# by ChatGPT
import curses
import subprocess
import sys

def get_commits(filename):
    cmd = ['git', 'log', '--pretty=format:%h %ad %s', '--date=short', '--', filename]
    result = subprocess.run(cmd, capture_output=True, text=True)
    return result.stdout.splitlines()

def get_file_at_commit(commit_hash, filename):
    cmd = ['git', 'show', f'{commit_hash}:{filename}']
    result = subprocess.run(cmd, capture_output=True, text=True)
    return result.stdout.splitlines()

def main(stdscr, filename):
    curses.curs_set(0)
    curses.mousemask(curses.ALL_MOUSE_EVENTS)
    stdscr.keypad(True)

    commits = get_commits(filename)
    selected_commit = 0
    divider_col = 40
    focus = "left"
    scroll_offset = 0

    while True:
        stdscr.clear()
        height, width = stdscr.getmaxyx()

        # Draw commit list on the left
        for i in range(min(len(commits), height)):
            line = commits[i]
            if i == selected_commit and focus == "left":
                stdscr.attron(curses.A_REVERSE)
            stdscr.addnstr(i, 0, line, divider_col - 1)
            if i == selected_commit and focus == "left":
                stdscr.attroff(curses.A_REVERSE)

        # Draw vertical divider with box-drawing character
        for y in range(height):
            stdscr.addch(y, divider_col, '│')

        # Draw file content on the right
        if commits:
            commit_hash = commits[selected_commit].split()[0]
            file_lines = get_file_at_commit(commit_hash, filename)
            visible_lines = file_lines[scroll_offset:scroll_offset + height]
            for i, line in enumerate(visible_lines):
                stdscr.addnstr(i, divider_col + 2, line, width - divider_col - 3)

        stdscr.refresh()

        key = stdscr.getch()

        if key == curses.KEY_MOUSE:
            try:
                _, mx, my, _, bstate = curses.getmouse()
                if bstate & curses.BUTTON1_CLICKED:
                    focus = "left" if mx <= divider_col else "right"
            except curses.error:
                pass

        elif key in [ord('q'), 27]:
            break

        elif focus == "left":
            if key in [curses.KEY_DOWN, ord('j')]:
                if selected_commit < len(commits) - 1:
                    selected_commit += 1
                    scroll_offset = 0  # reset right pane scroll
            elif key in [curses.KEY_UP, ord('k')]:
                if selected_commit > 0:
                    selected_commit -= 1
                    scroll_offset = 0

        elif focus == "right":
            if key == curses.KEY_DOWN or key == ord('j'):
                if scroll_offset < max(0, len(file_lines) - height):
                    scroll_offset += 1
            elif key == curses.KEY_UP or key == ord('k'):
                if scroll_offset > 0:
                    scroll_offset -= 1
            elif key == curses.KEY_NPAGE:  # Page Down
                scroll_offset = min(scroll_offset + height, max(0, len(file_lines) - height))
            elif key == curses.KEY_PPAGE:  # Page Up
                scroll_offset = max(0, scroll_offset - height)

if __name__ == "__main__":
    if len(sys.argv) != 2:
        print("Usage: python git_time_machine.py path/to/file")
        sys.exit(1)
    filename = sys.argv[1]
    curses.wrapper(main, filename)