var path = require("path");
var fs = require("fs");
var webserver = require("./webserver");
var sendJade = require("./jade").sendJade;
var Logger = require("../logger");
var db = require("../database");
var Config = require("../config");

function checkAdmin(cb) {
    return function (req, res) {
        webserver.logRequest(req);
        var auth = req.cookies.auth;
        if (!auth) {
            res.send(403);
            return;
        }
        db.users.verifyAuth(auth, function (err, user) {
            if (err) {
                if (err === "Invalid auth string" ||
                    err === "Auth string does not match an existing user") {
                    res.send(403);
                } else {
                    res.send(500);
                }
                return;
            }

            if (user.global_rank < 255) {
                res.send(403);
                Logger.eventlog.log("[acp] Attempted GET /acp from non-admin " +
                                    user.name + "@" + webserver.ipForRequest(req));
                return;
            }

            cb(req, res, user);
        });
    };
}

/**
 * Handles a request for the ACP
 */
function handleAcp(req, res, user) {
    var sio;
    if (req.secure) {
        sio = Config.get("https.domain") + ":" + Config.get("https.port");
    } else {
        sio = Config.get("http.domain") + ":" + Config.get("io.port");
    }
    sio += "/socket.io/socket.io.js";

    sendJade(res, "acp", {
        loginName: user.name,
        loggedIn: true,
        sioSource: sio
    });
}

/**
 * Streams the last length bytes of file to the given HTTP response
 */
function readLog(res, file, length) {
    fs.stat(file, function (err, data) {
        if (err) {
            res.send(500);
            return;
        }

        var start = Math.max(0, data.size - length);
        if (isNaN(start)) {
            res.send(500);
        }
        var end = Math.max(0, data.size - 1);
        if (isNaN(end)) {
            res.send(500);
        }
        fs.createReadStream(file, { start: start, end: end })
            .pipe(res);
    });
}

/**
 * Handles a request to read the syslog
 */
function handleReadSyslog(req, res) {
    readLog(res, path.join(__dirname, "..", "..", "sys.log"), 1048576);
}

/**
 * Handles a request to read the error log
 */
function handleReadErrlog(req, res) {
    readLog(res, path.join(__dirname, "..", "..", "error.log"), 1048576);
}

/**
 * Handles a request to read the http log
 */
function handleReadHttplog(req, res) {
    readLog(res, path.join(__dirname, "..", "..", "http.log"), 1048576);
}

/**
 * Handles a request to read a channel log
 */
function handleReadChanlog(req, res) {
    if (!req.params.name.match(/^[\w-]{1,30}$/)) {
        res.send(400);
        return;
    }
    readLog(res, path.join(__dirname, "..", "..", "chanlogs", req.params.name + ".log"), 1048576);
}

module.exports = {
    init: function (app) {
        app.get("/acp", checkAdmin(handleAcp));
        app.get("/acp/syslog", checkAdmin(handleReadSyslog));
        app.get("/acp/errlog", checkAdmin(handleReadErrlog));
        app.get("/acp/httplog", checkAdmin(handleReadHttplog));
        app.get("/acp/chanlog/:name", checkAdmin(handleReadChanlog));
    }
};