import { v4 as uuid } from "uuid";

import { themeProps, Theme } from "./theme";

export type Default = null;
export type Color = string;
export type FuncName = "alpha" | "darken" | "lighten";
export type Func = { type: "func"; name: FuncName; arg: number; value: string };
export type RefProp = { type: "refProp"; key: string };
export type RefConst = { type: "refConst"; key: string };
export type Css = { type: "css"; value: string };

export type ThemeValue = Color | Func | RefProp | RefConst | Css | Default;

export type ThemeViewModel = [string, ThemeValue][];

export const fromThemeString = (str?: string): ThemeValue => {
	if (!str) return null;
	if (str.startsWith(":")) {
		const parts = str.slice(1).split("<");
		const name = parts[0] as FuncName;
		const arg = parseFloat(parts[1]);
		const value = parts[2].startsWith("@") ? parts[2].slice(1) : "";
		return { type: "func", name, arg, value };
	} else if (str.startsWith("@")) {
		return {
			type: "refProp",
			key: str.slice(1),
		};
	} else if (str.startsWith("$")) {
		return {
			type: "refConst",
			key: str.slice(1),
		};
	} else if (str.startsWith('"')) {
		return {
			type: "css",
			value: str.substr(1).trim(),
		};
	} else {
		return str;
	}
};

export const toThemeString = (
	value: Color | Func | RefProp | RefConst | Css,
) => {
	if (typeof value === "string") return value;
	switch (value.type) {
		case "func":
			return `:${value.name}<${value.arg}<@${value.value}`;
		case "refProp":
			return `@${value.key}`;
		case "refConst":
			return `$${value.key}`;
		case "css":
			return `" ${value.value}`;
	}
};

export const convertToMisskeyTheme = (
	vm: ThemeViewModel,
	name: string,
	desc: string,
	author: string,
	base: "dark" | "light",
): Theme => {
	const props = {} as { [key: string]: string };
	for (const [key, value] of vm) {
		if (value === null) continue;
		props[key] = toThemeString(value);
	}

	return {
		id: uuid(),
		name,
		desc,
		author,
		props,
		base,
	};
};

export const convertToViewModel = (theme: Theme): ThemeViewModel => {
	const vm: ThemeViewModel = [];
	// プロパティの登録
	vm.push(
		...themeProps.map(
			(key) => [key, fromThemeString(theme.props[key])] as [string, ThemeValue],
		),
	);

	// 定数の登録
	const consts = Object.keys(theme.props)
		.filter((k) => k.startsWith("$"))
		.map((k) => [k, fromThemeString(theme.props[k])] as [string, ThemeValue]);

	vm.push(...consts);
	return vm;
};