/*Copyright (C) 2015 by Marijn Haverbeke <marijnh@gmail.com> and others

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.*/

    (function(mod) {
    if (typeof exports == "object" && typeof module == "object") // CommonJS
        mod(require("codemirror"), require("sql"));
    else if (typeof define == "function" && define.amd) // AMD
        define(["codemirror", "sql"], mod);
    else // Plain browser env
        mod(CodeMirror);
})(function(CodeMirror) {
    "use strict";

    var tables;
    var defaultTable;
    var keywords;
    var CONS = {
        QUERY_DIV: ";",
        ALIAS_KEYWORD: "AS"
    };
    var Pos = CodeMirror.Pos;

    function getKeywords(editor) {
        var mode = editor.doc.modeOption;
        if (mode === "sql") mode = MIME_TYPE_SIDDHI_QL;
        return CodeMirror.resolveMode(mode).allSqlSuggestions;
    }

    function getText(item) {
        return typeof item == "string" ? item : item.text;
    }

    function getItem(list, item) {
        if (!list.slice) return list[item];
        for (var i = list.length - 1; i >= 0; i--) if (getText(list[i]) == item)
            return list[i];
    }

    function shallowClone(object) {
        var result = {};
        for (var key in object) if (object.hasOwnProperty(key))
            result[key] = object[key];
        return result;
    }

    function match(string, word) {
        var len = string.length;
        var sub = getText(word).substr(0, len);
        return string.toUpperCase() === sub.toUpperCase();
    }

    function addMatches(result, search, wordlist, formatter) {
        for (var word in wordlist) {
            if (!wordlist.hasOwnProperty(word)) continue;
            if (wordlist.slice) word = wordlist[word];

            if (match(search, word)) result.push(formatter(word));
        }
    }

    function cleanName(name) {
        // Get rid name from backticks(`) and preceding dot(.)
        if (name.charAt(0) == ".") {
            name = name.substr(1);
        }
        return name.replace(/`/g, "");
    }

    function insertBackticks(name) {
        var nameParts = getText(name).split(".");
        for (var i = 0; i < nameParts.length; i++)
            nameParts[i] = "`" + nameParts[i] + "`";
        var escaped = nameParts.join(".");
        if (typeof name == "string") return escaped;
        name = shallowClone(name);
        name.text = escaped;
        return name;
    }

    function nameCompletion(cur, token, result, editor) {
        // Try to complete table, colunm names and return start position of completion
        var useBacktick = false;
        var nameParts = [];
        var start = token.start;
        var cont = true;
        while (cont) {
            cont = (token.string.charAt(0) == ".");
            useBacktick = useBacktick || (token.string.charAt(0) == "`");

            start = token.start;
            nameParts.unshift(cleanName(token.string));

            token = editor.getTokenAt(Pos(cur.line, token.start));
            if (token.string == ".") {
                cont = true;
                token = editor.getTokenAt(Pos(cur.line, token.start));
            }
        }

        // Try to complete table names
        var string = nameParts.join(".");
        addMatches(result, string, tables, function(w) {
            return useBacktick ? insertBackticks(w) : w;
        });

        // Try to complete columns from defaultTable
        addMatches(result, string, defaultTable, function(w) {
            return useBacktick ? insertBackticks(w) : w;
        });

        // Try to complete columns
        string = nameParts.pop();
        var table = nameParts.join(".");

        // Check if table is available. If not, find table by Alias
        if (!getItem(tables, table))
            table = findTableByAlias(table, editor);

        var columns = getItem(tables, table);
        if (columns && columns.columns)
            columns = columns.columns;

        if (columns) {
            addMatches(result, string, columns, function(w) {
                if (typeof w == "string") {
                    w = table + "." + w;
                } else {
                    w = shallowClone(w);
                    w.text = table + "." + w.text;
                }
                return useBacktick ? insertBackticks(w) : w;
            });
        }

        return start;
    }

    function eachWord(lineText, f) {
        if (!lineText) return;
        var excepted = /[,;]/g;
        var words = lineText.split(" ");
        for (var i = 0; i < words.length; i++) {
            f(words[i]?words[i].replace(excepted, '') : '');
        }
    }

