import { ISharedFunction } from './ISharedFunction';
import { ISharedFunctionCollection } from './ISharedFunctionCollection';

export class SharedFunctionCollection implements ISharedFunctionCollection {
    private readonly functionsByName = new Map<string, ISharedFunction>();

    public addFunction(func: ISharedFunction): void {
        if (!func) { throw new Error('undefined function'); }
        if (this.has(func.name)) {
            throw new Error(`function with name ${func.name} already exists`);
        }
        this.functionsByName.set(func.name, func);
    }

    public getFunctionByName(name: string): ISharedFunction {
        if (!name) { throw Error('undefined function name'); }
        const func = this.functionsByName.get(name);
        if (!func) {
            throw new Error(`called function is not defined "${name}"`);
        }
        return func;
    }

    private has(functionName: string) {
        return this.functionsByName.has(functionName);
    }
}