//! Tests for `ModbusRelayController`
//!
//! These tests cover T025a through T025e of the implementation plan.
//! Note: These tests require mocking or a test Modbus server since they test
//! real TCP connections and Modbus protocol interactions.

use super::*;

#[cfg(test)]
mod t025a_connection_setup_tests {
    use super::*;

    /// T025a Test 1: `new()` with valid config connects successfully
    ///
    /// This test verifies that `ModbusRelayController::new()` can establish
    /// a connection to a valid Modbus TCP server.
    ///
    /// NOTE: This test requires a running Modbus TCP server at 127.0.0.1:5020
    /// or should be modified to use a mock server. Mark with #[ignore] if no server available.
    #[tokio::test]
    #[ignore = "Requires running Modbus TCP server"]
    async fn test_new_with_valid_config_connects_successfully() {
        // Arrange: Use localhost test server
        let host = "127.0.0.1";
        let port = 5020; // Test Modbus TCP port
        let slave_id = 1;
        let timeout_secs = 5;

        // Act: Attempt to create controller
        let result = ModbusRelayController::new(host, port, slave_id, timeout_secs).await;

        // Assert: Connection should succeed
        assert!(
            result.is_ok(),
            "Expected successful connection to test Modbus server, got error: {:?}",
            result.err()
        );
    }

    /// T025a Test 2: `new()` with invalid host returns `ConnectionError`
    ///
    /// This test verifies that `ModbusRelayController::new()` returns a proper
    /// `ConnectionError` when given an invalid hostname.
    #[tokio::test]
    async fn test_new_with_invalid_host_returns_connection_error() {
        // Arrange: Use invalid host format
        let host = "not a valid host!!!";
        let port = 502;
        let slave_id = 1;
        let timeout_secs = 5;

        // Act: Attempt to create controller
        let result = ModbusRelayController::new(host, port, slave_id, timeout_secs).await;

        // Assert: Should return ConnectionError
        assert!(result.is_err(), "Expected ConnectionError for invalid host");

        let error = result.unwrap_err();
        assert!(
            matches!(
                error,
                crate::domain::relay::controller::ControllerError::ConnectionError(_)
            ),
            "Expected ControllerError::ConnectionError, got {error:?}"
        );
    }

    /// T025a Test 3: `new()` with unreachable port returns `ConnectionError`
    ///
    /// This test verifies that attempting to connect to a closed/unreachable port
    /// results in a `ConnectionError`. Uses localhost port 1 (closed) for instant
    /// "connection refused" error without waiting for TCP timeout.
    #[tokio::test]
    async fn test_new_with_unreachable_host_returns_connection_error() {
        // Arrange: Use localhost with a closed port (port 1 is typically closed)
        // This gives instant "connection refused" instead of waiting for TCP timeout
        let host = "127.0.0.1";
        let port = 1; // Closed port for instant connection failure
        let slave_id = 1;
        let timeout_secs = 1;

        // Act: Attempt to create controller
        let result = ModbusRelayController::new(host, port, slave_id, timeout_secs).await;

        // Assert: Should return ConnectionError
        assert!(
            result.is_err(),
            "Expected ConnectionError for unreachable host"
        );
    }

    /// T025a Test 4: `new()` stores correct `timeout_duration`
    ///
    /// This test verifies that the `timeout_secs` parameter is correctly
    /// stored in the controller instance.
    ///
    /// NOTE: This test requires access to internal state or a working connection
    /// to verify timeout behavior. Mark with #[ignore] if no server available.
    #[tokio::test]
    #[ignore = "Requires running Modbus TCP server or refactoring to expose timeout"]
    async fn test_new_stores_correct_timeout_duration() {
        // Arrange
        let host = "127.0.0.1";
        let port = 5020;
        let slave_id = 1;
        let timeout_secs = 10;

        // Act
        let controller = ModbusRelayController::new(host, port, slave_id, timeout_secs)
            .await
            .expect("Failed to create controller");

        // Assert: Verify timeout is stored correctly
        // Note: This requires either:
        // 1. A getter method for timeout_duration, or
        // 2. Testing timeout behavior by triggering an actual timeout, or
        // 3. Refactoring to make timeout_duration accessible for testing
        //
        // For now, this is a placeholder that documents the requirement
        drop(controller);
    }
}

