# Copyright 2016 Egor Tensin <Egor.Tensin@gmail.com>
# This file is licensed under the terms of the MIT License.
# See LICENSE.txt for details.

import argparse
import csv
from collections import OrderedDict
from datetime import datetime, timedelta, timezone
from enum import Enum
import json
import sys

import matplotlib.pyplot as plt
import numpy as np

from vk.tracking import OnlineStreakEnumerator
from vk.tracking.db import Format as DatabaseFormat
from vk.user import UserField

class Grouping(Enum):
    USER = 'user'
    DATE = 'date'
    WEEKDAY = 'weekday'
    HOUR = 'hour'

    def enum_durations(self, db_reader, date_from=None, date_to=None):
        if self is Grouping.USER:
            return OnlineStreakEnumerator(date_from, date_to).group_by_user(db_reader)
        elif self is Grouping.DATE:
            return OnlineStreakEnumerator(date_from, date_to).group_by_date(db_reader)
        elif self is Grouping.WEEKDAY:
            return OnlineStreakEnumerator(date_from, date_to).group_by_weekday(db_reader)
        elif self is Grouping.HOUR:
            return OnlineStreakEnumerator(date_from, date_to).group_by_hour(db_reader)
        else:
            raise NotImplementedError('unsupported grouping: ' + str(self))

    def __str__(self):
        return self.value

_OUTPUT_USER_FIELDS = (
    UserField.UID,
    UserField.FIRST_NAME,
    UserField.LAST_NAME,
    UserField.SCREEN_NAME,
)

class OutputConverterCSV:
    @staticmethod
    def convert_user(user):
        return [user[field] for field in _OUTPUT_USER_FIELDS]

    @staticmethod
    def convert_date(date):
        return [str(date)]

    @staticmethod
    def convert_weekday(weekday):
        return [str(weekday)]

    @staticmethod
    def convert_hour(hour):
        return [str(timedelta(hours=hour))]

class OutputWriterCSV:
    def __init__(self, fd=sys.stdout):
        self._writer = csv.writer(fd, lineterminator='\n')

    _CONVERT_KEY = {
        Grouping.USER: OutputConverterCSV.convert_user,
        Grouping.DATE: OutputConverterCSV.convert_date,
        Grouping.WEEKDAY: OutputConverterCSV.convert_weekday,
        Grouping.HOUR: OutputConverterCSV.convert_hour,
    }

    @staticmethod
    def _key_to_row(grouping, key):
        if grouping not in OutputWriterCSV._CONVERT_KEY:
            raise NotImplementedError('unsupported grouping: ' + str(grouping))
        return OutputWriterCSV._CONVERT_KEY[grouping](key)

    def process_database(self, grouping, db_reader, date_from=None, date_to=None):
        for key, duration in grouping.enum_durations(db_reader, date_from, date_to).items():
            row = self._key_to_row(grouping, key)
            row.append(str(duration))
            self._write_row(row)

    def _write_row(self, row):
        self._writer.writerow(row)

class OutputConverterJSON:
    _DATE_FIELD = 'date'
    _WEEKDAY_FIELD = 'weekday'
    _HOUR_FIELD = 'hour'

    @staticmethod
    def convert_user(user):
        obj = OrderedDict()
        for field in _OUTPUT_USER_FIELDS:
            obj[str(field)] = user[field]
        return obj

    @staticmethod
    def convert_date(date):
        obj = OrderedDict()
        obj[OutputConverterJSON._DATE_FIELD] = str(date)
        return obj

    @staticmethod
    def convert_weekday(weekday):
        obj = OrderedDict()
        obj[OutputConverterJSON._WEEKDAY_FIELD] = str(weekday)
        return obj

    @staticmethod
    def convert_hour(hour):
        obj = OrderedDict()
        obj[OutputConverterJSON._HOUR_FIELD] = str(timedelta(hours=hour))
        return obj

class OutputWriterJSON:
    def __init__(self, fd=sys.stdout):
        self._fd = fd

    _DURATION_FIELD = 'duration'

    _CONVERT_KEY = {
        Grouping.USER: OutputConverterJSON.convert_user,
        Grouping.DATE: OutputConverterJSON.convert_date,
        Grouping.WEEKDAY: OutputConverterJSON.convert_weekday,
        Grouping.HOUR: OutputConverterJSON.convert_hour,
    }

