"""Chat/session API: start a one-shot session, send messages, finish + debrief."""
from __future__ import annotations

from flask import Blueprint, jsonify, request

from ..llm import LLMError
from ..services.simulator import Simulator
from .helpers import ApiError, current_user, require_auth, require_roles

chat_bp = Blueprint("chat", __name__)


def _stores():
    from flask import current_app

    return {
        "groups": current_app.extensions["group_store"],
        "sessions": current_app.extensions["session_store"],
        "llm": current_app.extensions["llm"],
    }


def _sim(group, persona):
    llm = _stores()["llm"]
    if not llm:
        raise ApiError("LLM not configured", 500)
    return Simulator(llm)


@chat_bp.post("/<gid>/personas/<pid>/chat/start")
@require_auth
@require_roles("user")
def start_session(gid: str, pid: str):
    s = _stores()
    group = s["groups"].get_or_none(gid)
    if not group or group.get("status") != "ready":
        raise ApiError("group not ready", 404)
    persona = s["groups"].get_persona(gid, pid)
    if not persona:
        raise ApiError("persona not found", 404)
    actor = current_user()
    # One-shot: reject if already finished this persona
    try:
        session = s["sessions"].create(
            user_id=actor["id"], group_id=gid, persona_id=pid,
            persona_name=persona.get("name", "?"),
            persona_meta={
                "tier": persona.get("tier"),
                "initiation_mode": persona.get("initiation_mode"),
                "channel": persona.get("channel"),
            },
        )
    except ValueError as exc:
        raise ApiError(str(exc), 400)

    sim = _sim(group, persona)
    # Seller-initiated: give the trainee an opening task (no persona message yet).
    init_mode = persona.get("initiation_mode", "customer")
    if init_mode == "customer":
        # Customer opens: inject the persona's opener as the first message.
        opener = persona.get("opener") or "Hi, I saw your product and had a question."
        s["sessions"].update(session["id"], messages=[{"role": "customer", "text": opener}])
    else:
        s["sessions"].update(
            session["id"],
            task="The customer did NOT message first. You must open the sale — start the "
                 "conversation with this lead (e.g. introduce yourself and engage with interest).",
        )
    return jsonify({"session": s["sessions"].get(session["id"]), "initiation_mode": init_mode})


@chat_bp.post("/<gid>/personas/<pid>/chat/send")
@require_auth
@require_roles("user")
def send_message(gid: str, pid: str):
    s = _stores()
    actor = current_user()
    session = s["sessions"].active_for_persona(actor["id"], pid)
    if not session or session.get("group_id") != gid:
        raise ApiError("no active session for this persona", 404)

    data = request.get_json(silent=True) or {}
    text = (data.get("text") or "").strip()
    if not text:
        raise ApiError("message is empty")
    if len(text) > 2000:
        raise ApiError("message too long")

    group = s["groups"].get_or_none(gid)
    persona = s["groups"].get_persona(gid, pid)
    messages = list(session.get("messages", []))
    messages.append({"role": "seller", "text": text})

    sim = _sim(group, persona)
    try:
        reply = sim.persona_reply(
            persona=persona,
            sales_kit=group.get("sales_kit") or {},
            messages=messages,
            internal=session.get("internal", {}),
        )
    except LLMError as exc:
        raise ApiError(f"LLM error: {exc}", 500)
    messages.append({"role": "customer", "text": reply})

    s["sessions"].update(session["id"], messages=messages)
    return jsonify({"reply": reply, "messages": messages})


@chat_bp.post("/<gid>/personas/<pid>/chat/finish")
@require_auth
@require_roles("user")
def finish_session(gid: str, pid: str):
    """End the chat and produce the debrief via the judge-LLM (reveals latent fields)."""
    s = _stores()
    actor = current_user()
    session = s["sessions"].active_for_persona(actor["id"], pid)
    if not session or session.get("group_id") != gid:
        raise ApiError("no active session for this persona", 404)
    group = s["groups"].get_or_none(gid)
    persona = s["groups"].get_persona(gid, pid)

    sim = _sim(group, persona)
    messages = session.get("messages", [])
    try:
        verdict = sim.judge(persona=persona, messages=messages)
    except LLMError as exc:
        raise ApiError(f"LLM error: {exc}", 500)

    outcome = "won" if verdict.get("outcome") == "won" else "lost"
    debrief = {
        **verdict,
        "revealed_persona": {
            "pains": persona.get("pains", []),
            "income": persona.get("income", ""),
            "personality": persona.get("personality", ""),
            "budget": persona.get("budget", ""),
            "negotiation_levers": persona.get("negotiation_levers", []),
            "opener": persona.get("opener", ""),
            "background": persona.get("background", ""),
        },
    }
    s["sessions"].update(
        session["id"],
        status="finished",
        outcome=outcome,
        debrief=debrief,
        internal=session.get("internal", {}),
    )
    return jsonify({"session": s["sessions"].get(session["id"]), "debrief": debrief})


@chat_bp.get("/sessions")
@require_auth
@require_roles("user")
def my_sessions():
    s = _stores()
    uid = current_user()["id"]
    sessions = s["sessions"].list_for_user(uid)
    return jsonify({"sessions": sessions})


@chat_bp.get("/sessions/<sid>")
@require_auth
@require_roles("user")
def get_session(sid: str):
    s = _stores()
    session = s["sessions"].get_or_none(sid)
    if not session or session.get("user_id") != current_user()["id"]:
        raise ApiError("session not found", 404)
    return jsonify({"session": session})