#!/usr/bin/env python3

from abc import ABC, abstractmethod
import logging
import os
import random
import re
import time
from typing import Any, Callable, List, Optional, Set, Tuple

from pyutils.datetimes import datetime_utils

import kiosk_constants
import trigger


logger = logging.getLogger(__file__)


class chooser(ABC):
    """Base class of a thing that chooses pages"""

    def __init__(self):
        pass

    def get_page_list(self) -> List[str]:
        now = time.time()
        valid_filename = re.compile("([^_]+)_(\d+)_([^\.]+)\.html")
        filenames = []
        pages = [
            f
            for f in os.listdir(kiosk_constants.pages_dir)
            if os.path.isfile(os.path.join(kiosk_constants.pages_dir, f))
        ]
        for page in pages:
            result = re.match(valid_filename, page)
            if result is not None:
                if result.group(3) != "none":
                    freshness_requirement = int(result.group(3))
                    last_modified = int(
                        os.path.getmtime(os.path.join(kiosk_constants.pages_dir, page))
                    )
                    age = now - last_modified
                    if age > freshness_requirement:
                        logger.warning(
                            f'chooser: "{page}" is too old.'
                        )
                        continue
                logger.info(
                    f'chooser: candidate page: "{page}"'
                )
                filenames.append(page)
        return filenames

    @abstractmethod
    def choose_next_page(self) -> Any:
        pass


class weighted_random_chooser(chooser):
    """Chooser that does it via weighted RNG."""

    def __init__(self, filter_list: Optional[List[Callable[[str], bool]]]) -> None:
        super().__init__()
        self.last_choice = None
        self.valid_filename = re.compile("([^_]+)_(\d+)_([^\.]+)\.html")
        self.pages: Optional[List[str]] = None
        self.count = 0
        self.filter_list: List[Callable[[str], bool]] = []
        if filter_list is not None:
            self.filter_list.extend(filter_list)
        self.filter_list.append(self.dont_choose_page_twice_in_a_row_filter)

    def dont_choose_page_twice_in_a_row_filter(self, choice: str) -> bool:
        if self.last_choice is not None and choice == self.last_choice:
            return False
        self.last_choice = choice
        return True

    def choose_next_page(self) -> Any:
        if self.pages is None or self.count % 100 == 0:
            logger.info('chooser: refreshing the candidate pages list.')
            self.pages = self.get_page_list()

        total_weight = 0
        weights = []
        for page in self.pages:
            result = re.match(self.valid_filename, page)
            if result is not None:
                weight = int(result.group(2))
                weights.append(weight)
                total_weight += weight
        if total_weight <= 0:
            raise Exception

        while True:
            random_pick = random.randrange(0, total_weight - 1)
            so_far = 0
            for x in range(0, len(weights)):
                so_far += weights[x]
                if so_far > random_pick:
                    break
            choice = self.pages[x]

            # Allow filters list to suppress pages.
            choice_is_filtered = False
            for f in self.filter_list:
                if not f(choice):
                    choice_is_filtered = True
                    break
            if choice_is_filtered:
                continue

            # We're good...
            self.count += 1
            return choice


class weighted_random_chooser_with_triggers(weighted_random_chooser):
    """Same as WRC but has trigger events"""

    def __init__(
        self,
        trigger_list: Optional[List[trigger.trigger]],
        filter_list: List[Callable[[str], bool]],
    ) -> None:
        super().__init__(filter_list)
        self.trigger_list: List[trigger.trigger] = []
        if trigger_list is not None:
            self.trigger_list.extend(trigger_list)
        self.page_queue: Set[Tuple[str, int]] = set(())

    def check_for_triggers(self) -> bool:
        triggered = False
        for t in self.trigger_list:
            x = t.get_triggered_page_list()
            if x is not None and len(x) > 0:
                for y in x:
                    self.page_queue.add(y)
                    logger.info(f'chooser: noticed active trigger {y}')
                    triggered = True
        return triggered

    def choose_next_page(self) -> Tuple[str, bool]:
        if self.pages is None or self.count % 100 == 0:
            logger.info('chooser: refreshing the candidates page list')
            self.pages = self.get_page_list()

        triggered = self.check_for_triggers()

        # First try to satisfy from the page queue.
        if len(self.page_queue) > 0:
            logger.info('chooser: page queue has entries; pulling choice from there.')
            page = None
            priority = None
            for t in self.page_queue:
                if priority is None or t[1] > priority:
                    page = t[0]
                    priority = t[1]
            assert(page is not None)
            assert(priority is not None)
            self.page_queue.remove((page, priority))
            return (page, triggered)

        # Always show the clock in the middle of the night.
        now = datetime_utils.now_pacific()
        if now.hour < 6:
            for page in self.pages:
                if "clock" in page:
                    return (page, False)

        # Fall back on weighted random choice.
        return (weighted_random_chooser.choose_next_page(self), False)


# Test
# def filter_news_during_dinnertime(page):
#    now = datetime.datetime.now()
#    is_dinnertime = now.hour >= 17 and now.hour <= 20
#    return not is_dinnertime or not (
#        "cnn" in page
#        or "news" in page
#        or "mynorthwest" in page
#        or "seattle" in page
#        or "stranger" in page
#        or "twitter" in page
#        or "wsj" in page
#    )
# x = weighted_random_chooser_with_triggers([], [ filter_news_during_dinnertime ])
# print(x.choose_next_page())