import type { SupportedLocale } from "./types.ts";

export interface LocaleStrings {
	readonly locale: SupportedLocale;
	readonly on: string;
	readonly running: string;
	readonly off: string;
	readonly overdue: string;
	readonly next: string;
	readonly planned: string;
	readonly late: string;
	readonly once: string;
	tasks(count: number): string;
	runningCount(count: number): string;
	overdueCount(count: number): string;
	pausedCount(count: number): string;
	every(value: string): string;
}

const ZH_CN: LocaleStrings = {
	locale: "zh-CN",
	on: "已启用",
	running: "执行中",
	off: "已暂停",
	overdue: "已到期",
	next: "下次",
	planned: "计划",
	late: "延迟",
	once: "一次性",
	tasks: (count) => `${count} 个任务`,
	runningCount: (count) => `${count} 个执行中`,
	overdueCount: (count) => `${count} 个已到期`,
	pausedCount: (count) => `${count} 个已暂停`,
	every: (value) => `每${value}`,
};

const EN_US: LocaleStrings = {
	locale: "en-US",
	on: "ON",
	running: "running",
	off: "OFF",
	overdue: "overdue",
	next: "next",
	planned: "planned",
	late: "late",
	once: "once",
	tasks: (count) => `${count} task${count === 1 ? "" : "s"}`,
	runningCount: (count) => `${count} running`,
	overdueCount: (count) => `${count} overdue`,
	pausedCount: (count) => `${count} paused`,
	every: (value) => `every ${value}`,
};

/**
 * 根据请求值和系统 locale 解析插件语言.
 *
 * @param requested 显式语言配置, 支持 auto、zh-CN 和 en-US
 * @param detectedLocale 系统检测到的 locale, 主要用于测试
 * @returns 实际使用的语言
 */
export function resolveLocale(requested?: string, detectedLocale?: string): SupportedLocale {
	const value = requested?.trim().toLowerCase();
	if (value === "zh" || value === "zh-cn" || value === "zh_hans") return "zh-CN";
	if (value === "en" || value === "en-us" || value === "en_gb" || value === "en-gb") return "en-US";
	const detected = (detectedLocale ?? Intl.DateTimeFormat().resolvedOptions().locale).toLowerCase();
	return detected.startsWith("zh") ? "zh-CN" : "en-US";
}

/**
 * 返回指定语言的固定文案.
 *
 * @param locale 实际使用的语言
 * @returns 固定文案集合
 */
export function getLocaleStrings(locale: SupportedLocale): LocaleStrings {
	return locale === "zh-CN" ? ZH_CN : EN_US;
}