import linecache
import traceback

from . import base_futures
from . import coroutines


def _task_repr_info(task):
 info = base_futures._future_repr_info(task)

 if task._must_cancel:
 # replace status
 info[0] = 'cancelling'

 coro = coroutines._format_coroutine(task._coro)
 info.insert(1, f'coro=<{coro}>')

 if task._fut_waiter is not None:
 info.insert(2, f'wait_for={task._fut_waiter!r}')
 return info


def _task_get_stack(task, limit):
 frames = []
 try:
 # 'async def' coroutines
 f = task._coro.cr_frame
 except AttributeError:
 f = task._coro.gi_frame
 if f is not None:
 while f is not None:
 if limit is not None:
 if limit <= 0:
 break
 limit -= 1
 frames.append(f)
 f = f.f_back
 frames.reverse()
 elif task._exception is not None:
 tb = task._exception.__traceback__
 while tb is not None:
 if limit is not None:
 if limit <= 0:
 break
 limit -= 1
 frames.append(tb.tb_frame)
 tb = tb.tb_next
 return frames


def _task_print_stack(task, limit, file):
 extracted_list = []
 checked = set()
 for f in task.get_stack(limit=limit):
 lineno = f.f_lineno
 co = f.f_code
 filename = co.co_filename
 name = co.co_name
 if filename not in checked:
 checked.add(filename)
 linecache.checkcache(filename)
 line = linecache.getline(filename, lineno, f.f_globals)
 extracted_list.append((filename, lineno, name, line))

 exc = task._exception
 if not extracted_list:
 print(f'No stack for {task!r}', file=file)
 elif exc is not None:
 print(f'Traceback for {task!r} (most recent call last):', file=file)
 else:
 print(f'Stack for {task!r} (most recent call last):', file=file)

 traceback.print_list(extracted_list, file=file)
 if exc is not None:
 for line in traceback.format_exception_only(exc.__class__, exc):
 print(line, file=file, end='')