use ::rltk::RandomNumberGenerator;
use ::specs::prelude::*;

use crate::components::{EntityMoved, MoveMode, Movement, MyTurn, Position, Viewshed};
use crate::{spatial, tile_walkable, Map};

pub struct DefaultMoveAI {}

impl<'a> System<'a> for DefaultMoveAI {
    #[allow(clippy::type_complexity)]
    type SystemData = (
        WriteStorage<'a, MyTurn>,
        WriteStorage<'a, MoveMode>,
        WriteStorage<'a, Position>,
        ReadExpect<'a, Map>,
        WriteStorage<'a, Viewshed>,
        WriteStorage<'a, EntityMoved>,
        WriteExpect<'a, RandomNumberGenerator>,
        Entities<'a>,
    );

    fn run(&mut self, data: Self::SystemData) {
        let (
            mut turns,
            mut move_mode,
            mut positions,
            map,
            mut viewsheds,
            mut entity_moved,
            mut rng,
            entities,
        ) = data;

        let mut turn_done: Vec<Entity> = Vec::new();
        for (entity, mut pos, mut mode, mut viewshed, _myturn) in (
            &entities,
            &mut positions,
            &mut move_mode,
            &mut viewsheds,
            &turns,
        )
            .join()
        {
            turn_done.push(entity);

            match &mut mode.mode {
                Movement::Static => {}
                Movement::Random => {
                    let mut x = pos.x;
                    let mut y = pos.y;

                    match rng.roll_dice(1, 5) {
                        1 => x -= 1,
                        2 => x += 1,
                        3 => y -= 1,
                        4 => y += 1,
                        _ => {}
                    }

                    if x > 0 && x < map.width - 1 && y > 0 && y < map.height - 1 {
                        let dest_idx = map.xy_idx(x, y);
                        if !spatial::is_blocked(dest_idx) {
                            let idx = map.xy_idx(pos.x, pos.y);
                            pos.x = x;
                            pos.y = y;
                            entity_moved
                                .insert(entity, EntityMoved {})
                                .expect("Unable to insert movement marker");
                            crate::spatial::move_entity(entity, idx, dest_idx);
                            viewshed.dirty = true;
                        }
                    }
                }
                Movement::RandomWaypoint { path } => {
                    if let Some(path) = path {
                        // We have a target - go there
                        let idx = map.xy_idx(pos.x, pos.y);
                        if path.len() > 1 {
                            if !spatial::is_blocked(path[1]) {
                                pos.x = (path[1] as i32 % map.width) as i32;
                                pos.y = (path[1] as i32 / map.width) as i32;
                                entity_moved
                                    .insert(entity, EntityMoved {})
                                    .expect("Unable to insert movement marker");

                                let new_idx = map.xy_idx(pos.x, pos.y);
                                spatial::move_entity(entity, idx, new_idx);
                                viewshed.dirty = true;
                                path.remove(0); // Remove the first step in the path
                            }
                        } else {
                            // Otherwise we wait a turn to see if the path clears up
                            mode.mode = Movement::RandomWaypoint { path: None };
                        }
                    } else {
                        let target_x = rng.roll_dice(1, map.width - 2);
                        let target_y = rng.roll_dice(1, map.height - 2);
                        let idx = map.xy_idx(target_x, target_y);
                        if tile_walkable(map.tiles[idx]) {
                            let path = ::rltk::a_star_search(
                                map.xy_idx(pos.x, pos.y) as i32,
                                map.xy_idx(target_x, target_y) as i32,
                                &*map,
                            );
                            if path.success && path.steps.len() > 1 {
                                mode.mode = Movement::RandomWaypoint {
                                    path: Some(path.steps),
                                };
                            }
                        }
                    }
                }
            }
        }

        // Remove turn marker for those that are done
        for done in turn_done.iter() {
            turns.remove(*done);
        }
    }
}