# -*- coding: utf-8 -*-
#
# **DEPRECATED**
#
# These exporters have been deprecated in favor
# of the DatasetExport resource.
#



from six.moves.urllib.parse import urlparse
from six.moves.urllib.parse import unquote

import datetime
import json
import os
import sys
import time
import six
import pyprind

from .utils.humanize import naturalsize

try:
    import unicodecsv as csv
except ImportError:
    import csv

try:
    import xlsxwriter
except ImportError:
    xlsxwriter = None


class QueryExporters(object):
    """Maintains a list of available exporters."""
    EXPORT_WARN = 5000
    PAGE_SIZE = 500

    registry = {}

    def register(self, klass):
        self.registry[klass.name.lower()] = klass

    def export(self, exporter, query, *args, **kwargs):
        exporter = exporter.lower()
        force = kwargs.pop('force', False)

        # Set the page size
        page_size = kwargs.get('page_size', self.PAGE_SIZE)

        if exporter not in self.registry:
            raise Exception('Invalid exporter: {0}. Available exporters: {1}'
                            .format(exporter, ', '.join(list(self.registry.keys()))))

        nrecords = len(query)
        if nrecords == 0:
            raise Exception('There are no results to export.')
        elif nrecords > self.EXPORT_WARN and not force:
            print('To export {0} records, use `force=True`.'
                  .format(nrecords))
            return

        # Increase the efficiency of the export.
        query._page_size = page_size
        # Enable progress by default on large exports, but allow toggle.
        show_progress = kwargs.pop('show_progress',
                                   nrecords > self.EXPORT_WARN)
        return self.registry[exporter](query, show_progress=show_progress)\
            .export(*args, **kwargs)


class JSONExporter(object):
    """
    Exports dataset query to JSON (specifically JSONL),
    one JSON record per line.
    """
    name = 'json'

    def __init__(self, query, *args, **kwargs):
        self.query = query
        self.show_progress = kwargs.get('show_progress', False)
        self.exclude_fields = kwargs.get('exclude_fields', ['_id', '_commit'])

    def export(self, filename=None, **kwargs):
        if not filename:
            raise Exception(
                'The "filename" parameter is required to export.')

        result_count = len(self.query)
        if result_count <= 0:
            raise AttributeError('No results found in query!')

        filename = os.path.expanduser(filename)
        if sys.version_info >= (3, 0, 0):
            f = open(filename, 'w', newline='')
        else:
            f = open(filename, 'wb')

        if self.show_progress:
            progress_bar = pyprind.ProgPercent(
                result_count,
                title='JSON Export',
                track_time=False)

        try:
            for ind, record in enumerate(self.query):
                for field in self.exclude_fields:
                    record.pop(field, None)
                f.write(json.dumps(record) + '\n')
                if self.show_progress:
                    progress_bar.update()
        finally:
            f.close()

        print('Export complete!')


class CSVExporter(object):
    """
    This class includes helper functions to export
    a SolveBio Query object to a CSV file.
    """
    name = 'csv'

    collection = None

    SEP_CHAR = str(',')
    KEY_SEP = str('.')

    def __init__(self, query, *args, **kwargs):
        self.query = query
        self.show_progress = kwargs.get('show_progress', False)
        self.exclude_fields = kwargs.get('exclude_fields', ['_id'])
        self.rows = []
        self.fields = set([])
        self.current_row = {}

    def export(self, filename=None, **kwargs):
        if not filename:
            raise Exception(
                'The "filename" parameter is required to export.')

        filename = os.path.expanduser(filename)
        title = 'Exporting query to: {0}'.format(filename)

        result_count = len(self.query)
        if result_count <= 0:
            raise AttributeError('No results found in query!')

        if self.show_progress:
            progress_bar = pyprind.ProgPercent(
                result_count,
                title=title,
                track_time=False)
        else:
            print(title)

        for record in self.query:
            self.current_row = {}
            self.process_record(record)
            self.rows.append(self.current_row)
            if self.show_progress:
                progress_bar.update()

        self.write(filename=filename)
        print('Export complete!')

    def process_record(self, record, root_key=''):
        """Process a row of json data
        """
        if root_key != '':
            root_key += '.'

        # Tree traversal
        for key, value in six.iteritems(record):
            # Do not process excluded fields
            if key not in self.exclude_fields:
                field = root_key + key
                # If the value is an object, process it recursively
                if isinstance(value, dict):
                    self.process_record(value, field)
                # If the value is a list, parse each item
                elif isinstance(value, list):
                    for index, item in enumerate(value):
                        field_name = field + self.KEY_SEP + str(index)
                        if isinstance(item, dict):
                            self.process_record(item, field_name)
                        else:
                            self.fields.add(field_name)
                            self.current_row[field_name] = \
                                self.make_string(item)
                # If we reached a leaf, add field and value
                else:
                    self.fields.add(field)
                    self.current_row[field] = self.make_string(value)

    @staticmethod
    def make_string(value):
        try:
            return str(value)
        except UnicodeEncodeError:
            return ''.join(
                [s.encode('ascii', 'backslashreplace') for s in value]
            )

    def write(self, filename):
        if sys.version_info >= (3, 0, 0):
            f = open(filename, 'w', newline='')
        else:
            f = open(filename, 'wb')

        fieldnames = sorted(list(self.fields))
        try:
            writer = csv.DictWriter(f, fieldnames=fieldnames,
                                    delimiter=self.SEP_CHAR)
            # writer.writeheader() is new in 2.7
            # The following is used for 2.6 compat:
            writer.writerow(dict(list(zip(fieldnames, fieldnames))))
            writer.writerows(self.rows)
        finally:
            f.close()


class XLSXExporter(CSVExporter):
    """Uses XlsxWriter to export a valid XLS."""

