//monitor.js
export default {
    variables: new Map(),
    callback: null,
    listener: null,
    running: false,
    onMessage(e) {
        const variables = e.data.variables;
        if(!(Array.isArray(variables))) return;
        for(let v of variables) if(v && v.name && v.value !== undefined) this.update(v.name, v.value);
    },
    fromJSON(str) {
        if(typeof(str) != ‘string‘) return null;
        try { return JSON.parse(str); } catch { return null }
    },
    toJSON(obj, space) {
        return JSON.stringify(obj, null, space);
    },
    convertType(type, value) {
        if(typeof(value) == type) return value;

        switch(type) {
            case ‘table‘:
                if(!Array.isArray(value)) value = this.fromJSON(value);
                break;
            case ‘object‘:
                value = this.fromJSON(value);
                break;
            case ‘boolean‘:
                value = /^(false)|0$/i.test(value) ? false : Boolean(value);
                break;
            case ‘number‘:
                value = isNaN(value) ? 0 : Number(value);
                break;
            default:
                value = this.toJSON(value);
        }

        return value;
    },
    isInvalidType(type, value) {
        if(![‘string‘, ‘number‘, ‘boolean‘, ‘object‘, ‘table‘].includes(type)) return true;
        if(type == ‘table‘ && Array.isArray(value)) return false;
        if(type == ‘object‘ && !value) return true;
        if(typeof(value) == type) return false;
        return true;
    },
    start(callback) {
        if(this.running) return;
        if(typeof(callback) == ‘function‘) this.callback = callback;
        this.listener = e => this.onMessage(e);
        window.addEventListener(‘message‘, this.listener);
        this.running = true;
    },
    stop() {
        if(this.listener) window.removeEventListener(‘message‘, this.listener);
        this.running = false;
    },
    add(...variables) {
        for(let v of variables) this.variables.set(v.name, v);
    },
    remove(...names) {
        for(let n of names) this.variables.delete(names);
    },
    update(name, value, description, type) {
        if(!this.running || !this.variables.has(name)) return;
        const v = this.variables.get(name);
        if(typeof(type) == ‘string‘ && type != v.type) v.type = type;
        if(typeof(description) == ‘string‘ && description != v.description) v.description = description;
        value = this.convertType(v.type, value);
        if(this.isInvalidType(v.type, value)) return;
        if(value === v.value) return;
        const oldValue = v.value;
        v.value = value;
        if(this.callback) this.callback(name, value, oldValue);
    }
}