/*
 * Widgets/FindBar.cs
 *
 * Author(s)
 *  Gabriel Burt  <gabriel.burt@gmail.com>
 *  Stephane Delcroix  <stephane@delcroix.org>
 * 
 * This is free software. See COPYING for details.
 */

using System;
using System.Collections;
using System.Text.RegularExpressions;
using Gtk;
using Gdk;
using Mono.Unix;

using FSpot.Query;

namespace FSpot.Widgets {
	public class HighlightedBox : EventBox {
        private bool changing_style = false;

		public HighlightedBox(Widget child) : base()
        {
            Child = child;
            AppPaintable = true;
        }

        protected override void OnStyleSet(Style style)
        {
            if (!changing_style) {
                changing_style = true;
                ModifyBg(StateType.Normal, Style.Background(StateType.Selected));
                changing_style = false;
            }
        }

        protected override bool OnExposeEvent(Gdk.EventExpose evnt)
        {
            GdkWindow.DrawRectangle(Style.ForegroundGC(StateType.Normal), false, 0, 0, Allocation.Width - 1, Allocation.Height - 1);
            return base.OnExposeEvent(evnt);
        }
    }

	public class FindBar : HighlightedBox {
		private Entry entry;
		private string last_entry_text = String.Empty;
		private int open_parens = 0, close_parens = 0;
		private PhotoQuery query;
		private Term root_term = null;
        private HBox box;

		/*
		 * Properties
		 */
		public bool Completing {
			get {
				return (entry.Completion as LogicEntryCompletion).Completing;
			}
		}

		public Gtk.Entry Entry {
			get { return entry; }
		}

		public Term RootTerm  {
			get { return root_term; }
		}

		/*
		 * Constructor
		 */
		public FindBar (PhotoQuery query, TreeModel model) : base(new HBox())
		{
			this.query = query;

            box = Child as HBox;

			box.Spacing = 6;
            box.BorderWidth = 2;

			box.PackStart (new Label (Catalog.GetString ("Find:")), false, false, 0);

			entry = new Entry ();
			entry.Completion = new LogicEntryCompletion (entry, model);

			entry.TextInserted  += HandleEntryTextInserted;
			entry.TextDeleted   += HandleEntryTextDeleted;
			entry.KeyPressEvent += HandleEntryKeyPress;

			box.PackStart (entry, true, true, 0);

			Button clear_button = new Gtk.Button ();
			clear_button.Add (new Gtk.Image ("gtk-close", Gtk.IconSize.Button));
			clear_button.Clicked += HandleCloseButtonClicked;
			clear_button.Relief = Gtk.ReliefStyle.None;
			box.PackStart (clear_button, false, false, 0);
		}

		/*
		 * Event Handlers
		 */

		private void HandleCloseButtonClicked (object sender, EventArgs args)
		{
			Clear ();
		}

		private void HandleEntryTextInserted (object sender, TextInsertedArgs args)
		{
			//Console.WriteLine ("inserting {0}, ( = {1}  ) = {2}", args.Text, open_parens, close_parens);

			//int start = args.Position - args.Length;

			for (int i = 0; i < args.Text.Length; i++) {
				char c = args.Text [i];
				if (c == '(')
					open_parens++;
				else if (c == ')')
					close_parens++;
			}

			int pos = entry.Position + 1;
			int close_parens_needed = open_parens - close_parens;
			for (int i = 0; i < close_parens_needed; i++) {
				entry.TextInserted -= HandleEntryTextInserted;
				entry.InsertText (")", ref pos);
				close_parens++;
				entry.TextInserted += HandleEntryTextInserted;
				pos++;
			}
			//Console.WriteLine ("done w/ insert, {0}, ( = {1}  ) = {2}", args.Text, open_parens, close_parens);
			last_entry_text = entry.Text;

			QueueUpdate ();
		}

		private void HandleEntryTextDeleted (object sender, TextDeletedArgs args)
		{
			int length = args.EndPos - args.StartPos;
			//Console.WriteLine ("start {0} end {1} len {2} last {3}", args.StartPos, args.EndPos, length, last_entry_text);
			string txt = last_entry_text.Substring (args.StartPos, length);

			for (int i = 0; i < txt.Length; i++) {
				if (txt [i] == '(')
					open_parens--;
				else if (txt [i] == ')')
					close_parens--;
			}

			last_entry_text = entry.Text;

