package proxy_test

import (
	"net/http"
	"strings"
	"sync"
	"testing"
	"time"

	"git.wntrmute.dev/kyle/crossbar/internal/store"
)

// A response the proxy delivered in full is recorded with the status the upstream returned, even
// when the client closes its connection the instant the body ends. Cancellation is what the
// reverse proxy observed while forwarding (a transport error before any byte, or the client
// leaving mid-body), never a look at the request context after the forward returned.
//
// Each request uses its own connection and closes it as soon as the response is read, which is
// what a pooled client does when its idle pool is full; the server then cancels the request's
// context while the handler may still be writing the accounting row.
func TestServedResponseIsNeverRecordedCancelled(t *testing.T) {
	alpha := newUpstream(t, "alpha")
	alpha.delay = 20 * time.Millisecond
	r := newRig(t, `
listen = "127.0.0.1:1"
queue_max = 64
[hosts.alpha]
base_url = %q
models = { "shared" = { parallel = 8 } }
[routes.r]
hosts = ["alpha"]
default_model = "shared"
`, alpha)

	const n = 32
	var wg sync.WaitGroup
	codes := make([]int, n)
	for i := 0; i < n; i++ {
		wg.Add(1)
		go func(i int) {
			defer wg.Done()
			client := &http.Client{Transport: &http.Transport{DisableKeepAlives: true}}
			req, _ := http.NewRequest(http.MethodPost, r.front.URL+"/r/v1/chat/completions", strings.NewReader(conversation(i, 1)))
			req.Header.Set("Content-Type", "application/json")
			resp, err := client.Do(req)
			if err != nil {
				t.Error(err)
				return
			}
			drain(resp)
			codes[i] = resp.StatusCode
		}(i)
	}
	wg.Wait()
	for i, c := range codes {
		if c != 200 {
			t.Fatalf("request %d: status %d, want 200", i, c)
		}
	}

	// Rows are written after each response completes; allow the store a moment to catch up.
	var rows []store.UsageRow
	deadline := time.Now().Add(3 * time.Second)
	for time.Now().Before(deadline) {
		rows, _ = r.store.Usage(time.Time{}, store.ByRoute)
		if len(rows) == 1 && rows[0].Requests == n {
			break
		}
		time.Sleep(20 * time.Millisecond)
	}
	if len(rows) != 1 || rows[0].Requests != n {
		t.Fatalf("usage = %+v, want one row with %d requests", rows, n)
	}
	if rows[0].Errors != 0 {
		t.Errorf("usage = %+v, want 0 errors: every response was delivered with status 200", rows[0])
	}
	counts, _ := r.store.StatusCounts(time.Time{})
	for _, c := range counts {
		if c.Status != 200 {
			t.Errorf("status counts %+v: a delivered 200 was recorded as %d", counts, c.Status)
		}
	}
}