boardgame-core/src/samples/slay-the-spire-like/system/combat/triggers.ts

import {CombatGameContext} from "./types";
import {
    addEntityEffect,
    addItemEffect,
    getAliveEnemies, onEntityPostureDamage,
    onEntityEffectUpkeep,
    onPlayerItemEffectUpkeep, onItemDiscard, onItemPlay
} from "@/samples/slay-the-spire-like/system/combat/effects";
import {promptMainAction} from "@/samples/slay-the-spire-like/system/combat/prompts";
import {moveToRegion, shuffle} from "@/core/region";
import {createMiddlewareChain} from "@/utils/middleware";
import {EffectData} from "@/samples/slay-the-spire-like/system/types";
import {getAdjacentItems} from "@/samples/slay-the-spire-like/system/grid-inventory";
import {GameItemMeta} from "@/samples/slay-the-spire-like/system/progress";

type TriggerTypes = {
    onCombatStart: {},
    onTurnStart: { entityKey: "player" | string, },
    onTurnEnd: { entityKey: "player" | string, },
    onShuffle: {},
    onCardPlayed: { cardId: string, targetId?: string },
    onCardDiscarded: { cardId: string,  },
    onCardDrawn: { cardId: string,  },
    onDraw: {count: number},
    onEffectApplied: { effect: EffectData, entityKey: "player" | string, stacks: number, cardId?: string },
    onHpChange: { entityKey: "player" | string, amount: number},
    onDamage: { entityKey: "player" | string, amount: number, dealt?: number, prevented?: number},
}

function createTriggers(){
    const triggers = {
        onCombatStart: createTrigger("onCombatStart"),
        onTurnStart: createTrigger("onTurnStart", async ctx => {
            await ctx.game.produceAsync(draft => {
                const entity = ctx.entityKey === "player" ? draft.player : draft.enemies.find(e => e.id === ctx.entityKey);
                if(entity) onEntityEffectUpkeep(entity);
                if(entity === draft.player)
                    onPlayerItemEffectUpkeep(draft.player);
            })
        }),
        onTurnEnd: createTrigger("onTurnEnd", async ctx => {
            if(ctx.entityKey !== "player")return;
            const {regions} = ctx.game.value.player.deck;
            for(const cardId of Object.values(regions.hand.childIds)){
                await triggers.onCardDiscarded.execute(ctx.game,{cardId});
            }
            await ctx.game.produceAsync(draft => draft.player.energy = draft.player.maxEnergy);
            await triggers.onDraw.execute(ctx.game,{count: 5});
        }),
        onShuffle: createTrigger("onShuffle", async ctx => {
            await ctx.game.produceAsync(draft => {
                const {cards, regions} = draft.player.deck;
                for(const cardId of Object.values(regions.discardPile.childIds))
                    moveToRegion(cards[cardId], regions.discardPile, regions.drawPile);
                shuffle(regions.drawPile, cards, ctx.game.rng);
            });
        }),
        onCardPlayed: createTrigger("onCardPlayed", async ctx => {
            await ctx.game.produceAsync(draft => {
                const {cards, regions} = draft.player.deck;
                moveToRegion(cards[ctx.cardId], regions.hand, regions.discardPile);
                onItemPlay(draft.player, cards[ctx.cardId].itemId);
            });
        }),
        onCardDiscarded: createTrigger("onCardDiscarded", async ctx => {
            await ctx.game.produceAsync(draft => {
                const {cards, regions} = draft.player.deck;
                moveToRegion(cards[ctx.cardId], regions.hand, regions.discardPile);
                onItemDiscard(draft.player, cards[ctx.cardId].itemId);
            });
        }),
        onCardDrawn: createTrigger("onCardDrawn", async ctx => {
            await ctx.game.produceAsync(draft => {
                const {cards, regions} = draft.player.deck;
                moveToRegion(cards[ctx.cardId], regions.drawPile, regions.hand);
            });
        }),
        onDraw: createTrigger("onDraw", async ctx => {
            let toDraw = ctx.count;
            while(toDraw > 0){
                let inDraw = ctx.game.value.player.deck.regions.drawPile.childIds.length;
                if(inDraw <= 0) await triggers.onShuffle.execute(ctx.game,{});

