Grow journal: time-stamped notes on gardens, beds and plantings (#52)

"Take notes through the season on each bed and plant." There is already
free-text notes on gardens, objects and plants, but it is a single mutable
field: writing "powdery mildew on the west bed" overwrites what you wrote in
June. The distinction worth keeping is that notes says what this thing IS, while
a journal entry says what HAPPENED, and when. Both stay.

garden_id is NOT NULL even when an entry is about a bed or a single plop, and
that is the whole trick: permission checks reuse requireGardenRole unchanged and
no second ACL path is invented. object_id/planting_id narrow the target; the
garden always anchors it. Because the garden anchors permission, the target is
checked to actually live in that garden — otherwise a valid object id from
someone else's garden would be storable here and then leak through the list
read. A plop-level entry that also names an object must name the right one, or
the two filters would disagree about what an entry is about.

observed_at is distinct from created_at: you write up Saturday's observations on
Sunday, and Saturday is the date that matters. Listing orders by observation,
newest first, with id breaking ties inside a day.

Roles follow the existing shape. Editors write, viewers read, strangers get
ErrNotFound. An author may edit their own entries; the garden owner may DELETE
any entry in their garden but may not edit one — rewriting somebody else's
observation under their name is a different act from removing it.

Deliberately not wired into the revision history, per the decision on #52:
entries are already append-shaped and individually versioned, and undoing a note
is just deleting it. There's a test asserting journal writes produce no change
sets, so that decision can't quietly reverse itself later.

Closes #52

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01H3zbym8Doka2d7D48maSgZ

internal/api/journal.go

@@ -0,0 +1,142 @@
+package api
+
+import (
+	"errors"
+	"net/http"
+	"strconv"
+
+	"github.com/gin-gonic/gin"
+
+	"gitea.stevedudenhoeffer.com/steve/pansy/internal/domain"
+	"gitea.stevedudenhoeffer.com/steve/pansy/internal/service"
+)
+
+// Grow journal (#52). Entries hang off a garden even when they're about one bed
+// or one plop, which is what lets the permission check be the ordinary garden
+// role check with nothing new invented.
+
+// journalResponse is the body of GET /gardens/:id/journal.
+type journalResponse struct {
+	Entries []domain.JournalEntry `json:"entries"`
+	HasMore bool                  `json:"hasMore"`
+}
+
+// journalCreateRequest is the body for POST /gardens/:id/journal. observedAt
+// defaults to today when omitted — the common case is writing about now.
+type journalCreateRequest struct {
+	ObjectID   *int64  `json:"objectId"`
+	PlantingID *int64  `json:"plantingId"`
+	Body       string  `json:"body" binding:"required"`
+	ObservedAt *string `json:"observedAt"`
+}
+
+// journalUpdateRequest is the body for PATCH /journal/:id. Only the text and the
+// date it describes are editable; an entry's target and author are fixed.
+type journalUpdateRequest struct {
+	Body       *string `json:"body"`
+	ObservedAt *string `json:"observedAt"`
+	Version    int64   `json:"version" binding:"required"`
+}
+
+func (h *handlers) listJournal(c *gin.Context) {
+	gardenID, ok := parseIDParam(c, "id")
+	if !ok {
+		return
+	}
+	q := service.JournalQuery{
+		Limit:  intQuery(c, "limit", 0),
+		Offset: intQuery(c, "offset", 0),
+	}
+	var err error
+	if q.ObjectID, err = optionalIDQuery(c, "objectId"); err != nil {
+		writeAPIError(c, http.StatusBadRequest, "INVALID_INPUT", "invalid objectId")
+		return
+	}
+	if q.PlantingID, err = optionalIDQuery(c, "plantingId"); err != nil {
+		writeAPIError(c, http.StatusBadRequest, "INVALID_INPUT", "invalid plantingId")
+		return
+	}
+	if from := c.Query("from"); from != "" {
+		q.From = &from
+	}
+	if to := c.Query("to"); to != "" {
+		q.To = &to
+	}
+
+	entries, hasMore, err := h.svc.ListJournal(c.Request.Context(), mustActor(c).ID, gardenID, q)
+	if err != nil {
+		writeServiceError(c, err)
+		return
+	}
+	c.JSON(http.StatusOK, journalResponse{Entries: entries, HasMore: hasMore})
+}
+
+func (h *handlers) createJournalEntry(c *gin.Context) {
+	gardenID, ok := parseIDParam(c, "id")
+	if !ok {
+		return
+	}
+	var req journalCreateRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		writeAPIError(c, http.StatusBadRequest, "INVALID_INPUT", "invalid entry: a body is required")
+		return
+	}
+	e, err := h.svc.CreateJournalEntry(c.Request.Context(), mustActor(c).ID, gardenID, service.JournalInput{
+		ObjectID: req.ObjectID, PlantingID: req.PlantingID, Body: req.Body, ObservedAt: req.ObservedAt,
+	})
+	if err != nil {
+		writeServiceError(c, err)
+		return
+	}
+	c.JSON(http.StatusCreated, e)
+}
+
+func (h *handlers) updateJournalEntry(c *gin.Context) {
+	id, ok := parseIDParam(c, "id")
+	if !ok {
+		return
+	}
+	var req journalUpdateRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		writeAPIError(c, http.StatusBadRequest, "INVALID_INPUT", "invalid update: a current version is required")
+		return
+	}
+	e, err := h.svc.UpdateJournalEntry(c.Request.Context(), mustActor(c).ID, id,
+		service.JournalPatch{Body: req.Body, ObservedAt: req.ObservedAt}, req.Version)
+	if err != nil {
+		if errors.Is(err, domain.ErrVersionConflict) {
+			writeVersionConflict(c, e)
+			return
+		}
+		writeServiceError(c, err)
+		return
+	}
+	c.JSON(http.StatusOK, e)
+}
+
+func (h *handlers) deleteJournalEntry(c *gin.Context) {
+	id, ok := parseIDParam(c, "id")
+	if !ok {
+		return
+	}
+	if err := h.svc.DeleteJournalEntry(c.Request.Context(), mustActor(c).ID, id); err != nil {
+		writeServiceError(c, err)
+		return
+	}
+	c.Status(http.StatusNoContent)
+}
+
+// optionalIDQuery reads a positive int64 query parameter, or nil when absent.
+// A present-but-malformed value is an error rather than a silent nil, so a typo
+// doesn't quietly widen a filter to the whole garden.
+func optionalIDQuery(c *gin.Context, name string) (*int64, error) {
+	raw := c.Query(name)
+	if raw == "" {
+		return nil, nil
+	}
+	id, err := strconv.ParseInt(raw, 10, 64)
+	if err != nil || id < 1 {
+		return nil, errors.New("invalid id")
+	}
+	return &id, nil
+}