# Copyright (C) 2024 The Android Open Source Project
#
# 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.

upstream_git_repo = 'https://gitlab.com/kernel-firmware/linux-firmware.git'

# ##########################################################
# Parsing of linux-firmware WHENCE file
# ##########################################################

section_divider = '--------------------------------------------------------------------------'

# Handle paths that might be quoted or use backslashes to escape spaces.
#
# For some reason some of the paths listed in WHENCE seem to be quoted or
# use '\ ' to escape spaces in the files, even though this doesn't seem like
# it should be necessary. Handle it. This takes a path `p`. If it's surrounded
# by quotes it just strips the quotes off. If it isn't quoted but we see
# '\ ' we'll transform that to just simple spaces.
def unquote_path(p):
    if p.startswith('"') and p.endswith('"'):
        p = p[1:-1]
    else:
        p = p.replace('\\ ', ' ')

    return p

# Parse WHENCE from the upstream repository and return dict w/ info about files.
#
# This will read the upstream whence and return a dictionary keyed by files
# referenced in the upstream WHENCE (anything tagged 'File:', 'RawFile:', or
# 'Link:'). Values in the dictionary will be another dict that looks like:
#   {
#      'driver':  Name of the driver line associated with this file,
#      'kind':    The kind of file ('File', 'RawFile', or 'Link')
#      'license': If this key is present it's the text of the license; if this
#                 key is not present then the license is unknown.
#      'link':    Only present for 'kind' == 'Link'. This is where the link
#                 should point to.
#   }
def parse_whence(whence_text):
    file_info_map = {}

    driver = 'UNKNOWN'
    unlicensed_files = []
    license_text = None

    for line in whence_text.splitlines() + [section_divider]:
        # Take out trailing spaces / carriage returns
        line = line.rstrip()

        # Look for tags, which are lines that look like:
        #   tag: other stuff
        #
        # Tags always need to start the line and can't have any spaces in
        # them, which helps ID them as tags.
        #
        # Note that normally we require a space after the colon which keeps
        # us from getting confused when we're parsing license text that
        # has a URL. We special-case allow lines to end with a colon
        # since some tags (like "License:") are sometimes multiline tags
        # and the first line might just be blank.
        if ': ' in line or line.endswith(':'):
            tag, _, rest = line.partition(': ')
            tag = tag.rstrip(':')
            if ' ' in tag or '\t' in tag:
                tag = None
            else:
                rest = rest.lstrip()
        else:
            tag = None

        # Any new tag or a full separator ends a license.
        if line == section_divider or (tag and license_text):
            if license_text:
                for f in unlicensed_files:
                    # Clear out blank lines at the start and end
                    for i, text in enumerate(license_text):
                        if text:
                            break
                    for j, text in reversed(list(enumerate(license_text))):
                        if text:
                            break
                    license_text = license_text[i:j+1]

                    file_info_map[f]['license'] = '\n'.join(license_text)
            unlicensed_files = []
            license_text = None

            if line == section_divider:
                driver = 'UNKNOWN'

        if tag == 'Driver':
            driver = rest
        elif tag in ['File', 'RawFile', 'Link']:
            if tag == 'Link':
                rest, _, link_dest = rest.partition(' -> ')
                rest = rest.rstrip()
                link_dest = unquote_path(link_dest.lstrip())

            rest = unquote_path(rest)

            file_info_map[rest] = { 'driver': driver, 'kind': tag }
            if tag == 'Link':
                file_info_map[rest]['link'] = link_dest

            unlicensed_files.append(rest)
        elif tag in ['License', 'Licence']:
            license_text = [rest]
        elif license_text:
            license_text.append(line)

    return file_info_map

# Look at the license and see if it references other files.
#
# Many of the licenses in WHENCE refer to other files in the same directory.
# This will detect those and return a list of indirectly referenced files.
def find_indirect_files(license_text):
    license_files = []

    # Our regex match works better if there are no carriage returns, so
    # split everything else and join with spaces. All we care about is
    # detecting indirectly referenced files anyway.
    license_text_oneline = ' '.join(license_text.splitlines())

