ftui-extras 0.3.1

//! Raw binary structures from the WAD file format.
//!
//! All structures are parsed from little-endian binary data matching
//! the original Doom WAD specification.

/// WAD file header (12 bytes).
#[derive(Debug, Clone)]
pub struct WadHeader {
    /// "IWAD" or "PWAD"
    pub identification: [u8; 4],
    /// Number of lumps in the directory.
    pub num_lumps: i32,
    /// Offset to the directory table.
    pub info_table_ofs: i32,
}

/// Directory entry (16 bytes).
#[derive(Debug, Clone)]
pub struct DirEntry {
    /// Offset to the lump data in the file.
    pub filepos: i32,
    /// Size of the lump in bytes.
    pub size: i32,
    /// 8-character ASCII name (null-padded).
    pub name: [u8; 8],
}

impl DirEntry {
    /// Get the name as a trimmed uppercase string.
    pub fn name_str(&self) -> String {
        let end = self.name.iter().position(|&b| b == 0).unwrap_or(8);
        String::from_utf8_lossy(&self.name[..end]).to_uppercase()
    }
}

/// Vertex (4 bytes): x, y as i16 in map units.
#[derive(Debug, Clone, Copy)]
pub struct RawVertex {
    pub x: i16,
    pub y: i16,
}

/// LineDef (14 bytes): wall segment between two vertices.
#[derive(Debug, Clone, Copy)]
pub struct RawLineDef {
    pub v1: u16,
    pub v2: u16,
    pub flags: u16,
    pub special: u16,
    pub tag: u16,
    pub right_sidedef: u16,
    pub left_sidedef: u16,
}

/// LineDef flags.
pub const ML_BLOCKING: u16 = 1;
pub const ML_TWOSIDED: u16 = 4;
pub const ML_DONTPEGTOP: u16 = 8;
pub const ML_DONTPEGBOTTOM: u16 = 16;
pub const ML_SECRET: u16 = 32;
pub const ML_SOUNDBLOCK: u16 = 64;
pub const ML_DONTDRAW: u16 = 128;
pub const ML_MAPPED: u16 = 256;

/// SideDef (30 bytes): texture info for one side of a linedef.
#[derive(Debug, Clone)]
pub struct RawSideDef {
    pub x_offset: i16,
    pub y_offset: i16,
    pub upper_texture: [u8; 8],
    pub lower_texture: [u8; 8],
    pub middle_texture: [u8; 8],
    pub sector: u16,
}

impl RawSideDef {
    pub fn upper_name(&self) -> String {
        lump_name_str(&self.upper_texture)
    }
    pub fn lower_name(&self) -> String {
        lump_name_str(&self.lower_texture)
    }
    pub fn middle_name(&self) -> String {
        lump_name_str(&self.middle_texture)
    }
}

/// Sector (26 bytes): floor/ceiling info.
#[derive(Debug, Clone)]
pub struct RawSector {
    pub floor_height: i16,
    pub ceiling_height: i16,
    pub floor_texture: [u8; 8],
    pub ceiling_texture: [u8; 8],
    pub light_level: u16,
    pub special: u16,
    pub tag: u16,
}

impl RawSector {
    pub fn floor_name(&self) -> String {
        lump_name_str(&self.floor_texture)
    }
    pub fn ceiling_name(&self) -> String {
        lump_name_str(&self.ceiling_texture)
    }
}

/// Seg (12 bytes): sub-segment of a linedef.
#[derive(Debug, Clone, Copy)]
pub struct RawSeg {
    pub v1: u16,
    pub v2: u16,
    pub angle: i16,
    pub linedef: u16,
    pub direction: u16,
    pub offset: i16,
}

/// SubSector (4 bytes): convex region of the map.
#[derive(Debug, Clone, Copy)]
pub struct RawSubSector {
    pub num_segs: u16,
    pub first_seg: u16,
}

