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import os
from typing import List, Dict, Optional

import numpy as np
import pandas as pd
from fastapi import FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from fastapi.staticfiles import StaticFiles
from fastapi.responses import FileResponse
from pydantic import BaseModel, Field

from chronos import Chronos2Pipeline


# =========================
# Configuraci贸n del modelo
# =========================

MODEL_ID = os.getenv("CHRONOS_MODEL_ID", "amazon/chronos-2")
DEVICE_MAP = os.getenv("DEVICE_MAP", "cpu")  # "cpu" o "cuda"

app = FastAPI(
    title="Chronos-2 Universal Forecasting API + Excel Add-in",
    description=(
        "Servidor para pron贸sticos con Chronos-2: univariante, "
        "multivariante, covariables, escenarios, anomal铆as y backtesting. "
        "Incluye Excel Add-in v2.1.0 con archivos est谩ticos."
    ),
    version="2.1.0",
)

# Configurar CORS para Excel Add-in
app.add_middleware(
    CORSMiddleware,
    allow_origins=[
        "https://localhost:3001",
        "https://localhost:3000",
        "https://ttzzs-chronos2-excel-forecasting-api.hf.space",
        "*"  # Permitir todos los or铆genes para Office Add-ins
    ],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# Carga 煤nica del modelo al iniciar el proceso
pipeline = Chronos2Pipeline.from_pretrained(MODEL_ID, device_map=DEVICE_MAP)

# =========================
# Archivos est谩ticos para Excel Add-in
# =========================

# Montar directorios est谩ticos si existen
if os.path.exists("static"):
    app.mount("/assets", StaticFiles(directory="static/assets"), name="assets")
    app.mount("/taskpane", StaticFiles(directory="static/taskpane"), name="taskpane")
    app.mount("/commands", StaticFiles(directory="static/commands"), name="commands")
    
    # Endpoint para manifest.xml
    @app.get("/manifest.xml", response_class=FileResponse)
    async def get_manifest():
        """Devuelve el manifest.xml del Excel Add-in"""
        return FileResponse("static/manifest.xml", media_type="application/xml")
    
    @app.get("/", tags=["Info"])
    async def root_with_addon():
        """Informaci贸n del API + Add-in"""
        return {
            "name": "Chronos-2 Forecasting API",
            "version": "2.1.0",
            "model": MODEL_ID,
            "endpoints": {
                "api": [
                    "/health",
                    "/forecast_univariate",
                    "/forecast_multi_id",
                    "/forecast_with_covariates",
                    "/forecast_multivariate",
                    "/forecast_scenarios",
                    "/detect_anomalies",
                    "/backtest_simple"
                ],
                "add_in": [
                    "/manifest.xml",
                    "/taskpane/taskpane.html",
                    "/assets/icon-*.png"
                ]
            },
            "docs": "/docs",
            "excel_add_in": {
                "manifest_url": "https://ttzzs-chronos2-excel-forecasting-api.hf.space/manifest.xml",
                "version": "2.1.0",
                "features": [
                    "Univariate Forecast",
                    "Multi-Series Forecast",
                    "Forecast with Covariates",
                    "Scenario Analysis",
                    "Multivariate Forecast",
                    "Anomaly Detection",
                    "Backtest"
                ]
            }
        }
else:
    @app.get("/", tags=["Info"])
    async def root_api_only():
        """Informaci贸n del API (sin Add-in)"""
        return {
            "name": "Chronos-2 Forecasting API",
            "version": "2.1.0",
            "model": MODEL_ID,
            "docs": "/docs"
        }


# =========================
# Modelos Pydantic comunes
# =========================

class BaseForecastConfig(BaseModel):
    prediction_length: int = Field(
        7, description="Horizonte de predicci贸n (n煤mero de pasos futuros)"
    )
    quantile_levels: List[float] = Field(
        default_factory=lambda: [0.1, 0.5, 0.9],
        description="Cuantiles para el pron贸stico probabil铆stico",
    )
    start_timestamp: Optional[str] = Field(
        default=None,
        description=(
            "Fecha/hora inicial del hist贸rico (formato ISO). "
            "Si no se especifica, se usan 铆ndices enteros."
        ),
    )
    freq: str = Field(
        "D",
        description="Frecuencia temporal (p.ej. 'D' diario, 'H' horario, 'W' semanal...).",
    )


class UnivariateSeries(BaseModel):
    values: List[float]


class MultiSeriesItem(BaseModel):
    series_id: str
    values: List[float]


class CovariatePoint(BaseModel):
    """
    Punto temporal usado tanto para contexto (hist贸rico) como para covariables futuras.
    """
    timestamp: Optional[str] = None      # opcional si se usan 铆ndices enteros
    id: Optional[str] = None             # id de serie, por defecto 'series_0'
    target: Optional[float] = None       # valor de la variable objetivo (hist贸rico)
    covariates: Dict[str, float] = Field(
        default_factory=dict,
        description="Nombre -> valor de cada covariable din谩mica.",
    )


