#!/usr/bin/env fuchsia-vendored-python

# Copyright 2020 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.

# After turning on -Wconversion globally, run a fuchsia build, but save
# the output.
#
#   $ fx build > /tmp/output 2>&1  # Can also use `ninja`
#   $ ./scripts/wconversion/wconversion-checks.py /tmp/output -i=-Wsign-conversion
#   2815 errors in unique locations
#   source files: 2073
#   header files: 741
#   other: 1
#   third party: 180
#   Counter({'-Wshorten-64-to-32': 1144, '-Wimplicit-int-conversion': 1038, ...})
#   No. of failed targets: 679

import os.path
import re
import sys

WERROR_PATTERN = re.compile("\[-Werror,(.+)\]")
TARGET_PATTERN = re.compile("\[(\d+)/\d+\]")


def parse_args():
    from argparse import ArgumentParser, FileType

    parser = ArgumentParser(
        description="Script for grabbing statistics on -Wconversion errors from an `fx build` or `ninja` output"
    )

    parser.add_argument(
        "infile", type=FileType("r"), help="File containing ninja logs"
    )

    # Ignore the `-W` because python will interpret it as an argument, even if it
    # is wrapped in single quotes in bash.
    parser.add_argument(
        "-i",
        "--ignore",
        action="append",
        default=[],
        help='Set of warnings to ignore ("-Wshorten-64-to-32", "-Wsign-conversion", etc.)',
    )

    return parser.parse_args()


def main():
    args = parse_args()
    ignored = set(args.ignore)

    failed_targets = set()
    errors = set()
    third_party = 0
    source_files = 0
    header_files = 0
    other = 0
    cur_target = None

    for line in args.infile:
        if TARGET_PATTERN.search(line):
            step, action, target = line.split(maxsplit=2)
            cur_target = target.strip()

        match = WERROR_PATTERN.search(line)
        if not match:
            continue

        err = match.group(1)
        if err in ignored:
            continue

        error_loc = line.find(": error: ")
        assert error_loc >= 0, "Could not find error line"

        path = line[:error_loc]
        path, line, col = path.split(":")
        line = int(line)
        col = int(col)

        errors.add((path, line, col, err))

        assert cur_target is not None, "Expected a target"
        if cur_target not in failed_targets:
            failed_targets.add(cur_target)

    for path, line, col, err in errors:
        if path.startswith("../../third_party/"):
            third_party += 1

        if path.endswith(".c") or path.endswith(".cc") or path.endswith(".cpp"):
            source_files += 1
        elif path.endswith(".h") or path.endswith(".hpp"):
            header_files += 1
        else:
            other += 1

    print(len(errors), "errors in unique locations")
    print("source files:", source_files)
    print("header files:", header_files)
    print("other:", other)

    print("third party:", third_party)

    # Distribution of errors
    from collections import Counter

    print(Counter((x[3] for x in errors)))

    print("No. of failed targets:", len(failed_targets))

    return 0


if __name__ == "__main__":
    sys.exit(main())