daggerheart/module/data/action/damageAction.mjs

import DHBaseAction from './baseAction.mjs';

export default class DHDamageAction extends DHBaseAction {
    static extraSchemas = ['damage', 'target', 'effects'];

    getFormulaValue(part, data) {
        let formulaValue = part.value;
        if (this.hasRoll && part.resultBased && data.system.roll.result.duality === -1) return part.valueAlt;

        const isAdversary = this.actor.type === 'adversary';
        if (isAdversary && this.actor.system.type === CONFIG.DH.ACTOR.adversaryTypes.horde.id) {
            const hasHordeDamage = this.actor.effects.find(
                x => x.name === game.i18n.localize('DAGGERHEART.CONFIG.AdversaryType.horde.label')
            );
            if (hasHordeDamage) return part.valueAlt;
        }

        return formulaValue;
    }

    async rollDamage(event, data) {
        const systemData = data.system ?? data;
        let formula = this.damage.parts.map(p => this.getFormulaValue(p, data).getFormula(this.actor)).join(' + '),
            damageTypes = [...new Set(this.damage.parts.reduce((a, c) => a.concat([...c.type]), []))];

        damageTypes = !damageTypes.length ? ['physical'] : damageTypes;

        if (!formula || formula == '') return;
        let roll = { formula: formula, total: formula },
            bonusDamage = [];

        if (isNaN(formula)) formula = Roll.replaceFormulaData(formula, this.getRollData(systemData));

        const config = {
            title: game.i18n.format('DAGGERHEART.UI.Chat.damageRoll.title', { damage: this.name }),
            roll: { formula },
            targets: systemData.targets.filter(t => t.hit) ?? data.targets,
            hasSave: this.hasSave,
            isCritical: systemData.roll?.isCritical ?? false,
            source: systemData.source,
            data: this.getRollData(),
            damageTypes,
            event
        };
        if (this.hasSave) config.onSave = this.save.damageMod;
        if (data.system) {
            config.source.message = data._id;
            config.directDamage = false;
        } else {
            config.directDamage = true;
        }

        roll = CONFIG.Dice.daggerheart.DamageRoll.build(config);
    }

    // get modifiers() {
    //     return [];
    // }
}