// http_request — 發送任意 HTTP 請求，回傳 status + body
// 透過 host function 發出 HTTP，.wasm 本身不含網路 syscall
//
//go:build tinygo

package main

import (
	"encoding/json"
	"io"
	"os"
	"unsafe"
)

// host function 宣告（由 WASI shim 注入）
//
//go:wasmimport u6u http_request
func hostHttpRequest(
	urlPtr uintptr, urlLen uint32,
	methodPtr uintptr, methodLen uint32,
	headersPtr uintptr, headersLen uint32,
	bodyPtr uintptr, bodyLen uint32,
	outPtr uintptr, outLenPtr uintptr,
) uint32

type Input struct {
	URL     string          `json:"url"`
	Method  string          `json:"method"`
	Headers map[string]string `json:"headers"`
	Body    json.RawMessage `json:"body"`
}

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.URL == "" {
		writeError("url 必填")
		return
	}

	method := input.Method
	if method == "" {
		method = "GET"
	}

	// 序列化 headers
	headersJSON := "{}"
	if len(input.Headers) > 0 {
		b, _ := json.Marshal(input.Headers)
		headersJSON = string(b)
	}

	// body
	bodyStr := ""
	if len(input.Body) > 0 {
		bodyStr = string(input.Body)
	}

	// 呼叫 host function
	urlBytes := []byte(input.URL)
	methodBytes := []byte(method)
	headersBytes := []byte(headersJSON)
	bodyBytes := []byte(bodyStr)

	outBuf := make([]byte, 65536) // 64KB output buffer
	var outLen uint32

	result := hostHttpRequest(
		uintptr(unsafe.Pointer(&urlBytes[0])), uint32(len(urlBytes)),
		uintptr(unsafe.Pointer(&methodBytes[0])), uint32(len(methodBytes)),
		uintptr(unsafe.Pointer(&headersBytes[0])), uint32(len(headersBytes)),
		uintptr(unsafe.Pointer(&bodyBytes[0])), uint32(len(bodyBytes)),
		uintptr(unsafe.Pointer(&outBuf[0])), uintptr(unsafe.Pointer(&outLen)),
	)

	if result != 0 {
		writeError("HTTP request failed")
		return
	}

	responseStr := string(outBuf[:outLen])
	out, _ := json.Marshal(map[string]interface{}{
		"success": true,
		"data":    map[string]interface{}{"body": responseStr},
	})
	os.Stdout.Write(out)
}

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