// License: GPL. Copyright 2007 by Immanuel Scholz and others
package org.openstreetmap.josm.tools;

import static org.openstreetmap.josm.tools.I18n.tr;
import org.openstreetmap.josm.Main;

import java.awt.event.KeyEvent;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Collection;
import javax.swing.KeyStroke;
import javax.swing.JMenu;
import javax.swing.JOptionPane;

/**
 * Global shortcut class.
 *
 * Note: This class represents a single shortcut, contains the factory to obtain
 *       shortcut objects from, manages shortcuts and shortcut collisions, and
 *       finally manages loading and saving shortcuts to/from the preferences.
 *
 * Action authors: You only need the registerShortCut() factory. Ignore everything
 *                 else.
 *
 * All: Use only public methods that are also marked to be used. The others are
 *      public so the shortcut preferences can use them.
 *
 */
public class ShortCut {
	private String shortText;        // the unique ID of the shortcut
	private String longText;         // a human readable description that will be shown in the preferences
	private int requestedKey;        // the key, the caller requested
	private int requestedGroup;      // the group, the caller requested
	private int assignedKey;         // the key that actually is used
	private int assignedModifier;    // the modifiers that are used
	private boolean assignedDefault; // true if it got assigned what was requested. (Note: modifiers will be ignored in favour of group when loading it from the preferences then.)
	private boolean assignedUser;    // true if the user changed this shortcut
	private boolean automatic;       // true if the user cannot change this shortcut (Note: it also will not be saved into the preferences)
	private boolean reset;           // true if the user requested this shortcut to be set to its default value (will happen on next restart, as this shortcut will not be saved to the preferences)

	// simple constructor
	private ShortCut(String shortText, String longText, int requestedKey, int requestedGroup, int assignedKey, int assignedModifier, boolean assignedDefault, boolean assignedUser) {
		this.shortText = shortText;
		this.longText = longText;
		this.requestedKey = requestedKey;
		this.requestedGroup = requestedGroup;
		this.assignedKey = assignedKey;
		this.assignedModifier = assignedModifier;
		this.assignedDefault = assignedDefault;
		this.assignedUser = assignedUser;
		this.automatic = false;
		this.reset = false;
	}

	public String getShortText() {
		return shortText;
	}

	public String getLongText() {
		return longText;
	}

	// a shortcut will be renamed when it is handed out again, because the original name
	// may be a dummy
	private void setLongText(String longText) {
		this.longText = longText;
	}

	private int getRequestedKey() {
		return requestedKey;
	}

	public int getRequestedGroup() {
		return requestedGroup;
	}

	public int getAssignedKey() {
		return assignedKey;
	}

	public int getAssignedModifier() {
		return assignedModifier;
	}

	public boolean getAssignedDefault() {
		return assignedDefault;
	}

	public boolean getAssignedUser() {
		return assignedUser;
	}

	public boolean getAutomatic() {
		return automatic;
	}

	private boolean getReset() {
		return reset;
	}

	/**
	 * FOR PREF PANE ONLY
	 */
	public void setAutomatic() {
		automatic = true;
	}

	/**
	 * FOR PREF PANE ONLY
	 */
	public void setAssignedModifier(int assignedModifier) {
		this.assignedModifier = assignedModifier;
	}

	/**
	 * FOR PREF PANE ONLY
	 */
	public void setAssignedKey(int assignedKey) {
		this.assignedKey = assignedKey;
	}

	/**
	 * FOR PREF PANE ONLY
	 */
	public void setAssignedUser(boolean assignedUser) {
		this.reset = (!this.assignedUser && assignedUser);
		if (assignedUser) assignedDefault = false;
		this.assignedUser = assignedUser;
	}

	/**
	 * Use this to register the shortcut with Swing
	 */
	public KeyStroke getKeyStroke() {
		if (assignedModifier != -1) {
			return KeyStroke.getKeyStroke(assignedKey, assignedModifier);
		} else {
			return null;
		}
	}

	private boolean isSame(int isKey, int isModifier) {
		// -1 --- an unassigned shortcut is different from any other shortcut
		return( isKey == assignedKey && isModifier == assignedModifier && assignedModifier != Groups.get(GROUP_NONE));
	}

	// create a shortcut object from an string as saved in the preferences
	private ShortCut(String prefString) {
		String[] s = prefString.split(";");
		this.shortText = s[0];
		this.longText = s[1];
		this.requestedKey = Integer.parseInt(s[2]);
		this.requestedGroup = Integer.parseInt(s[3]);
		this.assignedKey = Integer.parseInt(s[4]);
		this.assignedModifier = Integer.parseInt(s[5]);
		this.assignedDefault = Boolean.parseBoolean(s[6]);
		this.assignedUser = Boolean.parseBoolean(s[7]);
	}