/// BSP Node (28 bytes).
#[derive(Debug, Clone, Copy)]
pub struct RawNode {
    /// Partition line start x.
    pub x: i16,
    /// Partition line start y.
    pub y: i16,
    /// Partition line direction x.
    pub dx: i16,
    /// Partition line direction y.
    pub dy: i16,
    /// Bounding box for right child [top, bottom, left, right].
    pub bbox_right: [i16; 4],
    /// Bounding box for left child [top, bottom, left, right].
    pub bbox_left: [i16; 4],
    /// Right child (high bit set = subsector).
    pub right_child: u16,
    /// Left child (high bit set = subsector).
    pub left_child: u16,
}

/// Bit flag indicating a node child is a subsector.
pub const NF_SUBSECTOR: u16 = 0x8000;

/// Thing (10 bytes): map object placement.
#[derive(Debug, Clone, Copy)]
pub struct RawThing {
    pub x: i16,
    pub y: i16,
    pub angle: u16,
    pub thing_type: u16,
    pub flags: u16,
}

/// Thing flag: appears on skill 1-2.
pub const MTF_EASY: u16 = 1;
/// Thing flag: appears on skill 3.
pub const MTF_NORMAL: u16 = 2;
/// Thing flag: appears on skill 4-5.
pub const MTF_HARD: u16 = 4;
/// Thing flag: deaf (ambush).
pub const MTF_AMBUSH: u16 = 8;
/// Thing flag: multiplayer only.
pub const MTF_MULTI: u16 = 16;

/// Player 1 start thing type.
pub const THING_PLAYER1: u16 = 1;

/// Helper: convert an 8-byte lump name to a trimmed uppercase string.
pub fn lump_name_str(name: &[u8; 8]) -> String {
    let end = name.iter().position(|&b| b == 0).unwrap_or(8);
    String::from_utf8_lossy(&name[..end]).to_uppercase()
}

/// Parse helpers: read little-endian integers from a byte slice.
pub mod parse {
    #[inline]
    pub fn i16_le(data: &[u8], offset: usize) -> i16 {
        i16::from_le_bytes([data[offset], data[offset + 1]])
    }

    #[inline]
    pub fn u16_le(data: &[u8], offset: usize) -> u16 {
        u16::from_le_bytes([data[offset], data[offset + 1]])
    }

    #[inline]
    pub fn i32_le(data: &[u8], offset: usize) -> i32 {
        i32::from_le_bytes([
            data[offset],
            data[offset + 1],
            data[offset + 2],
            data[offset + 3],
        ])
    }

    /// Read an 8-byte fixed-length name field.
    #[inline]
    pub fn name8(data: &[u8], offset: usize) -> [u8; 8] {
        let mut buf = [0u8; 8];
        buf.copy_from_slice(&data[offset..offset + 8]);
        buf
    }
}

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

    // --- lump_name_str ---

    #[test]
    fn lump_name_str_full_name() {
        let name = [b'E', b'1', b'M', b'1', 0, 0, 0, 0];
        assert_eq!(lump_name_str(&name), "E1M1");
    }

    #[test]
    fn lump_name_str_full_8_chars() {
        let name = [b'L', b'I', b'N', b'E', b'D', b'E', b'F', b'S'];
        assert_eq!(lump_name_str(&name), "LINEDEFS");
    }

    #[test]
    fn lump_name_str_all_zeroes() {
        let name = [0u8; 8];
        assert_eq!(lump_name_str(&name), "");
    }

    #[test]
    fn lump_name_str_lowercase_uppercased() {
        let name = [b'f', b'l', b'a', b't', 0, 0, 0, 0];
        assert_eq!(lump_name_str(&name), "FLAT");
    }

    // --- DirEntry::name_str ---

    #[test]
    fn dir_entry_name_str() {
        let entry = DirEntry {
            filepos: 0,
            size: 100,
            name: [b'T', b'H', b'I', b'N', b'G', b'S', 0, 0],
        };
        assert_eq!(entry.name_str(), "THINGS");
    }

