#!/usr/bin/env python3

"""
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 (ignored when loading
   existing stats).
-h, --help
   Show an help message.

LICENSE
-------

Copyright (c) 2011, Elena Grandi, Diego Roversi
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright
 notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
 notice, this list of conditions and the following disclaimer in the
 documentation and/or other materials provided with the distribution.
* Neither the name of the <organization> nor the
 names of its contributors may be used to endorse or promote products
 derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

"""

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():
            for i in range(min(self.context, len(name))):
                self._increment_stats(name[0:i], name[i])
            for i in range(self.context, len(name)):
                self._increment_stats(name[i-self.context:i], name[i])

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

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

    def generate_name(self):
        """Generate a name."""
        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 is None and opt.list is 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 {stats} for reading.\n".format(stats=opt.stats))
    except TypeError:
        pass
    else:
        try:
            mystats.load_stats(fp)
            need_list = False
        except ValueError:
            sys.stderr.write("{stats} is not a valid stats file.\n".format(
                stats=opt.stats
                ))
        finally:
            fp.close()

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

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

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

    for i in range(n):
        print(mystats.generate_name(), end=' ')


if __name__ == '__main__':
    main()