/*
	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/>.
*/

import { existsSync } from "fs";
import fs from "fs/promises";
import { OrmUtils } from "..";
import { ConfigValue } from "../config";
import { ConfigEntity } from "../entities";
import { JsonValue } from "@protobuf-ts/runtime";

// TODO: yaml instead of json
const overridePath = process.env.CONFIG_PATH ?? "";

let config: ConfigValue;
let pairs: ConfigEntity[];

// TODO: use events to inform about config updates
// Config keys are separated with _

export class Config {
    public static async init(force: boolean = false) {
        if (config && !force) return config;
        console.log("[Config] Loading configuration...");
        if (!process.env.CONFIG_PATH) {
            pairs = await validateConfig();
            config = pairsToConfig(pairs);
        } else {
            console.log(`[Config] Using CONFIG_PATH rather than database:`, process.env.CONFIG_PATH);
            if (existsSync(process.env.CONFIG_PATH)) {
                const file = JSON.parse((await fs.readFile(process.env.CONFIG_PATH)).toString());
                config = file;
            } else config = new ConfigValue();
            pairs = generatePairs(config);
        }

        // If a config doesn't exist, create it.
        if (Object.keys(config).length == 0) config = new ConfigValue();

        config = OrmUtils.mergeDeep({}, { ...new ConfigValue() }, config);

        // TODO: factor this out someday
        if (process.env.CDN_SIGNATURE_PATH) config.security.cdnSignatureKey = (await fs.readFile(process.env.CDN_SIGNATURE_PATH, "utf-8")).trim();
        if (process.env.LEGACY_JWT_SECRET_PATH) config.security.jwtSecret = (await fs.readFile(process.env.LEGACY_JWT_SECRET_PATH, "utf-8")).trim();
        if (process.env.MAILJET_API_KEY_PATH) config.email.mailjet.apiKey = (await fs.readFile(process.env.MAILJET_API_KEY_PATH, "utf-8")).trim();
        if (process.env.MAILJET_API_SECRET_PATH) config.email.mailjet.apiSecret = (await fs.readFile(process.env.MAILJET_API_SECRET_PATH, "utf-8")).trim();
        if (process.env.SMTP_PASSWORD_PATH) config.email.smtp.password = (await fs.readFile(process.env.SMTP_PASSWORD_PATH, "utf-8")).trim();
        if (process.env.GIF_API_KEY_PATH) config.gif.apiKey = (await fs.readFile(process.env.GIF_API_KEY_PATH, "utf-8")).trim();
        if (process.env.RABBITMQ_HOST) config.rabbitmq.host = process.env.RABBITMQ_HOST.trim();
        if (process.env.RABBITMQ_HOST_PATH) config.rabbitmq.host = (await fs.readFile(process.env.RABBITMQ_HOST_PATH, "utf-8")).trim();
        if (process.env.ABUSEIPDB_API_KEY_PATH) config.security.abuseIpDbApiKey = (await fs.readFile(process.env.ABUSEIPDB_API_KEY_PATH, "utf-8")).trim();
        if (process.env.CAPTCHA_SECRET_KEY_PATH) config.security.captcha.secret = (await fs.readFile(process.env.CAPTCHA_SECRET_KEY_PATH, "utf-8")).trim();
        if (process.env.CAPTCHA_SITE_KEY_PATH) config.security.captcha.sitekey = (await fs.readFile(process.env.CAPTCHA_SITE_KEY_PATH, "utf-8")).trim();
        if (process.env.IPDATA_API_KEY_PATH) config.security.ipdataApiKey = (await fs.readFile(process.env.IPDATA_API_KEY_PATH, "utf-8")).trim();
        if (process.env.REQUEST_SIGNATURE_PATH) config.security.requestSignature = (await fs.readFile(process.env.REQUEST_SIGNATURE_PATH, "utf-8")).trim();

        await this.set(config);
        validateFinalConfig(config);
        return config;
    }
    public static get() {
        if (!config) {
            // If we haven't initialised the config yet, return default config.
            // Typeorm instantiates each entity once when initialising database,
            // which means when we use config values as default values in entity classes,
            // the config isn't initialised yet and would throw an error about the config being undefined.

