from __future__ import annotations

from pathlib import Path

from pptx import Presentation

from src.utils.validators import validate_template


class PlaceholderMapper:
    def __init__(self, template_path: str | Path | None = None):
        self.template_path = Path(template_path) if template_path else None
        self.presentation = None
        if self.template_path:
            self.load_template(self.template_path)

    def load_template(self, template_path: str | Path):
        validated_path = validate_template(template_path)
        self.template_path = validated_path
        self.presentation = Presentation(str(validated_path))
        return self.presentation

    def map_layout_types(self) -> list[str]:
        if not self.presentation:
            raise ValueError("Template not loaded.")
        return [layout.name for layout in self.presentation.slide_layouts]

    def map_placeholders(self, layout_index: int = 0) -> dict[str, str]:
        if not self.presentation:
            raise ValueError("Template not loaded.")

        layout = self.presentation.slide_layouts[layout_index]
        mapped = {}
        for placeholder in layout.placeholders:
            placeholder_name = getattr(placeholder, "name", None)
            placeholder_type = getattr(placeholder.placeholder_format, "type", None)
            if placeholder_name:
                mapped[str(placeholder_type).lower()] = placeholder_name
        return mapped


def choose_layout_index(
    layout_type: str,
    style_profile: dict,
    total_layouts: int,
) -> int:
    preferred = style_profile.get("preferred_layout_indices", {}) if style_profile else {}
    idx = preferred.get(layout_type, 1)
    if total_layouts <= 0:
        return 0
    return max(0, min(int(idx), total_layouts - 1))


def map_placeholders(template_placeholders: list[dict]) -> dict[str, list[str]]:
    """Backward-compatible helper."""
    mapped_placeholders: dict[str, list[str]] = {}
    for placeholder in template_placeholders:
        layout_type = placeholder.get("layout_type", "unknown")
        placeholder_name = placeholder.get("name", "")
        mapped_placeholders.setdefault(layout_type, []).append(placeholder_name)
    return mapped_placeholders


def get_placeholder_mapping(template: str | Path) -> list[dict[str, str]]:
    mapper = PlaceholderMapper(template)
    placeholders = mapper.map_placeholders(0)
    return [
        {"layout_type": "title", "name": placeholders.get("center title", "Title Placeholder")},
        {"layout_type": "content", "name": placeholders.get("object", "Content Placeholder")},
    ]