import context
import net.http
import time
import x.async as xasync

fn test_net_http_pool_handles_synthetic_requests_with_backpressure() {
    mut pool := xasync.new_pool(workers: 1, queue_size: 1)!
    started := chan bool{cap: 1}
    release := chan bool{cap: 2}
    responses := chan int{cap: 2}
    first_req := http.new_request(.get, '/first', '')
    second_req := http.new_request(.get, '/second', '')
    third_req := http.new_request(.get, '/third', '')

    pool.try_submit(fn [first_req, started, release, responses] (mut ctx context.Context) ! {
        _ = ctx
        started <- true
        _ := <-release
        resp := synthetic_http_response(first_req)!
        responses <- resp.status_code
    })!
    wait_for_http_signal(started, 'first synthetic HTTP job did not start')

    pool.try_submit(fn [second_req, release, responses] (mut ctx context.Context) ! {
        _ = ctx
        _ := <-release
        resp := synthetic_http_response(second_req)!
        responses <- resp.status_code
    })!
    pool.try_submit(fn [third_req] (mut ctx context.Context) ! {
        _ = ctx
        _ = third_req
    }) or {
        assert err.msg() == 'async: pool queue is full'
        release <- true
        release <- true
        pool.close()!
        assert read_http_status(responses) == 200
        assert read_http_status(responses) == 200
        return
    }
    assert false
}

fn synthetic_http_response(req http.Request) !http.Response {
    if req.url == '' {
        return error('empty synthetic HTTP URL')
    }
    return http.new_response(status: .ok, body: req.url)
}

fn wait_for_http_signal(signal chan bool, message string) {
    select {
        ok := <-signal {
            assert ok
        }
        1 * time.second {
            assert false, message
        }
    }
}

fn read_http_status(responses chan int) int {
    select {
        status := <-responses {
            return status
        }
        1 * time.second {
            assert false, 'synthetic HTTP response was not produced'
        }
    }
    return 0
}