from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
from vnstock import Vnstock
from datetime import datetime, timedelta
import pandas as pd
import numpy as np

vn = Vnstock()
app = FastAPI(title="mFund VNStock API", version="1.0")

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

# ============================
# Chỉ báo kỹ thuật
# ============================
def calc_RSI(series, period=14):
    delta = series.diff()
    gain = delta.clip(lower=0)
    loss = -delta.clip(upper=0)
    avg_gain = gain.rolling(period).mean()
    avg_loss = loss.rolling(period).mean()
    RS = avg_gain / avg_loss
    return 100 - (100 / (1 + RS))

def calc_MACD(series, fast=12, slow=26, signal=9):
    ema_fast = series.ewm(span=fast, adjust=False).mean()
    ema_slow = series.ewm(span=slow, adjust=False).mean()
    macd = ema_fast - ema_slow
    signal_line = macd.ewm(span=signal, adjust=False).mean()
    return macd, signal_line, macd - signal_line

def calc_bollinger(series, window=20, num_std=2):
    sma = series.rolling(window).mean()
    std = series.rolling(window).std()
    return sma, sma + num_std * std, sma - num_std * std

# ============================
# 1) GET /stock/history
# ============================
@app.get("/stock/history")
def get_history(symbol: str, start: str, end: str):
    try:
        if end < start:
            return {"error": "end must be >= start"}

        stock = vn.stock(symbol=symbol)
        if stock is None:
            return {"error": "invalid symbol"}

        df = stock.quote.history(start=start, end=end, interval="1D")

        if df is None or df.empty:
            return {"error": "no data"}

        if "time" in df.columns:
            df = df.rename(columns={"time": "Date"}).set_index("Date")

        if "close" in df.columns:
            df = df.rename(columns={"close": "Close"})

        df.index = df.index.astype(str)
        return {"symbol": symbol, "data": df.to_dict()}
    except Exception as e:
        return {"error": str(e)}

# ============================
# 2) GET /stock/ta
# ============================
@app.get("/stock/ta")
def get_ta(symbol: str, start: str, end: str):
    try:
        if end < start:
            return {"error": "end must be >= start"}

        stock = vn.stock(symbol=symbol)
        if stock is None:
            return {"error": "invalid symbol"}

        df = stock.quote.history(start=start, end=end, interval="1D")

        if df is None or df.empty:
            return {"error": "no data"}

        df["RSI"] = calc_RSI(df["close"])
        df["MACD"], df["MACD_signal"], df["MACD_hist"] = calc_MACD(df["close"])
        df["BB_MID"], df["BB_UPPER"], df["BB_LOWER"] = calc_bollinger(df["close"])

        df = df.fillna(None)
        df.index = df.index.astype(str)
        return {"symbol": symbol, "indicators": df.to_dict()}
    except Exception as e:
        return {"error": str(e)}

@app.get("/")
def root():
    return {
        "message": "mFund VNStock FastAPI is running",
        "endpoints": [
            "/stock/history?symbol=FPT&start=2023-01-01&end=2023-12-31",
            "/stock/ta?symbol=HPG&start=2023-01-01&end=2023-12-31",
        ],
    }