                inDraw = ctx.game.value.player.deck.regions.drawPile.childIds.length;
                if(inDraw <= 0) break;

                const children = ctx.game.value.player.deck.regions.drawPile.childIds;
                const cardId = children[children.length - 1];
                await triggers.onCardDrawn.execute(ctx.game,{cardId});
                toDraw--;
            }
        }),
        onEffectApplied: createTrigger("onEffectApplied", async ctx => {
            if(ctx.effect.lifecycle === 'instant') return;

            if(ctx.effect.lifecycle.startsWith("item")) {
                if(ctx.cardId){
                    const card = ctx.game.value.player.deck.cards[ctx.cardId];
                    const nearby = getAdjacentItems<GameItemMeta>(ctx.game.value.inventory, card.itemId);
                    for(const itemId of nearby.keys()){
                        await ctx.game.produceAsync(draft => {
                            addItemEffect(draft.player, itemId, ctx.effect, ctx.stacks);
                        });
                    }
                }
                return;
            }
            
            await ctx.game.produceAsync(draft => {
                const entity = ctx.entityKey === "player" ? draft.player : draft.enemies.find(e => e.id === ctx.entityKey);
                if(entity) addEntityEffect(entity, ctx.effect, ctx.stacks);
            })
        }),
        onHpChange: createTrigger("onHpChange", async ctx => {
            await ctx.game.produceAsync(draft => {
                const entity = ctx.entityKey === "player" ? draft.player : draft.enemies.find(e => e.id === ctx.entityKey);
                if(!entity) return;
                entity.hp += ctx.amount;
                entity.isAlive = entity.hp > 0;
                draft.result = !draft.player.isAlive ? "defeat" : draft.enemies.every(e => !e.isAlive) ? "victory" : null;
            });
            if(ctx.game.value.result) throw ctx.game.value;
        }),
        onDamage: createTrigger("onDamage", async ctx => {
            const entity = ctx.entityKey === "player" ? ctx.game.value.player : ctx.game.value.enemies.find(e => e.id === ctx.entityKey);
            if(!entity || !entity.isAlive) return;
            const dealt = ctx.dealt = Math.min(Math.max(0,entity.hp), ctx.amount);
            ctx.prevented = ctx.amount - ctx.dealt;
            await ctx.game.produceAsync(draft => {
                onEntityPostureDamage(entity, dealt);
            });
            await triggers.onHpChange.execute(ctx.game,{entityKey: ctx.entityKey, amount: -ctx.amount});
        }),
    }
    return triggers;
}
export type Triggers = ReturnType<typeof createTriggers>
export function createStartWith(build: (triggers: Triggers) => void){
    const triggers = createTriggers();
    build(triggers);
    return async function(game: CombatGameContext){
        await triggers.onCombatStart.execute(game,{});
        
        try {
            while (true) {
                await triggers.onTurnStart.execute(game, {entityKey: "player"});
                while (true) {
                    const action = await promptMainAction(game);
                    if (action.action === "end-turn") break;
                    if (action.action === "play") {
                        // TODO: energy/use consumption handling
                        await triggers.onCardPlayed.execute(game, action);
                    }
                }
                await triggers.onTurnEnd.execute(game, {entityKey: "player"});

                for (const enemy of getAliveEnemies(game.value)) {
                    await triggers.onTurnStart.execute(game, {entityKey: enemy.id});
                }
                // TODO execute enemy intent, then update with new one here
                for (const enemy of getAliveEnemies(game.value)) {
                    await triggers.onTurnEnd.execute(game, {entityKey: enemy.id});
                }
            }
        }catch(e){
            if(e === game.value) return game.value.result;
            throw e;
        }
    }
}

type TriggerContext<TKey extends keyof TriggerTypes> = TriggerTypes[TKey] & { event: TKey, game: CombatGameContext };
function createTrigger<TKey extends keyof TriggerTypes>(event: TKey, fallback?: (ctx: TriggerContext<TKey>) => Promise<void>) {
    const {use, execute} = createMiddlewareChain<TriggerContext<TKey>,void>(fallback);
    return {
        use,
        execute: async (game: CombatGameContext, ctx: TriggerTypes[TKey]) => {
            const param = {...ctx, game, event};
            await execute(param);
            return param;
        },
    }
}