/***********************************************************************************************************************************************************************
 * File Name: dashboard.controller.js  (admin)
 * Type of Program: Controller
 * Description: Admin dashboard — users and groups stats + breakdowns.
 *
 * Author: rgrgogu
 * Date Created: Oct. 6, 2025
 ***********************************************************************************************************************************************************************/
const { Op, fn, col, literal } = require('sequelize');
const mdl_Users = require('../../models/users/users.mdl');
const { mdl_UserGroups, mdl_UserGroupMembers } = require('../../models/users/user_groups.mdl');

// ─── USERS DASHBOARD ──────────────────────────────────────────────────────────

exports.getUsersDashboard = async (req, res) => {
  try {
    const [
      totalUsers,
      activeUsers,
      verifiedUsers,
      archivedUsers,
      accTypeBreakdown,
      regTypeBreakdown,
    ] = await Promise.all([
      mdl_Users.count({ paranoid: false }),
      mdl_Users.count({ where: { is_active: true } }),
      mdl_Users.count({ where: { is_verified: true } }),
      mdl_Users.count({ where: { deletedAt: { [Op.ne]: null } }, paranoid: false }),
      mdl_Users.findAll({
        attributes: ['acc_type', [fn('COUNT', col('user_id')), 'count']],
        group: ['acc_type'],
        raw:   true,
      }),
      mdl_Users.findAll({
        attributes: ['reg_type', [fn('COUNT', col('user_id')), 'count']],
        group: ['reg_type'],
        raw:   true,
      }),
    ]);

    return res.status(200).json({
      status:  'success',
      message: 'Users dashboard data fetched.',
      data: {
        stats: [
          { key: 'total',    label: 'Total Users',    value: totalUsers },
          { key: 'active',   label: 'Active Users',   value: activeUsers },
          { key: 'inactive', label: 'Inactive Users', value: totalUsers - archivedUsers - activeUsers },
          { key: 'verified', label: 'Verified',       value: verifiedUsers },
          { key: 'archived', label: 'Archived',       value: archivedUsers },
        ],
        breakdowns: [
          {
            key:   'acc_type',
            label: 'By Account Type',
            data:  accTypeBreakdown.map((r) => ({ label: r.acc_type, value: parseInt(r.count, 10) })),
          },
          {
            key:   'reg_type',
            label: 'By Registration Type',
            data:  regTypeBreakdown.map((r) => ({ label: r.reg_type, value: parseInt(r.count, 10) })),
          },
        ],
      },
    });
  } catch (err) {
    console.error('[ADMIN][DASHBOARD][USERS]', err);
    return res.status(500).json({ status: 'error', message: 'Could not fetch users dashboard data.' });
  }
};

// ─── GROUPS DASHBOARD ─────────────────────────────────────────────────────────

exports.getGroupsDashboard = async (req, res) => {
  try {
    const [
      totalGroups,
      activeGroups,
      archivedGroups,
      emptyGroups,
      memberCountBreakdown,
    ] = await Promise.all([
      mdl_UserGroups.count({ paranoid: false }),
      mdl_UserGroups.count({ where: { is_active: true } }),
      mdl_UserGroups.count({ where: { deletedAt: { [Op.ne]: null } }, paranoid: false }),
      mdl_UserGroups.count({
        where:   { is_active: true },
        include: [{
          model:    mdl_UserGroupMembers,
          required: false,
          where:    { deletedAt: null },
        }],
        having:   literal('COUNT("UserGroupMembers"."user_id") = 0'),
        group:    ['UserGroup.group_id'],
        subQuery: false,
      }).catch(() => 0),
      mdl_UserGroupMembers.findAll({
        attributes: [
          'group_id',
          [fn('COUNT', col('user_id')), 'member_count'],
        ],
        where:   { deletedAt: null },
        include: [{
          model:      mdl_UserGroups,
          attributes: ['name'],
          where:      { is_active: true },
        }],
        group:   ['UserGroupMember.group_id', 'UserGroup.group_id', 'UserGroup.name'],
        order:   [[literal('member_count'), 'DESC']],
        limit:   10,
        raw:     true,
        nest:    true,
      }),
    ]);

    return res.status(200).json({
      status:  'success',
      message: 'Groups dashboard data fetched.',
      data: {
        stats: [
          { key: 'total',    label: 'Total Groups',    value: totalGroups },
          { key: 'active',   label: 'Active Groups',   value: activeGroups },
          { key: 'inactive', label: 'Inactive Groups', value: totalGroups - archivedGroups - activeGroups },
          { key: 'archived', label: 'Archived',        value: archivedGroups },
          { key: 'empty',    label: 'Empty Groups',    value: Array.isArray(emptyGroups) ? emptyGroups.length : emptyGroups },
        ],
        breakdowns: [
          {
            key:   'top_groups',
            label: 'Top Groups by Members',
            data:  memberCountBreakdown.map((r) => ({
              label: r.UserGroup?.name ?? `Group ${r.group_id}`,
              value: parseInt(r.member_count, 10),
            })),
          },
        ],
      },
    });
  } catch (err) {
    console.error('[ADMIN][DASHBOARD][GROUPS]', err);
    return res.status(500).json({ status: 'error', message: 'Could not fetch groups dashboard data.' });
  }
};