package main

import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"

	"git.tuxpa.in/a/lambda"
	"git.tuxpa.in/a/lambda/parallel"
)

type RequestContext[T any] struct {
	req http.Request
	ans T
	err error
}

func (r *RequestContext[T]) String() string {
	return fmt.Sprintf("%+v", r.ans)
}

func (_ *RequestContext[T]) Do() func(r *RequestContext[T]) *RequestContext[T] {
	return func(r *RequestContext[T]) *RequestContext[T] {
		r.ans = *new(T)
		res, err := http.DefaultClient.Do(&r.req)
		if err != nil {
			r.err = err
			return r
		}
		defer res.Body.Close()
		r.err = json.NewDecoder(res.Body).Decode(&r.ans)
		return r
	}
}

type someResult struct {
	Title string `json:"title"`
	Id    int    `json:"id"`
}

func main() {
	var requests = make([]*RequestContext[someResult], 20)
	for i := range requests {
		r, _ := http.NewRequest("GET", fmt.Sprintf("https://jsonplaceholder.typicode.com/todos/%d", i+1), nil)
		requests[i] = &RequestContext[someResult]{
			req: *r,
		}
	}
	results := lambda.Filter(parallel.Map(requests, requests[0].Do(), 4), func(r *RequestContext[someResult]) bool {
		return r.err == nil
	})
	for _, v := range results {
		log.Printf("%s", v)
	}
}