#!/usr/bin/env python3
# Copyright 2014 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""
usage: git map [-h] [--help] [<args>]

Enhances `git log --graph` view with information on commit branches + tags that
point to them. Items are colorized as follows:

  * Cyan    - Currently checked out branch
  * Green   - Local branch
  * Red     - Remote branches
  * Magenta - Tags
  * White   - Merge Base Markers
  * Blue background - The currently checked out commit
"""

import os
import sys

import gclient_utils
import git_common
import setup_color
import subprocess2
import from_third_party

colorama = from_third_party.import_module("colorama")

RESET = colorama.Fore.RESET + colorama.Back.RESET + colorama.Style.RESET_ALL
BRIGHT = colorama.Style.BRIGHT

BLUE_BACK = colorama.Back.BLUE + BRIGHT
BRIGHT_RED = colorama.Fore.RED + BRIGHT
CYAN = colorama.Fore.CYAN + BRIGHT
GREEN = colorama.Fore.GREEN + BRIGHT
MAGENTA = colorama.Fore.MAGENTA + BRIGHT
RED = colorama.Fore.RED
WHITE = colorama.Fore.WHITE + BRIGHT
YELLOW = colorama.Fore.YELLOW


def _print_help(outbuf):
    names = {
        "Cyan": CYAN,
        "Green": GREEN,
        "Magenta": MAGENTA,
        "Red": RED,
        "White": WHITE,
        "Blue background": BLUE_BACK,
    }
    msg = ""
    for line in __doc__.splitlines():
        for name, color in names.items():
            if name in line:
                msg += (
                    line.replace("* " + name, color + "* " + name + RESET)
                    + "\n"
                )
                break
        else:
            msg += line + "\n"
    outbuf.write(msg.encode("utf-8", "replace"))


def _color_branch(branch, all_branches, all_tags, current):
    if branch in (current, "HEAD -> " + current):
        color = CYAN
        current = None
    elif branch in all_branches:
        color = GREEN
        all_branches.remove(branch)
    elif branch in all_tags:
        color = MAGENTA
    elif branch.startswith("tag: "):
        color = MAGENTA
        branch = branch[len("tag: ") :]
    else:
        color = RED
    return color + branch + RESET


def _color_branch_list(branch_list, all_branches, all_tags, current):
    if not branch_list:
        return ""
    colored_branches = (GREEN + ", ").join(
        _color_branch(branch, all_branches, all_tags, current)
        for branch in branch_list
        if branch != "HEAD"
    )
    return GREEN + "(" + colored_branches + GREEN + ") " + RESET


def _parse_log_line(line):
    graph, branch_list, commit_date, subject = (
        line.decode("utf-8", "replace").strip().split("\x00")
    )
    branch_list = [] if not branch_list else branch_list.split(", ")
    commit = graph.split()[-1]
    graph = graph[: -len(commit)]
    return graph, commit, branch_list, commit_date, subject


def main(argv, outbuf):
    if "-h" in argv or "--help" in argv:
        _print_help(outbuf)
        return 0
    if gclient_utils.IsEnvCog():
        print(
            "map command is not supported in non-git environment.",
            file=sys.stderr,
        )
        return 1

    map_extra = git_common.get_config_list("depot_tools.map_extra")
    cmd = (
        [
            git_common.GIT_EXE,
            "log",
            git_common.root(),
            "--graph",
            "--branches",
            "--tags",
            "--color=always",
            "--date=short",
            "--pretty=format:%H%x00%D%x00%cd%x00%s",
        ]
        + map_extra
        + argv
    )

    log_proc = subprocess2.Popen(cmd, stdout=subprocess2.PIPE, shell=False)

    current = git_common.current_branch()
    all_tags = set(git_common.tags())
    all_branches = set(git_common.branches())
    if current in all_branches:
        all_branches.remove(current)

    merge_base_map = {}
    for branch in all_branches:
        merge_base = git_common.get_or_create_merge_base(branch)
        if merge_base:
            merge_base_map.setdefault(merge_base, set()).add(branch)

    for merge_base, branches in merge_base_map.items():
        merge_base_map[merge_base] = ", ".join(branches)

    try:
        for line in log_proc.stdout:
            if b"\x00" not in line:
                outbuf.write(line)
                continue

            graph, commit, branch_list, commit_date, subject = _parse_log_line(
                line
            )

            if "HEAD" in branch_list:
                graph = graph.replace("*", BLUE_BACK + "*")

            line = "{graph}{commit}\t{branches}{date} ~ {subject}".format(
                graph=graph,
                commit=BRIGHT_RED + commit[:10] + RESET,
                branches=_color_branch_list(
                    branch_list, all_branches, all_tags, current
                ),
                date=YELLOW + commit_date + RESET,
                subject=subject,
            )

            if commit in merge_base_map:
                line += "    <({})".format(
                    WHITE + merge_base_map[commit] + RESET
                )

            line += os.linesep
            outbuf.write(line.encode("utf-8", "replace"))
    except (BrokenPipeError, KeyboardInterrupt):
        pass
    return 0


if __name__ == "__main__":
    setup_color.init()
    with git_common.less() as less_input:
        sys.exit(main(sys.argv[1:], less_input))
