cc-connect/platform/dingtalk/dingtalk.go

package dingtalk

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"log/slog"
	"mime/multipart"
	"net/http"
	"os/exec"
	"strings"
	"sync"
	"time"

	"github.com/chenhg5/cc-connect/core"

	"github.com/open-dingtalk/dingtalk-stream-sdk-go/chatbot"
	dingtalkClient "github.com/open-dingtalk/dingtalk-stream-sdk-go/client"
	"github.com/open-dingtalk/dingtalk-stream-sdk-go/payload"
	"github.com/open-dingtalk/dingtalk-stream-sdk-go/utils"
)

func init() {
	core.RegisterPlatform("dingtalk", New)
}

type replyContext struct {
	sessionWebhook string
	conversationId string
	senderStaffId  string
	isGroup        bool
	proactive      bool // true when constructed by ReconstructReplyCtx (no sessionWebhook)
}

// richTextContent mirrors the full structure of the DingTalk "text" JSON field,
// which the Go SDK's BotCallbackDataTextModel (Content string) silently drops.
// When a user quotes/replies to a message, DingTalk sends isReplyMsg + repliedMsg.
type richTextContent struct {
	Content    string          `json:"content"`
	IsReplyMsg bool            `json:"isReplyMsg"`
	RepliedMsg *repliedMessage `json:"repliedMsg"`
}

type repliedMessage struct {
	MsgType string          `json:"msgType"`
	Content json.RawMessage `json:"content"`
}

type repliedTextContent struct {
	Text string `json:"text"`
}

const maxQuotedMessageRunes = 4000

type downloadResponse struct {
	DownloadUrl string `json:"downloadUrl"`
}

type Platform struct {
	clientID              string
	clientSecret          string
	robotCode             string
	agentID               int64 // Agent ID for work notifications API (numeric)
	allowFrom             string
	requireMention        bool
	shareSessionInChannel bool
	streamClient          *dingtalkClient.StreamClient
	streamCtxCancel       context.CancelFunc
	handler               core.MessageHandler
	dedup                 core.MessageDedup
	httpClient            *http.Client
	tokenMu               sync.Mutex
	accessToken           string
	tokenExpiry           time.Time
	// AI Card configuration
	cardTemplateID  string
	cardTemplateKey string
	cardThrottleMs  int
	degradeUntil    time.Time
	degradeMu       sync.Mutex
}

func New(opts map[string]any) (core.Platform, error) {
	clientID, _ := opts["client_id"].(string)
	clientSecret, _ := opts["client_secret"].(string)
	robotCode, _ := opts["robot_code"].(string)
	allowFrom, _ := opts["allow_from"].(string)
	core.CheckAllowFrom("dingtalk", allowFrom)
	requireMention, _ := opts["require_mention"].(bool)

	fmt.Println("---- [debug], requireMention= ", requireMention)
	shareSessionInChannel, _ := opts["share_session_in_channel"].(bool)
	if clientID == "" || clientSecret == "" {
		return nil, fmt.Errorf("dingtalk: client_id and client_secret are required")
	}
	if robotCode == "" {
		robotCode = clientID // fallback to client_id if robot_code not specified
	}
	// Validate robot_code format (should not be empty after fallback)
	if robotCode == "" {
		return nil, fmt.Errorf("dingtalk: robot_code is required (or client_id)")
	}

	// agent_id is required for work notifications API (numeric type)
	// Try to read as int64 first, then float64 (JSON numbers), fallback to 0
	var agentID int64
	if v, ok := opts["agent_id"].(int64); ok {
		agentID = v
	} else if v, ok := opts["agent_id"].(float64); ok {
		agentID = int64(v)
	} else if v, ok := opts["agent_id"].(int); ok {
		agentID = int64(v)
	}
	// agent_id can be 0 for testing, but will fail in production

	// AI Card configuration
	cardTemplateID, _ := opts["card_template_id"].(string)
	cardTemplateKey, _ := opts["card_template_key"].(string)
	if cardTemplateKey == "" {
		cardTemplateKey = "content"
	}
	cardThrottleMs := 300
	if v, ok := opts["card_throttle_ms"].(float64); ok && v > 0 {
		cardThrottleMs = int(v)
	} else if v, ok := opts["card_throttle_ms"].(int64); ok && v > 0 {
		cardThrottleMs = int(v)
	} else if v, ok := opts["card_throttle_ms"].(int); ok && v > 0 {
		cardThrottleMs = v
	}

	return &Platform{
		clientID:              clientID,
		clientSecret:          clientSecret,
		robotCode:             robotCode,
		agentID:               agentID,
		allowFrom:             allowFrom,
		requireMention:        requireMention,
		shareSessionInChannel: shareSessionInChannel,
		httpClient:            &http.Client{Timeout: 30 * time.Second},
		cardTemplateID:        cardTemplateID,
		cardTemplateKey:       cardTemplateKey,
		cardThrottleMs:        cardThrottleMs,
	}, nil
}

func (p *Platform) Name() string { return "dingtalk" }

func (p *Platform) Start(handler core.MessageHandler) error {
	p.handler = handler

	p.streamClient = dingtalkClient.NewStreamClient(
		dingtalkClient.WithAppCredential(dingtalkClient.NewAppCredentialConfig(p.clientID, p.clientSecret)),
	)

	// Register a raw frame handler instead of RegisterChatBotCallbackRouter so we
	// can access the original JSON (df.Data). The SDK's BotCallbackDataModel drops
	// fields like text.isReplyMsg and text.repliedMsg during deserialization.
	p.streamClient.RegisterRouter(utils.SubscriptionTypeKCallback, payload.BotMessageCallbackTopic,
		func(ctx context.Context, df *payload.DataFrame) (*payload.DataFrameResponse, error) {
			p.onRawMessage(df.Data)
			return payload.NewSuccessDataFrameResponse(), nil
		})

	ctx, cancel := context.WithCancel(context.Background())
	p.streamCtxCancel = cancel

	// Run the stream in a restart loop. The SDK's processLoop() runs in a background
	// goroutine and handles keepalive pings internally. If the goroutine exits
	// (e.g. server closes idle connection), Start() returns and we attempt to reconnect.
	// This ensures the bot stays connected even after long periods of silence.
	go func() {
		defer slog.Info("dingtalk: stream runner exited")
		for {
			select {
			case <-ctx.Done():
				return
			default:
			}

			if err := p.streamClient.Start(ctx); err != nil {
				slog.Warn("dingtalk: stream disconnected, reconnecting", "error", err)
			}

