api/app.py

# python -m uvicorn main:app --reload

from __future__ import annotations
from typing import Any, Dict, List, Optional
import os
import traceback
import joblib
import numpy as np
import pandas as pd
from fastapi import FastAPI, HTTPException, Request
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel, Field

APP_DIR = os.path.dirname(os.path.abspath(__file__))
ROOT_DIR = os.path.dirname(APP_DIR)
MODEL_PATH = os.path.join(ROOT_DIR, "ai", "models", "stacking_fraude_model_4.pkl")
THRESHOLDS_PATH = os.path.join(ROOT_DIR, "ai", "models", "thresholds.json")
FEATHER_DATASET = os.path.join(ROOT_DIR, "data", "final_dataset.feather")
PARQUET_DATASET = os.path.join(ROOT_DIR, "data", "final_dataset.parquet")

DROP_COLS = {
	"card_hash",
	"terminal_id",
	"is_fraud",
}


class TransactionBody(BaseModel):
	features: Dict[str, Any] = Field(default_factory=dict)


class BatchBody(BaseModel):
	items: List[Dict[str, Any]]


_MODEL = None
_FEATURES: Optional[List[str]] = None
_CARD_MEDIANS: Dict[str, Dict[str, float]] = {}
_TERM_MEDIANS: Dict[str, Dict[str, float]] = {}
_CARD_IDS: Optional[set] = None
_TERM_IDS: Optional[set] = None
_ACTIVE_THRESHOLD: float = 0.5


CARD_FEATURES = {
	"dias_desde_primeira_transacao_do_cartao",
	"qtas_transacoes_cartao_dia",
	"qtas_fraudes_cartao",
	"valor_medio_cartao",
	"desvio_padrao_valor_cartao",
	"entropia_geografica_cartao",
	"fraude_ratio_cartao",
	"tempo_medio_denuncia_cartao",
	"velocidade_ultima_transacao",
}

TERMINAL_FEATURES = {
	"dias_desde_inicio_terminal",
	"qtas_transacoes_terminal_dia",
	"qtas_fraudes_terminal",
	"valor_medio_terminal",
	"desvio_padrao_valor_terminal",
	"fraude_ratio_terminal",
	"tempo_medio_denuncia_terminal",
}


def _normalize_id(val: Optional[Any]) -> Optional[str]:
    if val is None:
        return None
    s = str(val).strip()
    if s.endswith('.0'):
        s = s[:-2]
    return s


def _predict(ensemble, X: pd.DataFrame) -> Dict[str, Any]:
	global _ACTIVE_THRESHOLD
	y_prob = ensemble.predict_proba(X) if hasattr(ensemble, "predict_proba") else None
	items: List[Dict[str, Any]] = []
	if y_prob is not None:
		for i in range(len(X)):
			pp = y_prob[i]
			if isinstance(pp, (list, np.ndarray)) and len(pp) >= 2:
				prob_fraud = float(pp[1])
			else:
				prob_fraud = float(pp)
			is_fraud = prob_fraud >= _ACTIVE_THRESHOLD
			items.append({
				"is_fraud": bool(is_fraud),
				"fraud_probability": prob_fraud,
				"threshold_used": _ACTIVE_THRESHOLD
			})
	else:
		y_pred = ensemble.predict(X)
		for i in range(len(X)):
			pred_class = int(y_pred[i])
			items.append({
				"is_fraud": bool(pred_class == 1),
				"fraud_probability": None,
				"threshold_used": None
			})
	return {"items": items}


app = FastAPI(title="Unfraud API", version="1.0.0")
app.add_middleware(
	CORSMiddleware,
	allow_origins=["http://localhost:5173", "http://127.0.0.1:5173", "*"],
	allow_credentials=True,
	allow_methods=["*"],
	allow_headers=["*"],
)


