refactor: dedup admin entity handlers and server construction

1 files changed, 343 insertions, 0 deletions

diff --git a/internal/admin/api_entity.go b/internal/admin/api_entity.go
new file mode 100644
index 0000000..b32ab89
--- /dev/null
+++ b/internal/admin/api_entity.go
@@ -0,0 +1,343 @@
+package admin
+
+import (
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// The editor exposes the same list/get/create/update/delete contract for
+// several YAML families. entityCRUD captures everything that actually
+// differed between the hand-written copies; the handlers below are shared by
+// every family.
+//
+// Two wire styles predate this file and must be preserved (see failJSON's
+// contract comment):
+//
+//   - status style (items, drops, mobs, objects, hazards): errors are HTTP
+//     error statuses with a JSON body; a successful write echoes the entity
+//     map (including _raw).
+//   - body style (techs, modules): errors are a 200 JSON body read as
+//     res.error; writes reply {"ok":true,"id":id}. These editors also upsert
+//     (POST/PUT by id creates an absent file).
+type entityCRUD struct {
+	route         string // URL segment and data subdirectory, e.g. "items"
+	noun          string // singular for error text and undo descriptions
+	searchSubdirs bool   // look the entity up in nested directories too
+	upsert        bool   // by-ID POST/PUT creates an absent file
+	bodyErr       bool   // write errors as a 200 JSON body (failJSON)
+	okResponse    bool   // reply {"ok":true,"id":id} and "Created/Updated"
+	refresh       func(*AdminServer)
+}
+
+var (
+	itemSpec = entityCRUD{route: "items", noun: "item", searchSubdirs: true,
+		refresh: func(s *AdminServer) { s.invalidateEntityCaches("items") }}
+	dropSpec = entityCRUD{route: "drops", noun: "drop",
+		refresh: func(s *AdminServer) { s.invalidateEntityCaches("drops") }}
+	mobSpec = entityCRUD{route: "mobs", noun: "mob", searchSubdirs: true,
+		refresh: func(s *AdminServer) { s.invalidateEntityCaches("mobs") }}
+	objectSpec = entityCRUD{route: "objects", noun: "object", searchSubdirs: true}
+	hazardSpec = entityCRUD{route: "hazards", noun: "hazard",
+		refresh: func(s *AdminServer) { s.world.ClearHazardCache() }}
+	techSpec   = entityCRUD{route: "techs", noun: "tech", searchSubdirs: true, upsert: true, bodyErr: true, okResponse: true}
+	moduleSpec = entityCRUD{route: "modules", noun: "module", searchSubdirs: true, upsert: true, bodyErr: true, okResponse: true}
+)
+
+func (c entityCRUD) find(s *AdminServer, id string) ([]byte, string, error) {
+	if c.searchSubdirs {
+		return findYAMLFileInSubdirs(s.dataDir, c.route, id)
+	}
+	return readYAMLFile(s.dataDir, c.route, id)
+}
+
+// fail writes an entity error in the family's wire style. status is ignored
+// by the body style, whose clients read the error out of a 200.
