package main

import (
	"encoding/base64"
	"errors"
	"fmt"
	"strings"
)

// imageUserMessage attaches pixels only to messages selected as new by a turn.
func imageUserMessage(store *ImageStore, text string) (any, error) {
	names := imageFiles(text)
	if len(names) == 0 {
		return modelUserMessage(text), nil
	}

	parts, err := imageParts(store, text, names)
	if err != nil {
		return nil, fmt.Errorf("make image message: %w", err)
	}

	return modelUserParts(parts), nil
}

// imageParts is the shared wire format for image messages and zoom results.
// Tool results use this list directly as function_call_output.output.
func imageParts(store *ImageStore, text string, names []string) ([]ModelInputPart, error) {
	parts := []ModelInputPart{{
		Type: "input_text",
		Text: text,
	}}
	for _, name := range names {
		if store == nil {
			return nil, errors.New("image store is not available")
		}

		data, err := store.Read(name)
		if err != nil {
			return nil, fmt.Errorf("read image part: %w", err)
		}

		mime := "image/" + strings.TrimPrefix(name[64:], ".")
		if strings.HasSuffix(name, ".jpg") {
			mime = "image/jpeg"
		}

		parts = append(parts, ModelInputPart{
			Type:     "input_image",
			ImageURL: "data:" + mime + ";base64," + base64.StdEncoding.EncodeToString(data),
		})
	}

	return parts, nil
}

// imageToolOutput leaves all results as text except zoom of one image message.
// Only the text goes to the log, never the data URLs.
func imageToolOutput(box *Toolbox, name, arguments, text string) (any, error) {
	if name != "zoom" || strings.HasPrefix(text, "error:") {
		return text, nil
	}

	var args ToolZoomArguments

	err := toolDecodeArguments(arguments, &args)
	if err != nil {
		return nil, fmt.Errorf("decode image zoom: %w", err)
	}

	if args.Name != nil || args.N != 1 {
		return text, nil
	}

	message, err := box.chat.Message(args.ID)
	if err != nil {
		return nil, fmt.Errorf("read image zoom: %w", err)
	}

	names := imageFiles(message.Text)
	if len(names) == 0 {
		return text, nil
	}

	parts, err := imageParts(box.images, text, names)
	if err != nil {
		return nil, fmt.Errorf("make image zoom: %w", err)
	}

	return parts, nil
}