/* ***** BEGIN LICENSE BLOCK *****
 * Distributed under the BSD license:
 *
 * Copyright (c) 2010, Ajax.org B.V.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of Ajax.org B.V. nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL AJAX.ORG B.V. BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * ***** END LICENSE BLOCK ***** */

define(function(require, exports, module) {
"use strict";
var oop = require("./lib/oop");
var EventEmitter = require("./lib/event_emitter").EventEmitter;
var lang = require("./lib/lang");
var Range = require("./range").Range;
var Anchor = require("./anchor").Anchor;
var HashHandler = require("./keyboard/hash_handler").HashHandler;
var Tokenizer = require("./tokenizer").Tokenizer;
var comparePoints = Range.comparePoints;

var SnippetManager = function() {
    this.snippetMap = {};
    this.snippetNameMap = {};
};

(function() {
    oop.implement(this, EventEmitter);
    
    this.getTokenizer = function() {
        function TabstopToken(str, _, stack) {
            str = str.substr(1);
            if (/^\d+$/.test(str) && !stack.inFormatString)
                return [{tabstopId: parseInt(str, 10)}];
            return [{text: str}];
        }
        function escape(ch) {
            return "(?:[^\\\\" + ch + "]|\\\\.)";
        }
        SnippetManager.$tokenizer = new Tokenizer({
            start: [
                {regex: /:/, onMatch: function(val, state, stack) {
                    if (stack.length && stack[0].expectIf) {
                        stack[0].expectIf = false;
                        stack[0].elseBranch = stack[0];
                        return [stack[0]];
                    }
                    return ":";
                }},
                {regex: /\\./, onMatch: function(val, state, stack) {
                    var ch = val[1];
                    if (ch == "}" && stack.length) {
                        val = ch;
                    }else if ("`$\\".indexOf(ch) != -1) {
                        val = ch;
                    } else if (stack.inFormatString) {
                        if (ch == "n")
                            val = "\n";
                        else if (ch == "t")
                            val = "\n";
                        else if ("ulULE".indexOf(ch) != -1) {
                            val = {changeCase: ch, local: ch > "a"};
                        }
                    }

                    return [val];
                }},
                {regex: /}/, onMatch: function(val, state, stack) {
                    return [stack.length ? stack.shift() : val];
                }},
                {regex: /\$(?:\d+|\w+)/, onMatch: TabstopToken},
                {regex: /\$\{[\dA-Z_a-z]+/, onMatch: function(str, state, stack) {
                    var t = TabstopToken(str.substr(1), state, stack);
                    stack.unshift(t[0]);
                    return t;
                }, next: "snippetVar"},
                {regex: /\n/, token: "newline", merge: false}
            ],
            snippetVar: [
                {regex: "\\|" + escape("\\|") + "*\\|", onMatch: function(val, state, stack) {
                    stack[0].choices = val.slice(1, -1).split(",");
                }, next: "start"},
                {regex: "/(" + escape("/") + "+)/(?:(" + escape("/") + "*)/)(\\w*):?",
                 onMatch: function(val, state, stack) {
                    var ts = stack[0];
                    ts.fmtString = val;

                    val = this.splitRegex.exec(val);
                    ts.guard = val[1];
                    ts.fmt = val[2];
                    ts.flag = val[3];
                    return "";
                }, next: "start"},
                {regex: "`" + escape("`") + "*`", onMatch: function(val, state, stack) {
                    stack[0].code = val.splice(1, -1);
                    return "";
                }, next: "start"},
                {regex: "\\?", onMatch: function(val, state, stack) {
                    if (stack[0])
                        stack[0].expectIf = true;
                }, next: "start"},
                {regex: "([^:}\\\\]|\\\\.)*:?", token: "", next: "start"}
            ],
            formatString: [
                {regex: "/(" + escape("/") + "+)/", token: "regex"},
                {regex: "", onMatch: function(val, state, stack) {
                    stack.inFormatString = true;
                }, next: "start"}
            ]
        });
        SnippetManager.prototype.getTokenizer = function() {
            return SnippetManager.$tokenizer;
        };
        return SnippetManager.$tokenizer;
    };

    this.tokenizeTmSnippet = function(str, startState) {
        return this.getTokenizer().getLineTokens(str, startState).tokens.map(function(x) {
            return x.value || x;
        });
    };