    # The only phrasing that appears present right now refer to one or two
    # other files and looks like:
    #   See <filename> for details
    #   See <filename1> and <filename2> for details
    #
    # Detect those two. More can be added later.
    pattern = re2.compile(r'.*[Ss]ee (.*) for details.*')
    matcher = pattern.matcher(license_text_oneline)
    if matcher.matches():
        for i in range(matcher.group_count()):
            license_files.extend(matcher.group(i + 1).split(' and '))

    return license_files

# ##########################################################
# Templates for generated files
# ##########################################################

# NOTES:
# - Right now license_type is always BY_EXCEPTION_ONLY. If this is
#   ever not right we can always add a lookup table by license_kind.
metadata_template = \
'''name: "linux-firmware-{name}"
description:
    "Contains an import of upstream linux-firmware for {name}."

third_party {{
  homepage: "{upstream_git_repo}"
  identifier {{
    type: "Git"
    value: "{upstream_git_repo}"
    primary_source: true
    version: "{version}"
  }}
  version: "{version}"
  last_upgrade_date {{ year: {year} month: {month} day: {day} }}
  license_type: BY_EXCEPTION_ONLY
}}
'''

# Automatically create the METADATA file under the directory `name`.
def create_metadata_file(ctx, name):
    output = metadata_template.format(
        name = name,
        year = ctx.now_as_string('yyyy'),
        month = ctx.now_as_string('M'),
        day = ctx.now_as_string('d'),
        version = ctx.fill_template('${GIT_SHA1}'),
        upstream_git_repo = upstream_git_repo,
    )

    ctx.write_path(ctx.new_path(name + '/METADATA'), output)

android_bp_template = \
'''// Copyright (C) {year} The Android Open Source Project
//
// 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.
//
// This file is autogenerated by copybara, please do not edit.

license {{
    name: "linux_firmware_{name}_license",
    // Private visibility because nothing links against this. The kernel just
    // asks for it to be loaded from disk by name.
    visibility: ["//visibility:private"],
    license_kinds: [{license_kinds}],
    license_text: [{license_files}],
}}

prebuilt_firmware {{
    name: "linux_firmware_{name}",
    licenses: ["linux_firmware_{name}_license"],
    srcs: [{fw_files}],
    dsts: [{fw_files}],
    vendor: true,
}}
'''

# Format the an array of strings to go into Android.bp
def format_android_bp_string_arr(a):
    if len(a) == 1:
        return '"%s"' % a[0]

    indent_per = '    '
    indent = indent_per * 2
    return '\n' + indent + \
           (',\n' + indent).join(['"%s"' % s for s in a]) + \
           ',\n' + indent_per

# Automatically create the Android.bp file under the directory `name`.
def create_android_bp_file(ctx, name, license_kind, fw_files):
    output = android_bp_template.format(
        name = name,
        license_kinds = format_android_bp_string_arr([license_kind]),
        license_files = format_android_bp_string_arr(['LICENSE']),
        fw_files = format_android_bp_string_arr(fw_files),
        year = ctx.now_as_string('yyyy'),
    )
    ctx.write_path(ctx.new_path(name + '/Android.bp'), output)

# Create the LICENSE file containing all relevant license text.
def create_license_file(ctx, name, license_text, license_files, fw_files):
    license_header_strs = []
    license_header_strs.append("For the files:")
    for f in fw_files:
        license_header_strs.append("- %s" % f)
    license_header_strs.append("\nThe license is as follows:\n")
    license_header_strs.append(license_text)

    # Even though the indrectly referenced files are copied to the directory
    # too, policy says to copy them into the main LICENSE file for easy
    # reference.
    license_strs = ['\n'.join(license_header_strs)]
    for f in license_files:
        license_strs.append("The text of %s is:\n\n%s" %
                            (f, ctx.read_path(ctx.new_path(name + '/' + f))))

    ctx.write_path(ctx.new_path(name + '/LICENSE'),
                   '\n\n---\n\n'.join(license_strs))

commit_message_template = \
'''IMPORT: {name}

Import firmware "{name}" using copybara.