def _load_model_and_features():
	global _MODEL, _FEATURES, _ACTIVE_THRESHOLD
	if _MODEL is None:
		if not os.path.exists(MODEL_PATH):
			raise FileNotFoundError(f"Modelo não encontrado: {MODEL_PATH}")
		_MODEL = joblib.load(MODEL_PATH)
		if os.path.exists(THRESHOLDS_PATH):
			try:
				import json
				with open(THRESHOLDS_PATH, 'r', encoding='utf-8') as f:
					data = json.load(f)
					val = data.get('threshold')
					if isinstance(val, (int, float)):
						_ACTIVE_THRESHOLD = float(val)
						print(f"[Threshold] Carregado threshold único: {_ACTIVE_THRESHOLD:.4f}")
			except Exception as e:
				print(f"[Threshold] Falha ao carregar threshold: {e}; usando 0.5")
	if _FEATURES is None:
		feat_from_model = getattr(_MODEL, "feature_names_in_", None)
		if feat_from_model is not None:
			_FEATURES = [c for c in list(feat_from_model) if c not in DROP_COLS]
		else:
			if os.path.exists(PARQUET_DATASET):
				df_cols = list(pd.read_parquet(PARQUET_DATASET).columns)
				_FEATURES = [c for c in df_cols if c not in DROP_COLS]
			elif os.path.exists(FEATHER_DATASET):
				df_cols = list(pd.read_feather(FEATHER_DATASET).columns)
				_FEATURES = [c for c in df_cols if c not in DROP_COLS]
			else:
				raise FileNotFoundError("Dataset não encontrado para inferir features")


def _load_dataset(columns: List[str]) -> pd.DataFrame:
	if os.path.exists(PARQUET_DATASET):
		df = pd.read_parquet(PARQUET_DATASET)
		use = [c for c in columns if c in df.columns] if columns else df.columns
		return df[use]
	elif os.path.exists(FEATHER_DATASET):
		df = pd.read_feather(FEATHER_DATASET)
		use = [c for c in columns if c in df.columns] if columns else df.columns
		return df[use]
	else:
		raise FileNotFoundError("Nenhum arquivo de dataset encontrado (.parquet ou .feather)")


def _compute_group_medians():
	global _CARD_MEDIANS, _TERM_MEDIANS
	if _CARD_MEDIANS or _TERM_MEDIANS:
		return
	if _FEATURES is None:
		raise RuntimeError("Features não carregadas")
	df = _load_dataset(list(set(_FEATURES + ["card_hash", "terminal_id"])))
	num_feats = [c for c in _FEATURES if c in df.columns and pd.api.types.is_numeric_dtype(df[c])]
	if "card_hash" in df.columns and num_feats:
		g = df.groupby("card_hash")[num_feats].median(numeric_only=True)
		_CARD_MEDIANS = { _normalize_id(k): {kk: float(vv) for kk, vv in row.dropna().to_dict().items()} for k, row in g.iterrows() }
	if "terminal_id" in df.columns and num_feats:
		g2 = df.groupby("terminal_id")[num_feats].median(numeric_only=True)
		_TERM_MEDIANS = { _normalize_id(k): {kk: float(vv) for kk, vv in row.dropna().to_dict().items()} for k, row in g2.iterrows() }


def _enrich_with_id_medians(items: List[Dict[str, Any]]) -> List[Dict[str, Any]]:
	if not items:
		return items
	enriched: List[Dict[str, Any]] = []
	for idx, rec in enumerate(items):
		r = dict(rec)
		ck_raw = rec.get("card_hash")
		tk_raw = rec.get("terminal_id")
		ck = _normalize_id(ck_raw)
		tk = _normalize_id(tk_raw)
		cm = _CARD_MEDIANS.get(ck) if ck is not None else None
		tm = _TERM_MEDIANS.get(tk) if tk is not None else None

		card_all = {k: float(v) for k, v in (cm or {}).items() if k in CARD_FEATURES}
		term_all = {k: float(v) for k, v in (tm or {}).items() if k in TERMINAL_FEATURES}
		card_applied: Dict[str, float] = {}
		term_applied: Dict[str, float] = {}

