"""Kit manifest loading, slot inheritance, and which slots are worth showing."""

import os
import xml.etree.ElementTree as ET

import app_state


class MissingManifestError(Exception):
    """A kit the file needs has no manifest under the Sedona home folder.

    Raised rather than handled here, so the caller decides what to abandon: opening a
    file abandons the whole load, placing a palette component only abandons that
    component. Carrying the kit names lets either one name them in its own wording.
    """

    def __init__(self, kit_names, unresolved_type=None):
        self.kit_names = sorted(set(kit_names))
        self.unresolved_type = unresolved_type
        super().__init__(", ".join(self.kit_names))


def describe_missing_manifests(error):
    """The body of the dialog both callers show, pointing at the folder to check."""
    kit_list = "\n".join(f"    • {name}" for name in error.kit_names)
    home = app_state.SEDONA_HOME or "(not set)"

    lines = ["No manifest was found for:", "", kit_list, "", f"Sedona home folder:\n    {home}", ""]

    if error.unresolved_type:
        lines.append(
            f"Type '{error.unresolved_type}' inherits from a kit that is not in the "
            "file's schema block, so its slots cannot be resolved."
        )
        lines.append("")

    lines.append(
        "Check that the Sedona home folder is the right one and that it holds "
        "manifests/<kit>/<kit>-<checksum>.xml for each kit listed above. "
        "Preferences → Sedona home folder points it somewhere else."
    )
    return "\n".join(lines)


def read_summary_facet(slot_element):
    """Reads a slot's '@summary' facet. Absent means summary, matching manifest convention."""
    facets = slot_element.find("facets")
    if facets is None:
        return True
    for bool_facet in facets.findall("bool"):
        if bool_facet.get("name") == "summary":
            return (bool_facet.get("val", "true").strip().lower() != "false")
    return True


def get_slots_with_inheritance(type_name, kit_schemas):
    """Recursively resolves the slots for a given type by traversing its base chain."""
    if type_name not in kit_schemas:
        kit_prefix = type_name.split("::")[0] if "::" in type_name else type_name
        raise MissingManifestError([kit_prefix], unresolved_type=type_name)

    type_element = kit_schemas[type_name]
    base_type = type_element.get("base")

    resolved_slots = []
    if base_type:
        resolved_slots = get_slots_with_inheritance(base_type, kit_schemas)

    current_slots = []
    for slot in type_element.findall("slot"):
        current_slots.append({
            "name": slot.get("name"),
            "type": slot.get("type"),
            "default": slot.get("default", "false"),
            "flags": slot.get("flags", ""), # Capture visibility flags ('o' maps to operator/hidden)
            "summary": read_summary_facet(slot),
            "declared_id": int(slot.get("id"))
        })

    current_slots.sort(key=lambda s: s["declared_id"])
    resolved_slots.extend(current_slots)
    return resolved_slots


def compile_schema_registry(manifest_paths):
    """Loads and maps types across multiple kit files, ensuring all dependencies exist."""
    kit_schemas = {}

    for path in manifest_paths:
        try:
            tree = ET.parse(path)
            root = tree.getroot()
            kit_name = root.get("name")

            for type_tag in root.findall("type"):
                type_name = f"{kit_name}::{type_tag.get('name')}"
                kit_schemas[type_name] = type_tag
        except Exception as e:
            print(f"Error parsing manifest {path}: {e}")

    app_state.final_components_registry.clear()
    for type_name in kit_schemas.keys():
        flat_slots = get_slots_with_inheritance(type_name, kit_schemas)

        resolved_type_structure = []
        for sequence_id, slot_data in enumerate(flat_slots):
            resolved_type_structure.append({
                "slot_id": sequence_id,
                "name": slot_data["name"],
                "type": slot_data["type"],
                "default": slot_data["default"],
                "flags": slot_data["flags"],
                "summary": slot_data["summary"]
            })
        app_state.final_components_registry[type_name] = resolved_type_structure


def load_schema_kits_and_manifests():
    """Scans the schema block of the SAX file and maps/loads corresponding manifest definitions."""
    app_state.active_schema_kits.clear()
    if app_state.xml_root_element is None:
        return

    schema_elem = app_state.xml_root_element.find("schema")
    if schema_elem is None:
        return

    manifest_paths = []
    missing_kits = []
    for kit in schema_elem.findall("kit"):
        name = kit.get("name")
        checksum = kit.get("checksum")
        if not name:
            continue
        app_state.active_schema_kits[name] = checksum

        manifest_dir = os.path.join(app_state.SEDONA_HOME, "manifests", name)
        manifest_path = None

        if checksum:
            target_file = os.path.join(manifest_dir, f"{name}-{checksum}.xml")
            if os.path.exists(target_file):
                manifest_path = target_file

        if not manifest_path and os.path.exists(manifest_dir):
            files = [f for f in os.listdir(manifest_dir) if f.startswith(f"{name}-") and f.endswith(".xml")]
            if files:
                files.sort()
                manifest_path = os.path.join(manifest_dir, files[-1])

        if manifest_path:
            manifest_paths.append(manifest_path)
        else:
            # Every missing kit is collected before reporting, so one dialog names them
            # all rather than the user fixing them one reopen at a time.
            missing_kits.append(name)

    if missing_kits:
        raise MissingManifestError(missing_kits)

    compile_schema_registry(manifest_paths)


def get_slots_for_type(type_str, linked_slots=()):
    """
    Returns the slots worth painting for a given type, prefixed with double-digit
    index tags taken from the manifest so hidden rows leave gaps rather than renumber.

    Visibility, in order of precedence:
      - a linked slot is always shown, so its wire has a row to anchor to
      - '@summary false' hides the slot, even when it is runtime
      - runtime slots (no 'c' flag) are shown; they hold the live signal path
      - config slots that nothing links to are hidden as clutter
      - the 'o' (operator) flag hides a slot outright
    """
    if type_str not in app_state.final_components_registry:
        return []

    slots_list = []
    for slot_data in app_state.final_components_registry[type_str]:
        slot_name = slot_data["name"]
        if not slot_name:
            continue
        if "o" in slot_data["flags"]:
            continue

        is_linked = slot_name in linked_slots
        if not is_linked:
            if not slot_data.get("summary", True):
                continue
            if "c" in slot_data["flags"]:
                continue

        # Format to double digits (e.g., 00, 01, 02)
        padded_id = f"{slot_data['slot_id']:02d}"
        display_label = f"{padded_id}. {slot_name}"

        # Keep structural name unchanged for XML lookup inside comp, but pass display label
        slots_list.append((slot_name, display_label))

    return slots_list