			// Brief pause before reconnecting to avoid tight loop on persistent failures.
			select {
			case <-ctx.Done():
				return
			case <-time.After(3 * time.Second):
			}
		}
	}()

	slog.Info("dingtalk: stream connected", "client_id", p.clientID)
	return nil
}

// onRawMessage is the entry point for incoming messages. It receives the raw
// JSON from the DingTalk Stream SDK (df.Data) and parses it into the SDK's
// BotCallbackDataModel plus our own richTextContent to recover fields that
// the SDK's typed model silently drops (isReplyMsg, repliedMsg).
func (p *Platform) onRawMessage(rawJSON string) {
	var data chatbot.BotCallbackDataModel
	if err := json.Unmarshal([]byte(rawJSON), &data); err != nil {
		slog.Error("dingtalk: failed to parse callback data", "error", err)
		return
	}

	// Parse the full "text" object from raw JSON to recover isReplyMsg/repliedMsg.
	// The SDK's BotCallbackDataTextModel only has Content string, losing these fields.
	var envelope struct {
		Text richTextContent `json:"text"`
	}
	if err := json.Unmarshal([]byte(rawJSON), &envelope); err != nil {
		slog.Warn("dingtalk: failed to parse rich text content", "error", err)
	}

	p.onMessage(&data, &envelope.Text)
}

func (p *Platform) onMessage(data *chatbot.BotCallbackDataModel, richText *richTextContent) {
	slog.Debug("dingtalk: message received", "user", data.SenderNick, "msgtype", data.Msgtype)

	if p.dedup.IsDuplicate(data.MsgId) {
		slog.Debug("dingtalk: duplicate message ignored", "msg_id", data.MsgId)
		return
	}

	if data.CreateAt > 0 {
		msgTime := time.Unix(data.CreateAt/1000, (data.CreateAt%1000)*int64(time.Millisecond))
		if core.IsOldMessage(msgTime) {
			slog.Debug("dingtalk: ignoring old message after restart", "create_at", data.CreateAt)
			return
		}
	}

	if !core.AllowList(p.allowFrom, data.SenderStaffId) {
		slog.Debug("dingtalk: message from unauthorized user", "user", data.SenderStaffId)
		return
	}

	// In group chats, only respond when the bot is @mentioned (if require_mention is set).
	if p.requireMention && data.ConversationType == "2" && !data.IsInAtList {
		slog.Debug("dingtalk: ignoring group message without @mention", "user", data.SenderNick)
		return
	}

	convType := "d" // direct (1:1)
	if data.ConversationType == "2" {
		convType = "g" // group
	}

	var sessionKey string
	if p.shareSessionInChannel {
		sessionKey = fmt.Sprintf("dingtalk:%s:%s", convType, data.ConversationId)
	} else {
		sessionKey = fmt.Sprintf("dingtalk:%s:%s:%s", convType, data.ConversationId, data.SenderStaffId)
	}

	// Handle audio messages
	if data.Msgtype == "audio" {
		p.handleAudioMessage(data, sessionKey)
		return
	}

	// Handle richText messages — extract plain text and images from rich content
	if data.Msgtype == "richText" {
		text, imageCodes := extractRichText(data.Content)
		if text == "" && len(imageCodes) == 0 {
			slog.Debug("dingtalk: richText message with no extractable content", "msg_id", data.MsgId)
			return
		}

		// Download images from downloadCode
		var images []core.ImageAttachment
		for _, code := range imageCodes {
			imgData, mimeType, err := p.downloadImageByCode(code)
			if err != nil {
				slog.Error("dingtalk: failed to download richText image", "error", err)
				continue
			}
			images = append(images, core.ImageAttachment{
				MimeType: mimeType,
				Data:     imgData,
			})
		}

		msg := &core.Message{
			SessionKey: sessionKey,
			Platform:   "dingtalk",
			UserID:     data.SenderStaffId,
			UserName:   data.SenderNick,
			ChatName:   data.ConversationTitle,
			Content:    text,
			MessageID:  data.MsgId,
			Images:     images,
			ReplyCtx: replyContext{
				sessionWebhook: data.SessionWebhook,
				conversationId: data.ConversationId,
				senderStaffId:  data.SenderStaffId,
			},
		}
		p.handler(p, msg)
		return
	}

	// Handle image messages
	// DingTalk delivers image messages as either "image" or "picture" depending
	// on the client and robot type. Both carry the same downloadCode field.
	if data.Msgtype == "image" || data.Msgtype == "picture" {
		p.handleImageMessage(data, sessionKey)
		return
	}

	// Extract message content, recovering quoted/reply info from richText.
	messageContent := data.Text.Content
	if richText != nil && richText.IsReplyMsg && richText.RepliedMsg != nil {
		slog.Debug("dingtalk: reply message detected", "msgType", richText.RepliedMsg.MsgType)
		messageContent = p.formatReplyContent(richText, messageContent)
	}

	// Handle text messages (default)
	msg := &core.Message{
		SessionKey: sessionKey,
		Platform:   "dingtalk",
		UserID:     data.SenderStaffId,
		UserName:   data.SenderNick,
		ChatName:   data.ConversationTitle,
		Content:    messageContent,
		MessageID:  data.MsgId,
		ChannelKey: data.ConversationId,
		ReplyCtx: replyContext{
			sessionWebhook: data.SessionWebhook,
			conversationId: data.ConversationId,
			senderStaffId:  data.SenderStaffId,
			isGroup:        data.ConversationType == "2",
		},
	}

