Phase 1 MVP — echo bot factory

telegram.go

@@ -0,0 +1,166 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"time"
+)
+
+const telegramAPIBase = "https://api.telegram.org"
+
+type TelegramClient struct {
+	httpClient *http.Client
+	apiBase    string
+}
+
+func NewTelegramClient() *TelegramClient {
+	return &TelegramClient{
+		httpClient: &http.Client{Timeout: 10 * time.Second},
+		apiBase:    telegramAPIBase,
+	}
+}
+
+type SendMessageParams struct {
+	ChatID int64  `json:"chat_id"`
+	Text   string `json:"text"`
+}
+
+type apiResponse struct {
+	OK          bool            `json:"ok"`
+	Description string          `json:"description,omitempty"`
+	Result      json.RawMessage `json:"result,omitempty"`
+	ErrorCode   int             `json:"error_code,omitempty"`
+}
+
+func (c *TelegramClient) SendMessage(ctx context.Context, token string, params SendMessageParams) error {
+	body, err := json.Marshal(params)
+	if err != nil {
+		return err
+	}
+	endpoint := fmt.Sprintf("%s/bot%s/sendMessage", c.apiBase, token)
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint, bytes.NewReader(body))
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	respBody, _ := io.ReadAll(resp.Body)
+
+	var ar apiResponse
+	if jerr := json.Unmarshal(respBody, &ar); jerr != nil {
+		return fmt.Errorf("decode telegram response (status %d): %w", resp.StatusCode, jerr)
+	}
+	if !ar.OK {
+		return fmt.Errorf("telegram api error (code=%d): %s", ar.ErrorCode, ar.Description)
+	}
+	return nil
+}
+
+type SetWebhookParams struct {
+	URL                string   `json:"url"`
+	SecretToken        string   `json:"secret_token,omitempty"`
+	DropPendingUpdates bool     `json:"drop_pending_updates,omitempty"`
+	AllowedUpdates     []string `json:"allowed_updates,omitempty"`
+	MaxConnections     int      `json:"max_connections,omitempty"`
+}
+
+func (c *TelegramClient) SetWebhook(ctx context.Context, token string, params SetWebhookParams) error {
+	body, err := json.Marshal(params)
+	if err != nil {
+		return err
+	}
+	endpoint := fmt.Sprintf("%s/bot%s/setWebhook", c.apiBase, token)
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint, bytes.NewReader(body))
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	respBody, _ := io.ReadAll(resp.Body)
+
+	var ar apiResponse
+	if jerr := json.Unmarshal(respBody, &ar); jerr != nil {
+		return fmt.Errorf("decode telegram response (status %d): %w", resp.StatusCode, jerr)
+	}
+	if !ar.OK {
+		return fmt.Errorf("telegram setWebhook error (code=%d): %s", ar.ErrorCode, ar.Description)
+	}
+	return nil
+}
+
+func (c *TelegramClient) DeleteWebhook(ctx context.Context, token string) error {
+	endpoint := fmt.Sprintf("%s/bot%s/deleteWebhook", c.apiBase, token)
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint, nil)
+	if err != nil {
+		return err
+	}
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	respBody, _ := io.ReadAll(resp.Body)
+
+	var ar apiResponse
+	if jerr := json.Unmarshal(respBody, &ar); jerr != nil {
+		return fmt.Errorf("decode telegram response (status %d): %w", resp.StatusCode, jerr)
+	}
+	if !ar.OK {
+		return fmt.Errorf("telegram deleteWebhook error (code=%d): %s", ar.ErrorCode, ar.Description)
+	}
+	return nil
+}
+
+type WebhookInfo struct {
+	URL                string `json:"url"`
+	HasCustomCert      bool   `json:"has_custom_certificate"`
+	PendingUpdateCount int    `json:"pending_update_count"`
+	LastErrorDate      int64  `json:"last_error_date,omitempty"`
+	LastErrorMessage   string `json:"last_error_message,omitempty"`
+}
+
+func (c *TelegramClient) GetWebhookInfo(ctx context.Context, token string) (*WebhookInfo, error) {
+	endpoint := fmt.Sprintf("%s/bot%s/getWebhookInfo", c.apiBase, token)
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, endpoint, nil)
+	if err != nil {
+		return nil, err
+	}
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	respBody, _ := io.ReadAll(resp.Body)
+
+	var ar apiResponse
+	if jerr := json.Unmarshal(respBody, &ar); jerr != nil {
+		return nil, fmt.Errorf("decode telegram response: %w", jerr)
+	}
+	if !ar.OK {
+		return nil, fmt.Errorf("telegram getWebhookInfo error: %s", ar.Description)
+	}
+	var info WebhookInfo
+	if jerr := json.Unmarshal(ar.Result, &info); jerr != nil {
+		return nil, fmt.Errorf("decode webhook info: %w", jerr)
+	}
+	return &info, nil
+}
+
+// botBuildURL is exposed for tests; not used directly.
+var _ = url.Parse