servicepoint-binding-uniffi/src/command.rs

use std::io::Read;
use flate2::bufread::GzEncoder;
use flate2::Compression;
use flate2::read::GzDecoder;
use crate::{BitVec, ByteGrid, Header, Packet, PixelGrid, TILE_SIZE};
use crate::command_codes::{CommandCode, CompressionCode};

/// An origin marks the top left position of the
/// data sent to the display.
#[derive(Debug, Clone, Copy)]
pub struct Origin(pub u16, pub u16);

impl Origin {
    pub fn top_left() -> Self {
        Self(0, 0)
    }
}

/// Size defines the width and height of a window
#[derive(Debug, Clone, Copy)]
pub struct Size(pub u16, pub u16);

type Offset = u16;

type Brightness = u8;

#[derive(Debug)]
pub enum Command {
    Clear,
    HardReset,
    FadeOut,
    CharBrightness(Origin, ByteGrid),
    Brightness(Brightness),
    #[deprecated]
    BitmapLegacy,
    BitmapLinear(Offset, BitVec, CompressionCode),
    BitmapLinearAnd(Offset, BitVec, CompressionCode),
    BitmapLinearOr(Offset, BitVec, CompressionCode),
    BitmapLinearXor(Offset, BitVec, CompressionCode),
    Cp437Data(Origin, ByteGrid),
    BitmapLinearWin(Origin, PixelGrid),
}

impl Into<Packet> for Command {
    fn into(self) -> Packet {
        match self {
            Command::Clear => command_code_only(CommandCode::Clear),
            Command::FadeOut => command_code_only(CommandCode::FadeOut),
            Command::HardReset => command_code_only(CommandCode::HardReset),
            #[allow(deprecated)]
            Command::BitmapLegacy => command_code_only(CommandCode::BitmapLegacy),
            Command::CharBrightness(origin, grid) => {
                origin_size_payload(CommandCode::CharBrightness,
                                    origin,
                                    Size(grid.width as u16, grid.height as u16),
                                    grid.into())
            }
            Command::Brightness(brightness) => {
                Packet(Header(CommandCode::Brightness.to_primitive(), 0x00000, 0x0000, 0x0000, 0x0000), vec!(brightness))
            }
            Command::BitmapLinearWin(Origin(pixel_x, pixel_y), pixels) => {
                debug_assert_eq!(pixel_x % 8, 0);
                debug_assert_eq!(pixels.width % 8, 0);
                Packet(
                    Header(CommandCode::BitmapLinearWin.to_primitive(),
                           pixel_x / TILE_SIZE,
                           pixel_y,
                           pixels.width as u16 / TILE_SIZE,
                           pixels.height as u16),
                    pixels.into())
            }
            Command::BitmapLinear(offset, bits, compression) => {
                bitmap_linear_into_packet(CommandCode::BitmapLinear, offset, compression, bits.into())
            }
            Command::BitmapLinearAnd(offset, bits, compression) => {
                bitmap_linear_into_packet(CommandCode::BitmapLinearAnd, offset, compression, bits.into())
            }
            Command::BitmapLinearOr(offset, bits, compression) => {
                bitmap_linear_into_packet(CommandCode::BitmapLinearOr, offset, compression, bits.into())
            }
            Command::BitmapLinearXor(offset, bits, compression) => {
                bitmap_linear_into_packet(CommandCode::BitmapLinearXor, offset, compression, bits.into())
            }
            Command::Cp437Data(origin, grid) => {
                origin_size_payload(CommandCode::Cp437Data,
                                    origin,
                                    Size(grid.width as u16, grid.height as u16),
                                    grid.into())
            }
        }
    }
}

#[derive(Debug)]
pub enum TryFromPacketError {
    InvalidCommand(u16),
    UnexpectedPayloadSize(usize, usize),
    ExtraneousHeaderValues,
    InvalidCompressionCode(u16),
    DecompressionFailed(std::io::Error),
}

impl TryFrom<Packet> for Command {
    type Error = TryFromPacketError;

    fn try_from(value: Packet) -> Result<Self, Self::Error> {
        let Packet(Header(command_u16, a, b, c, d), _) = value;
        let command_code = match CommandCode::from_primitive(command_u16) {
            None => return Err(TryFromPacketError::InvalidCommand(command_u16)),
            Some(value) => value
        };

        match command_code {
            CommandCode::Clear => {
                match check_command_only(value) {
                    Some(err) => Err(err),
                    None => Ok(Command::Clear),
                }
            }
            CommandCode::Brightness => {
                let Packet(header, payload) = value;
                if payload.len() != 1 {
                    return Err(TryFromPacketError::UnexpectedPayloadSize(1, payload.len()));
                }

