#[repr(u16)]
pub enum KTaskRequestType {
    DoNothing = 0,
    /// prints a message to the terminal greeting the user (:
    SayHi = 1,
    /// readies the filesystem for use
    /// takes a FileSystem struct as defined in crate::fs, this struct contains unknown members.
    /// that depend on what hbd filesystem the kernel was compiled with, but will always be 32 bytes.
    /// it's probably best to stack allocate it in the calling procees.
    /// 0 indicates success, 1 indicates failure
    FSOpen = 2,
    /// takes a string, interprets it as an absolute filesystem path, and opens it as a directory reader.
    /// requires a previous call to FSOpen.
    /// 0 indicates success,
    /// 1 = directory not found
    /// 2 = invalid record (i.e. you tried to open a file as a directory)
    /// 3 = user error (you probably didn't prefix the path with '/')
    FSOpenDir = 3,
    /// takes a directory reader and an empty record struct, and reads one record from the directory into it.
    /// requires a previous call to FSOpenDir
    /// 0 = success
    /// 1 = end of directory
    /// 2 = other error
    FSReadDir = 4,
    /// takes a file record and an empty file reader struct, and readies the file reader struct for reading
    /// requires a previous call to fsopen
    /// 0 = success
    /// 1 = failure
    FSOpenFile = 5,
    /// reads data from the file reader into the provided buffer, until either the buffer is full or the file is at the end.
    /// requires a previous call to FSOpenFile
    /// returns success on all calls, including the last one; if EOF is reached, the buffer was not touched
    /// 0 = success
    /// 1 = end of file
    /// 2 = other error
    FSReadFile = 6,
    /// seeks forward N sectors in the file.
    /// requires a previous call to FSOpenFile
    /// 0 = success
    /// 1 = failure (i.e. cannot seek due to EOF)
    FSSeek = 7,
    /// given a DDI file buffer, loads the file into memory and returns the required information to execute it
    /// after loading, you can free the file buffer without concern
    /// 0 = success
    /// 1 = failure
    LoadDDIFile = 8,
}

#[repr(C)]
pub struct KTaskRequest {
    pub req: u16,
    pub replyto: u8,
    pub retval: u32,
}

#[repr(C)]
pub struct KTaskFSOpenRequest {
    pub base: KTaskRequest,
    pub fs: *mut crate::fs::FileSystem,
}

#[repr(C)]
pub struct KTaskFSOpenDirRequest {
    pub base: KTaskRequest,
    pub fs: *const crate::fs::FileSystem,
    pub dir: *mut crate::fs::DirectoryReader,
    pub path: *const u8,
    pub pathlen: u32,
}

#[repr(C)]
pub struct KTaskFSReadDirRequest {
    pub base: KTaskRequest,
    pub fs: *const crate::fs::FileSystem,
    pub dir: *mut crate::fs::DirectoryReader,
    pub record: *mut crate::fs::Record,
}

#[repr(C)]
pub struct KTaskFSOpenFileRequest {
    pub base: KTaskRequest,
    pub fs: *const crate::fs::FileSystem,
    pub record: *const crate::fs::Record,
    pub reader: *mut crate::fs::FileReader,
}

#[repr(C)]
pub struct KTaskFSReadFileRequest {
    pub base: KTaskRequest,
    pub fs: *const crate::fs::FileSystem,
    pub reader: *mut crate::fs::FileReader,
    pub buffer: *mut u8,
    pub bufferlen: u32,
}

#[repr(C)]
pub struct KTaskFSSeek {
    pub base: KTaskRequest,
    pub fs: *const crate::fs::FileSystem,
    pub reader: *mut crate::fs::FileReader,
    pub sectors: u32,
}

#[repr(C)]
pub struct KTaskLoadDDIFile {
    pub base: KTaskRequest,
    pub file_buf_pointer: usize,
    pub file_buf_len: usize,
    pub task_setup_ptr: usize,
}

pub fn request_type_from_req(req: u16) -> KTaskRequestType {
    match req {
        0 => KTaskRequestType::DoNothing,
        1 => KTaskRequestType::SayHi,
        2 => KTaskRequestType::FSOpen,
        3 => KTaskRequestType::FSOpenDir,
        4 => KTaskRequestType::FSReadDir,
        5 => KTaskRequestType::FSOpenFile,
        6 => KTaskRequestType::FSReadFile,
        7 => KTaskRequestType::FSSeek,
        8 => KTaskRequestType::LoadDDIFile,
        _ => KTaskRequestType::DoNothing,
    }
}

pub fn query_ktask(req: usize) {
    crate::syscalls::send_notification(0, req);
    crate::syscalls::wait_for_notif_ack(0);
    let tmp = crate::syscalls::wait_for_notification();
    if tmp != req {
        crate::syscalls::write_terminal(b"ktask failed to respond properly!\n");
    }
}

pub fn ktask_sayhi() {
    let ci = crate::syscalls::current_task();
    let req = crate::syscalls::alloc_blocks(1);
    {
        let req = unsafe { &mut *(req as *mut KTaskRequest) };
        req.req = KTaskRequestType::SayHi as u16;
        req.replyto = ci;
    }
    query_ktask(req);
    crate::syscalls::free_blocks(req, 1);
}

