/***********************************************************************************************************************************************************************
 * File Name: user_groups.controller.js  (admin)
 * Type of Program: Controller
 * Description: Admin-level user group management — CRUD + membership.
 *
 * Author: rgrgogu
 * Date Created: Oct. 6, 2025
 ***********************************************************************************************************************************************************************/
const sequelize = require('../../config/db.config');
const { Op, Sequelize } = require('sequelize');

const mdl_Users        = require('../../models/users/users.mdl');
const { mdl_UserGroups, mdl_UserGroupMembers } = require('../../models/users/user_groups.mdl');

const R              = require('../../utils/response.util');
const { paginate }   = require('../../utils/paginate.util');

const { excludeAttributes: usersExclude, jsonbSchemas: usersSchemas }   = require('../../models/users/users.attributes');
const { excludeAttributes: groupExclude, jsonbSchemas: groupSchemas, computedAttributes: groupComputed } = require('../../models/users/user_groups.attributes');

const auditByFields = ['createdBy', 'updatedBy', 'deletedBy'];

// ─── GET ALL ──────────────────────────────────────────────────────────────────

exports.getGroups = async (req, res) => {
  try {
    const result = await paginate(mdl_UserGroups, req, {
      excludeAttributes:  groupExclude,
      jsonbSchemas:       groupSchemas,
      computedAttributes: groupComputed,
      auditOptions:       { mdl_Users, parentAlias: 'UserGroup' },
    });

    return R.success(res, 'Groups retrieved.', result);
  } catch (err) {
    console.error('[ADMIN][GET GROUPS]', err);
    return R.error(res, 'Could not retrieve groups.', 500);
  }
};

// ─── GET ONE ──────────────────────────────────────────────────────────────────

exports.getGroup = async (req, res) => {
  try {
    const group = await mdl_UserGroups.findByPk(req.params.gid);
    if (!group) return R.error(res, 'Group not found.', 404);

    const members = await paginate(mdl_Users, req, {
      excludeAttributes: usersExclude,
      jsonbSchemas:      usersSchemas,
      jsonbColumn:       'personal_info',
      auditOptions:      { mdl_Users, parentAlias: 'User' },
      findOptions: {
        include: [{
          model:    mdl_UserGroupMembers,
          where:    { group_id: req.params.gid },
          attributes: [],
          required: true,
        }],
      },
    });

    return R.success(res, 'Group retrieved.', { group, members });
  } catch (err) {
    console.error('[ADMIN][GET GROUP]', err);
    return R.error(res, 'Could not retrieve group.', 500);
  }
};

// ─── CREATE ───────────────────────────────────────────────────────────────────

exports.createGroup = async (req, res) => {
  try {
    const { name, description } = req.body;
    if (!name) return R.error(res, 'Group name is required.', 400);

    const group = await mdl_UserGroups.create({
      name, description, createdBy: req.user.user_id,
    });

    return R.success(res, 'Group created.', group, 201);
  } catch (err) {
    console.error('[ADMIN][CREATE GROUP]', err);
    return R.error(res, 'Could not create group.', 500);
  }
};

// ─── UPDATE ───────────────────────────────────────────────────────────────────

exports.updateGroup = async (req, res) => {
  try {
    const group = await mdl_UserGroups.findByPk(req.params.gid);
    if (!group) return R.error(res, 'Group not found.', 404);

    const { name, description } = req.body;
    if (name        !== undefined) group.name        = name;
    if (description !== undefined) group.description = description;
    group.updatedBy = req.user.user_id;
    await group.save();

    return R.success(res, 'Group updated.', group);
  } catch (err) {
    console.error('[ADMIN][UPDATE GROUP]', err);
    return R.error(res, 'Could not update group.', 500);
  }
};

// ─── DEACTIVATE ───────────────────────────────────────────────────────────────

exports.deactivateGroup = async (req, res) => {
  try {
    const group = await mdl_UserGroups.findByPk(req.params.gid);
    if (!group)          return R.error(res, 'Group not found.', 404);
    if (!group.is_active) return R.error(res, 'Group is already deactivated.', 400);

    await group.update({ is_active: false, updatedBy: req.user.user_id, deletedBy: req.user.user_id });
    await group.destroy();

    return R.success(res, 'Group deactivated.');
  } catch (err) {
    console.error('[ADMIN][DEACTIVATE GROUP]', err);
    return R.error(res, 'Could not deactivate group.', 500);
  }
};

// ─── RESTORE ──────────────────────────────────────────────────────────────────

exports.restoreGroup = async (req, res) => {
  try {
    const group = await mdl_UserGroups.findOne({
      where: { group_id: req.params.gid }, paranoid: false,
    });
    if (!group)         return R.error(res, 'Group not found.', 404);
    if (group.is_active) return R.error(res, 'Group is already active.', 400);

    await group.restore();
    await group.update({ is_active: true, updatedBy: req.user.user_id, deletedBy: null });

    return R.success(res, 'Group restored.');
  } catch (err) {
    console.error('[ADMIN][RESTORE GROUP]', err);
    return R.error(res, 'Could not restore group.', 500);
  }
};

