#!/usr/bin/env fuchsia-vendored-python
# Copyright 2022 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.

#### CATEGORY=Code submission and review
### Print the gerrit review URL and attempts to open it in the user's default browser.

## Usage: fx cl

import subprocess
import sys
import os
import shlex
import configparser

def OpenInDefaultBrowser(url):
    """
    Attempts to open `url` in the default web browser.
    """

    if not sys.platform.startswith("linux"):
        return

    # To open a browser we can't use python's webbrowser module or even `xdg-open`, because
    # those requires certain environment variables to be set, and `fx` cleans up
    # the environment variables before running this script.
    # Instead, we look at the xdg-settings:
    # xdg-settings returns the name of a .desktop file (e.g. "google-chrome.desktop"),
    # that is located in "/usr/share/applications".
    # By parsing that .desktop file, we are able to obtain a command that launches the
    # default browser.
    try:
        # 1. Get the default browser's .desktop file name
        result = subprocess.run(
            ["xdg-settings", "get", "default-web-browser"],
            capture_output=True,
            text=True,
            check=True,
        )
        desktop_file_name = result.stdout.strip()

        # 2. Locate the .desktop file in standard XDG directory
        desktop_file_path = f"/usr/share/applications/{desktop_file_name}"

        # 3. Parse the .desktop file
        parser = configparser.ConfigParser(interpolation=None)

        # Read the file and get the 'Exec' command from the 'Desktop Entry' section
        parser.read(desktop_file_path)

        exec_command = None
        if parser.has_option("Desktop Entry", "Exec"):
            exec_command = parser.get("Desktop Entry", "Exec")
        else:
            print(f"Error: 'Exec' key not found in '{desktop_file_path}'")
            return

        # 4. Craft and execute the command to open the url in the browser
        # As per the "Desktop Entry Spec" (https://specifications.freedesktop.org/desktop-entry-spec/latest/exec-variables.html)
        # the exec command from the .desktop file can optionally contain %U or %u.
        # For example: "/usr/bin/google-chrome-stable %U".
        # Strip those optional arguments away to get the path to the executable.
        command_parts = shlex.split(exec_command)
        path_to_brower = command_parts[0]
        subprocess.run(
            [path_to_brower, url],
            capture_output=True,
            text=True,
            check=True,
        )

    except Exception as e:
        print(f"An unexpected error occurred: {e}")


def GetChangeId():
    """
    Attempts to obtain the change ID from the last commit.
    Returns an empty string if it fails.
    """
    change_id = None
    try:
        # Gets the description of the last commit
        commit_msg = subprocess.check_output(
            ["git", "log", "-1", '--format="%B"', "HEAD"], text=True
        )
        prefix = "Change-Id:"
        for l in commit_msg.splitlines():
            if l.startswith(prefix):
                change_id = l[len(prefix) :].strip()
    except:
        return None
    return change_id

# Opens the current CL in the web browser.
change_id = GetChangeId()
if change_id is None:
    print("No change ID found", file=sys.stderr)
    sys.exit(1)

url = f"https://fxrev.dev/{change_id}"
# If we can't manage to open the url at least we'll have printed the URL, which will
# be clickable in some terminals.
print(url)
OpenInDefaultBrowser(url)