    this.$getDefaultValue = function(editor, name) {
        if (/^[A-Z]\d+$/.test(name)) {
            var i = name.substr(1);
            return (this.variables[name[0] + "__"] || {})[i];
        }
        if (/^\d+$/.test(name)) {
            return (this.variables.__ || {})[name];
        }
        name = name.replace(/^TM_/, "");

        if (!editor)
            return;
        var s = editor.session;
        switch(name) {
            case "CURRENT_WORD":
                var r = s.getWordRange(); 
                /* falls through */
            case "SELECTION":
            case "SELECTED_TEXT":
                return s.getTextRange(r);
            case "CURRENT_LINE":
                return s.getLine(editor.getCursorPosition().row);
            case "PREV_LINE": // not possible in textmate
                return s.getLine(editor.getCursorPosition().row - 1);
            case "LINE_INDEX":
                return editor.getCursorPosition().column;
            case "LINE_NUMBER":
                return editor.getCursorPosition().row + 1;
            case "SOFT_TABS":
                return s.getUseSoftTabs() ? "YES" : "NO";
            case "TAB_SIZE":
                return s.getTabSize();
            // default but can't fill :(
            case "FILENAME":
            case "FILEPATH":
                return "";
            case "FULLNAME":
                return "Ace";
        }
    };
    this.variables = {};
    this.getVariableValue = function(editor, varName) {
        if (this.variables.hasOwnProperty(varName))
            return this.variables[varName](editor, varName) || "";
        return this.$getDefaultValue(editor, varName) || "";
    };

    // returns string formatted according to http://manual.macromates.com/en/regular_expressions#replacement_string_syntax_format_strings
    this.tmStrFormat = function(str, ch, editor) {
        var flag = ch.flag || "";
        var re = ch.guard;
        re = new RegExp(re, flag.replace(/[^gi]/, ""));
        var fmtTokens = this.tokenizeTmSnippet(ch.fmt, "formatString");
        var _self = this;
        var formatted = str.replace(re, function() {
            _self.variables.__ = arguments;
            var fmtParts = _self.resolveVariables(fmtTokens, editor);
            var gChangeCase = "E";
            for (var i  = 0; i < fmtParts.length; i++) {
                var ch = fmtParts[i];
                if (typeof ch == "object") {
                    fmtParts[i] = "";
                    if (ch.changeCase && ch.local) {
                        var next = fmtParts[i + 1];
                        if (next && typeof next == "string") {
                            if (ch.changeCase == "u")
                                fmtParts[i] = next[0].toUpperCase();
                            else
                                fmtParts[i] = next[0].toLowerCase();
                            fmtParts[i + 1] = next.substr(1);
                        }
                    } else if (ch.changeCase) {
                        gChangeCase = ch.changeCase;
                    }
                } else if (gChangeCase == "U") {
                    fmtParts[i] = ch.toUpperCase();
                } else if (gChangeCase == "L") {
                    fmtParts[i] = ch.toLowerCase();
                }
            }
            return fmtParts.join("");
        });
        this.variables.__ = null;
        return formatted;
    };

    this.resolveVariables = function(snippet, editor) {
        var result = [];
        for (var i = 0; i < snippet.length; i++) {
            var ch = snippet[i];
            if (typeof ch == "string") {
                result.push(ch);
            } else if (typeof ch != "object") {
                continue;
            } else if (ch.skip) {
                gotoNext(ch);
            } else if (ch.processed < i) {
                continue;
            } else if (ch.text) {
                var value = this.getVariableValue(editor, ch.text);
                if (value && ch.fmtString)
                    value = this.tmStrFormat(value, ch);
                ch.processed = i;
                if (ch.expectIf == null) {
                    if (value) {
                        result.push(value);
                        gotoNext(ch);
                    }
                } else {
                    if (value) {
                        ch.skip = ch.elseBranch;
                    } else
                        gotoNext(ch);
                }
            } else if (ch.tabstopId != null) {
                result.push(ch);
            } else if (ch.changeCase != null) {
                result.push(ch);
            }
        }
        function gotoNext(ch) {
            var i1 = snippet.indexOf(ch, i + 1);
            if (i1 != -1)
                i = i1;
        }
        return result;
    };

