"use strict";

import Matrix from "matrix-js-sdk";

var MatrixClientPeg = require("./MatrixClientPeg");
var SignupStages = require("./SignupStages");
var dis = require("./dispatcher");
var q = require("q");
var url = require("url");

const EMAIL_STAGE_TYPE = "m.login.email.identity";

/**
 * A base class for common functionality between Registration and Login e.g.
 * storage of HS/IS URLs.
 */
class Signup {
    constructor(hsUrl, isUrl, opts) {
        this._hsUrl = hsUrl;
        this._isUrl = isUrl;
        this._defaultDeviceDisplayName = opts.defaultDeviceDisplayName;
    }

    getHomeserverUrl() {
        return this._hsUrl;
    }

    getIdentityServerUrl() {
        return this._isUrl;
    }

    setHomeserverUrl(hsUrl) {
        this._hsUrl = hsUrl;
    }

    setIdentityServerUrl(isUrl) {
        this._isUrl = isUrl;
    }

    /**
     * Get a temporary MatrixClient, which can be used for login or register
     * requests.
     */
    _createTemporaryClient() {
        return Matrix.createClient({
            baseUrl: this._hsUrl,
            idBaseUrl: this._isUrl,
        });
    }
}

/**
 * Registration logic class
 * This exists for the lifetime of a user's attempt to register an account,
 * so if their registration attempt fails for whatever reason and they
 * try again, call register() on the same instance again.
 *
 * TODO: parts of this overlap heavily with InteractiveAuth in the js-sdk. It
 * would be nice to make use of that rather than rolling our own version of it.
 */
class Register extends Signup {
    constructor(hsUrl, isUrl, opts) {
        super(hsUrl, isUrl, opts);
        this.setStep("START");
        this.data = null; // from the server
        // random other stuff (e.g. query params, NOT params from the server)
        this.params = {};
        this.credentials = null;
        this.activeStage = null;
        this.registrationPromise = null;
        // These values MUST be undefined else we'll send "username: null" which
        // will error on Synapse rather than having the key absent.
        this.username = undefined; // desired
        this.email = undefined; // desired
        this.password = undefined; // desired
    }

    setClientSecret(secret) {
        this.params.clientSecret = secret;
    }

    setSessionId(sessionId) {
        this.params.sessionId = sessionId;
    }

    setRegistrationUrl(regUrl) {
        this.params.registrationUrl = regUrl;
    }

    setIdSid(idSid) {
        this.params.idSid = idSid;
    }

    setGuestAccessToken(token) {
        this.guestAccessToken = token;
    }

    getStep() {
        return this._step;
    }

    getCredentials() {
        return this.credentials;
    }

    getServerData() {
        return this.data || {};
    }

    getPromise() {
        return this.registrationPromise;
    }

    setStep(step) {
        this._step = 'Register.' + step;
        // TODO:
        // It's a shame this is going to the global dispatcher, we only really
        // want things which have an instance of this class to be able to add
        // listeners...
        console.log("Dispatching 'registration_step_update' for step %s", this._step);
        dis.dispatch({
            action: "registration_step_update"
        });
    }

    /**
     * Starts the registration process from the first stage
     */
    register(formVals) {
        var {username, password, email} = formVals;
        this.email = email;
        this.username = username;
        this.password = password;
        const client = this._createTemporaryClient();
        this.activeStage = null;

        // If there hasn't been a client secret set by this point,
        // generate one for this session. It will only be used if
        // we do email verification, but far simpler to just make
        // sure we have one.
        // We re-use this same secret over multiple calls to register
        // so that the identity server can honour the sendAttempt
        // parameter and not re-send email unless we actually want
        // another mail to be sent.
        if (!this.params.clientSecret) {
            this.params.clientSecret = client.generateClientSecret();
        }
        return this._tryRegister(client);
    }

    _tryRegister(client, authDict, poll_for_success) {
        var self = this;

        var bindEmail;

        if (this.username && this.password) {
            // only need to bind_email when sending u/p - sending it at other
            // times clobbers the u/p resulting in M_MISSING_PARAM (password)
            bindEmail = true;
        }

