import re
import os
import sys
import json
import inspect

from markdown.extensions import Extension
from markdown.preprocessors import Preprocessor
from typing import Any, Dict, Optional, List
from yamole import YamoleParser
import markdown

import zerver.lib.api_test_helpers
from zerver.lib.openapi import get_openapi_fixture

MACRO_REGEXP = re.compile(r'\{generate_code_example(\(\s*(.+?)\s*\))*\|\s*(.+?)\s*\|\s*(.+?)\s*(\(\s*(.+)\s*\))?\}')
CODE_EXAMPLE_REGEX = re.compile(r'\# \{code_example\|\s*(.+?)\s*\}')

PYTHON_CLIENT_CONFIG = """
#!/usr/bin/env python3

import zulip

# Download ~/zuliprc-dev from your dev server
client = zulip.Client(config_file="~/zuliprc-dev")

"""

PYTHON_CLIENT_ADMIN_CONFIG = """
#!/usr/bin/env python

import zulip

# You need a zuliprc-admin with administrator credentials
client = zulip.Client(config_file="~/zuliprc-admin")

"""

def extract_python_code_example(source: List[str], snippet: List[str]) -> List[str]:
    start = -1
    end = -1
    for line in source:
        match = CODE_EXAMPLE_REGEX.search(line)
        if match:
            if match.group(1) == 'start':
                start = source.index(line)
            elif match.group(1) == 'end':
                end = source.index(line)
                break

    if (start == -1 and end == -1):
        return snippet

    snippet.extend(source[start + 1: end])
    snippet.append('    print(result)')
    snippet.append('\n')
    source = source[end + 1:]
    return extract_python_code_example(source, snippet)

def render_python_code_example(function: str, admin_config: Optional[bool]=False) -> List[str]:
    method = zerver.lib.api_test_helpers.TEST_FUNCTIONS[function]
    function_source_lines = inspect.getsourcelines(method)[0]

    if admin_config:
        config = PYTHON_CLIENT_ADMIN_CONFIG.splitlines()
    else:
        config = PYTHON_CLIENT_CONFIG.splitlines()

    snippet = extract_python_code_example(function_source_lines, [])

    code_example = []
    code_example.append('```python')
    code_example.extend(config)

    for line in snippet:
        # Remove one level of indentation and strip newlines
        code_example.append(line[4:].rstrip())

    code_example.append('```')

    return code_example

SUPPORTED_LANGUAGES = {
    'python': {
        'client_config': PYTHON_CLIENT_CONFIG,
        'admin_config': PYTHON_CLIENT_ADMIN_CONFIG,
        'render': render_python_code_example,
    }
}  # type: Dict[str, Any]

class APICodeExamplesGenerator(Extension):
    def extendMarkdown(self, md: markdown.Markdown, md_globals: Dict[str, Any]) -> None:
        md.preprocessors.add(
            'generate_code_example', APICodeExamplesPreprocessor(md, self.getConfigs()), '_begin'
        )


class APICodeExamplesPreprocessor(Preprocessor):
    def __init__(self, md: markdown.Markdown, config: Dict[str, Any]) -> None:
        super(APICodeExamplesPreprocessor, self).__init__(md)

    def run(self, lines: List[str]) -> List[str]:
        done = False
        while not done:
            for line in lines:
                loc = lines.index(line)
                match = MACRO_REGEXP.search(line)

                if match:
                    language = match.group(2)
                    function = match.group(3)
                    key = match.group(4)
                    argument = match.group(6)

                    if key == 'fixture':
                        if argument:
                            text = self.render_fixture(function, name=argument)
                        else:
                            text = self.render_fixture(function)
                    elif key == 'example':
                        if argument == 'admin_config=True':
                            text = SUPPORTED_LANGUAGES[language]['render'](function, admin_config=True)
                        else:
                            text = SUPPORTED_LANGUAGES[language]['render'](function)

                    # The line that contains the directive to include the macro
                    # may be preceded or followed by text or tags, in that case
                    # we need to make sure that any preceding or following text
                    # stays the same.
                    line_split = MACRO_REGEXP.split(line, maxsplit=0)
                    preceding = line_split[0]
                    following = line_split[-1]
                    text = [preceding] + text + [following]
                    lines = lines[:loc] + text + lines[loc+1:]
                    break
            else:
                done = True
        return lines

    def render_fixture(self, function: str, name: Optional[str]=None) -> List[str]:
        fixture = []

        # We assume that if the function we're rendering starts with a slash
        # it's a path in the endpoint and therefore it uses the new OpenAPI
        # format.
        if function.startswith('/'):
            path, method = function.rsplit(':', 1)
            fixture_dict = get_openapi_fixture(path, method, name)
        else:
            fixture_dict = zerver.lib.api_test_helpers.FIXTURES[function]

        fixture_json = json.dumps(fixture_dict, indent=4, sort_keys=True,
                                  separators=(',', ': '))

        fixture.append('```')
        fixture.extend(fixture_json.splitlines())
        fixture.append('```')

        return fixture

def makeExtension(*args: Any, **kwargs: str) -> APICodeExamplesGenerator:
    return APICodeExamplesGenerator(kwargs)