			QueueUpdate ();
		}

		private void HandleEntryKeyPress (object sender, KeyPressEventArgs args)
		{
			//bool shift = ModifierType.ShiftMask == (args.Event.State & ModifierType.ShiftMask);

			switch (args.Event.Key) {
			case (Gdk.Key.Escape):
				Clear ();
				args.RetVal = true;
				break;

			case (Gdk.Key.Tab):
				// If we are at the end of the entry box, let the normal Tab handler do its job
				if (entry.Position == entry.Text.Length) {
					args.RetVal = false;
					return;
				}

				// Go until the current character is an open paren
				while (entry.Position < entry.Text.Length && entry.Text [entry.Position] != '(')
					entry.Position++;

				// Put the cursor right after the open paren
				entry.Position++;

				args.RetVal = true;
				break;

			default:
				args.RetVal = false;
				break;
			}
		}

		/*
		 * Helper methods.
		 */

		private void Clear ()
		{
			entry.Text = String.Empty;
			Hide ();
		}

		// OPS The operators we support, case insensitive
		//private static string op_str = "(?'Ops' or | and |, | \\s+ )";
		private static string op_str = "(?'Ops' or | and |, )";

		// Match literals, eg tags or other text to search on
		private static string literal_str = "[^{0}{1}]+?";
		//private static string not_literal_str = "not\\s*\\((?'NotTag'[^{0}{1}]+)\\)";

		// Match a group surrounded by parenthesis and one or more terms separated by operators
		private static string term_str = "(((?'Open'{0})(?'Pre'[^{0}{1}]*?))+((?'Close-Open'{1})(?'Post'[^{0}{1}]*?))+)*?(?(Open)(?!))";

		// Match a group surrounded by parenthesis and one or more terms separated by operators, surrounded by not()
		//private static string not_term_str = String.Format("not\\s*(?'NotTerm'{0})", term_str);

		// Match a simple term or a group term or a not(group term)
		//private static string comb_term_str = String.Format ("(?'Term'{0}|{2}|{1})", simple_term_str, term_str, not_term_str);
		private static string comb_term_str = String.Format ("(?'Term'{0}|{1})|not\\s*\\((?'NotTerm'{0})\\)|not\\s*(?'NotTerm'{1})", literal_str, term_str);

		// Match a single term or a set of terms separated by operators
		private static string regex_str = String.Format ("^((?'Terms'{0}){1})*(?'Terms'{0})$", comb_term_str, op_str);

		private static Regex term_regex = new Regex (
							  String.Format (regex_str, "\\(", "\\)"),
							  RegexOptions.IgnoreCase | RegexOptions.Compiled
						  );

		// Debug method used to print results to verify the regex
		private static void PrintGroup (GroupCollection groups, string name)
		{
			Group group = groups [name];
			Console.WriteLine ("Name: {2} (success = {1}) group: {0}", group, group.Success, name);
			foreach (Capture capture in group.Captures) {
				Console.WriteLine ("  Have capture: {0}", capture);
			}
		}

		// Breaking the query the user typed into something useful involves running
		// it through the above regular expression recursively until it is broken down
		// into literals and operators that we can use to generate SQL queries.
		private bool ConstructQuery (Term parent, int depth, string txt)
		{
			return ConstructQuery(parent, depth, txt, false);
		}

		private bool ConstructQuery (Term parent, int depth, string txt, bool negated)
		{
			if (txt == null || txt.Length == 0)
				return true;

			string indent = String.Format ("{0," + depth*2 + "}", " ");

			//Console.WriteLine (indent + "Have text: {0}", txt);

			// Match the query the user typed against our regular expression
			Match match = term_regex.Match (txt);

			if (!match.Success) {
				//Console.WriteLine (indent + "Failed to match.");
				return false;
			}

			bool op_valid = true;
			string op = String.Empty;

			// For the moment at least we don't support operator precedence, so we require
			// that only a single operator is used for any given term unless it is made unambiguous
			// by using parenthesis.
			foreach (Capture capture in match.Groups ["Ops"].Captures) {
				if (op == String.Empty)
					op = capture.Value;
				else if (op != capture.Value) {
					op_valid = false;
					break;
				}
			}

			if (!op_valid) {
				Console.WriteLine (indent + "Ambiguous operator sequence.  Use parenthesis to explicitly define evaluation order.");
				return false;
			}

			if (match.Groups ["Terms"].Captures.Count == 1 && match.Groups["NotTerm"].Captures.Count != 1) {
				//Console.WriteLine (indent + "Unbreakable term: {0}", match.Groups ["Terms"].Captures [0]);
				string literal;
				bool is_negated = false;
				Tag tag = null;


				if (match.Groups ["NotTag"].Captures.Count == 1) {
					literal = match.Groups ["NotTag"].Captures [0].Value;
					is_negated = true;
				} else {
					literal = match.Groups ["Terms"].Captures [0].Value;
				}

				is_negated = is_negated || negated;

				tag = MainWindow.Toplevel.Database.Tags.GetTagByName (literal);