# =========================
# 1) Healthcheck
# =========================

@app.get("/health")
def health():
    """
    Devuelve informaci贸n b谩sica del estado del servidor y el modelo cargado.
    """
    return {
        "status": "ok",
        "model_id": MODEL_ID,
        "device_map": DEVICE_MAP,
    }


# =========================
# 2) Pron贸stico univariante
# =========================

class ForecastUnivariateRequest(BaseForecastConfig):
    series: UnivariateSeries


class ForecastUnivariateResponse(BaseModel):
    timestamps: List[str]
    median: List[float]
    quantiles: Dict[str, List[float]]  # "0.1" -> [..], "0.9" -> [..]


@app.post("/forecast_univariate", response_model=ForecastUnivariateResponse)
def forecast_univariate(req: ForecastUnivariateRequest):
    """
    Pron贸stico para una sola serie temporal (univariante, sin covariables).
    Pensado para uso directo desde Excel u otras herramientas sencillas.
    """
    values = req.series.values
    n = len(values)
    if n == 0:
        raise HTTPException(status_code=400, detail="La serie no puede estar vac铆a.")

    # Construimos contexto como DataFrame largo (id, timestamp, target)
    if req.start_timestamp:
        timestamps = pd.date_range(
            start=pd.to_datetime(req.start_timestamp),
            periods=n,
            freq=req.freq,
        )
    else:
        timestamps = pd.RangeIndex(start=0, stop=n, step=1)

    context_df = pd.DataFrame(
        {
            "id": ["series_0"] * n,
            "timestamp": timestamps,
            "target": values,
        }
    )

    pred_df = pipeline.predict_df(
        context_df,
        prediction_length=req.prediction_length,
        quantile_levels=req.quantile_levels,
        id_column="id",
        timestamp_column="timestamp",
        target="target",
    )

    pred_df = pred_df.sort_values("timestamp")
    timestamps_out = pred_df["timestamp"].astype(str).tolist()
    median = pred_df["predictions"].astype(float).tolist()

    quantiles_dict: Dict[str, List[float]] = {}
    for q in req.quantile_levels:
        key = f"{q:.3g}"
        if key in pred_df.columns:
            quantiles_dict[key] = pred_df[key].astype(float).tolist()

    return ForecastUnivariateResponse(
        timestamps=timestamps_out,
        median=median,
        quantiles=quantiles_dict,
    )


# =========================
# 3) Multi-serie (multi-id)
# =========================

class ForecastMultiSeriesRequest(BaseForecastConfig):
    series_list: List[MultiSeriesItem]


class SeriesForecast(BaseModel):
    series_id: str
    timestamps: List[str]
    median: List[float]
    quantiles: Dict[str, List[float]]


class ForecastMultiSeriesResponse(BaseModel):
    forecasts: List[SeriesForecast]


@app.post("/forecast_multi_id", response_model=ForecastMultiSeriesResponse)
def forecast_multi_id(req: ForecastMultiSeriesRequest):
    """
    Pron贸stico para m煤ltiples series (por ejemplo, varios SKU o tiendas).
    """
    if not req.series_list:
        raise HTTPException(status_code=400, detail="Debes enviar al menos una serie.")

    frames = []
    for item in req.series_list:
        n = len(item.values)
        if n == 0:
            continue
        if req.start_timestamp:
            timestamps = pd.date_range(
                start=pd.to_datetime(req.start_timestamp),
                periods=n,
                freq=req.freq,
            )
        else:
            timestamps = pd.RangeIndex(start=0, stop=n, step=1)

        frames.append(
            pd.DataFrame(
                {
                    "id": [item.series_id] * n,
                    "timestamp": timestamps,
                    "target": item.values,
                }
            )
        )

    if not frames:
        raise HTTPException(status_code=400, detail="Todas las series est谩n vac铆as.")