	// get a string that can be put into the preferences
	private String asPrefString() {
		return shortText + ";" + longText + ";" + requestedKey + ";" + requestedGroup + ";" + assignedKey + ";" + assignedModifier + ";" + assignedDefault + ";" + assignedUser;
	}

	private boolean isSame(ShortCut other) {
		return assignedKey == other.assignedKey && assignedModifier == other.assignedModifier;
	}

	/**
	 * use this to set a menu's mnemonic
	 */
	public void setMnemonic(JMenu menu) {
		if (requestedGroup == GROUP_MNEMONIC && assignedModifier == Groups.get(requestedGroup + GROUPS_DEFAULT) && getKeyStroke() != null && KeyEvent.getKeyText(assignedKey).length() == 1) {
			menu.setMnemonic(KeyEvent.getKeyText(assignedKey).charAt(0)); //getKeyStroke().getKeyChar() seems not to work here
		}
	}

	/**
	 * use this to get a human readable text for your shortcut
	 */
	 public String getKeyText() {
	 	KeyStroke keyStroke = getKeyStroke();
		if (keyStroke == null) return "";
		String modifText = KeyEvent.getKeyModifiersText(keyStroke.getModifiers());
		if ("".equals (modifText)) return KeyEvent.getKeyText (keyStroke.getKeyCode ());
		return modifText + "+" + KeyEvent.getKeyText(keyStroke.getKeyCode ());
	}

	  ///////////////////////////////
	 // everything's static below //
	///////////////////////////////

	// here we store our shortcuts
	private static Map<String, ShortCut> ShortCuts = new LinkedHashMap<String, ShortCut>();

	// and here our modifier groups
	private static Map<Integer, Integer> Groups = new HashMap<Integer, Integer>();

	// check if something collides with an existing shortcut
	private static ShortCut findShortcut(int requestedKey, int modifier) {
		if (modifier == Groups.get(GROUP_NONE)) {
			return null;
		}
		for (ShortCut sc : ShortCuts.values()) {
			if (sc.isSame(requestedKey, modifier)) {
				return sc;
			}
		}
		return null;
	}

	/**
	 * FOR PREF PANE ONLY
	 */
	public static Collection<ShortCut> listAll() {
		return ShortCuts.values();
	}

	// try to find an unused shortcut
	private static ShortCut findRandomShortcut(String shortText, String longText, int requestedKey, int requestedGroup) {
		int[] mods = {Groups.get(requestedGroup + GROUPS_DEFAULT), Groups.get(requestedGroup + GROUPS_ALT1), Groups.get(requestedGroup + GROUPS_ALT2)};
		for (int m : mods) {
			for (int k = KeyEvent.VK_A; k < KeyEvent.VK_Z; k++) { // we'll limit ourself to 100% safe keys
				if ( findShortcut(k, m) == null ) {
					return new ShortCut(shortText, longText, requestedKey, requestedGroup, k, m, false, false);
				}
			}
		}
		return new ShortCut(shortText, longText, requestedKey, requestedGroup, requestedKey, Groups.get(GROUP_NONE), false, false);
	}

	// use these constants to request shortcuts
	public static final int GROUP_NONE = 0;          // no shortcut
	public static final int GROUP_HOTKEY = 1;        // a button action, will use another modifier than MENU on system with a meta key
	public static final int GROUP_MENU = 2;          // a menu action, e.g. "ctrl-e"/"cmd-e" (export)
	public static final int GROUP_EDIT = 3;          // direct edit key, e.g. "a" (add)
	public static final int GROUP_LAYER = 4;         // toggle one of the right-hand-side windows, e.g. "alt-l" (layers)
	public static final int GROUP_DIRECT = 5;        // for non-letter keys, preferable without modifier, e.g. F5
	public static final int GROUP_MNEMONIC = 6;      // for use with Menu.setMnemonic() only!
	public static final int GROUP__MAX = 7;
	public static final int GROUP_RESERVED = 1000;
	public static final int GROUPS_DEFAULT = 0;
	public static final int GROUPS_ALT1 = GROUP__MAX;
	public static final int GROUPS_ALT2 = GROUP__MAX * 2;

	// safely read a shortcut from the preferences
	private static String[] getConfigStringArray(String key) {
		String s = Main.pref.get(key, null);
		if (s == null || s.equals("null") || s.equals(""))
			return null;
		return s.split(";");
	}