#[cfg(test)]
mod t025b_read_coils_timeout_tests {
    // Note: These tests require access to private method read_coils_with_timeout()
    // Options:
    // 1. Make the method pub(crate) for testing
    // 2. Test indirectly through public RelayController methods
    // 3. Use a test-only feature flag to expose for testing
    //
    // For now, we'll test through the public interface (read_relay_state)

    use super::*;
    use crate::domain::relay::{
        controller::{ControllerError, RelayController},
        types::RelayId,
    };

    /// T025b Test 1: `read_coils_with_timeout()` returns coil values on success
    ///
    /// This test verifies that reading coils succeeds when the Modbus server
    /// responds correctly.
    ///
    /// NOTE: Tests through `read_relay_state()` public interface
    #[tokio::test]
    #[ignore = "Requires running Modbus TCP server with known state"]
    async fn test_read_coils_returns_coil_values_on_success() {
        // Arrange: Connect to test server
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 5)
            .await
            .expect("Failed to connect to test server");

        let relay_id = RelayId::new(1).expect("Valid relay ID");

        // Act: Read relay state (internally calls read_coils_with_timeout)
        let result = controller.read_relay_state(relay_id).await;

        // Assert: Should succeed with a valid state
        assert!(
            result.is_ok(),
            "Expected successful coil read, got error: {:?}",
            result.err()
        );
    }

    /// T025b Test 2: `read_coils_with_timeout()` returns Timeout error when operation exceeds timeout
    ///
    /// This test verifies that the timeout mechanism works correctly.
    ///
    /// NOTE: Requires either a slow/non-responsive Modbus server or mocking
    #[tokio::test]
    #[ignore = "Requires slow/non-responsive Modbus server or mocking"]
    async fn test_read_coils_returns_timeout_on_slow_response() {
        // Arrange: Connect with very short timeout
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 1)
            .await
            .expect("Failed to connect");

        let relay_id = RelayId::new(1).expect("Valid relay ID");

        // Act: Attempt to read (server should be configured to delay response)
        let result = controller.read_relay_state(relay_id).await;

        // Assert: Should return Timeout error
        assert!(result.is_err(), "Expected timeout error");

        if let Err(ControllerError::Timeout(secs)) = result {
            assert_eq!(secs, 1, "Timeout duration should match configured value");
        } else {
            panic!("Expected ControllerError::Timeout, got {result:?}");
        }
    }

    /// T025b Test 3: `read_coils_with_timeout()` returns `ConnectionError` on `io::Error`
    ///
    /// This test verifies that IO errors are properly wrapped as `ConnectionError`.
    #[tokio::test]
    #[ignore = "Requires Modbus server that drops connections"]
    async fn test_read_coils_returns_connection_error_on_io_error() {
        // Arrange: Connect to server that will drop connection
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 5)
            .await
            .expect("Failed to connect");

        // Server should be configured to drop connection after initial connect
        let relay_id = RelayId::new(1).expect("Valid relay ID");

        // Act: Attempt to read after connection is dropped
        let result = controller.read_relay_state(relay_id).await;

        // Assert: Should return ConnectionError
        assert!(result.is_err(), "Expected connection error");
        assert!(
            matches!(result, Err(ControllerError::ConnectionError(_))),
            "Expected ConnectionError, got {result:?}"
        );
    }

    /// T025b Test 4: `read_coils_with_timeout()` returns `ModbusException` on protocol error
    ///
    /// This test verifies that Modbus protocol exceptions are properly handled.
    #[tokio::test]
    #[ignore = "Requires Modbus server that returns exception codes"]
    async fn test_read_coils_returns_modbus_exception_on_protocol_error() {
        // Arrange: Connect to server configured to return Modbus exception
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 5)
            .await
            .expect("Failed to connect");

        // Server should be configured to return exception for this relay ID
        let relay_id = RelayId::new(1).expect("Valid relay ID");

        // Act: Attempt to read (should trigger Modbus exception)
        let result = controller.read_relay_state(relay_id).await;

        // Assert: Should return ModbusException error
        assert!(result.is_err(), "Expected Modbus exception");
        assert!(
            matches!(result, Err(ControllerError::ModbusException(_))),
            "Expected ModbusException, got {result:?}"
        );
    }
}

#[cfg(test)]
mod t025c_write_single_coil_timeout_tests {
    use super::*;
    use crate::domain::relay::{
        controller::{ControllerError, RelayController},
        types::{RelayId, RelayState},
    };

