cat-dev 0.0.13

//! The server implementation for handling ATAPI Emulation.

use crate::{
	errors::{APIError, CatBridgeError, FSError},
	fsemul::{HostFilesystem, dlf::DiskLayoutFile},
	net::{
		DEFAULT_CAT_DEV_CHUNK_SIZE, DEFAULT_CAT_DEV_SLOWDOWN,
		additions::{RequestIDLayer, StreamIDLayer},
		server::{
			Router, TCPServer,
			requestable::{Body, State},
		},
	},
};
use bytes::{BufMut, Bytes, BytesMut};
use local_ip_address::local_ip;
use std::{
	net::{IpAddr, Ipv4Addr, SocketAddrV4},
	time::Duration,
};
use tokio::{
	fs::{File, read as fs_read},
	io::{AsyncReadExt, AsyncSeekExt, SeekFrom},
};
use tower::ServiceBuilder;
use tracing::debug;
use valuable::{Fields, NamedField, NamedValues, StructDef, Structable, Valuable, Value, Visit};

/// The default port to use for hosting the ATAPI Server.
pub const DEFAULT_ATAPI_PORT: u16 = 7974_u16;

/// A builder that is capable of building a brand new ATAPI server.
///
/// This is a small wrapper that tries to make setting the (many) amount of
/// options easier. The shortest version you can do is call
/// [`AtapiServerBuilder::new`], and [`AtapiServerBuilder::build`].
#[derive(Clone, Debug)]
pub struct AtapiServerBuilder {
	/// The explicit bind address if we don't want to use the local address.
	address: Option<Ipv4Addr>,
	/// Allow overriding the amount of time that we wait to make sure everything
	/// is safe for a cat-dev.
	///
	/// *note: `None` does not mean cat-dev sleep is disabled, that is controleld
	/// through [`Self::fully_disable_cat_dev_sleep`]*.
	cat_dev_sleep_override: Option<Duration>,
	/// Override the chunking value, and how many bytes we'll purposefully chunk on
	/// when sending out TCP data.
	///
	/// *note: `None` does not mean cat-dev sleep is disabled, that is controleld
	/// through [`Self::fully_disable_chunk_override`]*.
	chunk_override: Option<usize>,
	/// An override to fully disable any cat-dev sleeping to prevent issues.
	fully_disable_cat_dev_sleep: bool,
	/// An override to fully disable any TCP level chunking.
	fully_disable_chunk_override: bool,
	/// The host filesystem to treat when serving ATAPI requests.
	host_filesystem: HostFilesystem,
	/// The explicit port to bind on, when not using default.
	port: Option<u16>,
	/// If we should trace when in debug mode.
	trace_during_debug: bool,
}

impl AtapiServerBuilder {
	/// Create a new ATAPI Server builder.
	#[must_use]
	pub const fn new(host_filesystem: HostFilesystem) -> Self {
		Self {
			address: None,
			cat_dev_sleep_override: None,
			chunk_override: None,
			fully_disable_cat_dev_sleep: false,
			fully_disable_chunk_override: false,
			host_filesystem,
			port: None,
			trace_during_debug: false,
		}
	}

	#[must_use]
	pub const fn address(&self) -> Option<Ipv4Addr> {
		self.address
	}
	#[must_use]
	pub const fn set_address(mut self, new_address: Option<Ipv4Addr>) -> Self {
		self.address = new_address;
		self
	}

	#[must_use]
	pub const fn cat_dev_sleep_override(&self) -> Option<Duration> {
		self.cat_dev_sleep_override
	}
	#[must_use]
	pub const fn set_cat_dev_sleep_override(mut self, new_override: Option<Duration>) -> Self {
		self.cat_dev_sleep_override = new_override;
		self
	}

	#[must_use]
	pub const fn chunk_override(&self) -> Option<usize> {
		self.chunk_override
	}
	#[must_use]
	pub const fn set_chunk_override(mut self, new_override: Option<usize>) -> Self {
		self.chunk_override = new_override;
		self
	}

