Dialogs engine

src/common/rpg/dialog.ts

@@ -0,0 +1,200 @@
+import { isDialog, type Dialog, type DialogChoice, type DialogNode } from "./types";
+
+type ConditionOperator = '==' | '!=' | '>' | '<' | '>=' | '<=' | 'null' | '~null';
+type ConditionValue = string | number | boolean | null;
+
+interface ParsedCondition {
+    variable: string;
+    negate: boolean;
+    operator?: ConditionOperator;
+    value?: ConditionValue;
+}
+
+function parseCondition(s: string): ParsedCondition {
+    // ~variable — falsy check, nothing else allowed
+    if (s.startsWith('~') && !s.includes(' '))
+        return { variable: s.slice(1), negate: true };
+
+    const spaceIdx = s.indexOf(' ');
+    if (spaceIdx === -1)
+        return { variable: s, negate: false };
+
+    const variable = s.slice(0, spaceIdx);
+    const rest = s.slice(spaceIdx + 1).trim();
+
+    if (rest === 'null') return { variable, negate: false, operator: 'null' };
+    if (rest === '~null') return { variable, negate: false, operator: '~null' };
+
+    const opMatch = rest.match(/^(==|!=|>=|<=|>|<)\s*(.+)$/);
+    if (!opMatch) throw new Error(`Invalid condition: "${s}"`);
+
+    const [, operator, rawValue] = opMatch;
+    let value: ConditionValue;
+    if (rawValue === 'null') value = null;
+    else if (rawValue === 'true') value = true;
+    else if (rawValue === 'false') value = false;
+    else if (!isNaN(Number(rawValue))) value = Number(rawValue);
+    else value = rawValue.replace(/^['"]|['"]$/g, '');
+
+    return { variable, negate: false, operator: operator as ConditionOperator, value };
+}
+
+function conditionVariable(s: string): string {
+    if (s.startsWith('~')) return s.slice(1);
+    const space = s.indexOf(' ');
+    return space === -1 ? s : s.slice(0, space);
+}
+
+export type DialogVariables = Record<string, string | number | boolean>;
+export type DialogActions = Record<string, (arg?: unknown) => Promise<void> | void>;
+
+export interface DialogRuntimeOptions {
+    variables: DialogVariables;
+    actions: DialogActions;
+}
+
+export interface DialogNodeView {
+    speaker: string;
+    text: string;
+    choices?: DialogChoice[];
+}
+
+export function validateDialog(
+    dialog: unknown,
+    conditions: string[],
+    actions: string[],
+    speakers: string[],
+): string[] {
+    if (!isDialog(dialog)) return ['invalid dialog structure'];
+
+    const errors: string[] = [];
+    const nodeIds = new Set(dialog.nodes.map(n => n.id));
+    const conditionSet = new Set(conditions);
+    const actionSet = new Set(actions);
+    const speakerSet = new Set(speakers);
+
+    if (!nodeIds.has(dialog.startNodeId))
+        errors.push(`startNodeId '${dialog.startNodeId}' does not match any node id`);
+
+    for (const node of dialog.nodes) {
+        if (!speakerSet.has(node.speaker))
+            errors.push(`node '${node.id}': unknown speaker '${node.speaker}'`);
+
+        if (node.nextNodeId !== undefined && !nodeIds.has(node.nextNodeId))
+            errors.push(`node '${node.id}': nextNodeId '${node.nextNodeId}' does not match any node id`);
+
+        for (const cond of node.conditions ?? []) {
+            const varName = conditionVariable(cond);
+            if (!conditionSet.has(varName))
+                errors.push(`node '${node.id}': unknown condition variable '${varName}'`);
+        }
+
+        for (const action of node.actions ?? [])
+            if (!actionSet.has(action.type))
+                errors.push(`node '${node.id}': unknown action type '${action.type}'`);
+
