feat(model): make useMacroplan own a library of named plans

src/composables/useMacroplan.ts

@@ -1,19 +1,104 @@
-import { ref, computed, watch } from 'vue'
+import { ref, shallowRef, computed, watch } from 'vue'
 import { parseMacroplan } from '../model/parse'
 import { buildPlan } from '../model/plan'
 import type { Plan } from '../model/types'
 import { SAMPLE_PLAN } from '../data/sample'
 
-const STORAGE_KEY = 'macroplan:source'
+const STORAGE_KEY = 'macroplan:library'
+const LEGACY_KEY = 'macroplan:source'
+
+export interface StoredPlan {
+  id: string
+  name: string
+  source: string
+}
+
+interface Library {
+  version: 1
+  activeId: string
+  plans: StoredPlan[]
+}
+
+/** The source's title if it fully parses, else null (so the cached name only
+ *  ever updates on a valid parse). */
+function titleOf(source: string): string | null {
+  try {
+    return parseMacroplan(source).title
+  } catch {
+    return null
+  }
+}
+
+function newStoredPlan(source: string): StoredPlan {
+  return { id: crypto.randomUUID(), name: titleOf(source) ?? 'Untitled', source }
+}
+
+function save(lib: Library): void {
+  try {
+    localStorage.setItem(STORAGE_KEY, JSON.stringify(lib))
+  } catch {
+    /* localStorage may be full or blocked — autosave is best-effort */
+  }
+}
+
+/** Resolve the initial library: existing store → legacy migration → fresh seed.
+ *  Always persisted before returning so a migrated/seeded library survives a
+ *  reload even if the user never edits. */
+function loadLibrary(): Library {
+  let result: Library | null = null
+
+  const raw = localStorage.getItem(STORAGE_KEY)
+  if (raw) {
+    try {
+      const lib = JSON.parse(raw) as Library
+      if (lib && Array.isArray(lib.plans) && lib.plans.length > 0) {
+        if (!lib.plans.some((p) => p.id === lib.activeId)) lib.activeId = lib.plans[0].id
+        result = { version: 1, activeId: lib.activeId, plans: lib.plans }
+      }
+    } catch {
+      /* corrupt JSON → fall through to migration / seed */
+    }
+  }
+
+  if (!result) {
+    const legacy = localStorage.getItem(LEGACY_KEY)
+    if (legacy != null) {
+      const p = newStoredPlan(legacy)
+      localStorage.removeItem(LEGACY_KEY)
+      result = { version: 1, activeId: p.id, plans: [p] }
+    } else {
+      const seed = newStoredPlan(SAMPLE_PLAN)
+      result = { version: 1, activeId: seed.id, plans: [seed] }
+    }
+  }
+
+  save(result)
+  return result
+}
 
 /**
- * Authoring state for a single Macroplan: the TOML source (autosaved to
- * localStorage), the parsed Plan, and the current parse error. The last
- * successfully-parsed Plan keeps rendering through transient typos (F3).
+ * Owns the Library — the collection of named Macroplans in localStorage
+ * (ADR-0002). Exposes the active plan's authoring state (source / parsed plan /
+ * error, with the last good render kept through transient typos, F3) plus the
+ * switch / create / delete operations over the library.
  */
 export function useMacroplan() {
-  const source = ref(localStorage.getItem(STORAGE_KEY) ?? SAMPLE_PLAN)
-  const lastGood = ref<Plan | null>(null)
+  const lib = ref<Library>(loadLibrary())
+  const lastGood = shallowRef<Plan | null>(null)
+
+  const active = computed<StoredPlan>(
+    () => lib.value.plans.find((p) => p.id === lib.value.activeId) ?? lib.value.plans[0],
+  )
+
+  const source = computed<string>({
+    get: () => active.value.source,
+    set: (v) => {
+      const p = active.value
+      p.source = v
+      const t = titleOf(v)
+      if (t) p.name = t // refresh the cached label only on a valid parse
+    },
+  })
 
   const parsed = computed<{ plan: Plan | null; error: string | null }>(() => {
     try {
@@ -31,18 +116,44 @@ export function useMacroplan() {
     { immediate: true },
   )
 
-  watch(source, (v) => {
-    try {
-      localStorage.setItem(STORAGE_KEY, v)
-    } catch {
-      /* localStorage may be full or blocked — autosave is best-effort */
-    }
-  })
+  // Persist the whole library on any change (best-effort, like the old autosave).
+  watch(lib, (l) => save(l), { deep: true })
+
+  // Switching plans drops the prior render so a broken target shows its own
+  // error/empty state, not the previous plan's grid.
+  function switchTo(id: string): void {
+    lib.value.activeId = id
+    lastGood.value = parsed.value.plan
+  }
 
   return {
     source,
     plan: computed(() => parsed.value.plan ?? lastGood.value),
     error: computed(() => parsed.value.error),
+    plans: computed(() => lib.value.plans.map((p) => ({ id: p.id, name: p.name }))),
+    activeId: computed(() => lib.value.activeId),
+    selectPlan: (id: string) => {
+      if (lib.value.plans.some((p) => p.id === id)) switchTo(id)
+    },
+    newPlan: () => {
+      const p = newStoredPlan(SAMPLE_PLAN)
+      lib.value.plans.push(p)
+      switchTo(p.id)
+    },
+    deletePlan: (id: string) => {
+      const idx = lib.value.plans.findIndex((p) => p.id === id)
+      if (idx === -1) return
+      const wasActive = lib.value.activeId === id
+      lib.value.plans.splice(idx, 1)
+      if (lib.value.plans.length === 0) {
+        const seed = newStoredPlan(SAMPLE_PLAN)
+        lib.value.plans.push(seed)
+        switchTo(seed.id)
+      } else if (wasActive) {
+        switchTo(lib.value.plans[Math.max(0, idx - 1)].id)
+      }
+    },
+    // TODO(task 4): remove once App.vue drops the "Reset to sample" button.
     resetToSample: () => {
       source.value = SAMPLE_PLAN
     },