import time
import logging
from pathlib import Path
from configparser import ConfigParser
from sehistory.influx import InfluxDBWrapper, abs_range, round_range, Table

ETERNITY = 1e10


def fmtime(t):
    if t is None:
        return ' ' * 19
    if t >= ETERNITY:
        return '-' * 19
    return time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(int(t)))


def sameday(ts1, ts2):
    return time.localtime(ts1)[:3] == time.localtime(ts2)[:3]


def summarize_tags(curves, remove_multiple=False):
    """summarize tags

    :param curves: list of curves (type Table)
    :param remove_multiple: True: remove non-unique values
    :return: dict <key> of comma separated values
    """
    result = {}
    for curve in curves:
        for k, v in curve.tags.items():
            result.setdefault(k, set()).add(str(v))
    if remove_multiple:
        return {k: ','.join(v) for k, v in result.items() if len(v) == 1}
    return {k: ','.join(v) for k, v in result.items()}


class SEHistory(InfluxDBWrapper):
    def __init__(self, dbname=None, instrument=None, access='readonly'):
        self.instrument = instrument
        parser = ConfigParser()
        parser.optionxform = str
        parser.read([Path('~/.config/sehistory').expanduser()])
        section = parser[dbname] if dbname else parser[parser.sections()[0]]
        self.has_local = parser.has_section('local')
        self.instrument_by_stream = {}
        super().__init__(*(section[k] for k in ('uri', 'token', 'org', 'bucket')), access=access)

    def curves(self, start=None, stop=None, measurement=('*.value', '*.target'), field='float',
               interval=None, add_prev=3600, add_end=False, merge=None, pivot=False, **kwds):
        """get curves

        :param start: start time (default: since ever)
        :param stop: end time (default: eternity = 1 year in the future)
        :param measurement: '<module>.<parameter>' (default: ['*.value', '*.target'])
        :param field: default 'float' (only numeric curves)
        :param interval: if given, the result is binned
        :param add_prev: amount of time to look back for the last previous point (default: 1 hr)
        :param add_end: whether to add endpoint at stop time (default: False)
        :param merge: None: no merge happens, else curves with the same final key are merged. 2 cases:
            one key (str): the name of final key. result will be a dict of <str> of <Table>
            a tuple of keys: the names of the final key elements. result: dict of <tuple> of Table
        :param pivot: sort values in to columns of one big table
        :param kwds: further selection criteria
        :return: a dict <key or tuple of key values> of <Table> or <Single>

        where <Table> is a list of tuples with some meta info (table.tags, table.column_names)
        and <Single> is a list (a single row of a table) with the same meta info

