# SPDX-FileCopyrightText: Freya Bruhin (The Compiler) <mail@qutebrowser.org>
#
# SPDX-License-Identifier: GPL-3.0-or-later

"""Utilities related to javascript interaction."""

from typing import Union
from collections.abc import Sequence

_InnerJsArgType = Union[None, str, bool, int, float]
_JsArgType = Union[_InnerJsArgType, Sequence[_InnerJsArgType]]


def string_escape(text: str) -> str:
    """Escape values special to javascript in strings.

    With this we should be able to use something like:
      elem.evaluateJavaScript("this.value='{}'".format(string_escape(...)))
    And all values should work.
    """
    # This is a list of tuples because order matters, and using OrderedDict
    # makes no sense because we don't actually need dict-like properties.
    replacements = (
        ('\\', r'\\'),  # First escape all literal \ signs as \\.
        ("'", r"\'"),   # Then escape ' and " as \' and \".
        ('"', r'\"'),   # (note it won't hurt when we escape the wrong one).
        ('\n', r'\n'),  # We also need to escape newlines for some reason.
        ('\r', r'\r'),
        ('\x00', r'\x00'),
        ('\ufeff', r'\ufeff'),
        # https://stackoverflow.com/questions/2965293/
        ('\u2028', r'\u2028'),
        ('\u2029', r'\u2029'),
    )
    for orig, repl in replacements:
        text = text.replace(orig, repl)
    return text


def to_js(arg: _JsArgType) -> str:
    """Convert the given argument so it's the equivalent in JS."""
    if arg is None:
        return 'undefined'
    elif isinstance(arg, str):
        return '"{}"'.format(string_escape(arg))
    elif isinstance(arg, bool):
        return str(arg).lower()
    elif isinstance(arg, (int, float)):
        return str(arg)
    elif isinstance(arg, list):
        return '[{}]'.format(', '.join(to_js(e) for e in arg))
    else:
        raise TypeError("Don't know how to handle {!r} of type {}!".format(
            arg, type(arg).__name__))


def assemble(module: str, function: str, *args: _JsArgType) -> str:
    """Assemble a javascript file and a function call."""
    js_args = ', '.join(to_js(arg) for arg in args)
    if module == 'window':
        parts = ['window', function]
    else:
        parts = ['window', '_qutebrowser', module, function]
    code = '"use strict";\n{}({});'.format('.'.join(parts), js_args)
    return code


def wrap_global(name: str, *sources: str) -> str:
    """Wrap a script using window._qutebrowser."""
    from qutebrowser.utils import jinja  # circular import
    template = jinja.js_environment.get_template('global_wrapper.js')
    return template.render(code='\n'.join(sources), name=name)