    /// T025c Test 1: `write_single_coil_with_timeout()` succeeds for valid write
    ///
    /// This test verifies that writing to a coil succeeds when the Modbus server
    /// responds correctly.
    ///
    /// NOTE: Tests through `write_relay_state()` public interface
    #[tokio::test]
    #[ignore = "Requires running Modbus TCP server"]
    async fn test_write_single_coil_succeeds_for_valid_write() {
        // Arrange: Connect to test server
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 5)
            .await
            .expect("Failed to connect to test server");

        let relay_id = RelayId::new(1).expect("Valid relay ID");
        let state = RelayState::On;

        // Act: Write relay state (internally calls write_single_coil_with_timeout)
        let result = controller.write_relay_state(relay_id, state).await;

        // Assert: Should succeed
        assert!(
            result.is_ok(),
            "Expected successful coil write, got error: {:?}",
            result.err()
        );
    }

    /// T025c Test 2: `write_single_coil_with_timeout()` returns Timeout on slow device
    ///
    /// This test verifies that write operations properly timeout.
    #[tokio::test]
    #[ignore = "Requires slow/non-responsive Modbus server"]
    async fn test_write_single_coil_returns_timeout_on_slow_device() {
        // Arrange: Connect with very short timeout
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 1)
            .await
            .expect("Failed to connect");

        let relay_id = RelayId::new(1).expect("Valid relay ID");
        let state = RelayState::On;

        // Act: Attempt to write (server should be configured to delay response)
        let result = controller.write_relay_state(relay_id, state).await;

        // Assert: Should return Timeout error
        assert!(result.is_err(), "Expected timeout error");

        if let Err(ControllerError::Timeout(secs)) = result {
            assert_eq!(secs, 1, "Timeout duration should match configured value");
        } else {
            panic!("Expected ControllerError::Timeout, got {result:?}");
        }
    }

    /// T025c Test 3: `write_single_coil_with_timeout()` returns appropriate error on failure
    ///
    /// This test verifies that various write failures are properly handled.
    #[tokio::test]
    #[ignore = "Requires Modbus server configured for error testing"]
    async fn test_write_single_coil_returns_error_on_failure() {
        // Arrange: Connect to test server
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 5)
            .await
            .expect("Failed to connect");

        let relay_id = RelayId::new(1).expect("Valid relay ID");
        let state = RelayState::On;

        // Act: Attempt to write (server should be configured to return error)
        let result = controller.write_relay_state(relay_id, state).await;

        // Assert: Should return an error (ConnectionError or ModbusException)
        assert!(result.is_err(), "Expected error from write operation");
    }
}

#[cfg(test)]
mod t025d_read_relay_state_tests {
    use super::*;
    use crate::domain::relay::{
        controller::RelayController,
        types::{RelayId, RelayState},
    };

    /// T025d Test 1: `read_relay_state(RelayId(1))` returns On when coil is true
    ///
    /// This test verifies that a true coil value is correctly converted to `RelayState::On`.
    #[tokio::test]
    #[ignore = "Requires Modbus server with relay 1 set to On"]
    async fn test_read_state_returns_on_when_coil_is_true() {
        // Arrange: Connect to test server with relay 1 in On state
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 5)
            .await
            .expect("Failed to connect to test server");

        let relay_id = RelayId::new(1).expect("Valid relay ID");

        // Act: Read relay state
        let result = controller.read_relay_state(relay_id).await;

        // Assert: Should return On state
        assert!(result.is_ok(), "Failed to read relay state");
        assert_eq!(result.unwrap(), RelayState::On, "Expected relay to be On");
    }

    /// T025d Test 2: `read_relay_state(RelayId(1))` returns Off when coil is false
    ///
    /// This test verifies that a false coil value is correctly converted to `RelayState::Off`.
    #[tokio::test]
    #[ignore = "Requires Modbus server with relay 1 set to Off"]
    async fn test_read_state_returns_off_when_coil_is_false() {
        // Arrange: Connect to test server with relay 1 in Off state
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 5)
            .await
            .expect("Failed to connect to test server");

        let relay_id = RelayId::new(1).expect("Valid relay ID");

        // Act: Read relay state
        let result = controller.read_relay_state(relay_id).await;

        // Assert: Should return Off state
        assert!(result.is_ok(), "Failed to read relay state");
        assert_eq!(result.unwrap(), RelayState::Off, "Expected relay to be Off");
    }

    /// T025d Test 3: `read_relay_state()` propagates `ControllerError` from helper
    ///
    /// This test verifies that errors from `read_coils_with_timeout` are properly propagated.
    #[tokio::test]
    #[ignore = "Requires Modbus server configured to return errors"]
    async fn test_read_state_propagates_controller_error() {
        // Arrange: Connect to test server
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 5)
            .await
            .expect("Failed to connect to test server");

