#![allow(dead_code)]

pub const BUFFER_SIZE: usize = 4096;

#[macro_use]
mod log;
mod bytes;
mod ext;
pub use ext::*;
mod error;
mod hash;
mod container;
mod config;
mod arg;
mod proc;

//#[cfg(feature="threads")]
//mod pipe; //No longer needed

#[cfg(test)]
mod test {
    use super::*;
    use std::{
	path::Path,
    };

    #[test]
    pub fn args() -> Result<(), arg::Error>
    {
	macro_rules! string_literal {
	    ($($strings:expr),*) => {
		vec![$(
		    format!($strings),
		)*]
	    }
	}
	let args = string_literal!["-lsd", "--load-file", "hello", "--load-save", "load-save!", "--", "test-input", "test-input", "test-input-3", "test-input-2"];
	println!("{:?}", arg::parse(args)?);
	Ok(())
    }
    
    #[test]
    pub fn test() -> Result<(), error::Error>
    {
	let mut cont = container::DupeMap::new();
	let mode = config::Mode::default();
	let path = Path::new("test-input");

	assert_eq!(proc::DupeCount{total:4, dupes:2}, proc::do_dir(path, 0, &mut cont, &mode)?);

	Ok(())
    }

    #[cfg(feature="threads")]
    pub async fn _test_async() -> Result<(), error::Error>
    {
	use std::sync::Arc;
	use tokio::{
	    sync::Mutex,
	};
	let cont = Arc::new(Mutex::new(container::DupeMap::new()));
	let mode = config::Mode::default();
	let path = Path::new("test-input");

	assert_eq!(proc::DupeCount{total:4, dupes:2}, proc::do_dir_async(path, 0, cont, mode, None).await?);

	Ok(())
    }
    #[cfg(feature="threads")]
    #[test]
    pub fn test_async() -> Result<(), error::Error>
    {
	tokio_test::block_on(_test_async())
    }
}


#[inline]
fn absolute(path: impl AsRef<std::path::Path>) -> std::path::PathBuf
{
    std::fs::canonicalize(path).expect("Invalid path internal")
}

#[cfg(feature="threads")]
async fn rebase_one_async(path: impl AsRef<std::path::Path>, hash: hash::Sha256Hash, semaphore: Option<std::sync::Arc<tokio::sync::Semaphore>>) -> Result<Option<(std::path::PathBuf, hash::Sha256Hash)>, error::Error>
{
    use std::{
	convert::TryInto,
    };
    use tokio::{
	fs::{
	    OpenOptions,
	},
    };
    let path = path.as_ref();
    let _lock = match semaphore {
	Some(sem) => Some(sem.acquire_owned().await),
	None => None,
    };
    let mut file = OpenOptions::new()
	.read(true)
	.open(path).await?;
    let sz: usize = file.metadata().await?.len().try_into().or(Err(error::Error::Arch(Some("Filesize is too large to be known. you have likely compiled the binary for 32-bit architecture or less. This shouldn't happen on 64-bit systems."))))?;
    let mut result = hash::Sha256Hash::default();
    error::check_size(sz, hash::compute_async(&mut file, &mut result).await?)?;

    println!("Computed {:?}", path);
    if hash != result {
	Ok(Some((path.to_owned(), result)))
    } else {
	Ok(None)
    }
}

#[cfg(feature="threads")]
async fn rebase(config: config::Rebase) -> Result<(), Box<dyn std::error::Error>>
{
    use std::{
	path::{
	    Path,
	},
	sync::Arc,
    };
    use tokio::{
	fs::{
	    OpenOptions,
	},
	sync::Semaphore,
    };
    let mut hashes = container::DupeMap::new();
    for (transient, load) in config.load.iter().map(|x| (false, x)).chain(config.save.iter().map(|x| (true, x)))
    {
	let load = Path::new(load);
	if load.exists() {
	    if load.is_file() {
		if let Ok(mut file) = OpenOptions::new()
		    .read(true)
		    .open(load).await
		{
		    match hashes.load_async(&mut file, transient).await {
			Err(e) if !transient=> return Err(format!("Failed to load required {:?}: {}", file, e))?,
			_ => (),
		    };
		}
	    }
	}
    }

