#!/usr/bin/env python
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from __future__ import print_function

import optparse
import os
import re
import sys
import rosbag.migration

import genpy.message
import genpy.dynamic

def print_trans(old, new, indent):
    from_txt = '%s [%s]' % (old._type, old._md5sum)
    if new is not None:
        to_txt= '%s [%s]' % (new._type, new._md5sum)
    else:
        to_txt = 'Unknown'
    print('    ' * indent + ' * From: %s' % from_txt)
    print('    ' * indent + '   To:   %s' % to_txt)

if __name__ == '__main__':
    parser = optparse.OptionParser(usage='usage: makerule.py msg.saved [-a] output_rulefile [rulefile1, rulefile2, ...] [-n]')
    parser.add_option('-a', '--append',    action='store_true', dest='append',    default=False)
    parser.add_option('-n', '--noplugins', action='store_true', dest='noplugins', default=False)
    (options, args) = parser.parse_args()

    if len(args) < 2:
        parser.error("Incorrect number of arguments")

    rulefile = args[1]

    if os.path.isfile(rulefile) and not options.append:
        print("The file %s already exists.  Include -a if you intend to append." % rulefile, file=sys.stderr)
        exit(1)

    if not os.path.isfile(rulefile) and options.append:
        print("The file %s does not exist, and so -a is invalid." % rulefile, file=sys.stderr)
        exit(1)

    if options.append:
        append_rule = [rulefile]
    else:
        append_rule = []

    f = open(args[0])
    if f is None:
        print('Could not open message full definition: %s', file=sys.stderr)
        sys.exit()

    type_line = f.readline()
    pat = re.compile(r"\[(.*)]:")
    type_match = pat.match(type_line)
    if type_match is None:
        print("Full definition file malformed.  First line should be: '[my_package/my_msg]:'", file=sys.stderr)
        sys.exit()

    old_type = type_match.groups()[0]
    old_full_text = f.read()
    f.close()

    old_class = genpy.dynamic.generate_dynamic(old_type,old_full_text)[old_type]

    if old_class is None:
        print('Could not generate class from full definition file.', file=sys.stderr)
        sys.exit()

    mm = rosbag.migration.MessageMigrator(args[2:]+append_rule,not options.noplugins)

    migrations = rosbag.migration.checkmessages(mm, [old_class])

    if migrations == []:
        print('Saved definition is up to date.')
        exit(0)

    print('The following migrations need to occur:')

    all_rules = []
    for m in migrations:
        all_rules.extend(m[1])

        print_trans(m[0][0].old_class, m[0][-1].new_class, 0)
        if len(m[1]) > 0:
            print("    %d rules missing:" % len(m[1]))
            for r in m[1]:
                print_trans(r.old_class, r.new_class, 1)

    if rulefile is None:
        print("rulefile not specified")
    else:
        output = ''
        rules_left = mm.filter_rules_unique(all_rules)

        if rules_left == []:
            print("\nNo additional rule files needed to be generated.  %s not created." % rulefile)
            exit(0)

        while rules_left != []:
            extra_rules = []

            for r in rules_left:
                if r.new_class is None:
                    print("The message type %s appears to have moved.  Please enter the type to migrate it to." % r.old_class._type)
                    new_type = raw_input('>')
                    new_class = genpy.message.get_message_class(new_type)
                    while new_class is None:
                        print("\'%s\' could not be found in your system.  Please make sure it is built." % new_type)
                        new_type = raw_input('>')
                        new_class = genpy.message.get_message_class(new_type)
                    new_rule = mm.make_update_rule(r.old_class, new_class)
                    R = new_rule(mm, 'GENERATED.' + new_rule.__name__)
                    R.find_sub_paths()
                    new_rules = [r for r in mm.expand_rules(R.sub_rules) if r.valid == False]
                    extra_rules.extend(new_rules)
                    print('Creating the migration rule for %s requires additional missing rules:' % new_type)
                    for nr in new_rules:
                        print_trans(nr.old_class, nr.new_class,1)
                    output += R.get_class_def()
                else:
                    output += r.get_class_def()
            rules_left = mm.filter_rules_unique(extra_rules)
        f = open(rulefile, 'a')
        f.write(output)
        f.close()
        print("\nThe necessary rule files have been written to: %s" % rulefile)