#!/usr/bin/env python3
# SPDX-License-Identifier: GPL-2.0-or-later
#
# Rewrite #include "x.h" to the folder x.h lives in under include/.
#
# include/ is split by subsystem -- arch/, core/, fs/, dev/, gfx/, net/,
# uapi/, ldls/ -- and every include names the folder, as Linux's do. Code
# written before the split, or by habit, says #include "proc.h"; this turns it
# into #include "core/proc.h". The folder each header is in is read from the
# tree, so moving a header and running this again is the whole procedure.
#
#   python3 tools/fix-includes.py FILE...       rewrite these files
#   python3 tools/fix-includes.py --modified    every file git says is changed
#   python3 tools/fix-includes.py --check FILE  print what would change, write
#                                               nothing; exit 1 if anything would
#
# Only quoted includes are touched. <errno.h> in a host tool is the system's
# errno.h and stays that way, and a file with a same-named header next to it
# keeps its own.

import os
import re
import subprocess
import sys

ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
INC = os.path.join(ROOT, "include")

where = {}
for sub in sorted(os.listdir(INC)):
    d = os.path.join(INC, sub)
    if os.path.isdir(d):
        for h in os.listdir(d):
            if h.endswith(".h"):
                where[h] = sub

pat = re.compile(r'(#\s*include\s*")((?:\.\./)*)(include/)?([A-Za-z0-9_]+\.h)"')


def fix(path, text):
    def one(m):
        pre, dots, incdir, h = m.groups()
        if h not in where:
            return m.group(0)
        if incdir:
            return '%s%sinclude/%s/%s"' % (pre, dots, where[h], h)
        if dots or os.path.exists(os.path.join(os.path.dirname(path), h)):
            return m.group(0)
        return '%s%s/%s"' % (pre, where[h], h)
    return pat.sub(one, text)


def modified():
    out = subprocess.run(["git", "-C", ROOT, "status", "--porcelain"],
                         capture_output=True, text=True, check=True).stdout
    files = []
    for line in out.splitlines():
        p = line[3:].split(" -> ")[-1]
        if p.endswith((".c", ".h", ".S", ".inc")):
            files.append(os.path.join(ROOT, p))
    return files


def main(argv):
    check = "--check" in argv
    args = [a for a in argv if not a.startswith("--")]
    files = modified() if "--modified" in argv else args
    if not files:
        print(__doc__ or "usage: fix-includes.py [--check] [--modified] FILE...")
        return 2
    changed = 0
    for f in files:
        if not os.path.isfile(f):
            continue
        with open(f, encoding="utf-8", errors="surrogateescape") as fh:
            old = fh.read()
        new = fix(f, old)
        if new == old:
            continue
        changed += 1
        if check:
            for a, b in zip(old.splitlines(), new.splitlines()):
                if a != b:
                    print("%s: %s  ->  %s" % (os.path.relpath(f), a.strip(), b.strip()))
        else:
            with open(f, "w", encoding="utf-8", errors="surrogateescape") as fh:
                fh.write(new)
            print("fixed", os.path.relpath(f))
    return 1 if check and changed else 0


if __name__ == "__main__":
    sys.exit(main(sys.argv[1:]))