+func (c entityCRUD) fail(w http.ResponseWriter, status int, msg string) {
+	if c.bodyErr {
+		failJSON(w, msg)
+		return
+	}
+	writeJSONError(w, msg, status)
+}
+
+func (c entityCRUD) invalidate(s *AdminServer) {
+	if c.refresh != nil {
+		c.refresh(s)
+	}
+}
+
+func (c entityCRUD) invalidID() string {
+	if c.bodyErr {
+		return "invalid id"
+	}
+	return "invalid " + c.noun + " id"
+}
+
+func (c entityCRUD) missingID() string {
+	if c.bodyErr {
+		return "missing id"
+	}
+	return "missing " + c.noun + " id"
+}
+
+func (c entityCRUD) notFound(id string) string {
+	if c.bodyErr {
+		return "not found: " + id
+	}
+	return c.noun + " not found"
+}
+
+func (c entityCRUD) jsonErr(err error) string {
+	if c.bodyErr {
+		return "invalid JSON: " + err.Error()
+	}
+	return "invalid json body"
+}
+
+func (c entityCRUD) parseErr(err error) string {
+	if c.bodyErr {
+		return "parse error: " + err.Error()
+	}
+	return "failed to parse " + c.noun + " yaml"
+}
+
+func (c entityCRUD) writeErr(err error) string {
+	if c.bodyErr {
+		return "write error: " + err.Error()
+	}
+	return "failed to write " + c.noun
+}
+
+func (c entityCRUD) readErr(err error) string {
+	if c.bodyErr {
+		return "read existing file: " + err.Error()
+	}
+	return "failed to read existing " + c.noun
+}
+
+func (c entityCRUD) removeErr(err error) string {
+	if c.bodyErr {
+		return "delete error: " + err.Error()
+	}
+	return "failed to delete " + c.noun
+}
+
+func (c entityCRUD) listErr(err error) string {
+	if c.bodyErr {
+		return err.Error()
+	}
+	return "failed to list " + c.route
+}
+
+// desc names an undo entry. The body style uses past-tense verbs ("Created
+// tech x"); the status style uses imperative ones ("Create item x").
+func (c entityCRUD) desc(verb, okVerb, id string) string {
+	if c.okResponse {
+		return okVerb + " " + c.noun + " " + id
+	}
+	return verb + " " + c.noun + " " + id
+}
+
+// handleEntityList serves GET (tree) and POST (create) for one family.
+func (s *AdminServer) handleEntityList(c entityCRUD) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		switch r.Method {
+		case http.MethodGet:
+			tree, err := listYAMLTree(s.dataDir, c.route)
+			if err != nil {
+				c.fail(w, http.StatusInternalServerError, c.listErr(err))
+				return
+			}
+			if tree == nil {
+				tree = &YAMLTree{Root: []string{}, Dirs: map[string][]string{}}
+			}
+			writeJSON(w, tree)
+		case http.MethodPost:
+			s.entityCreate(w, r, c)
+		default:
+			methodNotAllowed(w)
+		}
+	}
+}
+
+// handleEntityByID serves GET/PUT/POST(upsert)/DELETE for one family.
+func (s *AdminServer) handleEntityByID(c entityCRUD) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		id := strings.TrimPrefix(r.URL.Path, "/api/"+c.route+"/")
+		if id == "" {
+			c.fail(w, http.StatusBadRequest, c.missingID())
+			return
+		}
+		if !validEntityID(id) {
+			c.fail(w, http.StatusBadRequest, c.invalidID())
+			return
+		}
+		switch r.Method {
+		case http.MethodGet:
+			s.entityGet(w, id, c)
+		case http.MethodPut:
+			s.entityUpdate(w, r, id, c)
+		case http.MethodPost:
+			if !c.upsert {
+				methodNotAllowed(w)
+				return
+			}
+			s.entityUpdate(w, r, id, c)
+		case http.MethodDelete:
+			s.entityDelete(w, id, c)
+		default:
+			methodNotAllowed(w)
+		}
+	}
+}
+
+func (s *AdminServer) entityGet(w http.ResponseWriter, id string, c entityCRUD) {
+	data, path, err := c.find(s, id)
+	if err != nil {
+		c.fail(w, http.StatusNotFound, c.notFound(id))
+		return
+	}
+	m, err := yamlToMap(data)
+	if err != nil {
+		c.fail(w, http.StatusInternalServerError, c.parseErr(err))
+		return
+	}
+	if c.okResponse {
+		// The body style strips the id before writing, so echo it from the
+		// filename; the status style already writes it into the file.