		if cm:
			for k, v in cm.items():
				if k in CARD_FEATURES and (k not in r or r[k] in (None, "", "NaN")):
					r[k] = v
					card_applied[k] = float(v)
		if tm:
			for k, v in tm.items():
				if k in TERMINAL_FEATURES and (k not in r or r[k] in (None, "", "NaN")):
					r[k] = v
					term_applied[k] = float(v)

		try:
			print(
				f"[Enrich] idx={idx} card_hash={ck} card_found={bool(cm)}\n"
				f"  card_all={card_all}\n  card_applied={card_applied}\n"
				f"  terminal_id={tk} term_found={bool(tm)}\n"
				f"  term_all={term_all}\n  term_applied={term_applied}",
				flush=True,
			)
		except Exception:
			pass

		enriched.append(r)
	return enriched


def _ensure_dataframe(records: List[Dict[str, Any]], feature_order: List[str]) -> pd.DataFrame:
	df = pd.DataFrame(records)
	for col in df.columns:
		df[col] = pd.to_numeric(df[col], errors="coerce")
	df = df.reindex(columns=feature_order)
	df = df.fillna(0)
	return df


def _ensure_id_sets():
	"""Populate in-memory sets of known card_hash and terminal_id from the final dataset.

	We normalize values to avoid mismatches caused by float representations (e.g. '4983922282101.0').
	"""
	global _CARD_IDS, _TERM_IDS
	if _CARD_IDS is not None and _TERM_IDS is not None:
		return
	df_ids = _load_dataset(["card_hash", "terminal_id"])

	def _normalize_series(s):
		norm = []
		for v in s.dropna().tolist():
			nv = _normalize_id(v)
			if nv is not None and nv != "":
				norm.append(nv)
		return set(norm)

	_CARD_IDS = _normalize_series(df_ids["card_hash"]) if "card_hash" in df_ids.columns else set()
	_TERM_IDS = _normalize_series(df_ids["terminal_id"]) if "terminal_id" in df_ids.columns else set()


@app.get("/health")
def health():
	return {"status": "ok"}


@app.post("/predict")
def predict_one(body: TransactionBody, request: Request):
	try:
		_load_model_and_features()
		_compute_group_medians()
		assert _FEATURES is not None
		enriched = _enrich_with_id_medians([body.features])
		X = _ensure_dataframe(enriched, _FEATURES)
		output = _predict(_MODEL, X)
		return output["items"][0]
	except Exception as e:
		traceback.print_exc()
		raise HTTPException(status_code=500, detail=str(e))


@app.post("/predict/batch")
def predict_batch(body: BatchBody, request: Request):
	try:
		if len(body.items) == 0:
			return {"items": []}
		_load_model_and_features()
		_compute_group_medians()
		assert _FEATURES is not None
		enriched = _enrich_with_id_medians(body.items)
		X = _ensure_dataframe(enriched, _FEATURES)
		output = _predict(_MODEL, X)
		return output
	except Exception as e:
		traceback.print_exc()
		raise HTTPException(status_code=500, detail=str(e))


@app.get("/ids/exists")
def ids_exists(terminal_id: Optional[str] = None, card_hash: Optional[str] = None):
	try:
		_ensure_id_sets()
		term_ok = False
		card_ok = False
		nt = _normalize_id(terminal_id) if terminal_id is not None else None
		nc = _normalize_id(card_hash) if card_hash is not None else None
		if nt is not None and _TERM_IDS is not None:
			term_ok = nt in _TERM_IDS
		if nc is not None and _CARD_IDS is not None:
			card_ok = nc in _CARD_IDS
		return {"terminal_id_exists": term_ok, "card_hash_exists": card_ok}
	except Exception as e:
		traceback.print_exc()
		raise HTTPException(status_code=500, detail=str(e))