use super::*;
use std::{
    hash::Hash,
    collections::{HashSet, HashMap},
    mem,
    fmt,
};

pub trait DedupFullExt
{
    fn dedup_full(&mut self);
}

impl<T> DedupFullExt for Vec<T>
where T: Hash + Default + Eq
{
    fn dedup_full(&mut self)
    {
	let mut set: HashMap<T, usize> = HashMap::new();
	for (i,x) in (0..).zip(self.iter_mut())
	{
	    if !set.contains_key(x) {
		let us = mem::replace(x, Default::default());
		set.insert(us, i);
	    }
	}
	// To preserve order:
	let mut tmp = Vec::with_capacity(self.len());
	for item in set.into_iter()
	{
	    tmp.push(item);
	}
	tmp.sort_by(move |a, b| a.1.partial_cmp(&b.1).unwrap());
	self.truncate(tmp.len());
	for (d,s) in self.iter_mut().zip(tmp.into_iter())
	{
	    *d = s.0;
	}
    }
}
pub trait ErrorLogForgetExt<T, E>: Sized
{
    fn log_and_forget(self, mode: &log::Mode, level: log::Level) -> Option<T>;
}
impl<T,E> ErrorLogForgetExt<T,E> for Result<T,E>
where E: fmt::Display,
{
    fn log_and_forget(self, mode: &log::Mode, level: log::Level) -> Option<T>
    {	
	match self {
	    Err(e) => {
		log!(mode.level(level), "{}", &e);
		if let log::Level::Fatal = level {
		    std::process::exit(1);
		}
		None
	    },
	    Ok(v) => Some(v),
	}
    }
}
pub trait ErrorLogExt: Sized
{
    fn into_log(self, mode: &log::Mode, level: log::Level) -> Self;
    fn into_fatal(self, mode: Option<log::Mode>) -> Self
    {
	self.into_log(&mode.unwrap_or(log::Mode::Verbose), log::Level::Fatal)
    }
}

impl<T,E> ErrorLogExt for Result<T,E>
where E: fmt::Display
{
    fn into_log(self, mode: &log::Mode, level: log::Level) -> Self
    {
	match self {
	    Err(e) => {
		log!(mode.level(level), "{}", &e);
		if let log::Level::Fatal = level {
		    std::process::exit(1);
		}
		Err(e)
	    },
	    Ok(v) => Ok(v),
	}
    }
}

pub trait ErrorExt<T>
{
    fn into_string(self) -> Result<T, String>;
}

impl<T,E> ErrorExt<T> for Result<T,E>
where E: fmt::Display
{
    fn into_string(self) -> Result<T, String>
    {
	match self {
	    Ok(v) => Ok(v),
	    Err(e) => Err(format!("{}", e)),
	}
    }
}

#[cfg(test)]
mod test
{
    use super::*;

    #[test]
    fn dedup_full()
    {
	let mut vec = vec![
	    "hello",
	    "how",
	    "are",
	    "you",
	    "hello",
	    "hello",
	    "today",
	    "today",
	    "you",
	    "how",
	    "hello",
	];

	vec.dedup_full();
	
	assert_eq!(vec.len(), 5);
	assert_eq!(&vec[..], &["hello","how", "are", "you", "today"]);
    }
}