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/*
 * Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
 * Use of this file is governed by the BSD 3-clause license that
 * can be found in the LICENSE.txt file in the project root.
 */

package org.antlr.v4.automata;

import org.antlr.v4.runtime.atn.ATN;
import org.antlr.v4.runtime.atn.ATNState;
import org.antlr.v4.tool.ast.ActionAST;
import org.antlr.v4.tool.ast.BlockAST;
import org.antlr.v4.tool.ast.GrammarAST;
import org.antlr.v4.tool.ast.PredAST;
import org.antlr.v4.tool.ast.TerminalAST;

import java.util.List;

public interface ATNFactory {
	/** A pair of states pointing to the left/right (start and end) states of a
	 *  state submachine.  Used to build ATNs.
	 */
	public static class Handle {
		public ATNState left;
		public ATNState right;

		public Handle(ATNState left, ATNState right) {
			this.left = left;
			this.right = right;
		}

		@Override
		public String toString() {
			return "("+left+","+right+")";
		}
	}


	ATN createATN();

	void setCurrentRuleName(String name);

	void setCurrentOuterAlt(int alt);


	Handle rule(GrammarAST ruleAST, String name, Handle blk);


	ATNState newState();


	Handle label(Handle t);


	Handle listLabel(Handle t);


	Handle tokenRef(TerminalAST node);


	Handle set(GrammarAST associatedAST, List alts, boolean invert);


	Handle charSetLiteral(GrammarAST charSetAST);


	Handle range(GrammarAST a, GrammarAST b);

	/** For a non-lexer, just build a simple token reference atom.
	 *  For a lexer, a string is a sequence of char to match.  That is,
	 *  "fog" is treated as 'f' 'o' 'g' not as a single transition in
	 *  the DFA.  Machine== o-'f'->o-'o'->o-'g'->o and has n+1 states
	 *  for n characters.
	 */

	Handle stringLiteral(TerminalAST stringLiteralAST);

	/** For reference to rule r, build
	 *
	 *  o-e->(r)  o
	 *
	 *  where (r) is the start of rule r and the trailing o is not linked
	 *  to from rule ref state directly (it's done thru the transition(0)
	 *  RuleClosureTransition.
	 *
	 *  If the rule r is just a list of tokens, it's block will be just
	 *  a set on an edge o->o->o-set->o->o->o, could inline it rather than doing
	 *  the rule reference, but i'm not doing this yet as I'm not sure
	 *  it would help much in the ATN->DFA construction.
	 *
	 *  TODO add to codegen: collapse alt blks that are sets into single matchSet
	 * @param node
	 */

	Handle ruleRef(GrammarAST node);

	/** From an empty alternative build Grip o-e->o */

	Handle epsilon(GrammarAST node);

	/** Build what amounts to an epsilon transition with a semantic
	 *  predicate action.  The pred is a pointer into the AST of
	 *  the SEMPRED token.
	 */

	Handle sempred(PredAST pred);

	/** Build what amounts to an epsilon transition with an action.
	 *  The action goes into ATN though it is ignored during analysis.
	 */

	Handle action(ActionAST action);


	Handle action(String action);


	Handle alt(List els);

	/** From A|B|..|Z alternative block build
     *
     *  o->o-A->o->o (last ATNState is blockEndATNState pointed to by all alts)
     *  |          ^
     *  o->o-B->o--|
     *  |          |
     *  ...        |
     *  |          |
     *  o->o-Z->o--|
     *
     *  So every alternative gets begin ATNState connected by epsilon
     *  and every alt right side points at a block end ATNState.  There is a
     *  new ATNState in the ATNState in the Grip for each alt plus one for the
     *  end ATNState.
     *
     *  Special case: only one alternative: don't make a block with alt
     *  begin/end.
     *
     *  Special case: if just a list of tokens/chars/sets, then collapse
     *  to a single edge'd o-set->o graph.
     *
     *  Set alt number (1..n) in the left-Transition ATNState.
     */

	Handle block(BlockAST blockAST, GrammarAST ebnfRoot, List alternativeGrips);

//	Handle notBlock(GrammarAST blockAST, Handle set);

	/** From (A)? build either:
	 *
	 *  o--A->o
	 *  |     ^
	 *  o---->|
	 *
	 *  or, if A is a block, just add an empty alt to the end of the block
	 */

	Handle optional(GrammarAST optAST, Handle blk);

	/** From (A)+ build
	 *
	 *     |---|    (Transition 2 from A.right points at alt 1)
	 *     v   |    (follow of loop is Transition 1)
	 *  o->o-A-o->o
	 *
	 *  Meaning that the last ATNState in A points back to A's left Transition ATNState
	 *  and we add a new begin/end ATNState.  A can be single alternative or
	 *  multiple.
	 *
	 *  During analysis we'll call the follow link (transition 1) alt n+1 for
	 *  an n-alt A block.
	 */

	Handle plus(GrammarAST plusAST, Handle blk);

	/** From (A)* build
	 *
	 *     |---|
	 *     v   |
	 *  o->o-A-o--o (Transition 2 from block end points at alt 1; follow is Transition 1)
	 *  |         ^
	 *  o---------| (optional branch is 2nd alt of optional block containing A+)
	 *
	 *  Meaning that the last (end) ATNState in A points back to A's
	 *  left side ATNState and we add 3 new ATNStates (the
	 *  optional branch is built just like an optional subrule).
	 *  See the Aplus() method for more on the loop back Transition.
	 *  The new node on right edge is set to RIGHT_EDGE_OF_CLOSURE so we
	 *  can detect nested (A*)* loops and insert an extra node.  Previously,
	 *  two blocks shared same EOB node.
	 *
	 *  There are 2 or 3 decision points in a A*.  If A is not a block (i.e.,
	 *  it only has one alt), then there are two decisions: the optional bypass
	 *  and then loopback.  If A is a block of alts, then there are three
	 *  decisions: bypass, loopback, and A's decision point.
	 *
	 *  Note that the optional bypass must be outside the loop as (A|B)* is
	 *  not the same thing as (A|B|)+.
	 *
	 *  This is an accurate ATN representation of the meaning of (A)*, but
	 *  for generating code, I don't need a DFA for the optional branch by
	 *  virtue of how I generate code.  The exit-loopback-branch decision
	 *  is sufficient to let me make an appropriate enter, exit, loop
	 *  determination.  See codegen.g
	 */

	Handle star(GrammarAST starAST, Handle blk);

	/** Build an atom with all possible values in its label */

	Handle wildcard(GrammarAST associatedAST);


	Handle lexerAltCommands(Handle alt, Handle cmds);


	Handle lexerCallCommand(GrammarAST ID, GrammarAST arg);


	Handle lexerCommand(GrammarAST ID);
}