package openrouter

import "context"

type ChatRequest struct {
	Model       string       `json:"model"`
	Messages    []Message    `json:"messages"`
	Modalities  []string     `json:"modalities,omitempty"`
	ImageConfig *ImageConfig `json:"image_config,omitempty"`
	Provider    *Provider    `json:"provider,omitempty"`
	TopP        *float64     `json:"top_p,omitempty"`
	Stream      bool         `json:"stream,omitempty"`
}

type ImageConfig struct {
	AspectRatio string `json:"aspect_ratio,omitempty"`
	ImageSize   string `json:"image_size,omitempty"`
}

type Provider struct {
	Order             []string `json:"order,omitempty"`
	Only              []string `json:"only,omitempty"`
	AllowFallbacks    *bool    `json:"allow_fallbacks,omitempty"`
	RequireParameters *bool    `json:"require_parameters,omitempty"`
}

type Message struct {
	Role    string        `json:"role"`
	Content []ContentPart `json:"content"`
}

type ContentPart struct {
	Type     string    `json:"type"`
	Text     string    `json:"text,omitempty"`
	ImageURL *ImageURL `json:"image_url,omitempty"`
}

type ImageURL struct {
	URL string `json:"url"`
}

type ChatResponse struct {
	Choices []Choice `json:"choices"`
}

type Choice struct {
	Message AssistantMessage `json:"message"`
}

type AssistantMessage struct {
	Content string          `json:"content"`
	Images  []ResponseImage `json:"images,omitempty"`
}

type ResponseImage struct {
	Type     string   `json:"type"`
	ImageURL ImageURL `json:"image_url"`
}

// Chat sends a chat completion request to the OpenRouter API.
func (c *Client) Chat(ctx context.Context, req ChatRequest) (*ChatResponse, error) {
	return c.chatCompletion(ctx, req)
}

func (c *Client) chatCompletion(ctx context.Context, req ChatRequest) (*ChatResponse, error) {
	var resp chatResponseRaw
	if err := c.do(ctx, "/chat/completions", req, &resp); err != nil {
		return nil, err
	}
	if resp.Error != nil {
		return nil, &APIError{Message: resp.Error.Message, Code: resp.Error.Code}
	}
	return &ChatResponse{Choices: resp.Choices}, nil
}

// APIError API 返回的业务错误
type APIError struct {
	Message string
	Code    any
}

func (e *APIError) Error() string {
	return "openrouter: api error: " + e.Message
}

// chatResponseRaw 包含 error 字段，仅用于内部解析
type chatResponseRaw struct {
	Choices []Choice `json:"choices"`
	Error   *struct {
		Message string `json:"message"`
		Code    any    `json:"code"`
	} `json:"error"`
}