// ai_transform_compile — 接收自然語言描述，輸出 transform stub
// Phase 0: 輸出 placeholder，Phase 2 再接 AI host function
//
//go:build tinygo

package main

import (
	"encoding/json"
	"io"
	"os"
	"strconv"
	"time"
)

type Input struct {
	Description  string          `json:"description"`
	ExampleInput json.RawMessage `json:"example_input"`
}

func main() {
	raw, err := io.ReadAll(os.Stdin)
	if err != nil {
		writeError("failed to read stdin: " + err.Error())
		return
	}
	var input Input
	if err := json.Unmarshal(raw, &input); err != nil {
		writeError("invalid input JSON: " + err.Error())
		return
	}
	if input.Description == "" {
		writeError("description 必填")
		return
	}

	transformID := "at-" + strconv.FormatInt(time.Now().UnixNano()/1e6, 10)

	out, _ := json.Marshal(map[string]interface{}{
		"success": true,
		"data": map[string]interface{}{
			"transform_id": transformID,
			"fn_preview":   "// AI generated\n// TODO: Phase 2 will implement AI-powered code generation\nreturn input;",
			"description":  input.Description,
		},
	})
	os.Stdout.Write(out)
}

func writeError(msg string) {
	out, _ := json.Marshal(map[string]interface{}{"success": false, "error": msg})
	os.Stdout.Write(out)
}