use hex_pigeon_parser::checksum::{compute_crc16, compute_crc32};
use hex_pigeon_parser::{
    parse_fields, CountSpec, Endian, FieldDef, FieldKind, FlagDef, ParsedValue, Schema,
};

fn field(name: &str, kind: FieldKind) -> FieldDef {
    FieldDef {
        name: name.to_string(),
        kind,
        endian: None,
        description: None,
        flags: None,
        length: None,
        checksum_range: None,
        count: None,
        fields: None,
    }
}

fn field_len(name: &str, kind: FieldKind, length: usize) -> FieldDef {
    let mut f = field(name, kind);
    f.length = Some(length);
    f
}

#[test]
fn schema_deserializes_from_json() {
    let json = r#"{
        "name": "Test",
        "endian": "little",
        "fields": [{ "name": "id", "type": "uint8" }]
    }"#;
    let schema: Schema = serde_json::from_str(json).expect("schema JSON");
    assert_eq!(schema.name.as_deref(), Some("Test"));
    assert_eq!(schema.endian, Endian::Little);
    assert_eq!(schema.fields.len(), 1);
    assert_eq!(schema.fields[0].kind, FieldKind::Uint8);
}

#[test]
fn parses_integer_types_big_endian() {
    let data = [
        0x12,
        0x12, 0x34,
        0x12, 0x34, 0x56, 0x78,
        0x12, 0x34, 0x56, 0x78, 0x9A, 0xBC, 0xDE, 0xF0,
        0xFE,
        0xFF, 0xF0,
        0x80, 0x00, 0x00, 0x01,
    ];
    let fields = vec![
        field("u8", FieldKind::Uint8),
        field("u16", FieldKind::Uint16),
        field("u32", FieldKind::Uint32),
        field("u64", FieldKind::Uint64),
        field("i8", FieldKind::Int8),
        field("i16", FieldKind::Int16),
        field("i32", FieldKind::Int32),
    ];
    let result = parse_fields(&data, &fields).expect("parse");

    assert_eq!(result.consumed_bytes, 22);
    assert!(matches!(result.fields[0].value, ParsedValue::Uint(0x12)));
    assert!(matches!(result.fields[1].value, ParsedValue::Uint(0x1234)));
    assert!(matches!(result.fields[2].value, ParsedValue::Uint(0x12345678)));
    assert!(matches!(result.fields[3].value, ParsedValue::Uint(0x123456789ABCDEF0)));
    assert!(matches!(result.fields[4].value, ParsedValue::Int(-2)));
    assert!(matches!(result.fields[5].value, ParsedValue::Int(-16)));
    assert!(matches!(result.fields[6].value, ParsedValue::Int(-2147483647)));
}

#[test]
fn parses_integer_types_little_endian() {
    let data = [0x34, 0x12];
    let mut f = field("u16", FieldKind::Uint16);
    f.endian = Some(Endian::Little);
    let result = parse_fields(&data, &[f]).expect("parse");
    assert!(matches!(result.fields[0].value, ParsedValue::Uint(0x1234)));
}

#[test]
fn parses_float_types() {
    let f32_bits = 1.0f32.to_bits();
    let f64_bits = 2.5f64.to_bits();
    let mut data = Vec::new();
    data.extend_from_slice(&f32_bits.to_be_bytes());
    data.extend_from_slice(&f64_bits.to_be_bytes());

    let fields = vec![field("f32", FieldKind::Float32), field("f64", FieldKind::Float64)];
    let result = parse_fields(&data, &fields).expect("parse");

    match &result.fields[0].value {
        ParsedValue::Float(v) => assert!((v - 1.0).abs() < f64::EPSILON),
        other => panic!("expected float32, got {other:?}"),
    }
    match &result.fields[1].value {
        ParsedValue::Float(v) => assert!((v - 2.5).abs() < f64::EPSILON),
        other => panic!("expected float64, got {other:?}"),
    }
}