    @staticmethod
    def _key_to_object(grouping, key):
        if not grouping in OutputWriterJSON._CONVERT_KEY:
            raise NotImplementedError('unsupported grouping: ' + str(grouping))
        return OutputWriterJSON._CONVERT_KEY[grouping](key)

    def _write(self, x):
        self._fd.write(json.dumps(x, indent=3, ensure_ascii=False))
        self._fd.write('\n')

    def process_database(self, grouping, db_reader, date_from=None, date_to=None):
        arr = []
        for key, duration in grouping.enum_durations(db_reader, date_from, date_to).items():
            obj = self._key_to_object(grouping, key)
            obj[self._DURATION_FIELD] = str(duration)
            arr.append(obj)
        self._write(arr)

class BarChartBuilder:
    _BAR_HEIGHT = 1.

    def __init__(self):
        self._fig, self._ax = plt.subplots()

    def set_title(self, title):
        self._ax.set_title(title)

    def _get_bar_axis(self):
        return self._ax.get_yaxis()

    def _get_value_axis(self):
        return self._ax.get_xaxis()

    def set_bar_axis_limits(self, start=None, end=None):
        self._ax.set_ylim(bottom=start, top=end)

    def set_value_axis_limits(self, start=None, end=None):
        self._ax.set_xlim(left=start, right=end)

    def set_value_grid(self):
        self._get_value_axis().grid()

    def get_bar_labels(self):
        return self._get_bar_axis().get_ticklabels()

    def get_value_labels(self):
        return self._get_value_axis().get_ticklabels()

    def set_value_label_formatter(self, fn):
        from matplotlib.ticker import FuncFormatter
        self._get_value_axis().set_major_formatter(FuncFormatter(fn))

    def set_integer_values_only(self):
        from matplotlib.ticker import MaxNLocator
        self._get_value_axis().set_major_locator(MaxNLocator(integer=True))

    @staticmethod
    def set_property(*args, **kwargs):
        plt.setp(*args, **kwargs)

    def _set_size(self, inches, dim=0):
        fig_size = self._fig.get_size_inches()
        assert len(fig_size) == 2
        fig_size[dim] = inches
        self._fig.set_size_inches(fig_size, forward=True)

    def set_width(self, inches):
        self._set_size(inches)

    def set_height(self, inches):
        self._set_size(inches, dim=1)

    def plot_bars(self, bar_labels, values, datetime_ticks=False):
        numof_bars = len(bar_labels)

        if not numof_bars:
            self.set_height(1)
            self._get_bar_axis().set_tick_params(labelleft=False)
            return []

        self.set_height(numof_bars / 2 if datetime_ticks else numof_bars)

        bar_offsets = np.arange(numof_bars) * 2 * self._BAR_HEIGHT + self._BAR_HEIGHT
        bar_axis_min, bar_axis_max = 0, 2 * self._BAR_HEIGHT * numof_bars

        if datetime_ticks:
            self._get_bar_axis().set_ticks(bar_offsets - self._BAR_HEIGHT)
        else:
            self._get_bar_axis().set_ticks(bar_offsets)

        self._get_bar_axis().set_ticklabels(bar_labels)
        self.set_bar_axis_limits(bar_axis_min, bar_axis_max)

        return self._ax.barh(bar_offsets, values, align='center', height=self._BAR_HEIGHT)

    @staticmethod
    def show():
        plt.show()

    def save(self, path):
        self._fig.savefig(path, bbox_inches='tight')

class OutputConverterPlot:
    @staticmethod
    def convert_user(user):
        return '{}\n{}'.format(user.get_first_name(), user.get_last_name())

    @staticmethod
    def convert_date(date):
        return str(date)

    @staticmethod
    def convert_weekday(weekday):
        return str(weekday)

    @staticmethod
    def convert_hour(hour):
        return '{}:00'.format(hour)

class OutputWriterPlot:
    def __init__(self, fd=sys.stdout):
        self._fd = fd

    TITLE = 'How much time people spend online'

    _FORMAT_KEY = {
        Grouping.USER: OutputConverterPlot.convert_user,
        Grouping.DATE: OutputConverterPlot.convert_date,
        Grouping.WEEKDAY: OutputConverterPlot.convert_weekday,
        Grouping.HOUR: OutputConverterPlot.convert_hour,
    }

    @staticmethod
    def _format_key(grouping, key):
        if grouping not in OutputWriterPlot._FORMAT_KEY:
            raise NotImplementedError('unsupported grouping: ' + str(grouping))
        return OutputWriterPlot._FORMAT_KEY[grouping](key)

    @staticmethod
    def _format_duration(seconds, _):
        return str(timedelta(seconds=seconds))

    @staticmethod
    def _duration_to_seconds(td):
        return td.total_seconds()

    @staticmethod
    def _extract_labels(grouping, durations):
        return tuple(map(lambda key: OutputWriterPlot._format_key(grouping, key), durations.keys()))

