Give each event its own page and show bodies the same everywhere (closes #369)

Each row of the recent events on the webhook page links to the
event's own page, /hook/{id}/events/{eventID}, and expands to show its
body; only the newest starts expanded. The event's page shows its
details, its whole body and every delivery with its attempts.

One renderer, newBodyView with templates/event_body.html, shows a body
in all three places: whole up to 32 KiB, cut there in the lists with a
link to the event's page, JSON pretty-printed, a body of more than 200
lines or 32 KiB in a scrolling box, and a body that is not text left
out beside its download link. A resubmitted copy links to its
original's page.

Model: opus-5-5

internal/handlers/recent_events_test.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net/http"
 	"net/http/httptest"
+	"strconv"
 	"strings"
 	"testing"
 	"time"
@@ -301,6 +302,73 @@ func TestHandleSourceDetail_NoStatusWithoutSingleHTTPTarget(
 	}
 }
 
+// TestHandleSourceDetail_RecentEventsLinkAndExpand proves each row
+// links to its event's own page and expands to show its body, and
+// that only the newest row starts expanded.
+func TestHandleSourceDetail_RecentEventsLinkAndExpand(t *testing.T) {
+	t.Parallel()
+
+	f := newRecentEventsFixture(t)
+	now := time.Now()
+
+	older := f.event(
+		t, contentTypeJSON, `{"which":"older"}`, now.Add(-time.Minute),
+	)
+	newer := f.event(t, contentTypeJSON, `{"which":"newer"}`, now)
+
+	body := f.render(t)
+
+	for _, e := range []*database.Event{older, newer} {
+		assert.Contains(
+			t, body, `href="/hook/`+f.webhook.ID+`/events/`+e.ID+`"`,
+		)
+	}
+
+	assert.Equal(t, 2, strings.Count(body, `<div x-show="open" x-cloak class="mt-3">`))
+	assert.Equal(t, 1, strings.Count(body, " data-open>"))
+
+	open := strings.Index(body, " data-open>")
+	newerBody := strings.Index(body, "&#34;which&#34;: &#34;newer&#34;")
+	olderBody := strings.Index(body, "&#34;which&#34;: &#34;older&#34;")
+
+	assert.Less(t, open, newerBody, "the newest row is not the open one")
+	assert.Less(t, newerBody, olderBody)
+}
+
+// TestHandleSourceDetail_RecentEventBodyCut proves a body up to
+// the cap is shown whole and pretty-printed, and a larger one only
+// its first bodyCap bytes, as received, with links to the whole
+// body on the event's page and to the download.
+func TestHandleSourceDetail_RecentEventBodyCut(t *testing.T) {
+	t.Parallel()
+
+	f := newRecentEventsFixture(t)
+	now := time.Now()
+
+	// A JSON document of n bytes.
+	document := func(n int) string {
+		return `{"pad":"` + strings.Repeat("x", n-len(`{"pad":""}`)) + `"}`
+	}
+
+	whole := f.event(
+		t, contentTypeJSON, document(bodyCap), now.Add(-time.Minute),
+	)
+	cut := f.event(t, contentTypeJSON, document(bodyCap+1), now)
+
+	body := f.render(t)
+	eventURL := `href="/hook/` + f.webhook.ID + `/events/`
+
+	assert.Equal(t, 1, strings.Count(body, "{\n  &#34;pad&#34;: "))
+	assert.Contains(t, body, "{&#34;pad&#34;:&#34;xxx")
+	assert.Contains(
+		t, body,
+		"Showing the first "+strconv.Itoa(bodyCap)+" of "+
+			strconv.Itoa(bodyCap+1)+" bytes, unformatted.",
+	)
+	assert.Contains(t, body, eventURL+cut.ID+`/body"`)
+	assert.NotContains(t, body, eventURL+whole.ID+`/body"`)
+}
+
 // TestHandleWebhook_RecordsBodySize proves the receiver records the
 // body's size in bytes, not characters, with the event it stores.
 func TestHandleWebhook_RecordsBodySize(t *testing.T) {