/**
 * Copyright 2014 IBM Corp.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 **/

var RED = require(process.env.NODE_RED_HOME+"/red/red");
var util = require("util");
var exec = require('child_process').exec;
var fs =  require('fs');

if (!fs.existsSync("/usr/local/bin/gpio")) {
    exec("cat /proc/cpuinfo | grep BCM27",function(err,stdout,stderr) {
        if (stdout.indexOf('BCM27') > -1) {
            util.log('[36-rpi-gpio.js] Error: Cannot find Wiring-Pi "gpio" command. http://wiringpi.com/download-and-install/');
        }
        // else not on a Pi so don't worry anyone with needless messages.
    });
    return;
}

// Map physical P1 pins to Gordon's Wiring-Pi Pins (as they should be V1/V2 tolerant)
var pintable = {
// Physical : WiringPi
        "Amber LED":"0",
        "Buzzer ":"1",
        "Red LED":"2",
        "Out E":"3",
        "Out F":"4",
        "Out G":"5",
        "Out H":"6",
        "Green LED":"7",
        "In C":"10",
        "In B":"11",
        "In D":"12",
        "In A":"13",
        "Red Button":"14",
}
var tablepin = {
// WiringPi : Physical
        "0":"Amber",
        "1":"Buzzer",
        "2":"Red",
        "3":"E",
        "4":"F",
        "5":"G",
        "6":"H",
        "7":"Green",
       "10":"C",
       "11":"B",
       "12":"D",
       "13":"A",
       "14":"R",
}

function PibrellaIn(n) {
    RED.nodes.createNode(this,n);
    this.buttonState = -1;
    this.pin = pintable[n.pin];
    var node = this;

    if (this.pin) {
        exec("gpio mode "+node.pin+" in", function(err,stdout,stderr) {
            if (err) node.error(err);
            else {
                node._interval = setInterval( function() {
                    exec("gpio read "+node.pin, function(err,stdout,stderr) {
                        if (err) node.error(err);
                        else {
                            if (node.buttonState !== Number(stdout)) {
                                var previousState = node.buttonState;
                                node.buttonState = Number(stdout);
                                if (previousState !== -1) {
                                    var msg = {topic:"pibrella/"+tablepin[node.pin], payload:node.buttonState};
                                    node.send(msg);
                                }
                            }
                        }
                    });
                }, 200);
            }
        });
    }
    else {
        this.error("Invalid GPIO pin: "+this.pin);
    }
}

function PibrellaOut(n) {
    RED.nodes.createNode(this,n);
    this.pin = pintable[n.pin];
    var node = this;

    if (this.pin == "1") {
        exec("gpio mode 1 pwm");
        process.nextTick(function() {
            exec("gpio pwm-ms");
            node.on("input", function(msg) {
                var out = Number(msg.payload);
                if (out == 1) { out = 2; } // doesn't work with 1...
                if (out == 0) { exec("gpio pwm 1 0"); }
                else {
                    exec("gpio pwm 1 511");
                    exec("gpio pwmc "+out);
                }
            });
        });
    }
    else if (this.pin) {
        process.nextTick(function() {
            exec("gpio mode "+node.pin+" out", function(err,stdout,stderr) {
                if (err) node.error(err);
                else {
                    node.on("input", function(msg) {
                        if (msg.payload === "true") msg.payload = true;
                        if (msg.payload === "false") msg.payload = false;
                        var out = Number(msg.payload);
                        if ((out == 0)|(out == 1)) {
                            exec("gpio write "+node.pin+" "+out, function(err,stdout,stderr) {
                                if (err) node.error(err);
                            });
                        }
                        else node.warn("Invalid input - not 0 or 1");
                    });
                }
            });
        });
    }
    else {
        this.error("Invalid GPIO pin: "+this.pin);
    }
}

exec("gpio mode 0 out",function(err,stdout,stderr) {
    if (err) {
        util.log('[36-rpi-gpio.js] Error: "gpio" command failed for some reason.');
    }
    exec("gpio mode 1 out");
    exec("gpio mode 2 out");
    exec("gpio mode 3 out");
    exec("gpio mode 4 out");
    exec("gpio mode 5 out");
    exec("gpio mode 6 out");
    exec("gpio mode 7 out");
    exec("gpio mode 10 in");
    exec("gpio mode 11 in");
    exec("gpio mode 12 in");
    exec("gpio mode 13 in");
    exec("gpio mode 14 in",function(err,stdout,stderr) {
        RED.nodes.registerType("rpi-pibrella in",PibrellaIn);
        RED.nodes.registerType("rpi-pibrella out",PibrellaOut);

        PibrellaIn.prototype.close = function() {
            clearInterval(this._interval);
        }

        PibrellaOut.prototype.close = function() {
            exec("gpio mode "+this.pin+" in");
        }

    });
});