    this.insertSnippetForSelection = function(editor, snippetText) {
        var cursor = editor.getCursorPosition();
        var line = editor.session.getLine(cursor.row);
        var tabString = editor.session.getTabString();
        var indentString = line.match(/^\s*/)[0];
        
        if (cursor.column < indentString.length)
            indentString = indentString.slice(0, cursor.column);

        snippetText = snippetText.replace(/\r/g, "");
        var tokens = this.tokenizeTmSnippet(snippetText);
        tokens = this.resolveVariables(tokens, editor);
        // indent
        tokens = tokens.map(function(x) {
            if (x == "\n")
                return x + indentString;
            if (typeof x == "string")
                return x.replace(/\t/g, tabString);
            return x;
        });
        // tabstop values
        var tabstops = [];
        tokens.forEach(function(p, i) {
            if (typeof p != "object")
                return;
            var id = p.tabstopId;
            var ts = tabstops[id];
            if (!ts) {
                ts = tabstops[id] = [];
                ts.index = id;
                ts.value = "";
            }
            if (ts.indexOf(p) !== -1)
                return;
            ts.push(p);
            var i1 = tokens.indexOf(p, i + 1);
            if (i1 === -1)
                return;

            var value = tokens.slice(i + 1, i1);
            var isNested = value.some(function(t) {return typeof t === "object";});
            if (isNested && !ts.value) {
                ts.value = value;
            } else if (value.length && (!ts.value || typeof ts.value !== "string")) {
                ts.value = value.join("");
            }
        });

        // expand tabstop values
        tabstops.forEach(function(ts) {ts.length = 0;});
        var expanding = {};
        function copyValue(val) {
            var copy = [];
            for (var i = 0; i < val.length; i++) {
                var p = val[i];
                if (typeof p == "object") {
                    if (expanding[p.tabstopId])
                        continue;
                    var j = val.lastIndexOf(p, i - 1);
                    p = copy[j] || {tabstopId: p.tabstopId};
                }
                copy[i] = p;
            }
            return copy;
        }
        for (var i = 0; i < tokens.length; i++) {
            var p = tokens[i];
            if (typeof p != "object")
                continue;
            var id = p.tabstopId;
            var i1 = tokens.indexOf(p, i + 1);
            if (expanding[id]) {
                // if reached closing bracket clear expanding state
                if (expanding[id] === p)
                    expanding[id] = null;
                // otherwise just ignore recursive tabstop
                continue;
            }
            
            var ts = tabstops[id];
            var arg = typeof ts.value == "string" ? [ts.value] : copyValue(ts.value);
            arg.unshift(i + 1, Math.max(0, i1 - i));
            arg.push(p);
            expanding[id] = p;
            tokens.splice.apply(tokens, arg);

            if (ts.indexOf(p) === -1)
                ts.push(p);
        }
        
        // convert to plain text
        var row = 0, column = 0;
        var text = "";
        tokens.forEach(function(t) {
            if (typeof t === "string") {
                var lines = t.split("\n");
                if (lines.length > 1){
                    column = lines[lines.length - 1].length;
                    row += lines.length - 1;
                } else
                    column += t.length;
                text += t;
            } else {
                if (!t.start)
                    t.start = {row: row, column: column};
                else
                    t.end = {row: row, column: column};
            }
        });
        var range = editor.getSelectionRange();
        var end = editor.session.replace(range, text);

        var tabstopManager = new TabstopManager(editor);
        var selectionId = editor.inVirtualSelectionMode && editor.selection.index;
        tabstopManager.addTabstops(tabstops, range.start, end, selectionId);
    };
    
    this.insertSnippet = function(editor, snippetText) {
        var self = this;
        if (editor.inVirtualSelectionMode)
            return self.insertSnippetForSelection(editor, snippetText);
        
        editor.forEachSelection(function() {
            self.insertSnippetForSelection(editor, snippetText);
        }, null, {keepOrder: true});
        
        if (editor.tabstopManager)
            editor.tabstopManager.tabNext();
    };

    this.$getScope = function(editor) {
        var scope = editor.session.$mode.$id || "";
        scope = scope.split("/").pop();
        if (scope === "html" || scope === "php") {
            // PHP is actually HTML
            if (scope === "php" && !editor.session.$mode.inlinePhp) 
                scope = "html";
            var c = editor.getCursorPosition();
            var state = editor.session.getState(c.row);
            if (typeof state === "object") {
                state = state[0];
            }
            if (state.substring) {
                if (state.substring(0, 3) == "js-")
                    scope = "javascript";
                else if (state.substring(0, 4) == "css-")
                    scope = "css";
                else if (state.substring(0, 4) == "php-")
                    scope = "php";
            }
        }
        
