/*
    * Copyright (C) 2018-2022, Andre Bossert <andre.bossert@siemens.com>
    * Copyright (C) 2019, Tim Neumann <tim.neumann@advantest.com>
    *
    * This program and the accompanying materials are made available under the
    * terms of the Eclipse Distribution License v. 1.0 which is available at
    * https://www.eclipse.org/org/documents/edl-v10.php.
    *
    * SPDX-License-Identifier: BSD-3-Clause
   */
  
  package org.eclipse.jgit.internal.diffmergetool;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.Collections;
  import java.util.LinkedHashSet;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.Optional;
  import java.util.Set;
  import java.util.TreeMap;
  
  import org.eclipse.jgit.internal.JGitText;
  import org.eclipse.jgit.lib.Repository;
  import org.eclipse.jgit.lib.StoredConfig;
  import org.eclipse.jgit.lib.internal.BooleanTriState;
  import org.eclipse.jgit.treewalk.TreeWalk;
  import org.eclipse.jgit.util.FS;
  import org.eclipse.jgit.util.FS.ExecutionResult;
  import org.eclipse.jgit.util.StringUtils;
  
  /**
   * Manages diff tools.
   */
  public class DiffTools {
  
  	private final FS fs;
  
  	private final File gitDir;
  
  	private final File workTree;
  
  	private final DiffToolConfig config;
  
  	private final Repository repo;
  
  	private final Map<String, ExternalDiffTool> predefinedTools;
  
  	private final Map<String, ExternalDiffTool> userDefinedTools;
  
  	/**
  	 * Creates the external diff-tools manager for given repository.
  	 *
  	 * @param repo
  	 *            the repository
  	 */
  	public DiffTools(Repository repo) {
  		this(repo, repo.getConfig());
  	}
  
  	/**
  	 * Creates the external merge-tools manager for given configuration.
  	 *
  	 * @param config
  	 *            the git configuration
  	 */
  	public DiffTools(StoredConfig config) {
  		this(null, config);
  	}
  
  	private DiffTools(Repository repo, StoredConfig config) {
  		this.repo = repo;
  		this.config = config.get(DiffToolConfig.KEY);
  		this.gitDir = repo == null ? null : repo.getDirectory();
  		this.fs = repo == null ? FS.DETECTED : repo.getFS();
  		this.workTree = repo == null ? null : repo.getWorkTree();
  		predefinedTools = setupPredefinedTools();
  		userDefinedTools = setupUserDefinedTools(predefinedTools);
  	}
  
  	/**
  	 * Compare two versions of a file.
  	 *
  	 * @param localFile
  	 *            The local/left version of the file.
  	 * @param remoteFile
  	 *            The remote/right version of the file.
  	 * @param toolName
  	 *            Optionally the name of the tool to use. If not given the
  	 *            default tool will be used.
  	 * @param prompt
  	 *            Optionally a flag whether to prompt the user before compare.
  	 *            If not given the default will be used.
  	 * @param gui
  	 *            A flag whether to prefer a gui tool.
  	 * @param trustExitCode
  	 *            Optionally a flag whether to trust the exit code of the tool.
  	 *            If not given the default will be used.
 	 * @param promptHandler
 	 *            The handler to use when needing to prompt the user if he wants
 	 *            to continue.
 	 * @param noToolHandler
 	 *            The handler to use when needing to inform the user, that no
 	 *            tool is configured.
 	 * @return the optional result of executing the tool if it was executed
 	 * @throws ToolException
 	 *             when the tool fails
 	 */
 	public Optional<ExecutionResult> compare(FileElement localFile,
 			FileElement remoteFile, Optional<String> toolName,
 			BooleanTriState prompt, boolean gui, BooleanTriState trustExitCode,
 			PromptContinueHandler promptHandler,
 			InformNoToolHandler noToolHandler) throws ToolException {
 