Third-Party Import of: {upstream_git_repo}
Request Document: go/android3p
For CL Reviewers: go/android3p#reviewing-a-cl
For Build Team: go/ab-third-party-imports
Security Questionnaire: REPLACE WITH bug filed by go/android3p process
Bug: REPLACE WITH motivation bug
Bug: REPLACE WITH bug filed by go/android3p process
Test: None
'''

# Automatically set the commit message.
def set_commit_message(ctx, name):
    output = commit_message_template.format(
        name = name,
        upstream_git_repo = upstream_git_repo,
    )
    ctx.set_message(output)

# ##########################################################
# Main transformation
# ##########################################################

def _firmware_import_transform(ctx):
    name = ctx.params['name']
    license_kind = ctx.params['license_kind']
    expected_license_files = ctx.params['license_files']
    fw_files = ctx.params['fw_files']

    # We will read the WHENCE to validate that the license upstream lists for
    # the fw_files matches the license we think we have.
    whence_text = ctx.read_path(ctx.new_path('WHENCE'))
    file_info_map = parse_whence(whence_text)

    # To be a valid import then every fw_file we're importing must have the
    # same license. Validate that.
    license_text = file_info_map[fw_files[0]].get('license', '')
    if not license_text:
        ctx.console.error('Missing license for "%s"' % fw_files[0])

    bad_licenses = [f for f in fw_files
                    if file_info_map[f].get('license', '') != license_text]
    if bad_licenses:
        ctx.console.error(
            ('All files in a module must have a matching license. ' +
             'The license(s) for "%s" don\'t match the license for "%s".') %
            (', '.join(bad_licenses), fw_files[0])
        )

    for f in expected_license_files:
        ctx.run(core.move(f, name + '/' + f))

    for f in fw_files:
        if file_info_map[f]['kind'] == 'Link':
            dirname = (name + '/' + f).rsplit('/', 1)[0]
            ctx.create_symlink(ctx.new_path(name + '/' + f),
                               ctx.new_path(dirname + '/' + file_info_map[f]['link']))
        else:
            ctx.run(core.move(f, name + '/' + f))

    # Look for indirectly referenced license files since we'll need those too.
    license_files = find_indirect_files(license_text)

    # copybara required us to specify all the origin files. To make this work
    # firmware_import_workflow() requires the callers to provide the list of
    # indirectly referenced license files. Those should match what we detected.
    if tuple(sorted(license_files)) != tuple(sorted(expected_license_files)):
        ctx.console.error(
            ('Upstream WHENCE specified that licenses were %r but we expected %r.') %
            (license_files, expected_license_files)
        )

    create_license_file(ctx, name, license_text, license_files, fw_files)
    create_metadata_file(ctx, name)
    create_android_bp_file(ctx, name, license_kind, fw_files)
    set_commit_message(ctx, name)

    # We don't actually want 'WHENCE' in the destination but we need to read it
    # so we need to list it in the input files. We can't core.remove() since
    # that yells at us. Just replace it with some placeholder text.
    ctx.write_path(ctx.new_path('WHENCE'),
                   'Upstream WHENCE is parsed to confirm licenses; not copied here.\n')

# Create a workflow for the given files.
def firmware_import_workflow(name, license_kind, license_files, fw_files):
    return core.workflow(
        name = name,
        authoring = authoring.overwrite('linux-firmware importer <noreply@google.com>'),

        origin = git.origin(
            url = upstream_git_repo,
            ref = 'main',
        ),

        # The below is just a placeholder and will be overridden by command
        # line arguments passed by `run_copybara.sh`. The script is used
        # because our copybara flow is different than others. Our flow is:
        # 1. Add the new firmware import to copy.bara.sky and create a
        #    'ANDROID:' CL for this.
        # 2. Run copybara locally which creates an 'IMPORT:' CL. Validate
        #    that it looks OK.
        # 3. Upload both CLs in a chain and get review.
        destination = git.destination(
            url = 'please-use-run_copybara.sh',
            push = 'please-use-run_copybara.sh',
        ),

        origin_files = glob(
            include = license_files + fw_files + ['WHENCE'],
        ),
        destination_files = glob(
            include = [name + '/**'] + ['WHENCE'],
        ),
        mode = 'SQUASH',
        transformations = [
            core.dynamic_transform(
                impl = _firmware_import_transform,
                params = {
                    'name': name,
                    'license_kind': license_kind,
                    'license_files': license_files,
                    'fw_files': fw_files,
                },
            ),
        ]
    )

# ##########################################################
# Firmware that we manage, sorted alphabetically
# ##########################################################