fix: dedupe telegram updates and persist update offset

Signed-off-by: Bo <boironic@gmail.com>

main/telegram/telegram_bot.c

@@ -7,6 +7,7 @@
 #include <stdlib.h>
 #include <stdbool.h>
 #include "esp_log.h"
+#include "esp_timer.h"
 #include "esp_http_client.h"
 #include "esp_crt_bundle.h"
 #include "nvs.h"
@@ -16,6 +17,16 @@ static const char *TAG = "telegram";
 
 static char s_bot_token[128] = MIMI_SECRET_TG_TOKEN;
 static int64_t s_update_offset = 0;
+static int64_t s_last_saved_offset = -1;
+static int64_t s_last_offset_save_us = 0;
+
+#define TG_OFFSET_NVS_KEY            "update_offset"
+#define TG_DEDUP_CACHE_SIZE          64
+#define TG_OFFSET_SAVE_INTERVAL_US   (5LL * 1000 * 1000)
+#define TG_OFFSET_SAVE_STEP          10
+
+static uint64_t s_seen_msg_keys[TG_DEDUP_CACHE_SIZE] = {0};
+static size_t s_seen_msg_idx = 0;
 
 /* HTTP response accumulator */
 typedef struct {
@@ -24,6 +35,77 @@ typedef struct {
     size_t cap;
 } http_resp_t;
 
+static uint64_t fnv1a64(const char *s)
+{
+    uint64_t h = 1469598103934665603ULL;
+    if (!s) {
+        return h;
+    }
+    while (*s) {
+        h ^= (unsigned char)(*s++);
+        h *= 1099511628211ULL;
+    }
+    return h;
+}
+
+static uint64_t make_msg_key(const char *chat_id, int msg_id)
+{
+    uint64_t h = fnv1a64(chat_id);
+    return (h << 16) ^ (uint64_t)(msg_id & 0xFFFF) ^ ((uint64_t)msg_id << 32);
+}
+
+static bool seen_msg_contains(uint64_t key)
+{
+    for (size_t i = 0; i < TG_DEDUP_CACHE_SIZE; i++) {
+        if (s_seen_msg_keys[i] == key) {
+            return true;
+        }
+    }
+    return false;
+}
+
+static void seen_msg_insert(uint64_t key)
+{
+    s_seen_msg_keys[s_seen_msg_idx] = key;
+    s_seen_msg_idx = (s_seen_msg_idx + 1) % TG_DEDUP_CACHE_SIZE;
+}
+
+static void save_update_offset_if_needed(bool force)
+{
+    if (s_update_offset <= 0) {
+        return;
+    }
+
+    int64_t now = esp_timer_get_time();
+    bool should_save = force;
+    if (!should_save && s_last_saved_offset >= 0) {
+        if ((s_update_offset - s_last_saved_offset) >= TG_OFFSET_SAVE_STEP) {
+            should_save = true;
+        } else if ((now - s_last_offset_save_us) >= TG_OFFSET_SAVE_INTERVAL_US) {
+            should_save = true;
+        }
+    } else if (!should_save) {
+        should_save = true;
+    }
+
+    if (!should_save) {
+        return;
+    }
+
+    nvs_handle_t nvs;
+    if (nvs_open(MIMI_NVS_TG, NVS_READWRITE, &nvs) != ESP_OK) {
+        return;
+    }
+
+    if (nvs_set_i64(nvs, TG_OFFSET_NVS_KEY, s_update_offset) == ESP_OK) {
+        if (nvs_commit(nvs) == ESP_OK) {
+            s_last_saved_offset = s_update_offset;
+            s_last_offset_save_us = now;
+        }
+    }
+    nvs_close(nvs);
+}
+
 static esp_err_t http_event_handler(esp_http_client_event_t *evt)
 {
     http_resp_t *resp = (http_resp_t *)evt->user_data;
@@ -229,6 +311,7 @@ static void process_updates(const char *json_str)
                 continue;
             }
             s_update_offset = uid + 1;
+            save_update_offset_if_needed(false);
         }
 
         /* Extract message */
@@ -244,6 +327,12 @@ static void process_updates(const char *json_str)
         cJSON *chat_id = cJSON_GetObjectItem(chat, "id");
         if (!chat_id) continue;
 
+        int msg_id_val = -1;
+        cJSON *message_id = cJSON_GetObjectItem(message, "message_id");
+        if (cJSON_IsNumber(message_id)) {
+            msg_id_val = (int)message_id->valuedouble;
+        }
+
         char chat_id_str[32];
         if (cJSON_IsString(chat_id) && chat_id->valuestring) {
             strncpy(chat_id_str, chat_id->valuestring, sizeof(chat_id_str) - 1);
@@ -254,7 +343,18 @@ static void process_updates(const char *json_str)
             continue;
         }
 
-        ESP_LOGI(TAG, "Message from chat %s: %.40s...", chat_id_str, text->valuestring);
+        if (msg_id_val >= 0) {
+            uint64_t msg_key = make_msg_key(chat_id_str, msg_id_val);
+            if (seen_msg_contains(msg_key)) {
+                ESP_LOGW(TAG, "Drop duplicate message update_id=%" PRId64 " chat=%s message_id=%d",
+                         uid, chat_id_str, msg_id_val);
+                continue;
+            }
+            seen_msg_insert(msg_key);
+        }
+
+        ESP_LOGI(TAG, "Message update_id=%" PRId64 " message_id=%d from chat %s: %.40s...",
+                 uid, msg_id_val, chat_id_str, text->valuestring);
 
         /* Push to inbound bus */
         mimi_msg_t msg = {0};
@@ -311,6 +411,13 @@ esp_err_t telegram_bot_init(void)
         if (nvs_get_str(nvs, MIMI_NVS_KEY_TG_TOKEN, tmp, &len) == ESP_OK && tmp[0]) {
             strncpy(s_bot_token, tmp, sizeof(s_bot_token) - 1);
         }
+
+        int64_t offset = 0;
+        if (nvs_get_i64(nvs, TG_OFFSET_NVS_KEY, &offset) == ESP_OK && offset > 0) {
+            s_update_offset = offset;
+            s_last_saved_offset = offset;
+            ESP_LOGI(TAG, "Loaded Telegram update offset: %" PRId64, s_update_offset);
+        }
         nvs_close(nvs);
     }