        // Server should be configured to return error for this relay
        let relay_id = RelayId::new(1).expect("Valid relay ID");

        // Act: Attempt to read relay state
        let result = controller.read_relay_state(relay_id).await;

        // Assert: Should propagate error
        assert!(
            result.is_err(),
            "Expected error to be propagated from helper"
        );
    }

    /// T025d Test 4: `read_relay_state()` correctly maps `RelayId` to `ModbusAddress`
    ///
    /// This test verifies that relay IDs are correctly converted to 0-based Modbus addresses.
    #[tokio::test]
    #[ignore = "Requires Modbus server with specific relay states"]
    async fn test_read_state_correctly_maps_relay_id_to_modbus_address() {
        // Arrange: Connect to test server with known relay states
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 5)
            .await
            .expect("Failed to connect to test server");

        // Test multiple relays to verify address mapping (RelayId 1-8 → Modbus 0-7)
        for relay_num in 1..=8 {
            let relay_id = RelayId::new(relay_num).expect("Valid relay ID");

            // Act: Read relay state
            let result = controller.read_relay_state(relay_id).await;

            // Assert: Should succeed for all valid relay IDs
            assert!(result.is_ok(), "Failed to read relay {relay_num} state");
        }
    }
}

#[cfg(test)]
mod t025e_write_relay_state_tests {
    use super::*;
    use crate::domain::relay::{
        controller::RelayController,
        types::{RelayId, RelayState},
    };

    /// T025e Test 1: `write_relay_state(RelayId(1)`, `RelayState::On`) writes true to coil
    ///
    /// This test verifies that `RelayState::On` is correctly converted to a true coil value.
    #[tokio::test]
    #[ignore = "Requires Modbus server that can verify written values"]
    async fn test_write_state_on_writes_true_to_coil() {
        // Arrange: Connect to test server
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 5)
            .await
            .expect("Failed to connect to test server");

        let relay_id = RelayId::new(1).expect("Valid relay ID");
        let state = RelayState::On;

        // Act: Write On state
        let write_result = controller.write_relay_state(relay_id, state).await;

        // Assert: Write should succeed
        assert!(
            write_result.is_ok(),
            "Failed to write relay state: {:?}",
            write_result.err()
        );

        // Verify by reading back
        let read_result = controller.read_relay_state(relay_id).await;
        assert!(read_result.is_ok(), "Failed to read back relay state");
        assert_eq!(
            read_result.unwrap(),
            RelayState::On,
            "Relay should be On after writing On state"
        );
    }

    /// T025e Test 2: `write_relay_state(RelayId(1)`, `RelayState::Off`) writes false to coil
    ///
    /// This test verifies that `RelayState::Off` is correctly converted to a false coil value.
    #[tokio::test]
    #[ignore = "Requires Modbus server that can verify written values"]
    async fn test_write_state_off_writes_false_to_coil() {
        // Arrange: Connect to test server
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 5)
            .await
            .expect("Failed to connect to test server");

        let relay_id = RelayId::new(1).expect("Valid relay ID");
        let state = RelayState::Off;

        // Act: Write Off state
        let write_result = controller.write_relay_state(relay_id, state).await;

        // Assert: Write should succeed
        assert!(
            write_result.is_ok(),
            "Failed to write relay state: {:?}",
            write_result.err()
        );

        // Verify by reading back
        let read_result = controller.read_relay_state(relay_id).await;
        assert!(read_result.is_ok(), "Failed to read back relay state");
        assert_eq!(
            read_result.unwrap(),
            RelayState::Off,
            "Relay should be Off after writing Off state"
        );
    }

    /// T025e Test 3: `write_relay_state()` correctly maps `RelayId` to `ModbusAddress`
    ///
    /// This test verifies that relay IDs are correctly converted when writing.
    #[tokio::test]
    #[ignore = "Requires Modbus server"]
    async fn test_write_state_correctly_maps_relay_id_to_modbus_address() {
        // Arrange: Connect to test server
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 5)
            .await
            .expect("Failed to connect to test server");

        // Test writing to all relay IDs to verify address mapping
        for relay_num in 1..=8 {
            let relay_id = RelayId::new(relay_num).expect("Valid relay ID");

            // Act: Write to relay
            let result = controller.write_relay_state(relay_id, RelayState::On).await;

            // Assert: Should succeed for all valid relay IDs
            assert!(
                result.is_ok(),
                "Failed to write to relay {}: {:?}",
                relay_num,
                result.err()
            );
        }
    }