                match check_empty_header(header) {
                    Some(err) => Err(err),
                    None => Ok(Command::Brightness(payload[0])),
                }
            }
            CommandCode::HardReset => {
                match check_command_only(value) {
                    Some(err) => Err(err),
                    None => Ok(Command::HardReset),
                }
            }
            CommandCode::FadeOut => {
                match check_command_only(value) {
                    Some(err) => Err(err),
                    None => Ok(Command::FadeOut),
                }
            }
            CommandCode::Cp437Data => {
                let Packet(_, payload) = value;
                Ok(Command::Cp437Data(
                    Origin(a, b),
                    ByteGrid::load(c as usize, d as usize, &payload),
                ))
            }
            CommandCode::CharBrightness => {
                let Packet(_, payload) = value;
                Ok(Command::CharBrightness(
                    Origin(a, b),
                    ByteGrid::load(c as usize, d as usize, &payload),
                ))
            }
            #[allow(deprecated)]
            CommandCode::BitmapLegacy => {
                Ok(Command::BitmapLegacy)
            }
            CommandCode::BitmapLinearWin => {
                let Packet(_, payload) = value;
                Ok(Command::BitmapLinearWin(
                    Origin(a * TILE_SIZE, b),
                    PixelGrid::load(c as usize * TILE_SIZE as usize, d as usize, &payload),
                ))
            }
            CommandCode::BitmapLinear => {
                let (vec, compression) = packet_into_linear_bitmap(value)?;
                Ok(Command::BitmapLinear(a, vec, compression))
            }
            CommandCode::BitmapLinearAnd => {
                let (vec, compression) = packet_into_linear_bitmap(value)?;
                Ok(Command::BitmapLinearAnd(a, vec, compression))
            }
            CommandCode::BitmapLinearOr => {
                let (vec, compression) = packet_into_linear_bitmap(value)?;
                Ok(Command::BitmapLinearOr(a, vec, compression))
            }
            CommandCode::BitmapLinearXor => {
                let (vec, compression) = packet_into_linear_bitmap(value)?;
                Ok(Command::BitmapLinearXor(a, vec, compression))
            }
        }
    }
}

fn bitmap_linear_into_packet(command: CommandCode, offset: Offset, compression: CompressionCode, payload: Vec<u8>) -> Packet {
    let payload = match compression {
        CompressionCode::None => payload,
        CompressionCode::Gz => {
            let mut encoder = GzEncoder::new(&*payload, Compression::best());
            let mut compressed = vec!();
            match encoder.read_to_end(&mut compressed) {
                Err(err) => panic!("could not compress payload: {}", err),
                Ok(_) => compressed,
            }
        }
        CompressionCode::Bz => todo!(),
        CompressionCode::Lz => todo!(),
        CompressionCode::Zs => todo!(),
    };

    let compression = CompressionCode::to_primitive(&compression);
    Packet(Header(command.to_primitive(), offset, payload.len() as u16, compression, 0), payload)
}

fn origin_size_payload(command: CommandCode, origin: Origin, size: Size, payload: Vec<u8>) -> Packet {
    let Origin(x, y) = origin;
    let Size(w, h) = size;
    Packet(Header(command.to_primitive(), x, y, w, h), payload.into())
}

fn command_code_only(code: CommandCode) -> Packet {
    Packet(Header(code.to_primitive(), 0x0000, 0x0000, 0x0000, 0x0000), vec!())
}

fn check_empty_header(header: Header) -> Option<TryFromPacketError> {
    let Header(_, a, b, c, d) = header;
    if a != 0 || b != 0 || c != 0 || d != 0 {
        Some(TryFromPacketError::ExtraneousHeaderValues)
    } else {
        None
    }
}

fn check_command_only(packet: Packet) -> Option<TryFromPacketError> {
    let Packet(Header(_, a, b, c, d), payload) = packet;
    if payload.len() != 0 {
        Some(TryFromPacketError::UnexpectedPayloadSize(0, payload.len()))
    } else if a != 0 || b != 0 || c != 0 || d != 0 {
        Some(TryFromPacketError::ExtraneousHeaderValues)
    } else {
        None
    }
}

fn packet_into_linear_bitmap(packet: Packet) -> Result<(BitVec, CompressionCode), TryFromPacketError> {
    let Packet(Header(_, _, length, sub, reserved), payload) = packet;
    if reserved != 0 {
        return Err(TryFromPacketError::ExtraneousHeaderValues);
    }
    if payload.len() != length as usize {
        return Err(TryFromPacketError::UnexpectedPayloadSize(length as usize, payload.len()));
    }
    let sub = match CompressionCode::from_primitive(sub) {
        None => return Err(TryFromPacketError::InvalidCompressionCode(sub)),
        Some(value) => value
    };
    let payload = match sub {
        CompressionCode::None => payload,
        CompressionCode::Gz => {
            let mut decoder = GzDecoder::new(&*payload);
            let mut decompressed = vec!();
            match decoder.read_to_end(&mut decompressed) {
                Err(err) => return Err(TryFromPacketError::DecompressionFailed(err)),
                Ok(_) => {}
            }
            decompressed
        }
        CompressionCode::Bz => todo!(),
        CompressionCode::Lz => todo!(),
        CompressionCode::Zs => todo!(),
    };

    Ok((BitVec::load(&payload), sub))
}