use std::rc::Rc;
use std::str::FromStr;
use lalrpop_util::ParseError;
use crate::rsprocess::structure::{RSset, RSprocess, RSenvironment, RSassert, RSassertOp, RSBHML};

grammar;

// matches words (letter followed by numbers, letters or _)
Literal = { r"[[:alpha:]][[:word:]]*" };

// all numbers are i64
Num: i64 = {
    r"[0-9]+" =>? i64::from_str(<>)
	.map_err(|_| ParseError::User { error: "Number is too big" })
};

// macro for matching sequence of patterns with C as separator
Separeted<T, C>: Vec<T> = {
    <mut v:(<T> C)+> <e:T?> => match e {
	None => v,
	Some(e) => {
	    v.push(e);
	    v
	}
    }
};

// ----- SetParser -----
pub Set: RSset<'input> = {
    <s: Set_of_entities> => s
};

Set_of_entities: RSset<'input> = {
    "{" "}" => RSset::from(vec![]),
    "{" <t: Literal> "}" => RSset::from(vec![t]),
    "{" <t: Separeted<Literal, ",">> "}" => RSset::from(t)
};

// ----- ContextParser -----
pub Context: Box<RSprocess<'input>> = {
    "[" "]" => Box::new(RSprocess::Nill),
    "[" <t: CTX_process>  "]" => Box::new(t),
    "[" <t: Separeted<Boxed_CTX_process, ",">> "]" =>
	Box::new(RSprocess::NondeterministicChoice{ children: t })
};

Boxed_CTX_process: Rc<RSprocess<'input>> = {
    <t: CTX_process> => Rc::new(t)
}

CTX_process: RSprocess<'input> = {
    <c: Set_of_entities> "." <k: CTX_process> =>
	RSprocess::EntitySet{ entities: c, next_process: Rc::new(k) },
    "(" <k: CTX_process>  ")" => k,
    "(" <k: Separeted<CTX_process, "+">> ")" =>
	RSprocess::Summation{ children: k },
    "<" <n: Num> <k1: CTX_process> ">" "." <k: CTX_process> =>
	RSprocess::WaitEntity{ repeat: n,
			       repeated_process: Rc::new(k1),
			       next_process: Rc::new(k)},
    "nil" => RSprocess::Nill,
    <identifier: Literal> =>
	RSprocess::RecursiveIdentifier{ identifier }
};

// ----- EnvironmentParser -----
pub Environment: Box<RSenvironment<'input>> = {
    "[" "]" => Box::new(RSenvironment::new()),
    "[" <t: Separeted<Env_term, ",">> "]" => Box::new(RSenvironment::from(t))
};

Env_term: (&'input str, RSprocess<'input>) = {
    <identifier: Literal> "=" <k: CTX_process> => (identifier, k)
};

// ----- AssertParser -----
pub Assert: Box<RSassert<'input>> = {
    <f: Formula_Assert> => Box::new(f)
};

Formula_Assert: RSassert<'input> = {
    "-" <f: Formula_Assert> => RSassert::Not(Box::new(f)),
    "(" <f1: Formula_Assert> "^" <f2: Formula_Assert> ")" =>
	RSassert::Xor(Box::new(f1), Box::new(f2)),
    "(" <f: Separeted<Formula_Assert, "\\/">> ")" => RSassert::Or(f),
    "(" <f: Separeted<Formula_Assert, "/\\">> ")" => RSassert::And(f),
    <c: Set_of_entities> "inW" => RSassert::Sub(c, RSassertOp::InW),
    <c: Set_of_entities> "inR" => RSassert::Sub(c, RSassertOp::InR),
    <c: Set_of_entities> "inI" => RSassert::Sub(c, RSassertOp::InI),
    <c: Set_of_entities> "inP" => RSassert::Sub(c, RSassertOp::InP),
    "?" "inW" => RSassert::NonEmpty(RSassertOp::InW),
    "?" "inR" => RSassert::NonEmpty(RSassertOp::InR),
    "?" "inI" => RSassert::NonEmpty(RSassertOp::InI),
    "?" "inP" => RSassert::NonEmpty(RSassertOp::InP),
};

// ----- BHMLParser -----
pub BHML: Box<RSBHML<'input>> = {
    <g: Formula_BHML> => Box::new(g)
};

Formula_BHML: RSBHML<'input> = {
    "true" => RSBHML::True,
    "false" => RSBHML::False,
    "(" <g: Separeted<Formula_BHML, "\\/">> ")" => RSBHML::Or(g),
    "(" <g: Separeted<Formula_BHML, "/\\">> ")" => RSBHML::And(g),
    "<" <f: Formula_Assert> ">" <g: Formula_BHML> =>
	RSBHML::Diamond(Box::new(f), Box::new(g)),
    "[" <f: Formula_Assert> "]" <g: Formula_BHML> =>
	RSBHML::Box(Box::new(f), Box::new(g)),
};