#!/usr/bin/env python3
"""Transform any Python sample or example to Python NoteBook."""
import ast
import os
import sys
import re
from nbformat import v3
from nbformat import v4

input_file = sys.argv[1]
print(f'reading {input_file}')
with open(input_file) as fpin:
    text = fpin.read()

# Compute output file path.
output_file = input_file
output_file = output_file.replace('.py', '.ipynb')
# For example/python/foo.py -> example/notebook/examples/foo.ipynb
output_file = output_file.replace('examples/python',
                                  'examples/notebook/examples')
# For example/contrib/foo.py -> example/notebook/contrib/foo.ipynb
output_file = output_file.replace('examples/contrib',
                                  'examples/notebook/contrib')
# For ortools/*/samples/foo.py -> example/notebook/*/foo.ipynb
output_file = output_file.replace('ortools', 'examples/notebook')
output_file = output_file.replace('samples/', '')

nbook = v3.reads_py('')
nbook = v4.upgrade(nbook)  # Upgrade v3 to v4

print('Adding copyright cell...')
google = '##### Copyright 2022 Google LLC.'
nbook['cells'].append(v4.new_markdown_cell(source=google, id='google'))

print('Adding license cell...')
apache = '''Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
'''
nbook['cells'].append(v4.new_markdown_cell(source=apache, id='apache'))

print('Adding Title cell...')
basename = '# ' + os.path.basename(input_file).replace('.py', '')
nbook['cells'].append(v4.new_markdown_cell(source=basename, id='basename'))

print('Adding link cell...')
github_logo = 'https://raw.githubusercontent.com/google/or-tools/master/tools/github_32px.png'
github_path = 'https://github.com/google/or-tools/blob/master/' + input_file

colab_path = 'https://colab.research.google.com/github/google/or-tools/blob/master/' + output_file
colab_logo = 'https://raw.githubusercontent.com/google/or-tools/master/tools/colab_32px.png'
link = f'''<table align=\"left\">
<td>
<a href=\"{colab_path}\"><img src=\"{colab_logo}\"/>Run in Google Colab</a>
</td>
<td>
<a href=\"{github_path}\"><img src=\"{github_logo}\"/>View source on GitHub</a>
</td>
</table>'''
nbook['cells'].append(v4.new_markdown_cell(source=link, id='link'))

print('Adding ortools install cell...')
install_doc = ('First, you must install '
               '[ortools](https://pypi.org/project/ortools/) package in this '
               'colab.')
nbook['cells'].append(v4.new_markdown_cell(source=install_doc, id='doc'))
install_cmd = '!pip install ortools'
nbook['cells'].append(v4.new_code_cell(source=install_cmd, id='install'))

print('Adding code cell...')
all_blocks = ast.parse(text).body
print(f'number of bocks: {len(all_blocks)}')
line_start = [c.lineno - 1 for c in all_blocks]
line_start[0] = 0
lines = text.split('\n')

