#!/usr/bin/env python
import re
import MySQLdb as mysql
from singplur import singularize
from itertools import combinations


PRIMARY_KEY = 'id'
TAB = '\t'
MODEL_NAMESPACE = ''


def php_value(data, indent=0):
    """
    Convert Python data types to PHP code. Tuples or lists are used for
    single-line arrays, sets for multiline arrays, dictionaries for associative
    arrays, and strings are encapsulated in single quotes.
    """
    if isinstance(data, str):
        return "'%s'" % data.replace("'", "\\'")

    tabs = (indent + 1) * TAB

    if type(data) in (list, tuple):
        return 'array(%s)' % ', '.join(map(php_value, data))
    elif isinstance(data, dict):
        if not data:
            return 'array()'

        lines = ["'%s' => %s" % (k, php_value(v, indent + 1))
                 for k, v in data.iteritems()]
    elif isinstance(data, set):
        if not data:
            return 'array()'

        lines = [php_value(item, indent + 1) for item in data]
    else:
        return str(data)

    return 'array(\n%s\n%s)' % (',\n'.join([tabs + line for line in lines]),
                                indent * TAB)


def php_assoc((arg, kwargs)):
    assocs = ["'%s' => %s" % (k, php_value(v)) for k, v in kwargs.iteritems()]
    return 'array(%s)' % ', '.join([php_value(arg)] + assocs)


def php_static_var(name, value):
    return 'static $%s = %s;' % (name, value)


def php_static_array(name, values):
    array = 'array(%s)' if len(values) < 2 \
            else 'array(\n{0}{0}%s\n{0})'.format(TAB)
    lines = map(php_assoc, values)
    array_values = (',\n' + 2 * TAB).join(lines)
    return php_static_var(name, array % array_values)


def php_block(php_code):
    return '<?php\n\n%s\n\n?>' % php_code


class Model(object):
    def __init__(self, table, options):
        self.table = table
        self.options = options

        self.attributes = []
        self.primary_key = []
        self.foreign_keys = []

        self.has_many = []
        self.has_one = []
        self.belongs_to = []

    def __str__(self):
        return '<Model "%s" table=%s>' % (self.name(), self.table)

    def singular_name(self):
        return singularize(self.table)

    def classname(self):
        return singularize(re.sub('(?:^|_)([a-z])',
            lambda m: m.group(1).upper(), self.table))

    def read_attributes(self, conn):
        fields = read_fields(conn, self.table)
        is_protected = lambda field: field['Key'] in ('PRI', 'MUL')
        self.protected_fields, accessible = partition(is_protected, fields)
        self.accessible_attr = [field['Field'] for field in accessible]

    def process_keys(self, models):
        for field in self.protected_fields:
            name = field['Field']

            if field['Key'] == 'PRI':
                self.primary_key.append(name)
            elif field['Key'] == 'MUL':
                self.add_foreign_key(name, models)

        # Has-many through
        if len(self.belongs_to) > 1:
            relations = [find_model(name, models)
                         for name, options in self.belongs_to]

            for a, b in combinations(relations, 2):
                a.add_has_relation(b, through=self.table)
                b.add_has_relation(a, through=self.table)

    def add_has_relation(self, model, **kwargs):
        options = self.relopts(model)
        options.update(kwargs)
        name = model.singular_name()

        if [self.singular_name(), name] in self.options.get('has_one', []):
            self.has_one.append((name, options))
        else:
            self.has_many.append((model.table, options))

    def relopts(self, model, **kwargs):
        relopts = kwargs

        if self.options.get('create_select', True):
            relopts['select'] = PRIMARY_KEY + ', ' \
                                + ', '.join(model.accessible_attr)

        return relopts

    def add_foreign_key(self, name, models):
        self.foreign_keys.append(name)
        singular = re.sub('_' + PRIMARY_KEY + '$', '', name)

        try:
            other_model = find_model(singular, models)
        except ValueError:
            return

        self.belongs_to.append((singular, self.relopts(other_model)))
        other_model.add_has_relation(self)

    def strip_array(self, attr):
        array = getattr(self, attr)

        if len(array) == 1:
            relation, opts = array[0]

            if not len(opts):
                return php_static_var(attr, php_value(relation))

    def php_has_many(self):
        stripped = self.strip_array('has_many')

        if stripped:
            return stripped

        if self.has_many:
            return php_static_array('has_many', self.has_many)

    def php_has_one(self):
        stripped = self.strip_array('has_one')

        if stripped:
            return stripped

        if self.has_one:
            return php_static_array('has_one', self.has_one)

    def php_belongs_to(self):
        stripped = self.strip_array('belongs_to')

        if stripped:
            return stripped

        if self.belongs_to:
            return php_static_array('belongs_to', self.belongs_to)

    def php_has_many_and_belongs_to(self):
        if not self.has_many or not self.belongs_to:
            return

    def php_attr_accessible(self):
        # All attributes except primary/foreign keys are accessible
        if self.accessible_attr:
            return php_static_var('attr_accessible',
                                  php_value(self.accessible_attr))

    def generate_php(self, add_php_block=False):
        # PHP delimiters
        php = '<?php\n\n%s\n\n?>'