+		m["id"] = id
+	}
+	m["_path"] = path
+	m["_raw"] = string(data)
+	writeJSON(w, m)
+}
+
+func (s *AdminServer) entityCreate(w http.ResponseWriter, r *http.Request, c entityCRUD) {
+	var m map[string]any
+	if err := readJSON(r, &m); err != nil {
+		c.fail(w, http.StatusBadRequest, c.jsonErr(err))
+		return
+	}
+	id, ok := m["id"].(string)
+	if !ok || strings.TrimSpace(id) == "" {
+		c.fail(w, http.StatusBadRequest, c.missingID())
+		return
+	}
+	if !validEntityID(id) {
+		c.fail(w, http.StatusBadRequest, c.invalidID())
+		return
+	}
+	if _, _, err := c.find(s, id); err == nil {
+		c.fail(w, http.StatusConflict, c.noun+" already exists")
+		return
+	}
+	if c.okResponse {
+		delete(m, "id")
+	}
+	path := filepath.Join(s.dataDir, c.route, id+".yaml")
+	newContent, err := writeMapAsYAML(path, m)
+	if err != nil {
+		c.fail(w, http.StatusInternalServerError, c.writeErr(err))
+		return
+	}
+	s.undoStack.Push(ChangeDesc{
+		Description: c.desc("Create", "Created", id),
+		FilePath:    path,
+		NewContent:  newContent,
+		IsCreate:    true,
+	})
+	c.invalidate(s)
+	if c.okResponse {
+		writeJSON(w, map[string]any{"ok": true, "id": id})
+		return
+	}
+	writeJSON(w, m)
+}
+
+func (s *AdminServer) entityUpdate(w http.ResponseWriter, r *http.Request, id string, c entityCRUD) {
+	var m map[string]any
+	if err := readJSON(r, &m); err != nil {
+		c.fail(w, http.StatusBadRequest, c.jsonErr(err))
+		return
+	}
+	_, path, findErr := c.find(s, id)
+	isCreate := findErr != nil
+	if isCreate && !c.upsert {
+		c.fail(w, http.StatusNotFound, c.notFound(id))
+		return
+	}
+	if isCreate {
+		path = filepath.Join(s.dataDir, c.route, id+".yaml")
+	}
+	var oldContent []byte
+	if !isCreate {
+		var err error
+		oldContent, err = snapshotFile(path)
+		if err != nil {
+			c.fail(w, http.StatusInternalServerError, c.readErr(err))
+			return
+		}
+	}
+	// _path/_raw are editor-only metadata and never belong in the file; the
+	// status style also stores the id, while the body style derives it from
+	// the filename.
+	delete(m, "_path")
+	delete(m, "_raw")
+	if c.okResponse {
+		delete(m, "id")
+	} else {
+		m["id"] = id
+	}
+	newContent, err := writeMapAsYAML(path, m)
+	if err != nil {
+		c.fail(w, http.StatusInternalServerError, c.writeErr(err))
+		return
+	}
+	s.undoStack.Push(ChangeDesc{
+		Description: c.desc("Update", "Updated", id),
+		FilePath:    path,
+		OldContent:  oldContent,
+		NewContent:  newContent,
+		IsCreate:    isCreate,
+	})
+	c.invalidate(s)
+	if c.okResponse {
+		writeJSON(w, map[string]any{"ok": true, "id": id})
+		return
+	}
+	m["_raw"] = string(newContent)
+	writeJSON(w, m)
+}
+
+func (s *AdminServer) entityDelete(w http.ResponseWriter, id string, c entityCRUD) {
+	_, path, err := c.find(s, id)
+	if err != nil {
+		c.fail(w, http.StatusNotFound, c.notFound(id))
+		return
+	}
+	oldContent := backupFile(path)
+	if err := os.Remove(path); err != nil {
+		c.fail(w, http.StatusInternalServerError, c.removeErr(err))
+		return
+	}
+	s.undoStack.Push(ChangeDesc{
+		Description: c.desc("Delete", "Deleted", id),
+		FilePath:    path,
+		OldContent:  oldContent,
+		IsDelete:    true,
+	})
+	c.invalidate(s)
+	if c.okResponse {
+		writeJSON(w, map[string]any{"ok": true, "id": id})
+		return
+	}
+	writeJSON(w, map[string]any{"deleted": id})
+}
+
+// methodNotAllowed writes the shared 405 body. The admin JS throws on any
+// non-200, so the JSON form is safe for both wire styles.
+func methodNotAllowed(w http.ResponseWriter) {
+	http.Error(w, `{"error":"method not allowed"}`, http.StatusMethodNotAllowed)
+}