HTTP API: a chat's recent messages, and sending a message (closes #5)

`GET /api/v1/chats/{id}/messages?count=N` returns a chat's recent messages, oldest first (`count` 1 to 100, default 20), and `POST` to the same path sends a text message and returns it once the chat client has taken it. Both answer `404` for any id the chats list does not show, looked up in the same contact list. The message record is defined once, for the webhooks to reuse.

Disclosures: items are read five at a time, because one item can be many times its text and 100 at once could pass the 16 MiB read limit; text too long gets `413`, a contact who deleted the chat `409` (unverified for one still connecting); a query the server cannot read gets its own `400`.

Model: opus-5-5

internal/simplex/messages_test.go

@@ -0,0 +1,214 @@
+package simplex_test
+
+import (
+	"errors"
+	"slices"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+
+	"sneak.berlin/go/simplexcalc/internal/simplex"
+)
+
+// Chat items as simplex-chat v7.0.2 sends them, oldest first: an event it
+// records in a chat, the greeting the bot sent, a text, a formatted text
+// and a picture a contact sent, and a text the bot sent.
+const (
+	itemEvent = `{"chatDir":{"type":"directRcv"},"meta":{"itemId":7,
+		"itemTs":"2026-09-29T03:13:46.521359978Z",
+		"itemText":"Audio/video calls: enabled","itemStatus":{"type":"rcvRead"},
+		"createdAt":"2026-09-29T03:13:46.521359978Z"},
+		"content":{"type":"rcvChatFeature","feature":"calls",
+		"enabled":{"forUser":true,"forContact":true}},"mentions":{},"reactions":[]}`
+
+	itemGreeting = `{"chatDir":{"type":"directSnd"},"meta":{"itemId":8,
+		"itemTs":"2026-09-29T03:13:46.925072391Z","itemText":"hi",
+		"itemStatus":{"type":"sndRcvd","msgRcptStatus":"ok","sndProgress":"complete"},
+		"createdAt":"2026-09-29T03:13:46.925072391Z"},
+		"content":{"type":"sndMsgContent","msgContent":{"type":"text","text":"hi"}},
+		"mentions":{},"reactions":[]}`
+
+	itemText = `{"chatDir":{"type":"directRcv"},"meta":{"itemId":9,
+		"itemTs":"2026-09-29T03:14:34Z","itemText":"2 + 2",
+		"itemStatus":{"type":"rcvNew"},"itemSharedMsgId":"bCtLTUFwY3NCSFZIR002Ng==",
+		"createdAt":"2026-09-29T03:14:34.865730547Z"},
+		"content":{"type":"rcvMsgContent","msgContent":{"type":"text","text":"2 + 2"}},
+		"mentions":{},"reactions":[]}`
+
+	itemFormatted = `{"chatDir":{"type":"directRcv"},"meta":{"itemId":10,
+		"itemTs":"2026-09-29T03:14:34Z","itemText":"*bold* and _italic_",
+		"itemStatus":{"type":"rcvNew"},"createdAt":"2026-09-29T03:14:34.935833284Z"},
+		"content":{"type":"rcvMsgContent",
+		"msgContent":{"type":"text","text":"*bold* and _italic_"}},"mentions":{},
+		"formattedText":[{"format":{"type":"bold"},"text":"bold"},{"text":" and "},
+		{"format":{"type":"italic"},"text":"italic"}],"reactions":[]}`
+
+	itemPicture = `{"chatDir":{"type":"directRcv"},"meta":{"itemId":11,
+		"itemTs":"2026-09-29T03:14:34Z","itemText":"a picture",
+		"itemStatus":{"type":"rcvNew"},"createdAt":"2026-09-29T03:14:35.020538268Z"},
+		"content":{"type":"rcvMsgContent","msgContent":{"type":"image",
+		"text":"a picture","image":"data:image/jpg;base64,/9j/4AAQSkZJRgABAQ=="}},
+		"mentions":{},"reactions":[]}`
+
+	itemSent = `{"chatDir":{"type":"directSnd"},"meta":{"itemId":12,
+		"itemTs":"2026-09-29T03:14:43.519552587Z","itemText":"hello from the API",
+		"itemStatus":{"type":"sndNew"},"createdAt":"2026-09-29T03:14:43.519552587Z"},
+		"content":{"type":"sndMsgContent",
+		"msgContent":{"type":"text","text":"hello from the API"}},
+		"mentions":{},"reactions":[]}`
+)
+
+// The chat client's answer to /_send, and its refusals: of a contact the
+// bot does not have, of one who has deleted their chat with the bot, and
+// of a text too long for one message.
+const (
+	sentItems = `{"type":"newChatItems","user":{"userId":1},"chatItems":[
+		{"chatInfo":{"type":"direct","contact":{"contactId":3,
+		"localDisplayName":"tester","contactStatus":"active"}},
+		"chatItem":` + itemSent + `}]}`
+
+	contactNotFound = `{"type":"chatCmdError","chatError":{"type":"errorStore",
+		"storeError":{"type":"contactNotFound","contactId":4}}}`
+
+	contactNotReady = `{"type":"chatCmdError","chatError":{"type":"error",
+		"errorType":{"type":"contactNotReady","contact":{"contactId":4,
+		"localDisplayName":"tester_1","contactStatus":"deleted",
