#!/usr/bin/env python2

"""
namegen.py
==========

---------------------
random name generator
---------------------

:Authors: Elena ``of Valhalla'' Grandi, Diego Roversi
:Date: 2011-09-11
:Copyright: 2011 Elena Grandi, Diego Roversi
:Version: 0.20110911
:Manual Section: 1

SYNOPSIS
--------

   namegen.py (-s <stat_file>)|(-l <list_file>) [-S <dest_file>] [-n <n>]

DESCRIPTION
-----------

OPTIONS
-------

-s <stat_file>, --stats=<stat_file>
   Load rules from <stat_file>.
-l <list_file>, --list=<list_file>
   Generate rules from the files in <list_file>.
-S <dest_file>, --save_stats=<dest_file>
   Save stats in <dest_file>.
-n <n>, --number=<n>
   Generate <n> names (0 to generate no name).
-c <n>, --context=<n>
   Use <n> characters of context in the stats.
-h, --help
   Show an help message.

LICENSE
-------

"""

import json
import optparse
import sys
import random

class Stats:

    def __init__(self,context):
        """"""
        self.stats = {}
        self.context = context

    def _increment_stats(self,cont,key):
        if cont in self.stats:
            if key in self.stats[cont]:
                self.stats[cont][key] += 1
            else:
                self.stats[cont][key] = 1
        else:
            self.stats[cont] = {key: 1}

    def read_names(self,fp):
        """Calculate stats from a list of names in a file-like object."""

        for name in fp.readlines():
            name = name.decode('utf-8')
            for i in xrange(min(self.context,len(name))):
                self._increment_stats(name[0:i],name[i])
            for i in xrange(self.context,len(name)):
                self._increment_stats(name[i-self.context:i],name[i])

    def load_stats(self,fp):
        """Load stats from a yaml in a string or file-like object"""
        self.stats = json.load(fp)
        self.context = max([len(k) for k in self.stats.keys()])

    def save_stats(self,fp):
        """Save stats in yaml to a file-like object"""
        json.dump(self.stats,fp)

    def generate_name(self):
        """Generate a name following the stats"""
        name = ''
        c = ''
        while c != '\n':
            if len(name) <= self.context:
                cont = name
            else:
                cont = name[-self.context:]
            
            chars = ''.join([k*self.stats[cont][k] for k in self.stats[cont]])
            c = random.choice(chars)
            name += c

        return name

def main():
    parser = optparse.OptionParser()
    parser.add_option('--stats','-s')
    parser.add_option('--list','-l')
    parser.add_option('--save-stats','-S')
    parser.add_option('--number','-n')
    parser.add_option('--context','-c')
    opt, arg = parser.parse_args()

    if opt.stats == None and opt.list == None:
        parser.print_help()
        sys.exit(1)

    try:
        mystats = Stats(int(opt.context))
    except TypeError:
        mystats = Stats(3)

    need_list = True
    try:
        fp = open(opt.stats)
    except IOError:
        sys.stderr.write("Could not open "+opt.stats+" for reading.\n")
    except TypeError:
        pass
    else:
        try:
            mystats.load_stats(fp)
            need_list = False
        except ValueError:
            sys.stderr.write(opt.stats+" is not a valid stats file.\n")
        finally:
            fp.close()

    if need_list:
        try:
            fp = open(opt.list)
        except IOError:
            sys.stderr.write("Could not open "+opt.list+" for reading.\n")
            sys.exit(1)
        except TypeError:
            parser.print_help()
            sys.exit(1)
        else:
            try:
                mystats.read_names(fp)
            except IOError:
                sys.stderr.write(opt.list+" is not a valid name list file.\n")
                sys.exit(1)
            finally:
                fp.close()

    try:
        fp = open(opt.save_stats,'wb')
    except TypeError:
        pass
    except IOError:
        sys.stderr.write("Warning: could not save stats data on file "+
                opt.save_stats+"\n")
    else:
        try:
            mystats.save_stats(fp)
        except IOError:
            sys.stderr.write("Warning: could not save stats data on file "+
                    opt.save_stats+"\n")
        finally:
            fp.close()

    try:
        n = int(opt.number)
    except (TypeError, ValueError):
        n = 1

    for i in xrange(n):
        print mystats.generate_name(),


if __name__ == '__main__': main()