/*
	Spacebar: A FOSS re-implementation and extension of the Discord.com backend.
	Copyright (C) 2023 Spacebar and Spacebar Contributors

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Affero General Public License as published
	by the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU Affero General Public License for more details.

	You should have received a copy of the GNU Affero General Public License
	along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

/* eslint-disable @typescript-eslint/no-explicit-any */

import { route } from "@spacebar/api";
import { DiscordApiErrors, Guild } from "@spacebar/util";
import { Request, Response, Router } from "express";
import fs from "node:fs";
import { HTTPError } from "lambert-server";
import path from "node:path";
import { storage } from "@spacebar/cdn";

const router: Router = Router({ mergeParams: true });

// TODO: use svg templates instead of node-canvas for improved performance and to change it easily

// https://discord.com/developers/docs/resources/guild#get-guild-widget-image
// TODO: Cache the response
router.get(
    "/",
    route({
        responses: {
            200: {},
            400: {
                body: "APIErrorResponse",
            },
            404: {
                body: "APIErrorResponse",
            },
        },
    }),
    async (req: Request, res: Response) => {
        const { guild_id } = req.params as { [key: string]: string };

        const guild = await Guild.findOneOrFail({ where: { id: guild_id } });
        if (!guild.widget_enabled) throw DiscordApiErrors.EMBED_DISABLED;

        // Fetch guild information
        const icon = "avatars/" + guild_id + "/" + guild.icon;
        const name = guild.name;
        const presence = guild.presence_count + " ONLINE";

        // Fetch parameter
        const style = req.query.style?.toString() || "shield";
        if (!["shield", "banner1", "banner2", "banner3", "banner4"].includes(style)) {
            throw new HTTPError("Value must be one of ('shield', 'banner1', 'banner2', 'banner3', 'banner4').", 400);
        }

        // Setup canvas
        const { createCanvas, loadImage } = require("canvas");
        const sizeOf = require("image-size");

        // TODO: Widget style templates need Spacebar branding
        const source = path.join(__dirname, "..", "..", "..", "..", "..", "assets", "widget", `${style}.png`);
        if (!fs.existsSync(source)) {
            throw new HTTPError("Widget template does not exist.", 400);
        }

        // Create base template image for parameter
        const { width, height } = await sizeOf(source);
        const canvas = createCanvas(width, height);
        const ctx = canvas.getContext("2d");
        const template = await loadImage(source);
        ctx.drawImage(template, 0, 0);

        // Add the guild specific information to the template asset image
        switch (style) {
            case "shield":
                ctx.textAlign = "center";
                drawText(ctx, 73, 13, "#FFFFFF", "thin 10px Verdana", presence);
                break;
            case "banner1":
                if (icon) await drawIcon(ctx, 20, 27, 50, icon);
                drawText(ctx, 83, 51, "#FFFFFF", "12px Verdana", name, 22);
                drawText(ctx, 83, 66, "#C9D2F0FF", "thin 11px Verdana", presence);
                break;
            case "banner2":
                if (icon) await drawIcon(ctx, 13, 19, 36, icon);
                drawText(ctx, 62, 34, "#FFFFFF", "12px Verdana", name, 15);
                drawText(ctx, 62, 49, "#C9D2F0FF", "thin 11px Verdana", presence);
                break;
            case "banner3":
                if (icon) await drawIcon(ctx, 20, 20, 50, icon);
                drawText(ctx, 83, 44, "#FFFFFF", "12px Verdana", name, 27);
                drawText(ctx, 83, 58, "#C9D2F0FF", "thin 11px Verdana", presence);
                break;
            case "banner4":
                if (icon) await drawIcon(ctx, 21, 136, 50, icon);
                drawText(ctx, 84, 156, "#FFFFFF", "13px Verdana", name, 27);
                drawText(ctx, 84, 171, "#C9D2F0FF", "thin 12px Verdana", presence);
                break;
            default:
                throw new HTTPError("Value must be one of ('shield', 'banner1', 'banner2', 'banner3', 'banner4').", 400);
        }

        // Return final image
        const buffer = canvas.toBuffer("image/png");
        res.set("Content-Type", "image/png");
        res.set("Cache-Control", "public, max-age=3600");
        return res.send(buffer);
    },
);

async function drawIcon(canvas: any, x: number, y: number, scale: number, icon: string) {
    const { loadImage } = require("canvas");
    const img = await loadImage(await storage.get(icon));

    // Do some canvas clipping magic!
    canvas.save();
    canvas.beginPath();

    const r = scale / 2; // use scale to determine radius
    canvas.arc(x + r, y + r, r, 0, 2 * Math.PI, false); // start circle at x, and y coords + radius to find center

    canvas.clip();
    canvas.drawImage(img, x, y, scale, scale);

    canvas.restore();
}

function drawText(canvas: any, x: number, y: number, color: string, font: string, text: string, maxcharacters?: number) {
    canvas.fillStyle = color;
    canvas.font = font;
    if (text.length > (maxcharacters || 0) && maxcharacters) text = text.slice(0, maxcharacters) + "...";
    canvas.fillText(text, x, y);
}

export default router;