/*
Copyright 2019, 2021 The Matrix.org Foundation C.I.C.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

import * as fs from "fs";
import { load } from "js-yaml";
import { MatrixClient, LogService } from "matrix-bot-sdk";
import Config from "config";

/**
 * The configuration, as read from production.yaml
 *
 * See file default.yaml for the documentation on individual options.
 */
// The object is magically generated by external lib `config`
// from the file specified by `NODE_ENV`, e.g. production.yaml
// or harness.yaml.
export interface IConfig {
    homeserverUrl: string;
    rawHomeserverUrl: string;
    accessToken: string;
    pantalaimon: {
        use: boolean;
        username: string;
        password: string;
    };
    dataPath: string;
    acceptInvitesFromSpace: string;
    autojoinOnlyIfManager: boolean;
    recordIgnoredInvites: boolean;
    managementRoom: string;
    verboseLogging: boolean;
    logLevel: "DEBUG" | "INFO" | "WARN" | "ERROR";
    syncOnStartup: boolean;
    verifyPermissionsOnStartup: boolean;
    noop: boolean;
    protectedRooms: string[]; // matrix.to urls
    fasterMembershipChecks: boolean;
    automaticallyRedactForReasons: string[]; // case-insensitive globs
    protectAllJoinedRooms: boolean;
    /**
     * Backgrounded tasks: number of milliseconds to wait between the completion
     * of one background task and the start of the next one.
     */
    backgroundDelayMS: number;
    pollReports: boolean;
    /**
     * Whether or not new reports, received either by webapi or polling,
     * should be printed to our managementRoom.
     */
    displayReports: boolean;
    admin?: {
        enableMakeRoomAdminCommand?: boolean;
    }
    commands: {
        allowNoPrefix: boolean;
        additionalPrefixes: string[];
        confirmWildcardBan: boolean;
    };
    protections: {
        wordlist: {
            words: string[];
            minutesBeforeTrusting: number;
        };
    };
    health: {
        healthz: {
            enabled: boolean;
            port: number;
            address: string;
            endpoint: string;
            healthyStatus: number;
            unhealthyStatus: number;
        };
        // If specified, attempt to upload any crash statistics to sentry.
        sentry?: {
            dsn: string;

            // Frequency of performance monitoring.
            //
            // A number in [0.0, 1.0], where 0.0 means "don't bother with tracing"
            // and 1.0 means "trace performance at every opportunity".
            tracesSampleRate: number;
        };
    };
    web: {
        enabled: boolean;
        port: number;
        address: string;
        abuseReporting: {
            enabled: boolean;
        }
        ruleServer?: {
            enabled: boolean;
        }
    }

    /**
     * Config options only set at runtime. Try to avoid using the objects
     * here as much as possible.
     */
    RUNTIME: {
        client?: MatrixClient;
    };
}

const defaultConfig: IConfig = {
    homeserverUrl: "http://localhost:8008",
    rawHomeserverUrl: "http://localhost:8008",
    accessToken: "NONE_PROVIDED",
    pantalaimon: {
        use: false,
        username: "",
        password: "",
    },
    dataPath: "/data/storage",
    acceptInvitesFromSpace: '!noop:example.org',
    autojoinOnlyIfManager: false,
    recordIgnoredInvites: false,
    managementRoom: "!noop:example.org",
    verboseLogging: false,
    logLevel: "INFO",
    syncOnStartup: true,
    verifyPermissionsOnStartup: true,
    noop: false,
    protectedRooms: [],
    fasterMembershipChecks: false,
    automaticallyRedactForReasons: ["spam", "advertising"],
    protectAllJoinedRooms: false,
    backgroundDelayMS: 500,
    pollReports: false,
    displayReports: true,
    commands: {
        allowNoPrefix: false,
        additionalPrefixes: [],
        confirmWildcardBan: true,
    },
    protections: {
        wordlist: {
            words: [],
            minutesBeforeTrusting: 20
        }
    },
    health: {
        healthz: {
            enabled: false,
            port: 8080,
            address: "0.0.0.0",
            endpoint: "/healthz",
            healthyStatus: 200,
            unhealthyStatus: 418,
        },
    },
    web: {
        enabled: false,
        port: 8080,
        address: "localhost",
        abuseReporting: {
            enabled: false,
        },
        ruleServer: {
            enabled: false,
        },
    },

    // Needed to make the interface happy.
    RUNTIME: {
    },
};

export function getDefaultConfig(): IConfig {
    return Config.util.cloneDeep(defaultConfig);
}

/**
 * Grabs an explicit path provided for mjolnir's config from an arguments vector if provided, otherwise returns undefined.
 * @param argv An arguments vector sourced from `process.argv`.
 * @returns The path if one was provided or undefined.
 */
function configPathFromArguments(argv: string[]): undefined|string {
    const configOptionIndex = argv.findIndex(arg => arg === "--mjolnir-config");
    if (configOptionIndex > 0) {
        const configOptionPath = argv.at(configOptionIndex + 1);
        if (!configOptionPath) {
            throw new Error("No path provided with option --mjolnir-config");
        }
        return configOptionPath;
    } else {
        return;
    }
}

export function read(): IConfig {
    const explicitConfigPath = configPathFromArguments(process.argv);
    if (explicitConfigPath) {
        const content = fs.readFileSync(explicitConfigPath, "utf8");
        const parsed = load(content);
        return Config.util.extendDeep({}, defaultConfig, parsed);
    } else {
        const config = Config.util.extendDeep({}, defaultConfig, Config.util.toObject()) as IConfig;
        return config;
    }
}

/**
 * Provides a config for each newly provisioned mjolnir in appservice mode.
 * @param managementRoomId A room that has been created to serve as the mjolnir's management room for the owner.
 * @returns A config that can be directly used by the new mjolnir.
 */
export function getProvisionedMjolnirConfig(managementRoomId: string): IConfig {
    // These are keys that are allowed to be configured for provisioned mjolnirs.
    // We need a restricted set so that someone doesn't accidentally enable webservers etc
    // on every created Mjolnir, which would result in very confusing error messages.
    const allowedKeys = [
        "commands",
        "verboseLogging",
        "logLevel",
        "syncOnStartup",
        "verifyPermissionsOnStartup",
        "fasterMembershipChecks",
        "automaticallyRedactForReasons",
        "protectAllJoinedRooms",
        "backgroundDelayMS",
    ];
    const configTemplate = read(); // we use the standard bot config as a template for every provisioned mjolnir.
    const unusedKeys = Object.keys(configTemplate).filter(key => !allowedKeys.includes(key));
    if (unusedKeys.length > 0) {
        LogService.warn("config", "The config provided for provisioned mjolnirs contains keys which are not used by the appservice.", unusedKeys);
    }
    const config = Config.util.extendDeep(
        getDefaultConfig(),
        allowedKeys.reduce((existingConfig: any, key: string) => {
            return { ...existingConfig, [key]: configTemplate[key as keyof IConfig] }
        }, {})
    );

    config.managementRoom = managementRoomId;
    config.protectedRooms = [];
    return config;
}