from __future__ import annotations

from .typing import PAD_INDEX

from .. import filtergraph as fgb

from ..utils import zip # pre-py310 compatibility

def resolve_connect_pad_indices(

left: fgb.abc.FilterGraphObject,

right: fgb.abc.FilterGraphObject,

from_left: list[PAD_INDEX | str | None],

to_right: list[PAD_INDEX | str | None],

from_right: list[PAD_INDEX | str | None],

to_left: list[PAD_INDEX | str | None],

resolve_omitted: bool,

) -> tuple[list[tuple[PAD_INDEX, PAD_INDEX]]]:

"""resolve and validate pad indices given for a filtergraph connect operation

:param left: transmitting filtergraph object

:param right: receiving filtergraph object

:param from_left: output pad ids or labels of `left` fg (feedforward link sources)

:param to_right: input pad ids or labels of the `right` fg (feedforward link destinations)

:param from_right: output pad ids or labels of the `right` fg (feedback link sources)

:param to_left: input pad ids or labels of this `left` fg (feedback destinations)

:param resolve_omitted: True to resolve the `None`'s in the pad indices. If False, any

incomplete pad index (those with `None`) will raise FiltergraphPadNotFoundError

:return: tuple pairs of filter pad indices to be paired. Each tuple pair consists of two pad indices: the

first is the source/output pad and the second is the destination/input pad.

"""

# make sure the pads to be linked are all pairable

try:

fwd_links = [(l, r) for l, r in zip(from_left, to_right, strict=True)]

except:

raise ValueError(

f"the number of pad indices in {from_left=} and {to_right=} must match."

)

try:

bwd_links = [(l, r) for l, r in zip(from_right, to_left, strict=True)]

except:

raise ValueError(

f"the number of pad indices in {from_right=} and {to_left=} must match."

)

# make sure all the link indices are 3-element tuples

fwd_links = [

(

left.resolve_pad_index(l, is_input=False, resolve_omitted=resolve_omitted),

right.resolve_pad_index(r, is_input=True, resolve_omitted=resolve_omitted),

)

for l, r in fwd_links

]

bwd_links = [

(

right.resolve_pad_index(r, is_input=False, resolve_omitted=resolve_omitted),

left.resolve_pad_index(l, is_input=True, resolve_omitted=resolve_omitted),

)

for r, l in bwd_links

]

return fwd_links, bwd_links