'use strict';
// ==================================================================================
// index.js
// ----------------------------------------------------------------------------------
// Description:   System Information - library
//                for Node.js
// Copyright:     (c) 2014 - 2016
// Author:        Sebastian Hildebrandt
// ----------------------------------------------------------------------------------
// License:       MIT
// ==================================================================================
// 8. File System
// ----------------------------------------------------------------------------------

const os = require('os');
const exec = require('child_process').exec;
const fs = require('fs');
const util = require('./util');

let _platform = os.type();

const _linux = (_platform == 'Linux');
const _darwin = (_platform == 'Darwin');
const _windows = (_platform == 'Windows_NT');
const NOT_SUPPORTED = 'not supported';

let _fs_speed = {};
let _disk_io = {};

// --------------------------
// FS - devices

function fsSize(callback) {

  return new Promise((resolve, reject) => {
    process.nextTick(() => {
      if (_windows) {
        let error = new Error(NOT_SUPPORTED);
        if (callback) { callback(NOT_SUPPORTED) }
        reject(error);
      }

      exec("df -lk | grep ^/", function (error, stdout) {
        let data = [];
        if (!error) {
          let lines = stdout.toString().split('\n');
          //lines.splice(0, 1);
          lines.forEach(function (line) {
            if (line != '') {
              line = line.replace(/ +/g, " ").split(' ');
              data.push({
                'fs': line[0],
                'size': parseInt(line[1]) * 1024,
                'used': parseInt(line[2]) * 1024,
                'use': parseFloat((100.0 * line[2] / line[1]).toFixed(2)),
                'mount': line[line.length - 1]
              })
            }
          });
        }
        if (callback) { callback(data) }
        resolve(data);
      });
    });
  });
}

exports.fsSize = fsSize;

// --------------------------
// FS - speed

function fsStats(callback) {

  return new Promise((resolve, reject) => {
    process.nextTick(() => {
      if (_windows) {
        let error = new Error(NOT_SUPPORTED);
        if (callback) { callback(NOT_SUPPORTED) }
        reject(error);
      }

      var result = {
        rx: 0,
        wx: 0,
        tx: 0,
        rx_sec: -1,
        wx_sec: -1,
        tx_sec: -1,
        ms: 0
      };

      if (_linux) {
//		exec("df -k | grep /dev/", function(error, stdout) {
        exec("lsblk | grep /", function (error, stdout) {
          if (!error) {
            let lines = stdout.toString().split('\n');
            let fs_filter = [];
            lines.forEach(function (line) {
              if (line != '') {
                line = line.replace(/[├─│└]+/g, "").trim().split(' ');
                if (fs_filter.indexOf(line[0]) == -1) fs_filter.push(line[0])
              }
            });

            let output = fs_filter.join('|');
            exec("cat /proc/diskstats | egrep '" + output + "'", function (error, stdout) {
              if (!error) {
                let lines = stdout.toString().split('\n');
                lines.forEach(function (line) {
                  line = line.trim();
                  if (line != '') {
                    line = line.replace(/ +/g, " ").split(' ');

                    result.rx += parseInt(line[5]) * 512;
                    result.wx += parseInt(line[9]) * 512;
                  }
                });
                result.tx = result.rx + result.wx;
                if (_fs_speed && _fs_speed.ms) {
                  result.ms = Date.now() - _fs_speed.ms;
                  result.rx_sec = (result.rx - _fs_speed.bytes_read) / (result.ms / 1000);
                  result.wx_sec = (result.wx - _fs_speed.bytes_write) / (result.ms / 1000);
                  result.tx_sec = result.rx_sec + result.wx_sec;
                } else {
                  result.rx_sec = -1;
                  result.wx_sec = -1;
                  result.tx_sec = -1;
                }
                _fs_speed.bytes_read = result.rx;
                _fs_speed.bytes_write = result.wx;
                _fs_speed.bytes_overall = result.rx + result.wx;
                _fs_speed.ms = Date.now();
              }
              if (callback) { callback(result) }
              resolve(result);
            })
          } else {
            if (callback) { callback(result) }
            resolve(result);
          }
        })
      }
      if (_darwin) {
        exec("ioreg -c IOBlockStorageDriver -k Statistics -r -w0 | sed -n '/IOBlockStorageDriver/,/Statistics/p' | grep 'Statistics' | tr -cd '01234567890,\n' | awk -F',' '{print $3, $10}'", function (error, stdout) {
          if (!error) {
            let lines = stdout.toString().split('\n');
            lines.forEach(function (line) {
              line = line.trim();
              if (line != '') {
                line = line.split(' ');

