// Package llm defines the provider abstraction and message types.
package llm

import "context"

type Role string

const (
	RoleSystem    Role = "system"
	RoleUser      Role = "user"
	RoleAssistant Role = "assistant"
	RoleTool      Role = "tool"
)

type ToolCall struct {
	ID        string `json:"id"`
	Name      string `json:"name"`
	Arguments string `json:"arguments"` // raw JSON
}

type Message struct {
	Role       Role       `json:"role"`
	Content    string     `json:"content"`
	ToolCalls  []ToolCall `json:"tool_calls,omitempty"`
	ToolCallID string     `json:"tool_call_id,omitempty"`
	Name       string     `json:"name,omitempty"`
}

// ToolSpec describes a callable tool using JSON Schema parameters.
type ToolSpec struct {
	Name        string         `json:"name"`
	Description string         `json:"description"`
	Parameters  map[string]any `json:"parameters"`
}

type Request struct {
	Messages []Message
	Tools    []ToolSpec
}

// Response is the final assembled assistant turn.
type Response struct {
	Content      string
	ToolCalls    []ToolCall
	FinishReason string
}

// DeltaFunc receives streamed text tokens. May be nil.
type DeltaFunc func(text string)

type Provider interface {
	Chat(ctx context.Context, req Request, onDelta DeltaFunc) (Response, error)
}