/*
 * Copyright 2008 The Closure Compiler Authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.javascript.jscomp;

import com.google.common.collect.Lists;
import com.google.common.collect.Sets;
import com.google.javascript.jscomp.NodeTraversal.Callback;
import com.google.javascript.jscomp.NodeTraversal.ScopedCallback;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.Token;

import junit.framework.TestCase;

import java.util.Collection;
import java.util.List;
import java.util.Set;

/**
 */
public class CombinedCompilerPassTest extends TestCase  {

  private Compiler compiler;

  /**
   * Returns a Node tree with the post-order traversal a b c d e f g h i j k l m
   * and the in-order traversal m d a b c h e f g l i j k:
   *
   *                                   m
   *                         ,---------|---------.
   *                         d         h         l
   *                      ,--|--.   ,--|--.   ,--|--.
   *                      a  b  c   e  f  g   i  j  k
   *
   */
  private static Node createPostOrderAlphabet() {
    Node a = Node.newString("a");
    Node b = Node.newString("b");
    Node c = Node.newString("c");
    Node d = Node.newString("d");
    Node e = Node.newString("e");
    Node f = Node.newString("f");
    Node g = Node.newString("g");
    Node h = Node.newString("h");
    Node i = Node.newString("i");
    Node j = Node.newString("j");
    Node k = Node.newString("k");
    Node l = Node.newString("l");
    Node m = Node.newString("m");

    d.addChildToBack(a);
    d.addChildToBack(b);
    d.addChildToBack(c);

    h.addChildrenToBack(e);
    h.addChildrenToBack(f);
    h.addChildrenToBack(g);

    l.addChildToBack(i);
    l.addChildToBack(j);
    l.addChildToBack(k);

    m.addChildToBack(d);
    m.addChildToBack(h);
    m.addChildToBack(l);

    return m;
  }

  @Override
  public void setUp() throws Exception {
    super.setUp();
    compiler = new Compiler();
  }

  /**
   * Concatenates contents of string nodes encountered in pre-order
   * and post-order traversals. Abbreviates traversals by ignoring subtrees
   * rooted with specified strings.
   */
  private static class ConcatTraversal implements Callback {
    private StringBuilder visited = new StringBuilder();
    private StringBuilder shouldTraversed = new StringBuilder();
    private Set<String> ignoring = Sets.newHashSet();

    ConcatTraversal ignore(String s) {
      ignoring.add(s);
      return this;
    }

    @Override
    public void visit(NodeTraversal t, Node n, Node parent) {
      assertEquals(Token.STRING, n.getType());
      visited.append(n.getString());
    }

    @Override
    public boolean shouldTraverse(NodeTraversal t, Node n, Node parent) {
      assertEquals(Token.STRING, n.getType());
      shouldTraversed.append(n.getString());
      return !ignoring.contains(n.getString());
    }

    /** Returns strings concatenated during post-order traversal. */
    String getVisited() {
      return visited.toString();
    }

    /** Returns strings concatenated during pre-order traversal. */
    String getShouldTraversed() {
      return shouldTraversed.toString();
    }

    Collection<String> getIgnoring() {
      return ignoring;
    }
  }

  /**
   * Collection of data for a traversal test. Contains the traversal callback
   * and the expected pre- and post-order traversal results.
   */
  private static class TestHelper {
    private ConcatTraversal traversal;
    private String expectedVisited;
    private String shouldTraverseExpected;

    TestHelper(ConcatTraversal traversal, String expectedVisited,
         String shouldTraverseExpected) {
      this.traversal = traversal;
      this.expectedVisited = expectedVisited;
      this.shouldTraverseExpected = shouldTraverseExpected;
    }

    ConcatTraversal getTraversal() {
      return traversal;
    }

    void checkResults() {
      assertEquals("ConcatTraversal ignoring " +
                   traversal.getIgnoring().toString() +
                   " has unexpected visiting order",
                   expectedVisited, traversal.getVisited());

      assertEquals("ConcatTraversal ignoring " +
                   traversal.getIgnoring().toString() +
                   " has unexpected traversal order",
                   shouldTraverseExpected, traversal.getShouldTraversed());
    }
  }

  private static List<TestHelper> createStringTests() {
    List<TestHelper> tests = Lists.newArrayList();

    tests.add(new TestHelper(
        new ConcatTraversal(), "abcdefghijklm", "mdabchefglijk"));

    tests.add(new TestHelper(
        new ConcatTraversal().ignore("d"), "efghijklm", "mdhefglijk"));

    tests.add(new TestHelper(
        new ConcatTraversal().ignore("f"), "abcdeghijklm", "mdabchefglijk"));

    tests.add(new TestHelper(new ConcatTraversal().ignore("m"), "", "m"));

    return tests;
  }

  public void testIndividualPasses() {
    for (TestHelper test : createStringTests()) {
      CombinedCompilerPass pass =
          new CombinedCompilerPass(compiler, test.getTraversal());
      pass.process(null, createPostOrderAlphabet());
      test.checkResults();
    }
  }

  public void testCombinedPasses() {
    List<TestHelper> tests  = createStringTests();
    Callback[] callbacks = new Callback[tests.size()];
    int i = 0;
    for (TestHelper test : tests) {
      callbacks[i++] = test.getTraversal();
    }
    CombinedCompilerPass pass =
        new CombinedCompilerPass(compiler, callbacks);
    pass.process(null, createPostOrderAlphabet());
    for (TestHelper test : tests) {
      test.checkResults();
    }
  }

  /**
   * Records the scopes visited during an AST traversal. Abbreviates traversals
   * by ignoring subtrees rooted with specified NAME nodes.
   */
  private static class ScopeRecordingCallback implements ScopedCallback {

    Set<Node> visitedScopes = Sets.newHashSet();
    Set<String> ignoring = Sets.newHashSet();

    void ignore(String name) {
      ignoring.add(name);
    }

    @Override
    public void enterScope(NodeTraversal t) {
      visitedScopes.add(t.getScopeRoot());
    }

    @Override
    public boolean shouldTraverse(NodeTraversal t, Node n, Node parent) {
      return !n.isName() || !ignoring.contains(n.getString());
    }

    Set<Node> getVisitedScopes() {
      return visitedScopes;
    }

    @Override
    public void exitScope(NodeTraversal t) {
    }

    @Override
    public void visit(NodeTraversal t, Node n, Node parent) {
    }

  }

  public void testScopes() {
    Node root =
        compiler.parseTestCode("var y = function() { var x = function() { };}");

    ScopeRecordingCallback c1 = new ScopeRecordingCallback();
    c1.ignore("y");
    ScopeRecordingCallback c2 = new ScopeRecordingCallback();
    c2.ignore("x");
    ScopeRecordingCallback c3 = new ScopeRecordingCallback();

    CombinedCompilerPass pass = new CombinedCompilerPass(compiler, c1, c2, c3);
    pass.process(null, root);

    assertEquals(1, c1.getVisitedScopes().size());
    assertEquals(2, c2.getVisitedScopes().size());
    assertEquals(3, c3.getVisitedScopes().size());
  }
}