        return scope;
    };

    this.getActiveScopes = function(editor) {
        var scope = this.$getScope(editor);
        var scopes = [scope];
        var snippetMap = this.snippetMap;
        if (snippetMap[scope] && snippetMap[scope].includeScopes) {
            scopes.push.apply(scopes, snippetMap[scope].includeScopes);
        }
        scopes.push("_");
        return scopes;
    };

    this.expandWithTab = function(editor, options) {
        var self = this;
        var result = editor.forEachSelection(function() {
            return self.expandSnippetForSelection(editor, options);
        }, null, {keepOrder: true});
        if (result && editor.tabstopManager)
            editor.tabstopManager.tabNext();
        return result;
    };
    
    this.expandSnippetForSelection = function(editor, options) {
        var cursor = editor.getCursorPosition();
        var line = editor.session.getLine(cursor.row);
        var before = line.substring(0, cursor.column);
        var after = line.substr(cursor.column);

        var snippetMap = this.snippetMap;
        var snippet;
        this.getActiveScopes(editor).some(function(scope) {
            var snippets = snippetMap[scope];
            if (snippets)
                snippet = this.findMatchingSnippet(snippets, before, after);
            return !!snippet;
        }, this);
        if (!snippet)
            return false;
        if (options && options.dryRun)
            return true;
        editor.session.doc.removeInLine(cursor.row,
            cursor.column - snippet.replaceBefore.length,
            cursor.column + snippet.replaceAfter.length
        );

        this.variables.M__ = snippet.matchBefore;
        this.variables.T__ = snippet.matchAfter;
        this.insertSnippetForSelection(editor, snippet.content);

        this.variables.M__ = this.variables.T__ = null;
        return true;
    };

    this.findMatchingSnippet = function(snippetList, before, after) {
        for (var i = snippetList.length; i--;) {
            var s = snippetList[i];
            if (s.startRe && !s.startRe.test(before))
                continue;
            if (s.endRe && !s.endRe.test(after))
                continue;
            if (!s.startRe && !s.endRe)
                continue;

            s.matchBefore = s.startRe ? s.startRe.exec(before) : [""];
            s.matchAfter = s.endRe ? s.endRe.exec(after) : [""];
            s.replaceBefore = s.triggerRe ? s.triggerRe.exec(before)[0] : "";
            s.replaceAfter = s.endTriggerRe ? s.endTriggerRe.exec(after)[0] : "";
            return s;
        }
    };

    this.snippetMap = {};
    this.snippetNameMap = {};
    this.register = function(snippets, scope) {
        var snippetMap = this.snippetMap;
        var snippetNameMap = this.snippetNameMap;
        var self = this;
        
        if (!snippets) 
            snippets = [];
        
        function wrapRegexp(src) {
            if (src && !/^\^?\(.*\)\$?$|^\\b$/.test(src))
                src = "(?:" + src + ")";

            return src || "";
        }
        function guardedRegexp(re, guard, opening) {
            re = wrapRegexp(re);
            guard = wrapRegexp(guard);
            if (opening) {
                re = guard + re;
                if (re && re[re.length - 1] != "$")
                    re = re + "$";
            } else {
                re = re + guard;
                if (re && re[0] != "^")
                    re = "^" + re;
            }
            return new RegExp(re);
        }

        function addSnippet(s) {
            if (!s.scope)
                s.scope = scope || "_";
            scope = s.scope;
            if (!snippetMap[scope]) {
                snippetMap[scope] = [];
                snippetNameMap[scope] = {};
            }

            var map = snippetNameMap[scope];
            if (s.name) {
                var old = map[s.name];
                if (old)
                    self.unregister(old);
                map[s.name] = s;
            }
            snippetMap[scope].push(s);

            if (s.tabTrigger && !s.trigger) {
                if (!s.guard && /^\w/.test(s.tabTrigger))
                    s.guard = "\\b";
                s.trigger = lang.escapeRegExp(s.tabTrigger);
            }
            
