#!/usr/bin/env python

import os
import sys
import getopt
import popen2

class dmenu_wrapper:
    def __init__ (self):
        self.prompt = "run:"
        self.history_file = None
        self.first = ""
        self.run = None
        self.number = 20

        self.font = "-nil-profont-medium-r-normal--15-150-72-72-c-70-iso8859-1"
        self.normal_bg = "#505050"
        self.normal_fg = "#eeeeee"
        self.selected_bg = "#373737"
        self.selected_fg = "#ffffff"


    def usage (self):
        """Displays a message showing how to use the program."""

        print "Usage:\n"
        print "  -r, --run        The command to run the selected entry with"
        print "  -p, --prompt     The text prompt"
        print "  -c, --commands   The text file to read previous commands from"
        print "  -f, --first      The entry to select first"
        print "  -n, --number     The number of entries to limit the command file to"


    def display (self):
        commands = []

        try:
            history_file = open (self.history_file, "r")

            # add each line to the entries list

            for line in history_file:
                line = line.rstrip ("\n")
                if not line in commands and line != self.first:
                    commands.append (line)

            history_file.close ()

            if self.first:
                commands.append (self.first)

        except IOError:
            if self.first:
                commands.append (self.first)


        # reverse the list so the commands are in the right order
        commands.reverse ()
        
        # form the dmenu command
        dmenu_command = "echo -e '%s' | dmenu -fn '%s' -nb '%s' -nf '%s' -sb '%s' -sf '%s' -p '%s'" \
                        % ("\n".join (commands), self.font, self.normal_bg, self.normal_fg,
                           self.selected_bg, self.selected_fg, self.prompt)

        # reverse them again so they're in the right order for saving
        commands.reverse ()

        # open the dmenu process
        pipe = popen2.Popen4 (dmenu_command)

        try:
            # get the selection
            command = pipe.fromchild.readlines ()[0]
        except IndexError:
            # no selection picked
            command = ""

        # get the return code
        return_code = pipe.wait ()

        # quit if they pressed escape or ^G
        if return_code != 0:
            sys.exit ()
            
        # remove the selection from the list
        try:
            commands.remove (command)
        except ValueError:
            pass
        
        # don't append the selection if it's already the last one or if it's empty
        if command and command != " " and command not in commands:
            commands.append (command)

        # save the new entries
        if commands:
            # keep the number of entries to a minimum
            commands = commands[-self.number:]

            try:
                history_file = open (self.history_file, "w")
                history_file.write ("\n".join (commands))
                history_file.close ()
            except IOError:
                print "Failed to open command file, commands will not be saved\n"
                

        # put the executable in front of the selection
        if self.run:
            command = self.run + " " + command

        # run the command

        args = command.split(" ")
        executable = args[0]
        os.execvp (executable, args)


    def main (self, argv):
        try:
            # Top, right, bottom and left take arguments. Help doesn't
            opts, args = getopt.getopt (argv, "hp:c:f:r:n:", ["help", "prompt=", "commands=",
                                                            "first=", "run=", "number="])

        except getopt.GetoptError:
            # Display the usage message then exit
            self.usage ()
            sys.exit ()

        # Make sense of the arguments
        for opt, arg in opts:
            if opt in ("-h", "--help"):
                self.usage ()
                sys.exit ()

            elif opt in ("-p", "--prompt"):
                self.prompt = arg

            elif opt in ("-c", "--commands"):
                self.history_file = arg

            elif opt in ("-f", "--first"):
                self.first = arg

            elif opt in ("-r", "--run"):
                self.run = arg
                
            elif opt in ("-n", "--number"):
                self.number = int (arg) + 1

        if self.history_file:
            self.display ()
        else:
            print "No command file given"
            self.usage ()


if __name__ == "__main__":
    dmenu_wrapper ().main (sys.argv[1:])