use std::fs::File;
use std::io;
use std::io::BufRead;
use std::collections::HashMap;

/**
  Represents a CSV file 
  **/

pub struct CsvFile {
	path : String,
	delim : String,
	pub header : Vec<String>,
	pub content : Vec<Vec<String>>,
	has_header : bool
}

/*
 * Iterator for the CSV file
 */
pub struct CsvFileIterator<'a> {
	file : &'a CsvFile,
	line : usize,
	column : usize,
	max_column : usize
}

impl <'a> Iterator for CsvFileIterator<'a> {
	type Item = HashMap<&'a String,&'a String>;

	fn next(&mut self) -> Option<Self::Item> {
		let k = self.file.content.get(self.line)?;
		let it : HashMap<&'a String, &'a String> = self.file.header.iter().zip(k.iter()).collect();
		self.line = self.line + 1;
		Some(it)
	}
}

impl CsvFile {
	pub fn new(path: &str, delim: &str, header: bool) -> CsvFile {
		CsvFile {
			path : String::from(path),
			delim: String::from(delim),
			header : Vec::new(),
			content : Vec::new(),
			has_header : header 
		}

	}

	// TODO nicht gleich viele spalten
	fn parse_line(line : String, delim: &str) -> Vec<String> {
		let mut columns : Vec<String> = Vec::new();
		for column in line.split(delim).collect::<Vec<&str>>() {
			columns.push(column.trim_matches(|c| c == '\'' || c == '\"').to_string());
		}
		columns
	}


	pub fn from_file(path: &str, delim: &str, header: bool) -> Result<CsvFile, io::Error> {
		let fd = File::open(path)?;
		let reader = io::BufReader::new(fd);
		let mut column_names : Vec<String> = Vec::new();
		let mut lines : Vec<Vec<String>> = Vec::new();
		let mut first = true;
		
		for line in reader.lines() {
			let line = line?;
			if header && first {
				column_names.append(&mut CsvFile::parse_line(line, delim));
				first = false;
			} else {
				lines.push(CsvFile::parse_line(line, delim));
			}
		}
		
		Ok(CsvFile { path: String::from(path),
			     delim : String::from(delim),
			     header : column_names,
			     content : lines,
			     has_header: header } )
	}

	pub fn iter(&self) -> CsvFileIterator {
		CsvFileIterator { file : self,
			line : 0,
			column : 0,
			max_column : self.header.len()
		}
	}

}