#!/usr/bin/env python3
#
# Copyright (c) 2022 Google LLC. All rights reserved.
#
# SPDX-License-Identifier: BSD-3-Clause

# quick hacky script to check patches if they are candidates for lts. it checks
# only the non-merge commits.

import pkg_resources
import os
import git
import re
import argparse
from io import StringIO
pkg_resources.require("unidiff>=0.7.4")
from unidiff import PatchSet

global_debug = False
def debug_print(*args, **kwargs):
    global global_var
    if global_debug:
        print(*args, **kwargs)

def contains_re(pf, tok):
    for hnk in pf:
        for ln in hnk:
            if ln.is_context:
                continue
            # here means the line is either added or removed
            txt = ln.value.strip()
            if tok.search(txt) is not None:
                return True

    return False

def process_ps(ps):
    score = 0

    cpu_tok = re.compile(CPU_PATH_TOKEN)
    doc_tok = re.compile(DOC_PATH_TOKEN)

    for pf in ps:
        if pf.is_binary_file or not pf.is_modified_file:
            continue
        if cpu_tok.search(pf.path) is not None:
            debug_print("* change found in cpu path:", pf.path);
            cpu_tok = re.compile(CPU_ERRATA_TOKEN)
            if contains_re(pf, cpu_tok):
                score = score + 1
                debug_print("    found", CPU_ERRATA_TOKEN)

        if doc_tok.search(pf.path) is not None:
            debug_print("* change found in macros doc path:", pf.path);
            doc_tok = re.compile(DOC_ERRATA_TOKEN)
            if contains_re(pf, doc_tok):
                score = score + 1
                debug_print("    found", DOC_ERRATA_TOKEN)

    return score

SUBJECT_TOKENS = r'fix\(cpus\)|revert\(cpus\)|fix\(errata\)|\(security\)'
CPU_PATH_TOKEN = r'lib/cpus/aarch(32|64)/.*\.S'
CPU_ERRATA_TOKEN = r'^report_errata ERRATA_'
DOC_PATH_TOKEN = r'docs/design/cpu-specific-build-macros.rst'
DOC_ERRATA_TOKEN = r'^^-\s*``ERRATA_'
SAMPLE_SIZE = 20

## TODO: for case like 921081049ec3 where we need to refactor first for security
#       patch to be applied then we should:
#       1. find the security patch
#       2. from that patch find CVE number if any
#       3. look for all patches that contain that CVE number in commit message

## TODO: similar to errata macros and rst file additions, we have CVE macros and rst file
#       additions. so we can use similar logic for that.

## TODO: for security we should look for CVE numbed regex match and if found flag it
def main():
    parser = argparse.ArgumentParser(prog="lts-triage.py", description="check patches for LTS candidacy")
    parser.add_argument("--repo", required=True, help="path to tf-a git repo")
    parser.add_argument("--branch", help="branch to check. default = integration", default="integration")
    parser.add_argument("--sample_size", help="how many patches to scan. default = 20", default=SAMPLE_SIZE)
    parser.add_argument("--debug", help="print debug logs", action="store_true")

    args = parser.parse_args()
    global global_debug
    global_debug = args.debug

    repo = git.Repo(args.repo)
    cnt = int(args.sample_size)

    # TODO: make sure that by iter_commits() we are traversing correctly in case of merge commits.
    for cmt in repo.iter_commits(args.branch):
        score = 0

        # don't process merge commits
        if len(cmt.parents) > 1:
            continue

        tok = re.compile(SUBJECT_TOKENS)
        if tok.search(cmt.summary) is not None:
            debug_print("## subject match")
            score = score + 1

        diff_text = repo.git.diff(cmt.hexsha + "~1", cmt.hexsha, ignore_blank_lines=True, ignore_space_at_eol=True)
        ps = PatchSet(StringIO(diff_text))
        debug_print("# score before process_ps:", score)
        score = score + process_ps(ps)
        debug_print("# score after process_ps:", score)

        print("{}:    {}".format(cmt.hexsha, score))

        cnt = cnt - 1
        if cnt == 0:
            break

if __name__ == '__main__':
    main()