Attempt at Dart 2.0 Three.js interop with js_facade_gen

fix.py

#!/usr/bin/env python3

'''
Get ./js_facade_gen, and ./three.js
Comment out ./three.js/src/renderers/shaders/UniformsUtils.d.ts to avoid errors
Navigate to js_facade_gen
Under Zsh, run: node index.js --base-path=../three.js --destination=../dart-threejs ../three.js/src/**/*.ts
Navigate to ../dart-threejs
Add pubspec.yaml with package:js
Run this script twice to add the needed Dart SDK imports
'''

import os
import re


def find(name, root):
    '''
    Find filepath of file with [name] under [root].
    '''
    for path, dirs, files in os.walk(root):
        if name in files:
            return os.path.join(path, name)


# Some types must be imported from the Dart core
import_types = {
    'dart:html': [
        'MediaElement',
        'MediaStream',
        'VideoElement'
    ],
    'dart:web_audio': [
        'AudioContext',
        'GainNode',
        'PannerNode',
        'AudioBufferSourceNode'
    ],
    'dart:typed_data': [
        'Float32List',
        'Uint8List'
    ]
}

# Object name fixes (replace, by, exceptions).
change_names = [
    ('Array', 'List', ['ArrayCamera']),
    ('ListLike', 'List', []),
    ('HTML', '', [])
]

# Iterate all Dart files.
root = './lib'
for path, dirs, files in os.walk(root):
    for name in files:
        if name.endswith('.dart'):
            print(name)
            f = open(os.path.join(path, name), 'r+')
            whole_file = f.read()

            # Recognize need for extra imports.
            import_extra = []
            for lib, types in import_types.items():
                ns = lib.split(':')[1]
                for type in types:
                    if (f'{ns}.{type}' in whole_file) and not (lib in whole_file):
                        import_extra.append(lib)
                        break

            lines = whole_file.splitlines()
            f.seek(0)
            f.truncate()

            ln = 0
            for line in lines:
                ln += 1
                # Write extra import after first two lines.
                if ln == 3 and (len(import_extra) > 0):
                    f.write('\n')
                    for lib in import_extra:
                        ns = lib.split(':')[1]
                        f.write(f"import '{lib}' as {ns};\n")

                m1 = re.match(r'import "(\w+)\.dart"(.*);', line)
                m2 = re.match(r'import "(.*)"(.*);', line)
                m3 = re.match(r'export "(\w+)\.dart"(.*);', line)
                if m1:  # Expand path
                    fullPath = find(f'{m1.group(1)}.dart', root)
                    packagePath = fullPath.replace(root, 'package:threejs')
                    f.write(f"import '{packagePath}'{m1.group(2)};")
                    f.write('\n')
                elif m2:  # Vanity
                    f.write(f"import '{m2.group(1)}'{m2.group(2)};")
                    f.write('\n')
                elif m3:  # Expand path
                    fullPath = find(f'{m3.group(1)}.dart', root)
                    packagePath = fullPath.replace(root, 'package:threejs')
                    f.write(f"export '{packagePath}'{m3.group(2)};")
                    f.write('\n')
                else:
                    # Fix names.
                    for subs in change_names:
                        contains_exception = False
                        for exception in subs[2]:
                            if exception in line:
                                contains_exception = True
                                break
                        if not contains_exception:
                            line = line.replace(subs[0], subs[1])

                    # Add namespace for types that are imported from external
                    # packages (Dart SDK).
                    for lib, types in import_types.items():
                        ns = lib.split(':')[1]
                        for type in types:
                            # Check if type is used in this line.
                            if (f' {type}' in line or f'({type}' in line) and not (f'{ns}.{type}' in line):
                                # If the type is used twice in this line, it
                                # could also be used as name
                                # (`AudioContext get AudioContext`).
                                # Prefix only the first instance.
                                line = line.replace(
                                    f' {type}', f' {ns}.{type}', 1)
                                line = line.replace(
                                    f'({type}', f'({ns}.{type}', 1)

                    f.write(line)
                    f.write('\n')

            f.close()