# Released under the MIT License. See LICENSE for details.
#
"""Functionality related to code generation."""
from __future__ import annotations

import os
import json
from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from typing import List, Sequence, Optional, Any, Dict


def gen_flat_data_code(projroot: str, in_path: str, out_path: str,
                       var_name: str) -> None:
    """Generate a C++ include file from a Python file."""

    out_dir = os.path.dirname(out_path)
    if not os.path.exists(out_dir):
        os.makedirs(out_dir, exist_ok=True)

    with open(in_path, 'rb') as infileb:
        svalin = infileb.read()

    # JSON should do the trick for us here as far as char escaping/etc.
    # There's corner cases where it can differ from C strings but in this
    # simple case we shouldn't run into them.
    sval_out = f'const char* {var_name} ='

    # Store in ballistica's simple xor encryption to at least
    # slightly slow down hackers.
    sval = svalin

    sval1: Optional[bytes]
    sval1 = sval
    while sval1:
        sval_out += ' ' + json.dumps(sval1[:1000].decode())
        sval1 = sval1[1000:]
    sval_out += ';\n'

    pretty_path = os.path.abspath(out_path)
    if pretty_path.startswith(projroot + '/'):
        pretty_path = pretty_path[len(projroot) + 1:]
    print(f'Generating code: {pretty_path}')
    with open(out_path, 'w') as outfile:
        outfile.write(sval_out)


def gen_binding_code(projroot: str, in_path: str, out_path: str) -> None:
    """Generate binding.inc file."""

    out_dir = os.path.dirname(out_path)
    if not os.path.exists(out_dir):
        os.makedirs(out_dir, exist_ok=True)

    # Pull all lines in the embedded list and split into py and c++ names.
    with open(in_path) as infile:
        pycode = infile.read()

    # Double quotes causes errors.
    if '"' in pycode:
        raise Exception('bindings file can\'t contain double quotes.')
    lines = [
        l.strip().split(',  # ') for l in pycode.splitlines()
        if l.startswith('        ')
    ]
    if not all(len(l) == 2 for l in lines):
        raise Exception('malformatted data')

    # Our C++ code first execs our input as a string.
    ccode = ('{const char* bindcode = ' + repr(pycode).replace("'", '"') + ';')
    ccode += ('\nint result = PyRun_SimpleString(bindcode);\n'
              'if (result != 0) {\n'
              '  PyErr_PrintEx(0);\n'
              '  // Use a standard error to avoid a useless stack trace.\n'
              '  throw std::logic_error("Error fetching required Python'
              ' objects.");\n'
              '}\n')

    # Then it grabs the function that was defined and runs it.
    ccode += ('PyObject* bindvals = PythonCommand("get_binding_values()",'
              ' "<get_binding_values>")'
              '.RunReturnObj(true);\n'
              'if (bindvals == nullptr) {\n'
              '  // Use a standard error to avoid a useless stack trace.\n'
              '  throw std::logic_error("Error binding required Python'
              ' objects.");\n'
              '}\n')

    # Then it pulls the individual values out of the returned tuple.
    for i, line in enumerate(lines):
        ccode += ('SetObjCallable(ObjID::' + line[1] +
                  ', PyTuple_GET_ITEM(bindvals, ' + str(i) + '), true);\n')

    # Lastly it cleans up after itself.
    ccode += ('result = PyRun_SimpleString("del get_binding_values");\n'
              'if (result != 0) {\n'
              '  PyErr_PrintEx(0);\n'
              '  // Use a standard error to avoid a useless stack trace.\n'
              '  throw std::logic_error("Error cleaning up after Python'
              ' binding.");\n'
              '}\n'
              '}\n')
    pretty_path = os.path.abspath(out_path)
    if pretty_path.startswith(projroot + '/'):
        pretty_path = pretty_path[len(projroot) + 1:]
    print('Generating code: ' + pretty_path)
    with open(out_path, 'w') as outfile:
        outfile.write(ccode)