'use strict';

exports = module.exports = {
    add,
    remove,
    get,
    getByName,

    update,
    setName,

    getWithMembers,
    list,
    listWithMembers,

    getMembers,
    setMembers,
    removeMember,
    isMember,

    setLocalMembership,
    resetSource,

    // exported for testing
    _getMembership: getMembership
};

const assert = require('assert'),
    BoxError = require('./boxerror.js'),
    constants = require('./constants.js'),
    database = require('./database.js'),
    safe = require('safetydance'),
    uuid = require('uuid');

const GROUPS_FIELDS = [ 'id', 'name', 'source' ].join(',');

// keep this in sync with validateUsername
function validateName(name) {
    assert.strictEqual(typeof name, 'string');

    if (name.length < 1) return new BoxError(BoxError.BAD_FIELD, 'name must be atleast 1 char');
    if (name.length >= 200) return new BoxError(BoxError.BAD_FIELD, 'name too long');

    if (constants.RESERVED_NAMES.indexOf(name) !== -1) return new BoxError(BoxError.BAD_FIELD, 'name is reserved');

    // need to consider valid LDAP characters here (e.g '+' is reserved)
    if (/[^a-zA-Z0-9.-]/.test(name)) return new BoxError(BoxError.BAD_FIELD, 'name can only contain alphanumerals, hyphen and dot');

    return null;
}

function validateSource(source) {
    assert.strictEqual(typeof source, 'string');

    if (source !== '' && source !== 'ldap') return new BoxError(BoxError.BAD_FIELD, 'source must be "" or "ldap"');

    return null;
}

async function add(group) {
    assert.strictEqual(typeof group, 'object');

    let { name, source } = group;

    name = name.toLowerCase(); // we store names in lowercase
    source = source || '';

    let error = validateName(name);
    if (error) throw error;

    error = validateSource(source);
    if (error) throw error;

    const id = `gid-${uuid.v4()}`;

    [error] = await safe(database.query('INSERT INTO userGroups (id, name, source) VALUES (?, ?, ?)', [ id, name, source ]));
    if (error && error.code === 'ER_DUP_ENTRY') throw new BoxError(BoxError.ALREADY_EXISTS, error);
    if (error) throw error;

    return { id, name, source };
}

async function remove(id) {
    assert.strictEqual(typeof id, 'string');

    // also cleanup the groupMembers table
    let queries = [];
    queries.push({ query: 'DELETE FROM groupMembers WHERE groupId = ?', args: [ id ] });
    queries.push({ query: 'DELETE FROM userGroups WHERE id = ?', args: [ id ] });

    const result = await database.transaction(queries);
    if (result[1].affectedRows !== 1) throw new BoxError(BoxError.NOT_FOUND, 'Group not found');
}

async function get(id) {
    assert.strictEqual(typeof id, 'string');

    const result = await database.query(`SELECT ${GROUPS_FIELDS} FROM userGroups WHERE id = ? ORDER BY name`, [ id ]);
    if (result.length === 0) return null;

    return result[0];
}

async function getByName(name) {
    assert.strictEqual(typeof name, 'string');

    const result = await database.query(`SELECT ${GROUPS_FIELDS} FROM userGroups WHERE name = ?`, [ name ]);
    if (result.length === 0) return null;

    return result[0];
}

async function getWithMembers(id) {
    assert.strictEqual(typeof id, 'string');

    const results = await database.query('SELECT ' + GROUPS_FIELDS + ',GROUP_CONCAT(groupMembers.userId) AS userIds ' +
        ' FROM userGroups LEFT OUTER JOIN groupMembers ON userGroups.id = groupMembers.groupId ' +
        ' WHERE userGroups.id = ? ' +
        ' GROUP BY userGroups.id', [ id ]);

    if (results.length === 0) return null;

    const result = results[0];
    result.userIds = result.userIds ? result.userIds.split(',') : [ ];

    return result;
}

async function list() {
    const results = await database.query('SELECT ' + GROUPS_FIELDS + ' FROM userGroups ORDER BY name');
    return results;
}

async function listWithMembers() {
    const results = await database.query('SELECT ' + GROUPS_FIELDS + ',GROUP_CONCAT(groupMembers.userId) AS userIds ' +
        ' FROM userGroups LEFT OUTER JOIN groupMembers ON userGroups.id = groupMembers.groupId ' +
        ' GROUP BY userGroups.id ORDER BY name');

    results.forEach(function (result) { result.userIds = result.userIds ? result.userIds.split(',') : [ ]; });
    return results;
}

async function getMembers(groupId) {
    assert.strictEqual(typeof groupId, 'string');

    const result = await database.query('SELECT userId FROM groupMembers WHERE groupId=?', [ groupId ]);

    return result.map(function (r) { return r.userId; });
}

async function getMembership(userId) {
    assert.strictEqual(typeof userId, 'string');

    const result = await database.query('SELECT groupId FROM groupMembers WHERE userId=? ORDER BY groupId', [ userId ]);

    return result.map(function (r) { return r.groupId; });
}

async function setLocalMembership(user, localGroupIds) {
    assert.strictEqual(typeof user, 'object'); // can be local or external
    assert(Array.isArray(localGroupIds));

