/*
 * Copyright 2016 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.idea.blaze.base.sync.projectview;

import com.google.common.collect.Sets;
import com.google.idea.blaze.base.model.primitives.LanguageClass;
import com.google.idea.blaze.base.model.primitives.WorkspaceType;
import com.google.idea.blaze.base.projectview.ProjectViewSet;
import com.google.idea.blaze.base.projectview.section.sections.AdditionalLanguagesSection;
import com.google.idea.blaze.base.projectview.section.sections.WorkspaceTypeSection;
import com.google.idea.blaze.base.scope.BlazeContext;
import com.google.idea.blaze.base.scope.output.IssueOutput;
import com.google.idea.blaze.base.sync.BlazeSyncPlugin;
import com.intellij.openapi.diagnostic.Logger;
import java.util.EnumSet;
import java.util.Set;

/** Reads the user's language preferences from the project view. */
public class LanguageSupport {

  private static final Logger logger = Logger.getInstance(LanguageSupport.class);

  public static WorkspaceLanguageSettings createWorkspaceLanguageSettings(
      BlazeContext context, ProjectViewSet projectViewSet) {
    WorkspaceType workspaceType = projectViewSet.getScalarValue(WorkspaceTypeSection.KEY);
    Set<WorkspaceType> supportedTypes = supportedWorkspaceTypes();
    if (workspaceType != null && !supportedTypes.contains(workspaceType)) {
      IssueOutput.error(
              String.format(
                  "Workspace type '%s' is not supported by this plugin", workspaceType.getName()))
          .submit(context);
      return null;
    }
    if (workspaceType == null) {
      // if no workspace type is specified, prioritize by enum ordinal.
      for (BlazeSyncPlugin syncPlugin : BlazeSyncPlugin.EP_NAME.getExtensions()) {
        WorkspaceType recommendedType = syncPlugin.getDefaultWorkspaceType();
        if (recommendedType != null
            && (workspaceType == null || workspaceType.ordinal() > recommendedType.ordinal())) {
          workspaceType = recommendedType;
        }
      }
    }

    if (workspaceType == null) {
      logger.error("Could not find workspace type."); // Should never happen
      return null;
    }

    Set<LanguageClass> activeLanguages = Sets.newHashSet(workspaceType.getLanguages());
    activeLanguages.addAll(projectViewSet.listItems(AdditionalLanguagesSection.KEY));

    Set<LanguageClass> supportedLanguages = supportedLanguagesForWorkspaceType(workspaceType);
    Set<LanguageClass> availableLanguages = EnumSet.noneOf(LanguageClass.class);
    for (WorkspaceType type : supportedTypes) {
      availableLanguages.addAll(supportedLanguagesForWorkspaceType(type));
    }

    for (LanguageClass languageClass : activeLanguages) {
      if (!availableLanguages.contains(languageClass)) {
        IssueOutput.error(
                String.format(
                    "Language '%s' is not supported by this plugin", languageClass.getName()))
            .submit(context);
        return null;
      }
      if (!supportedLanguages.contains(languageClass)) {
        IssueOutput.error(
                String.format(
                    "Language '%s' is not supported for this plugin with workspace type: '%s'",
                    languageClass.getName(), workspaceType.getName()))
            .submit(context);
        return null;
      }
    }

    activeLanguages.add(LanguageClass.GENERIC);
    return new WorkspaceLanguageSettings(workspaceType, activeLanguages);
  }

  /** The {@link WorkspaceType}s supported by this plugin */
  private static Set<WorkspaceType> supportedWorkspaceTypes() {
    Set<WorkspaceType> supportedTypes = EnumSet.noneOf(WorkspaceType.class);
    for (BlazeSyncPlugin syncPlugin : BlazeSyncPlugin.EP_NAME.getExtensions()) {
      supportedTypes.addAll(syncPlugin.getSupportedWorkspaceTypes());
    }
    return supportedTypes;
  }

  /** @return The set of {@link LanguageClass}'s supported for this {@link WorkspaceType}s. */
  public static Set<LanguageClass> supportedLanguagesForWorkspaceType(WorkspaceType type) {
    Set<LanguageClass> supportedLanguages = EnumSet.noneOf(LanguageClass.class);
    for (BlazeSyncPlugin syncPlugin : BlazeSyncPlugin.EP_NAME.getExtensions()) {
      supportedLanguages.addAll(syncPlugin.getSupportedLanguagesInWorkspace(type));
    }
    return supportedLanguages;
  }
}