 		String toolNameToUse;
 
 		if (toolName == null) {
 			throw new ToolException(JGitText.get().diffToolNullError);
 		}
 
 		if (toolName.isPresent()) {
 			toolNameToUse = toolName.get();
 		} else {
 			toolNameToUse = getDefaultToolName(gui);
 		}
 
 		if (StringUtils.isEmptyOrNull(toolNameToUse)) {
 			throw new ToolException(JGitText.get().diffToolNotGivenError);
 		}
 
 		boolean doPrompt;
 		if (prompt != BooleanTriState.UNSET) {
 			doPrompt = prompt == BooleanTriState.TRUE;
 		} else {
 			doPrompt = isInteractive();
 		}
 
 		if (doPrompt) {
 			if (!promptHandler.prompt(toolNameToUse)) {
 				return Optional.empty();
 			}
 		}
 
 		boolean trust;
 		if (trustExitCode != BooleanTriState.UNSET) {
 			trust = trustExitCode == BooleanTriState.TRUE;
 		} else {
 			trust = config.isTrustExitCode();
 		}
 
 		ExternalDiffTool tool = getTool(toolNameToUse);
 		if (tool == null) {
 			throw new ToolException(
 					"External diff tool is not defined: " + toolNameToUse); //$NON-NLS-1$
 		}
 
 		return Optional.of(
 				compare(localFile, remoteFile, tool, trust));
 	}
 
 	/**
 	 * Compare two versions of a file.
 	 *
 	 * @param localFile
 	 *            the local file element
 	 * @param remoteFile
 	 *            the remote file element
 	 * @param tool
 	 *            the selected tool
 	 * @param trustExitCode
 	 *            the "trust exit code" option
 	 * @return the execution result from tool
 	 * @throws ToolException
 	 */
 	public ExecutionResult compare(FileElement localFile,
 			FileElement remoteFile, ExternalDiffTool tool,
 			boolean trustExitCode) throws ToolException {
 		try {
 			if (tool == null) {
 				throw new ToolException(JGitText
 						.get().diffToolNotSpecifiedInGitAttributesError);
 			}
 			// prepare the command (replace the file paths)
 			String command = ExternalToolUtils.prepareCommand(tool.getCommand(),
 					localFile, remoteFile, null, null);
 			// prepare the environment
 			Map<String, String> env = ExternalToolUtils.prepareEnvironment(
 					gitDir, localFile, remoteFile, null, null);
 			// execute the tool
 			CommandExecutor cmdExec = new CommandExecutor(fs, trustExitCode);
 			return cmdExec.run(command, workTree, env);
 		} catch (IOException | InterruptedException e) {
 			throw new ToolException(e);
 		} finally {
 			localFile.cleanTemporaries();
 			remoteFile.cleanTemporaries();
 		}
 	}
 
 	/**
 	 * Get user defined tool names.
 	 *
 	 * @return the user defined tool names
 	 */
 	public Set<String> getUserDefinedToolNames() {
 		return userDefinedTools.keySet();
 	}
 
 	/**
 	 * Get predefined tool names.
 	 *
 	 * @return the predefined tool names
 	 */
 	public Set<String> getPredefinedToolNames() {
 		return predefinedTools.keySet();
 	}
 
 	/**
 	 * Get all tool names.
 	 *
 	 * @return the all tool names (default or available tool name is the first
 	 *         in the set)
 	 */
 	public Set<String> getAllToolNames() {
 		String defaultName = getDefaultToolName(false);
 		if (defaultName == null) {
 			defaultName = getFirstAvailableTool();
 		}
 		return ExternalToolUtils.createSortedToolSet(defaultName,
 				getUserDefinedToolNames(), getPredefinedToolNames());
 	}
 
 	/**
 	 * Provides {@link Optional} with the name of an external diff tool if
 	 * specified in git configuration for a path.
 	 *
 	 * The formed git configuration results from global rules as well as merged
 	 * rules from info and worktree attributes.
 	 *
 	 * Triggers {@link TreeWalk} until specified path found in the tree.
 	 *
 	 * @param path
 	 *            path to the node in repository to parse git attributes for
 	 * @return name of the difftool if set
 	 * @throws ToolException
 	 */
 	public Optional<String> getExternalToolFromAttributes(final String path)
 			throws ToolException {
 		return ExternalToolUtils.getExternalToolFromAttributes(repo, path,
 				ExternalToolUtils.KEY_DIFF_TOOL);
 	}
 