// ─── BULK DEACTIVATE ──────────────────────────────────────────────────────────

exports.bulkDeactivateGroups = async (req, res) => {
  try {
    const { ids } = req.body;
    if (!Array.isArray(ids) || !ids.length)
      return R.error(res, 'No group IDs provided.', 400);

    const groups = await mdl_UserGroups.findAll({ where: { group_id: ids } });
    if (!groups.length) return R.error(res, 'No groups found.', 404);

    const activeGroups = groups.filter((g) => g.is_active && !g.deletedAt);
    if (!activeGroups.length)
      return R.error(res, 'All selected groups are already deactivated.', 400);

    const activeIds = activeGroups.map((g) => g.group_id);

    await mdl_UserGroups.update(
      { is_active: false, deletedBy: req.user.user_id },
      { where: { group_id: activeIds } }
    );
    await mdl_UserGroups.destroy({ where: { group_id: activeIds } });

    return R.success(res, `${activeIds.length} group(s) deactivated successfully.`, {
      deactivated_ids: activeIds,
      skipped_ids:     ids.filter((id) => !activeIds.includes(id)),
    });
  } catch (err) {
    console.error('[ADMIN][BULK DEACTIVATE GROUPS]', err);
    return R.error(res, 'Could not deactivate groups.', 500);
  }
};

// ─── BULK RESTORE ─────────────────────────────────────────────────────────────

exports.bulkRestoreGroups = async (req, res) => {
  try {
    const { ids } = req.body;
    if (!Array.isArray(ids) || !ids.length)
      return R.error(res, 'No group IDs provided.', 400);

    const groups = await mdl_UserGroups.findAll({ where: { group_id: ids }, paranoid: false });
    if (!groups.length) return R.error(res, 'No groups found.', 404);

    const deletedGroups = groups.filter((g) => g.deletedAt);
    if (!deletedGroups.length)
      return R.error(res, 'All selected groups are already active.', 400);

    const deletedIds = deletedGroups.map((g) => g.group_id);

    await mdl_UserGroups.restore({ where: { group_id: deletedIds } });
    await mdl_UserGroups.update(
      { is_active: true, updatedBy: req.user.user_id, deletedBy: null },
      { where: { group_id: deletedIds }, paranoid: false }
    );

    return R.success(res, `${deletedIds.length} group(s) restored successfully.`, {
      restored_ids: deletedIds,
      skipped_ids:  ids.filter((id) => !deletedIds.includes(id)),
    });
  } catch (err) {
    console.error('[ADMIN][BULK RESTORE GROUPS]', err);
    return R.error(res, 'Could not restore groups.', 500);
  }
};

// ─── ARCHIVED ─────────────────────────────────────────────────────────────────

exports.getArchivedGroups = async (req, res) => {
  try {
    const result = await paginate(mdl_UserGroups, req, {
      excludeAttributes:  groupExclude,
      jsonbSchemas:       groupSchemas,
      computedAttributes: groupComputed,
      auditOptions:       { mdl_Users, parentAlias: 'UserGroup' },
      findOptions: {
        paranoid: false,
        where:    { deletedAt: { [Op.ne]: null }, is_active: false },
      },
    });

    return R.success(res, 'Archived groups retrieved.', result);
  } catch (err) {
    console.error('[ADMIN][GET ARCHIVED GROUPS]', err);
    return R.error(res, 'Could not retrieve archived groups.', 500);
  }
};

// ─── FIELD VALUES ─────────────────────────────────────────────────────────────

exports.getGroupFieldValues = async (req, res) => {
  try {
    const { field } = req.query;
    if (!field) return R.error(res, 'Field is required.', 400);

    const allowedFields = Object.keys(mdl_UserGroups.rawAttributes).filter(
      (f) => !['deletedAt'].includes(f)
    );
    const dateFields = ['createdAt', 'updatedAt', 'deletedAt'];

    if (!field.includes('.')) {
      if (!allowedFields.includes(field))
        return R.error(res, 'Invalid or restricted field.', 400);

      if (auditByFields.includes(field)) {
        const [rows] = await sequelize.query(`
          SELECT DISTINCT u."personal_info"->'name'->>'full_name' AS value
          FROM user_groups g
          JOIN users u ON u.user_id = g."${field}"
          WHERE g."${field}" IS NOT NULL
            AND u."personal_info"->'name'->>'full_name' IS NOT NULL
          ORDER BY value ASC
        `);
        return R.success(res, 'Field values retrieved.', rows.map((r) => r.value).filter(Boolean));
      }

