"""
Flare – Chat Handler (start_session & chat)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Intent → Parametre → API → Humanize akışı
"""

from __future__ import annotations

import json
from typing import Dict, Optional

from fastapi import APIRouter, HTTPException
from pydantic import BaseModel

from config_provider import ConfigProvider, VersionConfig
from prompt_builder import build_intent_prompt, build_param_prompt, build_api_humanize_prompt
from api_executor import call_api
from session import session_store, Session
from utils import log

cfg = ConfigProvider.get()

router = APIRouter()


# --------- Body models ----------
class SessionStartRequest(BaseModel):
    project_name: str


class SessionStartResponse(BaseModel):
    session_id: str


class ChatRequest(BaseModel):
    session_id: str
    user_input: str


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


# --------- LLM stub -------------
def ask_llm(prompt: str, user_input: str = "", mode: str = "text"):
    log(f"🤖 [LLM-stub] mode={mode} prompt_len={len(prompt)}")
    if mode == "classification":
        return ""
    if mode == "json":
        return {}
    return "LLM yanıtı (stub)."


# --------- Helpers --------------
def _get_live_version(project_name: str) -> VersionConfig:
    proj = next((p for p in cfg.projects if p.name == project_name and p.enabled), None)
    if proj is None:
        raise HTTPException(status_code=400, detail="Project not found or disabled")
    v = max((v for v in proj.versions if v.published), key=lambda x: x.id, default=None)
    if v is None:
        raise HTTPException(status_code=400, detail="No published version")
    return v


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


@router.post("/chat", response_model=ChatResponse)
def chat(body: ChatRequest):
    session: Session | None = session_store.get_session(body.session_id)
    if session is None:
        raise HTTPException(status_code=404, detail="Session not found")

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

    # 1) Intent detection loop
    intent = None
    for it in version.intents:
        prompt = build_intent_prompt(version.general_prompt, it)
        resp = ask_llm(prompt, user_input, mode="classification")
        if it.name.lower() in resp.lower():
            intent = it
            break

    if intent is None:
        reply = ask_llm(version.general_prompt, user_input)
        session.add_turn("assistant", reply)
        return ChatResponse(reply=reply, session=session.to_dict())

    # 2) Parameter extraction
    vars_ = session.variables.copy()
    missing = [p for p in intent.parameters if p.name not in vars_]
    if missing:
        prompt = build_param_prompt(version.general_prompt, intent, missing)
        llm_json = ask_llm(prompt, user_input, mode="json") or {}
        vars_.update(llm_json)

    still_missing = [p.name for p in intent.parameters if p.required and p.name not in vars_]
    if still_missing:
        ask = " ".join(f"{p} değerini söyler misin?" for p in still_missing)
        reply = ask_llm(version.general_prompt, ask)
        session.variables = vars_
        session.awaiting_parameters = still_missing
        session.add_turn("assistant", reply)
        return ChatResponse(reply=reply, session=session.to_dict())

    # 3) API call
    api_cfg = cfg.get_api(intent.action)
    if api_cfg is None:
        raise HTTPException(status_code=500, detail="API not configured")

    try:
        resp = call_api(api_cfg, vars_)
    except Exception as e:
        log(f"❌ API error: {e}")
        reply = intent.fallback_error_prompt or "İşlem sırasında hata oluştu."
        session.add_turn("assistant", reply)
        return ChatResponse(reply=reply, session=session.to_dict())

    # 4) Humanize
    human_prompt = build_api_humanize_prompt(
        version.general_prompt,
        api_cfg.response_prompt or "",
        json.dumps(resp.json(), ensure_ascii=False, indent=2),
    )
    reply = ask_llm(human_prompt)
    session.variables = vars_
    session.add_turn("assistant", reply)
    return ChatResponse(reply=reply, session=session.to_dict())