				// New OR term so we can match against both tag and text search
				parent = new OrTerm(parent, null);

				// If the literal is the name of a tag, include it in the OR
				AbstractLiteral term = null;
				if (tag != null) {
					new Literal (parent, tag, null);
				}

				// Always include the literal text in the search (path, comment, etc)
				new TextLiteral (parent, literal);

				// If the term was negated, negate the OR parent term
				if (is_negated) {
					parent = parent.Invert(true);
				}

				if (RootTerm == null)
					root_term = parent;

				return true;
			} else {
				Term us = null;
				if (op != null && op != String.Empty) {
					us = Term.TermFromOperator (op, parent, null);
					if (RootTerm == null)
						root_term = us;
				}

				foreach (Capture capture in match.Groups ["Term"].Captures) {
					string subterm = capture.Value.Trim ();

					if (subterm == null || subterm.Length == 0)
						continue;

					// Strip leading/trailing parens
					if (subterm [0] == '(' && subterm [subterm.Length - 1] == ')') {
						subterm = subterm.Remove (subterm.Length - 1, 1);
						subterm = subterm.Remove (0, 1);
					}

					//Console.WriteLine (indent + "Breaking subterm apart: {0}", subterm);

					if (!ConstructQuery (us, depth + 1, subterm, negated))
						return false;
				}

				foreach (Capture capture in match.Groups ["NotTerm"].Captures) {
					string subterm = capture.Value.Trim ();

					if (subterm == null || subterm.Length == 0)
						continue;

					// Strip leading/trailing parens
					if (subterm [0] == '(' && subterm [subterm.Length - 1] == ')') {
						subterm = subterm.Remove (subterm.Length - 1, 1);
						subterm = subterm.Remove (0, 1);
					}

					//Console.WriteLine (indent + "Breaking not subterm apart: {0}", subterm);

					if (!ConstructQuery (us, depth + 1, subterm, true))
						return false;
				}

				if (negated && us != null) {
					if (us == RootTerm)
						root_term = us.Invert(false);
					else
						us.Invert(false);
				}

				return true;
			}
		}

		private bool updating = false;
		private uint update_timeout_id = 0;
		private void QueueUpdate ()
		{
			if (updating || update_timeout_id != 0) {
				lock(this) {
					// If there is a timer set and we are not yet handling its timeout, then remove the timer
					// so we delay its trigger for another 500ms.
					if (!updating && update_timeout_id != 0)
						GLib.Source.Remove (update_timeout_id);

					// Assuming we're not currently handling a timeout, add a new timer
					if (!updating)
						update_timeout_id = GLib.Timeout.Add(500, OnUpdateTimer);
				}
			} else {
				// If we are not updating and there isn't a timer already set, then there is
				// no risk of race condition with the  timeout handler.
				update_timeout_id = GLib.Timeout.Add(500, OnUpdateTimer);
			}
		}

		private bool OnUpdateTimer ()
		{
			lock(this) {
				updating = true;
			}

			Update();

			lock(this) {
				updating = false;
				update_timeout_id = 0;
			}

			return false;
		}

		private void Update ()
		{
			// Clear the last root term
			root_term = null;

			if (ParensValid () && ConstructQuery (null, 0, entry.Text)) {
				if (RootTerm != null) {
					//Console.WriteLine("rootTerm = {0}", RootTerm);
					if (!(RootTerm is AndTerm)) {
						// A little hacky, here to make sure the root term is a AndTerm which will
						// ensure we handle the Hidden tag properly
						AndTerm root_parent = new AndTerm(null, null);
						RootTerm.Parent = root_parent;
						root_term = root_parent;
					}