	p.handler(p, msg)
}

// extractRichText extracts plain text and image download codes from a DingTalk richText content payload.
// The expected structure is: {"richText": [{"text": "..."}, {"downloadCode": "...", "pictureDownloadCode": "...", "type": "picture"}, ...]}
// Returns text and a list of download codes for images found in the rich text.
// Prefers "downloadCode" over "pictureDownloadCode" (the former is used by the messageFiles/download API).
func extractRichText(content interface{}) (string, []string) {
	m, ok := content.(map[string]interface{})
	if !ok {
		return "", nil
	}
	parts, ok := m["richText"].([]interface{})
	if !ok {
		return "", nil
	}
	var b strings.Builder
	var imageCodes []string
	for _, part := range parts {
		item, ok := part.(map[string]interface{})
		if !ok {
			continue
		}
		if text, ok := item["text"].(string); ok {
			b.WriteString(text)
		}
		// Prefer downloadCode (used by handleImageMessage and messageFiles/download API).
		// Fall back to pictureDownloadCode if downloadCode is not present.
		code, _ := item["downloadCode"].(string)
		if code == "" {
			code, _ = item["pictureDownloadCode"].(string)
		}
		if code != "" {
			imageCodes = append(imageCodes, code)
		}
	}
	return strings.TrimSpace(b.String()), imageCodes
}

func (p *Platform) handleAudioMessage(data *chatbot.BotCallbackDataModel, sessionKey string) {
	slog.Debug("dingtalk: audio message received", "user", data.SenderNick)

	// Parse audio content from the raw content
	audioData, ok := data.Content.(map[string]interface{})
	if !ok {
		slog.Error("dingtalk: invalid audio content type", "type", fmt.Sprintf("%T", data.Content))
		return
	}

	downloadCode, _ := audioData["downloadCode"].(string)
	recognition, _ := audioData["recognition"].(string)

	if downloadCode == "" {
		slog.Error("dingtalk: audio message missing downloadCode")
		return
	}

	// Download audio file
	audioBytes, mimeType, err := p.downloadAudio(downloadCode)
	if err != nil {
		slog.Error("dingtalk: failed to download audio", "error", err)
		// Fallback to recognition text if available
		if recognition != "" {
			msg := &core.Message{
				SessionKey: sessionKey,
				Platform:   "dingtalk",
				UserID:     data.SenderStaffId,
				UserName:   data.SenderNick,
				Content:    recognition,
				MessageID:  data.MsgId,
				ChannelKey: data.ConversationId,
				ReplyCtx: replyContext{
					sessionWebhook: data.SessionWebhook,
					conversationId: data.ConversationId,
					senderStaffId:  data.SenderStaffId,
					isGroup:        data.ConversationType == "2",
				},
				FromVoice: true,
			}
			p.handler(p, msg)
		}
		return
	}

	slog.Info("dingtalk: audio downloaded successfully", "size", len(audioBytes), "mime", mimeType)

	// Create message with audio attachment
	msg := &core.Message{
		SessionKey: sessionKey,
		Platform:   "dingtalk",
		UserID:     data.SenderStaffId,
		UserName:   data.SenderNick,
		Content:    recognition, // Use recognition as text content
		MessageID:  data.MsgId,
		ChannelKey: data.ConversationId,
		ReplyCtx: replyContext{
			sessionWebhook: data.SessionWebhook,
			conversationId: data.ConversationId,
			senderStaffId:  data.SenderStaffId,
			isGroup:        data.ConversationType == "2",
		},
		FromVoice: true,
		Audio: &core.AudioAttachment{
			MimeType: mimeType,
			Data:     audioBytes,
			Format:   "amr", // DingTalk typically uses AMR format
		},
	}

	p.handler(p, msg)
}

func (p *Platform) handleImageMessage(data *chatbot.BotCallbackDataModel, sessionKey string) {
	slog.Debug("dingtalk: image message received", "user", data.SenderNick)

	// Parse image content from the raw content
	imageData, ok := data.Content.(map[string]interface{})
	if !ok {
		slog.Error("dingtalk: invalid image content type", "type", fmt.Sprintf("%T", data.Content))
		return
	}

	downloadCode, _ := imageData["downloadCode"].(string)
	if downloadCode == "" {
		slog.Error("dingtalk: image message missing downloadCode")
		return
	}

	// Download image file using the same messageFiles/download API as audio
	downloadURL, err := p.getDownloadURL(downloadCode)
	if err != nil {
		slog.Error("dingtalk: failed to get image download URL", "error", err)
		return
	}

	resp, err := p.httpClient.Get(downloadURL)
	if err != nil {
		slog.Error("dingtalk: failed to download image", "error", err)
		return
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		slog.Error("dingtalk: image download returned status", "status", resp.StatusCode)
		return
	}

	const maxImageBytes = 25 * 1024 * 1024 // 25 MiB, same cap as other platforms
	imgBytes, err := io.ReadAll(io.LimitReader(resp.Body, maxImageBytes+1))
	if err != nil {
		slog.Error("dingtalk: failed to read image data", "error", err)
		return
	}
	if len(imgBytes) > maxImageBytes {
		slog.Error("dingtalk: image too large, dropping", "size", len(imgBytes), "limit", maxImageBytes)
		return
	}

	mimeType := resp.Header.Get("Content-Type")
	if mimeType == "" {
		mimeType = "image/png"
	}

	slog.Info("dingtalk: image downloaded successfully", "size", len(imgBytes), "mime", mimeType)

	msg := &core.Message{
		SessionKey: sessionKey,
		Platform:   "dingtalk",
		UserID:     data.SenderStaffId,
		UserName:   data.SenderNick,
		MessageID:  data.MsgId,
		ReplyCtx: replyContext{
			sessionWebhook: data.SessionWebhook,
			conversationId: data.ConversationId,
			senderStaffId:  data.SenderStaffId,
		},
		Images: []core.ImageAttachment{{
			MimeType: mimeType,
			Data:     imgBytes,
		}},
	}

	p.handler(p, msg)
}

// downloadImageByCode downloads an image using a downloadCode from richText messages.
func (p *Platform) downloadImageByCode(downloadCode string) ([]byte, string, error) {
	downloadURL, err := p.getDownloadURL(downloadCode)
	if err != nil {
		return nil, "", fmt.Errorf("get download URL: %w", err)
	}

	resp, err := p.httpClient.Get(downloadURL)
	if err != nil {
		return nil, "", fmt.Errorf("http get: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return nil, "", fmt.Errorf("download returned status %d", resp.StatusCode)
	}

	const maxImageBytes = 25 * 1024 * 1024
	data, err := io.ReadAll(io.LimitReader(resp.Body, maxImageBytes+1))
	if err != nil {
		return nil, "", fmt.Errorf("read response: %w", err)
	}
	if len(data) > maxImageBytes {
		return nil, "", fmt.Errorf("image too large: %d bytes", len(data))
	}

	mimeType := resp.Header.Get("Content-Type")
	if mimeType == "" {
		mimeType = "image/png"
	}

	return data, mimeType, nil
}

func (p *Platform) downloadAudio(downloadCode string) ([]byte, string, error) {
	// Get download URL
	downloadURL, err := p.getDownloadURL(downloadCode)
	if err != nil {
		return nil, "", fmt.Errorf("get download URL: %w", err)
	}

