import subprocess
import re


classes = ['SignupInfo']

#
# Get the relevant files and Django app names for the classes we need to augment
#
class_to_file_map = {}
app_to_classes_map = {}
for clazz in classes:
    grep_str = subprocess.check_output('grep -r "class ' + clazz + '" **/models.py', shell=True)
    matches = re.search('((.*)/models\.py).*', grep_str)

    app_path = matches.group(2)
    django_app = app_path.replace('/', '.')

    class_to_file_map[clazz] = matches.group(1)

    if django_app not in app_to_classes_map:
        app_to_classes_map[django_app] = []
    app_to_classes_map[django_app].append(clazz)

#
# Edit the class definitions to no longer have "db_index=False"
#
for clazz, file in class_to_file_map.items():
    f = open(file, 'r')

    # Read the lines, then edit the correct one
    lines = f.readlines()
    for i in range(len(lines)):
        if lines[i].find('class {}'.format(clazz)) != -1:
            while True:
                i += 1
                if lines[i].find('organization =') != -1:
                    # Funky regex here to capture that db_index may be the first or last arg, which changes
                    # the position of the comma that we need to delete.
                    db_index_str = re.search('(db_index=False[,]?[\s]?|[,]?[\s]?db_index=False)', lines[i]).group(1)
                    lines[i] = lines[i].replace(db_index_str, '')
                    break
            break
    f.close()

    # Write the editted lines back to the file
    f = open(file, 'w+')
    f.writelines(lines)
    f.close()

#
# Have Django make the migrations for adding the indexes,
# then have Django spit out the SQL for those migrations,
# then yank the relevant index-creation SQL out of that and augment it to make the index concurrently.
#
app_to_index_creation_sql = {}
django_migration_files_created = []

django_migs_output = subprocess.check_output('python manage.py makemigrations', shell=True)
for line in django_migs_output.split('\n'):
    mig_number_match = re.search('([0-9]{4})_', line)
    if not mig_number_match:
        continue
    mig_number = mig_number_match.group(1)
    mig_app_name = re.search('\s([\S]+)/migrations', line).group(1)

    django_migration_file_created = re.search('\s([\S]+\.py)', line).group(1)
    django_migration_files_created.append(django_migration_file_created)

    mig_sql = subprocess.check_output('python manage.py sqlmigrate {} {}'.format(mig_app_name, mig_number), shell=True)
    index_creation_sql_lines = re.findall('(CREATE INDEX [^;]+;)', mig_sql)

    for i in range(len(index_creation_sql_lines)):
        sql_line = index_creation_sql_lines[i]
        sql_line = sql_line.replace('INDEX', 'INDEX CONCURRENTLY')
        index_creation_sql_lines[i] = sql_line

    app_to_index_creation_sql[mig_app_name] = index_creation_sql_lines

#
# These migration files are no longer created, we're gonna make new ones from scratch. NUKE TIME
#
for mig_file in django_migration_files_created:
    subprocess.check_output('rm {}'.format(mig_file), shell=True)

#
# Old migration files: Who are you?
# New migration files: I'm you but better
#
# Time to make new migration files with the SQL for making indexes concurrently
#
for django_app in app_to_classes_map.keys():
    makemig_output = subprocess.check_output('python manage.py makemigrations --empty ' + django_app, shell=True)
    new_migration_file = re.search('\s([\S]+/migrations.*\.py)', makemig_output).group(1)

    f = open(new_migration_file, 'r')

    lines = f.readlines()
    for i in range(len(lines)):
        line = lines[i]
        if line.startswith('class'):
            break

    lines.insert(i, '\n')
    for j, sql_line in enumerate(app_to_index_creation_sql[django_app]):
        lines.insert(i, 'INDEX_CREATION_SQL_{} = \'{}\'\n'.format(j, sql_line))
    lines.insert(i, 'from django.conf import settings\n')

    lines.append('    if not settings.INITIAL_DATABASE_SETUP:\n')
    for j, __ in enumerate(app_to_index_creation_sql[django_app]):
        lines.append('        operations.append(migrations.RunSQL(INDEX_CREATION_SQL_{}), migrations.RunSQL.noop)\n'.format(j))
    lines.append('    atomic = False')

    f.close()

    f = open(new_migration_file, 'w+')
    f.writelines(lines)
    f.close()

#
# Take a quick trip back in time to erase Django's memory of ever having db_index=False for the associated classes
#
for django_app, classes in app_to_classes_map.items():
    for clazz in classes:

        # We'll do this in a try/catch, since there's a chance that there have been
        # no AddField/AlterField operations on Organization for this class
        try:
            grep_output = subprocess.check_output('grep -i "\(addfield\|alterfield\|createmodel\)" {}/migrations/* -A 10 | grep -i organization -B 10 | grep -i {}'
                                                  .format(django_app.replace('.', '/'),
                                                          clazz),
                                                  shell=True)
        except:
            continue

        files_to_alter = []
        for line in grep_output.split('\n'):
            if line:
                files_to_alter.append(re.search('([\S]+\.py)', line).group(1))

        for file in files_to_alter:
            f = open(file, 'r')

            lines = f.readlines()

            upcoming_edit_line = False
            for i in range(len(lines)):
                line = lines[i]
				found_index = max(line.find(clazz.lower()), line.find(clazz))
                if found_index != -1 and line[found_index - 1] == "'":
                    upcoming_edit_line = True

                if upcoming_edit_line and line.find('db_index') != -1:
                    # Same funky regex here as before to catch the fact that the comma we need
                    # to delete may be before or after the arg but NOT BOTH
                    db_index_str = re.search('(db_index=False[,]?[\s]?|[,]?[\s]?db_index=False)', line).group(1)
                    lines[i] = line.replace(db_index_str, '')
                    upcoming_edit_line = False

            f.close()

            f = open(file, 'w+')
            f.writelines(lines)
            f.close()