+        for (const choice of node.choices ?? [])
+            if (choice.nextNodeId !== undefined && !nodeIds.has(choice.nextNodeId))
+                errors.push(`node '${node.id}': choice '${choice.text}': nextNodeId '${choice.nextNodeId}' does not match any node id`);
+    }
+
+    return errors;
+}
+
+export function isValidDialog(
+    v: unknown,
+    conditions: string[],
+    actions: string[],
+    speakers: string[],
+): v is Dialog {
+    return validateDialog(v, conditions, actions, speakers).length === 0;
+}
+
+export class DialogEngine {
+    private readonly nodeMap: Map<string, DialogNode>;
+    private readonly startNodeId: string;
+    private currentNode: DialogNode | null = null;
+
+    constructor(
+        dialog: Dialog,
+        private readonly options: DialogRuntimeOptions,
+    ) {
+        this.nodeMap = new Map(dialog.nodes.map(n => [n.id, n]));
+        this.startNodeId = dialog.startNodeId;
+    }
+
+    async advance(nodeId?: string): Promise<DialogNodeView | null> {
+        let targetId = nodeId ?? this.currentNode?.nextNodeId ?? (this.currentNode === null ? this.startNodeId : undefined);
+
+        while (targetId !== undefined) {
+            const node = this.nodeMap.get(targetId);
+            if (!node) return null;
+
+            if (!this.evaluateConditions(node.conditions ?? [])) {
+                targetId = node.nextNodeId;
+                continue;
+            }
+
+            this.currentNode = node;
+
+            for (const action of node.actions ?? []) {
+                await this.options.actions[action.type]?.(action.arg);
+            }
+
+            const choices = this.filterChoices(node.choices);
+
+            return {
+                speaker: node.speaker,
+                text: node.text,
+                choices,
+            };
+        }
+
+        return null;
+    }
+
+    private filterChoices(choices?: DialogChoice[]): DialogChoice[] | undefined {
+        if (!choices) return undefined;
+        const filtered = choices.filter(choice => {
+            if (choice.nextNodeId === undefined) return true;
+            const target = this.nodeMap.get(choice.nextNodeId);
+            return target ? this.evaluateConditions(target.conditions ?? []) : false;
+        });
+        return filtered.length > 0 ? filtered : undefined;
+    }
+
+    private evaluateConditions(conditions: string[]): boolean {
+        return conditions.every(c => this.evaluateCondition(parseCondition(c)));
+    }
+
+    private evaluateCondition({ variable, negate, operator, value }: ParsedCondition): boolean {
+        const val = this.options.variables[variable];
+
+        if (operator === 'null') return val == null;
+        if (operator === '~null') return val != null;
+
+        if (operator === undefined)
+            return negate ? !Boolean(val) : Boolean(val);
+
+        if (operator === '==') return val === value;
+        if (operator === '!=') return val !== value;
+
+        if (typeof val !== 'number' || typeof value !== 'number') return false;
+        if (operator === '<') return val < value;
+        if (operator === '>') return val > value;
+        if (operator === '<=') return val <= value;
+        if (operator === '>=') return val >= value;
+
+        return false;
+    }
+
+    [Symbol.asyncIterator]() {
+        return this;
+    }
+
+    async next() {
+        const nextNode = await this.advance();
+        if (nextNode === null) return { done: true, value: null };
+        return { done: false, value: nextNode };
+    }
+}