	// Download audio file
	resp, err := p.httpClient.Get(downloadURL)
	if err != nil {
		return nil, "", fmt.Errorf("http get: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return nil, "", fmt.Errorf("download returned status %d", resp.StatusCode)
	}

	data, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, "", fmt.Errorf("read response: %w", err)
	}

	// Determine MIME type from Content-Type header
	mimeType := resp.Header.Get("Content-Type")
	if mimeType == "" {
		mimeType = "audio/amr" // Default to AMR if not specified
	}

	return data, mimeType, nil
}

func (p *Platform) getDownloadURL(downloadCode string) (string, error) {
	token, err := p.getAccessToken()
	if err != nil {
		return "", fmt.Errorf("get access token: %w", err)
	}

	reqBody := map[string]string{
		"downloadCode": downloadCode,
		"robotCode":    p.robotCode,
	}
	bodyBytes, err := json.Marshal(reqBody)
	if err != nil {
		return "", fmt.Errorf("marshal request: %w", err)
	}

	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()
	req, err := http.NewRequestWithContext(ctx, http.MethodPost,
		"https://api.dingtalk.com/v1.0/robot/messageFiles/download",
		bytes.NewReader(bodyBytes))
	if err != nil {
		return "", fmt.Errorf("create request: %w", err)
	}

	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("x-acs-dingtalk-access-token", token)

	resp, err := p.httpClient.Do(req)
	if err != nil {
		return "", fmt.Errorf("do request: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		respBody, _ := io.ReadAll(resp.Body)
		return "", fmt.Errorf("api returned status %d: %s", resp.StatusCode, string(respBody))
	}

	var result downloadResponse
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return "", fmt.Errorf("decode response: %w", err)
	}

	if result.DownloadUrl == "" {
		return "", fmt.Errorf("empty downloadUrl in response")
	}

	return result.DownloadUrl, nil
}

func (p *Platform) getAccessToken() (string, error) {
	p.tokenMu.Lock()
	defer p.tokenMu.Unlock()

	// Return cached token if still valid
	if p.accessToken != "" && time.Now().Before(p.tokenExpiry) {
		return p.accessToken, nil
	}

	// Request new access token using DingTalk's new API (api.dingtalk.com/v1.0/oauth2/accessToken)
	// This requires POST request with JSON body
	url := "https://api.dingtalk.com/v1.0/oauth2/accessToken"

	reqBody := map[string]string{
		"appKey":    p.clientID,
		"appSecret": p.clientSecret,
	}
	bodyBytes, err := json.Marshal(reqBody)
	if err != nil {
		return "", fmt.Errorf("marshal request: %w", err)
	}

	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(bodyBytes))
	if err != nil {
		return "", fmt.Errorf("create request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")

	resp, err := p.httpClient.Do(req)
	if err != nil {
		return "", fmt.Errorf("do request: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return "", fmt.Errorf("api returned status %d: %s", resp.StatusCode, body)
	}

	var tokenResp struct {
		AccessToken string `json:"accessToken"`
		ExpireIn    int    `json:"expireIn"`
	}
	if err := json.NewDecoder(resp.Body).Decode(&tokenResp); err != nil {
		return "", fmt.Errorf("decode response: %w", err)
	}

	if tokenResp.AccessToken == "" {
		return "", fmt.Errorf("empty accessToken in response")
	}

	// Cache token with 5 minutes buffer before expiry.
	// When the server omits expireIn (or sends 0/negative), fall back to the
	// documented DingTalk default (7200s = 2h) — without this, tokenExpiry
	// would land at time.Now() and every subsequent getAccessToken() would
	// re-fetch a fresh token, hammering the access-token API.
	p.accessToken = tokenResp.AccessToken
	expiry := tokenResp.ExpireIn
	if expiry <= 0 {
		slog.Warn("dingtalk: missing/invalid expireIn in token response, defaulting to 7200s", "got", tokenResp.ExpireIn)
		expiry = 7200
	}
	if expiry > 300 {
		expiry -= 300 // 5 minute buffer
	}
	p.tokenExpiry = time.Now().Add(time.Duration(expiry) * time.Second)

	slog.Debug("dingtalk: access token refreshed", "expires_at", p.tokenExpiry)
	return p.accessToken, nil
}

func (p *Platform) Reply(ctx context.Context, rctx any, content string) error {
	rc, ok := rctx.(replyContext)
	if !ok {
		return fmt.Errorf("dingtalk: invalid reply context type %T", rctx)
	}

	// Fall back to proactive API when sessionWebhook is unavailable
	if rc.proactive || rc.sessionWebhook == "" {
		return p.sendProactiveMessage(ctx, rc, content)
	}

	content = preprocessDingTalkMarkdown(content)

	payload := map[string]any{
		"msgtype":  "markdown",
		"markdown": map[string]string{"title": "reply", "text": content},
	}
	body, err := json.Marshal(payload)
	if err != nil {
		return fmt.Errorf("dingtalk: marshal reply: %w", err)
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, rc.sessionWebhook, bytes.NewReader(body))
	if err != nil {
		return fmt.Errorf("dingtalk: create request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")

	resp, err := core.HTTPClient.Do(req)
	if err != nil {
		return fmt.Errorf("dingtalk: send reply: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("dingtalk: reply returned status %d", resp.StatusCode)
	}
	return nil
}

// Send sends a new message. For proactive contexts (no sessionWebhook),
// it uses the DingTalk group/direct message API instead.
func (p *Platform) Send(ctx context.Context, rctx any, content string) error {
	rc, ok := rctx.(replyContext)
	if !ok {
		return fmt.Errorf("dingtalk: invalid reply context type %T", rctx)
	}
	if rc.proactive || rc.sessionWebhook == "" {
		return p.sendProactiveMessage(ctx, rc, content)
	}
	return p.Reply(ctx, rctx, content)
}

