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e069894c4e
- 主题（浅色/深色/跟随系统）与正文字号（标准/大/特大）按账号存在本机， 账号切换不串、退出回默认；深色走 html[data-theme] 与 Element Plus 的 html.dark - style.css 收敛为语义调色板：:root 的 53 个变量是文件内仅有的颜色字面量， 其余规则全部走 var()，暗色只覆盖变量 - 字号经 --reader-font-scale 只作用于阅读面，不做全局缩放 - 阅读位置按账号＋章节保存滚动比例与该章 content_sha256，正文换版本后不恢复 - 复习页键盘：空格/Enter 显示答案、1/2/3 评分；输入控件与聚焦按钮的按键不被劫持 - 站点头部新增「显示」控件，七个学习页面共用 - Playwright 新增 390×844 hasTouch 的 mobile 项目与移动用例（无溢出、可返回、 触摸滑动不误开面板、深色与字号持久化、账号隔离）；新增主题变量回归用例 - Wiki 记录 Architecture、Business-Rules、Local-Development 与需求更新
80 lines
3.1 KiB
TypeScript
80 lines
3.1 KiB
TypeScript
/**
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* Remembers where the reader stopped in a chapter. The position belongs to one account and one
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* chapter, and it is tied to the chapter's content version: after the text is replaced, the old
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* offset would point at different words, so it is dropped instead of restored.
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*
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* The value is a scroll ratio rather than a pixel offset, because the same chapter is read at
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* different window widths (desktop and phone) where a pixel offset would land in the wrong place.
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* This is local to the browser: it is not synced across devices.
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*/
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export const POSITION_KEY_PREFIX = 'lexgo-learner-position:'
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export interface ReadingPosition {
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ratio: number
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sha: string
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at: string
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}
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export function positionKey(userId: number | null, chapterId: number): string | null {
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if (userId === null || !Number.isInteger(chapterId) || chapterId <= 0) return null
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return `${POSITION_KEY_PREFIX}${userId}:${chapterId}`
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}
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/** Clamps a stored ratio into [0,1]; anything else is treated as "no usable position". */
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export function normalizeRatio(value: unknown): number | null {
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if (typeof value !== 'number' || !Number.isFinite(value)) return null
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if (value <= 0) return null
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return Math.min(value, 1)
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}
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export function readPosition(storage: Storage, userId: number | null, chapterId: number, sha: string): ReadingPosition | null {
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const key = positionKey(userId, chapterId)
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if (key === null) return null
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try {
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const raw = storage.getItem(key)
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if (raw === null) return null
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const parsed = JSON.parse(raw) as Partial<ReadingPosition> | null
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const ratio = normalizeRatio(parsed?.ratio)
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// A different content version means the offset describes words that are no longer there.
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if (ratio === null || !parsed || parsed.sha !== sha) return null
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return { ratio, sha, at: typeof parsed.at === 'string' ? parsed.at : '' }
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} catch {
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return null
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}
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}
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export function writePosition(storage: Storage, userId: number | null, chapterId: number, sha: string, ratio: number, now = new Date()): void {
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const key = positionKey(userId, chapterId)
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const usable = normalizeRatio(ratio)
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if (key === null || usable === null || !sha) return
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try {
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storage.setItem(key, JSON.stringify({ ratio: usable, sha, at: now.toISOString() } satisfies ReadingPosition))
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} catch {
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// A full or disabled store must not break reading.
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}
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}
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export function clearPosition(storage: Storage, userId: number | null, chapterId: number): void {
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const key = positionKey(userId, chapterId)
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if (key === null) return
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try {
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storage.removeItem(key)
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} catch {
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// Ignored for the same reason as above.
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}
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}
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export interface ReadingPositionOptions {
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/** The scrollable document the reader lives in. */
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view: () => Window
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/** The current scrollable height, used to turn a pixel offset into a ratio. */
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scrollHeight: () => number
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}
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/** Turns the current window scroll offset into the ratio that is stored. */
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export function currentRatio(view: Pick<Window, 'scrollY' | 'innerHeight'>, scrollHeight: number): number {
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const scrollable = scrollHeight - view.innerHeight
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if (scrollable <= 0) return 0
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return Math.min(Math.max(view.scrollY / scrollable, 0), 1)
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}
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