#!/usr/bin/env python3
# Copyright 2022 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
'''Utility that classifies the licenses in an SPDX file.'''

import argparse
import os
import subprocess
from fuchsia.tools.licenses.classification_types import *
from fuchsia.tools.licenses.spdx_types import *
from sys import stderr


def _log(*kwargs):
    print(*kwargs, file=stderr)


def _prepare_license_files(license_files_dir: str,
                           spdx_doc: SpdxDocument) -> Dict[str, str]:
    """Extract license texts in the spdx_doc into separate files"""

    # Reuse files for duplicate license texts to speed up classification
    file_by_unique_text: Dict[str, str] = {}

    license_files_by_id = {}
    for license in spdx_doc.extracted_licenses:
        id = license.license_id
        text = license.extracted_text
        if text in file_by_unique_text:
            file_path = file_by_unique_text[text]
        else:
            file_path = os.path.join(
                license_files_dir,
                f'license{len(file_by_unique_text.keys())}.txt')
            file_by_unique_text[text] = file_path
            with open(file_path, 'w') as license_file:
                license_file.write(license.extracted_text)
        license_files_by_id[id] = file_path

    _log(
        f"Identified {len(file_by_unique_text.keys())} unique license texts in"
        f" {len(spdx_doc.extracted_licenses)} extracted licenses: {file_by_unique_text.values()}"
    )

    return license_files_by_id


def _invoke_identify_license(
        identify_license_path: str, license_files_dir: str,
        license_files_by_id: Dict[str, str]) -> LicensesClassifications:
    """Invokes identify_license tool, returning an LicensesClassifications."""
    identify_license_output_path = 'identify_license_out.json'

    license_paths = sorted(list(set(license_files_by_id.values())))

    for path in [identify_license_path, license_files_dir] + license_paths:
        assert os.path.exists(path), f'{path} doesn\'t exist'

    with open(b258523163_workaround, 'w') as f:
        f.write(_UNENCUMBERED_LICENSE)

    command = [
        identify_license_path,
        '-headers',
        f'-json={identify_license_output_path}',
        license_files_dir,
        b258523163_workaround,
    ]

    _log(f'identify_license invocation = {command}')
    subprocess.check_output(command)

    assert os.path.exists(
        identify_license_output_path
    ), f"{identify_license_output_path} doesn't exist"

    classifications = LicensesClassifications.from_identify_license_output_json(
        identify_license_output_path, license_files_by_id)

    _log(
        f'Identified {classifications.identifications_count()} identifications in {classifications.licenses_count()} licenses'
    )

    return classifications


def _add_missing_identifications(
        spdx_doc: SpdxDocument,
        classifications: LicensesClassifications) -> LicensesClassifications:
    extra_classifications = []
    for l in spdx_doc.extracted_licenses:
        if l.license_id not in classifications.license_ids():
            identification = IdentifiedSnippet.create_empty(
                l.extracted_text_lines())
            extra_classifications.append(
                LicenseClassification(
                    license_id=l.license_id, identifications=[identification]))
    return classifications.add_classifications(extra_classifications)


def _load_override_rules(rule_paths: List[str]) -> ConditionOverrideRuleSet:
    rules = []
    for p in rule_paths:
        _log(f'Loading condition override rule {p}')
        rule_set = ConditionOverrideRuleSet.from_json(p)
        rules.extend(rule_set.rules)
    return ConditionOverrideRuleSet(rules)


def _apply_policy_and_overrides(
    classification: LicensesClassifications,
    conditions_policy_file_path: str,
    default_condition: str,
    policy_override_rules_file_paths: List[str],
    allowed_conditions: List[str],
) -> LicensesClassifications:
    conditions_policy = ConditionsPolicy.from_csv_file(
        conditions_policy_file_path, default_condition)
    classification = classification.set_conditions(conditions_policy)

    if policy_override_rules_file_paths:
        override_rules = _load_override_rules(policy_override_rules_file_paths)
        classification = classification.override_conditions(override_rules)

    classification = classification.verify_conditions(set(allowed_conditions))

