#!/usr/bin/env python3
import importlib
import inspect
import json
import os
import re
import shutil
import subprocess
import sys
import textwrap
import traceback
from pathlib import Path, PosixPath
from typing import Any, List, Tuple
from unittest.mock import patch

from ansi2html import Ansi2HTMLConverter
from devtools import PrettyFormat

THIS_DIR = Path(__file__).parent
DOCS_DIR = (THIS_DIR / '..').resolve()
EXAMPLES_DIR = DOCS_DIR / 'examples'
TMP_EXAMPLES_DIR = DOCS_DIR / '.tmp_examples'
MAX_LINE_LENGTH = int(re.search(r'max_line_length = (\d+)', (EXAMPLES_DIR / '.editorconfig').read_text()).group(1))
LONG_LINE = 50
pformat = PrettyFormat(simple_cutoff=LONG_LINE)


def to_string(value: Any) -> str:
    # attempt to build a pretty equivalent of the print output
    if isinstance(value, (dict, list, tuple, set)):
        return pformat(value)
    elif isinstance(value, str) and any(re.fullmatch(r, value, flags=re.DOTALL) for r in ['{".+}', r'\[.+\]']):
        try:
            obj = json.loads(value)
        except ValueError:
            # not JSON, not a problem
            pass
        else:
            s = json.dumps(obj)
            if len(s) > LONG_LINE:
                json.dumps(obj, indent=2)
            else:
                return s

    return str(value)


class MockPrint:
    def __init__(self, file: Path):
        self.file = file
        self.statements = []

    def __call__(self, *args, file=None, flush=None):
        frame = inspect.currentframe().f_back.f_back.f_back
        if sys.version_info >= (3, 8):
            frame = frame.f_back
        if not self.file.samefile(frame.f_code.co_filename):
            # happens when index_error.py imports index_main.py
            return
        s = ' '.join(map(to_string, args))

        self.statements.append((frame.f_lineno, s))


class MockPath(PosixPath):
    def __new__(cls, name, *args, **kwargs):
        if name == 'config.json':
            return cls._from_parts(name, *args, **kwargs)
        else:
            return Path.__new__(cls, name, *args, **kwargs)

    def read_text(self, *args, **kwargs) -> str:
        return '{"foobar": "spam"}'


def build_print_lines(s: str, max_len_reduction: int = 0):
    print_lines = []
    max_len = MAX_LINE_LENGTH - 3 - max_len_reduction
    for line in s.split('\n'):
        if len(line) > max_len:
            print_lines += textwrap.wrap(line, width=max_len)
        else:
            print_lines.append(line)
    return print_lines


def build_print_statement(line_no: int, s: str, lines: List[str]) -> None:
    indent = ''
    for back in range(1, 100):
        m = re.search(r'^( *)print\(', lines[line_no - back])
        if m:
            indent = m.group(1)
            break
    print_lines = build_print_lines(s, len(indent))

    if len(print_lines) > 2:
        text = textwrap.indent('"""\n{}\n"""'.format('\n'.join(print_lines)), indent)
    else:
        text = '\n'.join(f'{indent}#> {line}' for line in print_lines)
    lines.insert(line_no, text)


def all_md_contents() -> str:
    file_contents = []
    for f in DOCS_DIR.glob('**/*.md'):
        file_contents.append(f.read_text())
    return '\n\n\n'.join(file_contents)


def gen_ansi_output():

    conv = Ansi2HTMLConverter()

    input_file = EXAMPLES_DIR / 'devtools_main.py'
    os.environ['PY_DEVTOOLS_HIGHLIGHT'] = 'true'
    p = subprocess.run((sys.executable, str(input_file)), stdout=subprocess.PIPE, check=True, encoding='utf8')
    html = conv.convert(p.stdout, full=False).strip('\r\n')
    full_html = f'<div class="terminal">\n<pre class="terminal-content">\n{html}\n</pre>\n</div>'
    path = TMP_EXAMPLES_DIR / f'{input_file.stem}.html'
    path.write_text(full_html)
    print(f'generated ansi output to {path}')


dont_execute_re = re.compile(r'^# dont-execute\n', flags=re.M | re.I)
required_py_re = re.compile(r'^# *requires *python *(\d+).(\d+)', flags=re.M)


