esphome:
  name: uart-mock-modbus-lambda-write

host:
api:
logger:
  level: VERBOSE

external_components:
  - source:
      type: local
      path: EXTERNAL_COMPONENT_PATH

# Dummy uart entry to satisfy modbus's DEPENDENCIES = ["uart"]
# The actual UART bus used is the uart_mock component below
uart:
  baud_rate: 115200
  port: /dev/null

uart_mock:
  - id: virtual_uart_server
    baud_rate: 9600
    auto_start: true
    debug:
    on_tx:
      - then:
          - uart_mock.inject_rx:
              id: virtual_uart_controller
              data: !lambda return data;
  - id: virtual_uart_controller
    baud_rate: 9600
    auto_start: true
    debug:
    on_tx:
      - then:
          - uart_mock.inject_rx:
              id: virtual_uart_server
              data: !lambda return data;

globals:
  - id: reg30
    type: uint16_t
    initial_value: "0"

modbus:
  - uart_id: virtual_uart_server
    id: virtual_modbus_server
    role: server
  - uart_id: virtual_uart_controller
    id: virtual_modbus_controller
    role: client
    turnaround_time: 10ms

modbus_controller:
  - address: 1
    modbus_id: virtual_modbus_controller
    id: modbus_controller_1
    update_interval: 1s

modbus_server:
  - address: 1
    modbus_id: virtual_modbus_server
    id: modbus_server_1
    registers:
      - address: 0x30
        value_type: U_WORD
        read_lambda: return id(reg30);
        write_lambda: id(reg30) = x; return true;

# A COIL-type switch (assumed_state, write-only) whose write_lambda ignores its own coil type and instead
# drives a HOLDING-REGISTER write on the mock server through the entity itself: `item` IS the command, so
# item->write_single_register() sends a register write from a coil entity (cross-type). Returning nothing
# (an empty optional) tells the write path the lambda already dispatched the frame - no default coil write.
switch:
  - platform: modbus_controller
    modbus_controller_id: modbus_controller_1
    name: "cross_switch"
    register_type: coil
    address: 0x00
    assumed_state: true
    write_lambda: |-
      item->write_single_register(0x30, x ? 1234 : 0);
      return {};

sensor:
  - platform: modbus_controller
    modbus_controller_id: modbus_controller_1
    name: "reg_30"
    address: 0x30
    register_type: holding
    value_type: U_WORD

button:
  - platform: template
    name: "Start Scenario"
    id: start_scenario_btn
    # This test does not have anything to start (mock is autostart)