#!/usr/bin/env python
import os
import re
import inspect
import importlib
from lxml import etree

import click
import jinja2
from prompt_toolkit import (
    prompt
)
from prompt_toolkit.contrib.completers import WordCompleter
from prompt_toolkit.shortcuts import print_tokens

from botocore import xform_name
from botocore.session import Session
import boto3

from moto.core.responses import BaseResponse
from moto.core import BaseBackend
from implementation_coverage import (
    get_moto_implementation
)
from inflection import singularize

TEMPLATE_DIR = './template'

INPUT_IGNORED_IN_BACKEND = ['Marker', 'PageSize']
OUTPUT_IGNORED_IN_BACKEND = ['NextMarker']


def print_progress(title, body, color):
    click.secho('\t{}\t'.format(title), fg=color, nl=False)
    click.echo(body)


def select_service_and_operation():
    service_names = Session().get_available_services()
    service_completer = WordCompleter(service_names)
    service_name = prompt('Select service: ', completer=service_completer)
    if service_name not in service_names:
        click.secho('{} is not valid service'.format(service_name), fg='red')
        raise click.Abort()
    moto_client = get_moto_implementation(service_name)
    real_client = boto3.client(service_name, region_name='us-east-1')
    implemented = []
    not_implemented = []

    operation_names = [xform_name(op) for op in real_client.meta.service_model.operation_names]
    for op in operation_names:
        if moto_client and op in dir(moto_client):
            implemented.append(op)
        else:
            not_implemented.append(op)
    operation_completer = WordCompleter(operation_names)

    click.echo('==Current Implementation Status==')
    for operation_name in operation_names:
        check = 'X' if operation_name in implemented else ' '
        click.secho('[{}] {}'.format(check, operation_name))
    click.echo('=================================')
    operation_name = prompt('Select Operation: ', completer=operation_completer)

    if operation_name not in operation_names:
        click.secho('{} is not valid operation'.format(operation_name), fg='red')
        raise click.Abort()

    if operation_name in implemented:
        click.secho('{} is already implemented'.format(operation_name), fg='red')
        raise click.Abort()
    return service_name, operation_name


def get_lib_dir(service):
    return os.path.join('moto', service)

def get_test_dir(service):
    return os.path.join('tests', 'test_{}'.format(service))


def render_teamplte(tmpl_dir, tmpl_filename, context, service, alt_filename=None):
    is_test = True if 'test' in tmpl_dir else False
    rendered = jinja2.Environment(
        loader=jinja2.FileSystemLoader(tmpl_dir)
    ).get_template(tmpl_filename).render(context)

    dirname = get_test_dir(service) if is_test else get_lib_dir(service)
    filename = alt_filename or os.path.splitext(tmpl_filename)[0]
    filepath = os.path.join(dirname, filename)

    if os.path.exists(filepath):
        print_progress('skip creating', filepath, 'yellow')
    else:
        print_progress('creating', filepath, 'green')
        with open(filepath, 'w') as f:
            f.write(rendered)


def initialize_service(service, operation, api_protocol):
    """create lib and test dirs if not exist
    """
    lib_dir = os.path.join('moto', service)
    test_dir = os.path.join('tests', 'test_{}'.format(service))

    print_progress('Initializing service', service, 'green')

    service_class = boto3.client(service).__class__.__name__

    tmpl_context = {
        'service': service,
        'service_class': service_class
    }

    # initialize service directory
    if os.path.exists(lib_dir):
        print_progress('skip creating', lib_dir, 'yellow')
    else:
        print_progress('creating', lib_dir, 'green')
        os.makedirs(lib_dir)

    tmpl_dir = os.path.join(TEMPLATE_DIR, 'lib')
    for tmpl_filename in os.listdir(tmpl_dir):
        render_teamplte(
            tmpl_dir, tmpl_filename, tmpl_context, service
        )

    # initialize test directory
    if os.path.exists(test_dir):
        print_progress('skip creating', test_dir, 'yellow')
    else:
        print_progress('creating', test_dir, 'green')
        os.makedirs(test_dir)
    tmpl_dir = os.path.join(TEMPLATE_DIR, 'test')
    for tmpl_filename in os.listdir(tmpl_dir):
        alt_filename = 'test_{}.py'.format(service) if tmpl_filename == 'test_service.py.j2' else None
        render_teamplte(
            tmpl_dir, tmpl_filename, tmpl_context, service, alt_filename
        )

def to_upper_camel_case(s):
    return ''.join([_.title() for _ in s.split('_')])

def to_snake_case(s):
    s1 = re.sub('(.)([A-Z][a-z]+)', r'\1_\2', s)
    return re.sub('([a-z0-9])([A-Z])', r'\1_\2', s1).lower()


