const ldap = require('../util/ldapjs-extra');
const execFile = require('child_process').execFile;
const isProduction = require('vn-loopback/server/boot/isProduction');

/**
 * Summary of userAccountControl flags:
 * https://docs.microsoft.com/en-us/troubleshoot/windows-server/identity/useraccountcontrol-manipulate-account-properties
 */
const UserAccountControlFlags = {
    ACCOUNTDISABLE: 0x2,
    DONT_EXPIRE_PASSWD: 0x10000
};

module.exports = Self => {
    const shouldSync = isProduction();

    Self.getLinker = async function() {
        return await Self.findOne({
            fields: [
                'host',
                'adDomain',
                'adController',
                'adUser',
                'adPassword',
                'userDn',
                'verifyCert'
            ]
        });
    };

    Object.assign(Self.prototype, {
        async init() {
            const baseDn = this.adDomain
                .split('.')
                .map(part => `dc=${part}`)
                .join(',');
            const bindDn = `cn=${this.adUser},cn=Users,${baseDn}`;

            const adClient = ldap.createClient({
                url: `ldaps://${this.adController}:636`,
                tlsOptions: {rejectUnauthorized: this.verifyCert}
            });
            adClient.on('error', () => {});
            await adClient.bind(bindDn, this.adPassword);
            Object.assign(this, {
                adClient,
                fullUsersDn: `${this.userDn},${baseDn}`,
                bindDn
            });
        },

        async deinit() {
            await this.adClient.unbind();
        },

        async sambaTool(command, args = []) {
            let authArgs = [
                '--URL', `ldaps://${this.adController}`,
                '--simple-bind-dn', this.bindDn,
                '--password', this.adPassword
            ];
            if (!this.verifyCert)
                authArgs.push('--option', 'tls verify peer = no_check');

            const allArgs = [command].concat(
                args, authArgs
            );

            if (!shouldSync) return;
            return await new Promise((resolve, reject) => {
                execFile('samba-tool', allArgs, (err, stdout, stderr) => {
                    if (err)
                        reject(err);
                    else
                        resolve({stdout, stderr});
                });
            });
        },

        async getAdUser(userName) {
            const sambaUser = await this.adClient.searchOne(this.fullUsersDn, {
                scope: 'sub',
                attributes: [
                    'dn',
                    'userAccountControl',
                    'uidNumber',
                    'accountExpires',
                    'mail'
                ],
                filter: `(&(objectClass=user)(sAMAccountName=${userName}))`
            });
            if (sambaUser) {
                for (const intProp of ['uidNumber', 'userAccountControl']) {
                    if (sambaUser[intProp] != null)
                        sambaUser[intProp] = parseInt(sambaUser[intProp]);
                }
            }
            return sambaUser;
        },

        async syncUser(userName, info, password) {
            let sambaUser = await this.getAdUser(userName);
            let entry;

            if (info.hasAccount) {
                if (!sambaUser) {
                    await this.sambaTool('user', [
                        'create', userName,
                        '--userou', this.userDn,
                        '--random-password'
                    ]);
                    sambaUser = await this.getAdUser(userName);
                }
                if (password) {
                    await this.sambaTool('user', [
                        'setpassword', userName,
                        '--newpassword', password
                    ]);
                }

                entry = {
                    userAccountControl: (sambaUser.userAccountControl
                        | UserAccountControlFlags.DONT_EXPIRE_PASSWD)
                        & ~UserAccountControlFlags.ACCOUNTDISABLE,
                    uidNumber: info.uidNumber,
                    accountExpires: 0,
                    mail: info.corporateMail
                };
            } else if (sambaUser) {
                entry = {
                    userAccountControl: sambaUser.userAccountControl
                        | UserAccountControlFlags.ACCOUNTDISABLE
                };
                // eslint-disable-next-line no-console
                console.log(` -> User '${userName}' disabled on Samba`);
            }

            if (sambaUser && entry) {
                const changes = [];
                for (const prop in entry) {
                    if (sambaUser[prop] == entry[prop]) continue;
                    changes.push(new ldap.Change({
                        operation: 'replace',
                        modification: {
                            [prop]: entry[prop]
                        }
                    }));
                }
                if (changes.length && shouldSync)
                    await this.adClient.modify(sambaUser.dn, changes);
            }
        },

        /**
         * Gets Samba enabled users.
         *
         * @param {Set} usersToSync
         */
        async getUsers(usersToSync) {
            const LDAP_MATCHING_RULE_BIT_AND = '1.2.840.113556.1.4.803';
            const filter = `!(userAccountControl:${LDAP_MATCHING_RULE_BIT_AND}`
                + `:=${UserAccountControlFlags.ACCOUNTDISABLE})`;

            const opts = {
                scope: 'sub',
                attributes: ['sAMAccountName'],
                filter: `(&(objectClass=user)(${filter}))`
            };
            await this.adClient.searchForeach(this.fullUsersDn, opts,
                o => usersToSync.add(o.sAMAccountName));
        }
    });
};