use super::*;
use std::{
    path::{Path,PathBuf,},
};

impl ProcessArgs
{
    pub fn parse<T, U>(string: &mut T, not_last: &mut bool) -> Result<Self, &'static str>
    where T: Iterator<Item=U>,
	  U: AsRef<str>
    {
	let name = string.next().ok_or("No process name")?.as_ref().to_owned();
	let mut args = Vec::new();
	*not_last = false;
	while let Some(arg) = string.next() {
	    let arg = arg.as_ref();
	    let mut chars = arg.chars();
	    if let Some(BROKEN_PIPE) = chars.next() {
		*not_last = true;
		break;
	    } else {
		args.push(arg.to_owned());
	    }
	}

	Ok(Self{
	    name,
	    args,
	    name_real: None,
	})
    }

    pub fn name_path(&self) -> Result<&Path, &'static str>
    {
	if let Some(buf) = &self.name_real {
	    Ok(buf.as_ref())
	} else {
	    Err("No name_path specified, have you called `verify()`?")
	}
    }

    pub fn verify(&self) -> Result<PathBuf, &'static str>
    {
	if let Ok(spath) = std::env::var("LEAKY_PIPE_PATH") {
	    if let Some(path) = find_somewhere(&self.name, spath.split(':')) {
		return Ok(path)
	    }
	}
	
	if let Ok(spath) = std::env::var("PATH") {
	    if let Some(path) = find_somewhere(&self.name, spath.split(':')) {
		Ok(path)
	    } else {
		Err("File not found")
	    }
	} else {
	    match Path::new(&self.name) {
		path if path.exists() => Ok(Path::new(&self.name).to_owned()),
		_ => Err("File not found and $PATH not found.")
	    }
	}
    }
}

fn find_somewhere<T,U,V>(name: T, places: U) -> Option<PathBuf>
where T: AsRef<str>,
      U: IntoIterator<Item=V>,
      V: AsRef<str>
{
    let name = name.as_ref();
    
    for place in places.into_iter()
    {
	let place = place.as_ref();

	let pbuf = Path::new(&place).join(&name);
	if pbuf.exists() {
	    return Some(pbuf);   
	}
    }

    None
}

fn escape<T>(s: &T) -> String
where T: AsRef<str> + ?Sized
{
    let s = s.as_ref();
    let mut o = String::with_capacity(s.len());

    for c in s.chars() {
	match c {
	    '\\' => {
		o.push('\\');
		o.push('\\');
	    },
	    '\'' => {
		o.push('\\');
		o.push('\'');
	    },
	    other => o.push(other),
	};
    }

    o
}

use std::fmt;
impl fmt::Display for ProcessArgs
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
    {
	write!(f, "{} ", self.name)?;
	let len = self.args.len();
	for (i,x) in (0..len).zip(self.args.iter()) {
	    write!(f, "{}", &x)?;
	    if i < len-1 {
		write!(f, " ")?;
	    }
	}

	Ok(())
    }
}