rogged/libs/combat/attack.zig

const c = @import("c.zig");
const event = @import("event.zig");
const effects = @import("effects.zig");

fn rng(min: c_int, max: c_int) c_int {
    return c.rng_int(min, max);
}

fn applyResistance(damage: c_int, resistance: c_int) c_int {
    var r = resistance;
    if (r > 75) r = 75;
    const factor = 100 - r;
    var result = @divTrunc(damage * factor, 100);
    if (result < 1) result = 1;
    return result;
}

fn rollProc(
    target_effects: [*c]c.StatusEffect,
    target_count: [*c]c_int,
    dmg_class: c.DamageClass,
    status_chance: c_int,
) c.StatusEffectType {
    if (status_chance <= 0 or rng(0, 99) >= status_chance)
        return c.EFFECT_NONE;

    const eff_type = effects.procForClass(dmg_class);
    if (eff_type == c.EFFECT_NONE)
        return c.EFFECT_NONE;

    const params = effects.paramsFor(eff_type);
    effects.apply(target_effects, target_count, eff_type, params.duration, params.intensity);
    return eff_type;
}

pub fn playerAttack(p: [*c]c.Player, e: [*c]c.Enemy) void {
    if (p == null or e == null) return;
    if (e[0].alive == 0) return;

    event.reset();

    if (e[0].dodge > 0 and rng(0, 99) < e[0].dodge) {
        event.last.is_player_damage = 0;
        event.last.was_dodged = 1;
        event.last.message = "Enemy dodged!";
        return;
    }

    // Read weapon stats or unarmed defaults
    var dmg_class: c.DamageClass = c.DMG_IMPACT;
    var crit_chance: c_int = c.UNARMED_CRIT_CHANCE;
    var crit_mult: c_int = c.UNARMED_CRIT_MULT;
    var status_chance: c_int = c.UNARMED_STATUS_CHANCE;

    if (p[0].has_weapon != 0) {
        dmg_class = p[0].equipped_weapon.dmg_class;
        crit_chance = p[0].equipped_weapon.crit_chance;
        crit_mult = p[0].equipped_weapon.crit_multiplier;
        status_chance = p[0].equipped_weapon.status_chance;
    }

    var base_attack = p[0].attack;
    if (effects.has(&p[0].effects, p[0].effect_count, c.EFFECT_WEAKEN))
        base_attack -= c.WEAKEN_ATTACK_REDUCTION;
    if (base_attack < 1) base_attack = 1;

    var damage = base_attack;

    if (rng(0, 99) < crit_chance) {
        damage = @divTrunc(damage * crit_mult, 100);
        event.last.is_critical = 1;
    }

    const variance = rng(80, 120);
    damage = @divTrunc(damage * variance, 100);
    if (damage < 1) damage = 1;

    const res_index: usize = @intCast(dmg_class);
    if (res_index < c.NUM_DMG_CLASSES) {
        damage = applyResistance(damage, e[0].resistance[res_index]);
    }

    if (damage == 0) {
        event.last.damage = 0;
        event.last.is_player_damage = 0;
        event.last.message = "No effect!";
        return;
    }

    if (e[0].block > 0 and rng(0, 99) < 30) {
        var blocked = e[0].block;
        if (blocked > damage) blocked = damage;
        damage -= blocked;
        if (damage < 1) damage = 1;
        event.last.was_blocked = 1;
        event.last.block_amount = blocked;
    }

    e[0].hp -= damage;
    event.last.damage = damage;
    event.last.is_player_damage = 0;

    const applied = rollProc(&e[0].effects, &e[0].effect_count, dmg_class, status_chance);
    event.last.applied_effect = applied;

    if (e[0].hp <= 0) {
        e[0].hp = 0;
        e[0].alive = 0;
        event.last.message = "Enemy killed!";
    } else if (applied != c.EFFECT_NONE) {
        event.last.message = switch (applied) {
            c.EFFECT_BLEED => "Hit! Bleeding!",
            c.EFFECT_STUN => "Hit! Stunned!",
            c.EFFECT_WEAKEN => "Hit! Weakened!",
            c.EFFECT_BURN => "Hit! Burning!",
            c.EFFECT_POISON => "Hit! Poisoned!",
            else => "You hit",
        };
    } else if (event.last.is_critical != 0) {
        event.last.message = "Critical hit!";
    } else {
        event.last.message = "You hit";
    }
}

pub fn enemyAttack(e: [*c]c.Enemy, p: [*c]c.Player) void {
    if (e == null or p == null) return;
    if (e[0].alive == 0) return;

    event.reset();
    event.last.is_player_damage = 1;

    if (p[0].dodge > 0 and rng(0, 99) < p[0].dodge) {
        event.last.was_dodged = 1;
        event.last.message = "You dodged!";
        return;
    }

    var base_damage = e[0].attack;
    if (effects.has(&e[0].effects, e[0].effect_count, c.EFFECT_WEAKEN))
        base_damage -= c.WEAKEN_ATTACK_REDUCTION;
    base_damage -= p[0].defense;
    if (base_damage < 1) base_damage = 1;

    var damage = base_damage;

    const e_crit_chance = if (e[0].crit_chance > 0) e[0].crit_chance else c.ENEMY_CRIT_CHANCE;
    const e_crit_mult = if (e[0].crit_mult > 0) e[0].crit_mult else c.ENEMY_CRIT_MULT;
    if (rng(0, 99) < e_crit_chance) {
        damage = @divTrunc(damage * e_crit_mult, 100);
        event.last.is_critical = 1;
    }

    const variance = rng(80, 120);
    damage = @divTrunc(damage * variance, 100);
    if (damage < 1) damage = 1;

    if (p[0].block > 0 and rng(0, 99) < 30) {
        var blocked = p[0].block;
        if (blocked > damage) blocked = damage;
        damage -= blocked;
        if (damage < 1) damage = 1;
        event.last.was_blocked = 1;
        event.last.block_amount = blocked;
    }

    p[0].hp -= damage;
    event.last.damage = damage;

    const applied = rollProc(&p[0].effects, &p[0].effect_count, e[0].dmg_class, e[0].status_chance);
    event.last.applied_effect = applied;

    if (p[0].hp <= 0) {
        p[0].hp = 0;
        event.last.message = "You died!";
    } else if (applied != c.EFFECT_NONE) {
        event.last.message = switch (applied) {
            c.EFFECT_POISON => "Hit! Poisoned!",
            c.EFFECT_BLEED => "Hit! Bleeding!",
            c.EFFECT_STUN => "Hit! Stunned!",
            c.EFFECT_BURN => "Hit! Burning!",
            c.EFFECT_WEAKEN => "Hit! Weakened!",
            else => "Hit",
        };
    } else if (event.last.was_blocked != 0) {
        event.last.message = "Blocked some damage";
    } else if (event.last.is_critical != 0) {
        event.last.message = "Critical!";
    } else {
        event.last.message = "Hit";
    }
}