/*jshint esversion: 6 */
const nThen = require("nthen");

const Util = require("./common-util");
const mkEvent = Util.mkEvent;

const Core = require("./commands/core");
const Admin = require("./commands/admin-rpc");
const Pinning = require("./commands/pin-rpc");
const Quota = require("./commands/quota");
const Block = require("./commands/block");
const Metadata = require("./commands/metadata");
const Channel = require("./commands/channel");
const Upload = require("./commands/upload");

var RPC = module.exports;

const Store = require("../storage/file");
const BlobStore = require("../storage/blob");

const UNAUTHENTICATED_CALLS = [
    'GET_FILE_SIZE',
    'GET_METADATA',
    'GET_MULTIPLE_FILE_SIZE',
    'IS_CHANNEL_PINNED',
    'IS_NEW_CHANNEL',
    'GET_DELETED_PADS',
    'WRITE_PRIVATE_MESSAGE',
];

var isUnauthenticatedCall = function (call) {
    return UNAUTHENTICATED_CALLS.indexOf(call) !== -1;
};

const AUTHENTICATED_CALLS = [
    'COOKIE',
    'RESET',
    'PIN',
    'UNPIN',
    'GET_HASH',
    'GET_TOTAL_SIZE',
    'UPDATE_LIMITS',
    'GET_LIMIT',
    'UPLOAD_STATUS',
    'UPLOAD_COMPLETE',
    'OWNED_UPLOAD_COMPLETE',
    'UPLOAD_CANCEL',
    'EXPIRE_SESSION',
    'TRIM_OWNED_CHANNEL_HISTORY',
    'CLEAR_OWNED_CHANNEL',
    'REMOVE_OWNED_CHANNEL',
    'REMOVE_PINS',
    'TRIM_PINS',
    'WRITE_LOGIN_BLOCK',
    'REMOVE_LOGIN_BLOCK',
    'ADMIN',
    'SET_METADATA'
];

var isAuthenticatedCall = function (call) {
    return AUTHENTICATED_CALLS.indexOf(call) !== -1;
};

var isUnauthenticateMessage = function (msg) {
    return msg && msg.length === 2 && isUnauthenticatedCall(msg[0]);
};

var handleUnauthenticatedMessage = function (Env, msg, respond, Server) {
    Env.Log.silly('LOG_RPC', msg[0]);
    switch (msg[0]) {
        case 'GET_FILE_SIZE':
            return void Pinning.getFileSize(Env, msg[1], function (e, size) {
                Env.WARN(e, msg[1]);
                respond(e, [null, size, null]);
            });
        case 'GET_METADATA':
            return void Metadata.getMetadata(Env, msg[1], function (e, data) {
                Env.WARN(e, msg[1]);
                respond(e, [null, data, null]);
            });
        case 'GET_MULTIPLE_FILE_SIZE': // XXX not actually used on the client?
            return void Pinning.getMultipleFileSize(Env, msg[1], function (e, dict) {
                if (e) {
                    Env.WARN(e, dict);
                    return respond(e);
                }
                respond(e, [null, dict, null]);
            });
        case 'GET_DELETED_PADS':
            return void Pinning.getDeletedPads(Env, msg[1], function (e, list) {
                if (e) {
                    Env.WARN(e, msg[1]);
                    return respond(e);
                }
                respond(e, [null, list, null]);
            });
        case 'IS_CHANNEL_PINNED':
            return void Pinning.isChannelPinned(Env, msg[1], function (isPinned) {
                respond(null, [null, isPinned, null]);
            });
        case 'IS_NEW_CHANNEL':
            return void Channel.isNewChannel(Env, msg[1], function (e, isNew) {
                respond(e, [null, isNew, null]);
            });
        case 'WRITE_PRIVATE_MESSAGE':
            return void Channel.writePrivateMessage(Env, msg[1], Server, function (e, output) {
                respond(e, output);
            });
        default:
            Env.Log.warn("UNSUPPORTED_RPC_CALL", msg);
            return respond('UNSUPPORTED_RPC_CALL', msg);
    }
};

const AUTHENTICATED_USER_TARGETED = {
    RESET: Pinning.resetUserPins,
    PIN: Pinning.pinChannel,
    UNPIN: Pinning.unpinChannel,
    CLEAR_OWNED_CHANNEL: Channel.clearOwnedChannel,
    REMOVE_OWNED_CHANNEL: Channel.removeOwnedChannel,
    UPLOAD_STATUS: Upload.status,
    UPLOAD: Upload.upload,
    UPLOAD_COMPLETE: Upload.complete,
    UPLOAD_CANCEL: Upload.cancel,
    OWNED_UPLOAD_COMPLETE: Upload.complete_owned,
};