        when _field='float' (the default), the returned values are either a floats or None
        """
        tags = {k: v for k, v in (('_measurement', measurement), ('_field', field)) if v is not None}
        tags.update(kwds)
        start, stop = abs_range(start, stop)
        rstart, rstop = round_range(start, stop, interval)
        if rstart < rstop:
            result = self.query(rstart, rstop, interval, columns=None, **tags)
            # result = self.query(rstart, rstop, interval, columns=['stream', 'device'], **tags)
        else:
            result = {}
        start_row = {}
        if add_prev:
            prev_data = self.query(rstart - add_prev, rstart, single=1, **tags)
            for key, table in prev_data.items():
                curve = result.get(key)
                first = table[0]
                if first[1] is not None:
                    if curve:
                        if first[0] < curve[0][0]:
                            if pivot:
                                curve.insert(0, (rstart,) + tuple(first[1:]))
                                # start_row.setdefault(key[1:], {})[key[0]] = first[1]
                            else:
                                curve.insert(0, tuple(first))
                    else:
                        result[key] = table
        if add_end:
            self.complete(result, stop)
        if merge:
            single_merge = isinstance(merge, str)
            if single_merge:
                merge = [merge]
            rows = []
            common_tags = summarize_tags(result.values(), True)
            col_keys = {}
            col_info = {}
            for key, curve in result.items():
                merge_tags = {k: curve.tags.get(k, '') for k in merge}
                for k, v in zip(curve.key_names, key):
                    merge_tags.setdefault(k, v)
                merge_key = tuple(zip(*merge_tags.items()))  # (<keys tuple>, <values tuple>)
                info = col_info.get(merge_key)
                if info is None:
                    col_idx = len(col_keys) + 1
                    col_keys[col_idx] = merge_key
                    col_info[merge_key] = info = [col_idx, []]
                else:
                    col_idx = info[0]
                info[1].append(curve)
                assert curve.column_names[1] == '_value'
                for row in curve:
                    rows.append((row[0], row[1], col_idx))
                # merged.append((merge_key, curve))
            rows.sort(key=lambda x: x[0])
            if pivot:
                header = []
                for merge_key, (col_idx, curves) in col_info.items():
                    tags = summarize_tags(curves)
                    primary = tags.pop(merge[0], None)
                    primary = [primary] if primary else []
                    header.append(' '.join(primary + [f"{k}={v}" for k, v in tags.items() if k not in common_tags]))
                result = Table(common_tags, (), ('_time',) + tuple(header))
                values = [0] + [None] * len(col_keys)
                for row in rows:
                    col_nr = row[2]
                    values[col_nr] = row[1]
                    if row[0] > values[0]:
                        values[0] = row[0]
                        result.append(tuple(values))
                    elif row[0] < values[0]:
                        raise ValueError(f'{rstart} {values[0]} {row[0]}')
            else:
                result = {}
                by_idx = {}
                for merge_key, (col_idx, curves) in col_info.items():
                    tags = summarize_tags(curves)
                    primary = tags.get(merge[0], '_value')
                    final_key = primary if single_merge else merge_key[1][:len(merge)]
                    table = result.get(final_key)
                    if table is None:
                        result[final_key] = table = Table(tags, merge_key[0], ('_time', primary))
                    else:
                        table.tags.update(tags)  # for previously undefined units
                    by_idx[col_idx] = table
                for row in rows:
                    by_idx[row[2]].append((row[0], row[1]))
        return result

    @staticmethod
    def complete(curve_dict, end_time=0, tag=None):
        """complete to end_time

        if tag is given, end_time is a dict <tag value> of <end time>
        """
        if tag is None:
            end_time_dict = {}
        else:
            end_time_dict, end_time = end_time, 0
        for curve in curve_dict.values():
            if len(curve):
                tlast, value = curve[-1]
                etime = end_time_dict.get(curve.tags.get(tag), end_time)
                if value is not None and tlast < etime:
                    curve.append((etime, value))

    def export(self, start, stop, measurement=('*.value', '*.target'), field='float',
               interval=None, add_prev=3600, add_end=False, timeoffset=None, none='', **tags):
        result = self.curves(start, stop, measurement, field, interval, add_prev, add_end,
                             merge=('_measurement', 'device', 'stream'), pivot=True, **tags)
        if timeoffset is None:
            timeoffset = int(start)
        result.tags.pop('_field', None)
        rows = [f"# {' '.join(f'{k}={v}' for k, v in result.tags.items())}"]
        rows.extend(f'# col {i} {k}' for i, k in enumerate(result.column_names))
        rows.extend(result.to_csv_rows(timeoffset, none=none))
        rows.append('')
        return '\n'.join(rows)

    def add_float(self, value, key, tags, ts):
        self._add_point('.'.join(key), 'float', -0.0 if value is None else float(value), ts, tags)

    def add_error(self, value, key, tags, ts):
        self._add_point('.'.join(key), 'error', '' if value is None else str(value), ts, tags)

    def get_streams(self, instrument=None, stream=None, device=None,
                    start=None, end=None, include_finished=False, **tags):
        """get streams for one or all instruments