      if (dateFields.includes(field)) {
        const results = await mdl_UserGroups.findAll({
          attributes: [[Sequelize.fn('DISTINCT', Sequelize.fn('DATE', Sequelize.col(field))), 'value']],
          where:     { [field]: { [Op.ne]: null } },
          order:     [[Sequelize.fn('DATE', Sequelize.col(field)), 'DESC']],
          paranoid:  false,
          raw:       true,
        });
        return R.success(res, 'Field values retrieved.', results.map((r) => r.value).filter(Boolean));
      }

      const results = await mdl_UserGroups.findAll({
        attributes: [[Sequelize.fn('DISTINCT', Sequelize.col(field)), 'value']],
        where:    { [field]: { [Op.ne]: null } },
        paranoid: false,
        raw:      true,
      });
      return R.success(res, 'Field values retrieved.', results.map((r) => r.value).filter(Boolean).sort());
    }

    return R.error(res, 'JSONB fields are not supported for groups.', 400);
  } catch (err) {
    console.error('[ADMIN][GET GROUP FIELD VALUES]', err);
    return R.error(res, 'Could not retrieve field values.', 500);
  }
};

// ─── MEMBERSHIP ───────────────────────────────────────────────────────────────

exports.getUsersNotInGroup = async (req, res) => {
  try {
    const { gid: group_id } = req.params;

    const members   = await mdl_UserGroupMembers.findAll({ where: { group_id }, attributes: ['user_id'] });
    const memberIds = members.map((m) => m.user_id);

    const users = await mdl_Users.findAll({
      where: { user_id: { [Op.notIn]: memberIds.length ? memberIds : [0] } },
      attributes: [
        'user_id',
        [Sequelize.literal(`("User"."personal_info"->'name'->>'full_name')`), 'full_name'],
      ],
    });

    return R.success(res, 'Users fetched.', users);
  } catch (err) {
    console.error('[ADMIN][GET USERS NOT IN GROUP]', err);
    return R.error(res, 'Could not fetch users.', 500);
  }
};

exports.getUsersInGroup = async (req, res) => {
  try {
    const { gid: group_id } = req.params;

    const group = await mdl_UserGroups.findByPk(group_id, {
      include: [{
        model:    mdl_Users,
        as:       'members',
        through:  { attributes: [] },
        attributes: [
          'user_id',
          [Sequelize.literal(`("members"."personal_info"->'name'->>'full_name')`), 'full_name'],
        ],
      }],
    });

    if (!group) return R.error(res, 'Group not found.', 404);
    return R.success(res, 'Group members fetched.', group.members);
  } catch (err) {
    console.error('[ADMIN][GET USERS IN GROUP]', err);
    return R.error(res, 'Could not fetch group members.', 500);
  }
};

exports.addUserToGroup = async (req, res) => {
  try {
    const { gid: group_id } = req.params;
    const { user_ids } = req.body;

    if (!Array.isArray(user_ids) || !user_ids.length)
      return R.error(res, 'No users provided.', 400);

    const existingUsers  = await mdl_Users.findAll({ where: { user_id: user_ids }, attributes: ['user_id'] });
    const existingIds    = existingUsers.map((u) => u.user_id);
    const notFound       = user_ids.filter((id) => !existingIds.includes(id));

    if (notFound.length)
      return R.error(res, `Users not found: ${notFound.join(', ')}`, 404);

    await mdl_UserGroupMembers.restore({ where: { user_id: user_ids, group_id } });
    await mdl_UserGroupMembers.update(
      { deletedBy: null, updatedBy: req.user.user_id },
      { where: { user_id: user_ids, group_id }, paranoid: false }
    );
    await mdl_UserGroupMembers.bulkCreate(
      user_ids.map((user_id) => ({ user_id, group_id, createdBy: req.user.user_id })),
      { ignoreDuplicates: true }
    );

    return R.success(res, 'Users added to group.');
  } catch (err) {
    console.error('[ADMIN][ADD USERS TO GROUP]', err);
    return R.error(res, 'Could not add users to group.', 500);
  }
};

exports.removeUserFromGroup = async (req, res) => {
  try {
    const { gid: group_id } = req.params;
    const { user_ids } = req.body;

    if (!Array.isArray(user_ids) || !user_ids.length)
      return R.error(res, 'No users provided.', 400);

    const existingMembers = await mdl_UserGroupMembers.findAll({
      where: { user_id: user_ids, group_id }, attributes: ['user_id'],
    });
    const existingIds = existingMembers.map((m) => m.user_id);
    const notFound    = user_ids.filter((id) => !existingIds.includes(id));

    if (notFound.length)
      return R.error(res, `Memberships not found for users: ${notFound.join(', ')}`, 404);

    await mdl_UserGroupMembers.update(
      { deletedBy: req.user.user_id },
      { where: { user_id: user_ids, group_id } }
    );
    await mdl_UserGroupMembers.destroy({ where: { user_id: user_ids, group_id } });

    return R.success(res, 'Users removed from group.');
  } catch (err) {
    console.error('[ADMIN][REMOVE USERS FROM GROUP]', err);
    return R.error(res, 'Could not remove users from group.', 500);
  }
};