	// bootstrap
	private static boolean initdone = false;
	private static void doInit() {
		if (initdone) return;
		initdone = true;
		// if we have no modifier groups in the config, we have to create them
		if (Main.pref.get("shortcut.groups.configured", null) == null) {
			Main.platform.initShortCutGroups();
			Main.pref.put("shortcut.groups.configured", true);
			displayFirsttimeWarning();
		}
		// pull in the gorups
		for (int i = GROUP_NONE; i < GROUP__MAX+GROUPS_ALT2*2; i++) { // fill more groups, so registering with e.g. ALT2+MNEMONIC won't NPE
			Groups.put(new Integer(i), new Integer(Main.pref.getInteger("shortcut.groups."+i, -1)));
		}
		// (1) System reserved shortcuts
		Main.platform.initSystemShortCuts();
		// (2) User defined shortcuts
		int i = 0;
		String p = Main.pref.get("shortcut.shortcut."+i, null);
		while (p != null) {
			ShortCut sc = new ShortCut(p);
			if (sc.getAssignedUser()) registerShortCut(sc);
			i++;
			p = Main.pref.get("shortcut.shortcut."+i, null);
		}
		// Shortcuts at their default values
		i = 0;
		p = Main.pref.get("shortcut.shortcut."+i, null);
		while (p != null) {
			ShortCut sc = new ShortCut(p);
			if (!sc.getAssignedUser() && sc.getAssignedDefault()) registerShortCut(sc);
			i++;
			p = Main.pref.get("shortcut.shortcut."+i, null);
		}
		// Shortcuts that were automatically moved
		i = 0;
		p = Main.pref.get("shortcut.shortcut."+i, null);
		while (p != null) {
			ShortCut sc = new ShortCut(p);
			if (!sc.getAssignedUser() && !sc.getAssignedDefault()) registerShortCut(sc);
			i++;
			p = Main.pref.get("shortcut.shortcut."+i, null);
		}
	}

	// shutdown handling
	public static void savePrefs() {
// we save this directly from the preferences pane, so don't overwrite these values here
//		for (int i = GROUP_NONE; i < GROUP__MAX+GROUPS_ALT2; i++) {
//			Main.pref.put("shortcut.groups."+i, Groups.get(i).toString());
//		}
		int i = 0;
		for (ShortCut sc : ShortCuts.values()) {
			if (!sc.getAutomatic() && !sc.getReset()) {
				Main.pref.put("shortcut.shortcut."+i, sc.asPrefString());
				i++;
			}
		}
		Main.pref.put("shortcut.shortcut."+i, "");
	}

	// this is used to register a shortcut that was read from the preferences
	private static void registerShortCut(ShortCut sc) {
		if (sc.getAssignedDefault()) { // a 100% default shortcut will go though unchanged -- unless the groups have been reconfigured
			registerShortCut(sc.getShortText(), sc.getLongText(), sc.getRequestedKey(), sc.getRequestedGroup(), sc);
		} else if (sc.getAssignedUser()) { // put a user configured shortcut in as-is -- unless there's a conflict
			ShortCut potentialShortCut = findShortcut(sc.getAssignedKey(), sc.getAssignedModifier());
			if (potentialShortCut == null) {
				ShortCuts.put(sc.getShortText(), sc);
			} else {
				registerShortCut(sc.getShortText(), sc.getLongText(), sc.getRequestedKey(), sc.getRequestedGroup(), sc);
			}
		} else { // this shortcut was auto-moved before, re-register and warn if it changes
			registerShortCut(sc.getShortText(), sc.getLongText(), sc.getRequestedKey(), sc.getRequestedGroup(), sc);
		}
	}

	/**
	 * FOR PLATFORMHOOK USE ONLY
	 *
	 * This registers a system shortcut. See PlatformHook for details.
	 */
	public static ShortCut registerSystemCut(String shortText, String longText, int key, int modifier) {
		if (ShortCuts.containsKey(shortText)) {
			return ShortCuts.get(shortText);
		}
		ShortCut potentialShortCut = findShortcut(key, modifier);
		if (potentialShortCut != null) {
			// this always is a logic error in the hook
			System.err.println("CONFLICT WITH SYSTEM KEY "+shortText);
			return null;
		} else {
			potentialShortCut = new ShortCut(shortText, longText, key, GROUP_RESERVED, key, modifier, true, false);
			ShortCuts.put(shortText, potentialShortCut);
			return potentialShortCut;
		}
	}

	/**
	 * Register a shortcut.
	 *
	 * Here you get your shortcuts from. The parameters are:
	 *
	 * shortText - an ID. re-use a "system:*" ID if possible, else use something unique.
	 *             "menu:*" is reserved for menu mnemonics, "core:*" is reserved for
	 *             actions that are part of JOSM's core. Use something like
	 *             <pluginname>+":"+<actionname>
	 * longText - this will be displayed in the shortcut preferences dialog. Better
	 *            use soomething the user will recognize...
	 * requestedKey - the key you'd prefer. Use a KeyEvent.VK_* constant here.
	 * requestedGroup - the group this shortcut fits best. This will determine the
	 *                  modifiers your shortcut will get assigned. Use the GROUP_*
	 *                  constants defined above.
	 */
	public static ShortCut registerShortCut(String shortText, String longText, int requestedKey, int requestedGroup) {
		return registerShortCut(shortText, longText, requestedKey, requestedGroup, null);
	}