// SendImage uploads and sends an image via DingTalk oToMessages API.
// Implements core.ImageSender.
func (p *Platform) SendImage(ctx context.Context, rctx any, img core.ImageAttachment) error {
	rc, ok := rctx.(replyContext)
	if !ok {
		return fmt.Errorf("dingtalk: SendImage: invalid reply context type %T", rctx)
	}

	name := img.FileName
	if name == "" {
		name = "image.png"
	}

	mediaID, err := p.uploadMedia(ctx, img.Data, name, "image")
	if err != nil {
		return fmt.Errorf("dingtalk: upload image: %w", err)
	}

	slog.Debug("dingtalk: image uploaded", "media_id", mediaID, "size", len(img.Data))

	token, err := p.getAccessToken()
	if err != nil {
		return fmt.Errorf("dingtalk: get access token: %w", err)
	}

	msgParamBytes, _ := json.Marshal(map[string]string{"photoURL": mediaID})
	requestBody := map[string]any{
		"robotCode": p.robotCode,
		"userIds":   []string{rc.senderStaffId},
		"msgKey":    "sampleImageMsg",
		"msgParam":  string(msgParamBytes),
	}

	body, err := json.Marshal(requestBody)
	if err != nil {
		return fmt.Errorf("dingtalk: marshal image message: %w", err)
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodPost,
		"https://api.dingtalk.com/v1.0/robot/oToMessages/batchSend",
		bytes.NewReader(body))
	if err != nil {
		return fmt.Errorf("dingtalk: create image request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("x-acs-dingtalk-access-token", token)

	resp, err := p.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("dingtalk: send image request: %w", err)
	}
	defer resp.Body.Close()

	respBody, _ := io.ReadAll(resp.Body)
	slog.Debug("dingtalk: oToMessages image response", "status", resp.StatusCode, "body", string(respBody))

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("dingtalk: send image failed: status=%d, body=%s", resp.StatusCode, string(respBody))
	}

	slog.Info("dingtalk: image message sent", "media_id", mediaID, "user", rc.senderStaffId)
	return nil
}

var _ core.ImageSender = (*Platform)(nil)
var _ core.StreamingCardPlatform = (*Platform)(nil)
var _ core.ReplyContextReconstructor = (*Platform)(nil)

// CreateStreamingCard creates a new streaming card for the given reply context.
// Implements core.StreamingCardPlatform.
func (p *Platform) CreateStreamingCard(ctx context.Context, replyCtx any) (core.StreamingCard, error) {
	if p.cardTemplateID == "" {
		return nil, fmt.Errorf("dingtalk: card_template_id not configured")
	}
	if p.isCardDegraded() {
		return nil, fmt.Errorf("dingtalk: card API temporarily degraded")
	}
	rc, ok := replyCtx.(replyContext)
	if !ok {
		return nil, fmt.Errorf("dingtalk: invalid reply context type %T", replyCtx)
	}
	return p.createAICard(ctx, rc)
}

// SendFile uploads and sends a file via DingTalk oToMessages API.
// Implements core.FileSender.
func (p *Platform) SendFile(ctx context.Context, rctx any, file core.FileAttachment) error {
	rc, ok := rctx.(replyContext)
	if !ok {
		return fmt.Errorf("dingtalk: SendFile: invalid reply context type %T", rctx)
	}

	name := file.FileName
	if name == "" {
		name = "file"
	}

	mediaID, err := p.uploadMedia(ctx, file.Data, name, "file")
	if err != nil {
		return fmt.Errorf("dingtalk: upload file: %w", err)
	}

	slog.Debug("dingtalk: file uploaded", "media_id", mediaID, "name", name, "size", len(file.Data))

	token, err := p.getAccessToken()
	if err != nil {
		return fmt.Errorf("dingtalk: get access token: %w", err)
	}

	ext := ""
	if idx := strings.LastIndex(name, "."); idx >= 0 {
		ext = name[idx+1:]
	}

	msgParamBytes, _ := json.Marshal(map[string]string{
		"mediaId":  mediaID,
		"fileName": name,
		"fileType": ext,
	})
	requestBody := map[string]any{
		"robotCode": p.robotCode,
		"userIds":   []string{rc.senderStaffId},
		"msgKey":    "sampleFile",
		"msgParam":  string(msgParamBytes),
	}

	body, err := json.Marshal(requestBody)
	if err != nil {
		return fmt.Errorf("dingtalk: marshal file message: %w", err)
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodPost,
		"https://api.dingtalk.com/v1.0/robot/oToMessages/batchSend",
		bytes.NewReader(body))
	if err != nil {
		return fmt.Errorf("dingtalk: create file request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("x-acs-dingtalk-access-token", token)

	resp, err := p.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("dingtalk: send file request: %w", err)
	}
	defer resp.Body.Close()

	respBody, _ := io.ReadAll(resp.Body)
	slog.Debug("dingtalk: oToMessages file response", "status", resp.StatusCode, "body", string(respBody))

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("dingtalk: send file failed: status=%d, body=%s", resp.StatusCode, string(respBody))
	}

	slog.Info("dingtalk: file message sent", "media_id", mediaID, "name", name, "user", rc.senderStaffId)
	return nil
}

var _ core.FileSender = (*Platform)(nil)

// SendAudio uploads audio bytes to DingTalk and sends a voice message.
// Implements core.AudioSender interface.
// Uses DingTalk oToMessages API with msgKey: "sampleAudio" (voice messages).
// DingTalk voice messages only support ogg/amr formats (not mp3).
func (p *Platform) SendAudio(ctx context.Context, rctx any, audio []byte, format string) error {
	rc, ok := rctx.(replyContext)
	if !ok {
		return fmt.Errorf("dingtalk: SendAudio: invalid reply context type %T", rctx)
	}

	slog.Debug("dingtalk: SendAudio called", "format", format, "size", len(audio), "conversation_id", rc.conversationId)