 	/**
 	 * Checks the availability of the predefined tools in the system.
 	 *
 	 * @return set of predefined available tools
 	 */
 	public Set<String> getPredefinedAvailableTools() {
 		Map<String, ExternalDiffTool> defTools = getPredefinedTools(true);
 		Set<String> availableTools = new LinkedHashSet<>();
 		for (Entry<String, ExternalDiffTool> elem : defTools.entrySet()) {
 			if (elem.getValue().isAvailable()) {
 				availableTools.add(elem.getKey());
 			}
 		}
 		return availableTools;
 	}
 
 	/**
 	 * Get user defined tools map.
 	 *
 	 * @return the user defined tools
 	 */
 	public Map<String, ExternalDiffTool> getUserDefinedTools() {
 		return Collections.unmodifiableMap(userDefinedTools);
 	}
 
 	/**
 	 * Get predefined tools map.
 	 *
 	 * @param checkAvailability
 	 *            true: for checking if tools can be executed; ATTENTION: this
 	 *            check took some time, do not execute often (store the map for
 	 *            other actions); false: availability is NOT checked:
 	 *            isAvailable() returns default false is this case!
 	 * @return the predefined tools with optionally checked availability (long
 	 *         running operation)
 	 */
 	public Map<String, ExternalDiffTool> getPredefinedTools(
 			boolean checkAvailability) {
 		if (checkAvailability) {
 			for (ExternalDiffTool tool : predefinedTools.values()) {
 				PreDefinedDiffTool predefTool = (PreDefinedDiffTool) tool;
 				predefTool.setAvailable(ExternalToolUtils.isToolAvailable(fs,
 						gitDir, workTree, predefTool.getPath()));
 			}
 		}
 		return Collections.unmodifiableMap(predefinedTools);
 	}
 
 	/**
 	 * Get first available tool name.
 	 *
 	 * @return the name of first available predefined tool or null
 	 */
 	public String getFirstAvailableTool() {
 		for (ExternalDiffTool tool : predefinedTools.values()) {
 			if (ExternalToolUtils.isToolAvailable(fs, gitDir, workTree,
 					tool.getPath())) {
 				return tool.getName();
 			}
 		}
 		return null;
 	}
 
 	/**
 	 * Get default (gui-)tool name.
 	 *
 	 * @param gui
 	 *            use the diff.guitool setting ?
 	 * @return the default tool name
 	 */
 	public String getDefaultToolName(boolean gui) {
 		String guiToolName;
 		if (gui) {
 			guiToolName = config.getDefaultGuiToolName();
 			if (guiToolName != null) {
 				return guiToolName;
 			}
 		}
 		return config.getDefaultToolName();
 	}
 
 	/**
 	 * Is interactive diff (prompt enabled) ?
 	 *
 	 * @return is interactive (config prompt enabled) ?
 	 */
 	public boolean isInteractive() {
 		return config.isPrompt();
 	}
 
 	private ExternalDiffTool getTool(final String name) {
 		ExternalDiffTool tool = userDefinedTools.get(name);
 		if (tool == null) {
 			tool = predefinedTools.get(name);
 		}
 		return tool;
 	}
 
 	private static Map<String, ExternalDiffTool> setupPredefinedTools() {
 		Map<String, ExternalDiffTool> tools = new TreeMap<>();
 		for (CommandLineDiffTool tool : CommandLineDiffTool.values()) {
 			tools.put(tool.name(), new PreDefinedDiffTool(tool));
 		}
 		return tools;
 	}
 
 	private Map<String, ExternalDiffTool> setupUserDefinedTools(
 			Map<String, ExternalDiffTool> predefTools) {
 		Map<String, ExternalDiffTool> tools = new TreeMap<>();
 		Map<String, ExternalDiffTool> userTools = config.getTools();
 		for (String name : userTools.keySet()) {
 			ExternalDiffTool userTool = userTools.get(name);
 			// if difftool.<name>.cmd is defined we have user defined tool
 			if (userTool.getCommand() != null) {
 				tools.put(name, userTool);
 			} else if (userTool.getPath() != null) {
 				// if difftool.<name>.path is defined we just overload the path
 				// of predefined tool
 				PreDefinedDiffTool predefTool = (PreDefinedDiffTool) predefTools
 						.get(name);
 				if (predefTool != null) {
 					predefTool.setPath(userTool.getPath());
 				}
 			}
 		}
 		return tools;
 	}
 
 }