    context_df = pd.concat(frames, ignore_index=True)

    pred_df = pipeline.predict_df(
        context_df,
        prediction_length=req.prediction_length,
        quantile_levels=req.quantile_levels,
        id_column="id",
        timestamp_column="timestamp",
        target="target",
    )

    forecasts: List[SeriesForecast] = []
    for series_id, group in pred_df.groupby("id"):
        group = group.sort_values("timestamp")
        timestamps_out = group["timestamp"].astype(str).tolist()
        median = group["predictions"].astype(float).tolist()
        quantiles_dict: Dict[str, List[float]] = {}
        for q in req.quantile_levels:
            key = f"{q:.3g}"
            if key in group.columns:
                quantiles_dict[key] = group[key].astype(float).tolist()

        forecasts.append(
            SeriesForecast(
                series_id=series_id,
                timestamps=timestamps_out,
                median=median,
                quantiles=quantiles_dict,
            )
        )

    return ForecastMultiSeriesResponse(forecasts=forecasts)


# =========================
# 4) Pron贸stico con covariables
# =========================

class ForecastWithCovariatesRequest(BaseForecastConfig):
    context: List[CovariatePoint]
    future: Optional[List[CovariatePoint]] = None


class ForecastWithCovariatesResponse(BaseModel):
    # filas con todas las columnas de pred_df serializadas como string
    pred_df: List[Dict[str, str]]


@app.post("/forecast_with_covariates", response_model=ForecastWithCovariatesResponse)
def forecast_with_covariates(req: ForecastWithCovariatesRequest):
    """
    Pron贸stico con informaci贸n de covariables (promos, precio, clima...) tanto
    en el hist贸rico (context) como en futuros posibles (future).
    """
    if not req.context:
        raise HTTPException(status_code=400, detail="El contexto no puede estar vac铆o.")

    ctx_rows = []
    for p in req.context:
        if p.target is None:
            continue
        row = {
            "id": p.id or "series_0",
            "timestamp": p.timestamp,
            "target": p.target,
        }
        for k, v in p.covariates.items():
            row[k] = v
        ctx_rows.append(row)

    context_df = pd.DataFrame(ctx_rows)
    if "timestamp" not in context_df or context_df["timestamp"].isna().any():
        context_df["timestamp"] = pd.RangeIndex(start=0, stop=len(context_df), step=1)

    future_df = None
    if req.future:
        fut_rows = []
        for p in req.future:
            row = {
                "id": p.id or "series_0",
                "timestamp": p.timestamp,
            }
            for k, v in p.covariates.items():
                row[k] = v
            fut_rows.append(row)
        future_df = pd.DataFrame(fut_rows)
        if "timestamp" not in future_df or future_df["timestamp"].isna().any():
            future_df["timestamp"] = pd.RangeIndex(
                start=context_df["timestamp"].max() + 1,
                stop=context_df["timestamp"].max() + 1 + len(future_df),
                step=1,
            )

    pred_df = pipeline.predict_df(
        context_df,
        future_df=future_df,
        prediction_length=req.prediction_length,
        quantile_levels=req.quantile_levels,
        id_column="id",
        timestamp_column="timestamp",
        target="target",
    )

    pred_df = pred_df.sort_values(["id", "timestamp"])
    out_records: List[Dict[str, str]] = []
    for _, row in pred_df.iterrows():
        record = {k: str(v) for k, v in row.items()}
        out_records.append(record)

    return ForecastWithCovariatesResponse(pred_df=out_records)


# =========================
# 5) Multivariante (varios targets)
# =========================

class MultivariateContextPoint(BaseModel):
    timestamp: Optional[str] = None
    id: Optional[str] = None
    targets: Dict[str, float]            # p.ej. {"demand": 100, "returns": 5}
    covariates: Dict[str, float] = Field(default_factory=dict)


class ForecastMultivariateRequest(BaseForecastConfig):
    context: List[MultivariateContextPoint]
    target_columns: List[str]            # nombres de columnas objetivo


class ForecastMultivariateResponse(BaseModel):
    pred_df: List[Dict[str, str]]