        :param instrument: None when looking for all instruments
        :param stream: None, a comma separated string or a sequence of streams
        :param device: None or a comma separated string
        :param start: None or start time. None means 'since ever'
        :param end: None or end time. None means now (or more precise 'in a year')
        :param include_finished: whether finished streams are to be included (False by default)
        :return: dict <stream> of tags

        Remark: an assignment of an instrument to a stream persists, even when the stream gets off
        """
        if end is not None:
            end = end + 1
        if stream:
            if isinstance(stream, str):
                stream = stream.split(',')
            else:
                stream = list(stream)
            tags['stream'] = stream[0] if len(stream) == 1 else stream
        if device:
            tags['device'] = device
        before = self.query(None, start, _measurement='_stream_', _field='on',
                            instrument=instrument, single=1, **tags)
        if start == end:
            during = {}
        else:
            during = self.query(start, end, _measurement='_stream_', _field='on',
                                instrument=instrument, **tags)
        all_entries = {}
        # print('during', set(during))
        # for key, table in before.items():
        #     print(key, type(table))
        for key in set(before) | set(during):
            for tables in (before, during):
                table = tables.get(key, ())
                if table:
                    stream = table.tags.get('stream')
                for row in table:
                    all_entries.setdefault(stream, []).append((row, table.tags))
        result = {}
        for stream in sorted(all_entries):
            entries = all_entries[stream]
            current = None
            last = None
            instrument = None
            for entry in sorted(entries, key=lambda e: e[0][0]):
                (ts, flag), tags = entry
                if flag:
                    if 'instrument' in tags:
                        instrument = tags['instrument']
                    elif instrument:
                        # keep instrument from previous assignments
                        tags['instrument'] = instrument
                    current = [ts, tags]
                elif current:
                    if ts > current[0] + 60:
                        # else its probably not containing real data
                        last = current
                    current = None
            if include_finished:
                current = last
            if current:
                tags = current[1]
                ins = tags.get('instrument')
                if ins == '0':
                    tags.pop('instrument')
                result[stream] = tags
        return result

    def get_experiments(self, start=None, end=None, stream=None, **tags):
        """get experiments (periods with the same device/stream/instrument combination)

        :param start: start of time period
        :param end: end of time period
        :return: dict <key> of dict <device combi> of list of [start, end]
           where <key> is ('instrument', <instrument>) or ('stream', <stream>)
           and <device combi> is a tuple (tuple of streams, tuple of devices)
        """

        interval = 1
        gap = 600
        if start is None:
            previous = {}
        else:
            previous = self.query(None, start, _measurement='_stream_', _field='on', interval=interval,
                                  stream=stream, device=None, instrument=None, single=1, **tags)
        if end is None:
            nextrows = {}
        else:
            nextrows = self.query(end, None, _measurement='_stream_', _field='on', interval=interval,
                                  stream=stream, device=None, instrument=None, single=-1, **tags)
        start, end = abs_range(start, end)
        inperiod = self.query(start, end, _measurement='_stream_', _field='on', interval=interval,
                              stream=stream, device=None, instrument=None, **tags)
        # prepend previous to the items in period or create if not there
        for key, rows in previous.items():
            if key in inperiod:
                inperiod[key].insert(0, rows[0])
            else:
                inperiod[key] = rows