        // TODO need to figure out how to send the device display name to /register.
        return client.register(
            this.username, this.password, this.params.sessionId, authDict, bindEmail,
            this.guestAccessToken
        ).then(function(result) {
            self.credentials = result;
            self.setStep("COMPLETE");
            return result; // contains the credentials
        }, function(error) {
            if (error.httpStatus === 401) {
                if (error.data && error.data.flows) {
                    // Remember the session ID from the server:
                    // Either this is our first 401 in which case we need to store the
                    // session ID for future calls, or it isn't in which case this
                    // is just a no-op since it ought to be the same (or if it isn't,
                    // we should use the latest one from the server in any case).
                    self.params.sessionId = error.data.session;
                    self.data = error.data || {};
                    var flow = self.chooseFlow(error.data.flows);

                    if (flow) {
                        console.log("Active flow => %s", JSON.stringify(flow));
                        var flowStage = self.firstUncompletedStage(flow);
                        if (!self.activeStage || flowStage != self.activeStage.type) {
                            return self._startStage(client, flowStage).catch(function(err) {
                                self.setStep('START');
                                throw err;
                            });
                        }
                    }
                }
                if (poll_for_success) {
                    return q.delay(2000).then(function() {
                        return self._tryRegister(client, authDict, poll_for_success);
                    });
                } else {
                    throw new Error("Authorisation failed!");
                }
            } else {
                if (error.errcode === 'M_USER_IN_USE') {
                    throw new Error("Username in use");
                } else if (error.errcode == 'M_INVALID_USERNAME') {
                    throw new Error("User names may only contain alphanumeric characters, underscores or dots!");
                } else if (error.httpStatus >= 400 && error.httpStatus < 500) {
                    throw new Error(`Registration failed! (${error.httpStatus})`);
                } else if (error.httpStatus >= 500 && error.httpStatus < 600) {
                    throw new Error(
                        `Server error during registration! (${error.httpStatus})`
                    );
                } else if (error.name == "M_MISSING_PARAM") {
                    // The HS hasn't remembered the login params from
                    // the first try when the login email was sent.
                    throw new Error(
                        "This home server does not support resuming registration."
                    );
                }
            }
        });
    }

    firstUncompletedStage(flow) {
        for (var i = 0; i < flow.stages.length; ++i) {
            if (!this.hasCompletedStage(flow.stages[i])) {
                return flow.stages[i];
            }
        }
    }

    hasCompletedStage(stageType) {
        var completed = (this.data || {}).completed || [];
        return completed.indexOf(stageType) !== -1;
    }

    _startStage(client, stageName) {
        var self = this;
        this.setStep(`STEP_${stageName}`);
        var StageClass = SignupStages[stageName];
        if (!StageClass) {
            // no idea how to handle this!
            throw new Error("Unknown stage: " + stageName);
        }

        var stage = new StageClass(client, this);
        this.activeStage = stage;
        return stage.complete().then(function(request) {
            if (request.auth) {
                console.log("Stage %s is returning an auth dict", stageName);
                return self._tryRegister(client, request.auth, request.poll_for_success);
            }
            else {
                // never resolve the promise chain. This is for things like email auth
                // which display a "check your email" message and relies on the
                // link in the email to actually register you.
                console.log("Waiting for external action.");
                return q.defer().promise;
            }
        });
    }

    chooseFlow(flows) {
        // If the user gave us an email then we want to pick an email
        // flow we can do, else any other flow.
        var emailFlow = null;
        var otherFlow = null;
        flows.forEach(function(flow) {
            var flowHasEmail = false;
            for (var stageI = 0; stageI < flow.stages.length; ++stageI) {
                var stage = flow.stages[stageI];

                if (!SignupStages[stage]) {
                    // we can't do this flow, don't have a Stage impl.
                    return;
                }

                if (stage === EMAIL_STAGE_TYPE) {
                    flowHasEmail = true;
                }
            }

            if (flowHasEmail) {
                emailFlow = flow;
            } else {
                otherFlow = flow;
            }
        });

        if (this.email || this.hasCompletedStage(EMAIL_STAGE_TYPE)) {
            // we've been given an email or we've already done an email part
            return emailFlow;
        } else {
            return otherFlow;
        }
    }

    recheckState() {
        // We've been given a bunch of data from a previous register step,
        // this only happens for email auth currently. It's kinda ming we need
        // to know this though. A better solution would be to ask the stages if
        // they are ready to do something rather than accepting that we know about
        // email auth and its internals.
        this.params.hasEmailInfo = (
            this.params.clientSecret && this.params.sessionId && this.params.idSid
        );

