#!/usr/bin/env vpython3
# Copyright 2024 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Redirects to the version of the metrics XML formatter in the Chromium tree."""

import gclient_paths
import os
import shutil
import subprocess
import sys


def GetMetricsDir(top_dir, path):
    top_dir = os.path.realpath(top_dir)
    metrics_xml_dirs = [
        os.path.join(top_dir, "tools", "metrics", "actions"),
        os.path.join(top_dir, "tools", "metrics", "dwa"),
        os.path.join(top_dir, "tools", "metrics", "histograms"),
        os.path.join(top_dir, "tools", "metrics", "structured"),
        os.path.join(top_dir, "tools", "metrics", "ukm"),
    ]
    abs_dirname = os.path.dirname(os.path.realpath(path))
    for xml_dir in metrics_xml_dirs:
        if abs_dirname.startswith(xml_dir):
            return xml_dir
    return None


def IsSupportedHistogramsXML(path):
    supported_xmls = set(
        [
            "histograms.xml",
            "enums.xml",
            "histogram_suffixes_list.xml",
        ]
    )
    return os.path.basename(path) in supported_xmls


def log(msg, verbose):
    if verbose:
        print(msg)


def FindMetricsXMLFormatterTool(path, verbose=False):
    """Returns a path to the metrics XML formatter executable."""
    top_dir = gclient_paths.GetPrimarySolutionPath()
    if not top_dir:
        log("Not executed in a Chromium checkout; skip formatting", verbose)
        return ""

    xml_dir = GetMetricsDir(top_dir, path)
    if not xml_dir:
        log(f"{path} is not a metric XML; skip formatting", verbose)
        return ""

    # Just to ensure that the given file is located in the current checkout
    # folder. If not, skip the formatting.
    if not os.path.realpath(path).startswith(os.path.realpath(top_dir)):
        log(
            f"{path} is not located in the current Chromium checkout; "
            "skip formatting",
            verbose,
        )
        return ""

    histograms_base_dir = os.path.join(
        top_dir, "tools", "metrics", "histograms"
    )
    if xml_dir.startswith(histograms_base_dir):
        # Skips the formatting, if the XML file is not one of the known types.
        if not IsSupportedHistogramsXML(path):
            log(
                f"{path} is not a supported histogram XML; skip formatting",
                verbose,
            )
            return ""

    return os.path.join(xml_dir, "pretty_print.py")


usage_text = """Usage: %s [option] filepath

Format a given metrics XML file with the metrics XML formatters in the Chromium
checkout. Noop, if executed out of a Chromium checkout.

Note that not all the options are understood by all the formatters.
Find the formatter binaries for all the options supported by each formatter.

positional arguments:
  filepath           if the path is not under tools/metrics,
                     no formatter will be run.

options:,
  -h, --help          show this help message and exit'
  --presubmit
  --diff"""


def _print_help():
    print(usage_text % sys.argv[0])


def main(args):
    path = next((arg for arg in args if not arg.startswith("-")), None)
    if not path:
        _print_help()
        return 0
    if not os.path.exists(path):
        raise FileNotFoundError(f"{path} does not exist.")

    tool = FindMetricsXMLFormatterTool(path, verbose=True)
    if not tool:
        # Fail (almost) silently.
        return 0

    subprocess.run(
        [
            shutil.which("vpython3"),
            tool,
        ]
        + args
    )
    return 0


if __name__ == "__main__":
    try:
        sys.exit(main(sys.argv[1:]))
    except KeyboardInterrupt:
        sys.stderr.write("interrupted\n")
        sys.exit(1)
