WizardKit/scripts/wk/ui/tmux.py

"""WizardKit: tmux Functions"""
# vim: sts=2 sw=2 ts=2

import logging
import pathlib

from wk.exe import run_program
from wk.std import PLATFORM


# STATIC_VARIABLES
LOG = logging.getLogger(__name__)


# Functions
def capture_pane(pane_id=None):
  """Capture text from current or target pane, returns str."""
  cmd = ['tmux', 'capture-pane', '-p']
  if pane_id:
    cmd.extend(['-t', pane_id])

  # Capture and return
  proc = run_program(cmd, check=False)
  return proc.stdout.strip()


def clear_pane(pane_id=None):
  """Clear pane buffer for current or target pane."""
  commands = [
    ['tmux', 'send-keys', '-R'],
    ['tmux', 'clear-history'],
    ]
  if pane_id:
    commands = [[*cmd, '-t', pane_id] for cmd in commands]

  # Clear pane
  for cmd in commands:
    run_program(cmd, check=False)


def fix_layout(layout, forced=False):
  """Fix pane sizes based on layout."""
  resize_kwargs = []

  # Bail early
  if not (forced or layout_needs_fixed(layout)):
    # Layout should be fine
    return

  # Remove closed panes
  for data in layout.values():
    data['Panes'] = [pane for pane in data['Panes'] if poll_pane(pane)]

  # Update main panes
  resize_pane(height=999) # Set active pane too large and then adjust down
  for section, data in layout.items():
    if section == 'Workers':
      # Skip for now
      continue

    if 'height' in data:
      for pane_id in data['Panes']:
        resize_kwargs.append({'pane_id': pane_id, 'height': data['height']})
    if 'width' in data:
      for pane_id in data['Panes']:
        resize_kwargs.append({'pane_id': pane_id, 'width': data['width']})
  for kwargs in resize_kwargs:
    try:
      resize_pane(**kwargs)
    except RuntimeError:
      # Assuming pane was closed just before resizing
      pass

  # Update "group" panes widths
  for group in ('Title', 'Info'):
    num_panes = len(layout[group]['Panes'])
    if num_panes <= 1:
      continue
    width = int( (get_pane_size()[0] - (1 - num_panes)) / num_panes )
    for pane_id in layout[group]['Panes']:
      resize_pane(pane_id, width=width)
    if group == 'Title':
      # (re)fix Started pane
      #TODO: REstore: resize_pane(layout['Started']['Panes'][0], width=TMUX_SIDE_WIDTH)
      resize_pane(layout['Started']['Panes'][0], width=21)

  # Bail early
  if not (layout['Workers']['Panes'] and layout['Workers']['height']):
    return

  # Update worker heights
  worker_height = layout['Workers']['height']
  workers = layout['Workers']['Panes'].copy()
  num_workers = len(workers)
  avail_height = sum(get_pane_size(pane)[1] for pane in workers)
  avail_height += get_pane_size()[1] # Current pane
  # Check if window is too small
  if avail_height < (worker_height*num_workers) + 3:
    # Just leave things as-is
    return
  # Resize current pane
  resize_pane(height=avail_height-(worker_height*num_workers))
  # Resize bottom pane
  resize_pane(workers.pop(0), height=worker_height)
  # Resize the rest of the panes by adjusting the ones above them
  while len(workers) > 1:
    next_height = sum(get_pane_size(pane)[1] for pane in workers[:2])
    next_height -= worker_height
    resize_pane(workers[1], height=next_height)
    workers.pop(0)


def get_pane_size(pane_id=None):
  """Get current or target pane size, returns tuple."""
  cmd = ['tmux', 'display', '-p']
  if pane_id:
    cmd.extend(['-t', pane_id])
  cmd.append('#{pane_width} #{pane_height}')

  # Get resolution
  proc = run_program(cmd, check=False)
  width, height = proc.stdout.strip().split()
  width = int(width)
  height = int(height)

  # Done
  return (width, height)


def kill_all_panes(pane_id=None):
  """Kill all panes except for the current or target pane."""
  cmd = ['tmux', 'kill-pane', '-a']
  if pane_id:
    cmd.extend(['-t', pane_id])

  # Kill
  run_program(cmd, check=False)


def kill_pane(*pane_ids):
  """Kill pane(s) by id."""
  cmd = ['tmux', 'kill-pane', '-t']

  # Iterate over all passed pane IDs
  for pane_id in pane_ids:
    run_program(cmd+[pane_id], check=False)


def layout_needs_fixed(layout):
  """Check if layout needs fixed, returns bool."""
  needs_fixed = False