        # append items after the ones in period, ignoring keys not present in period
        # in the same go, create by_stream dict, joining tables with common stream
        by_stream = {}  # dict <stream> of [<ts>, <flag>, <instrument>, <device>]
        for key, table in inperiod.items():
            nextrow = nextrows.get(key)
            if nextrow and not nextrow[0][1]:
                table.extend(nextrow)
            stream, instrument, device = [table.tags.get(k, '') for k in ('stream', 'instrument', 'device')]
            elist = by_stream.setdefault(stream, [])
            for row in table:
                elist.append([row[0], row[1], stream, device, instrument])
        # combine now by either instrument or stream, if instrument is undefined (='0')
        by_key = {}
        for stream, rows in by_stream.items():
            rows.sort()
            instrument = '0'
            for row in rows:
                if not row[-1]:
                    row[-1] = instrument
                else:
                    instrument = row[-1]
                key = ('stream', stream) if instrument == '0' else ('instrument', instrument)
                by_key.setdefault(key, []).append(row)
        result = {}
        for key, rows in by_key.items():
            devices = {}
            current = {}
            prevcombi = None
            chunk = None
            for ts, flag, stream, device, _ in rows:
                ts = max(start, int(ts))
                if flag:
                    devices[stream] = device
                else:
                    devices.pop(stream, None)
                devcombi = tuple(zip(*sorted(devices.items())))
                if devcombi != prevcombi:
                    if prevcombi:  # device(s) removed
                        prevend = min(ts, chunk[1])
                        if prevend - chunk[0] < gap:
                            current.pop(prevcombi)
                        else:
                            chunk[1] = prevend
                    if devcombi:  # device(s) added
                        chunks = current.setdefault(devcombi, [])
                        if chunks:
                            prevbeg, prevend = chunks[-1]
                            # merge when joining or started at the same day
                            merge = prevend + gap > ts or sameday(prevbeg, ts)
                        else:
                            merge = False
                        if merge:
                            chunk = chunks[-1]
                            chunk[1] = ETERNITY
                        else:
                            chunk = [ts, ETERNITY]
                            chunks.append(chunk)
                    else:
                        chunk = None
                    prevcombi = devcombi
            if current:
                result[key] = current
        return result

    def get_instrument(self, stream, ts=None, **tags):
        """get assigned instrument and stream state

        :param stream: the stream to look up
        :param ts: the time ot None for 'now'
        :param tags: tags to further filter the result

        :return: <instrument>, <timestamp>
           where <instrument> is the instrument assigned to stream <stream> at ts
           amd <timestamp> is the time when this stream was on last time before ts or None when it is off
        """
        if ts is None:
            ts = int(time.time())
        reply = self.query(None, int(ts) + 1, _measurement='_stream_', _field='on',
                           stream=stream, single=1, **tags)
        instrument, lastts = None, None
        if reply:
            for table in sorted(reply.values(), key=lambda r: r[0][0]):
                ins = table.tags.get('instrument')
                row = table[-1]
                lastts = row[0] if row[1] else None
                if ins:
                    instrument = None if ins == '0' else ins
        return instrument, lastts

    def set_instrument(self, stream, instrument, ts=None, **tags):
        """set stream and instrument on or off

        :param stream: the uri of the stream
        :param instrument: or "0" to unassign the instrument or None when switching the stream off
        :param ts: the time or None when now
        """
        flag = instrument is not None
        if flag and instrument != '0':
            # in case an real instrument is given and no instrument is assigned yet
            # we predate the assignment to the start of the stream
            try:
                previns, prevts = self.get_instrument(stream, ts, **tags)
                if prevts is not None and (previns is None or (ts or ETERNITY) < prevts):
                    ts = prevts + 0.001
            except Exception as e:
                logging.warning('Exception in get_instrument: %r', e)
        tags['stream'] = stream
        if flag:
            tags['instrument'] = instrument
        self._add_point('_stream_', 'on', flag, ts, tags)

    def remove_experiment(self, stream, ts=None, **tags):
        if ts is not None:
            ts += 1
        reply = self.query(None, ts, _measurement='_stream_', _field='on',
                           stream=stream, single=1, **tags)
        tagset = set(tags) | {'stream'}
        tagset.discard('instrument')
        for table in reply.values():
            ts, flag = table[-1][:2]
            if flag:
                addtags = {k: v for k, v in table.tags.items()
                           if k not in {'instrument', '_measurement', '_field'}}
                self._add_point('_stream_', 'on', False, ts + 0.001,
                                addtags)
        self.flush()

    def add_stream(self, value, tags, key, ts):
        if value == '':  # unknown instrument
            value = self.instrument or self.instrument_by_stream.get(key, '0')
        self.set_instrument(key, value, ts, **tags)