// https://www.logicbig.com/tutorials/misc/typescript/parameter-decorator.html

export function Inject(target: any, propertyKey: string, descriptor: PropertyDescriptor) {
    console.log("method decorator validate function invoked ");
    let originalMethod = descriptor.value;
    // # Wrapping the original method with wrapper function
    descriptor.value = async function (...args: any[]) {
        const injectedValues = await InjectDecoratorMetadata.inject(target, propertyKey, args)
        for(let [index, argValue] of args.entries()) {
            const iv : any | undefined = injectedValues.find( (iv: any) => iv[0] == index);
            if(iv)
                args[index] = iv[1]
        }
        let result = originalMethod.apply(this, args);
        return result;
    }
}

export class InjectDecoratorMetadata {
    private static map: Map<any, Map<string, number[]>> = new Map();

    static register(target: any, methodName: string, paramIndex: number, handler: Function): void {
        let paramMap: Map<string, number[]> | undefined= this.map.get(target);
        if (!paramMap) {
            paramMap = new Map();
            this.map.set(target, paramMap);
        }
        let paramIndexes: any[] | undefined = paramMap.get(methodName);
        if (!paramIndexes) {
            paramIndexes = [];
            paramMap.set(methodName, paramIndexes);
        }
        paramIndexes.push({ index: paramIndex, handler: handler });
    }

    public static async inject(target: any, methodName: string, args: any[]): Promise<any[]> {
        let paramMap: Map<string, number[]> | undefined = this.map.get(target);
        if (!paramMap) {
            return [];
        }
        let paramIndexes: any[] | undefined = paramMap.get(methodName);
        if (!paramIndexes) {
            return [];
        }

        let paramValues : any [] = []
        for (const [index, paramValue] of paramIndexes.entries()) {
            const pi = paramIndexes[index];
            const value : any = await pi.handler();
            paramValues.push([index, value]);
        }
        return paramValues;
    }
}