    /// T025e Test 4: `write_relay_state()` can toggle relays between On and Off
    ///
    /// This test verifies that relays can be toggled multiple times.
    #[tokio::test]
    #[ignore = "Requires Modbus server"]
    async fn test_write_state_can_toggle_relay_multiple_times() {
        // Arrange: Connect to test server
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 5)
            .await
            .expect("Failed to connect to test server");

        let relay_id = RelayId::new(1).expect("Valid relay ID");

        // Act & Assert: Toggle relay multiple times
        for expected_state in [
            RelayState::On,
            RelayState::Off,
            RelayState::On,
            RelayState::Off,
        ] {
            let write_result = controller.write_relay_state(relay_id, expected_state).await;
            assert!(
                write_result.is_ok(),
                "Failed to write state {expected_state:?}"
            );

            let read_result = controller.read_relay_state(relay_id).await;
            assert!(read_result.is_ok(), "Failed to read state back");
            assert_eq!(
                read_result.unwrap(),
                expected_state,
                "Relay state should match written value"
            );
        }
    }
}

#[cfg(test)]
mod write_all_states_validation_tests {
    use super::*;

    /// Test: `write_all_states()` returns `InvalidInput` when given 0 states
    #[tokio::test]
    #[ignore = "Requires Modbus server"]
    async fn test_write_all_states_with_empty_vector_returns_invalid_input() {
        // Arrange: Connect to test server
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 5)
            .await
            .expect("Failed to connect to test server");

        // Act: Attempt to write with empty vector
        let result = controller.write_all_states(vec![]).await;

        // Assert: Should return InvalidInput error
        assert!(result.is_err(), "Expected error for empty states vector");
        assert!(
            matches!(result.unwrap_err(), ControllerError::InvalidInput(_)),
            "Expected InvalidInput error variant"
        );
    }

    /// Test: `write_all_states()` returns `InvalidInput` when given 7 states (too few)
    #[tokio::test]
    #[ignore = "Requires Modbus server"]
    async fn test_write_all_states_with_7_states_returns_invalid_input() {
        // Arrange: Connect to test server
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 5)
            .await
            .expect("Failed to connect to test server");

        // Act: Attempt to write with 7 states (missing one)
        let states = vec![RelayState::On; 7];
        let result = controller.write_all_states(states).await;

        // Assert: Should return InvalidInput error with descriptive message
        assert!(result.is_err(), "Expected error for 7 states");
        match result.unwrap_err() {
            ControllerError::InvalidInput(msg) => {
                assert!(
                    msg.contains("Expected 8"),
                    "Error message should mention expected count"
                );
                assert!(
                    msg.contains('7'),
                    "Error message should mention actual count"
                );
            }
            other => panic!("Expected InvalidInput, got {other:?}"),
        }
    }

    /// Test: `write_all_states()` returns `InvalidInput` when given 9 states (too many)
    #[tokio::test]
    #[ignore = "Requires Modbus server"]
    async fn test_write_all_states_with_9_states_returns_invalid_input() {
        // Arrange: Connect to test server
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 5)
            .await
            .expect("Failed to connect to test server");

        // Act: Attempt to write with 9 states (one extra)
        let states = vec![RelayState::Off; 9];
        let result = controller.write_all_states(states).await;

        // Assert: Should return InvalidInput error with descriptive message
        assert!(result.is_err(), "Expected error for 9 states");
        match result.unwrap_err() {
            ControllerError::InvalidInput(msg) => {
                assert!(
                    msg.contains("Expected 8"),
                    "Error message should mention expected count"
                );
                assert!(
                    msg.contains('9'),
                    "Error message should mention actual count"
                );
            }
            other => panic!("Expected InvalidInput, got {other:?}"),
        }
    }

    /// Test: `write_all_states()` succeeds with exactly 8 states
    #[tokio::test]
    #[ignore = "Requires Modbus server"]
    async fn test_write_all_states_with_8_states_succeeds() {
        // Arrange: Connect to test server
        let controller = ModbusRelayController::new("127.0.0.1", 5020, 1, 5)
            .await
            .expect("Failed to connect to test server");

        // Act: Write with exactly 8 states
        let states = vec![RelayState::On; 8];
        let result = controller.write_all_states(states).await;

        // Assert: Should succeed
        assert!(
            result.is_ok(),
            "Expected success for 8 states, got: {:?}",
            result.err()
        );
    }
}