import os

import numpy  as np
import pandas as pd
from pandas_datareader.data import DataReader
from pandas_datareader._utils import RemoteDataError
import requests

from zipline.utils.cli import maybe_show_progress


def _cachpath(symbol, type_):
    return '-'.join((symbol.replace(os.path.sep, '_'), type_))


def google_equities(symbols, start=None, end=None):
    symbols = tuple(symbols)

    def ingest(environ,
               asset_db_writer,
               minute_bar_writer,  # unused
               daily_bar_writer,
               adjustment_writer,
               calendar,
               start_session,
               end_session,
               cache,
               show_progress,
               output_dir,
               start=start,
               end=end):
        if start is None:
            start = start_session
        if end is None:
            end = None

        metadata = pd.DataFrame(np.empty(len(symbols), dtype=[
            ('start_date', 'datetime64[ns]'),
            ('end_date', 'datetime64[ns]'),
            ('auto_close_date', 'datetime64[ns]'),
            ('symbol', 'object'),
        ]))

        def _pricing_iter():
            sid = 0
            with maybe_show_progress(
                    symbols,
                    show_progress,
                    label='Downloading Google pricing data: ') as it, \
                    requests.Session() as session:
                for symbol in it:
                    path = _cachpath(symbol, 'ohlcv')
                    try:
                        df = cache[path]
                    except KeyError:
                        df = cache[path] = DataReader(
                            symbol,
                            'google',
                            start,
                            end,
                            session=session,
                        ).sort_index()

                    # the start date is the date of the first trade and
                    # the end date is the date of the last trade
                    start_date = df.index[0]
                    end_date = df.index[-1]
                    # The auto_close date is the day after the last trade.
                    ac_date = end_date + pd.Timedelta(days=1)
                    metadata.iloc[sid] = start_date, end_date, ac_date, symbol

                    df.rename(
                        columns={
                            'Open': 'open',
                            'High': 'high',
                            'Low': 'low',
                            'Close': 'close',
                            'Volume': 'volume',
                        },
                        inplace=True,
                    )
                    yield sid, df
                    sid += 1

        daily_bar_writer.write(_pricing_iter(), show_progress=show_progress)

        symbol_map = pd.Series(metadata.symbol.index, metadata.symbol)

        metadata['exchange'] = "GOOGLE"
        asset_db_writer.write(equities=metadata)

        adjustments = []
        with maybe_show_progress(
                symbols,
                show_progress,
                label='Downloading Yahoo adjustment data: ') as it, \
                requests.Session() as session:
            for symbol in it:
                path = _cachpath(symbol, 'adjustment')
                sid = symbol_map[symbol]
                try:
                    df = cache[path]
                except KeyError:
                    try:
                        df = cache[path] = DataReader(
                            symbol,
                            'yahoo-actions',
                            metadata.ix[sid].start_date,
                            metadata.ix[sid].end_date,
                            session=session,
                        ).sort_index()
                    except RemoteDataError:
                        print("No data returned from Yahoo for %s" % symbol)
                        df = pd.DataFrame(columns=['value', 'action'])

                df['sid'] = sid
                adjustments.append(df)

        adj_df = pd.concat(adjustments)
        adj_df.index.name = 'date'
        adj_df.reset_index(inplace=True)

        splits = adj_df[adj_df.action == 'SPLIT']
        splits = splits.rename(
            columns={'value': 'ratio', 'date': 'effective_date'},
        )
        splits.drop('action', axis=1, inplace=True)

        dividends = adj_df[adj_df.action == 'DIVIDEND']
        dividends = dividends.rename(
            columns={'value': 'amount', 'date': 'ex_date'},
        )
        dividends.drop('action', axis=1, inplace=True)
        # we do not have this data in the yahoo dataset
        dividends['record_date'] = pd.NaT
        dividends['declared_date'] = pd.NaT
        dividends['pay_date'] = pd.NaT

        adjustment_writer.write(splits=splits, dividends=dividends)

    return ingest