            if (!s.trigger && !s.guard && !s.endTrigger && !s.endGuard)
                return;
            
            s.startRe = guardedRegexp(s.trigger, s.guard, true);
            s.triggerRe = new RegExp(s.trigger);

            s.endRe = guardedRegexp(s.endTrigger, s.endGuard, true);
            s.endTriggerRe = new RegExp(s.endTrigger);
        }

        if (snippets && snippets.content)
            addSnippet(snippets);
        else if (Array.isArray(snippets))
            snippets.forEach(addSnippet);
        
        this._signal("registerSnippets", {scope: scope});
    };
    this.unregister = function(snippets, scope) {
        var snippetMap = this.snippetMap;
        var snippetNameMap = this.snippetNameMap;

        function removeSnippet(s) {
            var nameMap = snippetNameMap[s.scope||scope];
            if (nameMap && nameMap[s.name]) {
                delete nameMap[s.name];
                var map = snippetMap[s.scope||scope];
                var i = map && map.indexOf(s);
                if (i >= 0)
                    map.splice(i, 1);
            }
        }
        if (snippets.content)
            removeSnippet(snippets);
        else if (Array.isArray(snippets))
            snippets.forEach(removeSnippet);
    };
    this.parseSnippetFile = function(str) {
        str = str.replace(/\r/g, "");
        var list = [], snippet = {};
        var re = /^#.*|^({[\s\S]*})\s*$|^(\S+) (.*)$|^((?:\n*\t.*)+)/gm;
        var m;
        while (m = re.exec(str)) {
            if (m[1]) {
                try {
                    snippet = JSON.parse(m[1]);
                    list.push(snippet);
                } catch (e) {}
            } if (m[4]) {
                snippet.content = m[4].replace(/^\t/gm, "");
                list.push(snippet);
                snippet = {};
            } else {
                var key = m[2], val = m[3];
                if (key == "regex") {
                    var guardRe = /\/((?:[^\/\\]|\\.)*)|$/g;
                    snippet.guard = guardRe.exec(val)[1];
                    snippet.trigger = guardRe.exec(val)[1];
                    snippet.endTrigger = guardRe.exec(val)[1];
                    snippet.endGuard = guardRe.exec(val)[1];
                } else if (key == "snippet") {
                    snippet.tabTrigger = val.match(/^\S*/)[0];
                    if (!snippet.name)
                        snippet.name = val;
                } else {
                    snippet[key] = val;
                }
            }
        }
        return list;
    };
    this.getSnippetByName = function(name, editor) {
        var snippetMap = this.snippetNameMap;
        var snippet;
        this.getActiveScopes(editor).some(function(scope) {
            var snippets = snippetMap[scope];
            if (snippets)
                snippet = snippets[name];
            return !!snippet;
        }, this);
        return snippet;
    };

}).call(SnippetManager.prototype);


var TabstopManager = function(editor) {
    if (editor.tabstopManager)
        return editor.tabstopManager;
    editor.tabstopManager = this;
    this.$onChange = this.onChange.bind(this);
    this.$onChangeSelection = lang.delayedCall(this.onChangeSelection.bind(this)).schedule;
    this.$onChangeSession = this.onChangeSession.bind(this);
    this.$onAfterExec = this.onAfterExec.bind(this);
    this.attach(editor);
};
(function() {
    this.attach = function(editor) {
        this.index = 0;
        this.ranges = [];
        this.tabstops = [];
        this.$openTabstops = null;
        this.selectedTabstop = null;

        this.editor = editor;
        this.editor.on("change", this.$onChange);
        this.editor.on("changeSelection", this.$onChangeSelection);
        this.editor.on("changeSession", this.$onChangeSession);
        this.editor.commands.on("afterExec", this.$onAfterExec);
        this.editor.keyBinding.addKeyboardHandler(this.keyboardHandler);
    };
    this.detach = function() {
        this.tabstops.forEach(this.removeTabstopMarkers, this);
        this.ranges = null;
        this.tabstops = null;
        this.selectedTabstop = null;
        this.editor.removeListener("change", this.$onChange);
        this.editor.removeListener("changeSelection", this.$onChangeSelection);
        this.editor.removeListener("changeSession", this.$onChangeSession);
        this.editor.commands.removeListener("afterExec", this.$onAfterExec);
        this.editor.keyBinding.removeKeyboardHandler(this.keyboardHandler);
        this.editor.tabstopManager = null;
        this.editor = null;
    };

