// Copyright (C) 2017 The Android Open Source Project
//
// 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.gerrit.server.restapi.project;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.gerrit.common.data.GlobalCapability;
import com.google.gerrit.entities.AccessSection;
import com.google.gerrit.entities.AccountGroup;
import com.google.gerrit.entities.GroupDescription;
import com.google.gerrit.entities.GroupReference;
import com.google.gerrit.entities.LabelType;
import com.google.gerrit.entities.Permission;
import com.google.gerrit.entities.PermissionRule;
import com.google.gerrit.entities.Project;
import com.google.gerrit.exceptions.InvalidNameException;
import com.google.gerrit.extensions.api.access.AccessSectionInfo;
import com.google.gerrit.extensions.api.access.PermissionInfo;
import com.google.gerrit.extensions.api.access.PermissionRuleInfo;
import com.google.gerrit.extensions.restapi.AuthException;
import com.google.gerrit.extensions.restapi.BadRequestException;
import com.google.gerrit.extensions.restapi.ResourceConflictException;
import com.google.gerrit.extensions.restapi.UnprocessableEntityException;
import com.google.gerrit.server.IdentifiedUser;
import com.google.gerrit.server.config.AllProjectsName;
import com.google.gerrit.server.group.GroupResolver;
import com.google.gerrit.server.permissions.PermissionBackendException;
import com.google.gerrit.server.permissions.PluginPermissionsUtil;
import com.google.gerrit.server.project.ProjectConfig;
import com.google.gerrit.server.project.RefPattern;
import com.google.inject.Inject;
import com.google.inject.Provider;
import com.google.inject.Singleton;
import java.util.List;
import java.util.Map;
import java.util.Set;

@Singleton
public class SetAccessUtil {
  private final GroupResolver groupResolver;
  private final AllProjectsName allProjects;
  private final Provider<SetParent> setParent;
  private final PluginPermissionsUtil pluginPermissionsUtil;

  @Inject
  private SetAccessUtil(
      GroupResolver groupResolver,
      AllProjectsName allProjects,
      Provider<SetParent> setParent,
      PluginPermissionsUtil pluginPermissionsUtil) {
    this.groupResolver = groupResolver;
    this.allProjects = allProjects;
    this.setParent = setParent;
    this.pluginPermissionsUtil = pluginPermissionsUtil;
  }

  ImmutableList<AccessSection> getAccessSections(
      Map<String, AccessSectionInfo> sectionInfos, boolean rejectNonResolvableGroups)
      throws UnprocessableEntityException {
    if (sectionInfos == null) {
      return ImmutableList.of();
    }

    ImmutableList.Builder<AccessSection> sections =
        ImmutableList.builderWithExpectedSize(sectionInfos.size());
    for (Map.Entry<String, AccessSectionInfo> entry : sectionInfos.entrySet()) {
      if (entry.getValue().permissions == null) {
        continue;
      }

      AccessSection.Builder accessSection = AccessSection.builder(entry.getKey());
      for (Map.Entry<String, PermissionInfo> permissionEntry :
          entry.getValue().permissions.entrySet()) {
        if (permissionEntry.getValue().rules == null) {
          continue;
        }

        Permission.Builder p = Permission.builder(permissionEntry.getKey());
        if (permissionEntry.getValue().exclusive != null) {
          p.setExclusiveGroup(permissionEntry.getValue().exclusive);
        }

        for (Map.Entry<String, PermissionRuleInfo> permissionRuleInfoEntry :
            permissionEntry.getValue().rules.entrySet()) {
          GroupDescription.Basic group = groupResolver.parseId(permissionRuleInfoEntry.getKey());
          GroupReference groupReference;
          if (group != null) {
            groupReference = GroupReference.forGroup(group);
          } else {
            if (rejectNonResolvableGroups) {
              throw new UnprocessableEntityException(
                  permissionRuleInfoEntry.getKey() + " is not a valid group ID");
            }
            AccountGroup.UUID uuid = AccountGroup.UUID.parse(permissionRuleInfoEntry.getKey());
            groupReference = GroupReference.create(uuid, uuid.get());
          }

          PermissionRuleInfo pri = permissionRuleInfoEntry.getValue();
          PermissionRule.Builder r = PermissionRule.builder(groupReference);
          if (pri != null) {
            if (pri.max != null) {
              r.setMax(pri.max);
            }
            if (pri.min != null) {
              r.setMin(pri.min);
            }
            if (pri.action != null) {
              r.setAction(GetAccess.ACTION_TYPE.inverse().get(pri.action));
            }
            if (pri.force != null) {
              r.setForce(pri.force);
            }
          }
          p.add(r);
        }
        accessSection.addPermission(p);
      }
      sections.add(accessSection.build());
    }
    return sections.build();
  }

