import * as electron from "electron";
import * as fs from "fs-extra";
import * as path from "path";

/* We read/write to this file every time again because this file could be used by multible processes */
const data_file: string = path.join(electron.app.getPath('userData'), "window-bounds.json");

import BrowserWindow = Electron.BrowserWindow;
import Rectangle = Electron.Rectangle;

let _changed_data: {[key: string]:Rectangle} = {};
let _changed_saver: NodeJS.Timer;

export async function save_changes() {
    clearTimeout(_changed_saver);

    try {
        const data = (await fs.pathExists(data_file) ? await fs.readJson(data_file) : {}) || {};
        Object.assign(data, _changed_data);

        await fs.ensureFile(data_file);
        await fs.writeJson(data_file, data);
        path_exists = true;

        _changed_data = {};
    } catch(error) {
        console.warn("Failed to save window bounds: %o", error);
    }
    console.log("Window bounds have been successfully saved!");
}

let path_exists = undefined;
export async function get_last_bounds(key: string) : Promise<Rectangle> {
    try {
        if(typeof(path_exists) === "undefined" ? !(path_exists = await fs.pathExists(data_file)) : !path_exists)
            throw "skip!";

        const data = await fs.readJson(data_file) || {};
        if(data[key])
            return data[key];
    } catch(error) {
        if(error !== "skip!")
            console.warn("Failed to load window bounds for %s: %o", key, error);
    }

    return {
        height: undefined,
        width: undefined,
        x: undefined,
        y: undefined
    }
}

export function track_bounds(key: string, window: BrowserWindow) {
    const events = ['move', 'moved', 'resize'];

    const update_bounds = () => {
        _changed_data[key] = window.getBounds();

        clearTimeout(_changed_saver);
        _changed_saver = setTimeout(save_changes, 1000);
    };

    for(const event of events)
        window.on(event as any, update_bounds);

    window.on('closed', () => {
        for(const event of events)
            window.removeListener(event as any, update_bounds);
    })
}

export async function apply_bounds(key: string, window: BrowserWindow, bounds?: Rectangle, options?: { apply_size?: boolean; apply_position?: boolean }) {
    const screen = electron.screen;

    if(!bounds)
        bounds = await get_last_bounds(key);

    if(!options)
        options = {};

    const original_bounds = window.getBounds();

    if(typeof(options.apply_size) !== "boolean" || options.apply_size) {
        let height = bounds.height > 0 ? bounds.height : original_bounds.height;
        let width = bounds.width > 0 ? bounds.width : original_bounds.width;

        if(height != original_bounds.height || width != original_bounds.width)
            window.setSize(width, height, true);
    }
    if(typeof(options.apply_position) !== "boolean" || options.apply_position) {
        let x = typeof(bounds.x) === "number" ? bounds.x : original_bounds.x;
        let y = typeof(bounds.y) === "number" ? bounds.y : original_bounds.y;

        if(x != original_bounds.x || y != original_bounds.y) {
            const display = screen.getDisplayNearestPoint({ x: x, y: y });
            if(display) {
                const bounds = display.workArea || display.bounds;
                let flag_invalid = false;
                flag_invalid = flag_invalid || bounds.x > x || (bounds.x + bounds.width) < x;
                flag_invalid = flag_invalid || bounds.y > x || (bounds.y + bounds.height) < y;
                if(!flag_invalid) {
                    window.setPosition(x, y, true);
                    console.log("Updating position for %s", key);
                }
            }
        }
    }
}