use nom::
{
	IResult,
	branch::alt,
	bytes::complete::{escaped_transform, tag},
	character::complete::{digit1, none_of},
	combinator::{map, map_res, opt, recognize},
	sequence::{delimited, pair, terminated},
};

use super::word_boundary;

pub fn integer(i: &str) -> IResult<&str, crate::Term>
{
	map
	(
		map_res
		(
			recognize
			(
				terminated
				(
					pair
					(
						opt
						(
							alt
							((
								tag("-"),
								tag("+"),
							))
						),
						digit1,
					),
					word_boundary,
				)
			),
			std::str::FromStr::from_str,
		),
		crate::Term::integer,
	)(i)
}

fn infimum(i: &str) -> IResult<&str, crate::Term>
{
	map
	(
		terminated
		(
			tag("#inf"),
			word_boundary,
		),
		|_| crate::Term::infimum(),
	)(i)
}

fn supremum(i: &str) -> IResult<&str, crate::Term>
{
	map
	(
		terminated
		(
			tag("#sup"),
			word_boundary,
		),
		|_| crate::Term::supremum(),
	)(i)
}

pub fn special_integer(i: &str) -> IResult<&str, crate::Term>
{
	alt
	((
		infimum,
		supremum,
	))(i)
}

pub fn string(i: &str) -> IResult<&str, crate::Term>
{
	map
	(
		terminated
		(
			delimited
			(
				tag("\""),
				escaped_transform
				(
					none_of("\"\\"),
					'\\',
					alt
					((
						tag("\""),
						tag("\\"),
						map
						(
							tag("n"),
							|_| "\n",
						),
						map
						(
							tag("t"),
							|_| "\t",
						),
					)),
				),
				tag("\""),
			),
			word_boundary,
		),
		crate::Term::string,
	)(i)
}

/*
fn function<'a>(i: &'a str, declarations: &Declarations) -> IResult<&'a str, crate::Formula>
{
	alt
	((
		function_n_ary,
		function_0_ary
	))(i)
}

fn function_0_ary<'a>(i: &'a str, declarations: &Declarations) -> IResult<&'a str, crate::Term>
{
	map
	(
		delimited(multispace0, function_identifier, multispace0),
		|name| crate::Formula::function(
			crate::FunctionDeclaration
			{
				name: name,
				arity: 0,
			},
			vec![])
	)(i)
}

fn function_n_ary<'a>(i: &'a str, declarations: &Declarations) -> IResult<&'a str, crate::Term>
{
	map
	(
		pair
		(
			delimited(multispace0, function_identifier, multispace0),
			delimited
			(
				multispace0,
				delimited
				(
					tag("("),
					separated_list(tag(","), term),
					tag(")")
				),
				multispace0
			)
		),
		|(name, arguments)| crate::Formula::function(
			crate::PredicateDeclaration
			{
				name: name,
				arity: arguments.len(),
			},
			arguments)
	)(i)
}

*/

#[cfg(test)]
mod tests
{
	use crate::parse::*;
	use crate::Term;

	#[test]
	fn parse_integer()
	{
		assert_eq!(integer("0"), Ok(("", Term::integer(0))));
		assert_eq!(integer("10000"), Ok(("", Term::integer(10000))));
		assert_eq!(integer("+10000"), Ok(("", Term::integer(10000))));
		assert_eq!(integer("-10000"), Ok(("", Term::integer(-10000))));
		assert_eq!(integer("0 42"), Ok((" 42", Term::integer(0))));
		assert_eq!(integer("10000 42"), Ok((" 42", Term::integer(10000))));
		assert_eq!(integer("+10000 42"), Ok((" 42", Term::integer(10000))));
		assert_eq!(integer("-10000 42"), Ok((" 42", Term::integer(-10000))));
		assert_eq!(integer("10000,"), Ok((",", Term::integer(10000))));
		assert_eq!(integer("+10000,"), Ok((",", Term::integer(10000))));
		assert_eq!(integer("-10000,"), Ok((",", Term::integer(-10000))));
		assert!(integer("10000a").is_err());
		assert!(integer("+10000a").is_err());
		assert!(integer("-10000a").is_err());
		assert!(integer("1.5").is_err());
		assert!(integer("a").is_err());
		assert!(integer("-").is_err());
		assert!(integer(" ").is_err());
	}

