| 1 | package calendar |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "embed" |
| 6 | "errors" |
| 7 | "fmt" |
| 8 | "strings" |
| 9 | "text/template" |
| 10 | "time" |
| 11 | ) |
| 12 | |
| 13 | // Booking mail (booking spec §6): four kinds, plain text, rendered at |
| 14 | // send time from the booking's CURRENT state and the public view — |
| 15 | // nothing a booker may not see reaches a template here. |
| 16 | |
| 17 | //go:embed templates/mail/*.txt |
| 18 | var mailFS embed.FS |
| 19 | |
| 20 | var mailTemplates = template.Must(template.ParseFS(mailFS, "templates/mail/*.txt")) |
| 21 | |
| 22 | // mailData is what every mail template receives. |
| 23 | type mailData struct { |
| 24 | publicBooking |
| 25 | ManageURL string |
| 26 | EventURL string |
| 27 | // Note is the booker's note, for HOST mail only: the host is on the |
| 28 | // team and this is delivery (spec §6). Never set on a booker's mail. |
| 29 | Note string |
| 30 | // Stale is set on a "confirmed" mail whose booking is no longer |
| 31 | // confirmed when it finally renders, so the first line says so |
| 32 | // rather than announcing a meeting that was since cancelled (B19). |
| 33 | Stale bool |
| 34 | } |
| 35 | |
| 36 | // renderBookingMail produces the subject and body for one queue row. |
| 37 | func (h *handlers) renderBookingMail(row BookingMail, v BookingView, now time.Time) (to, subject, body string, err error) { |
| 38 | pb := publicOf(v, now) |
| 39 | d := mailData{publicBooking: pb, EventURL: h.eventURL(v.EventID)} |
| 40 | if v.Token != "" { |
| 41 | d.ManageURL = h.manageURL(v.Token) |
| 42 | } |
| 43 | if row.Recipient == ToHost { |
| 44 | to = v.Host.Address |
| 45 | d.Note = v.Note |
| 46 | } else { |
| 47 | to = v.Address |
| 48 | } |
| 49 | switch row.Kind { |
| 50 | case MailHold: |
| 51 | subject = "Confirm your booking: " + pb.Title |
| 52 | case MailConfirmed: |
| 53 | subject = pb.Name + " booked " + pb.Title |
| 54 | d.Stale = !pb.Live |
| 55 | case MailRescheduled: |
| 56 | subject = "Moved: " + pb.Title |
| 57 | case MailCancelled: |
| 58 | subject = "Cancelled: " + pb.Title |
| 59 | default: |
| 60 | return "", "", "", fmt.Errorf("calendar: unknown mail kind") |
| 61 | } |
| 62 | name := row.Kind + "_" + row.Recipient + ".txt" |
| 63 | if t := mailTemplates.Lookup(name); t == nil { |
| 64 | name = row.Kind + ".txt" |
| 65 | } |
| 66 | var b strings.Builder |
| 67 | if err := mailTemplates.ExecuteTemplate(&b, name, d); err != nil { |
| 68 | return "", "", "", fmt.Errorf("calendar: render mail %s: %w", row.Kind, err) |
| 69 | } |
| 70 | return to, subject, b.String(), nil |
| 71 | } |
| 72 | |
| 73 | // sendBookingMail delivers one claimed row and records the outcome: |
| 74 | // acknowledged, deferred (the sender was busy — no attempt), or failed. |
| 75 | // Nothing is concluded from an error except "try again later" (B16). |
| 76 | func (h *handlers) sendBookingMail(ctx context.Context, row BookingMail, now time.Time) error { |
| 77 | v, err := h.store.BookingByID(ctx, row.BookingID, true) |
| 78 | if err != nil { |
| 79 | return err |
| 80 | } |
| 81 | // A row the booking's CURRENT state makes meaningless is retired |
| 82 | // unsent (B19): a hold mail after the hold was confirmed or |
| 83 | // expired, a rescheduled mail after a cancellation. Mail says the |
| 84 | // current state or says nothing. |
| 85 | if obsolete(row, v, now) { |
| 86 | if _, err := h.store.MarkBookingMailSent(keep(ctx), row.ID, row.ClaimID, now.Unix()); err != nil { |