const AUTHENTICATED_USER_SCOPED = {
    GET_HASH: Pinning.getHash,
    GET_TOTAL_SIZE: Pinning.getTotalSize,
    UPDATE_LIMITS: Quota.updateLimits,
    GET_LIMIT: Pinning.getLimit,
    EXPIRE_SESSION: Core.expireSessionAsync,
    REMOVE_PINS: Pinning.removePins,
    TRIM_PINS: Pinning.trimPins,
    SET_METADATA: Metadata.setMetadata,
};

var handleAuthenticatedMessage = function (Env, map) {
    var msg = map.msg;
    var safeKey = map.safeKey;
    var publicKey = map.publicKey;
    var Respond = map.Respond;
    var Server = map.Server;

    var TYPE = msg[0];

    Env.Log.silly('LOG_RPC', TYPE);

    if (typeof(AUTHENTICATED_USER_TARGETED[TYPE]) === 'function') {
        return void AUTHENTICATED_USER_TARGETED[TYPE](Env, safeKey, msg[1], function (e, value) {
            Env.WARN(e, value);
            return void Respond(e, value);
        });
    }

    if (typeof(AUTHENTICATED_USER_SCOPED[TYPE]) === 'function') {
        return void AUTHENTICATED_USER_SCOPED[TYPE](Env, safeKey, function (e, value) {
            if (e) {
                Env.WARN(e, safeKey);
                return void Respond(e);
            }
            Respond(e, value);
        });
    }

    switch (msg[0]) {
        case 'COOKIE': return void Respond(void 0);
        case 'TRIM_OWNED_CHANNEL_HISTORY':
            return void Channel.removeOwnedChannelHistory(Env, msg[1], publicKey, msg[2], function (e) { // XXX USER_TARGETED_DOUBLE
                if (e) { return void Respond(e); }
                Respond(void 0, 'OK');
            });
        case 'WRITE_LOGIN_BLOCK':
            return void Block.writeLoginBlock(Env, msg[1], function (e) { // XXX SPECIAL
                if (e) {
                    Env.WARN(e, 'WRITE_LOGIN_BLOCK');
                    return void Respond(e);
                }
                Respond(e);
            });
        case 'REMOVE_LOGIN_BLOCK':
            return void Block.removeLoginBlock(Env, msg[1], function (e) { // XXX SPECIAL
                if (e) {
                    Env.WARN(e, 'REMOVE_LOGIN_BLOCK');
                    return void Respond(e);
                }
                Respond(e);
            });
        case 'ADMIN':
            return void Admin.command(Env, Server, safeKey, msg[1], function (e, result) { // XXX SPECIAL
                if (e) {
                    Env.WARN(e, result);
                    return void Respond(e);
                }
                Respond(void 0, result);
            });
        default:
            return void Respond('UNSUPPORTED_RPC_CALL', msg);
    }
};

var rpc = function (Env, Server, data, respond) {
    if (!Array.isArray(data)) {
        Env.Log.debug('INVALID_ARG_FORMET', data);
        return void respond('INVALID_ARG_FORMAT');
    }

    if (!data.length) {
        return void respond("INSUFFICIENT_ARGS");
    } else if (data.length !== 1) {
        Env.Log.debug('UNEXPECTED_ARGUMENTS_LENGTH', data);
    }

    var msg = data[0].slice(0);

    if (!Array.isArray(msg)) {
        return void respond('INVALID_ARG_FORMAT');
    }

    if (isUnauthenticateMessage(msg)) {
        return handleUnauthenticatedMessage(Env, msg, respond, Server);
    }

    var signature = msg.shift();
    var publicKey = msg.shift();

    // make sure a user object is initialized in the cookie jar
    if (publicKey) {
        Core.getSession(Env.Sessions, publicKey);
    } else {
        Env.Log.debug("NO_PUBLIC_KEY_PROVIDED", publicKey);
    }

    var cookie = msg[0];
    if (!Core.isValidCookie(Env.Sessions, publicKey, cookie)) {
        // no cookie is fine if the RPC is to get a cookie
        if (msg[1] !== 'COOKIE') {
            return void respond('NO_COOKIE');
        }
    }

    var serialized = JSON.stringify(msg);

    if (!(serialized && typeof(publicKey) === 'string')) {
        return void respond('INVALID_MESSAGE_OR_PUBLIC_KEY');
    }

    if (isAuthenticatedCall(msg[1])) {
        if (Core.checkSignature(Env, serialized, signature, publicKey) !== true) {
            return void respond("INVALID_SIGNATURE_OR_PUBLIC_KEY");
        }
    } else if (msg[1] !== 'UPLOAD') {
        Env.Log.warn('INVALID_RPC_CALL', msg[1]);
        return void respond("INVALID_RPC_CALL");
    }

    var safeKey = Util.escapeKeyCharacters(publicKey);
    /*  If you have gotten this far, you have signed the message with the
        public key which you provided.