    this.onChange = function(delta) {
        var changeRange = delta;
        var isRemove = delta.action[0] == "r";
        var start = delta.start;
        var end = delta.end;
        var startRow = start.row;
        var endRow = end.row;
        var lineDif = endRow - startRow;
        var colDiff = end.column - start.column;

        if (isRemove) {
            lineDif = -lineDif;
            colDiff = -colDiff;
        }
        if (!this.$inChange && isRemove) {
            var ts = this.selectedTabstop;
            var changedOutside = ts && !ts.some(function(r) {
                return comparePoints(r.start, start) <= 0 && comparePoints(r.end, end) >= 0;
            });
            if (changedOutside)
                return this.detach();
        }
        var ranges = this.ranges;
        for (var i = 0; i < ranges.length; i++) {
            var r = ranges[i];
            if (r.end.row < start.row)
                continue;

            if (isRemove && comparePoints(start, r.start) < 0 && comparePoints(end, r.end) > 0) {
                this.removeRange(r);
                i--;
                continue;
            }

            if (r.start.row == startRow && r.start.column > start.column)
                r.start.column += colDiff;
            if (r.end.row == startRow && r.end.column >= start.column)
                r.end.column += colDiff;
            if (r.start.row >= startRow)
                r.start.row += lineDif;
            if (r.end.row >= startRow)
                r.end.row += lineDif;

            if (comparePoints(r.start, r.end) > 0)
                this.removeRange(r);
        }
        if (!ranges.length)
            this.detach();
    };
    this.updateLinkedFields = function() {
        var ts = this.selectedTabstop;
        if (!ts || !ts.hasLinkedRanges)
            return;
        this.$inChange = true;
        var session = this.editor.session;
        var text = session.getTextRange(ts.firstNonLinked);
        for (var i = ts.length; i--;) {
            var range = ts[i];
            if (!range.linked)
                continue;
            var fmt = exports.snippetManager.tmStrFormat(text, range.original);
            session.replace(range, fmt);
        }
        this.$inChange = false;
    };
    this.onAfterExec = function(e) {
        if (e.command && !e.command.readOnly)
            this.updateLinkedFields();
    };
    this.onChangeSelection = function() {
        if (!this.editor)
            return;
        var lead = this.editor.selection.lead;
        var anchor = this.editor.selection.anchor;
        var isEmpty = this.editor.selection.isEmpty();
        for (var i = this.ranges.length; i--;) {
            if (this.ranges[i].linked)
                continue;
            var containsLead = this.ranges[i].contains(lead.row, lead.column);
            var containsAnchor = isEmpty || this.ranges[i].contains(anchor.row, anchor.column);
            if (containsLead && containsAnchor)
                return;
        }
        this.detach();
    };
    this.onChangeSession = function() {
        this.detach();
    };
    this.tabNext = function(dir) {
        var max = this.tabstops.length;
        var index = this.index + (dir || 1);
        index = Math.min(Math.max(index, 1), max);
        if (index == max)
            index = 0;
        this.selectTabstop(index);
        if (index === 0)
            this.detach();
    };
    this.selectTabstop = function(index) {
        this.$openTabstops = null;
        var ts = this.tabstops[this.index];
        if (ts)
            this.addTabstopMarkers(ts);
        this.index = index;
        ts = this.tabstops[this.index];
        if (!ts || !ts.length)
            return;
        
        this.selectedTabstop = ts;
        if (!this.editor.inVirtualSelectionMode) {        
            var sel = this.editor.multiSelect;
            sel.toSingleRange(ts.firstNonLinked.clone());
            for (var i = ts.length; i--;) {
                if (ts.hasLinkedRanges && ts[i].linked)
                    continue;
                sel.addRange(ts[i].clone(), true);
            }
            // todo investigate why is this needed
            if (sel.ranges[0])
                sel.addRange(sel.ranges[0].clone());
        } else {
            this.editor.selection.setRange(ts.firstNonLinked);
        }
        
        this.editor.keyBinding.addKeyboardHandler(this.keyboardHandler);
    };
    this.addTabstops = function(tabstops, start, end) {
        if (!this.$openTabstops)
            this.$openTabstops = [];
        // add final tabstop if missing
        if (!tabstops[0]) {
            var p = Range.fromPoints(end, end);
            moveRelative(p.start, start);
            moveRelative(p.end, start);
            tabstops[0] = [p];
            tabstops[0].index = 0;
        }