	// and now the workhorse. same parameters as above, just one more: if originalShortCut is not null and
	// is different from the shortcut that will be assigned, a popup warning will be displayed to the user.
	// This is used when registering shortcuts that have been visible to the user before (read: have been
	// read from the preferences file). New shortcuts will never warn, even when they land on some funny
	// random fallback key like Ctrl+Alt+Shift+Z for "File Open..." <g>
	private static ShortCut registerShortCut(String shortText, String longText, int requestedKey, int requestedGroup, ShortCut originalShortCut) {
		doInit();
		if (ShortCuts.containsKey(shortText)) { // a re-register? maybe a sc already read from the preferences?
			ShortCut sc = ShortCuts.get(shortText);
			sc.setLongText(longText); // or set by the platformHook, in this case the original longText doesn't match the real action
			return sc;
		}
		Integer defaultModifier = Groups.get(requestedGroup + GROUPS_DEFAULT);
		if (defaultModifier == null) { // garbage in, no shortcurt out
			defaultModifier = Groups.get(GROUP_NONE + GROUPS_DEFAULT);
		}
		ShortCut conflictsWith = null;
		ShortCut potentialShortCut = findShortcut(requestedKey, defaultModifier);
		if (potentialShortCut != null) { // 3 stage conflict handling
			conflictsWith = potentialShortCut;
			defaultModifier = Groups.get(requestedGroup + GROUPS_ALT1);
			if (defaultModifier == null) { // garbage in, no shortcurt out
				defaultModifier = Groups.get(GROUP_NONE + GROUPS_DEFAULT);
			}
			potentialShortCut = findShortcut(requestedKey, defaultModifier);
			if (potentialShortCut != null) {
				defaultModifier = Groups.get(requestedGroup + GROUPS_ALT2);
				if (defaultModifier == null) { // garbage in, no shortcurt out
					defaultModifier = Groups.get(GROUP_NONE + GROUPS_DEFAULT);
				}
				potentialShortCut = findShortcut(requestedKey, defaultModifier);
				if (potentialShortCut != null) { // if all 3 modifiers for a group are used, we give up
					potentialShortCut = findRandomShortcut(shortText, longText, requestedKey, requestedGroup);
				} else {
					potentialShortCut = new ShortCut(shortText, longText, requestedKey, requestedGroup, requestedKey, defaultModifier, false, false);
				}
			} else {
				potentialShortCut = new ShortCut(shortText, longText, requestedKey, requestedGroup, requestedKey, defaultModifier, false, false);
			}
			if (originalShortCut != null && !originalShortCut.isSame(potentialShortCut)) {
				displayWarning(conflictsWith, potentialShortCut, shortText, longText);
			} else if (originalShortCut == null) {
				System.out.println("Silent shortcut conflict: '"+shortText+"' moved by '"+conflictsWith.getShortText()+"' to '"+potentialShortCut.getKeyText()+"'.");
			}
		} else {
			potentialShortCut = new ShortCut(shortText, longText, requestedKey, requestedGroup, requestedKey, defaultModifier, true, false);
		}
		ShortCuts.put(shortText, potentialShortCut);
		return potentialShortCut;
	}

	// a lengthy warning message
	private static void displayWarning(ShortCut conflictsWith, ShortCut potentialShortCut, String shortText, String longText) {
		JOptionPane.showMessageDialog(Main.parent, tr("Setting the keyboard shortcut ''{0}'' for the action ''{1}'' ({2}) failed\n"+
		                                              "because the shortcut is already taken by the action ''{3}'' ({4}).\n\n",
		                                              conflictsWith.getKeyText(), longText, shortText,
		                                              conflictsWith.getLongText(), conflictsWith.getShortText())+
		                                              (potentialShortCut.getKeyText().equals("") ?
		                                              	tr("This action will have no shortcut.\n\n")
		                                              :
		                                              	tr("Using the shortcut ''{0}'' instead.\n\n", potentialShortCut.getKeyText())
		                                              )+
		                                              tr("(Hint: You can edit the shortcuts in the preferences.)")
		                             );
	}

	private static void displayFirsttimeWarning() {
		JOptionPane.showMessageDialog(Main.parent, tr("NEW!\nJOSM now support keyboard configuration.\n\nHowever, some of the defaults have "
		+"changed.\nPlease check (and configure) the keyboard shortcuts carefully\nto avoid losing your work accidentially."));
	}
}