#!/usr/bin/env python

# Copyright (C) 2007, Eduardo Silva (edsiper@gmail.com).
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

import os
import gtk, gobject
import gtk.gdk
import cairo
import string
import drwarea


class CPU_Usage:
    
    CPU_HZ = 0
    last_jiffies = 0
    times = 0
    
    def __init__(self):
        self.CPU_hz = os.sysconf(2)
        
    def _get_CPU_data(self):
        # Uptime info
        stat_file = "/proc/stat"
        
        try:
            infile = file(stat_file, "r")
        except:
            print "Error trying uptime file"
            return -1
            
        stat_line = infile.readline()
        cpu_info = string.split(stat_line, ' ')
        infile.close()
                    
        return cpu_info
    
    def _get_CPU_usage(self):
        
        cpu_info = self._get_CPU_data()
        
        used_jiffies = (int(cpu_info[2]) + int(cpu_info[3]) + int(cpu_info[4]))
        
        if self.times ==0:
            self.last_jiffies = used_jiffies
            self.times +=1
            return True
        
        new_ujiffies = (used_jiffies - self.last_jiffies)
        new_ajiffies = ((self.frequency/1000) * self.CPU_hz)

        if new_ajiffies <= 0:
            pcpu = 0.0
        else:
            pcpu = ((new_ujiffies*100)/new_ajiffies)

        if pcpu >100:
            pcpu = 100
            
        self.times +=1
        self.last_jiffies = used_jiffies
        
        return pcpu

class Interface:
    
    context = None
    frequency_timer = 1
    graph_offset = 7
    
    def __init__(self):    

        self.drw_width = gtk.gdk.screen_width() * 90 / 100
        self.drw_height = gtk.gdk.screen_height() * 20 / 100
        self.y_cpu = self.drw_height - self.graph_offset
        self.drw_buffer = []
                        
        drawingarea = gtk.DrawingArea()
        drawingarea.set_size_request(self.drw_width, self.drw_height)
        drawingarea.connect("expose-event", self.do_expose)

        self.dat = drwarea.Drawing_Area_Tools(drawingarea)
        
        fixed = gtk.Fixed();
        fixed.set_border_width(10)
        fixed.add(drawingarea)
        
        self.frame = gtk.Frame('System CPU Usage: 0%')
        self.frame.set_border_width(10)
        self.frame.add(fixed)
        
        self.widget = self.hbox = gtk.HBox(False, 3)
        self.hbox.pack_start(self.frame, True, True, 0)
        self.hbox.show_all()
        
        DRW_CPU = CPU_Usage()
        DRW_CPU.frequency = 1000 # 1 Second
        
        gobject.timeout_add(DRW_CPU.frequency, self._draw_cpu_usage, DRW_CPU, drawingarea)
        
    def _draw_cpu_usage(self, DRW_CPU, drwarea):
        # End of the graph ?
        if ((self.frequency_timer + 1)*self.graph_offset) >= (self.drw_width - self.graph_offset):
            self.frequency_timer = 1
            self.drw_buffer = []
            self.do_expose(drwarea, None)
            
        context = drwarea.window.cairo_create()
        
        from_x = self.frequency_timer * self.graph_offset
        from_y = self.y_cpu

        self.frequency_timer += 1
        
        pcpu = DRW_CPU._get_CPU_usage()
        
        self.drw_buffer.append(pcpu)
                
        to_x = self.frequency_timer * self.graph_offset
        self.y_cpu = to_y = self._get_y_cpu(pcpu)
            
        # Context properties
        context.set_line_width(2)
        context.set_source_rgb(0,1,0)
            
        cpu_label = str(round(pcpu, 4))
        self.frame.set_label('System CPU Usage: ' + cpu_label + ' %')
    
        self.dat.draw_line(context, from_x, from_y, to_x, to_y)
        context.stroke()
            
        return True
    
    def _get_y_cpu(self, pcpu):

        height = (self.dat.range_y['to']) - (self.dat.range_y['from'])
        
        # Get percent of cpu usage
        y_value	= (height - ((pcpu*height)/100) + 4)

        return int(y_value) 
    
    def do_expose(self, widget, event):
        
        self.context = widget.window.cairo_create()
        self.context.rectangle(0, 0, self.dat.width - 1, self.dat.height - 1)

        self.context.set_source_rgb (0,0,0)
        self.context.fill_preserve()

        # Drawing horizontal and vertical border lines
        self.dat.draw_border_lines(self.context)
        
        # Drawing grid
        line_margin = self.dat.margin
        self.context.set_source_rgb(1, 1, 1)
        self.context.set_line_width(1)
        self.dat.draw_grid(self.context, line_margin + 1, line_margin + 1, self.dat.width - line_margin - 2, self.dat.height - line_margin - 2)
        self.context.stroke()

        self._draw_buffer(widget)
        return False

    def _draw_buffer(self, drwarea):
        freq = 1 # Frequency timer
        last_y = self.drw_height - self.graph_offset
        
        context = drwarea.window.cairo_create()		
        for pcpu in self.drw_buffer:
            
            from_x = freq * self.graph_offset
            from_y = last_y
    
            freq+=1
            
            to_x = freq * self.graph_offset
            last_y = to_y = self._get_y_cpu(pcpu)
                
            # Context properties
            context.set_line_width(2)
            context.set_source_rgb(0,1,0)
                
            self.dat.draw_line(context, from_x, from_y, to_x, to_y)
            context.stroke()