        var i = this.index;
        var arg = [i + 1, 0];
        var ranges = this.ranges;
        tabstops.forEach(function(ts, index) {
            var dest = this.$openTabstops[index] || ts;
                
            for (var i = ts.length; i--;) {
                var p = ts[i];
                var range = Range.fromPoints(p.start, p.end || p.start);
                movePoint(range.start, start);
                movePoint(range.end, start);
                range.original = p;
                range.tabstop = dest;
                ranges.push(range);
                if (dest != ts)
                    dest.unshift(range);
                else
                    dest[i] = range;
                if (p.fmtString) {
                    range.linked = true;
                    dest.hasLinkedRanges = true;
                } else if (!dest.firstNonLinked)
                    dest.firstNonLinked = range;
            }
            if (!dest.firstNonLinked)
                dest.hasLinkedRanges = false;
            if (dest === ts) {
                arg.push(dest);
                this.$openTabstops[index] = dest;
            }
            this.addTabstopMarkers(dest);
        }, this);
        
        if (arg.length > 2) {
            // when adding new snippet inside existing one, make sure 0 tabstop is at the end
            if (this.tabstops.length)
                arg.push(arg.splice(2, 1)[0]);
            this.tabstops.splice.apply(this.tabstops, arg);
        }
    };

    this.addTabstopMarkers = function(ts) {
        var session = this.editor.session;
        ts.forEach(function(range) {
            if  (!range.markerId)
                range.markerId = session.addMarker(range, "ace_snippet-marker", "text");
        });
    };
    this.removeTabstopMarkers = function(ts) {
        var session = this.editor.session;
        ts.forEach(function(range) {
            session.removeMarker(range.markerId);
            range.markerId = null;
        });
    };
    this.removeRange = function(range) {
        var i = range.tabstop.indexOf(range);
        range.tabstop.splice(i, 1);
        i = this.ranges.indexOf(range);
        this.ranges.splice(i, 1);
        this.editor.session.removeMarker(range.markerId);
        if (!range.tabstop.length) {
            i = this.tabstops.indexOf(range.tabstop);
            if (i != -1)
                this.tabstops.splice(i, 1);
            if (!this.tabstops.length)
                this.detach();
        }
    };

    this.keyboardHandler = new HashHandler();
    this.keyboardHandler.bindKeys({
        "Tab": function(ed) {
            if (exports.snippetManager && exports.snippetManager.expandWithTab(ed)) {
                return;
            }

            ed.tabstopManager.tabNext(1);
        },
        "Shift-Tab": function(ed) {
            ed.tabstopManager.tabNext(-1);
        },
        "Esc": function(ed) {
            ed.tabstopManager.detach();
        },
        "Return": function(ed) {
            //ed.tabstopManager.tabNext(1);
            return false;
        }
    });
}).call(TabstopManager.prototype);



var changeTracker = {};
changeTracker.onChange = Anchor.prototype.onChange;
changeTracker.setPosition = function(row, column) {
    this.pos.row = row;
    this.pos.column = column;
};
changeTracker.update = function(pos, delta, $insertRight) {
    this.$insertRight = $insertRight;
    this.pos = pos; 
    this.onChange(delta);
};

var movePoint = function(point, diff) {
    if (point.row == 0)
        point.column += diff.column;
    point.row += diff.row;
};

var moveRelative = function(point, start) {
    if (point.row == start.row)
        point.column -= start.column;
    point.row -= start.row;
};


require("./lib/dom").importCssString("\
.ace_snippet-marker {\
    -moz-box-sizing: border-box;\
    box-sizing: border-box;\
    background: rgba(194, 193, 208, 0.09);\
    border: 1px dotted rgba(211, 208, 235, 0.62);\
    position: absolute;\
}");

exports.snippetManager = new SnippetManager();


var Editor = require("./editor").Editor;
(function() {
    this.insertSnippet = function(content, options) {
        return exports.snippetManager.insertSnippet(this, content, options);
    };
    this.expandSnippet = function(options) {
        return exports.snippetManager.expandWithTab(this, options);
    };
}).call(Editor.prototype);

});