from typing import List, Optional
from fastapi import HTTPException
from pydantic import BaseModel, Field

from models.presentation_structure_model import PresentationStructureModel


class SlideLayoutModel(BaseModel):
    id: str
    name: Optional[str] = None
    description: Optional[str] = None
    json_schema: dict


class PresentationLayoutModel(BaseModel):
    name: str
    ordered: bool = Field(default=False)
    slides: List[SlideLayoutModel]

    def get_slide_layout_index(self, slide_layout_id: str) -> int:
        for index, slide in enumerate(self.slides):
            if slide.id == slide_layout_id:
                return index
        raise HTTPException(
            status_code=404, detail=f"Slide layout {slide_layout_id} not found"
        )

    def to_presentation_structure(self):
        return PresentationStructureModel(
            slides=[index for index in range(len(self.slides))]
        )

    def to_string(self):
        message = f"## Presentation Layout\n\n"
        for index, slide in enumerate(self.slides):
            message += f"### Slide Layout: {index}: \n"
            message += f"- Name: {slide.name or slide.json_schema.get('title')} \n"
            message += f"- Description: {slide.description} \n\n"
        return message

    def to_catalog_string(self) -> str:
        """Richer layout catalog for LLM layout-selection prompts.

        Includes placeholder field names and their character limits so the LLM
        can make more informed layout choices based on content type.
        """
        lines = ["## Available Slide Layouts\n"]
        for index, slide in enumerate(self.slides):
            name = slide.name or slide.json_schema.get("title", f"Layout {index}")
            lines.append(f"### Layout {index}: {name}")
            if slide.description:
                lines.append(f"Purpose: {slide.description}")

            # Extract field names + constraints from json_schema
            props = slide.json_schema.get("properties", {})
            fields = []
            for field_name, field_def in props.items():
                if field_name.startswith("__"):
                    continue  # skip internal fields
                max_len = field_def.get("maxLength") or field_def.get("maxItems")
                constraint = f" (max {max_len})" if max_len else ""
                fields.append(f"{field_name}{constraint}")
            if fields:
                lines.append(f"Fields: {', '.join(fields)}")
            lines.append("")
        return "\n".join(lines)