//! Three real separated virtio sectors, bounded logical bytes, and hash oracle.

use super::*;
use os_turkfs_reader::{BlockReader, Error, Extent, File};

const EXPECTED_SHA256: &[u8; 64] =
    b"5ab4d3c0b1612817d6c4335036f9445aead46ff52ff5ae3a00d4245b98582854";

struct Transport<'a>(&'a mut virtio_ro_turkfs::RoDisk);

impl BlockReader for Transport<'_> {
    fn read_block(&mut self, lba: u64, output: &mut [u8; 512]) -> Result<(), ()> {
        self.0.read(lba, output).map_err(|_| ())
    }
}

fn extents() -> [Extent; 3] {
    [Extent { first_block: 100, block_count: 1 },
     Extent { first_block: 104, block_count: 1 },
     Extent { first_block: 108, block_count: 1 }]
}

pub fn run(boot: &BootData, allocator: &mut memory::FrameAllocator)
    -> Result<(), &'static str> {
    let frames_before = allocator.remaining_pages();
    let file = File::validate(extents(), 1300, 2048)
        .map_err(|_| "k1615-extents")?;
    if file.extents() != extents() || file.size() != 1300 {
        return Err("k1615-descriptor");
    }
    write_line("TURKOS/OS/K1615-EXTENTS: THREE=ORDERED");
    let mut overlap = extents();
    overlap[1].first_block = 100;
    if File::validate(overlap, 1300, 2048) != Err(Error::Overlap) {
        return Err("k1615-overlap");
    }
    write_line("TURKOS/OS/K1615-EXTENTS: OVERLAP=REJECTED");

    let mut disk = virtio_ro_turkfs::RoDisk::open(
        boot, allocator, "TURKOS/OS/K1615-GET")?;
    if disk.capacity() != 2048 {
        return Err("k1615-capacity");
    }
    let mut output = [0xa5u8; 1301];
    let read = file.read_all(&mut Transport(&mut disk), &mut output);
    disk.close(allocator)?;
    if read != Ok(1300) || output[1300] != 0xa5 {
        return Err("k1615-read");
    }
    let digest = turkos_kernel::turkfs::file_sha256(&output[..1300]);
    let hex = turkos_kernel::program_hash::hex_lower(&digest);
    if &hex != EXPECTED_SHA256 {
        return Err("k1615-hash");
    }
    write_line("TURKOS/OS/K1615-READ: SHA256=5ab4d3c0b1612817d6c4335036f9445aead46ff52ff5ae3a00d4245b98582854");
    if allocator.remaining_pages() != frames_before {
        return Err("k1615-frames");
    }
    write_line("TURKOS/OS/K1615-READ: BYTES=1300 FRAMES=UNCHANGED");
    Ok(())
}