use std::fmt;
use crate::PList;
use super::Located;

/**
 * Symbol.
 */
#[derive(Clone, Debug)]
pub struct Symbol {
	pub id: String
}

impl Symbol {
	pub fn format<T: fmt::Display>(t: T) -> Symbol {
		Symbol {
			id: format!("{}", t)
		}
	}
}

impl PartialEq<str> for Symbol {
	fn eq(&self, other: &str) -> bool {
		self.id == other
	}
}

impl PartialEq<String> for Symbol {
	fn eq(&self, other: &String) -> bool {
		self.id == *other
	}
}

impl fmt::Display for Symbol {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		write!(f, "{}", self.id)
	}
}

/**
 * Identifiers index.
 *
 * <index> ::= <numeral> | <symbol>
 */
#[derive(Clone, Debug)]
pub enum Index {
	Numeral(i64),
	Symbol(Symbol)
}

impl fmt::Display for Index {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		use Index::*;
		match self {
			Numeral(i) => write!(f, "{}", i),
			Symbol(s) => write!(f, "{}", s)
		}
	}
}

/**
 * Identifiers.
 *
 * <identifier> ::= <symbol> | ( _ <symbol> <index>+ )
 */
#[derive(Clone, Debug)]
pub struct Ident {
	pub id: Located<Symbol>,
	pub indexes: Vec<Located<Index>>
}

impl From<Located<Symbol>> for Located<Ident> {
	fn from(sym: Located<Symbol>) -> Self {
		let span = sym.span();
		Located::new(Ident {
			id: sym,
			indexes: Vec::new()
		}, span)
	}
}

impl fmt::Display for Ident {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		if self.indexes.is_empty() {
			self.id.fmt(f)
		} else {
			write!(f, "(_ {} {})", self.id, PList(&self.indexes))
		}
	}
}

#[derive(Clone)]
pub struct Keyword {
	pub id: String
}

impl fmt::Display for Keyword {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		self.id.fmt(f)
	}
}

/**
 * <attribute> ::= <keyword> | <keyword> <attribute_value>
 */
#[derive(Clone)]
pub struct Attribute {
	pub key: Located<Keyword>,
	pub value: Option<Located<AttributeValue>>
}

impl fmt::Display for Attribute {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		match &self.value {
			Some(value) => {
				write!(f, "{} {}", self.key, value)
			},
			None => self.key.fmt(f)
		}
	}
}

/**
 * <attribute_value> ::= <spec_const> | <symbol> | <s_expr*>
 */
#[derive(Clone)]
pub enum AttributeValue {
	// Const(Constant),
	Sym(Located<Symbol>),
	List(Vec<Located<SExpr>>)
}

impl fmt::Display for AttributeValue {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		use AttributeValue::*;
		match self {
			// Const(c) => c.fmt(f),
			Sym(s) => s.fmt(f),
			List(exprs) => PList(&exprs).fmt(f)
		}
	}
}

/**
 * <s_expr> ::= <spec_const> | <symbol> | <keyword> | <s_expr*>
 */
#[derive(Clone)]
pub enum SExpr {
	// Const(Constant),
	Sym(Located<Symbol>),
	Keyword(Located<Keyword>),
	List(Vec<Located<SExpr>>)
}

impl fmt::Display for SExpr {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		use SExpr::*;
		match self {
			// Const(c) => c.fmt(f),
			Sym(s) => s.fmt(f),
			Keyword(k) => k.fmt(f),
			List(l) => PList(l).fmt(f)
		}
	}
}

/**
 * <sort> ::= <identifier> | (<identifier> <sort>+)
 */
#[derive(Clone)]
pub struct Sort {
	pub id: Located<Ident>,
	pub parameters: Vec<Located<Sort>>
}

impl fmt::Display for Sort {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		if self.parameters.is_empty() {
			self.id.fmt(f)
		} else {
			write!(f, "({} {})", self.id, PList(&self.parameters))
		}
	}
}

/**
 * <term>   ::= <spec_const>
 *			| ( let ( <var_binding>+ ) <term> )
 *			| ( forall ( <sorted_var>+ ) <term> )
 *			| ( exists ( <sorted_var>+ ) <term> )
 */
#[derive(Clone)]
pub enum Term {
	// Const(Constant),
	Ident(Located<Ident>),
	Let {
		bindings: Vec<Located<Binding>>,
		body: Box<Located<Term>>
	},
	Forall {
		vars: Vec<Located<SortedVar>>,
		body: Box<Located<Term>>
	},
	Exists {
		vars: Vec<Located<SortedVar>>,
		body: Box<Located<Term>>
	},
	Match {
		term: Box<Located<Term>>,
		cases: Vec<Located<MatchCase>>
	},
	Apply {
		id: Located<Ident>,
		args: Box<Vec<Located<Term>>>
	},
	Coerce {
		term: Box<Located<Term>>,
		sort: Located<Sort>
	}
}

impl fmt::Display for Term {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		use Term::*;
		match self {
			// Const(c) => c.fmt(f),
			Ident(id) => id.fmt(f),
			Let { bindings, body } => write!(f, "(let ({}) {})", PList(&bindings), body),
			Forall { vars, body } => write!(f, "(forall ({}) {})", PList(&vars), body),
			Exists { vars, body } => write!(f, "(exists ({}) {})", PList(&vars), body),
			Match { term, cases } => write!(f, "(match {}, ({}))", term, PList(cases)),
			Apply { id, args } => write!(f, "({} {})", id, PList(&args)),
			Coerce { term, sort } => write!(f, "(as {} {})", term, sort)
		}
	}
}

