// ABOUTME: Unit-Tests für Bragi-Protokoll Packet-Bau und Response-Parsing.
// ABOUTME: Testet build_packet, parse_response und BragiResponse-Methoden.

use corsairctl::bragi::protocol::*;
use corsairctl::error::CorsairError;

#[test]
fn build_get_packet_has_correct_header() {
    let packet = build_get_packet(ENDPOINT_HEADSET, 0x0F);

    assert_eq!(packet[0], 0x00, "Report ID");
    assert_eq!(packet[1], PROTOCOL_MARKER, "Protokoll-Marker");
    assert_eq!(packet[2], ENDPOINT_HEADSET, "Endpoint");
    assert_eq!(packet[3], CMD_GET, "Command");
    assert_eq!(packet[4], 0x0F, "Property");
}

#[test]
fn build_get_packet_is_zero_padded() {
    let packet = build_get_packet(ENDPOINT_RECEIVER, 0x13);

    assert_eq!(packet.len(), PACKET_SIZE);
    // Alle Bytes nach der Property sollten 0 sein
    for &byte in &packet[5..] {
        assert_eq!(byte, 0x00);
    }
}

#[test]
fn build_set_packet_includes_data() {
    let packet = build_set_packet(ENDPOINT_HEADSET, 0x03, &[0x00, 0x02]);

    assert_eq!(packet[3], CMD_SET, "Command");
    assert_eq!(packet[4], 0x03, "Property");
    assert_eq!(packet[5], 0x00, "Data byte 0");
    assert_eq!(packet[6], 0x02, "Data byte 1");
    // Rest sollte 0 sein
    assert_eq!(packet[7], 0x00);
}

#[test]
fn build_packet_total_size() {
    let packet = build_packet(0x08, 0x01, 0x03, &[0x00, 0x02]);
    assert_eq!(packet.len(), 65);
}

#[test]
fn parse_response_extracts_fields() {
    // Simulierte Response: [report_type, endpoint, command, status, data0, data1, ...]
    // Laut Protokoll-Doku: raw[0]=0x01 Report-Typ, raw[1]=Endpoint, raw[2]=Command, raw[3]=Status
    let mut raw = vec![0x01, RESPONSE_ENDPOINT_HEADSET, CMD_GET, STATUS_OK, 0xE8, 0x03];
    raw.resize(REPORT_SIZE, 0x00);

    let resp = parse_response(&raw).unwrap();

    assert_eq!(resp.endpoint, RESPONSE_ENDPOINT_HEADSET);
    assert_eq!(resp.command, CMD_GET);
    assert_eq!(resp.status, STATUS_OK);
    assert_eq!(resp.data[0], 0xE8);
    assert_eq!(resp.data[1], 0x03);
}

#[test]
fn parse_response_value_u16_little_endian() {
    let mut raw = vec![0x01, RESPONSE_ENDPOINT_HEADSET, CMD_GET, STATUS_OK, 0xE8, 0x03];
    raw.resize(REPORT_SIZE, 0x00);

    let resp = parse_response(&raw).unwrap();
    let value = resp.value_u16().unwrap();

    // 0xE8 | (0x03 << 8) = 232 + 768 = 1000
    assert_eq!(value, 1000);
}

#[test]
fn parse_response_value_u8() {
    let mut raw = vec![0x01, RESPONSE_ENDPOINT_HEADSET, CMD_GET, STATUS_OK, 0x03];
    raw.resize(REPORT_SIZE, 0x00);

    let resp = parse_response(&raw).unwrap();
    assert_eq!(resp.value_u8().unwrap(), 0x03);
}

#[test]
fn parse_response_error_f0() {
    let raw = vec![0x01, 0xF0, CMD_GET, STATUS_OK];

    let result = parse_response(&raw);
    assert!(result.is_err());
    match result.unwrap_err() {
        CorsairError::DeviceError { status } => assert_eq!(status, 0xF0),
        other => panic!("Erwarteter DeviceError, bekommen: {other:?}"),
    }
}

