// line_notify — 發送 LINE Notify 訊息
// 透過 host function 呼叫 LINE Notify API
//
//go:build tinygo

package main

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

//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 {
	Message string `json:"message"`
	Token   string `json:"token"`
}

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.Message == "" {
		writeError("message 必填")
		return
	}
	if input.Token == "" {
		writeError("token 必填")
		return
	}

	apiURL := "https://notify-api.line.me/api/notify"
	method := "POST"
	headers := map[string]string{
		"Authorization": "Bearer " + input.Token,
		"Content-Type":  "application/x-www-form-urlencoded",
	}
	headersJSON, _ := json.Marshal(headers)

	// form-encoded body
	body := "message=" + urlEncode(input.Message)

	urlBytes := []byte(apiURL)
	methodBytes := []byte(method)
	bodyBytes := []byte(body)

	outBuf := make([]byte, 4096)
	var outLen uint32

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

	if result != 0 {
		writeError("LINE Notify API 呼叫失敗")
		return
	}

	out, _ := json.Marshal(map[string]interface{}{
		"success": true,
		"data":    map[string]interface{}{"status": 200},
	})
	os.Stdout.Write(out)
}

// urlEncode — 簡易 URL 編碼（只處理常見字元）
func urlEncode(s string) string {
	var sb strings.Builder
	for _, c := range s {
		switch {
		case c >= 'A' && c <= 'Z', c >= 'a' && c <= 'z', c >= '0' && c <= '9',
			c == '-', c == '_', c == '.', c == '~':
			sb.WriteRune(c)
		case c == ' ':
			sb.WriteByte('+')
		default:
			// UTF-8 encode
			buf := []byte(string(c))
			for _, b := range buf {
				sb.WriteByte('%')
				sb.WriteByte("0123456789ABCDEF"[b>>4])
				sb.WriteByte("0123456789ABCDEF"[b&0xf])
			}
		}
	}
	return sb.String()
}

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