    @staticmethod
    def _extract_values(durations):
        return tuple(map(OutputWriterPlot._duration_to_seconds, durations.values()))

    def process_database(self, grouping, db_reader, date_from=None, date_to=None):
        durations = grouping.enum_durations(db_reader, date_from, date_to)

        bar_chart = BarChartBuilder()

        bar_chart.set_title(OutputWriterPlot.TITLE)
        bar_chart.set_value_grid()

        bar_chart.set_integer_values_only()
        bar_chart.set_property(bar_chart.get_value_labels(),
                               fontsize='small', rotation=30)
        bar_chart.set_value_label_formatter(self._format_duration)

        labels = self._extract_labels(grouping, durations)
        durations = self._extract_values(durations)

        if not labels or not max(durations):
            bar_chart.set_value_axis_limits(0)

        bars = bar_chart.plot_bars(labels, durations, grouping is Grouping.HOUR)
        bar_chart.set_property(bars, alpha=.33)

        if self._fd is sys.stdout:
            bar_chart.show()
        else:
            bar_chart.save(self._fd)

class OutputFormat(Enum):
    CSV = 'csv'
    JSON = 'json'
    PLOT = 'plot'

    def create_writer(self, fd):
        if self is OutputFormat.CSV:
            return OutputWriterCSV(fd)
        elif self is OutputFormat.JSON:
            return OutputWriterJSON(fd)
        elif self is OutputFormat.PLOT:
            return OutputWriterPlot(fd)
        else:
            raise NotImplementedError('unsupported output format: ' + str(self))

    def __str__(self):
        return self.value

def _parse_grouping(s):
    try:
        return Grouping(s)
    except ValueError:
        raise argparse.ArgumentTypeError('invalid grouping: ' + str(s))

def _parse_database_format(s):
    try:
        return DatabaseFormat(s)
    except ValueError:
        raise argparse.ArgumentTypeError('invalid database format: ' + str(s))

def _parse_output_format(s):
    try:
        return OutputFormat(s)
    except ValueError:
        raise argparse.ArgumentTypeError('invalid output format: ' + str(s))

_DATE_RANGE_LIMIT_FORMAT = '%Y-%m-%dT%H:%M:%SZ'

def _parse_date_range_limit(s):
    try:
        dt = datetime.strptime(s, _DATE_RANGE_LIMIT_FORMAT)
        return dt.replace(tzinfo=timezone.utc)
    except ValueError:
        msg = 'invalid date range limit (must be in the \'{}\' format): {}'
        raise argparse.ArgumentTypeError(
            msg.format(_DATE_RANGE_LIMIT_FORMAT, s))

def _parse_args(args=sys.argv):
    parser = argparse.ArgumentParser(
        description='View/visualize the amount of time people spend online.')

    parser.add_argument('db_fd', metavar='input',
                        type=argparse.FileType('r', encoding='utf-8'),
                        help='database path')
    parser.add_argument('fd', metavar='output', nargs='?',
                        type=argparse.FileType('w', encoding='utf-8'),
                        default=sys.stdout,
                        help='output path (standard output by default)')
    parser.add_argument('--grouping',
                        type=_parse_grouping, default=Grouping.USER,
                        choices=tuple(grouping for grouping in Grouping),
                        help='set grouping')
    parser.add_argument('--input-format', dest='db_fmt',
                        type=_parse_database_format,
                        default=DatabaseFormat.CSV,
                        choices=tuple(fmt for fmt in DatabaseFormat),
                        help='specify database format')
    parser.add_argument('--output-format', dest='fmt',
                        type=_parse_output_format, default=OutputFormat.CSV,
                        choices=tuple(fmt for fmt in OutputFormat),
                        help='specify output format')
    parser.add_argument('--from', dest='date_from',
                        type=_parse_date_range_limit, default=None,
                        help='set the date to process database records from')
    parser.add_argument('--to', dest='date_to',
                        type=_parse_date_range_limit, default=None,
                        help='set the date to process database record to')

    return parser.parse_args(args[1:])

def write_online_duration(db_fd, fd=sys.stdout,
                          db_fmt=DatabaseFormat.CSV,
                          fmt=OutputFormat.CSV,
                          grouping=Grouping.USER,
                          date_from=None, date_to=None):

    if date_from is not None and date_to is not None:
        if date_from > date_to:
            date_from, date_to = date_to, date_from

    with db_fmt.create_reader(db_fd) as db_reader:
        output_writer = fmt.create_writer(fd)
        output_writer.process_database(grouping, db_reader,
                                       date_from=date_from,
                                       date_to=date_to)

def main(args=sys.argv):
    args = _parse_args(args)
    write_online_duration(**vars(args))

if __name__ == '__main__':
    main()