pub fn ktask_fsopen(fs: &mut crate::fs::FileSystem) -> usize {
    let ci = crate::syscalls::current_task();
    let req = crate::syscalls::alloc_blocks(1);
    {
        let req = unsafe { &mut *(req as *mut KTaskFSOpenRequest) };
        req.base.req = KTaskRequestType::FSOpen as u16;
        req.base.replyto = ci;
        req.fs = fs as *mut _;
    }
    query_ktask(req);
    let retval = {
        let req = unsafe { &mut *(req as *mut KTaskFSOpenRequest) };
        req.base.retval
    };
    crate::syscalls::free_blocks(req, 1);
    retval as usize
}

pub fn ktask_fsopendir(
    fs: &crate::fs::FileSystem,
    dir: &mut crate::fs::DirectoryReader,
    path: &[u8],
) -> usize {
    let ci = crate::syscalls::current_task();
    let req = crate::syscalls::alloc_blocks(1);
    {
        let req = unsafe { &mut *(req as *mut KTaskFSOpenDirRequest) };
        req.base.req = KTaskRequestType::FSOpenDir as u16;
        req.base.replyto = ci;
        req.fs = fs as *const _;
        req.dir = dir as *mut _;
        req.path = path.as_ptr();
        req.pathlen = path.len() as u32;
    }
    query_ktask(req);
    let retval = {
        let req = unsafe { &mut *(req as *mut KTaskFSOpenDirRequest) };
        req.base.retval
    };
    crate::syscalls::free_blocks(req, 1);
    retval as usize
}

pub fn ktask_fsreaddir(
    fs: &crate::fs::FileSystem,
    dir: &mut crate::fs::DirectoryReader,
    record: &mut crate::fs::Record,
) -> usize {
    let ci = crate::syscalls::current_task();
    let req = crate::syscalls::alloc_blocks(1);
    {
        let req = unsafe { &mut *(req as *mut KTaskFSReadDirRequest) };
        req.base.req = KTaskRequestType::FSReadDir as u16;
        req.base.replyto = ci;
        req.fs = fs as *const _;
        req.dir = dir as *mut _;
        req.record = record as *mut _;
    }
    query_ktask(req);
    let retval = {
        let req = unsafe { &mut *(req as *mut KTaskFSReadDirRequest) };
        req.base.retval
    };
    crate::syscalls::free_blocks(req, 1);
    retval as usize
}

pub fn ktask_fsopenfile(
    fs: &crate::fs::FileSystem,
    record: &crate::fs::Record,
    reader: &mut crate::fs::FileReader,
) -> usize {
    let ci = crate::syscalls::current_task();
    let req = crate::syscalls::alloc_blocks(1);
    {
        let req = unsafe { &mut *(req as *mut KTaskFSOpenFileRequest) };
        req.base.req = KTaskRequestType::FSOpenFile as u16;
        req.base.replyto = ci;
        req.fs = fs as *const _;
        req.record = record as *const _;
        req.reader = reader as *mut _;
    }
    query_ktask(req);
    let retval = {
        let req = unsafe { &mut *(req as *mut KTaskFSOpenFileRequest) };
        req.base.retval
    };
    crate::syscalls::free_blocks(req, 1);
    retval as usize
}

pub fn ktask_fsreadfile(
    fs: &crate::fs::FileSystem,
    reader: &mut crate::fs::FileReader,
    buffer: &mut [u8],
) -> usize {
    let ci = crate::syscalls::current_task();
    let req = crate::syscalls::alloc_blocks(1);
    {
        let req = unsafe { &mut *(req as *mut KTaskFSReadFileRequest) };
        req.base.req = KTaskRequestType::FSReadFile as u16;
        req.base.replyto = ci;
        req.fs = fs as *const _;
        req.reader = reader as *mut _;
        req.buffer = buffer.as_mut_ptr();
        req.bufferlen = buffer.len() as u32;
    }
    query_ktask(req);
    let retval = {
        let req = unsafe { &mut *(req as *mut KTaskFSReadFileRequest) };
        req.base.retval
    };
    crate::syscalls::free_blocks(req, 1);
    retval as usize
}

pub fn ktask_fsseek(
    fs: &crate::fs::FileSystem,
    reader: &mut crate::fs::FileReader,
    sectors: u32,
) -> usize {
    let ci = crate::syscalls::current_task();
    let req = crate::syscalls::alloc_blocks(1);
    {
        let req = unsafe { &mut *(req as *mut KTaskFSSeek) };
        req.base.req = KTaskRequestType::FSSeek as u16;
        req.base.replyto = ci;
        req.fs = fs as *const _;
        req.reader = reader as *mut _;
        req.sectors = sectors;
    }
    query_ktask(req);
    let retval = {
        let req = unsafe { &mut *(req as *mut KTaskFSSeek) };
        req.base.retval
    };
    crate::syscalls::free_blocks(req, 1);
    retval as usize
}

pub fn ktask_loadddifile(
    file_buf_pointer: usize,
    file_buf_len: usize,
    task_setup_ptr: usize,
) -> usize {
    let ci = crate::syscalls::current_task();
    let req = crate::syscalls::alloc_blocks(1);
    {
        let req = unsafe { &mut *(req as *mut KTaskLoadDDIFile) };
        req.base.req = KTaskRequestType::LoadDDIFile as u16;
        req.base.replyto = ci;
        req.file_buf_pointer = file_buf_pointer;
        req.file_buf_len = file_buf_len;
        req.task_setup_ptr = task_setup_ptr;
    }
    query_ktask(req);
    let retval = {
        let req = unsafe { &mut *(req as *mut KTaskLoadDDIFile) };
        req.base.retval
    };
    crate::syscalls::free_blocks(req, 1);
    retval as usize
}