+		"activeConn":{"connId":3,"connStatus":{"type":"deleted"}}}}}}`
+
+	largeMsg = `{"type":"chatCmdError","chatError":{"type":"errorStore",
+		"storeError":{"type":"largeMsg"}}}`
+)
+
+// apiChat is the chat client's answer to /_get chat, holding items.
+func apiChat(items ...string) string {
+	return `{"type":"apiChat","user":{"userId":1},"chat":{"chatInfo":{
+		"type":"direct","contact":{"contactId":3,"localDisplayName":"tester",
+		"contactStatus":"active"}},"chatItems":[` + strings.Join(items, ",") + `],
+		"chatStats":{"unreadCount":0,"minUnreadItemId":0,"unreadChat":false}},
+		"navInfo":null}`
+}
+
+// describe sums up a chat item as its id, content type, message if it
+// has one, and time.
+func describe(item simplex.ChatItem) string {
+	s := strconv.FormatInt(item.Meta.ItemID, 10) + " " + item.Content.Type
+
+	if m := item.Content.MsgContent; m != nil {
+		s += " " + m.Type + " " + strconv.Quote(m.Text)
+	}
+
+	return s + " " + item.Meta.ItemTs.Format(time.RFC3339Nano)
+}
+
+// TestChatItems: the chat's last items come back oldest first, read five
+// at a time from the newest backwards, and reading stops at the start
+// of the chat.
+func TestChatItems(t *testing.T) {
+	t.Parallel()
+
+	f, url := newFakeChat(t, map[string]string{
+		"/_get chat @3 count=5": apiChat(
+			itemGreeting, itemText, itemFormatted, itemPicture, itemSent),
+		"/_get chat @3 before=8 count=2": apiChat(itemEvent),
+	})
+	c, ctx := dial(t, url, nil)
+
+	items, err := c.ChatItems(ctx, 3, 7)
+	if err != nil {
+		t.Fatalf("ChatItems: %v", err)
+	}
+
+	for _, want := range []string{
+		"/_get chat @3 count=5",
+		"/_get chat @3 before=8 count=2",
+	} {
+		if got := f.next(t); got != want {
+			t.Errorf("command = %s, want %s", got, want)
+		}
+	}
+
+	want := []string{
+		`7 rcvChatFeature 2026-09-29T03:13:46.521359978Z`,
+		`8 sndMsgContent text "hi" 2026-09-29T03:13:46.925072391Z`,
+		`9 rcvMsgContent text "2 + 2" 2026-09-29T03:14:34Z`,
+		`10 rcvMsgContent text "*bold* and _italic_" 2026-09-29T03:14:34Z`,
+		`11 rcvMsgContent image "a picture" 2026-09-29T03:14:34Z`,
+		`12 sndMsgContent text "hello from the API" 2026-09-29T03:14:43.519552587Z`,
+	}
+
+	got := make([]string, 0, len(items))
+	for _, item := range items {
+		got = append(got, describe(item))
+	}
+
+	if !slices.Equal(got, want) {
+		t.Errorf("ChatItems =\n%s\nwant\n%s",
+			strings.Join(got, "\n"), strings.Join(want, "\n"))
+	}
+}
+
+// TestSendMessage: a text goes out as /_send, and comes back as the chat
+// client recorded it.
+func TestSendMessage(t *testing.T) {
+	t.Parallel()
+
+	f, url := newFakeChat(t, map[string]string{"/_send": sentItems})
+	c, ctx := dial(t, url, nil)
+
+	item, err := c.SendMessage(ctx, 3, "hello from the API")
+	if err != nil {
+		t.Fatalf("SendMessage: %v", err)
+	}
+
+	want := `/_send @3 json [{"msgContent":{"type":"text",` +
+		`"text":"hello from the API"},"mentions":{}}]`
+	if got := f.next(t); got != want {
+		t.Errorf("command = %s\nwant      %s", got, want)
+	}
+
+	wantItem := `12 sndMsgContent text "hello from the API" ` +
+		`2026-09-29T03:14:43.519552587Z`
+	if got := describe(item); got != wantItem {
+		t.Errorf("SendMessage = %s, want %s", got, wantItem)
+	}
+}
+
+// TestRefusals: the chat client's refusals that callers answer for come
+// back as this package's errors, still carrying the chat client's
+// reason.
+func TestRefusals(t *testing.T) {
+	t.Parallel()
+
+	for name, tc := range map[string]struct {
+		record string
+		read   bool // ChatItems rather than SendMessage
+		want   error
+	}{
+		"reading, no such contact": {contactNotFound, true, simplex.ErrNoContact},
+		"sending, no such contact": {contactNotFound, false, simplex.ErrNoContact},
+		"sending, contact deleted": {contactNotReady, false, simplex.ErrContactNotReady},
+		"sending, text too long":   {largeMsg, false, simplex.ErrMessageTooLarge},
+	} {
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			_, url := newFakeChat(t, map[string]string{
+				"/_get": tc.record, "/_send": tc.record,
+			})
+			c, ctx := dial(t, url, nil)
+
+			var err error
+			if tc.read {
+				_, err = c.ChatItems(ctx, 4, 20)
+			} else {
+				_, err = c.SendMessage(ctx, 4, "hi")
+			}
+
+			var cerr *simplex.CommandError
+			if !errors.Is(err, tc.want) || !errors.As(err, &cerr) {
+				t.Errorf("error = %v, want %v with the chat client's reason", err, tc.want)
+			}
+		})
+	}
+}