`timescale 1ns/1ps
`include "uvm_macros.svh"
import uvm_pkg :: *;

`define ADDR_WIDTH_IN_BITS 8
`define DATA_WIDTH_IN_BITS 8

//-----------------------------------------------------------------------------
// Interface
//-----------------------------------------------------------------------------
interface my_interface(input logic clk,
                       input logic rstn /* Active Low Reset */);
  bit valid;
  logic [`ADDR_WIDTH_IN_BITS - 1 : 0] start_addr;
  reg [`DATA_WIDTH_IN_BITS - 1 : 0] data_reg;
  wire [`DATA_WIDTH_IN_BITS - 1 : 0] data;
  int unsigned length_in_bytes;

  assign data = data_reg;
endinterface : my_interface

typedef virtual my_interface my_vif;
typedef class my_agent;

//-----------------------------------------------------------------------------
// Agent Configuration Class
//-----------------------------------------------------------------------------
class my_agent_cfg extends uvm_object;
  // virtual interface
  my_vif vif;
  // The length of time, in ps, that reset will stay active
  int unsigned reset_time_ps = 10;
  // Minimum length of payload data
  int unsigned min_payload_length = 5;
  // Maximum length of payload data
  int unsigned max_payload_length = 100;
  uvm_active_passive_enum is_active = UVM_ACTIVE;

  `uvm_object_utils_begin(my_agent_cfg)
    `uvm_field_enum(uvm_active_passive_enum, is_active, UVM_DEFAULT)
    `uvm_field_int(reset_time_ps,      UVM_DEFAULT | UVM_DEC)
    `uvm_field_int(min_payload_length, UVM_DEFAULT | UVM_DEC)
    `uvm_field_int(max_payload_length, UVM_DEFAULT | UVM_DEC)
  `uvm_object_utils_end

  function new(string name="my_agent_cfg");
    super.new(name);
  endfunction : new

  function void is_valid();
    if (max_payload_length < min_payload_length) begin
      `uvm_error(get_name(),
      $sformatf("Value of max_payload_length is shall be greater or equal to value of min_payload_length, configured values of max_payload_length:%0d, min_payload_length:%0d",
      max_payload_length, min_payload_length))
    end
    if (reset_time_ps <= 0) begin
      `uvm_error(get_name(), $sformatf("reset_time_ps shall be greater than 0"))
    end
  endfunction : is_valid
endclass : my_agent_cfg

//-----------------------------------------------------------------------------
// Sequence Item Class
//-----------------------------------------------------------------------------
class my_seq_item extends uvm_sequence_item;
  // Random varialbes
  rand logic [`ADDR_WIDTH_IN_BITS - 1 : 0] start_addr;
  rand logic [`DATA_WIDTH_IN_BITS - 1 : 0] data[];
  rand int unsigned payload_length;
  // Non random variables
  my_agent_cfg cfg;

  `uvm_object_utils_begin(my_seq_item)
    `uvm_field_int       (start_addr,     UVM_DEFAULT | UVM_HEX)
    `uvm_field_int       (payload_length, UVM_DEFAULT | UVM_DEC)
    `uvm_field_array_int (data,           UVM_DEFAULT | UVM_HEX)
  `uvm_object_utils_end

  constraint length_cn {
    payload_length inside {[cfg.min_payload_length : cfg.max_payload_length]};
    data.size == payload_length;
  }
  constraint order_cn {
    solve payload_length before data;
  }

  function new(string name="my_seq_item");
    super.new(name);
  endfunction : new

  function string convert2string();
    convert2string = $sformatf("start_addr:%0h, payload_length:%0d, data[0]:%0h, data[%0d]:%0h",
    start_addr, payload_length, data[0], payload_length-1, data[payload_length-1]);
  endfunction : convert2string
endclass : my_seq_item