"""Interactive device picker using questionary or CLI fallback."""

import sys
from typing import Iterable

from .pulse import Device


def _build_choices(devices: list[Device], preselected: set[str]) -> list:
    """Build questionary checkbox choices.

    questionary preselects via ``Choice(..., checked=True)``; passing a
    ``default`` list to ``checkbox`` is rejected by its validator.
    """
    import questionary

    return [
        questionary.Choice(
            f"[{'OUT' if d.kind == 'output' else 'IN'}] {d.description}  ({d.name})",
            value=d.name,
            checked=d.name in preselected,
        )
        for d in devices
    ]


def select_sources(devices: list[Device], preselected: Iterable[str] = ()) -> list[str]:
    """Interactively select audio sources.

    If questionary is available and stdin is a TTY, show a checkbox UI.
    Otherwise, show a numbered menu.

    Args:
        devices: List of available Device objects.
        preselected: Source names that should be pre-checked.

    Returns:
        List of selected source names in device order, deduplicated.

    Raises:
        RuntimeError: If non-TTY and user provides invalid input with no valid context.
    """
    preselected_set = set(preselected)

    # Try questionary UI first
    if sys.stdin.isatty():
        try:
            import questionary
        except ImportError:
            questionary = None

        if questionary is not None:
            try:
                selected = questionary.checkbox(
                    "Select audio sources to capture:",
                    choices=_build_choices(devices, preselected_set),
                ).ask()
            except KeyboardInterrupt:
                return list(preselected)

            if selected is None:
                # User aborted (Ctrl+C)
                return list(preselected)

            # Preserve device order
            result = []
            seen = set()
            for device in devices:
                if device.name in selected and device.name not in seen:
                    result.append(device.name)
                    seen.add(device.name)
            return result

    # CLI fallback: show numbered menu and read input
    print("\nAvailable audio sources:")
    for i, device in enumerate(devices, 1):
        kind_label = "OUT" if device.kind == "output" else "IN"
        marker = "✓" if device.name in preselected_set else " "
        print(f"  {marker} {i:2}. [{kind_label}] {device.description}")

    while True:
        prompt = (
            "\nSelect sources by number (space/comma-separated), "
            "'all', 'none', or blank to keep current:"
        )
        print(prompt)
        try:
            line = input("> ").strip()
        except EOFError:
            raise RuntimeError(
                "No TTY and EOF reached. Please provide --sources with comma-separated names "
                "(e.g. --sources 'alsa_input.usb-...,alsa_output.usb-...')"
            )

        if not line:
            # Keep preselected
            result = []
            seen = set()
            for device in devices:
                if device.name in preselected_set and device.name not in seen:
                    result.append(device.name)
                    seen.add(device.name)
            return result

        if line.lower() == "all":
            return [d.name for d in devices]

        if line.lower() == "none":
            return []

        # Parse indices
        try:
            # Accept space or comma as separator
            indices_str = line.replace(",", " ")
            indices = [int(x) for x in indices_str.split()]

            # Validate all indices first
            selected_indices = set()
            for idx in indices:
                if 1 <= idx <= len(devices):
                    selected_indices.add(idx)
                else:
                    print(
                        f"Invalid index: {idx}. "
                        f"Please enter numbers between 1 and {len(devices)}."
                    )
                    break
            else:
                # All indices were valid; return devices in device list order
                result = []
                seen = set()
                for i, device in enumerate(devices, 1):
                    if i in selected_indices and device.name not in seen:
                        result.append(device.name)
                        seen.add(device.name)
                return result

        except ValueError:
            print(
                "Invalid input. Please enter space/comma-separated numbers, "
                "'all', 'none', or blank."
            )