    name = 'excel'

    def __init__(self, query, *args, **kwargs):
        if not xlsxwriter:
            raise Exception(
                'The XLSX exporter requires the xlsxwriter Python module. '
                'Run `pip install XlsxWriter` and reload SolveBio.')

        super(XLSXExporter, self).__init__(query, *args, **kwargs)

    def write(self, filename):
        workbook = xlsxwriter.Workbook(filename)
        worksheet = workbook.add_worksheet()
        formats = {
            'text': workbook.add_format({'text_wrap': True}),
            'string': workbook.add_format(),
            'header': workbook.add_format({'bold': True}),
            'integer': workbook.add_format(),
            'double': workbook.add_format(),
            'long': workbook.add_format(),
            'float': workbook.add_format(),
        }
        formats['date'] = formats['string']
        formats['boolean'] = formats['string']
        formats['text'].set_align('top')
        formats['nested'] = formats['text']
        formats['object'] = formats['text']

        fieldnames = sorted(list(self.fields))
        index_field_map = dict((field, index)
                               for index, field in enumerate(fieldnames))

        row = 0
        # Write the header
        for index, field in enumerate(fieldnames):
            worksheet.write(row, index, field, formats['header'])

        # Write the rows
        for record in self.rows:
            row += 1
            for key, value in six.iteritems(record):
                worksheet.write(row, index_field_map[key],
                                value, formats['string'])

        workbook.close()


exporters = QueryExporters()
exporters.register(JSONExporter)
exporters.register(CSVExporter)
exporters.register(XLSXExporter)


# Bulk Dataset Exports

class DatasetExportFile(object):
    """PyCurl-wrapper for downloading files from a bulk Dataset export.
    """
    progress_template = ('%(percent)6d%% %(downloaded)12s %(speed)15s '
                         '%(eta)18s ETA' + ' ' * 4)
    eta_limit = 60 * 60 * 24 * 30
    max_retries = 5

    def __init__(self, url, path=None, show_progress=True):
        self.url = url
        self.show_progress = show_progress
        self.start_time = None
        self.content_length = 0
        self.downloaded = 0

        self.path = os.path.abspath(os.path.expanduser(path))
        self.parsed_url = urlparse(url)
        self.file_name = unquote(os.path.basename(self.parsed_url.path))

        # Get output path from URL if a dir is provided.
        if os.path.isdir(self.path):
            self.path = os.path.join(self.path, self.file_name)

        self._last_time = 0.0
        self._rst_retries = 0

    @property
    def is_finished(self):
        if os.path.exists(self.path):
            return self.content_length == os.path.getsize(self.path)

    def download(self):
        # On some machines, pycurl fails to import. Make sure this error
        # only gets raised when export is used, rather than on startup.
        import pycurl

        curl = pycurl.Curl()

        while not self.is_finished:
            try:
                if os.path.exists(self.path):
                    print("Resuming download for {0}".format(self.path))
                    mode = 'ab'
                    self.downloaded = os.path.getsize(self.path)
                    curl.setopt(pycurl.RESUME_FROM, self.downloaded)
                else:
                    mode = 'wb'

                with open(self.path, mode) as f:
                    curl.setopt(curl.URL, self.url)
                    curl.setopt(curl.WRITEDATA, f)
                    curl.setopt(curl.NOPROGRESS, 0)
                    curl.setopt(pycurl.FOLLOWLOCATION, 1)
                    curl.setopt(curl.PROGRESSFUNCTION, self.progress)
                    curl.perform()
            except pycurl.error as e:
                # transfer closed with n bytes remaining to read
                if e.args[0] == pycurl.E_PARTIAL_FILE:
                    pass
                # HTTP server doesn't seem to support byte ranges.
                # Cannot resume.
                elif e.args[0] == pycurl.E_HTTP_RANGE_ERROR:
                    break
                # Recv failure: Connection reset by peer
                elif e.args[0] == pycurl.E_RECV_ERROR:
                    if self._rst_retries < self.max_retries:
                        pass
                else:
                    raise e
                self._rst_retries += 1

        sys.stderr.write('\n')
        sys.stderr.flush()

    def progress(self, download_t, download_d, upload_t, upload_d):
        self.content_length = self.downloaded + int(download_t)

        if not self.show_progress or int(download_t) == 0:
            return
        elif self.start_time is None:
            self.start_time = time.time()

        duration = time.time() - self.start_time + 1
        speed = download_d / duration
        speed_s = naturalsize(speed, binary=True)
        speed_s += '/s'

        if speed == 0.0:
            eta = self.eta_limit
        else:
            eta = int((download_t - download_d) / speed)

        if eta < self.eta_limit:
            eta_s = str(datetime.timedelta(seconds=eta))
        else:
            eta_s = 'n/a'

        downloaded = self.downloaded + download_d
        downloaded_s = naturalsize(downloaded, binary=True)

        percent = int(downloaded / self.content_length * 100)
        params = {
            'downloaded': downloaded_s,
            'percent': percent,
            'speed': speed_s,
            'eta': eta_s,
        }

        if sys.stderr.isatty():
            p = (self.progress_template + '\r') % params
        else:
            current_time = time.time()
            if self._last_time == 0.0:
                self._last_time = current_time
            else:
                interval = current_time - self._last_time
                if interval < 0.5:
                    return
                self._last_time = current_time
            p = (self.progress_template + '\n') % params

        sys.stderr.write(p)
        sys.stderr.flush()
