/*
    * Copyright 2020-2022 The OSHI Project Contributors
    * SPDX-License-Identifier: MIT
    */
   package oshi.hardware.platform.linux;
   
   import java.util.ArrayList;
   import java.util.List;
   
  import oshi.annotation.concurrent.Immutable;
  import oshi.hardware.GraphicsCard;
  import oshi.hardware.common.AbstractGraphicsCard;
  import oshi.util.Constants;
  import oshi.util.ExecutingCommand;
  import oshi.util.ParseUtil;
  import oshi.util.tuples.Pair;
  
  /**
   * Graphics card info obtained by lshw
   */
  @Immutable
  final class LinuxGraphicsCard extends AbstractGraphicsCard {
  
      /**
       * Constructor for LinuxGraphicsCard
       *
       * @param name        The name
       * @param deviceId    The device ID
       * @param vendor      The vendor
       * @param versionInfo The version info
       * @param vram        The VRAM
       */
      LinuxGraphicsCard(String name, String deviceId, String vendor, String versionInfo, long vram) {
          super(name, deviceId, vendor, versionInfo, vram);
      }
  
      /**
       * public method used by {@link oshi.hardware.common.AbstractHardwareAbstractionLayer} to access the graphics cards.
       *
       * @return List of {@link oshi.hardware.platform.linux.LinuxGraphicsCard} objects.
       */
      public static List<GraphicsCard> getGraphicsCards() {
          List<GraphicsCard> cardList = getGraphicsCardsFromLspci();
          if (cardList.isEmpty()) {
              cardList = getGraphicsCardsFromLshw();
          }
          return cardList;
      }
  
      // Faster, use as primary
      private static List<GraphicsCard> getGraphicsCardsFromLspci() {
          List<GraphicsCard> cardList = new ArrayList<>();
          // Machine readable version
          List<String> lspci = ExecutingCommand.runNative("lspci -vnnm");
          String name = Constants.UNKNOWN;
          String deviceId = Constants.UNKNOWN;
          String vendor = Constants.UNKNOWN;
          List<String> versionInfoList = new ArrayList<>();
          boolean found = false;
          String lookupDevice = null;
          for (String line : lspci) {
              String[] split = line.trim().split(":", 2);
              String prefix = split[0];
              // Skip until line contains "VGA"
              if (prefix.equals("Class") && line.contains("VGA")) {
                  found = true;
              } else if (prefix.equals("Device") && !found && split.length > 1) {
                  lookupDevice = split[1].trim();
              }
              if (found) {
                  if (split.length < 2) {
                      // Save previous card
                      cardList.add(new LinuxGraphicsCard(name, deviceId, vendor,
                              versionInfoList.isEmpty() ? Constants.UNKNOWN : String.join(", ", versionInfoList),
                              queryLspciMemorySize(lookupDevice)));
                      versionInfoList.clear();
                      found = false;
                  } else {
                      if (prefix.equals("Device")) {
                          Pair<String, String> pair = ParseUtil.parseLspciMachineReadable(split[1].trim());
                          if (pair != null) {
                              name = pair.getA();
                              deviceId = "0x" + pair.getB();
                          }
                      } else if (prefix.equals("Vendor")) {
                          Pair<String, String> pair = ParseUtil.parseLspciMachineReadable(split[1].trim());
                          if (pair != null) {
                              vendor = pair.getA() + " (0x" + pair.getB() + ")";
                          } else {
                              vendor = split[1].trim();
                          }
                      } else if (prefix.equals("Rev:")) {
                          versionInfoList.add(line.trim());
                      }
                  }
              }
          }
          // If we haven't yet written the last card do so now
          if (found) {
             cardList.add(new LinuxGraphicsCard(name, deviceId, vendor,
                     versionInfoList.isEmpty() ? Constants.UNKNOWN : String.join(", ", versionInfoList),
                     queryLspciMemorySize(lookupDevice)));
         }
         return cardList;
     }
 
     private static long queryLspciMemorySize(String lookupDevice) {
         long vram = 0L;
         // Lookup memory
         // Human readable version, includes memory
         List<String> lspciMem = ExecutingCommand.runNative("lspci -v -s " + lookupDevice);
         for (String mem : lspciMem) {
             if (mem.contains(" prefetchable")) {
                 vram += ParseUtil.parseLspciMemorySize(mem);
             }
         }
         return vram;
     }
 
     // Slower, use as backup
     private static List<GraphicsCard> getGraphicsCardsFromLshw() {
         List<GraphicsCard> cardList = new ArrayList<>();
         List<String> lshw = ExecutingCommand.runNative("lshw -C display");
         String name = Constants.UNKNOWN;
         String deviceId = Constants.UNKNOWN;
         String vendor = Constants.UNKNOWN;
         List<String> versionInfoList = new ArrayList<>();
         long vram = 0;
         int cardNum = 0;
         for (String line : lshw) {
             String[] split = line.trim().split(":");
             if (split[0].startsWith("*-display")) {
                 // Save previous card
                 if (cardNum++ > 0) {
                     cardList.add(new LinuxGraphicsCard(name, deviceId, vendor,
                             versionInfoList.isEmpty() ? Constants.UNKNOWN : String.join(", ", versionInfoList), vram));
                     versionInfoList.clear();
                 }
             } else if (split.length == 2) {
                 String prefix = split[0];
                 if (prefix.equals("product")) {
                     name = split[1].trim();
                 } else if (prefix.equals("vendor")) {
                     vendor = split[1].trim();
                 } else if (prefix.equals("version")) {
                     versionInfoList.add(line.trim());
                 } else if (prefix.startsWith("resources")) {
                     vram = ParseUtil.parseLshwResourceString(split[1].trim());
                 }
             }
         }
         cardList.add(new LinuxGraphicsCard(name, deviceId, vendor,
                 versionInfoList.isEmpty() ? Constants.UNKNOWN : String.join(", ", versionInfoList), vram));
         return cardList;
     }
 }