//var db = require("../database");
var $util = require("../utilities");
var bcrypt = require("bcrypt");
var db = require("../database");
var Config = require("../config");

var registrationLock = {};
var blackHole = function () { };

module.exports = {
    init: function () {
    },

    /**
     * Check if a username is taken
     */
    isUsernameTaken: function (name, callback) {
        db.query("SELECT name FROM `users` WHERE name=?", [name],
        function (err, rows) {
            if (err) {
                callback(err, true);
                return;
            }
            callback(null, rows.length > 0);
        });
    },

    /**
     * Search for a user by name
     */
    search: function (name, fields, callback) {
        /* This bit allows it to accept varargs
           Function can be called as (name, callback) or
           (name, fields, callback)
        */
        if (typeof callback !== "function") {
            if (typeof fields === "function") {
                callback = fields;
                fields = ["name"];
            } else {
                return;
            }
        }

        // Don't allow search to return password hashes
        if (fields.indexOf("password") !== -1) {
            fields.splice(fields.indexOf("password"));
        }

        db.query("SELECT " + fields.join(",") + " FROM `users` WHERE name LIKE ?",
                 ["%"+name+"%"],
        function (err, rows) {
            if (err) {
                callback(err, true);
                return;
            }
            callback(null, rows);
        });
    },

    /**
     * Registers a new user account
     */
    register: function (name, pw, email, ip, callback) {
        // Start off with a boatload of error checking
        if (typeof callback !== "function") {
            callback = blackHole;
        }

        if (typeof name !== "string" || typeof pw !== "string") {
            callback("You must provide a nonempty username and password", null);
            return;
        }
        var lname = name.toLowerCase();

        if (registrationLock[lname]) {
            callback("There is already a registration in progress for "+name,
                     null);
            return;
        }

        if (!$util.isValidUserName(name)) {
            callback("Invalid username.  Usernames may consist of 1-20 " +
                     "characters a-z, A-Z, 0-9, -, _, and accented letters.",
                     null);
            return;
        }

        if (typeof email !== "string") {
            email = "";
        }

        if (typeof ip !== "string") {
            ip = "";
        }

        // From this point forward, actual registration happens
        // registrationLock prevents concurrent database activity
        // on the same user account
        registrationLock[lname] = true;

        this.getAccounts(ip, function (err, accts) {
            if (err) {
                delete registrationLock[lname];
                callback(err, null);
                return;
            }
            
            if (accts.length >= Config.get("max-accounts-per-ip")) {
                delete registrationLock[lname];
                callback("You have registered too many accounts from this "+
                         "computer.", null);
                return;
            }

            module.exports.isUsernameTaken(name, function (err, taken) {
                if (err) {
                    delete registrationLock[lname];
                    callback(err, null);
                    return;
                }

                if (taken) {
                    delete registrationLock[lname];
                    callback("Username is already registered", null);
                    return;
                }

                bcrypt.hash(pw, 10, function (err, hash) {
                    if (err) {
                        delete registrationLock[lname];
                        callback(err, null);
                        return;
                    }

                    db.query("INSERT INTO `users` " +
                             "(`name`, `password`, `global_rank`, `email`, `profile`, `ip`, `time`)" +
                             " VALUES " +
                             "(?, ?, ?, ?, '', ?, ?)",
                             [name, hash, 1, email, ip, Date.now()],
                    function (err, res) {
                        delete registrationLock[lname];
                        if (err) {
                            callback(err, null);
                        } else {
                            callback(null, {
                                name: name,
                                hash: hash
                            });
                        }
                    });
                });
            });
        });
    },

    /**
     * Verify a username/password pair
     */
    verifyLogin: function (name, pw, callback) {
        if (typeof callback !== "function") {
            return;
        }

        if (typeof name !== "string" || typeof pw !== "string") {
            callback("Invalid username/password combination", null);
            return;
        }