	#[test]
	fn parse_special_integer()
	{
		assert_eq!(special_integer("#inf"), Ok(("", Term::infimum())));
		assert_eq!(special_integer("#sup"), Ok(("", Term::supremum())));
		assert_eq!(special_integer("#inf #sup"), Ok((" #sup", Term::infimum())));
		assert_eq!(special_integer("#sup #inf"), Ok((" #inf", Term::supremum())));
		assert_eq!(special_integer("#inf,"), Ok((",", Term::infimum())));
		assert_eq!(special_integer("#sup,"), Ok((",", Term::supremum())));
		assert!(special_integer("#inf0").is_err());
		assert!(special_integer("#sup0").is_err());
		assert!(special_integer("#infimum").is_err());
		assert!(special_integer("#supremum").is_err());
		assert!(special_integer("inf").is_err());
		assert!(special_integer("sup").is_err());
		assert!(special_integer("0").is_err());
		assert!(special_integer("10000").is_err());
		assert!(special_integer("-10000").is_err());
		assert!(special_integer(" ").is_err());
	}

	#[test]
	fn parse_string()
	{
		assert_eq!(string("\"test 123\""), Ok(("", Term::string("test 123".to_string()))));
		assert_eq!(string("\"123 test\""), Ok(("", Term::string("123 test".to_string()))));
		assert_eq!(string("\" test 123 \""), Ok(("", Term::string(" test 123 ".to_string()))));
		assert_eq!(string("\"test 123\" \"rest"), Ok((" \"rest", Term::string("test 123".to_string()))));
		assert_eq!(string("\"test 123\", \"rest"), Ok((", \"rest", Term::string("test 123".to_string()))));
		assert_eq!(string("\"test\n123\""), Ok(("", Term::string("test\n123".to_string()))));
		assert_eq!(string("\"test\\\"123\""), Ok(("", Term::string("test\"123".to_string()))));
		assert_eq!(string("\"test\\\"123\\\"\""), Ok(("", Term::string("test\"123\"".to_string()))));
		assert_eq!(string("\"\\\"test 123\\\"\""), Ok(("", Term::string("\"test 123\"".to_string()))));
		assert_eq!(string("\"test\\\\123\""), Ok(("", Term::string("test\\123".to_string()))));
		assert_eq!(string("\"test\\\\123\\\\\""), Ok(("", Term::string("test\\123\\".to_string()))));
		assert_eq!(string("\"\\\\test 123\\\\\""), Ok(("", Term::string("\\test 123\\".to_string()))));
		assert_eq!(string("\"test\\n123\""), Ok(("", Term::string("test\n123".to_string()))));
		assert_eq!(string("\"test\\n123\\n\""), Ok(("", Term::string("test\n123\n".to_string()))));
		assert_eq!(string("\"\\ntest 123\\n\""), Ok(("", Term::string("\ntest 123\n".to_string()))));
		assert_eq!(string("\"test\\t123\""), Ok(("", Term::string("test\t123".to_string()))));
		assert_eq!(string("\"test\\t123\\t\""), Ok(("", Term::string("test\t123\t".to_string()))));
		assert_eq!(string("\"\\ttest 123\\t\""), Ok(("", Term::string("\ttest 123\t".to_string()))));
		assert_eq!(string("\"test 🙂 123\""), Ok(("", Term::string("test 🙂 123".to_string()))));
		assert!(string("\"test 123\"a").is_err());
		assert!(string("\"test\\i123\"").is_err());
	}
}