	#[must_use]
	pub const fn fully_disable_cat_dev_sleep(&self) -> bool {
		self.fully_disable_cat_dev_sleep
	}
	#[must_use]
	pub const fn set_fully_disable_cat_dev_sleep(mut self, new_value: bool) -> Self {
		self.fully_disable_cat_dev_sleep = new_value;
		self
	}

	#[must_use]
	pub const fn fully_disable_chunking(&self) -> bool {
		self.fully_disable_chunk_override
	}
	#[must_use]
	pub const fn set_fully_disable_chunking(mut self, disable_chunk: bool) -> Self {
		self.fully_disable_chunk_override = disable_chunk;
		self
	}

	#[must_use]
	pub const fn host_filesystem(&self) -> &HostFilesystem {
		&self.host_filesystem
	}
	#[must_use]
	pub fn set_host_filesystem(mut self, new: HostFilesystem) -> Self {
		self.host_filesystem = new;
		self
	}

	#[must_use]
	pub const fn port(&self) -> Option<u16> {
		self.port
	}
	#[must_use]
	pub const fn set_port(mut self, new: Option<u16>) -> Self {
		self.port = new;
		self
	}

	#[must_use]
	pub const fn trace_during_debug(&self) -> bool {
		self.trace_during_debug
	}
	#[must_use]
	pub const fn set_trace_during_debug(mut self, trace: bool) -> Self {
		self.trace_during_debug = trace;
		self
	}

	/// Build this server, and get a TCP server that you can bind and use.
	///
	/// ## Errors
	///
	/// If we cannot find a host ip to bind too, or cannot spin up the workers for
	/// the server.
	pub async fn build(self) -> Result<TCPServer<HostFilesystem>, CatBridgeError> {
		let ip = self
			.address
			.or_else(|| {
				local_ip().ok().map(|ip| match ip {
					IpAddr::V4(v4) => v4,
					IpAddr::V6(_v6) => unreachable!(),
				})
			})
			.ok_or(APIError::NoHostIpFound)?;
		let bound_address = SocketAddrV4::new(ip, self.port.unwrap_or(DEFAULT_ATAPI_PORT));

		let mut router = Router::<HostFilesystem>::new();
		router.fallback_handler(temporary_fallback_handle_all)?;

		let mut server = TCPServer::new_with_state(
			"atapi",
			bound_address,
			router,
			(None, None),
			12,
			self.host_filesystem,
			self.trace_during_debug,
		)
		.await?;
		if self.trace_during_debug {
			server.layer_initial_service(
				ServiceBuilder::new()
					.layer(RequestIDLayer::new("atapi".to_owned()))
					.layer(StreamIDLayer),
			);
		} else {
			server.layer_initial_service(
				ServiceBuilder::new().layer(RequestIDLayer::new("atapi".to_owned())),
			);
		}
		server.set_chunk_output_at_size(if self.fully_disable_chunk_override {
			None
		} else if let Some(over_ride) = self.chunk_override {
			Some(over_ride)
		} else {
			Some(DEFAULT_CAT_DEV_CHUNK_SIZE)
		});
		server.set_cat_dev_slowdown(if self.fully_disable_cat_dev_sleep {
			None
		} else if let Some(over_ride) = self.cat_dev_sleep_override {
			Some(over_ride)
		} else {
			Some(DEFAULT_CAT_DEV_SLOWDOWN)
		});

