#!/usr/bin/env python3
# Eryn Wells <eryn@erynwells.me>

'''Defines the core game engine.'''

import logging
import random
from dataclasses import dataclass
from typing import MutableSet

import tcod

from . import monsters
from .events import EventHandler
from .geometry import Direction, Size
from .map import Map
from .monsters import Monster
from .object import Entity, Hero

LOG = logging.getLogger('engine')
EVENT_LOG = logging.getLogger('events')

@dataclass
class Configuration:
    map_size: Size

class Engine:
    def __init__(self, event_handler: EventHandler, configuration: Configuration):
        self.event_handler = event_handler
        self.configuration = configuration

        self.rng = tcod.random.Random()
        self.map = Map(configuration.map_size)

        first_room = self.map.generator.rooms[0]
        hero_start_position = first_room.center
        self.hero = Hero(position=hero_start_position)

        self.entities: MutableSet[Entity] = {self.hero}
        for room in self.map.rooms:
            should_spawn_monster_chance = random.random()
            if should_spawn_monster_chance < 0.4:
                continue

            floor = list(room.walkable_tiles)
            while True:
                random_start_position = random.choice(floor)
                if not any(ent.position == random_start_position for ent in self.entities):
                    break

            for _ in range(2):
                spawn_monster_chance = random.random()
                if spawn_monster_chance > 0.8:
                    monster = Monster(monsters.Troll, position=random_start_position)
                else:
                    monster = Monster(monsters.Orc, position=random_start_position)

                LOG.info('Spawning monster %s', monster)
                self.entities.add(monster)

        self.update_field_of_view()

    def handle_event(self, event: tcod.event.Event):
        action = self.event_handler.dispatch(event)

        if not action:
            return

        action.perform(self, self.hero)

        directions = list(Direction.all())
        moved_entities: MutableSet[Entity] = {self.hero}

        for ent in self.entities:
            if ent == self.hero:
                continue

            while True:
                new_position = ent.position + random.choice(directions)
                overlaps_with_previously_moved_entity = any(new_position == moved_ent.position for moved_ent in moved_entities)
                if not overlaps_with_previously_moved_entity and self.map.tile_is_walkable(new_position):
                    ent.position = new_position
                    moved_entities.add(ent)
                    break

        self.update_field_of_view()

    def print_to_console(self, console):
        '''Print the whole game to the given console.'''
        self.map.print_to_console(console)

        for ent in self.entities:
            # Only print entities that are in the field of view
            if not self.map.visible[tuple(ent.position)]:
                continue
            ent.print_to_console(console)

    def update_field_of_view(self) -> None:
        '''Compute visible area of the map based on the player's position and point of view.'''
        self.map.visible[:] = tcod.map.compute_fov(
            self.map.tiles['transparent'],
            tuple(self.hero.position),
            radius=8)

        # Visible tiles should be added to the explored list
        self.map.explored |= self.map.visible