api/main.py

"""
PriceOye AI Phone Advisor — FastAPI Backend
============================================
Endpoints:
  POST /chat          — send a message, get response + phone cards
  GET  /phones        — full phone database
  GET  /phone/{id}    — single phone detail
  GET  /health        — health check

Deploy: uvicorn api.main:app --host 0.0.0.0 --port 7860
"""

from fastapi import FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
from typing import Optional
import uuid

from src.conversation import (
    ConversationState, handle_message, get_greeting, format_phone_summary
)
from src.phone_database import build_database
from src.scoring_engine import get_category_scores, get_sub_scores

app = FastAPI(
    title="PriceOye AI Phone Advisor",
    description="ML-powered phone recommendation engine for Pakistan's market",
    version="2.0.0",
)

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_methods=["*"],
    allow_headers=["*"],
)

# In-memory session store (replace with Redis for production)
SESSIONS: dict[str, ConversationState] = {}
PHONE_DB = build_database()


# ─────────────────────────────────────────────
#  SCHEMAS
# ─────────────────────────────────────────────

class ChatRequest(BaseModel):
    session_id: Optional[str] = None
    message: str


class ChatResponse(BaseModel):
    session_id: str
    text: str
    followup: Optional[str] = None
    quick_replies: list[str]
    phones: Optional[list[dict]] = None


# ─────────────────────────────────────────────
#  ENDPOINTS
# ─────────────────────────────────────────────

@app.get("/health")
def health():
    return {"status": "ok", "phones_in_db": len(PHONE_DB), "version": "2.0.0"}


@app.post("/chat", response_model=ChatResponse)
def chat(req: ChatRequest):
    # Create or retrieve session
    session_id = req.session_id or str(uuid.uuid4())

    if session_id not in SESSIONS or req.session_id is None:
        # New session — return greeting
        greeting = get_greeting()
        SESSIONS[session_id] = greeting["state"]
        return ChatResponse(
            session_id=session_id,
            text=greeting["text"],
            quick_replies=greeting["quick_replies"],
            phones=None,
        )

    state = SESSIONS[session_id]
    response = handle_message(req.message, state)
    SESSIONS[session_id] = response["state"]

    return ChatResponse(
        session_id=session_id,
        text=response["text"],
        followup=response.get("followup"),
        quick_replies=response.get("quick_replies", []),
        phones=response.get("phones"),
    )


@app.get("/phones")
def list_phones():
    return [
        {
            "id": p.id,
            "name": p.name,
            "brand": p.brand,
            "os": p.os,
            "price_pkr": p.price_pkr,
            "price_label": p.price_label,
            "emoji": p.emoji,
            "tags": p.tags,
            "priceoye_url": p.priceoye_url,
            "whatmobile_url": p.whatmobile_url,
            "category_scores": {k: round(v, 1) for k, v in get_category_scores(p).items()},
        }
        for p in PHONE_DB
    ]


@app.get("/phone/{phone_id}")
def get_phone(phone_id: str, category: str = "camera"):
    phone = next((p for p in PHONE_DB if p.id == phone_id), None)
    if not phone:
        raise HTTPException(status_code=404, detail="Phone not found")

    cats = get_category_scores(phone)
    return {
        "id": phone.id,
        "name": phone.name,
        "brand": phone.brand,
        "os": phone.os,
        "price_pkr": phone.price_pkr,
        "price_label": phone.price_label,
        "emoji": phone.emoji,
        "tags": phone.tags,
        "highlights": phone.highlights,
        "priceoye_url": phone.priceoye_url,
        "whatmobile_url": phone.whatmobile_url,
        "category_scores": {k: round(v, 1) for k, v in cats.items()},
        "deep_dive": {
            "category": category,
            "scores": get_sub_scores(phone, category),
        },
    }