        if (this.params.hasEmailInfo) {
            const client = this._createTemporaryClient();
            this.registrationPromise = this._startStage(client, EMAIL_STAGE_TYPE);
        }
        return this.registrationPromise;
    }

    tellStage(stageName, data) {
        if (this.activeStage && this.activeStage.type === stageName) {
            console.log("Telling stage %s about something..", stageName);
            this.activeStage.onReceiveData(data);
        }
    }
}


class Login extends Signup {
    constructor(hsUrl, isUrl, fallbackHsUrl, opts) {
        super(hsUrl, isUrl, opts);
        this._fallbackHsUrl = fallbackHsUrl;
        this._currentFlowIndex = 0;
        this._flows = [];
    }

    getFlows() {
        var self = this;
        var client = this._createTemporaryClient();
        return client.loginFlows().then(function(result) {
            self._flows = result.flows;
            self._currentFlowIndex = 0;
            // technically the UI should display options for all flows for the
            // user to then choose one, so return all the flows here.
            return self._flows;
        });
    }

    chooseFlow(flowIndex) {
        this._currentFlowIndex = flowIndex;
    }

    getCurrentFlowStep() {
        // technically the flow can have multiple steps, but no one does this
        // for login so we can ignore it.
        var flowStep = this._flows[this._currentFlowIndex];
        return flowStep ? flowStep.type : null;
    }

    loginAsGuest() {
        var client = this._createTemporaryClient();
        return client.registerGuest({
            body: {
                initial_device_display_name: this._defaultDeviceDisplayName,
            },
        }).then((creds) => {
            return {
                userId: creds.user_id,
                deviceId: creds.device_id,
                accessToken: creds.access_token,
                homeserverUrl: this._hsUrl,
                identityServerUrl: this._isUrl,
                guest: true
            };
        }, (error) => {
            if (error.httpStatus === 403) {
                error.friendlyText = "Guest access is disabled on this Home Server.";
            } else {
                error.friendlyText = "Failed to register as guest: " + error.data;
            }
            throw error;
        });
    }

    loginViaPassword(username, pass) {
        var self = this;
        var isEmail = username.indexOf("@") > 0;
        var loginParams = {
            password: pass,
            initial_device_display_name: this._defaultDeviceDisplayName,
        };
        if (isEmail) {
            loginParams.medium = 'email';
            loginParams.address = username;
        } else {
            loginParams.user = username;
        }

        var client = this._createTemporaryClient();
        return client.login('m.login.password', loginParams).then(function(data) {
            return q({
                homeserverUrl: self._hsUrl,
                identityServerUrl: self._isUrl,
                userId: data.user_id,
                deviceId: data.device_id,
                accessToken: data.access_token
            });
        }, function(error) {
            if (error.httpStatus == 400 && loginParams.medium) {
                error.friendlyText = (
                    'This Home Server does not support login using email address.'
                );
            }
            else if (error.httpStatus === 403) {
                error.friendlyText = (
                    'Incorrect username and/or password.'
                );
                if (self._fallbackHsUrl) {
                    var fbClient = Matrix.createClient({
                        baseUrl: self._fallbackHsUrl,
                        idBaseUrl: this._isUrl,
                    });

                    return fbClient.login('m.login.password', loginParams).then(function(data) {
                        return q({
                            homeserverUrl: self._fallbackHsUrl,
                            identityServerUrl: self._isUrl,
                            userId: data.user_id,
                            deviceId: data.device_id,
                            accessToken: data.access_token
                        });
                    }, function(fallback_error) {
                        // throw the original error
                        throw error;
                    });
                }
            }
            else {
                error.friendlyText = (
                    'There was a problem logging in. (HTTP ' + error.httpStatus + ")"
                );
            }
            throw error;
        });
    }

    redirectToCas() {
      var client = this._createTemporaryClient();
      var parsedUrl = url.parse(window.location.href, true);
      parsedUrl.query["homeserver"] = client.getHomeserverUrl();
      parsedUrl.query["identityServer"] = client.getIdentityServerUrl();
      var casUrl = client.getCasLoginUrl(url.format(parsedUrl));
      window.location.href = casUrl;
    }
}

module.exports.Register = Register;
module.exports.Login = Login;