    let mut remove = Vec::new();
    let mut children = Vec::with_capacity(hashes.cache_len());
    let semaphore = config.max_threads.map(|num| Arc::new(Semaphore::new(num.into())));
    for (path, (hash, trans)) in hashes.cache_iter()
    {
	if !trans { //Don't rebuild transient ones, this is desired I think? Maybe not... Dunno.
	    if path.exists() && path.is_file() {
		//Getting hash
		let path = path.clone();
		let hash = *hash;
		let semaphore = semaphore.as_ref().map(|semaphore| Arc::clone(semaphore));
		children.push(tokio::task::spawn(async move {
		    rebase_one_async(path, hash, semaphore).await
		}));
	    } else {
		remove.push(path.clone());
	    }
	}
    }

    let (mut changed, mut removed) = (0usize, 0usize);
    for child in children.into_iter()
    {
	if let Some((path, hash)) = child.await.expect("Child panic")?
	{
	    println!("Updating {:?} -> {}", path, hash);
	    hashes.cache_force(path, hash, false);
	    changed +=1;
	}
    }
    for remove in remove.into_iter()
    {
	println!("Removing {:?}", remove);
	hashes.uncache(remove);
	removed +=1;
    }

    println!("Updated. {} changed, {} removed.", changed, removed);

    // Save the hashes set in concurrently to each file.
    let hashes = Arc::new(hashes);
    futures::future::join_all(config.save.iter().map(|save| {
	let hashes = hashes.clone();
	let save = save.to_owned();
	tokio::task::spawn(async move {
	    let save = Path::new(&save);
	    let mut file = match OpenOptions::new()
		.create(true)
		.truncate(true)
		.write(true)
		.open(&save).await {
		    Ok(v) => v,
		    Err(e) => {println!("Warning: Failed to open output {:?}, ignoring: {}", save, e); return;},
		};
	    
	    match hashes.save_async(&mut file).await {
		Err(e) => println!("Warning: Failed to write to output {:?}: ignoring: {}", file, e),
		_ => (),
	    };
	    match file.sync_data().await {
		Err(e) => println!("Warning: Failed to sync output {:?}: ignoring: {}", file, e),
		_ => (),
	    }
	})
    })).await;
    
    Ok(())
}

#[cfg(not(feature="threads"))]
fn rebase(config: config::Rebase) -> Result<(), Box<dyn std::error::Error>>
{
    todo!()
}


fn parse_args() -> Result<arg::Output, error::Error>
{
    match arg::parse_args()? {
	arg::Output::Help => arg::usage(),
	conf => Ok(conf),
    }
}

#[cfg_attr(feature="threads", tokio::main)]
#[cfg(feature="threads")]
async fn main() -> Result<(), Box<dyn std::error::Error>>
{
    use tokio::{
	fs::{
	    OpenOptions,
	},
	sync::{
	    Mutex
	},
    };
    use std::{
	path::Path,
	sync::Arc,
    };
    
    match parse_args().into_string()? {
	arg::Output::Rebase(r) => {
	    return rebase(r).await;
	},
	arg::Output::Normal(args) => {
	    let lmode = &args.mode.logging_mode;

	    log!(Debug, lmode => "Args parsed: {:?}", args);

	    let mut children = Vec::new();

	    let mut hashes = container::DupeMap::new();

	    // Load hashes
	    for (transient, load) in args.load.iter().map(|x| (false, x)).chain(args.save.iter().map(|x| (true, x)))
	    {
		let load = Path::new(load);
		if load.exists() {
		    if load.is_file() {
			if let Some(mut file) = OpenOptions::new()
			    .read(true)
			    .open(load).await.log_and_forget(lmode, log::Level::Warning)?
			{
			    log!(Info, lmode => "Hashes loading from {:?}", load);
			    args.mode.error_mode.handle(hashes.load_async(&mut file, transient).await).log_and_forget(lmode, if transient {log::Level::Info} else {log::Level::Warning})?;
			}
		    } else {
			log!(Warning, lmode => "Exclusing directory from load path {:?}", load);
		    }
		} else {
		    log!(Info, lmode => "Ignoring non-existant load path {:?}", load);
		}
	    }