full_text = ''
for idx, (c_block, s, e) in enumerate(
        zip(all_blocks, line_start, line_start[1:] + [len(lines)])):
    print(f'block[{idx}]: {c_block}')
    c_text = '\n'.join(lines[s:e])
    # Clean boilerplate header and description
    if (idx == 0 and isinstance(c_block, ast.Expr)
            and isinstance(c_block.value, ast.Constant)):
        print('Adding description cell...')
        filtered_lines = lines[s:e]
        #filtered_lines = list(filter(lambda l: not l.startswith('#!'), lines[s:e]))
        filtered_lines = list(
            filter(lambda l: not re.search(r'^#!', l), filtered_lines))
        filtered_lines = list(
            filter(lambda l: not re.search(r'# \[START .*\]$', l),
                   filtered_lines))
        filtered_lines = list(
            filter(lambda l: not re.search(r'# \[END .*\]$', l),
                   filtered_lines))
        # TODO(mizux): Remove only copyright not all line with '^#'
        filtered_lines = list(
            filter(lambda l: not l.startswith(r'#'), filtered_lines))
        filtered_lines = [s.replace(r'"""', '') for s in filtered_lines]
        filtered_text = '\n'.join(filtered_lines)
        nbook['cells'].append(
            v4.new_markdown_cell(source=filtered_text, id='description'))
    # Remove absl app and flags import
    elif (isinstance(c_block, ast.ImportFrom) and c_block.module == 'absl'
          and c_block.names[0].name in ('flags', 'app')):
        print(f'Removing import {c_block.module}.{c_block.names[0].name}...')
    # Rewrite `FLAGS = flags.FLAGS`
    elif (isinstance(c_block, ast.Assign)
          and isinstance(c_block.targets[0], ast.Name)
          and c_block.targets[0].id == 'FLAGS'):
        print('Adding FLAGS class...')
        fixed_lines = ['class FLAGS: pass\n']
        full_text += '\n'.join(fixed_lines) + '\n'
    # Rewrite `flags.DEFINE_*(*)`
    elif (isinstance(c_block, ast.Expr) and isinstance(c_block.value, ast.Call)
          and isinstance(c_block.value.func, ast.Attribute)
          and c_block.value.func.value.id == 'flags'):
        print('Adding FLAGS field...')
        fixed_lines = []
        attr = c_block.value.func.attr
        if attr in ('DEFINE_integer', 'DEFINE_bool', 'DEFINE_string'):
            args = c_block.value.args
            #print(f'args: {args}')
            name = args[0].value
            if isinstance(args[1], ast.Constant):
                value = args[1].value
            elif isinstance(args[1], ast.UnaryOp):
                if isinstance(args[1].op, ast.USub):
                    value = -1 * int(args[1].operand.value)
                else:
                    print(f'unknow value operator: "{args[1].op}"')
                    sys.exit(2)
            else:
                print(f'unknow value: "{args[1]}"')
                sys.exit(2)
            comment = args[2].value

            print(f'FLAGS.{name} = \'{value}\' # {comment}')
            if attr in ('DEFINE_integer', 'DEFINE_bool'):
                fixed_lines.append(f'FLAGS.{name} = {value} # {comment}\n')
            else:
                fixed_lines.append(f'FLAGS.{name} = \'{value}\' # {comment}\n')
        else:
            print(f'unknow method: "{attr}"')
            sys.exit(2)
        full_text += '\n'.join(fixed_lines)
        # Add empty line after the last flags.DEFINE
        if e - 2 >= s and lines[e - 1] == '' and lines[e - 2] == '':
            full_text += '\n'
    # Unwrap __main__ function
    elif (isinstance(c_block, ast.If)
          and c_block.test.comparators[0].s == '__main__'):
        print('Unwrapping main function...')
        c_lines = lines[s + 1:e]
        # remove start and de-indent lines
        spaces_to_delete = c_block.body[0].col_offset
        fixed_lines = [
            n_line[spaces_to_delete:]
            if n_line.startswith(' ' * spaces_to_delete) else n_line
            for n_line in c_lines
        ]
        filtered_lines = fixed_lines
        filtered_lines = list(
            filter(lambda l: not re.search(r'# \[START .*\]$', l),
                   filtered_lines))
        filtered_lines = list(
            filter(lambda l: not re.search(r'# \[END .*\]$', l),
                   filtered_lines))
        filtered_lines = [
            re.sub(r'app.run\((.*)\)$', r'\1()', s) for s in filtered_lines
        ]
        full_text += '\n'.join(filtered_lines) + '\n'
    # Others
    else:
        print('Appending block...')
        filtered_lines = lines[s:e]
        filtered_lines = list(
            filter(lambda l: not re.search(r'# \[START .*\]$', l),
                   filtered_lines))
        filtered_lines = list(
            filter(lambda l: not re.search(r'# \[END .*\]$', l),
                   filtered_lines))
        full_text += '\n'.join(filtered_lines) + '\n'

nbook['cells'].append(v4.new_code_cell(source=full_text, id='code'))

jsonform = v4.writes(nbook) + '\n'

print(f'writing {output_file}')
with open(output_file, 'w') as fpout:
    fpout.write(jsonform)