	// Convert MP3 to OGG if needed (DingTalk voice messages only support ogg/amr)
	if strings.ToLower(format) == "mp3" {
		slog.Debug("dingtalk: converting MP3 to OGG format (DingTalk requirement)")
		oggAudio, err := core.ConvertMP3ToOGG(ctx, audio)
		if err != nil {
			slog.Warn("dingtalk: MP3 to OGG conversion failed", "error", err)
			// Fallback: try AMR format instead
			amrAudio, err := core.ConvertMP3ToAMR(ctx, audio)
			if err != nil {
				return fmt.Errorf("dingtalk: convert MP3 to AMR failed: %w", err)
			}
			audio = amrAudio
			format = "amr"
		} else {
			audio = oggAudio
			format = "ogg"
		}
		slog.Debug("dingtalk: audio converted", "new_format", format, "new_size", len(audio))
	}

	// Compress audio if too large (DingTalk limit is 2MB)
	const maxAudioSize = 2 * 1024 * 1024
	if len(audio) > maxAudioSize {
		slog.Debug("dingtalk: audio too large, compressing", "size", len(audio), "max", maxAudioSize)
		compressed, compressedFormat, err := p.compressAudio(ctx, audio, format)
		if err != nil {
			slog.Warn("dingtalk: compression failed, using original", "error", err)
		} else {
			audio = compressed
			format = compressedFormat
			slog.Debug("dingtalk: audio compressed", "new_size", len(audio), "new_format", format)
		}
	}

	// Upload audio to DingTalk media API
	mediaID, err := p.uploadMedia(ctx, audio, fmt.Sprintf("audio.%s", format), "voice")
	if err != nil {
		return fmt.Errorf("dingtalk: upload audio: %w", err)
	}

	slog.Debug("dingtalk: audio uploaded", "media_id", mediaID, "format", format, "size", len(audio))

	// Calculate duration from audio size (rough estimate based on bitrate)
	// NOTE: This is an approximation. For accurate duration, consider using ffprobe or go-audio library.
	// OGG (Opus 64kbps): ~8KB/sec, AMR-NB (12.2kbps): ~4KB/sec, MP3 (128kbps): ~16KB/sec
	var duration int
	if format == "ogg" {
		duration = len(audio) / 8000
	} else if format == "amr" {
		duration = len(audio) / 4000
	} else if format == "mp3" {
		duration = len(audio) / 16000
	} else {
		duration = len(audio) / 32000
	}
	if duration == 0 {
		duration = 1
	}

	durationMs := duration * 1000

	// Use oToMessages API with msgKey: "sampleAudio" for voice messages
	// This is the official API for sending voice messages in bot conversations
	token, err := p.getAccessToken()
	if err != nil {
		return fmt.Errorf("dingtalk: get access token: %w", err)
	}

	// Build oToMessages API request with sampleAudio msgKey
	// msgParam must be a JSON string, not an object
	msgParamJSON := fmt.Sprintf(`{"mediaId":"%s","duration":"%d"}`, mediaID, durationMs)
	requestBody := map[string]interface{}{
		"robotCode": p.robotCode,
		"userIds":   []string{rc.senderStaffId},
		"msgKey":    "sampleAudio",
		"msgParam":  msgParamJSON,
	}

	body, err := json.Marshal(requestBody)
	if err != nil {
		return fmt.Errorf("dingtalk: marshal audio message: %w", err)
	}

	slog.Debug("dingtalk: sending voice via oToMessages API", "media_id", mediaID, "duration", durationMs, "user_id", rc.senderStaffId)

	req, err := http.NewRequestWithContext(ctx, http.MethodPost,
		"https://api.dingtalk.com/v1.0/robot/oToMessages/batchSend",
		bytes.NewReader(body))
	if err != nil {
		return fmt.Errorf("dingtalk: create audio request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("x-acs-dingtalk-access-token", token)

	resp, err := p.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("dingtalk: send audio request: %w", err)
	}
	defer resp.Body.Close()

	respBody, _ := io.ReadAll(resp.Body)
	slog.Debug("dingtalk: oToMessages API response", "status", resp.StatusCode, "body", string(respBody))

	if resp.StatusCode != 200 {
		return fmt.Errorf("dingtalk: send audio failed: status=%d, body=%s", resp.StatusCode, string(respBody))
	}

	slog.Info("dingtalk: voice message sent successfully", "media_id", mediaID, "conversation_id", rc.conversationId)
	return nil
}

// compressAudio compresses audio if it exceeds size limits.
// Uses ffmpeg to convert WAV to MP3 format (DingTalk supported, ~10:1 compression ratio).
func (p *Platform) compressAudio(ctx context.Context, audio []byte, format string) ([]byte, string, error) {
	// Only WAV format can be compressed to MP3
	if strings.ToLower(format) != "wav" {
		return nil, "", fmt.Errorf("only WAV format can be compressed, got: %s", format)
	}

	return p.compressAudioWithFFmpeg(ctx, audio, format)
}

// compressAudioWithFFmpeg compresses audio using ffmpeg with stdin/stdout pipes.
// Converts WAV to MP3 format (64 kbps for voice).
func (p *Platform) compressAudioWithFFmpeg(ctx context.Context, audio []byte, format string) ([]byte, string, error) {
	ffmpegPath, err := exec.LookPath("ffmpeg")
	if err != nil {
		return nil, "", fmt.Errorf("ffmpeg not found: %w", err)
	}

	args := []string{
		"-i", "pipe:0",
		"-ar", "16000", // 16kHz sample rate for voice
		"-ac", "1", // mono
		"-b:a", "64k", // 64 kbps bitrate (voice quality)
		"-f", "mp3",
		"-y",
		"pipe:1",
	}
	cmd := exec.CommandContext(ctx, ffmpegPath, args...)
	cmd.Stdin = bytes.NewReader(audio)
	var stdout, stderr bytes.Buffer
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr

	if err := cmd.Run(); err != nil {
		return nil, "", fmt.Errorf("ffmpeg compression failed: %w (stderr: %s)", err, stderr.String())
	}

	return stdout.Bytes(), "mp3", nil
}

// uploadMedia uploads a file to DingTalk media API and returns the media ID.
// mediaType should be "voice" or "image".
func (p *Platform) uploadMedia(ctx context.Context, data []byte, fileName, mediaType string) (string, error) {
	token, err := p.getAccessToken()
	if err != nil {
		return "", fmt.Errorf("get access token: %w", err)
	}

