package common

import (
	"errors"
	"strings"

	"github.com/cloudwego/eino/schema"
)

type ImageInput struct {
	URLs []string
}

func BuildVisionMessages(systemPrompt string, userText string, images ImageInput) ([]*schema.Message, error) {
	if len(images.URLs) == 0 {
		return nil, errors.New("vision requires at least one image url")
	}
	parts := make([]schema.MessageInputPart, 0, 1+len(images.URLs))
	if strings.TrimSpace(userText) != "" {
		parts = append(parts, schema.MessageInputPart{Type: schema.ChatMessagePartTypeText, Text: userText})
	}
	for _, u := range images.URLs {
		if u == "" {
			continue
		}
		if !strings.HasPrefix(u, "http://") && !strings.HasPrefix(u, "https://") {
			continue
		}
		parts = append(parts, schema.MessageInputPart{Type: schema.ChatMessagePartTypeImageURL, Image: &schema.MessageInputImage{MessagePartCommon: schema.MessagePartCommon{URL: &u}, Detail: schema.ImageURLDetailHigh}})
	}
	if len(parts) == 0 {
		return nil, errors.New("vision inputs invalid: no text or valid image urls")
	}
	msgs := []*schema.Message{schema.SystemMessage(systemPrompt)}
	msgs = append(msgs, &schema.Message{Role: schema.User, UserInputMultiContent: parts})
	return msgs, nil
}