  /**
   * Checks that the removals and additions are logically valid, but doesn't check current user's
   * permission.
   */
  void validateChanges(
      ProjectConfig config, List<AccessSection> removals, List<AccessSection> additions)
      throws BadRequestException, InvalidNameException {
    // Perform permission checks
    for (AccessSection section : Iterables.concat(additions, removals)) {
      boolean isGlobalCapabilities = AccessSection.GLOBAL_CAPABILITIES.equals(section.getName());
      if (isGlobalCapabilities) {
        if (!allProjects.equals(config.getName())) {
          throw new BadRequestException(
              "Cannot edit global capabilities for projects other than " + allProjects.get());
        }
      }
    }

    // Perform addition checks
    for (AccessSection section : additions) {
      String name = section.getName();
      boolean isGlobalCapabilities = AccessSection.GLOBAL_CAPABILITIES.equals(name);

      if (!isGlobalCapabilities) {
        if (!AccessSection.isValidRefSectionName(name)) {
          throw new BadRequestException("invalid section name");
        }
        RefPattern.validate(name);

        // Check all permissions for soundness
        for (Permission p : section.getPermissions()) {
          if (!isPermission(p.getName())) {
            throw new BadRequestException("Unknown permission: " + p.getName());
          }
        }
      } else {
        // Check all permissions for soundness
        for (Permission p : section.getPermissions()) {
          if (!isCapability(p.getName())) {
            throw new BadRequestException("Unknown global capability: " + p.getName());
          }
        }
      }
    }
  }

  void applyChanges(
      ProjectConfig config, List<AccessSection> removals, List<AccessSection> additions) {
    // Apply removals
    for (AccessSection section : removals) {
      if (section.getPermissions().isEmpty()) {
        // Remove entire section
        config.remove(config.getAccessSection(section.getName()));
        continue;
      }

      // Remove specific permissions
      for (Permission p : section.getPermissions()) {
        if (p.getRules().isEmpty()) {
          config.remove(config.getAccessSection(section.getName()), p);
        } else {
          for (PermissionRule r : p.getRules()) {
            config.remove(config.getAccessSection(section.getName()), p, r);
          }
        }
      }
    }

    // Apply additions
    for (AccessSection section : additions) {
      config.upsertAccessSection(
          section.getName(),
          existingAccessSection -> {
            for (Permission p : section.getPermissions()) {
              Permission currentPermission =
                  existingAccessSection.build().getPermission(p.getName());
              if (currentPermission == null) {
                // Add Permission
                existingAccessSection.addPermission(p.toBuilder());
              } else {
                for (PermissionRule r : p.getRules()) {
                  // AddPermissionRule
                  existingAccessSection.upsertPermission(p.getName()).add(r.toBuilder());
                }
              }
            }
          });
    }
  }

  /**
   * Updates the parent project in the given config.
   *
   * @param identifiedUser the user
   * @param config the config to modify
   * @param projectName the project for which to change access.
   * @param newParentProjectName the new parent to set; passing null will make this a nop
   * @param checkAdmin if set, verify that user has administrateServer permission
   */
  public void setParentName(
      IdentifiedUser identifiedUser,
      ProjectConfig config,
      Project.NameKey projectName,
      Project.NameKey newParentProjectName,
      boolean checkAdmin)
      throws ResourceConflictException, AuthException, PermissionBackendException,
          BadRequestException {
    if (newParentProjectName != null
        && !config.getProject().getNameKey().equals(allProjects)
        && !config.getProject().getParent(allProjects).equals(newParentProjectName)) {
      try {
        setParent
            .get()
            .validateParentUpdate(
                projectName, identifiedUser, newParentProjectName.get(), checkAdmin);
      } catch (UnprocessableEntityException e) {
        throw new ResourceConflictException(e.getMessage(), e);
      }
      config.updateProject(p -> p.setParent(newParentProjectName));
    }
  }

  private boolean isPermission(String name) {
    if (Permission.isPermission(name)) {
      if (Permission.isLabel(name) || Permission.isLabelAs(name)) {
        String labelName = Permission.extractLabel(name);
        try {
          LabelType.checkName(labelName);
        } catch (IllegalArgumentException e) {
          return false;
        }
      }
      return true;
    }
    Set<String> pluginPermissions =
        pluginPermissionsUtil.collectPluginProjectPermissions().keySet();
    return pluginPermissions.contains(name);
  }

  private boolean isCapability(String name) {
    if (GlobalCapability.isGlobalCapability(name)) {
      return true;
    }
    Set<String> pluginCapabilities = pluginPermissionsUtil.collectPluginCapabilities().keySet();
    return pluginCapabilities.contains(name);
  }
}