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;
};