	uploadURL := fmt.Sprintf("https://oapi.dingtalk.com/media/upload?access_token=%s&type=%s", token, mediaType)

	body := bytes.NewBuffer(nil)
	writer := multipart.NewWriter(body)

	part, err := writer.CreateFormFile("media", fileName)
	if err != nil {
		return "", fmt.Errorf("create form file: %w", err)
	}

	if _, err := part.Write(data); err != nil {
		return "", fmt.Errorf("write media data: %w", err)
	}

	if err := writer.Close(); err != nil {
		return "", fmt.Errorf("close multipart writer: %w", err)
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, uploadURL, body)
	if err != nil {
		return "", fmt.Errorf("create upload request: %w", err)
	}

	req.Header.Set("Content-Type", writer.FormDataContentType())

	resp, err := p.httpClient.Do(req)
	if err != nil {
		return "", fmt.Errorf("upload request: %w", err)
	}
	defer resp.Body.Close()

	respBody, err := io.ReadAll(resp.Body)
	if err != nil {
		return "", fmt.Errorf("read upload response: %w", err)
	}

	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("upload returned status %d: %s", resp.StatusCode, respBody)
	}

	slog.Debug("dingtalk: media upload response", "status", resp.StatusCode, "body", string(respBody))

	var uploadResp struct {
		ErrCode int    `json:"errcode"`
		ErrMsg  string `json:"errmsg"`
		MediaID string `json:"media_id"`
		Type    string `json:"type"`
	}
	if err := json.Unmarshal(respBody, &uploadResp); err != nil {
		return "", fmt.Errorf("decode upload response: %w, body: %s", err, respBody)
	}

	if uploadResp.ErrCode != 0 {
		return "", fmt.Errorf("upload API error %d: %s", uploadResp.ErrCode, uploadResp.ErrMsg)
	}

	if uploadResp.MediaID == "" {
		return "", fmt.Errorf("empty media_id in upload response: %s", respBody)
	}

	slog.Debug("dingtalk: media uploaded successfully", "media_id", uploadResp.MediaID, "type", mediaType, "size", len(data))
	return uploadResp.MediaID, nil
}

func (p *Platform) Stop() error {
	if p.streamCtxCancel != nil {
		p.streamCtxCancel()
	}
	if p.streamClient != nil {
		p.streamClient.Close()
	}
	return nil
}

// formatReplyContent prepends quoted text to the message content when the user
// replies to / quotes a previous message. richText is parsed from the raw JSON
// "text" object which the SDK's BotCallbackDataTextModel silently drops.
func (p *Platform) formatReplyContent(richText *richTextContent, fallback string) string {
	content := richText.Content
	if content == "" {
		content = fallback
	}

	if richText.RepliedMsg == nil {
		return content
	}

	quotedText := p.extractQuotedMessageText(richText.RepliedMsg)
	if quotedText == "" {
		return content
	}

	return fmt.Sprintf("引用: \"%s\"\n\n%s", quotedText, content)
}

func (p *Platform) extractQuotedMessageText(msg *repliedMessage) string {
	if msg == nil {
		return ""
	}

	switch msg.MsgType {
	case "text":
		return p.extractQuotedTextMessageText(msg.Content)
	case "interactiveCard":
		return p.extractInteractiveCardQuotedText(msg.Content)
	default:
		slog.Debug("dingtalk: quoted message type not supported", "type", msg.MsgType)
		return ""
	}
}

func (p *Platform) extractQuotedTextMessageText(raw json.RawMessage) string {
	var repliedContent repliedTextContent
	if err := json.Unmarshal(raw, &repliedContent); err != nil {
		slog.Debug("dingtalk: failed to parse replied message content", "error", err)
		return ""
	}
	return repliedContent.Text
}

func (p *Platform) extractInteractiveCardQuotedText(raw json.RawMessage) string {
	var payload any
	if err := json.Unmarshal(raw, &payload); err != nil {
		slog.Debug("dingtalk: failed to parse quoted interactiveCard content", "error", err)
		return ""
	}
	text := p.extractInteractiveCardTextValue(payload, 0)
	if text == "" {
		slog.Debug("dingtalk: quoted interactiveCard content has no extractable text")
	}
	return normalizeQuotedMessageText(text)
}

func (p *Platform) extractInteractiveCardTextValue(value any, depth int) string {
	if depth > 4 {
		return ""
	}

	switch v := value.(type) {
	case string:
		decoded, ok := decodeJSONObjectOrArray(v)
		if !ok {
			return ""
		}
		return p.extractInteractiveCardTextValue(decoded, depth+1)
	case map[string]any:
		for _, key := range p.interactiveCardTemplateKeys() {
			if text := p.extractInteractiveCardPath(v, depth, "cardData", "cardParamMap", key); text != "" {
				return text
			}
		}
		for _, key := range p.interactiveCardTemplateKeys() {
			if text := p.extractInteractiveCardPath(v, depth, "cardParamMap", key); text != "" {
				return text
			}
		}
		for _, key := range p.interactiveCardTopLevelKeys() {
			if text := p.extractInteractiveCardPath(v, depth, key); text != "" {
				return text
			}
		}
	case []any:
		for _, item := range v {
			if text := p.extractInteractiveCardTextValue(item, depth+1); text != "" {
				return text
			}
		}
	}
	return ""
}

func (p *Platform) extractInteractiveCardPath(root map[string]any, depth int, path ...string) string {
	var current any = root
	for _, part := range path {
		m, ok := mapFromJSONValue(current)
		if !ok {
			return ""
		}
		next, ok := m[part]
		if !ok {
			return ""
		}
		current = next
	}
	return p.extractInteractiveCardLeafText(current, depth+1)
}

func (p *Platform) extractInteractiveCardLeafText(value any, depth int) string {
	if depth > 4 {
		return ""
	}

	switch v := value.(type) {
	case string:
		return strings.TrimSpace(v)
	case map[string]any, []any:
		return p.extractInteractiveCardTextValue(value, depth+1)
	default:
		return ""
	}
}

