from typing import List

from pydantic import Field

from moonai.knowledge.source.base_knowledge_source import BaseKnowledgeSource


class StringKnowledgeSource(BaseKnowledgeSource):
    """A knowledge source that stores and queries plain text content using embeddings."""

    content: str = Field(...)

    def model_post_init(self, _):
        """Post-initialization method to validate content."""
        self.load_content()

    def load_content(self):
        """Validate string content."""
        if not isinstance(self.content, str):
            raise ValueError("StringKnowledgeSource only accepts string content")

    def add(self) -> None:
        """Add string content to the knowledge source, chunk it, compute embeddings, and save them."""
        new_chunks = self._chunk_text(self.content)
        self.chunks.extend(new_chunks)
        self.save_documents(metadata=self.metadata)

    def _chunk_text(self, text: str) -> List[str]:
        """Utility method to split text into chunks."""
        return [
            text[i : i + self.chunk_size]
            for i in range(0, len(text), self.chunk_size - self.chunk_overlap)
        ]
