from __future__ import annotations

import warnings
from collections.abc import Hashable, Iterable
from functools import partial

import numpy as np

STAR = " * "
TAB = len(STAR) * " "

try:
    from rich.table import Table
except ImportError:
    Table = None  # type: ignore[assignment, misc]


def _format_missing_row(row: str, rich: bool) -> str:
    if rich:
        return f"[grey62]{row}[/grey62]"
    else:
        return row


def _format_varname(name, rich: bool):
    return name


def _format_subtitle(name: str, rich: bool) -> str:
    if rich:
        return f"[bold]{name}[/bold]"
    else:
        return name


def _format_cf_name(name: str, rich: bool) -> str:
    if rich:
        return f"[color(33)]{name}[/color(33)]"
    else:
        return name


def make_text_section(
    accessor,
    subtitle: str,
    attr: str | dict,
    dims=None,
    valid_keys=None,
    valid_values=None,
    default_keys=None,
    rich: bool = False,
):
    from .accessor import sort_maybe_hashable

    if dims is None:
        dims = []
    with warnings.catch_warnings():
        warnings.simplefilter("ignore")
        if isinstance(attr, str):
            try:
                vardict: dict[str, Iterable[Hashable]] = getattr(accessor, attr, {})
            except ValueError:
                vardict = {}
        else:
            assert isinstance(attr, dict)
            vardict = attr
    if valid_keys:
        vardict = {k: v for k, v in vardict.items() if k in valid_keys}

    # Sort keys if there aren't extra keys,
    # preserve default keys order otherwise.
    default_keys = [] if not default_keys else list(default_keys)
    extra_keys = list(set(vardict) - set(default_keys))
    ordered_keys = sorted(vardict) if extra_keys else default_keys
    vardict = {key: vardict[key] for key in ordered_keys if key in vardict}

    # Keep only valid values (e.g., coords or data_vars)
    if valid_values is not None:
        vardict = {
            key: set(value).intersection(valid_values)
            for key, value in vardict.items()
            if set(value).intersection(valid_values)
        }

    # Star for keys with dims only, tab otherwise
    rows = [
        (
            f"{STAR if dims and set(value) <= set(dims) else TAB}"
            f"{_format_cf_name(key, rich)}: "
            f"{_format_varname(sort_maybe_hashable(value), rich)}"
        )
        for key, value in vardict.items()
    ]

    # Append missing default keys followed by n/a
    if default_keys:
        missing_keys = [key for key in default_keys if key not in vardict]
        if missing_keys:
            rows.append(
                _format_missing_row(TAB + ", ".join(missing_keys) + ": n/a", rich)
            )
    elif not rows:
        rows.append(_format_missing_row(TAB + "n/a", rich))

    return _print_rows(subtitle, rows, rich)


def _print_rows(subtitle: str, rows: list[str], rich: bool):
    subtitle = f"{subtitle.rjust(20)}:"

    # Add subtitle to the first row, align other rows
    rows = [
        (
            _format_subtitle(subtitle, rich=rich) + row
            if i == 0
            else len(subtitle) * " " + row
        )
        for i, row in enumerate(rows)
    ]

    return "\n".join(rows) + "\n\n"


def _format_conventions(string: str, rich: bool):
    row = _print_rows(
        subtitle="Conventions",
        rows=[_format_cf_name(TAB + string, rich=rich)],
        rich=rich,
    )
    if rich:
        row = row.rstrip()
    return row


def _maybe_panel(textgen, title: str, rich: bool):
    if rich:
        from rich.panel import Panel

        kwargs = dict(
            expand=True,
            title_align="left",
            title=f"[bold][color(244)]{title}[/bold][/color(244)]",
            highlight=True,
            width=100,
        )
        if isinstance(textgen, Table):
            return Panel(textgen, padding=(0, 20), **kwargs)  # type: ignore[arg-type]
        else:
            text = "".join(textgen)
            return Panel(f"[color(241)]{text.rstrip()}[/color(241)]", **kwargs)  # type: ignore[arg-type]
    else:
        text = "".join(textgen)
        return title + ":\n" + text


def _get_bit_length(dtype):
    # Check if dtype is a numpy dtype, if not, convert it
    if not isinstance(dtype, np.dtype):
        dtype = np.dtype(dtype)

    # Calculate the bit length
    bit_length = 8 * dtype.itemsize

    return bit_length


def _unpackbits(mask, bit_length):
    # Ensure the array is a numpy array
    arr = np.asarray(mask)

    # Create an output array of the appropriate shape
    output_shape = arr.shape + (bit_length,)
    output = np.zeros(output_shape, dtype=np.uint8)