func (p *Platform) interactiveCardTemplateKeys() []string {
	key := strings.TrimSpace(p.cardTemplateKey)
	if key == "" {
		key = "content"
	}
	if key == "content" {
		return []string{"content"}
	}
	return []string{key, "content"}
}

func (p *Platform) interactiveCardTopLevelKeys() []string {
	return []string{"content", "text", "markdown", "title"}
}

func mapFromJSONValue(value any) (map[string]any, bool) {
	switch v := value.(type) {
	case map[string]any:
		return v, true
	case string:
		decoded, ok := decodeJSONObjectOrArray(v)
		if !ok {
			return nil, false
		}
		m, ok := decoded.(map[string]any)
		return m, ok
	default:
		return nil, false
	}
}

func decodeJSONObjectOrArray(s string) (any, bool) {
	text := strings.TrimSpace(s)
	if text == "" || (!strings.HasPrefix(text, "{") && !strings.HasPrefix(text, "[")) {
		return nil, false
	}
	var decoded any
	if err := json.Unmarshal([]byte(text), &decoded); err != nil {
		return nil, false
	}
	return decoded, true
}

func normalizeQuotedMessageText(s string) string {
	text := strings.TrimSpace(s)
	if text == "" {
		return ""
	}
	runes := []rune(text)
	if len(runes) <= maxQuotedMessageRunes {
		return text
	}
	return string(runes[:maxQuotedMessageRunes]) + "..."
}

// ReconstructReplyCtx implements core.ReplyContextReconstructor.
// Session key format: "dingtalk:{convType}:{conversationId}:{senderStaffId}" or "dingtalk:{convType}:{conversationId}"
// where convType is "g" (group) or "d" (direct/1:1).
func (p *Platform) ReconstructReplyCtx(sessionKey string) (any, error) {
	if !strings.HasPrefix(sessionKey, "dingtalk:") {
		return nil, fmt.Errorf("dingtalk: not a dingtalk session key: %q", sessionKey)
	}

	stripped := strings.TrimPrefix(sessionKey, "dingtalk:")
	parts := strings.SplitN(stripped, ":", 3)

	if len(parts) < 2 {
		return nil, fmt.Errorf("dingtalk: invalid session key format: %q", sessionKey)
	}

	convType := parts[0]
	if convType != "g" && convType != "d" {
		return nil, fmt.Errorf("dingtalk: invalid conversation type %q in session key: %q", convType, sessionKey)
	}

	conversationId := parts[1]
	if conversationId == "" {
		return nil, fmt.Errorf("dingtalk: empty conversationId in session key: %q", sessionKey)
	}

	var senderStaffId string
	if len(parts) > 2 {
		senderStaffId = parts[2]
	}

	return replyContext{
		conversationId: conversationId,
		senderStaffId:  senderStaffId,
		isGroup:        convType == "g",
		proactive:      true,
	}, nil
}

// sendProactiveMessage sends a message using the DingTalk group/direct message API
// instead of the temporary sessionWebhook. This enables cc-connect send, cron,
// webhook, and other proactive messaging features.
func (p *Platform) sendProactiveMessage(ctx context.Context, rc replyContext, content string) error {
	token, err := p.getAccessToken()
	if err != nil {
		return fmt.Errorf("dingtalk: get access token for proactive send: %w", err)
	}

	content = preprocessDingTalkMarkdown(content)

	var apiURL string
	var requestBody map[string]any

	if rc.isGroup && rc.conversationId != "" {
		// Group message via /v1.0/robot/groupMessages/send
		apiURL = "https://api.dingtalk.com/v1.0/robot/groupMessages/send"
		msgParam, _ := json.Marshal(map[string]string{"text": content})
		requestBody = map[string]any{
			"robotCode":          p.robotCode,
			"openConversationId": rc.conversationId,
			"msgKey":             "sampleMarkdown",
			"msgParam":           string(msgParam),
		}
	} else if rc.senderStaffId != "" {
		// Direct message via /v1.0/robot/oToMessages/batchSend
		apiURL = "https://api.dingtalk.com/v1.0/robot/oToMessages/batchSend"
		msgParam, _ := json.Marshal(map[string]string{"title": "reply", "text": content})
		requestBody = map[string]any{
			"robotCode": p.robotCode,
			"userIds":   []string{rc.senderStaffId},
			"msgKey":    "sampleMarkdown",
			"msgParam":  string(msgParam),
		}
	} else {
		return fmt.Errorf("dingtalk: proactive send requires conversationId (group) or senderStaffId (direct)")
	}

	body, err := json.Marshal(requestBody)
	if err != nil {
		return fmt.Errorf("dingtalk: marshal proactive message: %w", err)
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, apiURL, bytes.NewReader(body))
	if err != nil {
		return fmt.Errorf("dingtalk: create proactive request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("x-acs-dingtalk-access-token", token)

	resp, err := p.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("dingtalk: proactive send request: %w", err)
	}
	defer resp.Body.Close()

	respBody, _ := io.ReadAll(resp.Body)
	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("dingtalk: proactive send failed: status=%d, body=%s", resp.StatusCode, string(respBody))
	}

	slog.Debug("dingtalk: proactive message sent", "api", apiURL, "status", resp.StatusCode)
	return nil
}

// preprocessDingTalkMarkdown adapts content for DingTalk's markdown renderer:
//   - Leading spaces → non-breaking spaces (prevents markdown from stripping indentation)
//   - Single \n between non-empty lines → trailing two-space forced line break
//   - Code blocks are left untouched
func preprocessDingTalkMarkdown(s string) string {
	lines := strings.Split(s, "\n")
	inCodeBlock := false

	for i, line := range lines {
		trimmed := strings.TrimSpace(line)
		if strings.HasPrefix(trimmed, "```") {
			inCodeBlock = !inCodeBlock
		}
		if inCodeBlock {
			continue
		}
		spaceCount := len(line) - len(strings.TrimLeft(line, " "))
		if spaceCount > 0 {
			lines[i] = strings.Repeat("\u00A0", spaceCount) + line[spaceCount:]
		}
	}

	var sb strings.Builder
	for i, line := range lines {
		sb.WriteString(line)
		if i < len(lines)-1 {
			if line != "" && lines[i+1] != "" {
				sb.WriteString("  \n")
			} else {
				sb.WriteString("\n")
			}
		}
	}
	return sb.String()
}