Lemonade Stand: browser recreation of the Atari 8-bit BASIC game

Faithful day loop - weather report, cost of lemonade rising over the
summer, glasses/signs/price decisions, thunderstorms, heat waves and
street crews - with the $$ LEMONSVILLE DAILY FINANCIAL REPORT $$ laid
out the way it printed.

The simulation is kept out of React so a season can be run headlessly:
a careful player compounds $2.00 into roughly $22 over twelve days,
while an all-in player goes broke about seven times in ten.

Weather scenes are pixel rectangles in SVG and the music is a small
chiptune engine on the Web Audio API, so there are no binary assets.
The screen is locked to a 4:3 tube and never scrolls.

src/game/reducer.ts

@@ -0,0 +1,139 @@
+import { STARTING_ASSETS } from './constants'
+import { isBankrupt } from './engine'
+import type { DayConditions, DayResult, Decision, Phase, Player } from './types'
+
+export interface GameState {
+  phase: Phase
+  seed: number
+  day: number
+  players: Player[]
+  /** Index into players; only the ones still solvent take a turn. */
+  turn: number
+  conditions: DayConditions | null
+  decisions: Record<number, Decision>
+  results: DayResult[]
+  history: DayResult[]
+  /** True while road works were in progress yesterday, so they can run on. */
+  streetCrewYesterday: boolean
+  retired: boolean
+}
+
+export const initialState = (seed: number): GameState => ({
+  phase: 'title',
+  seed,
+  day: 0,
+  players: [],
+  turn: 0,
+  conditions: null,
+  decisions: {},
+  results: [],
+  history: [],
+  streetCrewYesterday: false,
+  retired: false,
+})
+
+export type Action =
+  | { type: 'SHOW_INTRO' }
+  | { type: 'SHOW_SETUP' }
+  | { type: 'START'; names: string[] }
+  | { type: 'BEGIN_DAY'; conditions: DayConditions }
+  | { type: 'OPEN_STAND' }
+  | { type: 'SUBMIT'; playerId: number; decision: Decision }
+  | { type: 'RESOLVE'; results: DayResult[] }
+  | { type: 'NEXT_DAY' }
+  | { type: 'RETIRE' }
+  | { type: 'RESTART'; seed: number }
+
+/** Players who can still afford to open the stand, in seating order. */
+export const activePlayers = (s: GameState) => s.players.filter((p) => !p.bankrupt)
+
+export function reducer(state: GameState, action: Action): GameState {
+  switch (action.type) {
+    case 'SHOW_INTRO':
+      return { ...state, phase: 'intro' }
+
+    case 'SHOW_SETUP':
+      return { ...state, phase: 'setup' }
+
+    case 'START':
+      return {
+        ...state,
+        phase: 'briefing',
+        day: 1,
+        players: action.names.map((name, i) => ({
+          id: i,
+          name: name.trim().toUpperCase() || `PLAYER ${i + 1}`,
+          assets: STARTING_ASSETS,
+          bankrupt: false,
+          bankruptDay: null,
+        })),
+        turn: 0,
+        decisions: {},
+        results: [],
+        history: [],
+      }
+
+    case 'BEGIN_DAY':
+      return {
+        ...state,
+        phase: 'briefing',
+        conditions: action.conditions,
+        decisions: {},
+        results: [],
+        turn: 0,
+      }
+
+    case 'OPEN_STAND':
+      return { ...state, phase: 'decide', turn: 0 }
+
+    case 'SUBMIT': {
+      const decisions = { ...state.decisions, [action.playerId]: action.decision }
+      const active = activePlayers(state)
+      const done = active.every((p) => decisions[p.id] !== undefined)
+      return {
+        ...state,
+        decisions,
+        turn: done ? state.turn : state.turn + 1,
+        phase: done ? 'resolve' : 'decide',
+      }
+    }
+
+    case 'RESOLVE': {
+      const byId = new Map(action.results.map((r) => [r.playerId, r]))
+      const nextDay = state.day + 1
+      return {
+        ...state,
+        phase: 'report',
+        results: action.results,
+        history: [...state.history, ...action.results],
+        streetCrewYesterday: state.conditions?.streetCrew ?? false,
+        players: state.players.map((p) => {
+          const r = byId.get(p.id)
+          if (!r) return p
+          const assets = r.assetsAfter
+          const broke = isBankrupt(assets, nextDay)
+          return {
+            ...p,
+            assets,
+            bankrupt: p.bankrupt || broke,
+            bankruptDay: p.bankrupt ? p.bankruptDay : broke ? state.day : null,
+          }
+        }),
+      }
+    }
+
+    case 'NEXT_DAY': {
+      if (activePlayers(state).length === 0) return { ...state, phase: 'gameover' }
+      return { ...state, phase: 'briefing', day: state.day + 1, turn: 0 }
+    }
+
+    case 'RETIRE':
+      return { ...state, phase: 'gameover', retired: true }
+
+    case 'RESTART':
+      return initialState(action.seed)
+
+    default:
+      return state
+  }
+}