# ========= Copyright 2026 @ Strukto.AI All Rights Reserved. =========
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ========= Copyright 2026 @ Strukto.AI All Rights Reserved. =========

from collections.abc import AsyncIterator

from mirage.accessor.base import Accessor
from mirage.cache.index import IndexCacheStore
from mirage.commands.builtin.aggregators import header_aggregate
from mirage.commands.builtin.generic.tail import tail as generic_tail
from mirage.commands.builtin.generic.tail import tail_multi
from mirage.commands.builtin.generic_bind.adapter import Builder, CommandIO
from mirage.commands.builtin.generic_bind.builders.common import split_readable
from mirage.commands.builtin.tail_helper import _parse_n, number_flag_error
from mirage.commands.builtin.utils.stream import _resolve_source
from mirage.io.types import ByteSource, IOResult
from mirage.types import PathSpec


async def tail(
    ops: CommandIO,
    accessor: Accessor,
    paths: list[PathSpec],
    *texts: str,
    stdin: AsyncIterator[bytes] | bytes | None = None,
    n: str | None = None,
    c: str | None = None,
    q: bool = False,
    v: bool = False,
    index: IndexCacheStore | None = None,
    **kwargs,
) -> tuple[ByteSource | None, IOResult]:
    num_err = number_flag_error("tail", n, c)
    if num_err is not None:
        return None, IOResult(exit_code=1, stderr=num_err.encode())
    n_int: int | None = None
    from_line: int | None = None
    if n is not None:
        lines, plus_mode = _parse_n(n)
        if plus_mode:
            from_line = lines
        else:
            n_int = lines
    c_int = int(c) if c is not None else None
    if paths and ops.is_mounted(accessor):
        paths = await ops.resolve_glob(accessor, paths, index)
        show_headers = (v or len(paths) > 1) and not q
        paths, err = await split_readable(ops, accessor, paths, index, "tail")
        io = IOResult(exit_code=1 if err else 0, stderr=err or None)
        if not paths:
            return None, io
        return tail_multi(paths,
                          read=ops.read_stream,
                          accessor=accessor,
                          index=index,
                          n=n_int,
                          c=c_int,
                          from_line=from_line,
                          show_headers=show_headers), io
    source = _resolve_source(stdin, "tail: missing operand")
    return generic_tail(source, n=n_int, c=c_int,
                        from_line=from_line), IOResult()


BUILDER = Builder('tail', tail, None, False, header_aggregate, read=True)