                result.rx += parseInt(line[0]);
                result.wx += parseInt(line[1]);
              }
            });
            result.tx = result.rx + result.wx;
            if (_fs_speed && _fs_speed.ms) {
              result.ms = Date.now() - _fs_speed.ms;
              result.rx_sec = (result.rx - _fs_speed.bytes_read) / (result.ms / 1000);
              result.wx_sec = (result.wx - _fs_speed.bytes_write) / (result.ms / 1000);
              result.tx_sec = result.rx_sec + result.wx_sec;
            } else {
              result.rx_sec = -1;
              result.wx_sec = -1;
              result.tx_sec = -1;
            }
            _fs_speed.bytes_read = result.rx;
            _fs_speed.bytes_write = result.wx;
            _fs_speed.bytes_overall = result.rx + result.wx;
            _fs_speed.ms = Date.now();
          }
          if (callback) { callback(result) }
          resolve(result);
        })
      }
    });
  });
}

exports.fsStats = fsStats;

function disksIO(callback) {

  return new Promise((resolve, reject) => {
    process.nextTick(() => {
      if (_windows) {
        let error = new Error(NOT_SUPPORTED);
        if (callback) { callback(NOT_SUPPORTED) }
        reject(error);
      }

      var result = {
        rIO: 0,
        wIO: 0,
        tIO: 0,
        rIO_sec: -1,
        wIO_sec: -1,
        tIO_sec: -1,
        ms: 0
      };
      if (_linux) {
        // prints Block layer statistics for all mounted volumes
        // var cmd = "for mount in `lsblk | grep / | sed -r 's/│ └─//' | cut -d ' ' -f 1`; do cat /sys/block/$mount/stat | sed -r 's/ +/;/g' | sed -r 's/^;//'; done";
        // var cmd = "for mount in `lsblk | grep / | sed 's/[│└─├]//g' | awk '{$1=$1};1' | cut -d ' ' -f 1 | sort -u`; do cat /sys/block/$mount/stat | sed -r 's/ +/;/g' | sed -r 's/^;//'; done";
        let cmd = "for mount in `lsblk | grep ' disk ' | sed 's/[│└─├]//g' | awk '{$1=$1};1' | cut -d ' ' -f 1 | sort -u`; do cat /sys/block/$mount/stat | sed -r 's/ +/;/g' | sed -r 's/^;//'; done";

        exec(cmd, function (error, stdout) {
          if (!error) {
            let lines = stdout.split('\n');
            lines.forEach(function (line) {
              // ignore empty lines
              if (!line) return;

              // sum r/wIO of all disks to compute all disks IO
              let stats = line.split(';');
              result.rIO += parseInt(stats[0]);
              result.wIO += parseInt(stats[4]);
            });
            result.tIO = result.rIO + result.wIO;
            if (_disk_io && _disk_io.ms) {
              result.ms = Date.now() - _disk_io.ms;
              result.rIO_sec = (result.rIO - _disk_io.rIO) / (result.ms / 1000);
              result.wIO_sec = (result.wIO - _disk_io.wIO) / (result.ms / 1000);
              result.tIO_sec = result.rIO_sec + result.wIO_sec;
            } else {
              result.rIO_sec = -1;
              result.wIO_sec = -1;
              result.tIO_sec = -1;
            }
            _disk_io.rIO = result.rIO;
            _disk_io.wIO = result.wIO;
            _disk_io.tIO = result.tIO;
            _disk_io.ms = Date.now();

            if (callback) { callback(result) }
            resolve(result);
          } else {
            if (callback) { callback(result) }
            resolve(result);
          }
        });
      }
      if (_darwin) {
        exec("ioreg -c IOBlockStorageDriver -k Statistics -r -w0 | sed -n '/IOBlockStorageDriver/,/Statistics/p' | grep 'Statistics' | tr -cd '01234567890,\n' | awk -F',' '{print $1, $11}'", function (error, stdout) {
          if (!error) {
            let lines = stdout.toString().split('\n');
            lines.forEach(function (line) {
              line = line.trim();
              if (line != '') {
                line = line.split(' ');

                result.rIO += parseInt(line[1]);
                result.wIO += parseInt(line[0]);
              }
            });

            result.tIO = result.rIO + result.wIO;
            if (_disk_io && _disk_io.ms) {
              result.ms = Date.now() - _disk_io.ms;
              result.rIO_sec = (result.rIO - _disk_io.rIO) / (result.ms / 1000);
              result.wIO_sec = (result.wIO - _disk_io.wIO) / (result.ms / 1000);
              result.tIO_sec = result.rIO_sec + result.wIO_sec;
            } else {
              result.rIO_sec = -1;
              result.wIO_sec = -1;
              result.tIO_sec = -1;
            }
            _disk_io.rIO = result.rIO;
            _disk_io.wIO = result.wIO;
            _disk_io.tIO = result.tIO;
            _disk_io.ms = Date.now();
          }
          if (callback) { callback(result) }
          resolve(result);
        })
      }
    });
  });
}

exports.disksIO = disksIO;