    function convertCurToNumber(cur) {
        // max characters of a line is 999,999.
        return cur.line + cur.ch / Math.pow(10, 6);
    }

    function convertNumberToCur(num) {
        return Pos(Math.floor(num), +num.toString().split('.').pop());
    }

    function findTableByAlias(alias, editor) {
        var doc = editor.doc;
        var fullQuery = doc.getValue();
        var aliasUpperCase = alias.toUpperCase();
        var previousWord = "";
        var table = "";
        var separator = [];
        var validRange = {
            start: Pos(0, 0),
            end: Pos(editor.lastLine(), editor.getLineHandle(editor.lastLine()).length)
        };

        //add separator
        var indexOfSeparator = fullQuery.indexOf(CONS.QUERY_DIV);
        while(indexOfSeparator != -1) {
            separator.push(doc.posFromIndex(indexOfSeparator));
            indexOfSeparator = fullQuery.indexOf(CONS.QUERY_DIV, indexOfSeparator+1);
        }
        separator.unshift(Pos(0, 0));
        separator.push(Pos(editor.lastLine(), editor.getLineHandle(editor.lastLine()).text.length));

        //find valid range
        var prevItem = 0;
        var current = convertCurToNumber(editor.getCursor());
        for (var i=0; i< separator.length; i++) {
            var _v = convertCurToNumber(separator[i]);
            if (current > prevItem && current <= _v) {
                validRange = { start: convertNumberToCur(prevItem), end: convertNumberToCur(_v) };
                break;
            }
            prevItem = _v;
        }

        var query = doc.getRange(validRange.start, validRange.end, false);

        for (var i = 0; i < query.length; i++) {
            var lineText = query[i];
            eachWord(lineText, function(word) {
                var wordUpperCase = word.toUpperCase();
                if (wordUpperCase === aliasUpperCase && getItem(tables, previousWord))
                    table = previousWord;
                if (wordUpperCase !== CONS.ALIAS_KEYWORD)
                    previousWord = word;
            });
            if (table) break;
        }
        return table;
    }

    /** This helper returns both
     *      SQL suggestions (as in original sql-hint.js) and
     *      any-word suggestions (which is a customization)   */
    CodeMirror.registerHelper("hint", "sql", function(editor, options) {

        //Making the SQL suggestions list as 'sqlSuggestions'
        tables = (options && options.tables) || {};
        var defaultTableName = options && options.defaultTable;
        defaultTable = defaultTableName && getItem(tables, defaultTableName);
        keywords = keywords || getKeywords(editor);

        if (defaultTableName && !defaultTable)
            defaultTable = findTableByAlias(defaultTableName, editor);

        defaultTable = defaultTable || [];

        if (defaultTable.columns)
            defaultTable = defaultTable.columns;

        var cur = editor.getCursor();
        var sqlSuggestions = [];
        var token = editor.getTokenAt(cur), start, end, search;
        if (token.end > cur.ch) {
            token.end = cur.ch;
            token.string = token.string.slice(0, cur.ch - token.start);
        }

        if (token.string.match(/^[.`\w@]\w*$/)) {
            search = token.string;
            start = token.start;
            end = token.end;
        } else {
            start = end = cur.ch;
            search = "";
        }
        if (search.charAt(0) == "." || search.charAt(0) == "`") {
            start = nameCompletion(cur, token, sqlSuggestions, editor);
        } else {
            addMatches(sqlSuggestions, search, tables, function(w) {return w;});
            addMatches(sqlSuggestions, search, defaultTable, function(w) {return w;});
            addMatches(sqlSuggestions, search, keywords, function(w) {return w;});
        }

        var anyWordSuggestions = getAnyWordSuggestions(editor, options);

        var allSuggestions = anyWordSuggestions.concat(sqlSuggestions);
        var filteredSuggestions = allSuggestions.filter(function (item, pos, self) {
            return self.indexOf(item) == pos;
        })

        return {list: filteredSuggestions, from: Pos(cur.line, start), to: Pos(cur.line, end)};
    });
});