					//Console.WriteLine("rootTerm = {0}", RootTerm);
					if (!(RootTerm is AndTerm)) {
						// A little hacky, here to make sure the root term is a AndTerm which will
						// ensure we handle the Hidden tag properly
						AndTerm root_parent = new AndTerm(null, null);
						RootTerm.Parent = root_parent;
						root_term = root_parent;
					}
					//Console.WriteLine ("condition = {0}", RootTerm.SqlCondition ());
					query.ExtraCondition = RootTerm.SqlCondition ();
				} else {
					query.ExtraCondition = null;
					//Console.WriteLine ("root term is null");
				}
			}
		}

		private bool ParensValid ()
		{
			for (int i = 0; i < entry.Text.Length; i++) {
				if (entry.Text [i] == '(' || entry.Text [i] == ')') {
					int pair_pos = ParenPairPosition (entry.Text, i);

					if (pair_pos == -1)
						return false;
				}
			}

			return true;
		}

		/*
		 * Static Utility Methods
		 */
		private static int ParenPairPosition (string txt, int pos)
		{
			char one = txt [pos];
			bool open = (one == '(');
			char two = (open) ? ')' : '(';

			//int level = 0;
			int num = (open) ? txt.Length - pos - 1: pos;

			int sames = 0;
			for (int i = 0; i < num; i++) {
				if (open)
					pos++;
				else
					pos--;

				if (pos < 0 || pos > txt.Length - 1)
					return -1;

				if (txt [pos] == one)
					sames++;
				else if (txt [pos] == two) {
					if (sames == 0)
						return pos;
					else
						sames--;
				}
			}

			return -1;
		}

		/*private static string ReverseString (string txt)
		{
		    char [] txt_a = txt.ToCharArray ();
		    System.Reverse (txt_a);
		    return new String (txt_a);
		}*/
	}

	public class LogicEntryCompletion : EntryCompletion {
		private Entry entry;

		private bool completing = false;
		public bool Completing {
			get { return completing; }
		}

		public LogicEntryCompletion (Entry entry, TreeModel tree_model)
		{
			this.entry = entry;

			Model = new DependentListStore(tree_model);

			InlineCompletion = false;
			MinimumKeyLength = 1;
			TextColumn = 1;
			PopupSetWidth = false;
			MatchFunc = LogicEntryCompletionMatchFunc;
			MatchSelected += HandleMatchSelected;

			// Insert these when appropriate..
			//InsertActionText (0, "or");
			//InsertActionText (1, "and");
			// HandleAction...
		}

		[GLib.ConnectBefore]
		private void HandleMatchSelected (object sender, MatchSelectedArgs args)
		{
			// Delete what the user had entered in case their casing wasn't the same
			entry.DeleteText (entry.Position - transformed_key.Length, entry.Position);

			string name = args.Model.GetValue (args.Iter, TextColumn) as string;
			//Console.WriteLine ("match selected..{0}", name);
			int pos = entry.Position;

			completing = true;
			entry.InsertText (name, ref pos);
			completing = false;

			entry.Position += name.Length;

			args.RetVal = true;
			//Console.WriteLine ("done w/ match selected");
		}

		string last_key = String.Empty;
		string transformed_key = String.Empty;
		public bool LogicEntryCompletionMatchFunc (EntryCompletion completion, string key, TreeIter iter)
		{
			if (Completing)
				return false;

			// If this is the fist comparison for this key, convert the key (which is the entire search string)
			// into just the part that is relevant to completing this tag name.
			if (key != last_key) {
				last_key = key;

				int pos = entry.Position - 1;
				if (key == null || key.Length == 0 || pos < 0 || pos > key.Length - 1)
					transformed_key = String.Empty;
				else if (key [pos] == '(' || key [pos] == ')' || key [pos] == ',')
					transformed_key = String.Empty;
				else {
					int start = 0;
					for (int i = entry.Position - 1; i >= 0; i--) {
						if (key [i] == ' ' || key [i] == ')' || key [i] == '(') {
							//Console.WriteLine ("have start break char at {0}", i);
							start = i + 1;
							break;
						}
					}

					int end = key.Length - 1;
					for (int j = entry.Position - 1; j < key.Length; j++) {
						if (key [j] == ' ' || key [j] == ')' || key [j] == '(') {
							end = j - 1;
							break;
						}
					}

					//Console.WriteLine ("start = {0} end = {1}", start, end);

					int len = end - start + 1;
					if (len > 0 && start < last_key.Length)
						transformed_key = last_key.Substring (start, end - start + 1);
					else
						transformed_key = String.Empty;
				}
				//Console.WriteLine ("transformed key {0} into {1}", key, transformed_key);
			}

			if (transformed_key == String.Empty)
				return false;

			string name = completion.Model.GetValue (iter, completion.TextColumn) as string;

			// Ignore null or names that are too short
			if (name == null || name.Length <= transformed_key.Length)
				return false;

			//Console.WriteLine ("entered = {0} compared to {1}", transformed_key, name);
			return (String.Compare (transformed_key, name.Substring(0, transformed_key.Length), true) == 0);
		}
	}
}