roguelike-game/src/melee_combat_system.rs

use ::rltk::{RandomNumberGenerator, RGB};
use ::specs::prelude::*;

use crate::components::{
    Attributes, HungerClock, HungerState, Name, Pools, Skill, Skills, SufferDamage, WantsToMelee,
};
use crate::game_log::GameLog;
use crate::gamesystem::skill_bonus;
use crate::particle_system::ParticleBuilder;
use crate::Position;

pub struct MeleeCombatSystem {}

impl<'a> System<'a> for MeleeCombatSystem {
    #[allow(clippy::type_complexity)]
    type SystemData = (
        Entities<'a>,
        WriteExpect<'a, GameLog>,
        WriteStorage<'a, WantsToMelee>,
        ReadStorage<'a, Name>,
        ReadStorage<'a, Attributes>,
        ReadStorage<'a, Skills>,
        WriteStorage<'a, SufferDamage>,
        WriteExpect<'a, ParticleBuilder>,
        ReadStorage<'a, Position>,
        ReadStorage<'a, HungerClock>,
        ReadStorage<'a, Pools>,
        WriteExpect<'a, RandomNumberGenerator>,
    );

    fn run(&mut self, data: Self::SystemData) {
        let (
            entities,
            mut log,
            mut wants_melee,
            names,
            attributes,
            skills,
            mut inflict_damage,
            mut particle_builder,
            positions,
            hunger_clock,
            pools,
            mut rng,
        ) = data;

        for (entity, wants_melee, name, attacker_attributes, attacker_skills, attacker_pools) in (
            &entities,
            &wants_melee,
            &names,
            &attributes,
            &skills,
            &pools,
        )
            .join()
        {
            // Are the attacker and defender alive? Only attack if they are
            let target_pools = pools.get(wants_melee.target).unwrap();
            let target_attributes = attributes.get(wants_melee.target).unwrap();
            let target_skills = skills.get(wants_melee.target).unwrap();
            if attacker_pools.hit_points.current > 0 && target_pools.hit_points.current > 0 {
                let target_name = names.get(wants_melee.target).unwrap();

                let natural_roll = rng.roll_dice(1, 20);
                let attribute_hit_bonus = attacker_attributes.might.bonus;
                let skill_hit_bonus = skill_bonus(Skill::Melee, &*attacker_skills);
                let weapon_hit_bonus = 0; // TODO: Once weapons support this
                let mut status_hit_bonus = 0;
                if let Some(hc) = hunger_clock.get(entity) {
                    // Well-Fed grants +1
                    if hc.state == HungerState::WellFed {
                        status_hit_bonus += 1;
                    }
                }
                let modified_hit_roll = natural_roll
                    + attribute_hit_bonus
                    + skill_hit_bonus
                    + weapon_hit_bonus
                    + status_hit_bonus;

                let base_armor_class = 10;
                let armor_quickness_bonus = target_attributes.quickness.bonus;
                let armor_skill_bonus = skill_bonus(Skill::Defense, &*target_skills);
                let armor_item_bonus = 0; // TODO: Once armor supports this
                let armor_class =
                    base_armor_class + armor_quickness_bonus + armor_skill_bonus + armor_item_bonus;

                if natural_roll != 1 && (natural_roll == 20 || modified_hit_roll > armor_class) {
                    // Target hit! Until we support weapons, we're going with 1d4
                    let base_damage = rng.roll_dice(1, 4);
                    let attr_damage_bonus = attacker_attributes.might.bonus;
                    let skill_damage_bonus = skill_bonus(Skill::Melee, &*attacker_skills);
                    let weapon_damage_bonus = 0;

                    let damage = i32::max(
                        0,
                        base_damage
                            + attr_damage_bonus
                            + skill_hit_bonus
                            + skill_damage_bonus
                            + weapon_damage_bonus,
                    );
                    SufferDamage::new_damage(&mut inflict_damage, wants_melee.target, damage);
                    log.append(format!(
                        "{} hits {} for {} hp.",
                        &name.name, &target_name.name, damage
                    ));

                    if let Some(pos) = positions.get(wants_melee.target) {
                        particle_builder.request(
                            pos.x,
                            pos.y,
                            RGB::named(rltk::ORANGE),
                            RGB::named(rltk::BLACK),
                            rltk::to_cp437('‼'),
                            200.0,
                        );
                    }
                } else if natural_roll == 1 {
                    // Natural 1 miss
                    log.append(format!(
                        "{} considers attacking {}, but misjudges the timing.",
                        name.name, target_name.name
                    ));
                    if let Some(pos) = positions.get(wants_melee.target) {
                        particle_builder.request(
                            pos.x,
                            pos.y,
                            RGB::named(rltk::BLUE),
                            RGB::named(rltk::BLACK),
                            rltk::to_cp437('‼'),
                            200.0,
                        );
                    }
                } else {
                    // Miss
                    log.append(format!(
                        "{} attacks {}, but can't connect",
                        name.name, target_name.name
                    ));
                    if let Some(pos) = positions.get(wants_melee.target) {
                        particle_builder.request(
                            pos.x,
                            pos.y,
                            RGB::named(rltk::CYAN),
                            RGB::named(rltk::BLACK),
                            rltk::to_cp437('‼'),
                            200.0,
                        );
                    }
                }
            }
        }

        wants_melee.clear();
    }
}