  # Check panes
  for data in layout.values():
    if 'height' in data:
      needs_fixed = needs_fixed or any(
        get_pane_size(pane)[1] != data['height'] for pane in data['Panes']
        )
    if 'width' in data:
      needs_fixed = needs_fixed or any(
        get_pane_size(pane)[0] != data['width'] for pane in data['Panes']
        )

  # TODO: Re-enable?
  ## Group panes
  #for group in ('Title', 'Info'):
  #  num_panes = len(layout[group]['Panes'])
  #  if num_panes <= 1:
  #    continue
  #  width = int( (get_pane_size()[0] - (1 - num_panes)) / num_panes )
  #  for pane in layout[group]['Panes']:
  #    needs_fixed = needs_fixed or abs(get_pane_size(pane)[0] - width) > 2

  # Done
  return needs_fixed


def poll_pane(pane_id):
  """Check if pane exists, returns bool."""
  cmd = ['tmux', 'list-panes', '-F', '#D']

  # Get list of panes
  proc = run_program(cmd, check=False)
  existant_panes = proc.stdout.splitlines()

  # Check if pane exists
  return pane_id in existant_panes


def prep_action(
    cmd=None, working_dir=None, text=None, watch_file=None, watch_cmd='cat'):
  """Prep action to perform during a tmux call, returns list.

  This will prep for running a basic command, displaying text on screen,
  or monitoring a file. The last option uses cat by default but can be
  overridden by using the watch_cmd.
  """
  action_cmd = []
  if working_dir:
    action_cmd.extend(['-c', working_dir])

  if cmd:
    # Basic command
    action_cmd.append(cmd)
  elif text:
    # Display text
    echo_cmd = ['echo']
    if PLATFORM == 'Linux':
      echo_cmd.append('-e')
    action_cmd.extend([
      'watch',
      '--color',
      '--exec',
      '--no-title',
      '--interval', '1',
      ])
    action_cmd.extend(echo_cmd)
    action_cmd.append(text)
  elif watch_file:
    # Monitor file
    prep_file(watch_file)
    if watch_cmd == 'cat':
      action_cmd.extend([
        'watch',
        '--color',
        '--no-title',
        '--interval', '1',
        'cat',
        ])
    elif watch_cmd == 'tail':
      action_cmd.extend(['tail', '-f'])
    action_cmd.append(watch_file)
  else:
    LOG.error('No action specified')
    raise RuntimeError('No action specified')

  # Done
  return action_cmd


def prep_file(path):
  """Check if file exists and create empty file if not."""
  path = pathlib.Path(path).resolve()
  try:
    path.touch(exist_ok=False)
  except FileExistsError:
    # Leave existing files alone
    pass


def resize_pane(pane_id=None, width=None, height=None, **kwargs):
  """Resize current or target pane.

  NOTE: kwargs is only here to make calling this function easier
        by dropping any extra kwargs passed.
  """
  cmd = ['tmux', 'resize-pane']

  # Safety checks
  if not (width or height):
    LOG.error('Neither width nor height specified')
    raise RuntimeError('Neither width nor height specified')

  # Finish building cmd
  if pane_id:
    cmd.extend(['-t', pane_id])
  if width:
    cmd.extend(['-x', str(width)])
  if height:
    cmd.extend(['-y', str(height)])

  # Resize
  run_program(cmd, check=False)


def split_window(
    lines=None, percent=None,
    behind=False, vertical=False,
    target_id=None, **action):
  """Split tmux window, run action, and return pane_id as str."""
  cmd = ['tmux', 'split-window', '-d', '-PF', '#D']

  # Safety checks
  if not (lines or percent):
    LOG.error('Neither lines nor percent specified')
    raise RuntimeError('Neither lines nor percent specified')

  # New pane placement
  if behind:
    cmd.append('-b')
  if vertical:
    cmd.append('-v')
  else:
    cmd.append('-h')
  if target_id:
    cmd.extend(['-t', target_id])

  # New pane size
  if lines:
    cmd.extend(['-l', str(lines)])
  elif percent:
    cmd.extend(['-p', str(percent)])

  # New pane action
  cmd.extend(prep_action(**action))

  # Run and return pane_id
  proc = run_program(cmd, check=False)
  return proc.stdout.strip()


def respawn_pane(pane_id, **action):
  """Respawn pane with action."""
  cmd = ['tmux', 'respawn-pane', '-k', '-t', pane_id]
  cmd.extend(prep_action(**action))

  # Respawn
  run_program(cmd, check=False)


def zoom_pane(pane_id=None):
  """Toggle zoom status for current or target pane."""
  cmd = ['tmux', 'resize-pane', '-Z']
  if pane_id:
    cmd.extend(['-t', pane_id])

  # Toggle
  run_program(cmd, check=False)


if __name__ == '__main__':
  print("This file is not meant to be called directly.")