		Ok(server)
	}
}

const ATAPI_SERVER_BUILDER_FIELDS: &[NamedField<'static>] = &[
	NamedField::new("address"),
	NamedField::new("cat_dev_sleep_override"),
	NamedField::new("chunk_override"),
	NamedField::new("fully_disable_cat_dev_sleep"),
	NamedField::new("fully_disable_chunk_override"),
	NamedField::new("host_filesystem"),
	NamedField::new("port"),
	NamedField::new("trace_during_debug"),
];

impl Structable for AtapiServerBuilder {
	fn definition(&self) -> StructDef<'_> {
		StructDef::new_static(
			"AtapiServerBuilder",
			Fields::Named(ATAPI_SERVER_BUILDER_FIELDS),
		)
	}
}

impl Valuable for AtapiServerBuilder {
	fn as_value(&self) -> Value<'_> {
		Value::Structable(self)
	}

	fn visit(&self, visitor: &mut dyn Visit) {
		visitor.visit_named_fields(&NamedValues::new(
			ATAPI_SERVER_BUILDER_FIELDS,
			&[
				Valuable::as_value(
					&self
						.address
						.map_or_else(|| "<none>".to_owned(), |ip| format!("{ip}")),
				),
				Valuable::as_value(
					&self
						.cat_dev_sleep_override
						.map_or_else(|| "<none>".to_owned(), |dur| format!("{}s", dur.as_secs())),
				),
				Valuable::as_value(&self.chunk_override),
				Valuable::as_value(&self.fully_disable_cat_dev_sleep),
				Valuable::as_value(&self.fully_disable_chunk_override),
				Valuable::as_value(&self.host_filesystem),
				Valuable::as_value(&self.port),
				Valuable::as_value(&self.trace_during_debug),
			],
		));
	}
}

async fn temporary_fallback_handle_all(
	State(fs): State<HostFilesystem>,
	Body(packet): Body<Bytes>,
) -> Result<Option<Bytes>, CatBridgeError> {
	match &packet[..2] {
		[0x3, _] => {
			debug!("Would have sent 32 bytes of various descriptions back... not sure which...");
		}
		[0xCF, 0x80] => {
			debug!("ATAPI Event packet sent");
		}
		[0xF0, _] => {
			return Ok(Some(Bytes::from(vec![0x0; 4])));
		}
		[0xF1, 0x00 | 0x02] => {
			// I think this is just random data?
			return Ok(Some(Bytes::from(vec![0x69; 32])));
		}
		[0xF1, 0x01 | 0x03] => {
			debug!("Unknown 0xF1 packet, doesn't do anything on the network...");
		}
		[0xF2, _] => {
			debug!("Got unknown 0xF2 packet: [{packet:02X?}]");
		}
		[0xF3, 0x00] => {
			return handle_read_dlf(packet, &fs).await;
		}
		[0xF3, 0x01] => {
			let mut data = BytesMut::with_capacity(32);
			data.extend_from_slice(b"PC SATA EMUL");
			data.extend_from_slice(&[0_u8; 20]);
			return Ok(Some(data.freeze()));
		}
		[0xF3, 0x02 | 0x03] | [0xF5 | 0xF7, _] => {
			debug!("Sending empty 32 bytes!");
			return Ok(Some(Bytes::from(vec![0x0; 32])));
		}
		[0xF6, _] => {
			if packet[1] & 3 != 0 {
				debug!("F6 second byte & 3 != 0, not sending reply!");
			} else {
				let mut data = BytesMut::with_capacity(4);
				data.put_u32_le(1);
				debug!("Sent F6 reply!");
				return Ok(Some(data.freeze()));
			}
		}
		[0x12, _] => {
			debug!("Would have sent 96 bytes of various descriptions back... not sure which...");
		}
		_ => {}
	}

	Ok(None)
}

async fn handle_read_dlf(
	packet: Bytes,
	host_filesystem: &HostFilesystem,
) -> Result<Option<Bytes>, CatBridgeError> {
	let read_address = u128::from(u32::from_be_bytes([
		packet[0x4],
		packet[0x5],
		packet[0x6],
		packet[0x7],
	])) << 11_u128;
	let read_length = u128::from(u32::from_be_bytes([
		packet[0x8],
		packet[0x9],
		packet[0xA],
		packet[0xB],
	])) << 11_u128;
	let rl_as_usize =
		usize::try_from(read_length).map_err(|_| CatBridgeError::UnsupportedBitsPerCore)?;