def should_execute(file_name: str, file_text: str) -> Tuple[str, bool]:
    if dont_execute_re.search(file_text):
        return dont_execute_re.sub('', file_text), False
    m = required_py_re.search(file_text)
    if m:
        if sys.version_info >= tuple(int(v) for v in m.groups()):
            return required_py_re.sub('', file_text), True
        else:
            v = '.'.join(m.groups())
            print(f'WARNING: {file_name} requires python {v}, not running')
            return required_py_re.sub(f'# requires python {v}, NOT EXECUTED!', file_text), False
    else:
        return file_text, True


def exec_examples():
    errors = []
    all_md = all_md_contents()
    new_files = {}
    os.environ.update({
        'my_auth_key': 'xxx',
        'my_api_key': 'xxx',
        'database_dsn': 'postgres://postgres@localhost:5432/env_db',
        'v0': '0',
        'sub_model': '{"v1": "json-1", "v2": "json-2"}',
        'sub_model__v2': 'nested-2',
        'sub_model__v3': '3',
        'sub_model__deep__v4': 'v4',
    })

    sys.path.append(str(EXAMPLES_DIR))
    for file in sorted(EXAMPLES_DIR.iterdir()):

        def error(desc: str):
            errors.append((file, desc))
            sys.stderr.write(f'error in {file.name}: {desc}\n')

        if not file.is_file():
            # __pycache__, maybe others
            continue

        if file.suffix != '.py':
            # just copy
            new_files[file.name] = file.read_text()
            continue

        if f'{{!.tmp_examples/{file.name}!}}' not in all_md:
            error('file not used anywhere')

        file_text = file.read_text('utf-8')
        if '\n\n\n\n' in file_text:
            error('too many new lines')
        if not file_text.endswith('\n'):
            error('no trailing new line')
        if re.search('^ *# *>', file_text, flags=re.M):
            error('contains comments with print output, please remove')

        file_text, execute = should_execute(file.name, file_text)
        if execute:
            no_print_intercept_re = re.compile(r'^# no-print-intercept\n', flags=re.M)
            print_intercept = not bool(no_print_intercept_re.search(file_text))
            if not print_intercept:
                file_text = no_print_intercept_re.sub('', file_text)

            if file.stem in sys.modules:
                del sys.modules[file.stem]
            mp = MockPrint(file)
            mod = None
            with patch('pathlib.Path', MockPath):
                with patch('builtins.print') as patch_print:
                    if print_intercept:
                        patch_print.side_effect = mp
                    try:
                        mod = importlib.import_module(file.stem)
                    except Exception:
                        tb = traceback.format_exception(*sys.exc_info())
                        error(''.join(e for e in tb if '/pydantic/docs/examples/' in e or not e.startswith('  File ')))

            if mod and not mod.__file__.startswith(str(EXAMPLES_DIR)):
                error(f'module path "{mod.__file__}" not inside "{EXAMPLES_DIR}", name may shadow another module?')

            lines = file_text.split('\n')

            to_json_line = '# output-json'
            if to_json_line in lines:
                lines = [line for line in lines if line != to_json_line]
                if len(mp.statements) != 1:
                    error('should have exactly one print statement')
                print_lines = build_print_lines(mp.statements[0][1])
                new_files[file.stem + '.json'] = '\n'.join(print_lines) + '\n'
            else:
                for line_no, print_string in reversed(mp.statements):
                    build_print_statement(line_no, print_string, lines)
        else:
            lines = file_text.split('\n')

        try:
            ignore_above = lines.index('# ignore-above')
        except ValueError:
            pass
        else:
            lines = lines[ignore_above + 1 :]

        try:
            ignore_below = lines.index('# ignore-below')
        except ValueError:
            pass
        else:
            lines = lines[:ignore_below]

        lines = '\n'.join(lines).split('\n')
        if any(len(l) > MAX_LINE_LENGTH for l in lines):
            error(f'lines longer than {MAX_LINE_LENGTH} characters')

        new_files[file.name] = '\n'.join(lines)

    if errors:
        print(f'\n{len(errors)} errors, not writing files\n')
        return 1

    if TMP_EXAMPLES_DIR.exists():
        shutil.rmtree(TMP_EXAMPLES_DIR)

    print(f'writing {len(new_files)} example files to {TMP_EXAMPLES_DIR}')
    TMP_EXAMPLES_DIR.mkdir()
    for file_name, content in new_files.items():
        (TMP_EXAMPLES_DIR / file_name).write_text(content, 'utf-8')
    gen_ansi_output()
    return 0


if __name__ == '__main__':
    sys.exit(exec_examples())