    _log(
        f'{classification.failed_verifications_count()} of {classification.identifications_count()} identification failed verification'
    )

    return classification


def _print_verification_errors(classification: LicensesClassifications):
    verification_messages = classification.verification_errors()

    if verification_messages:
        for i in range(0, len(verification_messages)):
            _log(f"==========================")
            _log(f"VERIFICATION MESSAGE {i+1}/{len(verification_messages)}:")
            _log(f"==========================")
            _log(verification_messages[i])


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument(
        '--spdx_input',
        help='An SPDX json file containing all licenses to process.'
        'The output of @rules_fuchsia `fuchsia_licenses_spdx`',
        required=True,
    )
    parser.add_argument(
        '--identify_license_bin',
        help='Path to the identify_license binary. '
        'Expecting a binary with the same I/O as '
        'https://github.com/google/licenseidentify_license/tree/main/tools/identify_license',
        required=True,
    )
    parser.add_argument(
        '--conditions_policy',
        help=
        'A CSV file mapping license identification names to condition names',
        required=False,
        default=None,
    )
    parser.add_argument(
        '--policy_override_rules',
        help='Condition override rule files (JSON files)',
        # TODO(yaar): Document schema.
        nargs='*',
        required=False,
        default=[],
    )
    parser.add_argument(
        '--default_condition',
        help='Default condition for unmapped or unidentified licenses',
        required=False,
        default=None,
    )

    parser.add_argument(
        '--allowed_conditions',
        help='Conditions that are allowed',
        nargs='*',
        required=False,
        default=[],
    )

    parser.add_argument(
        '--fail_on_disallowed_conditions',
        help=
        'The tool will fail when classifications map to conditions not in the allowed list',
        type=bool,
        required=False,
        default=False,
    )

    parser.add_argument(
        '--output_file',
        help='Where to write the output json',
        required=True,
    )
    args = parser.parse_args()

    _log(f'Got these args {args}!')
    spdx_input = args.spdx_input

    _log(f'Reading license info from {spdx_input}!')
    spdx_doc = SpdxDocument.from_json(spdx_input)
    spdx_index = SpdxIndex.create(spdx_doc)

    licenses_dir = 'input_licenses'
    os.mkdir(licenses_dir)

    license_files_by_id = _prepare_license_files(licenses_dir, spdx_doc)

    classification = _invoke_identify_license(
        identify_license_path=args.identify_license_bin,
        license_files_dir=licenses_dir,
        license_files_by_id=license_files_by_id)

    classification = _add_missing_identifications(spdx_doc, classification)
    classification = classification.compute_identification_stats(spdx_index)
    classification = classification.add_licenses_information(spdx_index)

    classification = _apply_policy_and_overrides(
        classification,
        conditions_policy_file_path=args.conditions_policy,
        default_condition=args.default_condition,
        policy_override_rules_file_paths=args.policy_override_rules,
        allowed_conditions=args.allowed_conditions,
    )

    output_json_path = args.output_file
    _log(f'Writing classification into {output_json_path}!')
    classification.to_json(output_json_path)

    if args.fail_on_disallowed_conditions:
        if classification.failed_verifications_count() > 0:
            _log("ERROR: Licenses verification failed.")
            _print_verification_errors(classification)
            exit(-1)


# The text below is not a real license text.
_UNENCUMBERED_LICENSE = '''
This is free and unencumbered software released into the public domain.

Anyone is free to copy, modify, publish, use, compile, sell, or distribute
this software, either in source code form or as a compiled binary, for any
purpose, commercial or non-commercial, and by any means.

In jurisdictions that recognize copyright laws, the author or authors of this
software dedicate any and all copyright interest in the software to the public
domain. We make this dedication for the benefit of the public at large and to
the detriment of our heirs and

successors. We intend this dedication to be an overt act of relinquishment in
perpetuity of all present and future rights to this software under copyright
law.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

For more information, please refer to <http://unlicense.org/>
'''

if __name__ == '__main__':
    main()