Configuration management for Arcana.

Handles parsing and resolving configuration for embedders, chunkers, and other pluggable components.

Embedder Configuration

# Default: Local Bumblebee with bge-small-en-v1.5
config :arcana, embedder: :local

# Local with different model
config :arcana, embedder: {:local, model: "BAAI/bge-large-en-v1.5"}

# OpenAI (requires req_llm and OPENAI_API_KEY)
config :arcana, embedder: :openai
config :arcana, embedder: {:openai, model: "text-embedding-3-large"}

# Custom function
config :arcana, embedder: fn text -> {:ok, embedding} end

# Custom module implementing Arcana.Embedder behaviour
config :arcana, embedder: MyApp.CohereEmbedder
config :arcana, embedder: {MyApp.CohereEmbedder, api_key: "..."}

Chunker Configuration

# Default: text_chunker-based chunking
config :arcana, chunker: :default

# Default chunker with custom options
config :arcana, chunker: {:default, chunk_size: 512, chunk_overlap: 100}

# Custom function (receives text, opts; returns list of chunk maps)
config :arcana, chunker: fn text, _opts ->
  [%{text: text, chunk_index: 0, token_count: 10}]
end

# Custom module implementing Arcana.Chunker behaviour
config :arcana, chunker: MyApp.SemanticChunker
config :arcana, chunker: {MyApp.SemanticChunker, model: "..."}