def get_function_in_responses(service, operation, protocol):
    """refers to definition of API in botocore, and autogenerates function
    You can see example of elbv2 from link below.
      https://github.com/boto/botocore/blob/develop/botocore/data/elbv2/2015-12-01/service-2.json
    """
    client = boto3.client(service)

    aws_operation_name = to_upper_camel_case(operation)
    op_model = client._service_model.operation_model(aws_operation_name)
    outputs = op_model.output_shape.members
    inputs = op_model.input_shape.members
    input_names = [to_snake_case(_) for _ in inputs.keys() if _ not in INPUT_IGNORED_IN_BACKEND]
    output_names = [to_snake_case(_) for _ in outputs.keys() if _ not in OUTPUT_IGNORED_IN_BACKEND]
    body = 'def {}(self):\n'.format(operation)

    for input_name, input_type in inputs.items():
        type_name = input_type.type_name
        if type_name == 'integer':
            arg_line_tmpl = '    {} = _get_int_param("{}")\n'
        elif type_name == 'list':
            arg_line_tmpl = '    {} = self._get_list_prefix("{}.member")\n'
        else:
            arg_line_tmpl = '    {} = self._get_param("{}")\n'
        body += arg_line_tmpl.format(to_snake_case(input_name), input_name)
    if output_names:
        body += '    {} = self.{}_backend.{}(\n'.format(','.join(output_names), service, operation)
    else:
        body += '    self.{}_backend.{}(\n'.format(service, operation)
    for input_name in input_names:
        body += '        {}={},\n'.format(input_name, input_name)

    body += '    )\n'
    if protocol == 'query':
        body += '    template = self.response_template({}_TEMPLATE)\n'.format(operation.upper())
        body += '    return template.render({})\n'.format(
            ','.join(['{}={}'.format(_, _) for _ in output_names])
        )
    elif protocol == 'json':
        body += '    # TODO: adjust reponse\n'
        body += '    return json.dumps({})\n'.format(','.join(['{}={}'.format(_, _) for _ in output_names]))
    return body


def get_function_in_models(service, operation):
    """refers to definition of API in botocore, and autogenerates function
    You can see example of elbv2 from link below.
      https://github.com/boto/botocore/blob/develop/botocore/data/elbv2/2015-12-01/service-2.json
    """
    client = boto3.client(service)
    aws_operation_name = to_upper_camel_case(operation)
    op_model = client._service_model.operation_model(aws_operation_name)
    inputs = op_model.input_shape.members
    outputs = op_model.output_shape.members
    input_names = [to_snake_case(_) for _ in inputs.keys() if _ not in INPUT_IGNORED_IN_BACKEND]
    output_names = [to_snake_case(_) for _ in outputs.keys() if _ not in OUTPUT_IGNORED_IN_BACKEND]
    if input_names:
        body = 'def {}(self, {}):\n'.format(operation, ', '.join(input_names))
    else:
        body = 'def {}(self)\n'
    body += '    # implement here\n'
    body += '    return {}\n'.format(', '.join(output_names))

    return body


def _get_subtree(name, shape, replace_list, name_prefix=[]):
    class_name = shape.__class__.__name__
    if class_name in ('StringShape', 'Shape'):
        t = etree.Element(name)
        if name_prefix:
            t.text = '{{ %s.%s }}' % (name_prefix[-1], to_snake_case(name))
        else:
            t.text = '{{ %s }}' % to_snake_case(name)
        return t
    elif class_name in ('ListShape', ):
        replace_list.append((name, name_prefix))
        t = etree.Element(name)
        t_member = etree.Element('member')
        t.append(t_member)
        for nested_name, nested_shape in shape.member.members.items():
            t_member.append(_get_subtree(nested_name, nested_shape, replace_list, name_prefix + [singularize(name.lower())]))
        return t
    raise ValueError('Not supported Shape')


def get_response_query_template(service, operation):
    """refers to definition of API in botocore, and autogenerates template
    Assume that response format is xml when protocol is query

    You can see example of elbv2 from link below.
      https://github.com/boto/botocore/blob/develop/botocore/data/elbv2/2015-12-01/service-2.json
    """
    client = boto3.client(service)
    aws_operation_name = to_upper_camel_case(operation)
    op_model = client._service_model.operation_model(aws_operation_name)
    result_wrapper = op_model.output_shape.serialization['resultWrapper']
    response_wrapper = result_wrapper.replace('Result', 'Response')
    metadata = op_model.metadata
    xml_namespace = metadata['xmlNamespace']

