;;; llm-provider.scm - Provider abstraction for LLM backends
;;;
;;; BSD-3-Clause License
;;; Copyright (c) 2025, Rolando Abarca

(module llm-provider

(make-llm-provider
 llm-provider?
 llm-provider-name
 llm-provider-prepare-message
 llm-provider-build-payload
 llm-provider-call-api
 llm-provider-parse-response
 llm-provider-format-tool-result
 llm-provider-get-model-pricing
 llm-provider-extract-tool-calls
 ;; Optional capabilities (can be #f)
 llm-provider-generate-image
 llm-provider-transcribe-audio
 current-provider)

(import
 scheme
 chicken.base)

;;; ================================================================
;;; Provider Record Type (SRFI-9)
;;; ================================================================

;; Define the provider record type with all required operations
;; Each provider (OpenAI, Anthropic, Mistral, etc.) implements these procedures
(define-record-type <llm-provider>
  (make-llm-provider
   name                    ;; symbol: 'openai, 'anthropic, 'mistral
   prepare-message         ;; (message include-file?) -> provider-format message
   build-payload           ;; (messages tools model temp max-tokens) -> payload alist
   call-api                ;; (endpoint payload) -> response alist
   parse-response          ;; (response-data) -> normalized response
   format-tool-result      ;; (tool-call-id result) -> provider-format tool message
   get-model-pricing       ;; (model-name) -> pricing alist
   extract-tool-calls      ;; (response-message) -> list of (id name arguments)
   ;; Optional capabilities (can be #f if provider doesn't support)
   generate-image          ;; (prompt params-alist) -> alist with base64 data
   transcribe-audio)       ;; (file-path params-alist) -> string or alist
  llm-provider?
  (name llm-provider-name)
  (prepare-message llm-provider-prepare-message)
  (build-payload llm-provider-build-payload)
  (call-api llm-provider-call-api)
  (parse-response llm-provider-parse-response)
  (format-tool-result llm-provider-format-tool-result)
  (get-model-pricing llm-provider-get-model-pricing)
  (extract-tool-calls llm-provider-extract-tool-calls)
  (generate-image llm-provider-generate-image)
  (transcribe-audio llm-provider-transcribe-audio))

;;; ================================================================
;;; Current Provider Parameter
;;; ================================================================

;; Parameter for dynamic provider switching
;; Default is #f until a provider is set (typically OpenAI)
(define current-provider (make-parameter #f))

) ;; end module