src/common/rpg/types.ts

@@ -0,0 +1,55 @@
+export interface DialogAction {
+    type: string;
+    arg?: string | number | boolean | null;
+}
+
+export interface DialogChoice {
+    text: string;
+    nextNodeId?: string;
+}
+
+export interface DialogNode {
+    id: string;
+    speaker: string;
+    text: string;
+    nextNodeId?: string;
+    choices?: DialogChoice[];
+    conditions?: string[];
+    actions?: DialogAction[];
+}
+
+export interface Dialog {
+    nodes: DialogNode[];
+    startNodeId: string;
+}
+
+function isDialogAction(v: unknown): v is DialogAction {
+    if (typeof v !== 'object' || v === null) return false;
+    return typeof (v as Record<string, unknown>).type === 'string';
+}
+
+function isDialogChoice(v: unknown): v is DialogChoice {
+    if (typeof v !== 'object' || v === null) return false;
+    const c = v as Record<string, unknown>;
+    return typeof c.text === 'string'
+        && (c.nextNodeId === undefined || typeof c.nextNodeId === 'string');
+}
+
+function isDialogNode(v: unknown): v is DialogNode {
+    if (typeof v !== 'object' || v === null) return false;
+    const n = v as Record<string, unknown>;
+    return typeof n.id === 'string'
+        && typeof n.speaker === 'string'
+        && typeof n.text === 'string'
+        && (n.nextNodeId === undefined || typeof n.nextNodeId === 'string')
+        && (n.choices === undefined || (Array.isArray(n.choices) && n.choices.every(isDialogChoice)))
+        && (n.conditions === undefined || (Array.isArray(n.conditions) && n.conditions.every(v => typeof v === 'string')))
+        && (n.actions === undefined || (Array.isArray(n.actions) && n.actions.every(isDialogAction)));
+}
+
+export function isDialog(v: unknown): v is Dialog {
+    if (typeof v !== 'object' || v === null) return false;
+    const d = v as Record<string, unknown>;
+    return Array.isArray(d.nodes) && d.nodes.every(isDialogNode)
+        && typeof d.startNodeId === 'string';
+}

src/common/types.ts

@@ -0,0 +1,2 @@
+export type Key<T> = keyof T;
+export type Value<T, K extends Key<T> = Key<T>> = T[K];

src/games/playground/dialog.yml

@@ -0,0 +1,27 @@
+startNodeId: start
+
+nodes:
+  - id: start
+    speaker: npc
+    text: "Ah, traveler. I sense you seek passage through my gates."
+    nextNodeId: sword_path
+
+  - id: sword_path
+    speaker: npc
+    text: "I see you carry a blade. Warriors are always welcome here."
+    nextNodeId: no_sword_path
+    conditions:
+      - hasSword
+
+  - id: no_sword_path
+    speaker: npc
+    text: "You come unarmed? Brave, or perhaps foolish. You may still pass."
+    nextNodeId: end
+    conditions:
+      - ~hasSword
+
+  - id: end
+    speaker: npc
+    text: "Safe travels."
+    choices:
+      - text: "Farewell."

src/games/playground/index.tsx

@@ -1,34 +1,16 @@
-import { gameLoop } from "@common/game";
-import Input from "@common/input";
+import { DialogEngine, isValidDialog } from "@common/rpg/dialog";
+import dialogYml from './dialog.yml';
 
-const setup = () => {
-    let x = window.innerWidth / 2 - 16;
-    let y = window.innerHeight / 2 - 16;
-    const ball = document.createElement('div');
-
-    ball.style.display = 'block';
-    ball.style.width = '32px';
-    ball.style.height = '32px';
-    ball.style.borderRadius = '50%';
-    ball.style.backgroundColor = 'red';
-    ball.style.position = 'absolute';
-
-    document.body.append(ball);
-
-    const speed = Math.min(window.innerHeight, window.innerWidth);
-
-    return { x, y, speed, ball };
+export default async function main() {
+    // console.log(dialogYml);
+    if (isValidDialog(dialogYml, ['hasSword'], [], ['player', 'npc'])) {
+        const dialog = new DialogEngine(dialogYml, {
+            variables: { hasSword: false },
+            actions: {},
+        });
+        // console.log(await dialog.advance());
+        for await (const node of dialog) {
+            console.log(node);
+        }
+    }
 }
-
-const frame = (dt: number, state: ReturnType<typeof setup>) => {
-    const dx = Input.getHorizontal();
-    const dy = Input.getVertical();
-
-    state.x += state.speed * dx * dt;
-    state.y += state.speed * dy * dt;
-
-    state.ball.style.left = `${state.x}px`;
-    state.ball.style.top = `${state.y}px`;
-}
-
-export default gameLoop(setup, frame);