    # build xml tree
    t_root = etree.Element(response_wrapper,  xmlns=xml_namespace)

    # build metadata
    t_metadata = etree.Element('ResponseMetadata')
    t_request_id = etree.Element('RequestId')
    t_request_id.text = '1549581b-12b7-11e3-895e-1334aEXAMPLE'
    t_metadata.append(t_request_id)
    t_root.append(t_metadata)

    # build result
    t_result = etree.Element(result_wrapper)
    outputs = op_model.output_shape.members
    replace_list = []
    for output_name, output_shape in outputs.items():
        t_result.append(_get_subtree(output_name, output_shape, replace_list))
    t_root.append(t_result)
    xml_body = etree.tostring(t_root, pretty_print=True).decode('utf-8')
    xml_body_lines = xml_body.splitlines()
    for replace in replace_list:
        name = replace[0]
        prefix = replace[1]
        singular_name = singularize(name)

        start_tag = '<%s>' % name
        iter_name = '{}.{}'.format(prefix[-1], name.lower())if prefix else name.lower()
        loop_start = '{%% for %s in %s %%}' % (singular_name.lower(), iter_name)
        end_tag = '</%s>' % name
        loop_end = '{{ endfor }}'

        start_tag_indexes = [i for i, l in enumerate(xml_body_lines) if start_tag in l]
        if len(start_tag_indexes) != 1:
            raise Exception('tag %s not found in response body' % start_tag)
        start_tag_index = start_tag_indexes[0]
        xml_body_lines.insert(start_tag_index + 1, loop_start)

        end_tag_indexes = [i for i, l in enumerate(xml_body_lines) if end_tag in l]
        if len(end_tag_indexes) != 1:
            raise Exception('tag %s not found in response body' % end_tag)
        end_tag_index = end_tag_indexes[0]
        xml_body_lines.insert(end_tag_index, loop_end)
    xml_body = '\n'.join(xml_body_lines)
    body = '\n{}_TEMPLATE = """{}"""'.format(operation.upper(), xml_body)
    return body


def insert_code_to_class(path, base_class, new_code):
    with open(path) as f:
        lines = [_.replace('\n', '') for _ in f.readlines()]
    mod_path = os.path.splitext(path)[0].replace('/', '.')
    mod = importlib.import_module(mod_path)
    clsmembers = inspect.getmembers(mod, inspect.isclass)
    _response_cls = [_[1] for _ in clsmembers if issubclass(_[1], base_class) and _[1] != base_class]
    if len(_response_cls) != 1:
        raise Exception('unknown error, number of clsmembers is not 1')
    response_cls = _response_cls[0]
    code_lines, line_no = inspect.getsourcelines(response_cls)
    end_line_no = line_no + len(code_lines)

    func_lines = [' ' * 4 + _ for _ in new_code.splitlines()]

    lines = lines[:end_line_no] + func_lines + lines[end_line_no:]

    with open(path, 'w') as f:
        f.write('\n'.join(lines))


def insert_query_codes(service, operation):
    func_in_responses = get_function_in_responses(service, operation, 'query')
    func_in_models = get_function_in_models(service, operation)
    template = get_response_query_template(service, operation)

    # edit responses.py
    responses_path = 'moto/{}/responses.py'.format(service)
    print_progress('inserting code', responses_path, 'green')
    insert_code_to_class(responses_path, BaseResponse, func_in_responses)

    # insert template
    with open(responses_path) as f:
        lines = [_[:-1] for _ in f.readlines()]
    lines += template.splitlines()
    with open(responses_path, 'w') as f:
        f.write('\n'.join(lines))

    # edit models.py
    models_path = 'moto/{}/models.py'.format(service)
    print_progress('inserting code', models_path, 'green')
    insert_code_to_class(models_path, BaseBackend, func_in_models)

def insert_json_codes(service, operation):
    func_in_responses = get_function_in_responses(service, operation, 'json')
    func_in_models = get_function_in_models(service, operation)

    # edit responses.py
    responses_path = 'moto/{}/responses.py'.format(service)
    print_progress('inserting code', responses_path, 'green')
    insert_code_to_class(responses_path, BaseResponse, func_in_responses)

    # edit models.py
    models_path = 'moto/{}/models.py'.format(service)
    print_progress('inserting code', models_path, 'green')
    insert_code_to_class(models_path, BaseBackend, func_in_models)

@click.command()
def main():
    service, operation = select_service_and_operation()
    api_protocol = boto3.client(service)._service_model.metadata['protocol']
    initialize_service(service, operation, api_protocol)
    if api_protocol == 'query':
        insert_query_codes(service, operation)
    elif api_protocol == 'json':
        insert_json_codes(service, operation)
        pass
    else:
        print_progress('skip inserting code', 'api protocol "{}" is not supported'.format(api_protocol), 'yellow')

if __name__ == '__main__':
    main()