#[test]
fn parses_bitflags() {
    let mut f8 = field("flags8", FieldKind::Bitflags8);
    f8.flags = Some(vec![
        FlagDef {
            bit: 0,
            name: "A".into(),
            description: None,
        },
        FlagDef {
            bit: 3,
            name: "D".into(),
            description: None,
        },
    ]);
    let mut f16 = field("flags16", FieldKind::Bitflags16);
    f16.flags = Some(vec![FlagDef {
        bit: 1,
        name: "B".into(),
        description: None,
    }]);

    let result = parse_fields(&[0b0000_0101, 0x00, 0b0000_0010], &[f8, f16]).expect("parse");

    match &result.fields[0].value {
        ParsedValue::Flags(flags) => {
            assert!(flags.iter().find(|f| f.name == "A").unwrap().set);
            assert!(!flags.iter().find(|f| f.name == "D").unwrap().set);
        }
        other => panic!("expected flags8, got {other:?}"),
    }
    match &result.fields[1].value {
        ParsedValue::Flags(flags) => assert!(flags[0].set),
        other => panic!("expected flags16, got {other:?}"),
    }
}

#[test]
fn parses_bytes_padding_and_strings() {
    let data = [
        0xAA, 0xBB, 0xCC, // bytes[3]
        0x00, 0x00, // padding[2]
        b'H', b'i', 0x00, 0x00, // string_fixed[4] -> "Hi"
        0x03, b'F', b'O', b'O', // string_lp8
        0x00, 0x02, b'B', b'R', // string_lp16 big-endian length
    ];

    let fields = vec![
        field_len("raw", FieldKind::Bytes, 3),
        field_len("pad", FieldKind::Padding, 2),
        field_len("fixed", FieldKind::StringFixed, 4),
        field("lp8", FieldKind::StringLp8),
        field("lp16", FieldKind::StringLp16),
    ];
    let result = parse_fields(&data, &fields).expect("parse");

    assert!(matches!(&result.fields[0].value, ParsedValue::Bytes(v) if v == &[0xAA, 0xBB, 0xCC]));
    assert!(matches!(result.fields[1].value, ParsedValue::None));
    assert!(matches!(&result.fields[2].value, ParsedValue::Str(s) if s == "Hi"));
    assert!(matches!(&result.fields[3].value, ParsedValue::Str(s) if s == "FOO"));
    assert!(matches!(&result.fields[4].value, ParsedValue::Str(s) if s == "BR"));
}

#[test]
fn validates_crc16_and_crc32() {
    let payload = [0x01, 0x02, 0x03, 0x04];
    let crc16 = compute_crc16(&payload);
    let crc32 = compute_crc32(&payload);

    let mut data = payload.to_vec();
    data.extend_from_slice(&crc16.to_be_bytes());
    data.extend_from_slice(&crc32.to_be_bytes());

    let mut crc16_field = field("c16", FieldKind::Crc16);
    crc16_field.checksum_range = Some([0, 4]);
    let mut crc32_field = field("c32", FieldKind::Crc32);
    crc32_field.checksum_range = Some([0, 4]);

    let fields = vec![
        field_len("payload", FieldKind::Bytes, 4),
        crc16_field,
        crc32_field,
    ];
    let result = parse_fields(&data, &fields).expect("parse");
    assert_eq!(result.fields[1].checksum_valid, Some(true));
    assert_eq!(result.fields[2].checksum_valid, Some(true));

    let mut bad = data.clone();
    bad[6] ^= 0xFF;
    let mut crc32_bad = field("c32", FieldKind::Crc32);
    crc32_bad.checksum_range = Some([0, 4]);
    let fields = vec![
        field_len("payload", FieldKind::Bytes, 4),
        crc32_bad,
    ];
    let result = parse_fields(&bad, &fields).expect("parse");
    assert_eq!(result.fields[1].checksum_valid, Some(false));
}