        # Class definition
        classname = self.classname()

        if self.options.get('namespace'):
            classname = options['namespace'] + '\\' + classname

        classdef = 'class %s extends ActiveRecord\\Model {\n%%s\n}' % classname

        # Indented lines within class definition
        lines = []

        if self.options.get('create_relations', True):
            lines += [
                self.php_has_many(),
                self.php_has_one(),
                self.php_belongs_to(),
                self.php_has_many_and_belongs_to(),
            ]

        if self.options.get('create_accessible', True):
            lines.append(self.php_attr_accessible())

        php = classdef % '\n'.join([TAB + line
                                    for line in lines if line is not None])

        return php_block(php) if add_php_block else php

    def filename(self):
        return self.classname().replace('_', '') + '.php'

    def create_path_from_dir(self, dirname):
        return os.path.dirname(dirname + '//') + '/' + self.filename()

    def save_in_file(self, path):
        code = self.generate_php(True)
        f = open(path, 'w')
        f.write(code)
        f.close()


def find_model(singular_name, models):
    for model in models:
        if model.singular_name() == singular_name:
            return model

    raise ValueError('No model found for "%s".' % singular_name)


def flatten(iterable):
    return reduce(lambda a, b: a + b, map(list, iterable), [])


def create_models(conn, options):
    models = [Model(table, options) for table in read_tables(conn)]

    for model in models:
        model.read_attributes(conn)

    for model in models:
        model.process_keys(models)

    return models


def refine_model(conn, model, models):
    for field in read_fields(conn, model.table):
        model.add_attribute(field, models)


def read_tables(conn):
    cur = conn.cursor()
    cur.execute('show tables')
    tables = flatten(cur.fetchall())
    cur.close()
    return tables


def read_fields(conn, table):
    cur = conn.cursor(mysql.cursors.DictCursor)
    cur.execute('show columns from %s' % table)
    fields = cur.fetchall()
    cur.close()
    return fields


def partition(callback, iterable):
    """
    Partition an iterable into two parts using a callback that returns a
    boolean.

    Example:
    >>> partition(lambda x: x & 1, range(6))
    ([1, 3, 5], [0, 2, 4])
    """
    a, b = [], []

    for item in iterable:
        (a if callback(item) else b).append(item)

    return a, b


if __name__ == '__main__':  # pragma: nocover
    import os
    from argparse import ArgumentParser

    parser = ArgumentParser(description='Generate PHPActiveRecord models.')
    parser.add_argument('dbname', help='database name')
    parser.add_argument('-H', '--host', metavar='ADDRESS', default='localhost',
                        help='MySQL server address')
    parser.add_argument('-u', '--user', metavar='USERNAME', default='root',
                        help='MySQL username')
    parser.add_argument('-p', '--password', default='mysql12#$',
                        help='MySQL password')
    parser.add_argument('--has-one', nargs=2, dest='opt_has_one',
                        help='one-to-one relationships of the form '
                        '\'payment receipt\', where one payment has one '
                        'receipt', action='append', default=[])
    parser.add_argument('--namespace', default='', dest='opt_namespace',
                        help='PHP namespace to create models classes in')
    parser.add_argument('--create-select', action='store_true',
                        help='whether to create the \'select\' option in '
                             'relations', dest='opt_create_select')
    parser.add_argument('--create-accessible', dest='opt_create_accessible',
                        help='whether to create the \'$attr_accessible\' '
                             'variable, containing all ' 'attributes except '
                             'primary or foreing keys', action='store_true')
    parser.add_argument('-a', '--create-all', action='store_true',
                        help='create all available options and variables')
    parser.add_argument('-d', '--dir', help='directory to save model files in')
    parser.add_argument('-s', '--spaces', nargs='?', const=4, type=int,
                        help='use spaces instead of tabs (4 by default)')
    args = parser.parse_args()
    options = {}

    for arg, value in args._get_kwargs():
        if arg[:4] == 'opt_':
            options[arg[4:]] = value

    if args.create_all:
        options['create_select'] = options['create_accessible'] = True

    if args.spaces:
        TAB = args.spaces * ' '

    conn = mysql.connect(args.host, args.user, args.password, args.dbname)
    models = create_models(conn, options)
    conn.close()

    if args.dir:
        if not os.path.exists(args.dir):
            os.makedirs(args.dir)

        for model in models:
            path = model.create_path_from_dir(args.dir)
            model.save_in_file(path)
            print 'Saved model %s in %s' % (model.classname(), path)
    else:
        for model in models:
            print model.generate_php()