        /* Passwords are capped at 100 characters to prevent a potential
           denial of service vector through causing the server to hash
           ridiculously long strings.
        */
        pw = pw.substring(0, 100);

        /* Note: rather than hash the password and then query based on name and
           password, I query by name, then use bcrypt.compare() to check that
           the hashes match.
        */

        db.query("SELECT name,password,global_rank FROM `users` WHERE name=?",
                 [name],
        function (err, rows) {
            if (err) {
                callback(err, null);
                return;
            }

            if (rows.length === 0) {
                callback("User does not exist", null);
                return;
            }

            bcrypt.compare(pw, rows[0].password, function (err, match) {
                if (err) {
                    callback(err, null);
                } else if (!match) {
                    callback("Invalid username/password combination", null);
                } else {
                    callback(null, {
                        name: rows[0].name,
                        hash: rows[0].password,
                        global_rank: rows[0].global_rank
                    });
                }
            });
        });
    },

    /**
     * Verify an auth string of the form name:hash
     */
    verifyAuth: function (auth, callback) {
        if (typeof callback !== "function") {
            return;
        }

        if (typeof auth !== "string") {
            callback("Invalid auth string", null);
            return;
        }

        var split = auth.split(":");
        if (split.length !== 2) {
            callback("Invalid auth string", null);
            return;
        }

        var name = split[0];
        var hash = split[1];
        db.query("SELECT name,password,global_rank FROM `users` WHERE " +
                 "name=? and password=?", [name, hash],
        function (err, rows) {
            if (err) {
                callback(err, null);
                return;
            }

            if (rows.length === 0) {
                callback("Auth string does not match an existing user", null);
                return;
            }

            callback(null, {
                name: rows[0].name,
                hash: rows[0].password,
                global_rank: rows[0].global_rank
            });
        });
    },

    /**
     * Change a user's password
     */
    setPassword: function (name, pw, callback) {
        if (typeof callback !== "function") {
            callback = blackHole;
        }

        if (typeof name !== "string" || typeof pw !== "string") {
            callback("Invalid username/password combination", null);
            return;
        }

        /* Passwords are capped at 100 characters to prevent a potential
           denial of service vector through causing the server to hash
           ridiculously long strings.
        */
        pw = pw.substring(0, 100);

        bcrypt.hash(pw, 10, function (err, hash) {
            if (err) {
                callback(err, null);
                return;
            }

            db.query("UPDATE `users` SET password=? WHERE name=?",
                     [hash, name],
            function (err, result) {
                callback(err, err ? null : true);
            });
        });
    },

    /**
     * Lookup a user's global rank
     */
    getGlobalRank: function (name, callback) {
        if (typeof callback !== "function") {
            return;
        }

        if (typeof name !== "string") {
            callback("Invalid username", null);
            return;
        }

        if (!name) {
            callback(null, -1);
            return;
        }

        db.query("SELECT global_rank FROM `users` WHERE name=?", [name],
        function (err, rows) {
            if (err) {
                callback(err, null);
            } else if (rows.length === 0) {
                callback(null, 0);
            } else {
                callback(null, rows[0].global_rank);
            }
        });
    },

    /**
     * Updates a user's global rank
     */
    setGlobalRank: function (name, rank, callback) {
        if (typeof callback !== "function") {
            callback = blackHole;
        }

        if (typeof name !== "string") {
            callback("Invalid username", null);
            return;
        }

        if (typeof rank !== "number") {
            callback("Invalid rank", null);
            return;
        }

        db.query("UPDATE `users` SET global_rank=? WHERE name=?", [rank, name],
        function (err, result) {
            callback(err, err ? null : true);
        });
    },

