):
    reply:str
    session:Dict

@router.post("/chat",response_model=ChatResponse)
def chat(req:Request, body:ChatRequest):
    sid=req.headers.get("X-Session-ID")
    if not sid: raise HTTPException(400,"X-Session-ID header missing")
    s=session_store.get_session(sid)
    if not s: raise HTTPException(404,"Session not found")

    version=_get_live_version(s.project_name)
    user_text=body.user_input
    s.add_turn("user",user_text)

    # quick cancel
    if _cancel_words.search(user_text):
        s.reset_flow()
        reply="Elbette, başka bir konuda nasıl yardımcı olabilirim?"
        s.add_turn("assistant",reply)
        return ChatResponse(reply=reply,session=s.__dict__)

    # ---- idle state: intent arar
    if s.state=="idle":
        intent=detect_intent(version,user_text)
        if not intent:
            reply="(LLM-sohbet cevabı)"  # burada ask_llm kullanılacak
            s.add_turn("assistant",reply)
            return ChatResponse(reply=reply,session=s.__dict__)

        s.last_intent=intent.name
        s.state="await_param"
        s.awaiting_parameters=[p.name for p in intent.parameters]
        s.variables={}     # yeni intentte öncekileri sıfırla

    # ---- await_param state
    if s.state=="await_param":
        intent=next(i for i in version.intents if i.name==s.last_intent)
        # intent değişti mi?
        new_int=detect_intent(version,user_text)
        if new_int and new_int.name!=intent.name:
            log("🔄 new intent overrides current flow")
            s.reset_flow()
            s.last_intent=new_int.name
            s.state="await_param" if new_int.parameters else "call_api"
            s.awaiting_parameters=[p.name for p in new_int.parameters]
            intent=new_int

        # param extraction
        for p in intent.parameters:
            if p.name in s.variables: continue
            if p.name in user_text.lower():    # basit demo extraction
                val=user_text
                if not validate(val,p):
                    reply=p.invalid_prompt or f"{p.caption or p.name} değerini doğrulayamadım."
                    s.add_turn("assistant",reply)
                    return ChatResponse(reply=reply,session=s.__dict__)
                s.variables[p.name]=val
                s.awaiting_parameters.remove(p.name)

        if s.awaiting_parameters:
            s.missing_ask_count+=1
            if s.missing_ask_count>=2:
                s.reset_flow()
                reply="Başka bir konuda yardımcı olabilir miyim?"
                s.add_turn("assistant",reply)
                return ChatResponse(reply=reply,session=s.__dict__)

            ask=build_missing_param_prompt(s.awaiting_parameters)
            s.add_turn("assistant",ask)
            return ChatResponse(reply=ask,session=s.__dict__)

        s.state="call_api"

    # ---- call_api state
    if s.state=="call_api":
        intent=next(i for i in version.intents if i.name==s.last_intent)
        api=cfg.get_api(intent.action)
        if not api: raise HTTPException(500,"API not found")

        try:
            resp=call_api(api,s.variables)
        except Exception as e:
            log(f"❌ API error {e}")
            s.reset_flow()
            reply=intent.fallback_error_prompt or "Hata oluştu."
            s.add_turn("assistant",reply)
            return ChatResponse(reply=reply,session=s.__dict__)

        s.api_raw=resp.json()  # debug
        s.state="humanize"

    # ---- humanize
    if s.state=="humanize":
        intent=next(i for i in version.intents if i.name==s.last_intent)
        api=cfg.get_api(intent.action)
        human_prompt=build_api_humanize_prompt(
            version.general_prompt,
            api.response_prompt or "",
            json.dumps(s.api_raw,ensure_ascii=False,indent=2)
        )
        reply="(LLM-humanize)"   # burada ask_llm kullanılacak
        s.add_turn("assistant",reply)
        s.reset_flow()
        return ChatResponse(reply=reply,session=s.__dict__)


def _get_live_version(project_name:str)->VersionConfig:
    proj=next(p for p in cfg.projects if p.name==project_name and p.enabled)
    return max((v for v in proj.versions if v.published),key=lambda x:x.id)