// telegram — 透過 Telegram Bot 發送訊息
// 透過 host function 呼叫 Telegram Bot API
//
//go:build tinygo

package main

import (
	"encoding/json"
	"io"
	"os"
	"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 {
	ChatID   string `json:"chat_id"`
	Text     string `json:"text"`
	BotToken string `json:"bot_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.ChatID == "" {
		writeError("chat_id 必填")
		return
	}
	if input.Text == "" {
		writeError("text 必填")
		return
	}
	if input.BotToken == "" {
		writeError("bot_token 必填")
		return
	}

	apiURL := "https://api.telegram.org/bot" + input.BotToken + "/sendMessage"
	method := "POST"
	headers := map[string]string{
		"Content-Type": "application/json",
	}
	headersJSON, _ := json.Marshal(headers)

	bodyData, _ := json.Marshal(map[string]string{
		"chat_id": input.ChatID,
		"text":    input.Text,
	})

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

	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("Telegram API 呼叫失敗")
		return
	}

	responseStr := string(outBuf[:outLen])
	var responseData map[string]interface{}
	if err := json.Unmarshal([]byte(responseStr), &responseData); err != nil {
		responseData = map[string]interface{}{"raw": responseStr}
	}

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

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