| 1 | package bot |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "encoding/json" |
| 6 | "fmt" |
| 7 | "net/http" |
| 8 | "net/url" |
| 9 | "os" |
| 10 | "strings" |
| 11 | "time" |
| 12 | |
| 13 | "lchat/internal/e2ee" |
| 14 | ) |
| 15 | |
| 16 | // Announcer is the engine behind a recipe's `changelog` rule |
| 17 | // (docs/bot-recipes.md): it polls the instance's embedded changelog |
| 18 | // (/api/changelog) and posts entries it hasn't announced yet into every |
| 19 | // group/DM the bot has been added to. It powered the retired default |
| 20 | // "Announcer" identity; today the app announces its own updates server-side |
| 21 | // (announce.go — a push to admins + the Admin app's update stream), and this |
| 22 | // engine stays for operators whose custom bots explicitly opt into posting |
| 23 | // release notes to groups. |
| 24 | // |
| 25 | // Deliberately write-only: it never fetches or decrypts a single message — it |
| 26 | // unwraps thread keys only to *encrypt* what it posts, and it calls no model |
| 27 | // API. "This bot is in the group" means "it can post here", not "it reads |
| 28 | // this room". |
| 29 | // |
| 30 | // State (which entries have been announced) lives at <session>.state.json |
| 31 | // ({"announced":[ids]}), so a restart never replays entries. |
| 32 | type Announcer struct { |
| 33 | Base string |
| 34 | Session *Session |
| 35 | // StatePath defaults to <session path>.state.json via StatePathFor. |
| 36 | StatePath string |
| 37 | // Logf receives progress lines ("announced 2 entries to 3/3 threads"). |
| 38 | Logf func(format string, args ...any) |
| 39 | |
| 40 | client *http.Client |
| 41 | kindDeclared bool |
| 42 | } |
| 43 | |
| 44 | // StatePathFor mirrors the Node announcer's convention. |
| 45 | func StatePathFor(sessionPath string) string { return sessionPath + ".state.json" } |
| 46 | |
| 47 | type announcerState struct { |
| 48 | Announced []string `json:"announced"` |
| 49 | } |
| 50 | |
| 51 | // Tick runs one poll: declare our kind (once, best-effort), fetch the |
| 52 | // changelog, and post anything new to every thread we're in. On the very first |
| 53 | // run it baselines to the current changelog without posting, so a fresh |
| 54 | // announcer announces what ships *after* it, not history. |
| 55 | func (a *Announcer) Tick() error { |
| 56 | if a.client == nil { |
| 57 | // Marked like all sidecar-to-instance traffic (sidecarmark.go), so a |
| 58 | // recipe's announce poller can't hold a hibernating instance awake. |
| 59 | a.client = &http.Client{Timeout: 30 * time.Second, Transport: markTransport{}} |
| 60 | } |
| 61 | a.declareKind() |
| 62 | |
| 63 | var cl struct { |
| 64 | Entries []struct { |
| 65 | ID string `json:"id"` |
| 66 | Text string `json:"text"` |
| 67 | } `json:"entries"` |
| 68 | } |
| 69 | if err := a.get("/api/changelog", &cl); err != nil { |
| 70 | return fmt.Errorf("changelog: %w", err) |
| 71 | } |
| 72 | |
| 73 | raw, err := os.ReadFile(a.StatePath) |
| 74 | if os.IsNotExist(err) { |
| 75 | ids := make([]string, 0, len(cl.Entries)) |
| 76 | for _, e := range cl.Entries { |
| 77 | ids = append(ids, e.ID) |
| 78 | } |
| 79 | a.logf("baselined at %d entries", len(ids)) |
| 80 | return a.saveState(announcerState{Announced: ids}) |
| 81 | } |
| 82 | if err != nil { |
| 83 | return err |
| 84 | } |
| 85 | var state announcerState |
| 86 | if err := json.Unmarshal(raw, &state); err != nil { |
| 87 | return fmt.Errorf("bad state file %s: %w", a.StatePath, err) |
| 88 | } |
| 89 | seen := make(map[string]bool, len(state.Announced)) |
| 90 | for _, id := range state.Announced { |
| 91 | seen[id] = true |
| 92 | } |
| 93 | var fresh []string // entry texts, oldest first (changelog order) |
| 94 | for _, e := range cl.Entries { |
| 95 | if e.ID != "" && e.Text != "" && !seen[e.ID] { |
| 96 | fresh = append(fresh, e.Text) |
| 97 | state.Announced = append(state.Announced, e.ID) |
| 98 | } |
| 99 | } |
| 100 | if len(fresh) == 0 { |
| 101 | return nil |
| 102 | } |
| 103 | |
| 104 | text := "🚀 Just shipped:\n\n" + strings.Join(fresh, "\n\n") |
| 105 | var tl struct { |
| 106 | Threads []struct { |
| 107 | ID string `json:"id"` |
