invention purchase, at least, how I think they should work

packages/domain/src/validation.ts

@@ -37,6 +37,25 @@ export const MAX_CLUB_DESCRIPTION_LENGTH = 512
 export const MAX_EVENT_NAME_LENGTH = 64
 export const MAX_EVENT_DESCRIPTION_LENGTH = 512
 
+/**
+ * Invention limits. A name is a title a player types into the invention-save box and
+ * reads back in a browse tile, so it allows the punctuation a title needs — but
+ * nothing else, since it is also what invention search matches on. The minimum is real:
+ * one- and two-character names are unsearchable and unreadable in a tile, and the client
+ * offers `Untitled` rather than an empty box.
+ */
+export const MIN_INVENTION_NAME_LENGTH = 3
+export const MAX_INVENTION_NAME_LENGTH = 24
+export const MAX_INVENTION_DESCRIPTION_LENGTH = 512
+
+/**
+ * One invention tag. Short and letters-only because tags are a controlled vocabulary the
+ * browse chips are derived from (see `getInventionTagFilters`) — a tag with digits,
+ * punctuation or spaces makes a chip nobody else will ever type again. Tags are stored
+ * lowercased, so the rule is checked against the normalized form, not what was typed.
+ */
+export const MAX_INVENTION_TAG_LENGTH = 15
+
 /**
  * Length in code points rather than UTF-16 units, so an emoji or other astral character
  * counts once instead of twice — the way a player counts what they typed.
@@ -74,6 +93,69 @@ export function nameRejection(value: string, label: string, max: number): string
 	return null
 }
 
+/**
+ * Letters, digits, spaces, dashes and colons — the title charset. Wider than
+ * `NAME_PATTERN` because an invention is a thing with a name ("Grappling Hook v2",
+ * "Speed-Boost Pad"), not an identifier someone types into a sign-in box. Still no
+ * arbitrary Unicode, for the same homoglyph reasons.
+ *
+ * The colon is not decorative: an invention the player never named is called after the
+ * moment it was saved (`071126 13:10:50`), generated by the CLIENT, so a rule without it
+ * would refuse every unnamed save the game makes. The dash stays last in the class so it
+ * reads as a literal rather than a range.
+ */
+const INVENTION_NAME_PATTERN = /^[A-Za-z0-9 :-]+$/
+
+/** Lowercase letters only — the normalized form a tag is stored in. */
+const INVENTION_TAG_PATTERN = /^[a-z]+$/
+
+/**
+ * Why a player-supplied invention name is unacceptable, or `null` when it's fine.
+ *
+ * Callers pass the TRIMMED name: leading and trailing spaces are the player's typing,
+ * not part of what they named the thing, and counting them toward the minimum would let
+ * `"  a  "` through.
+ */
+export function inventionNameRejection(value: string): string | null {
+	if (glyphLength(value) < MIN_INVENTION_NAME_LENGTH) {
+		return `Invention names must be at least ${MIN_INVENTION_NAME_LENGTH} characters.`
+	}
+	if (glyphLength(value) > MAX_INVENTION_NAME_LENGTH) {
+		return `Invention names can be at most ${MAX_INVENTION_NAME_LENGTH} characters.`
+	}
+	if (!INVENTION_NAME_PATTERN.test(value)) {
+		return 'Invention names can only contain letters, numbers, spaces, dashes and colons.'
+	}
+	return null
+}
+
+/**
+ * Why an invention description is unacceptable, or `null` when it's fine. Length only —
+ * a description is prose, so nothing is refused for the characters it's made of, and an
+ * empty one is fine (it's how a creator clears the field).
+ */
+export function inventionDescriptionRejection(value: string): string | null {
+	if (glyphLength(value) > MAX_INVENTION_DESCRIPTION_LENGTH) {
+		return `Invention descriptions can be at most ${MAX_INVENTION_DESCRIPTION_LENGTH} characters.`
+	}
+	return null
+}
+
+/**
+ * Why an invention tag is unacceptable, or `null` when it's fine. Pass the NORMALIZED
+ * tag (trimmed and lowercased, as `setInventionTags` stores it) — checking what was typed
+ * instead would refuse `Racing` for a capital that never reaches the database.
+ */
+export function inventionTagRejection(value: string): string | null {
+	if (value.length > MAX_INVENTION_TAG_LENGTH) {
+		return `Invention tags can be at most ${MAX_INVENTION_TAG_LENGTH} characters.`
+	}
+	if (!INVENTION_TAG_PATTERN.test(value)) {
+		return 'Invention tags can only contain letters.'
+	}
+	return null
+}
+
 /**
  * Whether a supplied email is one worth storing — RFC 5321/5322 syntax, via `isemail`.
  *