@app.post("/forecast_multivariate", response_model=ForecastMultivariateResponse)
def forecast_multivariate(req: ForecastMultivariateRequest):
    """
    Pron贸stico multivariante: m煤ltiples columnas objetivo (p.ej. demanda y devoluciones).
    """
    if not req.context:
        raise HTTPException(status_code=400, detail="El contexto no puede estar vac铆o.")
    if not req.target_columns:
        raise HTTPException(status_code=400, detail="Debes indicar columnas objetivo.")

    rows = []
    for p in req.context:
        base = {
            "id": p.id or "series_0",
            "timestamp": p.timestamp,
        }
        for t_name, t_val in p.targets.items():
            base[t_name] = t_val
        for k, v in p.covariates.items():
            base[k] = v
        rows.append(base)

    context_df = pd.DataFrame(rows)
    if "timestamp" not in context_df or context_df["timestamp"].isna().any():
        context_df["timestamp"] = pd.RangeIndex(start=0, stop=len(context_df), step=1)

    pred_df = pipeline.predict_df(
        context_df,
        prediction_length=req.prediction_length,
        quantile_levels=req.quantile_levels,
        id_column="id",
        timestamp_column="timestamp",
        target=req.target_columns,
    )

    pred_df = pred_df.sort_values(["id", "timestamp"])
    out_records = [{k: str(v) for k, v in row.items()} for _, row in pred_df.iterrows()]
    return ForecastMultivariateResponse(pred_df=out_records)


# =========================
# 6) Escenarios (what-if)
# =========================

class ScenarioDefinition(BaseModel):
    name: str
    future_covariates: List[CovariatePoint]


class ScenarioForecast(BaseModel):
    name: str
    pred_df: List[Dict[str, str]]


class ForecastScenariosRequest(BaseForecastConfig):
    context: List[CovariatePoint]
    scenarios: List[ScenarioDefinition]


class ForecastScenariosResponse(BaseModel):
    scenarios: List[ScenarioForecast]


@app.post("/forecast_scenarios", response_model=ForecastScenariosResponse)
def forecast_scenarios(req: ForecastScenariosRequest):
    """
    Evaluaci贸n de m煤ltiples escenarios (what-if) cambiando las covariables futuras
    (por ejemplo, promo ON/OFF, diferentes precios, etc.).
    """
    if not req.context:
        raise HTTPException(status_code=400, detail="El contexto no puede estar vac铆o.")
    if not req.scenarios:
        raise HTTPException(status_code=400, detail="Debes definir al menos un escenario.")

    ctx_rows = []
    for p in req.context:
        if p.target is None:
            continue
        row = {
            "id": p.id or "series_0",
            "timestamp": p.timestamp,
            "target": p.target,
        }
        for k, v in p.covariates.items():
            row[k] = v
        ctx_rows.append(row)

    context_df = pd.DataFrame(ctx_rows)
    if "timestamp" not in context_df or context_df["timestamp"].isna().any():
        context_df["timestamp"] = pd.RangeIndex(start=0, stop=len(context_df), step=1)

    results: List[ScenarioForecast] = []

    for scen in req.scenarios:
        fut_rows = []
        for p in scen.future_covariates:
            row = {
                "id": p.id or "series_0",
                "timestamp": p.timestamp,
            }
            for k, v in p.covariates.items():
                row[k] = v
            fut_rows.append(row)
        future_df = pd.DataFrame(fut_rows)
        if "timestamp" not in future_df or future_df["timestamp"].isna().any():
            future_df["timestamp"] = pd.RangeIndex(
                start=context_df["timestamp"].max() + 1,
                stop=context_df["timestamp"].max() + 1 + len(future_df),
                step=1,
            )

        pred_df = pipeline.predict_df(
            context_df,
            future_df=future_df,
            prediction_length=req.prediction_length,
            quantile_levels=req.quantile_levels,
            id_column="id",
            timestamp_column="timestamp",
            target="target",
        )
        pred_df = pred_df.sort_values(["id", "timestamp"])
        out_records = [{k: str(v) for k, v in row.items()} for _, row in pred_df.iterrows()]

        results.append(ScenarioForecast(name=scen.name, pred_df=out_records))

    return ForecastScenariosResponse(scenarios=results)


# =========================
# 7) Detecci贸n de anomal铆as
# =========================

class AnomalyDetectionRequest(BaseModel):
    context: UnivariateSeries
    recent_observed: List[float]
    prediction_length: int = 7
    quantile_low: float = 0.05
    quantile_high: float = 0.95


class AnomalyPoint(BaseModel):
    index: int
    value: float
    predicted_median: float
    lower: float
    upper: float
    is_anomaly: bool


class AnomalyDetectionResponse(BaseModel):
    anomalies: List[AnomalyPoint]