#[test]
fn parse_response_error_f1() {
    let raw = vec![0x01, 0xF1, CMD_GET, STATUS_OK];

    let result = parse_response(&raw);
    assert!(result.is_err());
    match result.unwrap_err() {
        CorsairError::DeviceError { status } => assert_eq!(status, 0xF1),
        other => panic!("Erwarteter DeviceError, bekommen: {other:?}"),
    }
}

#[test]
fn parse_response_too_short() {
    let raw = vec![0x01, 0x00];

    let result = parse_response(&raw);
    assert!(result.is_err());
    assert!(matches!(
        result.unwrap_err(),
        CorsairError::ResponseTooShort { .. }
    ));
}

#[test]
fn value_u16_on_empty_data_returns_error() {
    let raw = vec![0x01, RESPONSE_ENDPOINT_HEADSET, CMD_GET, STATUS_OK]; // Keine Daten-Bytes
    let resp = parse_response(&raw).unwrap();

    let result = resp.value_u16();
    assert!(result.is_err());
    assert!(matches!(
        result.unwrap_err(),
        CorsairError::ResponseTooShort { expected: 2, got: 0 }
    ));
}

#[test]
fn battery_level_full_is_1000_promille() {
    // Battery Level = 1000 (voll) → 0xE8, 0x03 LE
    let mut raw = vec![0x01, RESPONSE_ENDPOINT_HEADSET, CMD_GET, STATUS_OK, 0xE8, 0x03];
    raw.resize(REPORT_SIZE, 0x00);

    let resp = parse_response(&raw).unwrap();
    let promille = resp.value_u16().unwrap();
    assert_eq!(promille, 1000);
}

#[test]
fn battery_level_half_is_500_promille() {
    // Battery Level = 500 (50%) → 0xF4, 0x01 LE
    let mut raw = vec![0x01, RESPONSE_ENDPOINT_HEADSET, CMD_GET, STATUS_OK, 0xF4, 0x01];
    raw.resize(REPORT_SIZE, 0x00);

    let resp = parse_response(&raw).unwrap();
    let promille = resp.value_u16().unwrap();
    assert_eq!(promille, 500);
}

// --- Schritt 4: parse_response_validated Tests ---

#[test]
fn parse_response_validated_rejects_wrong_endpoint() {
    let mut raw = vec![0x01, RESPONSE_ENDPOINT_RECEIVER, CMD_GET, STATUS_OK, 0x00];
    raw.resize(REPORT_SIZE, 0x00);

    let result = parse_response_validated(&raw, Some(RESPONSE_ENDPOINT_HEADSET), None);
    assert!(result.is_err());
    assert!(matches!(
        result.unwrap_err(),
        CorsairError::UnexpectedResponse { .. }
    ));
}

#[test]
fn parse_response_validated_rejects_wrong_command() {
    let mut raw = vec![0x01, RESPONSE_ENDPOINT_HEADSET, CMD_SET, STATUS_OK, 0x00];
    raw.resize(REPORT_SIZE, 0x00);

    let result = parse_response_validated(&raw, None, Some(CMD_GET));
    assert!(result.is_err());
    assert!(matches!(
        result.unwrap_err(),
        CorsairError::UnexpectedResponse { .. }
    ));
}

#[test]
fn parse_response_validated_accepts_matching() {
    let mut raw = vec![0x01, RESPONSE_ENDPOINT_HEADSET, CMD_GET, STATUS_OK, 0xE8, 0x03];
    raw.resize(REPORT_SIZE, 0x00);

    let resp = parse_response_validated(
        &raw,
        Some(RESPONSE_ENDPOINT_HEADSET),
        Some(CMD_GET),
    )
    .unwrap();

    assert_eq!(resp.endpoint, RESPONSE_ENDPOINT_HEADSET);
    assert_eq!(resp.command, CMD_GET);
    assert_eq!(resp.status, STATUS_OK);
}