/*
 * Copyright 2014-present Facebook, Inc.
 *
 * 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.facebook.buck.halide;

import com.facebook.buck.cli.BuckConfig;
import com.facebook.buck.cxx.CxxPlatform;
import com.facebook.buck.util.HumanReadableException;
import com.google.common.collect.ImmutableMap;
import java.nio.file.Path;
import java.util.Map;

/** A Halide-specific "view" of BuckConfig. */
public class HalideBuckConfig {
  public static final String HALIDE_SECTION_NAME = "halide";
  public static final String HALIDE_XCODE_COMPILE_SCRIPT_KEY = "xcode_compile_script";
  private static final String HALIDE_TARGET_KEY_PREFIX = "target_";

  private final BuckConfig delegate;

  public HalideBuckConfig(BuckConfig delegate) {
    this.delegate = delegate;
  }

  public String getHalideTargetForPlatform(CxxPlatform cxxPlatform) {
    String flavorName = cxxPlatform.getFlavor().toString();
    ImmutableMap<String, String> targetMap = getHalideTargetMap();
    if (!targetMap.containsKey(flavorName)) {
      throw new HumanReadableException(
          "No halide target found for platform: '%s'\n"
              + "Add one in .buckconfig in the halide section.\n"
              + "\n"
              + "Example:\n"
              + "\n"
              + "[halide]"
              + "\n"
              + "target_%s = x86-64-osx-user_context",
          flavorName, flavorName);
    }
    return targetMap.get(flavorName);
  }

  private ImmutableMap<String, String> getHalideTargetMap() {
    ImmutableMap<String, String> allEntries = delegate.getEntriesForSection(HALIDE_SECTION_NAME);
    ImmutableMap.Builder<String, String> targets = ImmutableMap.builder();
    for (Map.Entry<String, String> entry : allEntries.entrySet()) {
      if (entry.getKey().startsWith(HALIDE_TARGET_KEY_PREFIX)) {
        targets.put(entry.getKey().substring(HALIDE_TARGET_KEY_PREFIX.length()), entry.getValue());
      }
    }
    return targets.build();
  }

  /// Get the path to the Halide compile script for Xcode.
  public Path getXcodeCompileScriptPath() {
    return delegate.getRequiredPath(HALIDE_SECTION_NAME, HALIDE_XCODE_COMPILE_SCRIPT_KEY);
  }
}