main.py

import os
import sys
import locale
import pygit2
import readchar
import subprocess
from urllib.parse import quote
from rich.markup import escape
from rich.console import Console
from datetime import datetime, timezone, timedelta
from zoneinfo import ZoneInfo, available_timezones

console = Console(highlight=False, soft_wrap=True)

timezones = {zone.lower(): zone for zone in available_timezones()}

time_format_str = os.getenv("TIME_FORMAT", "local")

if time_format_str.lower() == "original":
    locale.setlocale(locale.LC_TIME, "POSIX")
elif time_format_str.lower() == "local":
    locale.setlocale(locale.LC_TIME, "")
else:
    try:
        locale.setlocale(locale.LC_TIME, time_format_str)
    except Exception as e:
        console.print(f"[red]Error:[/red] {escape(str(e))}")

        format = "language[_territory][.codeset][@modifier]"
        setlocale_man_page = f"https://man7.org/linux/man-pages/man3/setlocale.3.html"

        console.print(
            f'TIME_FORMAT must be [green]"local"[/green] | [green]"original"[/green] | [green]"{escape(format)}"[/green]\n'
            f"See [cyan][link={setlocale_man_page}#:~:text={quote(format)}]{setlocale_man_page}#:~:text={escape(format)}[/link][/cyan]"
        )

        sys.exit(1)

time_zone_str = os.getenv("TIME_ZONE", "original")
time_zone_str_lower = time_zone_str.lower()

if time_zone_str_lower == "original":

    def date_time_string(epoch, offset):
        dt = datetime.fromtimestamp(epoch, timezone(timedelta(minutes=offset)))
        return dt.strftime("%c %z")

elif time_zone_str_lower == "local":

    def date_time_string(epoch, offset):
        dt = datetime.fromtimestamp(epoch, timezone(timedelta(minutes=offset)))
        return dt.astimezone().strftime("%c %z")

else:

    try:
        time_zone_exact_case = (
            timezones[time_zone_str_lower]
            if time_zone_str_lower in timezones
            else time_zone_str
        )
        time_zone = ZoneInfo(time_zone_exact_case)
    except Exception as e:
        console.print(f"[red]Error:[/red] {escape(str(e)[1:-1])}")

        tz_db_wiki = "https://en.wikipedia.org/wiki/List_of_tz_database_time_zones"

        console.print(
            f'TIME_ZONE must be [green]"original"[/green] | [green]"local"[/green] | [cyan]IANA Time Zone Identifier[/cyan]\n'
            f"See [cyan][link={tz_db_wiki}]{tz_db_wiki}[/link][/cyan]"
        )

        sys.exit(1)

    def date_time_string(epoch, offset):
        dt = datetime.fromtimestamp(epoch, timezone(timedelta(minutes=offset)))
        return dt.astimezone(time_zone).strftime("%c %z")


def main():
    dir = sys.argv[1] if len(sys.argv) > 1 else "."

    list_all = os.getenv("LIST_ALL", "0") == "1"

    try:
        if dir != ".":
            os.chdir(dir)
    except Exception as e:
        console.print(f"[red]Error:[/red] {escape(e.strerror)}: {escape(e.filename)}")
        return

    discovered_repo = pygit2.discover_repository(".")

    if not discovered_repo:
        console.print(
            f"[red]Error:[/red] No git repository found at {escape(os.getcwd())} or any parent directory"
        )
        return

    repo = pygit2.Repository(discovered_repo)

    commit = None
    try:
        commit = repo.head.peel()
    except Exception as e:
        console.print(f"[red]Error:[/red] {escape(str(e))}")
        return

    try:
        min_hash_len = len(
            subprocess.check_output(
                ["git", "rev-parse", "--short", "HEAD"], text=True
            ).strip()
        )
    except Exception as e:
        console.print(f"[red]Error:[/red] Unable to run git command. Is git installed?")
        return

    name = None
    email = None

    try:
        name = subprocess.check_output(
            ["git", "config", "user.name"], text=True
        ).strip()
    except Exception as e:
        pass
    try:
        email = subprocess.check_output(
            ["git", "config", "user.email"], text=True
        ).strip()
    except Exception as e:
        pass

    def show_commit(c):
        message = c.message.strip().splitlines()

        lines = []
        lines.append((escape(f"[{str(c.id)[:min_hash_len]}]"), escape(message[0])))

        author_name = (
            f"[yellow]{escape(c.author.name)}[/yellow]"
            if c.author.name == name
            else escape(c.author.name)
        )
        author_email = (
            f"[yellow]{escape(c.author.email)}[/yellow]"
            if c.author.email == email
            else escape(c.author.email)
        )
        committer_name = (
            f"[yellow]{escape(c.committer.name)}[/yellow]"
            if c.committer.name == name
            else escape(c.committer.name)
        )
        committer_email = (
            f"[yellow]{escape(c.committer.email)}[/yellow]"
            if c.committer.email == email
            else escape(c.committer.email)
        )
        lines.append(("[green]Author:[/green]", f"{author_name} <{author_email}>"))
        lines.append(
            (
                "[green]Author Date:[/green]",
                escape(date_time_string(c.author.time, c.author.offset)),
            )
        )
        if c.author.name != c.committer.name or c.author.email != c.committer.email:
            lines.append(
                ("[red]Committer:[/red]", f"{committer_name} <{committer_email}>")
            )
        if c.author.time != c.committer.time or c.author.offset != c.committer.offset:
            lines.append(
                (
                    "[red]Committer Date:[/red]",
                    escape(date_time_string(c.committer.time, c.committer.offset)),
                )
            )

        max_key_len = max(15, min_hash_len + 2)

        for key, value in commit.message_trailers.items():
            lines.append((f"[blue]{escape(key)}:[/blue]", escape(value)))
            max_key_len = max(max_key_len, len(key) + 1)

        for key, value in lines:
            spaces = " " * (max_key_len - console.measure(key).maximum)
            console.print(f"{key}{spaces} {value}")

        print()

    print()
    show_commit(commit)

    try:
        if list_all:
            while True:

                parents = commit.parent_ids
                if parents:
                    commit = repo[parents[0]]
                    show_commit(commit)
                else:
                    break

        else:
            while True:
                key = readchar.readkey()

                if key in (readchar.key.DOWN, readchar.key.SPACE, readchar.key.ENTER):
                    parents = commit.parent_ids
                    if parents:
                        commit = repo[parents[0]]
                        show_commit(commit)
                    else:
                        break

                elif key == readchar.key.ESC:
                    break

    except KeyboardInterrupt:
        pass


if __name__ == "__main__":
    main()