50 lines
1.6 KiB
TypeScript
50 lines
1.6 KiB
TypeScript
import { clamp } from './mood'
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import type { Affinity } from './types'
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const DAY = 86_400_000
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export const GAIN = 0.01
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export const DAILY_CAP = 0.05
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export const LOSS = 0.03
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const IDLE_GRACE_DAYS = 7
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const IDLE_HALF_LIFE_DAYS = 30
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// 升階門檻；降階門檻 = 升階門檻 − 0.05，形成遲滯
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export const UP = [0.3, 0.55, 0.8]
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export const HYSTERESIS = 0.05
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export const dayKey = (ms: number) => new Date(ms).toISOString().slice(0, 10)
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export const initialAffinity = (now: number): Affinity => ({ value: 0, stage: 0, dayKey: dayKey(now), dayGain: 0, lastSeen: now })
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export function stageFor(value: number, current: number): number {
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let s = current
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while (s < UP.length && value >= UP[s]!) s++
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while (s > 0 && value < UP[s - 1]! - HYSTERESIS) s--
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return s
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}
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// 離開超過 7 天後，以 30 天半衰期回到 0
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export function idleDecay(a: Affinity, now: number): Affinity {
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const idleDays = (now - a.lastSeen) / DAY
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if (idleDays <= IDLE_GRACE_DAYS) return a
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const value = a.value * Math.pow(0.5, (idleDays - IDLE_GRACE_DAYS) / IDLE_HALF_LIFE_DAYS)
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return { ...a, value, stage: stageFor(value, a.stage) }
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}
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export function interact(prev: Affinity, kind: 'meaningful' | 'negative', now: number): Affinity {
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let a = idleDecay(prev, now)
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const key = dayKey(now)
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if (a.dayKey !== key) a = { ...a, dayKey: key, dayGain: 0 }
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let { value, dayGain } = a
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if (kind === 'meaningful') {
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const gain = Math.max(0, Math.min(GAIN, DAILY_CAP - dayGain))
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value += gain
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dayGain += gain
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} else {
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value -= LOSS
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}
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value = clamp(value)
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return { value, dayGain, dayKey: key, lastSeen: now, stage: stageFor(value, a.stage) }
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}
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