	    log!(Debug, lmode => "Loaded hashes: {}", hashes);
	    log!(Info, lmode => "Starting checks (threaded)");
	    let hashes = Arc::new(Mutex::new(hashes));
	    let semaphore = args.max_threads.map(|num| Arc::new(tokio::sync::Semaphore::new(num.into())));
	    for path in args.paths.iter()
	    {
		let path = Path::new(path);
		if path.is_dir() {
		    log!(Debug, lmode => "Spawning for {:?}", path);
		    let mode = args.mode.clone();
		    let path = absolute(&path);
		    let hashes= Arc::clone(&hashes);
		    let semaphore = semaphore.as_ref().map(|sem| Arc::clone(sem));
		    children.push(tokio::task::spawn(async move {
			log!(Debug, mode.logging_mode => " + {:?}", path);
			let res = mode.error_mode.handle(proc::do_dir_async(path.clone(), 0, hashes, mode.clone(), semaphore).await).log_and_forget(&mode.logging_mode, log::Level::Error);
			log!(Info, mode.logging_mode => " - {:?}", path);
			res
		    }));
		}
	    }
	    log!(Info, lmode => "Waiting on children");
	    let mut done = proc::DupeCount::default();
	    for child in children.into_iter()
	    {
		done += args.mode.error_mode.handle(child.await?)?.unwrap_or_default().unwrap_or_default().unwrap_or_default();
	    }
	    log!(Info, lmode => "Found: {:?}", done);
	    
	    let hashes = hashes.lock().await;
	    log!(Debug, lmode => "New hashes: {}", hashes);

	    for save in args.save.iter()
	    {
		let save = Path::new(save);
		log!(Info, lmode => "Saving hashes to {:?}", save);
		if let Some(mut file) = OpenOptions::new()
		    .create(true)
		//.append(true)
		    .truncate(true)
		    .write(true)
		    .open(save).await.log_and_forget(lmode, log::Level::Warning)?
		{
		    args.mode.error_mode.handle(hashes.save_async(&mut file).await).log_and_forget(lmode, log::Level::Warning)?;
		    use tokio::prelude::*;
		    file.shutdown().await.log_and_forget(lmode, log::Level::Warning)?; //One of these is probably redundant.
		    file.sync_data().await.log_and_forget(lmode, log::Level::Warning)?;
		}
	    }
	},
	_ => unreachable!(),
    };
    
    Ok(())
}

#[cfg(not(feature="threads"))]
fn main() -> Result<(), Box<dyn std::error::Error>>
{
    use std::{
	path::Path,
	fs::{
	    OpenOptions,
	},
    };
    let args = parse_args().into_string()?;
    let lmode = &args.mode.logging_mode;

    log!(Debug, lmode => "Args parsed: {:?}", args);

    let mut hashes = container::DupeMap::new();

    // Load hashes
    for load in args.load.iter()
    {
	let load = Path::new(load);
	if load.exists() {
	    if load.is_file() {
		if let Some(mut file) = OpenOptions::new()
		    .read(true)
		    .open(load).log_and_forget(lmode, log::Level::Warning)?
		{
		    log!(Info, lmode => "Hashes loading from {:?}", load);
		    args.mode.error_mode.handle(hashes.load(&mut file)).log_and_forget(lmode, log::Level::Warning)?;
		}
	    } else {
		log!(Warning, lmode => "Exclusing directory from load path {:?}", load);
	    }
	} else {
	    log!(Info, lmode => "Ignoring non-existant load path {:?}", load);
	}
    }

    log!(Debug, lmode => "Loaded hashes: {:?}", hashes);
    log!(Info, lmode => "Starting checks (threaded)");

    let mut done = proc::DupeCount::default();
    for path in args.paths.iter()
    {
	let path = Path::new(path);
	if path.is_dir() {
	    log!(Debug, lmode => " + {:?}", path);
	    done += args.mode.error_mode.handle(proc::do_dir(path.clone(), 0, &mut hashes, &args.mode)).log_and_forget(lmode, log::Level::Error)?.unwrap_or_default().unwrap_or_default();
	    log!(Info, lmode => " - {:?}", path);
	}
    }

    log!(Info, lmode => "Found: {:?}", done);
    log!(Debug, lmode => "New hashes: {}", hashes);

    for save in args.save.iter()
    {
	let save = Path::new(save);
	log!(Info, lmode => "Saving hashes to {:?}", save);
	if let Some(mut file) = OpenOptions::new()
	    .create(true)
	//.append(true)
	    .truncate(true)
	    .write(true)
	    .open(save).log_and_forget(lmode, log::Level::Warning)?
	{
	    args.mode.error_mode.handle(hashes.save(&mut file)).log_and_forget(lmode, log::Level::Warning)?;
	}
    }
    
    Ok(())
}