@app.post("/detect_anomalies", response_model=AnomalyDetectionResponse)
def detect_anomalies(req: AnomalyDetectionRequest):
    """
    Marca como anomal铆as los puntos observados recientes que caen fuera del
    intervalo [quantile_low, quantile_high] del pron贸stico.
    """
    n_hist = len(req.context.values)
    if n_hist == 0:
        raise HTTPException(status_code=400, detail="La serie hist贸rica no puede estar vac铆a.")
    if len(req.recent_observed) != req.prediction_length:
        raise HTTPException(
            status_code=400,
            detail="recent_observed debe tener la misma longitud que prediction_length.",
        )

    context_df = pd.DataFrame(
        {
            "id": ["series_0"] * n_hist,
            "timestamp": pd.RangeIndex(start=0, stop=n_hist, step=1),
            "target": req.context.values,
        }
    )

    quantiles = sorted({req.quantile_low, 0.5, req.quantile_high})
    pred_df = pipeline.predict_df(
        context_df,
        prediction_length=req.prediction_length,
        quantile_levels=quantiles,
        id_column="id",
        timestamp_column="timestamp",
        target="target",
    ).sort_values("timestamp")

    q_low_col = f"{req.quantile_low:.3g}"
    q_high_col = f"{req.quantile_high:.3g}"

    anomalies: List[AnomalyPoint] = []
    for i, (obs, (_, row)) in enumerate(zip(req.recent_observed, pred_df.iterrows())):
        lower = float(row[q_low_col])
        upper = float(row[q_high_col])
        median = float(row["predictions"])
        is_anom = (obs < lower) or (obs > upper)
        anomalies.append(
            AnomalyPoint(
                index=i,
                value=obs,
                predicted_median=median,
                lower=lower,
                upper=upper,
                is_anomaly=is_anom,
            )
        )

    return AnomalyDetectionResponse(anomalies=anomalies)


# =========================
# 8) Backtest simple
# =========================

class BacktestRequest(BaseModel):
    series: UnivariateSeries
    prediction_length: int = 7
    test_length: int = 28


class BacktestMetrics(BaseModel):
    mae: float
    mape: float
    wql: float  # Weighted Quantile Loss aproximada para el cuantil 0.5


class BacktestResponse(BaseModel):
    metrics: BacktestMetrics
    forecast_median: List[float]
    forecast_timestamps: List[str]
    actuals: List[float]


@app.post("/backtest_simple", response_model=BacktestResponse)
def backtest_simple(req: BacktestRequest):
    """
    Backtest sencillo: separamos un tramo final de la serie como test, pronosticamos
    ese tramo y calculamos m茅tricas MAE / MAPE / WQL.
    """
    values = np.array(req.series.values, dtype=float)
    n = len(values)
    if n <= req.test_length:
        raise HTTPException(
            status_code=400,
            detail="La serie debe ser m谩s larga que test_length.",
        )

    train = values[: n - req.test_length]
    test = values[n - req.test_length :]

    context_df = pd.DataFrame(
        {
            "id": ["series_0"] * len(train),
            "timestamp": pd.RangeIndex(start=0, stop=len(train), step=1),
            "target": train.tolist(),
        }
    )

    pred_df = pipeline.predict_df(
        context_df,
        prediction_length=req.test_length,
        quantile_levels=[0.5],
        id_column="id",
        timestamp_column="timestamp",
        target="target",
    ).sort_values("timestamp")

    forecast = pred_df["predictions"].to_numpy(dtype=float)
    timestamps = pred_df["timestamp"].astype(str).tolist()

    mae = float(np.mean(np.abs(test - forecast)))
    eps = 1e-8
    mape = float(np.mean(np.abs((test - forecast) / (test + eps)))) * 100.0
    tau = 0.5
    diff = test - forecast
    wql = float(np.mean(np.maximum(tau * diff, (tau - 1) * diff)))

    metrics = BacktestMetrics(mae=mae, mape=mape, wql=wql)

    return BacktestResponse(
        metrics=metrics,
        forecast_median=forecast.tolist(),
        forecast_timestamps=timestamps,
        actuals=test.tolist(),
    )