#!/usr/bin/env python3
import argparse, os, re, subprocess, sys

# Helpers

def run(cmd, **kw):
    """Run subprocess, capture output, raise on error."""
    return subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True, check=True, **kw)

def get_opened_depots():
    out = run(["p4", "opened"]).stdout.splitlines()
    # each line: //depot/.../File.cpp#rev - edit change ...
    return [line.split()[0].split("#")[0] for line in out if line]

def depot_to_client(path):
    # p4 where //depot/... -> "//depot/... //client/... C:/.../File.cpp"
    out = run(["p4", "where", path]).stdout.split()
    return out[2] if len(out) >= 3 else None

def build_diff(path):
    return run(["p4", "diff", "-du0", path]).stdout

# Main

def main():
    p = argparse.ArgumentParser(
        description="Simple Perforce wrapper for clang-format-diff.py with verbose output"
    )
    p.add_argument("files", nargs="*", help="Depot or local paths to format")
    p.add_argument("--verify", action="store_true",
                   help="Dry-run: report files needing formatting")
    p.add_argument("--diff-script", default="../../Engine/Extras/clang-format/clang-format-diff.py",
                   help="Path to LLVM clang-format-diff.py")
    p.add_argument("--clang-format", default="clang-format",
                   help="Path to clang-format binary")
    p.add_argument("-c", "--config-file", default=None,
                   help="Explicit path to .clang-format to use")
    p.add_argument("-v", "--verbose", action="store_true",
                   help="Show detailed operations and diffs")
    args = p.parse_args()
    verbose = args.verbose

    # determine list of targets
    if args.files:
        depots = [f.split("#")[0] for f in args.files]
    else:
        depots = get_opened_depots()
        if verbose:
            print("Opened files:")
            for c in depots:
                print(f"  - {c}")

    # filter .cpp/.h
    clients = []
    for d in depots:
        c = depot_to_client(d)
        if c and re.search(r'\.(cpp|h)$', c, re.IGNORECASE):
            clients.append(c)
    if not clients:
        print("No .cpp/.h files to format.")
        return 0
    if verbose:
        print("Formatting .h/.cpp:")
        for c in clients:
            print(f"  - {c}")

    status = 0
    for local in clients:
        diff = build_diff(local)
        if not diff:
            if verbose:
                print(f"No changes in: {local}")
            continue  # no changes

        if verbose:
            print(f"\n=== Processing: {local} ===")
            print("--- original diff ---")
            print(diff)

        cmd = [
            sys.executable, args.diff_script,
            f"-binary={args.clang_format}",
            "-style=file",
        ]

        # Build style argument: use explicit config when provided, else local .clang-format discovery
        style_arg = "-style=file"
        if args.config_file:
            cfg = os.path.abspath(args.config_file)
            style_arg = f"-style=file:{cfg}"
            if args.verbose:
                print(f"Using clang-format config: {cfg}")

        cmd = [
            sys.executable, args.diff_script,
            f"-binary={args.clang_format}",
            style_arg,
        ]

        if not args.verify:
             cmd.append("-i")
        if verbose:
            print("Running:", ' '.join(cmd))

        proc = subprocess.run(cmd, input=diff, text=True,
                              stdout=subprocess.PIPE,
                              stderr=subprocess.PIPE)

        if verbose and proc.stdout:
            print("--- clang-format-diff output ---")
            print(proc.stdout)
        if verbose and proc.stderr:
            print("--- errors ---", file=sys.stderr)
            print(proc.stderr, file=sys.stderr)

        if args.verify:
            print(f"*** NEEDS FORMATTING: {local}")
            status = 1
        else:
            if proc.returncode == 0:
                print(f"Patched diff-hunks in: {local}")
            else:
                # covers proc.returncode != 0
                print(f"Error running clang-format-diff on {local}", file=sys.stderr)
                print(proc.stderr, file=sys.stderr)
                status = max(status, proc.returncode)

    return status

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