Update Data Usulan Dana

public function updateusulan_post()
    {
        $username    = trim($this->post('username'));
        $id          = $this->post('id');
        $reviewer_id = $this->post('reviewer_id');
        $dana        = $this->post('dana');

        if ($username == '') {
            $response = [
                'resp_error' => true,
                'resp_msg'   => 'Username Kosong.',
            ];
        } elseif ($id == '') {
            $response = [
                'resp_error' => true,
                'resp_msg'   => 'ID Proposal Kosong.',
            ];
        } elseif ($reviewer_id == '') {
            $response = [
                'resp_error' => true,
                'resp_msg'   => 'ID Reviewer Kosong.',
            ];
        } elseif ($dana == '' || $dana == 0) {
            $response = [
                'resp_error' => true,
                'resp_msg'   => 'Usulan Dana tidak boleh Kosong.',
            ];
        } else {
            // Cek Batasan Anggaran
            $dtProposal    = $this->db->get_where('lemlit_propose', array('propose_id' => $id))->row();
            $skim_id       = $dtProposal->skim_id;
            $dtBudget      = $this->db->get_where('lemlit_skim', array('skim_id' => $skim_id))->row();
            $budget        = $dtBudget->skim_budget;
            $budget_rupiah = number_format($budget, 0, '', ',');

            if ($dana > $budget) {
                $response = [
                    'resp_error' => true,
                    'resp_msg'   => 'Usulan Dana Melebihi Budget, Budget = ' . $budget_rupiah,
                ];
            } else {
                $data = array(
                    'usulan_dana'     => $dana,
                    'reviewer_update' => date('Y-m-d H:i:s'),
                );

                $this->db->where('reviewer_id', $reviewer_id);
                $this->db->update('lemlit_reviewer', $data);

                $response = [
                    'resp_error'    => false,
                    'usulan_rupiah' => number_format($dana, 0, '', ','),
                    'resp_msg'      => 'Update Data Usulan Reviewer Berhasil.',
                ];
            }
        }

        $this->response($response, 200);
    }