#[derive(Clone)]
pub struct MatchCase {
	pub pattern: Located<Pattern>,
	pub term: Box<Located<Term>>
}

impl fmt::Display for MatchCase {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
		write!(f, "({} {})", self.pattern, self.term)
	}
}

#[derive(Clone)]
pub struct Pattern {
	pub id: Located<Symbol>,
	pub args: Vec<Located<Symbol>>
}

impl fmt::Display for Pattern {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
		if self.args.is_empty() {
			write!(f, "{}", self.id)
		} else {
			write!(f, "({} {})", self.id, PList(&self.args))
		}
	}
}

/**
 * <var_binding> ::= ( <symbol> <term> )
 */
#[derive(Clone)]
pub struct Binding {
	pub id: Located<Symbol>,
	pub value: Box<Located<Term>>
}

impl fmt::Display for Binding {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		write!(f, "({} {})", self.id, self.value)
	}
}

/**
 * <sorted_var> ::= ( <symbol> <sort> )
 */
#[derive(Clone)]
pub struct SortedVar {
	pub id: Located<Symbol>,
	pub sort: Located<Sort>
}

impl fmt::Display for SortedVar {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		write!(f, "({} {})", self.id, self.sort)
	}
}

/**
 * <datatype_dec> ::= ( <constructor_dec>+ )
 *				  | ( par ( <symbol>+ ) <constructor_dec>+ )
 */
#[derive(Clone)]
pub struct DataTypeDeclaration {
	pub parameters: Vec<Located<Symbol>>,
	pub constructors: Vec<Located<ConstructorDeclaration>>
}

impl fmt::Display for DataTypeDeclaration {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		write!(f, "({})", PList(&self.constructors))
	}
}

/**
 * <constructor_dec> ::= ( <symbol> <selector_dec>* )
 */
#[derive(Clone)]
pub struct ConstructorDeclaration {
	pub id: Located<Symbol>,
	pub selectors: Vec<Located<SelectorDeclaration>>
}

impl fmt::Display for ConstructorDeclaration {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		write!(f, "({} {})", self.id, PList(&self.selectors))
	}
}

/**
 * <selector_dec> ::= ( <symbol> <sort> )
 */
#[derive(Clone)]
pub struct SelectorDeclaration {
	pub id: Located<Symbol>,
	pub sort: Located<Sort>
}

impl fmt::Display for SelectorDeclaration {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		write!(f, "({} {})", self.id, self.sort)
	}
}

/**
 * <sort_dec> ::= ( <symbol> <numeral> )
 */
#[derive(Clone)]
pub struct SortDeclaration {
	pub id: Located<Symbol>,
	pub arity: Located<i64>
}

impl fmt::Display for SortDeclaration {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		write!(f, "({} {})", self.id, self.arity)
	}
}

/**
 * <command>	::= ( assert <term> )
 *				| ( check-sat )
 *				| ( declare-const <symbol> <sort> )
 *				| ( declare-datatype <symbol> <datatype_decl> )
 *				| ( declare-datatypes ( <sort_dec>n+1 ) ( <datatype_dec>n+1 ) )
 *				| ( exit )
 *				| ( set-info <attribute> )
 *				| ( set-logic <symbol> )
 */
#[derive(Clone)]
pub enum Command {
	Assert(Located<Term>),
	CheckSat,
	DeclareConst(Located<Symbol>, Located<Sort>),
	DeclareDatatype(Located<Symbol>, Located<DataTypeDeclaration>),
	DeclareDatatypes(Vec<Located<SortDeclaration>>, Vec<Located<DataTypeDeclaration>>),
	DeclareFun(Located<Symbol>, Vec<Located<Sort>>, Located<Sort>),
	Exit,
	GetModel,
	SetInfo(Located<Attribute>),
	SetLogic(Located<Symbol>)
}

impl fmt::Display for Command {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		use Command::*;
		match self {
			Assert(t) => write!(f, "(assert {})", t),
			CheckSat => write!(f, "(check-sat)"),
			DeclareConst(id, sort) => write!(f, "(declare-const {} {})", id, sort),
			DeclareDatatype(id, decl) => write!(f, "(declare-datatype {} {})", id, decl),
			DeclareDatatypes(sort_decls, decls) => write!(f, "(declare-datatypes ({}) ({}))", PList(&sort_decls), PList(&decls)),
			DeclareFun(id, args, result) => write!(f, "(declare-fun {} ({}) {})", id, PList(args), result),
			Exit => write!(f, "(exit)"),
			GetModel => write!(f, "(get-model)"),
			SetInfo(a) => write!(f, "(set-info {})", a),
			SetLogic(l) => write!(f, "(set-logic {})", l)
		}
	}
}