    /**
     * Lookup multiple users' global rank in one query
     */
    getGlobalRanks: function (names, callback) {
        if (typeof callback !== "function") {
            return;
        }

        if (!(names instanceof Array)) {
            callback("Expected array of names, got " + typeof names, null);
            return;
        }

        if (names.length === 0) {
            return callback(null, []);
        }

        var list = "(" + names.map(function () { return "?";}).join(",") + ")";

        db.query("SELECT global_rank FROM `users` WHERE name IN " + list, names,
        function (err, rows) {
            if (err) {
                callback(err, null);
            } else if (rows.length === 0) {
                callback(null, []);
            } else {
                callback(null, rows.map(function (x) { return x.global_rank; }));
            }
        });
    },

    /**
     * Lookup a user's email
     */
    getEmail: function (name, callback) {
        if (typeof callback !== "function") {
            return;
        }

        if (typeof name !== "string") {
            callback("Invalid username", null);
            return;
        }

        db.query("SELECT email FROM `users` WHERE name=?", [name],
        function (err, rows) {
            if (err) {
                callback(err, null);
            } else if (rows.length === 0) {
                callback("User does not exist", null);
            } else {
                callback(null, rows[0].email);
            }
        });
    },

    /**
     * Updates a user's email
     */
    setEmail: function (name, email, callback) {
        if (typeof callback !== "function") {
            callback = blackHole;
        }

        if (typeof name !== "string") {
            callback("Invalid username", null);
            return;
        }

        if (typeof email !== "string") {
            callback("Invalid email", null);
            return;
        }

        db.query("UPDATE `users` SET email=? WHERE name=?", [email, name],
        function (err, result) {
            callback(err, err ? null : true);
        });
    },

    /**
     * Lookup a user's profile
     */
    getProfile: function (name, callback) {
        if (typeof callback !== "function") {
            return;
        }

        if (typeof name !== "string") {
            callback("Invalid username", null);
            return;
        }

        db.query("SELECT profile FROM `users` WHERE name=?", [name],
        function (err, rows) {
            if (err) {
                callback(err, null);
            } else if (rows.length === 0) {
                callback("User does not exist", null);
            } else {
                var userprof = {
                    image: "",
                    text: ""
                };

                if (rows[0].profile === "") {
                    callback(null, userprof);
                    return;
                }

                try {
                    var profile = JSON.parse(rows[0].profile);
                    userprof.image = profile.image || "";
                    userprof.text = profile.text || "";
                    callback(null, userprof);
                } catch (e) {
                    callback(e, null);
                }
            }
        });
    },

    /**
     * Updates a user's profile
     */
    setProfile: function (name, profile, callback) {
        if (typeof callback !== "function") {
            callback = blackHole;
        }

        if (typeof name !== "string") {
            callback("Invalid username", null);
            return;
        }

        if (typeof profile !== "object") {
            callback("Invalid profile", null);
            return;
        }

        // Cast to string to guarantee string type
        profile.image += "";
        profile.text += "";

        // Limit size
        profile.image = profile.image.substring(0, 255);
        profile.text = profile.text.substring(0, 255);

        // Stringify the literal to guarantee I only get the keys I want
        var profilejson = JSON.stringify({
            image: profile.image,
            text: profile.text
        });

        db.query("UPDATE `users` SET profile=? WHERE name=?", [profilejson, name],
        function (err, result) {
            callback(err, err ? null : true);
        });
    },

    generatePasswordReset: function (ip, name, email, callback) {
        if (typeof callback !== "function") {
            return;
        }

        callback("generatePasswordReset is not implemented", null);
    },

    recoverPassword: function (hash, callback) {
        if (typeof callback !== "function") {
            return;
        }

        callback("recoverPassword is not implemented", null);
    },

    /**
     * Retrieve a list of channels owned by a user
     */
    getChannels: function (name, callback) {
        if (typeof callback !== "function") {
            return;
        }

        db.query("SELECT * FROM `channels` WHERE owner=?", [name], callback);
    },

    /**
     * Retrieves all names registered from a given IP
     */
    getAccounts: function (ip, callback) {
        if (typeof callback !== "function") {
            return;
        }

        db.query("SELECT name,global_rank FROM `users` WHERE `ip`=?", [ip],
                 callback);
    }
};