	debug!(
		atapi.packet_type = "read_address",
		atapi.read_address.address = %read_address,
		atapi.read_address.length = %read_length,
		"Handling atapi read request!"
	);

	let bytes_of_dlf = fs_read(host_filesystem.ppc_boot_dlf_path().await?)
		.await
		.map_err(FSError::from)?;
	let dlf = DiskLayoutFile::try_from(Bytes::from(bytes_of_dlf))?;

	if let Some((path, offset)) = dlf.get_path_and_offset_for_file(read_address).await {
		// Read the file contents...
		let buff = {
			let mut handle = File::open(&path).await.map_err(FSError::from)?;
			handle
				.seek(SeekFrom::Start(offset))
				.await
				.map_err(FSError::from)?;

			let mut file_buff = BytesMut::zeroed(rl_as_usize);
			let mut bytes_read = 0;
			while bytes_read < rl_as_usize {
				let read_this_go = handle
					.read(&mut file_buff[bytes_read..])
					.await
					.map_err(FSError::IO)?;
				// EOF, rest of the buff is already 0's, so no need to pad.
				if read_this_go == 0 {
					break;
				}
				bytes_read += read_this_go;
			}

			file_buff
		};

		// Send!
		Ok(Some(buff.freeze()))
	} else {
		Ok(Some(BytesMut::zeroed(rl_as_usize).freeze()))
	}
}

// KNOWN PACKET HEADERS
//
//  - [0x3]
//    - send 32 bytes of various describes, not quite sure
//  - [0x12]
//    - sends 96 bytes, seems to have some random spattering of fields
//  - [0xCF, 0x80] -> Triggers Events in FSEmul, probably just call "EVentTrigger"
//  - [0xF0] -> send back 4, 0x0 bytes
//  - [0xF1]
//    - [0xF1, 0x00]
//      - seems to literally send 32 bytes of random data.... cool
//    - [0xF1, 0x02]
//      - seems to literally send 32 bytes of random data.... cool
//    - [0xF1, 0x01] || [0xF1, 0x03]
//      - seems to do nothing on hthe network
//  - [0xF2]
//    - [0xF2, 0x00]
//    - [0xF2, 0x01]
//    - [0xF2, 0x02]
//    - [0xF2, 0x03]
//      -> ??? calls a dynamically allocated thing
//    - [0xF2, 0x06]
//    - [0xF2, 0x07]
//      -> ??? calls a dynamically allocated thing
//      -> for f207 looks like we don't send _anything_ back by default
//      -> seems some paths check for Dvdroot, so maybe dvd stuff?
//  - [0xF3]
//    - [0xF3, 0x0] -> seems to actually be real "read file"
//      - not quite sure exactly how to parse this yet, but these are examples:
//        - first 4 bytes are "packet id"
//        - second 4 bytes are "read address" (calculate by: cast to u128 `<< 11`)
//        - last 4 bytes are "read length" (calculate by: cast to u128 `<< 11`)
//      - logs seem to indicate we:
//         1. read a dlf file (dlf file is populated in cafe-tmp how get?)
//         2. use that to get a max read address
//         3. read from the file
//         4. then pad
//        see logs below:
//          - `CSataProcessor::could not get lead out from dlffileobj {error code}`
//          - `CSataProcessor::requested read address 0x%I64x is out of bounds.`
//          - `CSataProcessor::could not read from file`
//          - `CSataProcessor::padding`
//          - `CSataProcessor::error writing to MION port`
//          - `CSataProcessor::wrote %d bytes`
//    - [0xF3, 0x1] -> send back "PC SATA EMUL" + 20 0's
//    - [0xF3, 0x2] || [0xF3, 0x3] -> send back 32 0's - seems this is always set to 0. maybe a kind of ping?
//  - [0xF5]
//    - send 32 0's
//  - [0xF6]
//    - second byte &3 != 0 -> doesn't send reply
//    - if not send what looks to be `1` encoded as 4 bytes
//  - [0xF7]
//    - send 32 0's