#! /usr/bin/env python
# ======================================================================
#
# Filename: scriptutil.py
#
# Created: 01-DEC-1999,   Harry L. Melanson
#
# ======================================================================

"""A set of utilities for writing python scripts.

This module contains utilities used to write python scripts.

"""

# ======================================================================

import sys
import os
import string
import re

# ======================================================================

__author__ = 'Harry L. Melanson, melanson@fnal.gov'
__version__ = '00.00.01'
__filename__ = 'scriptutil.py'
__doc__ = __doc__ % vars()


# ======================================================================

def errorMsg(msg, doc=""):
    
    sys.stderr.write('\nERROR: %s: %s\n' % (os.path.basename(sys.argv[0]), msg))
    print "\n" + msg
    sys.stderr.write(doc)
    print "\n" + 50*"-"
    
# ======================================================================

def FatalError(msg, doc=""):
    
    sys.stderr.write('\nERROR: %s: %s\n' % (os.path.basename(sys.argv[0]), msg))
    sys.stderr.write(doc)
    print "\n" + 50*"-"
    sys.exit(-1)
    
# ======================================================================

class Option:
    """A command line option.

    **Public Data Members:**

    * flag:  The option flag (eg. -h)
    * value:  The option value (if any)

    **Constructor:**

    Option(flag, value)
    
    """

    def __init__(self, flag, value):
        self.flag = flag
        self.value = value


# ======================================================================

class ConfigOptions:
    """A collection of configuration options and switches."""
    
    def __init__(self):

        self.options = {}
        self.switches = {}

    def __repr__(self):

        s = []
        s.append('\nOptions\n')
        for key in self.options.keys():
            s.append('%s = %s\n' % (key, self.options[key]))
            
        s.append('\nSwitches\n')
        for key in self.switches.keys():
            s.append('%s = %s\n' % (key, self.switches[key]))

        return string.join(s, '')

    def opt(self, key):
        if self.options.has_key(key):
            return self.options[key]
        else:
            print
            print "ERROR: Option", key, "does not exist."
            print
            return None
            
    def switch(self, key):
        if self.switches.has_key(key):
            return self.switches[key]
        else:
            print
            print "ERROR: Switch", key, "does not exist."
            print
            return None
            
# ======================================================================
        
# ======================================================================
        
def getOptions(options, long_options, doc):
    """Get options from the command line.

    Supports -h, -?, --help options automatically.  If user specifies
    -h, -? or --help on the command line, then the calling module's documentation
    is displayed, and the command exits.
    
    **Arguments:**

    * options:  allowed options (see getopt module)
    * long_options:  allowed long options (see getopt module)
    * doc:  documenation used when -h option selected (eg. calling module's __doc__ string)

    **Return Values:**

    * optlist:  list of Option's
    * args:  list of command arguments

    """

    import getopt
    import os

    # ----------------------------------------
    #  Support -h, -?, --help
    
    allowed_options = options + 'h?'
    allowed_long_options = long_options
    allowed_long_options.append('help')

    # -----------------------------------------------------
    #  Get options from command line, and process any error
    
    try:
        opts, args = getopt.getopt(sys.argv[1:], allowed_options, allowed_long_options)
    except getopt.error, msg:
        sys.stderr.write('\nERROR: %s: %s\n' % (os.path.basename(sys.argv[0]), msg))
	sys.stderr.write(doc)
	sys.exit(-1)

    # ----------------------------------------
    #  Support help option

    for opt in opts:
        if opt[0] in ('-h', '-?', '--help'):
            print "\nNAME: ", (os.path.basename(sys.argv[0]))
            print "\n", doc
            sys.exit(0)

    # ----------------------------------------
    #  Make a list of Option's
    
    optlist = []
    for opt in opts:
        optlist.append(Option(opt[0],opt[1]))

    # --------------------------------------------------
    #  Return the list of Option's and the command arg's
    
    return optlist, args


# ======================================================================

class FileInfo:
    """Holds information about a file.

    **Public Data Members:**
        
    * name:  file's name (eg. 'readme.txt')
    * prefix:  file's prefix (eg. 'readme')
    * extension:  file's extension (eg. 'txt')
    * protection:  file's protection flags
    * owner:  file's owner
    * group:  file's group
    * size:  file's size
    * lastmod:  file's date of last modification

    **Constructor:**

    FileInfo(lsline)

    * lsline:  a line resulting from an ls -la command

    """
    
    # ----------------------------------------
    
    def __init__(self, lsline):
        
	items = string.split(lsline)
	if len(items) >= 9:
	    filename = string.split(items[8],"/")
	    self.name = filename[len(filename)-1]              # Name of file
            self.prefix = string.join(string.split(self.name,'.')[:-1])
            self.extension = string.split(self.name,'.')[-1]   # File extension
	    self.protection = items[0]        # File protection
	    self.owner = items[2]             # File owner
	    self.group = items[3]             # File group
	    self.size = items[4]              # File size
	    self.lastmod = (items[5] + " " +  # Last modified date
			    items[6] + " " +
			    items[7] )
	else:
	    raise RuntimeError

    # ----------------------------------------
    
    def __repr__(self):
        
	repr =  (self.name + " " +
		 self.owner + " " +
		 self.group + " " +
		 self.size + " " +
		 self.lastmod + " " +
		 self.protection)

	return repr

# ----------------------------------------
    
def sameFileInfos(a, b, checkowner=1):
    """Compare two FileInfo's.
    
    Return true if they are the same.
    """
    
    if (a.name == b.name and
        a.size == b.size and
        a.lastmod == b.lastmod and
        a.protection == b.protection):
        
        if checkowner:
            if (a.owner == b.owner and
                a.group == b.group):
                return 1
            else:
                return 0
        else:
            return 1
        
    else:
        return 0
	
    
# ======================================================================

def getFileList(dir,filespec):
    """ Get the list of files in a specified directory.

    **Arguments:**

    * dir:  the directory
    * filespec:  specifies which files to consider (wildcards supported)

    **Return value:**

    * A list of FileInfo's

    **Limitations:**

    Only works on systems which support the Unix command *ls -la*.
    
    """

    # ----------------------------------------
    #  Build a list of files
    
    list = []
    
    #  Issue an ls command, and get the list of files

    if dir[-1] != "/":
	dir = dir + "/"

    if filespec == '*':
        filespec = ''
        
    command = "ls -la " + dir + filespec

    for line in os.popen(command,'r').readlines():
        if len(line) >= 6:
            if line[0:5] != "total":
                file = FileInfo(line)
                if file.name != '.' and file.name != '..':
                    list.append(file)

    return list

# ======================================================================

def getDirectories(dir):
    """Get subdirectories in a given directory.

    **Arguments:**

    * dir:  the directory

    **Return:**

    * A list of FileInfo's which are really directories
    
    """

    result = []
    filelist = getFileList(dir,'')

    for file in filelist:
        if file.protection[0] == 'd':
            result.append(file)

    return result

# ======================================================================

def getFiles(dir, filespec):
    """Get files in a given directory.

    **Arguments:**

    * dir:  the directory
    * filespec:  specifies which files to consider (wildcards supported)

    **Return:**

    * A list of FileInfo's which are really files (not directories)
    
    """

    result = []
    filelist = getFileList(dir,filespec)

    for file in filelist:
        if file.protection[0] != 'd':
            result.append(file)

    return result

# ======================================================================
#  Self-test

if __name__ == '__main__':
    sys.exit()