| 87 | return err |
| 88 | } |
| 89 | return errMailRetired |
| 90 | } |
| 91 | to, subject, body, err := h.renderBookingMail(row, v, now) |
| 92 | if err != nil { |
| 93 | return err |
| 94 | } |
| 95 | sendCtx, cancel := context.WithTimeout(ctx, maxSendWait) |
| 96 | defer cancel() |
| 97 | err = h.mailer.Send(sendCtx, to, subject, body) |
| 98 | switch { |
| 99 | case err == nil: |
| 100 | ok, err := h.store.MarkBookingMailSent(keep(ctx), row.ID, row.ClaimID, now.Unix()) |
| 101 | if err == nil && !ok { |
| 102 | return errClaimLost |
| 103 | } |
| 104 | return err |
| 105 | case errors.Is(err, ErrMailBusy): |
| 106 | if _, err := h.store.DeferBookingMail(keep(ctx), row.ID, row.ClaimID, now.Unix()); err != nil { |
| 107 | return err |
| 108 | } |
| 109 | return errMailDeferred |
| 110 | default: |
| 111 | gaveUp, merr := h.store.MarkBookingMailFailed(keep(ctx), row.ID, row.ClaimID) |
| 112 | if merr != nil { |
| 113 | return merr |
| 114 | } |
| 115 | code := "retry" |
| 116 | if gaveUp { |
| 117 | code = "gave_up" |
| 118 | } |
| 119 | // No address, no token, no title, and NOT the sender's text — |
| 120 | // it quotes the subject when it refuses a header: a stage and |
| 121 | // two codes. |
| 122 | h.logger.Error("calendar: booking mail", "stage", "booking.mail", "code", code, "why", mailCode(err)) |
| 123 | return err |
| 124 | } |
| 125 | } |
| 126 | |
| 127 | // The two outcomes that are neither a send nor a failure. Both are |
| 128 | // errors to the caller so a deferral is never counted as delivery and a |
| 129 | // hold page never says "sent" about a row that went back in the queue. |
| 130 | var ( |
| 131 | errMailDeferred = errors.New("calendar: mail deferred") |
| 132 | errMailRetired = errors.New("calendar: mail retired unsent") |
| 133 | ) |
| 134 | |
| 135 | // obsolete says whether a queued row has been overtaken by the state |
| 136 | // it would describe. |
| 137 | func obsolete(row BookingMail, v BookingView, now time.Time) bool { |
| 138 | switch row.Kind { |
| 139 | case MailHold: |
| 140 | return v.State != BookingHeld || now.Unix() >= v.HoldExpiresAt |
| 141 | case MailRescheduled: |
| 142 | return v.Cancelled() |
| 143 | } |
| 144 | return false |
| 145 | } |
| 146 | |
| 147 | // trySendNow is the immediate attempt after a transition: claim and |
| 148 | // send THIS booking's owed rows, once each, inside a bounded budget. |
| 149 | // Everybody else's mail is the drain's; a stranger's POST must not wait |
| 150 | // through it. Failures are the drain's to retry; the caller learns only |
| 151 | // whether everything went. |
| 152 | func (h *handlers) trySendNow(ctx context.Context, bookingID int64, now time.Time) (allSent bool) { |
| 153 | ctx, cancel := context.WithTimeout(ctx, 2*maxSendWait) |
| 154 | defer cancel() |
| 155 | sctx, scancel := sendBudget(ctx) |
| 156 | defer scancel() |
| 157 | for i := 0; i < 4; i++ { |
| 158 | row, ok, err := h.store.ClaimBookingMailFor(ctx, bookingID, now.Unix()) |
| 159 | if err != nil { |
| 160 | return false |
| 161 | } |
| 162 | if !ok { |
| 163 | break |
| 164 | } |
| 165 | _ = h.sendBookingMail(sctx, row, now) |
| 166 | } |
| 167 | // Nothing claimable is not everything sent: a row another worker |
| 168 | // holds a lease on, or one this loop deferred, is still owed. The |
| 169 | // page says "sent" only when the booking owes nothing. |
| 170 | owes, err := h.store.OwesMail(keep(ctx), bookingID) |
| 171 | return err == nil && !owes |
| 172 | } |
| 173 | |
amadan