    // ensure groups are actually local
    for (const groupId of localGroupIds) {
        const group = await get(groupId);
        if (!group) throw new BoxError(BoxError.NOT_FOUND, `Group ${groupId} not found`);
        if (group.source) throw new BoxError(BoxError.BAD_STATE, 'Cannot set members of external group');
    }

    const queries = [];
    // a remote user may already be part of some external groups. do not clear those because remote groups are non-editable
    queries.push({ query: 'DELETE FROM groupMembers WHERE userId = ? AND groupId IN (SELECT id FROM userGroups WHERE source = ?)', args: [ user.id, '' ] });
    for (const gid of localGroupIds) {
        queries.push({ query: 'INSERT INTO groupMembers (groupId, userId) VALUES (? , ?)', args: [ gid, user.id ] });
    }

    const [error] = await safe(database.transaction(queries));
    if (error && error.code === 'ER_NO_REFERENCED_ROW_2') throw new BoxError(BoxError.NOT_FOUND, 'Group not found');
    if (error && error.code === 'ER_DUP_ENTRY') throw new BoxError(BoxError.CONFLICT, 'Already member');
    if (error) throw error;
}

async function setMembers(group, userIds, options) {
    assert.strictEqual(typeof group, 'object');
    assert(Array.isArray(userIds));
    assert.strictEqual(typeof options, 'object');

    if (!options.skipSourceCheck && group.source === 'ldap') throw new BoxError(BoxError.BAD_STATE, 'Cannot set members of external group');

    const queries = [];
    queries.push({ query: 'DELETE FROM groupMembers WHERE groupId = ?', args: [ group.id ] });
    for (let i = 0; i < userIds.length; i++) {
        queries.push({ query: 'INSERT INTO groupMembers (groupId, userId) VALUES (?, ?)', args: [ group.id, userIds[i] ] });
    }

    const [error] = await safe(database.transaction(queries));
    if (error && error.code === 'ER_NO_REFERENCED_ROW_2') throw new BoxError(BoxError.NOT_FOUND, 'Group not found');
    if (error && error.code === 'ER_DUP_ENTRY') throw new BoxError(BoxError.CONFLICT, 'Duplicate member in list');
    if (error) throw error;
}

async function removeMember(groupId, userId) {
    assert.strictEqual(typeof groupId, 'string');
    assert.strictEqual(typeof userId, 'string');

    const result = await database.query('DELETE FROM groupMembers WHERE groupId = ? AND userId = ?', [ groupId, userId ]);
    if (result.affectedRows !== 1) throw new BoxError(BoxError.NOT_FOUND, 'Group not found');
}

async function isMember(groupId, userId) {
    assert.strictEqual(typeof groupId, 'string');
    assert.strictEqual(typeof userId, 'string');

    const result = await database.query('SELECT 1 FROM groupMembers WHERE groupId=? AND userId=?', [ groupId, userId ]);
    return result.length !== 0;
}

async function update(id, data) {
    assert.strictEqual(typeof id, 'string');
    assert(data && typeof data === 'object');

    if ('name' in data) {
        assert.strictEqual(typeof data.name, 'string');
        data.name = data.name.toLowerCase();
        const error = validateName(data.name);
        if (error) throw error;
    }

    if ('source' in data) {
        assert.strictEqual(typeof data.source, 'string');
        const error = validateSource(data.source);
        if (error) throw error;
    }

    const args = [];
    const fields = [];
    for (const k in data) {
        if (k === 'name' || k === 'source') {
            fields.push(k + ' = ?');
            args.push(data[k]);
        }
    }
    args.push(id);

    const [updateError, result] = await safe(database.query('UPDATE userGroups SET ' + fields.join(', ') + ' WHERE id = ?', args));
    if (updateError && updateError.code === 'ER_DUP_ENTRY' && updateError.sqlMessage.indexOf('userGroups_name') !== -1) throw new BoxError(BoxError.ALREADY_EXISTS, 'name already exists');
    if (updateError) throw updateError;
    if (result.affectedRows !== 1) throw new BoxError(BoxError.NOT_FOUND, 'Group not found');
}

async function setName(group, name) {
    assert.strictEqual(typeof group, 'object');
    assert.strictEqual(typeof name, 'string');

    if (group.source === 'ldap') throw new BoxError(BoxError.BAD_STATE, 'Cannot set name of external group');

    await update(group.id, { name });
}

async function resetSource() {
    await database.query('UPDATE userGroups SET source = ?', [ '' ]);
}