feat: pure scan-flow state machine

2026-08-29 22:25:53 +02:00
parent 70b7fdbe1b
commit 890e7da3a7
2 changed files with 217 additions and 0 deletions
--- a/web/src/scan/reducer.ts
+++ b/web/src/scan/reducer.ts
@@ -0,0 +1,76 @@
+import type { Candidate, Item, ReleasePreview } from '../types.js'
+
+export type ScanErrorKind = 'not_found' | 'no_discogs_token' | 'rate_limited' | 'server'
+
+export type ScanState =
+  | { phase: 'scan' }
+  | { phase: 'looking'; code: string }
+  | { phase: 'candidates'; code: string; candidates: Candidate[] }
+  | {
+      phase: 'confirm'
+      code: string | null
+      candidate: Candidate
+      preview: ReleasePreview | null
+      matchAlbumId: number | null
+      adding: boolean
+      addError: string | null
+    }
+  | { phase: 'added'; item: Item }
+  | { phase: 'error'; kind: ScanErrorKind; code: string | null }
+
+export const INITIAL_SCAN_STATE: ScanState = { phase: 'scan' }
+
+export type ScanAction =
+  | { type: 'DETECT'; code: string }
+  | { type: 'CANDIDATES'; code: string; candidates: Candidate[] }
+  | { type: 'NOT_FOUND'; code: string }
+  | { type: 'ERROR'; kind: ScanErrorKind; code: string | null }
+  | { type: 'SELECT'; candidate: Candidate }
+  | { type: 'PREVIEW'; preview: ReleasePreview }
+  | { type: 'SET_MATCH'; albumId: number }
+  | { type: 'CLEAR_MATCH' }
+  | { type: 'ADD_START' }
+  | { type: 'ADDED'; item: Item }
+  | { type: 'ADD_ERROR'; message: string }
+  | { type: 'RESET' }
+
+export function scanReducer(state: ScanState, action: ScanAction): ScanState {
+  switch (action.type) {
+    case 'DETECT':
+      return state.phase === 'scan' ? { phase: 'looking', code: action.code } : state
+    case 'CANDIDATES':
+      return state.phase === 'looking' ? { phase: 'candidates', code: action.code, candidates: action.candidates } : state
+    case 'NOT_FOUND':
+      return state.phase === 'looking' ? { phase: 'error', kind: 'not_found', code: action.code } : state
+    case 'ERROR':
+      return state.phase === 'looking' || state.phase === 'candidates' || state.phase === 'confirm'
+        ? { phase: 'error', kind: action.kind, code: action.code }
+        : state
+    case 'SELECT':
+      return state.phase === 'candidates'
+        ? {
+            phase: 'confirm',
+            code: state.code,
+            candidate: action.candidate,
+            preview: null,
+            matchAlbumId: null,
+            adding: false,
+            addError: null,
+          }
+        : state
+    case 'PREVIEW':
+      return state.phase === 'confirm' ? { ...state, preview: action.preview } : state
+    case 'SET_MATCH':
+      return state.phase === 'confirm' ? { ...state, matchAlbumId: action.albumId } : state
+    case 'CLEAR_MATCH':
+      return state.phase === 'confirm' ? { ...state, matchAlbumId: null } : state
+    case 'ADD_START':
+      return state.phase === 'confirm' && state.preview ? { ...state, adding: true, addError: null } : state
+    case 'ADDED':
+      return state.phase === 'confirm' ? { phase: 'added', item: action.item } : state
+    case 'ADD_ERROR':
+      return state.phase === 'confirm' ? { ...state, adding: false, addError: action.message } : state
+    case 'RESET':
+      return INITIAL_SCAN_STATE
+  }
+}