        We can safely modify the state for that key

        OR it's an unauthenticated call, which must not modify the state
        for that key in a meaningful way.
    */

    // discard validated cookie from message
    msg.shift();

    var Respond = function (e, msg) {
        var session = Env.Sessions[safeKey];
        var token = session? session.tokens.slice(-1)[0]: '';
        var cookie = Core.makeCookie(token).join('|');
        respond(e ? String(e): e, [cookie].concat(typeof(msg) !== 'undefined' ?msg: []));
    };

    if (typeof(msg) !== 'object' || !msg.length) {
        return void Respond('INVALID_MSG');
    }

    handleAuthenticatedMessage(Env, {
        msg: msg,
        safeKey: safeKey,
        publicKey: publicKey,
        Respond: Respond,
        Server: Server,
    });
};

RPC.create = function (config, cb) {
    var Log = config.log;

    // load pin-store...
    Log.silly('LOADING RPC MODULE');

    var keyOrDefaultString = function (key, def) {
        return typeof(config[key]) === 'string'? config[key]: def;
    };

    var WARN = function (e, output) {
        if (e && output) {
            Log.warn(e, {
                output: output,
                message: String(e),
                stack: new Error(e).stack,
            });
        }
    };

    var Env = {
        historyKeeper: config.historyKeeper,
        intervals: config.intervals || {},
        defaultStorageLimit: config.defaultStorageLimit,
        maxUploadSize: config.maxUploadSize || (20 * 1024 * 1024),
        Sessions: {},
        paths: {},
        msgStore: config.store,
        pinStore: undefined,
        pinnedPads: {},
        evPinnedPadsReady: mkEvent(true),
        limits: {},
        admins: [],
        Log: Log,
        WARN: WARN,
        flushCache: config.flushCache,
        adminEmail: config.adminEmail,
        allowSubscriptions: config.allowSubscriptions,
        myDomain: config.myDomain,
        mySubdomain: config.mySubdomain,
        customLimits: config.customLimits,
        domain: config.domain // XXX
    };

    try {
        Env.admins = (config.adminKeys || []).map(function (k) {
            k = k.replace(/\/+$/, '');
            var s = k.split('/');
            return s[s.length-1];
        });
    } catch (e) {
        console.error("Can't parse admin keys. Please update or fix your config.js file!");
    }

    var Sessions = Env.Sessions;
    var paths = Env.paths;
    var pinPath = paths.pin = keyOrDefaultString('pinPath', './pins');
    paths.block = keyOrDefaultString('blockPath', './block');
    paths.data = keyOrDefaultString('filePath', './datastore');
    paths.staging = keyOrDefaultString('blobStagingPath', './blobstage');
    paths.blob = keyOrDefaultString('blobPath', './blob');

    var updateLimitDaily = function () {
        Quota.updateLimits(Env, undefined, function (e) {
            if (e) {
                WARN('limitUpdate', e);
            }
        });
    };
    Quota.applyCustomLimits(Env);
    updateLimitDaily();
    Env.intervals.dailyLimitUpdate = setInterval(updateLimitDaily, 24*3600*1000);

    Pinning.loadChannelPins(Env);

    nThen(function (w) {
        Store.create({
            filePath: pinPath,
        }, w(function (s) {
            Env.pinStore = s;
        }));
        BlobStore.create({
            blobPath: config.blobPath,
            blobStagingPath: config.blobStagingPath,
            archivePath: config.archivePath,
            getSession: function (safeKey) {
                return Core.getSession(Sessions, safeKey);
            },
        }, w(function (err, blob) {
            if (err) { throw new Error(err); }
            Env.blobStore = blob;
        }));
    }).nThen(function () {
        cb(void 0, function (Server, data, respond) {
            try {
                return rpc(Env, Server, data, respond);
            } catch (e) {
                console.log("Error from RPC with data " + JSON.stringify(data));
                console.log(e.stack);
            }
        });
        // expire old sessions once per minute
        Env.intervals.sessionExpirationInterval = setInterval(function () {
            Core.expireSessions(Sessions);
        }, Core.SESSION_EXPIRATION_TIME);
    });
};