    // --- RawSideDef texture names ---

    #[test]
    fn sidedef_texture_names() {
        let sd = RawSideDef {
            x_offset: 0,
            y_offset: 0,
            upper_texture: [b'S', b'K', b'Y', b'1', 0, 0, 0, 0],
            lower_texture: [b'-', 0, 0, 0, 0, 0, 0, 0],
            middle_texture: [b'D', b'O', b'O', b'R', b'1', 0, 0, 0],
            sector: 0,
        };
        assert_eq!(sd.upper_name(), "SKY1");
        assert_eq!(sd.lower_name(), "-");
        assert_eq!(sd.middle_name(), "DOOR1");
    }

    // --- RawSector texture names ---

    #[test]
    fn sector_texture_names() {
        let sector = RawSector {
            floor_height: 0,
            ceiling_height: 128,
            floor_texture: [b'F', b'L', b'A', b'T', b'1', 0, 0, 0],
            ceiling_texture: [b'C', b'E', b'I', b'L', b'3', 0, 0, 0],
            light_level: 160,
            special: 0,
            tag: 0,
        };
        assert_eq!(sector.floor_name(), "FLAT1");
        assert_eq!(sector.ceiling_name(), "CEIL3");
    }

    // --- parse helpers ---

    #[test]
    fn parse_i16_le_positive() {
        let data = [0x34, 0x12]; // 0x1234 = 4660
        assert_eq!(parse::i16_le(&data, 0), 0x1234);
    }

    #[test]
    fn parse_i16_le_negative() {
        let data = [0xFF, 0xFF]; // -1
        assert_eq!(parse::i16_le(&data, 0), -1);
    }

    #[test]
    fn parse_i16_le_with_offset() {
        let data = [0xAA, 0xBB, 0x34, 0x12];
        assert_eq!(parse::i16_le(&data, 2), 0x1234);
    }

    #[test]
    fn parse_u16_le() {
        let data = [0xFF, 0xFF]; // 65535
        assert_eq!(parse::u16_le(&data, 0), 0xFFFF);
    }

    #[test]
    fn parse_i32_le() {
        let data = [0x78, 0x56, 0x34, 0x12]; // 0x12345678
        assert_eq!(parse::i32_le(&data, 0), 0x12345678);
    }

    #[test]
    fn parse_i32_le_negative() {
        let data = [0xFF, 0xFF, 0xFF, 0xFF]; // -1
        assert_eq!(parse::i32_le(&data, 0), -1);
    }

    #[test]
    fn parse_name8() {
        let data = [0, 0, b'T', b'E', b'S', b'T', 0, 0, 0, 0];
        let name = parse::name8(&data, 2);
        assert_eq!(&name, b"TEST\0\0\0\0");
    }

    // --- LineDef flags ---

    #[test]
    fn linedef_flag_values() {
        assert_eq!(ML_BLOCKING, 1);
        assert_eq!(ML_TWOSIDED, 4);
        assert_eq!(ML_DONTPEGTOP, 8);
        assert_eq!(ML_DONTPEGBOTTOM, 16);
        assert_eq!(ML_SECRET, 32);
        assert_eq!(ML_SOUNDBLOCK, 64);
        assert_eq!(ML_DONTDRAW, 128);
        assert_eq!(ML_MAPPED, 256);
    }

    // --- Thing flags ---

    #[test]
    fn thing_flag_values() {
        assert_eq!(MTF_EASY, 1);
        assert_eq!(MTF_NORMAL, 2);
        assert_eq!(MTF_HARD, 4);
        assert_eq!(MTF_AMBUSH, 8);
        assert_eq!(MTF_MULTI, 16);
    }

    #[test]
    fn nf_subsector_flag() {
        assert_eq!(NF_SUBSECTOR, 0x8000);
    }

    #[test]
    fn thing_player1_type() {
        assert_eq!(THING_PLAYER1, 1);
    }
}