// Copyright 2019 The Bazel Authors. All rights reserved.
//
// 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.devtools.build.lib.bazel.rules.ninja.parser;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableSortedMap;
import com.google.devtools.build.lib.collect.ImmutableSortedKeyListMultimap;
import com.google.devtools.build.lib.vfs.PathFragment;
import com.google.errorprone.annotations.Immutable;
import java.util.Collection;
import java.util.List;
import java.util.Objects;
import java.util.stream.Collectors;

/** Ninja target (build statement) representation. */
public final class NinjaTarget {
  /** Builder for {@link NinjaTarget}. */
  public static class Builder {
    private String ruleName;
    private final ImmutableSortedKeyListMultimap.Builder<InputKind, PathFragment> inputsBuilder;
    private final ImmutableSortedKeyListMultimap.Builder<OutputKind, PathFragment> outputsBuilder;
    private final NinjaScope scope;
    private final int offset;

    private final ImmutableSortedMap.Builder<String, String> variablesBuilder;

    private Builder(NinjaScope scope, int offset) {
      this.scope = scope;
      this.offset = offset;
      inputsBuilder = ImmutableSortedKeyListMultimap.builder();
      outputsBuilder = ImmutableSortedKeyListMultimap.builder();
      variablesBuilder = ImmutableSortedMap.naturalOrder();
    }

    public Builder setRuleName(String ruleName) {
      this.ruleName = ruleName;
      return this;
    }

    public Builder addInputs(InputKind kind, Collection<PathFragment> inputs) {
      inputsBuilder.putAll(kind, inputs);
      return this;
    }

    public Builder addOutputs(OutputKind kind, Collection<PathFragment> outputs) {
      outputsBuilder.putAll(kind, outputs);
      return this;
    }

    public Builder addVariable(String key, String value) {
      variablesBuilder.put(key, value);
      return this;
    }

    public NinjaTarget build() {
      Preconditions.checkNotNull(ruleName);
      return new NinjaTarget(
          ruleName,
          inputsBuilder.build(),
          outputsBuilder.build(),
          variablesBuilder.build(),
          scope,
          offset);
    }
  }

  /** Enum with possible kinds of inputs. */
  @Immutable
  public enum InputKind implements InputOutputKind {
    USUAL,
    IMPLICIT,
    ORDER_ONLY
  }

  /** Enum with possible kinds of outputs. */
  @Immutable
  public enum OutputKind implements InputOutputKind {
    USUAL,
    IMPLICIT
  }

  /**
   * Marker interface, so that it is possible to address {@link InputKind} and {@link OutputKind}
   * together in one map.
   */
  @Immutable
  public interface InputOutputKind {}

  private final String ruleName;
  private final ImmutableSortedKeyListMultimap<InputKind, PathFragment> inputs;
  private final ImmutableSortedKeyListMultimap<OutputKind, PathFragment> outputs;
  private final ImmutableSortedMap<String, String> variables;
  private final NinjaScope scope;
  private final int offset;

  public NinjaTarget(
      String ruleName,
      ImmutableSortedKeyListMultimap<InputKind, PathFragment> inputs,
      ImmutableSortedKeyListMultimap<OutputKind, PathFragment> outputs,
      ImmutableSortedMap<String, String> variables,
      NinjaScope scope,
      int offset) {
    this.ruleName = ruleName;
    this.inputs = inputs;
    this.outputs = outputs;
    this.variables = variables;
    this.scope = scope;
    this.offset = offset;
  }

  public String getRuleName() {
    return ruleName;
  }

  public ImmutableSortedMap<String, String> getVariables() {
    return variables;
  }

  public boolean hasInputs() {
    return !inputs.isEmpty();
  }

  public List<PathFragment> getOutputs() {
    return outputs.get(OutputKind.USUAL);
  }

  public List<PathFragment> getImplicitOutputs() {
    return outputs.get(OutputKind.IMPLICIT);
  }

  public Collection<PathFragment> getAllOutputs() {
    return outputs.values();
  }

  public Collection<PathFragment> getAllInputs() {
    return inputs.values();
  }

  public Collection<PathFragment> getUsualInputs() {
    return inputs.get(InputKind.USUAL);
  }

  public Collection<PathFragment> getImplicitInputs() {
    return inputs.get(InputKind.IMPLICIT);
  }

  public Collection<PathFragment> getOrderOnlyInputs() {
    return inputs.get(InputKind.ORDER_ONLY);
  }

  public NinjaScope getScope() {
    return scope;
  }

  public int getOffset() {
    return offset;
  }

  public static Builder builder(NinjaScope scope, int offset) {
    return new Builder(scope, offset);
  }

  public String prettyPrint() {
    return "build "
        + prettyPrintPaths("\n", getOutputs())
        + prettyPrintPaths("\n| ", getImplicitOutputs())
        + "\n: "
        + this.ruleName
        + prettyPrintPaths("\n", getUsualInputs())
        + prettyPrintPaths("\n| ", getImplicitInputs())
        + prettyPrintPaths("\n|| ", getOrderOnlyInputs());
  }

  @Override
  public boolean equals(Object o) {
    if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    NinjaTarget that = (NinjaTarget) o;
    // Note: NinjaScope is compared with default Object#equals; it is enough
    // because we do not do any copies of NinjaScope.
    return offset == that.offset && scope.equals(that.scope);
  }

  @Override
  public int hashCode() {
    return Objects.hash(scope, offset);
  }

  private static String prettyPrintPaths(String startDelimiter, Collection<PathFragment> paths) {
    if (paths.isEmpty()) {
      return "";
    }
    return startDelimiter
        + paths.stream().map(PathFragment::getPathString).collect(Collectors.joining("$\n"));
  }
}