            return new ConfigValue();
        }

        return config;
    }
    public static set(val: Partial<ConfigValue>) {
        if (!config || !val) return;
        config = OrmUtils.mergeDeep(config);

        return applyConfig(config);
    }
}

// TODO: better types
const generatePairs = (obj: object | null, key = ""): ConfigEntity[] => {
    if (typeof obj == "object" && obj != null) {
        return Object.keys(obj)
            .map((k) =>
                // eslint-disable-next-line @typescript-eslint/no-explicit-any
                generatePairs((obj as any)[k], key ? `${key}_${k}` : k),
            )
            .flat();
    }

    const ret = new ConfigEntity();
    ret.key = key;
    ret.value = obj;
    return [ret];
};

async function applyConfig(val: ConfigValue) {
    if (process.env.CONFIG_PATH)
        if (!process.env.CONFIG_READONLY) await fs.writeFile(overridePath, JSON.stringify(val, null, 4));
        else console.log("[WARNING] JSON config file in use, and writing is disabled! Programmatic config changes will not be persisted, and your config will not get updated!");
    else {
        const pairs = generatePairs(val);
        // keys are sorted to try to influence database order...
        await Promise.all(pairs.sort((x, y) => (x.key > y.key ? 1 : -1)).map((pair) => pair.save()));
    }
    return val;
}

function pairsToConfig(pairs: ConfigEntity[]) {
    // TODO: typings
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    const value: any = {};

    pairs.forEach((p) => {
        const keys = p.key.split("_");
        let obj = value;
        let prev = "";
        let prevObj = obj;
        let i = 0;

        for (const key of keys) {
            if (!isNaN(Number(key)) && !prevObj[prev]?.length) prevObj[prev] = obj = [];
            if (i++ === keys.length - 1) obj[key] = p.value;
            else if (!obj[key]) obj[key] = {};

            prev = key;
            prevObj = obj;
            obj = obj[key];
        }
    });

    return value as ConfigValue;
}

const validateConfig = async () => {
    let hasErrored = false;
    const totalStartTime = new Date();
    const config = await ConfigEntity.find({ select: { key: true } });

    for (const row in config) {
        // extension methods...
        if (typeof config[row] === "function") continue;

        try {
            const found = await ConfigEntity.findOne({
                where: { key: config[row].key },
            });
            if (!found) continue;
            config[row] = found;
        } catch (e) {
            console.error(`Config key '${config[row].key}' has invalid JSON value : ${(e as Error)?.message}`);
            hasErrored = true;
        }
    }

    console.log("[Config] Total config load time:", new Date().getTime() - totalStartTime.getTime(), "ms");

    if (hasErrored) {
        console.error("[Config] Your config has invalid values. Fix them first https://docs.spacebar.chat/setup/server/configuration");
        process.exit(1);
    }

    return config;
};

function validateFinalConfig(config: ConfigValue) {
    let hasErrors = false;
    function assertConfig(path: string, condition: (val: JsonValue) => boolean, recommendedValue: string) {
        // _ to separate keys
        const keys = path.split("_");
        let obj: never = config as never;

        for (const key of keys) {
            if (obj == null || !(key in obj)) {
                console.warn(`[Config] Missing config value for '${path}'. Recommended value: ${recommendedValue}`);
                return;
            }
            obj = obj[key];
        }

        if (!condition(obj)) {
            console.warn(`[Config] Invalid config value for '${path}': ${obj}. Recommended value: ${recommendedValue}`);
            hasErrors = true;
        }
    }

    assertConfig(
        "general_serverName",
        (v) => v != null,
        'A valid domain hosting your .well-known (defaulting to https at port 443), eg. "spacebar.chat" or "http://localhost:3001"',
    );
    assertConfig("api_endpointPublic", (v) => v != null, 'A valid public API endpoint URL, eg. "http://localhost:3001/api/v9"');
    assertConfig("cdn_endpointPublic", (v) => v != null, 'A valid public CDN endpoint URL, eg. "http://localhost:3003/"');
    assertConfig("cdn_endpointPrivate", (v) => v != null, 'A valid private CDN endpoint URL, eg. "http://localhost:3003/" - must be routable from the API server!');
    assertConfig("gateway_endpointPublic", (v) => v != null, 'A valid public gateway endpoint URL, eg. "ws://localhost:3002/"');

    if (hasErrors) {
        console.error("[Config] Your config has invalid values. Fix them first https://docs.spacebar.chat/setup/server/configuration");
        console.error("[Config] Hint: if you're just testing with bundle (`npm run start`), you can set all endpoint URLs to [proto]://localhost:3001");
        process.exit(1);
    } else console.log("[Config] Configuration validated successfully.");
}