    # Unpack bits
    for i in range(bit_length):
        output[..., i] = (arr >> i) & 1

    return output[..., ::-1]


def _max_chars_for_bit_length(bit_length):
    """
    Find the maximum characters needed for a fixed-width display
    for integer values of a certain bit_length. Use calculation
    for signed integers, since it conservatively will always have
    enough characters for signed or unsigned.
    """
    # Maximum value for signed integers of this bit length
    max_val = 2 ** (bit_length - 1) - 1
    # Add 1 for the negative sign
    return len(str(max_val)) + 1


def find_set_bits(mask, value, repeated_masks, bit_length):
    bitpos = np.arange(bit_length)[::-1]
    if mask not in repeated_masks:
        if value == 0:
            return [-1]
        elif value is not None:
            return [int(np.log2(value))]
        else:
            return [int(np.log2(mask))]
    else:
        allset = bitpos[_unpackbits(mask, bit_length) == 1]
        setbits = bitpos[_unpackbits(mask & value, bit_length) == 1]
        return [b if abs(b) in setbits else -b for b in allset]


def _format_flags(accessor, rich):
    from .accessor import create_flag_dict

    try:
        flag_dict = create_flag_dict(accessor._obj)
    except ValueError:
        return _print_rows(
            "Flag Meanings", ["Invalid Mapping. Check attributes."], rich
        )

    masks = [m for m, _ in flag_dict.values()]
    repeated_masks = {m for m in masks if masks.count(m) > 1}
    excl_flags = [f for f, (m, v) in flag_dict.items() if m in repeated_masks]
    # indep_flags = [
    #     f
    #     for f, (m, _) in flag_dict.items()
    #     if m is not None and m not in repeated_masks
    # ]

    bit_length = _get_bit_length(accessor._obj.dtype)
    mask_width = _max_chars_for_bit_length(bit_length)
    key_width = max(len(key) for key in flag_dict)

    bit_text = []
    value_text = []
    for key, (mask, value) in flag_dict.items():
        if mask is None:
            bit_text.append("✗" if rich else "")
            value_text.append(str(value))
            continue
        bits = find_set_bits(mask, value, repeated_masks, bit_length)
        bitstring = ["."] * bit_length
        if bits == [-1]:
            continue
        else:
            for b in bits:
                bitstring[abs(b)] = _format_cf_name("1" if b >= 0 else "0", rich)
        text = "".join(bitstring[::-1])
        value_text.append(
            f"{mask:{mask_width}} & {value}"
            if key in excl_flags and value is not None
            else f"{mask:{mask_width}}"
        )
        bit_text.append(text if rich else f" / Bit: {text}")

    if rich:
        from rich import box
        from rich.table import Table

        table = Table(
            box=box.SIMPLE,
            width=None,
            title_justify="left",
            padding=(0, 2),
            header_style="bold color(244)",
        )

        table.add_column("Meaning", justify="left")
        table.add_column("Value", justify="right")
        table.add_column("Bits", justify="center")

        for val, bit, key in zip(value_text, bit_text, flag_dict, strict=False):
            table.add_row(_format_cf_name(key, rich), val, bit)

        return table

    else:
        rows = []
        for val, bit, key in zip(value_text, bit_text, flag_dict, strict=False):
            rows.append(
                f"{TAB}{_format_cf_name(key, rich):>{key_width}}: {TAB} {val} {bit}"
            )
        return _print_rows("Flag Meanings", rows, rich)


def _format_dsg_roles(accessor, dims, rich):
    from .criteria import _DSG_ROLES

    yield make_text_section(
        accessor,
        "CF Roles",
        "cf_roles",
        dims=dims,
        valid_keys=_DSG_ROLES,
        rich=rich,
    )


def _format_geometries(accessor, dims, rich):
    yield make_text_section(
        accessor,
        "CF Geometries",
        "geometries",
        dims=dims,
        # valid_keys=_DSG_ROLES,
        rich=rich,
    )


def _format_coordinates(accessor, dims, coords, rich):
    from .accessor import _AXIS_NAMES, _CELL_MEASURES, _COORD_NAMES

    section = partial(
        make_text_section, accessor=accessor, dims=dims, valid_values=coords, rich=rich
    )

    yield section(subtitle="CF Axes", attr="axes", default_keys=_AXIS_NAMES)
    yield section(
        subtitle="CF Coordinates", attr="coordinates", default_keys=_COORD_NAMES
    )
    yield section(
        subtitle="Cell Measures", attr="cell_measures", default_keys=_CELL_MEASURES
    )
    yield section(subtitle="Standard Names", attr="standard_names")
    yield section(subtitle="Bounds", attr="bounds")
    yield section(subtitle="Grid Mappings", attr="grid_mapping_names")


def _format_data_vars(accessor, data_vars, rich):
    from .accessor import _CELL_MEASURES

    section = partial(
        make_text_section,
        accessor=accessor,
        dims=None,
        valid_values=data_vars,
        rich=rich,
    )

    yield section(
        subtitle="Cell Measures", attr="cell_measures", default_keys=_CELL_MEASURES
    )
    yield section(subtitle="Standard Names", attr="standard_names")
    yield section(subtitle="Bounds", attr="bounds")
    yield section(subtitle="Grid Mappings", attr="grid_mapping_names")


def _format_sgrid(accessor, axes, rich):
    yield make_text_section(
        accessor,
        "CF role",
        "cf_roles",
        valid_keys=["grid_topology"],
        rich=rich,
    )

    yield make_text_section(
        accessor,
        "Axes",
        axes,
        accessor._obj.dims,
        valid_values=accessor._obj.dims,
        default_keys=axes.keys(),
        rich=rich,
    )