#[test]
fn parses_repeated_fixed_and_dynamic_count() {
    let data = [0x02, 0x10, 0x20, 0x11, 0x21];

    let repeated_fixed = FieldDef {
        name: "items".into(),
        kind: FieldKind::Repeated,
        endian: None,
        description: None,
        flags: None,
        length: None,
        checksum_range: None,
        count: Some(CountSpec::Fixed(2)),
        fields: Some(vec![field("val", FieldKind::Uint8)]),
    };
    let result = parse_fields(&[0x10, 0x20, 0x11, 0x21], &[repeated_fixed]).expect("parse");
    let children = result.fields[0].children.as_ref().expect("children");
    assert_eq!(children.len(), 2);
    assert!(matches!(children[0].value, ParsedValue::Uint(0x10)));
    assert!(matches!(children[1].value, ParsedValue::Uint(0x20)));

    let repeated_dynamic = FieldDef {
        name: "list".into(),
        kind: FieldKind::Repeated,
        endian: None,
        description: None,
        flags: None,
        length: None,
        checksum_range: None,
        count: Some(CountSpec::Field("count".into())),
        fields: Some(vec![field("val", FieldKind::Uint8)]),
    };
    let result = parse_fields(&data, &[field("count", FieldKind::Uint8), repeated_dynamic]).expect("parse");
    let children = result.fields[1].children.as_ref().expect("children");
    assert_eq!(children.len(), 2);
}

#[test]
fn errors_on_truncated_buffer() {
    let result = parse_fields(&[0x01], &[field("u16", FieldKind::Uint16)]);
    assert!(result.is_err());
    assert!(result.unwrap_err().contains("Not enough bytes"));
}

#[test]
fn errors_on_missing_required_field_options() {
    let err = parse_fields(&[0x01], &[field("raw", FieldKind::Bytes)]).unwrap_err();
    assert!(err.contains("requires 'length'"));

    let repeated = FieldDef {
        name: "r".into(),
        kind: FieldKind::Repeated,
        endian: None,
        description: None,
        flags: None,
        length: None,
        checksum_range: None,
        count: Some(CountSpec::Fixed(1)),
        fields: None,
    };
    let err = parse_fields(&[0x01], &[repeated]).unwrap_err();
    assert!(err.contains("requires 'fields'"));
}

#[test]
fn parses_example_protocol_frame() {
    let header = [
        0xFF, 0x05, b'H', b'e', b'l', b'l', b'o', 0x00, 0x01, 0x02, 0x03, b'A', b'B', b'C',
        b'D',
    ];
    let crc32 = compute_crc32(&header[..11]);
    let mut data = header.to_vec();
    data.extend_from_slice(&crc32.to_be_bytes());
    data.extend_from_slice(&[0x00, 0x03]); // flags: ACK + SYN

    let schema_json = include_str!("../../frontend/src/fixtures/example-schema.json");
    let schema: Schema = serde_json::from_str(schema_json).expect("example schema");
    let result = parse_fields(&data, &schema.fields).expect("example frame");

    assert_eq!(result.total_bytes, data.len());
    assert_eq!(result.consumed_bytes, data.len());
    assert_eq!(result.fields.len(), 7);

    assert!(matches!(result.fields[0].value, ParsedValue::Uint(0xFF)));
    assert!(matches!(&result.fields[2].value, ParsedValue::Str(s) if s == "Hello"));
    assert!(matches!(&result.fields[4].value, ParsedValue::Str(s) if s == "ABCD"));
    assert_eq!(result.fields[5].checksum_valid, Some(true));

    match &result.fields[6].value {
        ParsedValue::Flags(flags) => {
            assert!(flags.iter().find(|f| f.name == "ACK").unwrap().set);
            assert!(flags.iter().find(|f| f.name == "SYN").unwrap().set);
            assert!(!flags.iter().find(|f| f.name == "FIN").unwrap().set);
        }
        other => panic!("expected flags, got {other:?}"),
    }
}