package gateway

import (
	"strings"
	"testing"
)

// TestUI_ImageRequestSendsJSONBody pins the bug that made the image page
// unusable in production while every DOM assertion still passed.
//
// The page called api(path, {method, body: {...}}). api() is
// `(p, o) => fetch(p, o)` — o is the NATIVE fetch options object, so an object
// in `body` is coerced by fetch into the literal text "[object Object]". The
// gateway's json.Unmarshal rejected it, the response was a bare 400 with
// lat_ms 0, and the page showed an error toast with no image and no usable
// message.
//
// What made this expensive: the pane rendered, the model list had all six
// models, the button enabled itself, the console was clean. Only the WIRE
// format was wrong, and nothing in the DOM shows a wire format.
func TestUI_ImageRequestSendsJSONBody(t *testing.T) {
	body := sendImageSource(t)

	if !strings.Contains(body, "JSON.stringify") {
		t.Error("sendImage() does not JSON.stringify its body — fetch coerces " +
			"the object to the text \"[object Object]\" and the gateway answers " +
			"400 with lat_ms 0")
	}
	if !strings.Contains(body, `"Content-Type": "application/json"`) {
		t.Error("sendImage() does not set Content-Type: application/json; the " +
			"server sees text/plain and may refuse to parse the body")
	}
	// The literal defect, asserted so a later refactor reintroducing it fails
	// here rather than in a browser.
	if strings.Contains(body, "body: size ? {") || strings.Contains(body, "body: { model") {
		t.Error("sendImage() still passes an object literal as the fetch body")
	}
}

// TestUI_PostCallsSendJSONString guards every POST in the file, not just the
// image one. The image page happened to be the only place that used api() with
// an object body, so a check scoped to it would pass while another page had the
// same defect.
func TestUI_PostCallsSendJSONString(t *testing.T) {
	ui := uiSource(t)
	lines := strings.Split(ui, "\n")

	var bad []string
	for i, l := range lines {
		if !strings.Contains(l, `method: "POST"`) {
			continue
		}
		end := i + 8
		if end > len(lines) {
			end = len(lines)
		}
		window := strings.Join(lines[i:end], "\n")
		if !strings.Contains(window, "body:") {
			continue // no body at all: legitimate (a bare trigger)
		}
		if strings.Contains(window, "JSON.stringify") || strings.Contains(window, "FormData") {
			continue
		}
		bad = append(bad, strings.TrimSpace(l))
	}
	if len(bad) > 0 {
		t.Errorf("%d POST call(s) send a non-string body:", len(bad))
		for _, b := range bad {
			if len(b) > 100 {
				b = b[:100]
			}
			t.Errorf("    %s", b)
		}
	}
}

// TestUI_ImagePageReportsServerErrors pins that a failed generation surfaces
// something actionable. The production bug produced a bare "400 Bad Request"
// toast; the requirement is that the gateway's own message reaches the page.
func TestUI_ImagePageReportsServerErrors(t *testing.T) {
	body := sendImageSource(t)

	// api() throws Error(j.error.message) on !r.ok, so appending e.message is
	// what puts the explanation on screen.
	if !strings.Contains(body, "e && e.message") {
		t.Error("sendImage() does not surface the server's error message; a " +
			"failure would show a bare status with no cause")
	}
	// And a success carrying no image must not look like a success.
	if !strings.Contains(body, "imgNoData") {
		t.Error("sendImage() does not warn when the upstream returns no image")
	}
}

// sendImageSource returns the text of sendImage() only, so an assertion cannot
// be satisfied by a string that happens to appear elsewhere in the file.
func sendImageSource(t *testing.T) string {
	t.Helper()
	ui := uiSource(t)
	i := strings.Index(ui, "async function sendImage(")
	if i < 0 {
		t.Fatal("sendImage() not found")
	}
	body := ui[i:]
	if end := strings.Index(body[1:], "\n      function "); end > 0 {
		body = body[:end+1]
	}
	return body
}