| 108 | Kind string `json:"kind"` |
| 109 | Wrapped string `json:"wrapped"` |
| 110 | } `json:"threads"` |
| 111 | } |
| 112 | if err := a.get("/api/threads", &tl); err != nil { |
| 113 | return fmt.Errorf("threads: %w", err) |
| 114 | } |
| 115 | posted, targets := 0, 0 |
| 116 | for _, t := range tl.Threads { |
| 117 | if t.Wrapped == "" || (t.Kind != "group" && t.Kind != "dm") { |
| 118 | continue |
| 119 | } |
| 120 | targets++ |
| 121 | if err := a.post(t.ID, t.Wrapped, text); err != nil { |
| 122 | a.logf("thread %s: %v", t.ID, err) |
| 123 | continue |
| 124 | } |
| 125 | posted++ |
| 126 | } |
| 127 | // Mark announced even with zero targets: entries shipped while the bot sat |
| 128 | // in no groups are old news by the time someone adds it — don't replay them. |
| 129 | if err := a.saveState(state); err != nil { |
| 130 | return err |
| 131 | } |
| 132 | a.logf("announced %d entries to %d/%d threads", len(fresh), posted, targets) |
| 133 | return nil |
| 134 | } |
| 135 | |
| 136 | // Run is the poll loop, until ctx is cancelled. Tick errors are logged and |
| 137 | // retried next tick. |
| 138 | func (a *Announcer) Run(ctx context.Context, interval time.Duration) { |
| 139 | for { |
| 140 | if err := a.Tick(); err != nil { |
| 141 | a.logf("tick failed: %v", err) |
| 142 | } |
| 143 | select { |
| 144 | case <-time.After(interval): |
| 145 | case <-ctx.Done(): |
| 146 | return |
| 147 | } |
| 148 | } |
| 149 | } |
| 150 | |
| 151 | // post encrypts one message under the thread's key and posts it — the only |
| 152 | // thing the announcer ever does with a thread key. |
| 153 | func (a *Announcer) post(threadID, wrapped, text string) error { |
| 154 | keyB64, err := e2ee.UnwrapThreadKey(wrapped, a.Session.UserPriv) |
| 155 | if err != nil { |
| 156 | return err |
| 157 | } |
| 158 | key, err := e2ee.ImportKey(keyB64) |
| 159 | if err != nil { |
| 160 | return err |
| 161 | } |
| 162 | blob, err := e2ee.EncryptJSON(key, map[string]any{ |
| 163 | "name": a.Session.Name, "text": text, "ts": time.Now().UnixMilli(), |
| 164 | }) |
| 165 | if err != nil { |
| 166 | return err |
| 167 | } |
| 168 | body, _ := json.Marshal(map[string]string{"thread_id": threadID, "blob": blob}) |
| 169 | resp, err := a.client.Post(a.Base+"/api/messages?token="+url.QueryEscape(a.Session.Token), |
| 170 | "application/json", strings.NewReader(string(body))) |
| 171 | if err != nil { |
| 172 | return err |
| 173 | } |
| 174 | defer resp.Body.Close() |
| 175 | if resp.StatusCode != http.StatusOK { |
| 176 | return fmt.Errorf("server %d", resp.StatusCode) |
| 177 | } |
| 178 | return nil |
| 179 | } |
| 180 | |
| 181 | // declareKind self-reports "bot" (deterministic — no model) so the UI badges |
| 182 | // us BOT, not AI. Best-effort; retried on a later tick if it fails. |
| 183 | func (a *Announcer) declareKind() { |
| 184 | if a.kindDeclared { |
| 185 | return |
| 186 | } |
| 187 | body, _ := json.Marshal(map[string]string{"token": a.Session.Token, "kind": "bot"}) |
| 188 | resp, err := a.client.Post(a.Base+"/api/bot-config", "application/json", strings.NewReader(string(body))) |
| 189 | if err != nil { |
| 190 | a.logf("declare kind: %v", err) |
| 191 | return |
| 192 | } |
| 193 | resp.Body.Close() |
| 194 | a.kindDeclared = resp.StatusCode == http.StatusOK |
| 195 | } |
| 196 | |
| 197 | func (a *Announcer) get(path string, out any) error { |
| 198 | resp, err := a.client.Get(a.Base + path + "?token=" + url.QueryEscape(a.Session.Token)) |
| 199 | if err != nil { |
| 200 | return err |
| 201 | } |
| 202 | defer resp.Body.Close() |
| 203 | if resp.StatusCode != http.StatusOK { |
| 204 | return fmt.Errorf("%s: server %d", path, resp.StatusCode) |
| 205 | } |
| 206 | return json.NewDecoder(resp.Body).Decode(out) |
| 207 | } |
| 208 | |
| 209 | func (a *Announcer) saveState(s announcerState) error { |
| 210 | raw, err := json.Marshal(s) |
| 211 | if err != nil { |
| 212 | return err |
| 213 | } |
| 214 | return os.WriteFile(a.StatePath, raw, 0o600) |
| 215 | } |
| 216 | |
| 217 | func (a *Announcer) logf(format string, args ...any) { |
| 218 | if a.Logf != nil { |
| 219 | a.Logf("announcer: "+format, args...) |
| 220 | } |
| 221 | } |
| 222 | |
amadan