Fix replaymode = "lastspoke" by using line numbers rather than time to calculate replay start point.

Introduce new function doreplaylastspoke() to achieve this, move doreplay() into replay.c as doreplaytime() and refactor common things into sanitisereplay().

6 files changed, 246 insertions, 150 deletions

diff --git a/TODO b/TODO
index a5f65f0..e10a4e9 100644
--- a/TODO
+++ b/TODO
@@ -10,6 +10,7 @@ macOS compiler may need limits.h included in structures.h.
 
 Sometimes replaymode = "lastspoke" will replay the last message you sent if you spoke last and sometimes it doesn't - change to always include your last message?
 Time based issue due to "seconds ago" rather than specific timestamp?  Perhaps extract timestamp and replay from there.
+(Pending real world testing to be marked as fixed.)
 
 Can memory usage be reduced further?  (e.g. better channel struct management)
 
@@ -40,4 +41,6 @@ Git version in code.
 
 Sending ^D when running with ./blabouncer -f does crazy stuff.
 
+Connecting from irssi triggers doautoreplay() from "USER received" in message.c twice.
+
 Crash when requesting 30 hour replay.
diff --git a/functions.c b/functions.c
index 917f688..6d85d8e 100644
--- a/functions.c
+++ b/functions.c
@@ -873,110 +873,6 @@ int channelindex(struct channel *channels, int maxchannelcount, char *name) {
   return -1;
 }
 
-// Send the requested number of seconds worth of replay log lines to the requested client.
-// 'sourcefd' is the client to send to, and 'replayseconds' is the number of
-// seconds of replay log to replay.
-// Returns 1 for success or 0 for failure.
-int doreplay(int sourcefd, int replayseconds, struct client *clients, struct settings *settings, struct ircdstate *ircdstate, struct channel *channels) {
-  char outgoingmsg[MAXDATASIZE];
-
-  // Figure out how many lines to replay
-  int numlines = replaylines(replayseconds, settings->basedir);
-  debugprint(DEBUG_FULL, "Replay log lines: '%d'.\n", numlines);
-
-  if (numlines < 0) {
-    debugprint(DEBUG_CRIT, "Error getting number of replay lines.\n");
-    return 0;
-  } else if (numlines == 0) {
-    snprintf(outgoingmsg, MAXDATASIZE, "NOTICE %s :0 replay log lines found in the time requested, nothing to send.", ircdstate->ircnick);
-    sendtoclient(sourcefd, outgoingmsg, clients, settings, 0);
-    return 1;
-  }
-
-  // Announce the start
-  snprintf(outgoingmsg, MAXDATASIZE, "NOTICE %s :Starting log replay....", ircdstate->ircnick);
-  sendtoclient(sourcefd, outgoingmsg, clients, settings, 0);
-
-  // Replay those lines!
-  for (int i = 0; i < numlines; i++) {
-    int ret = readreplayline(replayseconds, i, outgoingmsg, settings, ircdstate);
-    if (ret == 0) {
-      debugprint(DEBUG_CRIT, "Error requesting replay line.\n");
-      return 0;
-    } else if (ret == -1) {
-      debugprint(DEBUG_FULL, "doreplay(): readreplayline() said to ignore replay line.\n");
-      continue;
-    }
-
-    // Check if the replay line is a TOPIC, a JOIN, or a PART so we don't
-    // replay those if we are not currently in the channel they are from
-    // otherwise clients and state go a bit mad.
-    // Never replay them if they are from us.
-
-    // Copy to a temporary string
-    char *strcopy = strdup(outgoingmsg);
-    // Keep track of initial pointer for free()ing later
-    char *strcopyPtr = strcopy;
-
-    // Build array of each space-separated token
-    char tokens[3][MAXDATASIZE];
-    char *token;
-
-    for (int j = 0; j < 3; j++) {
-      // Try to split
-      if ((token = strsep(&strcopy, " ")) == NULL) {
-        debugprint(DEBUG_CRIT, "doreplay(): error splitting string on iteration '%d', returning!\n", j);
-        return 0;
-      }
-      // Copy into the token array (strlen + 1 to get the NULL terminator)
-      strncpy(tokens[j], token, strlen(token) + 1);
-    }
-
-    if (strncmp(tokens[1], "TOPIC", strlen("TOPIC")) == 0 ||
-        strncmp(tokens[1], "JOIN", strlen("JOIN")) == 0 ||
-        strncmp(tokens[1], "PART", strlen("PART")) == 0) {
-      // Skip over colon if present in channel name
-      int offset = 0;
-      if (tokens[2][0] == ':') {
-        offset = 1;
-      }
-
-      // To make sure it's not us
-      extractnickfromprefix(tokens[0], 1);
-
-      // Check if we're currently in this channel or if the log line is from us
-      if (!inchannel(channels, ircdstate->maxchannelcount, tokens[2] + offset) ||
-          ((strlen(tokens[0]) == strlen(ircdstate->ircnick)) && (strncmp(tokens[0], ircdstate->ircnick, strlen(tokens[0])) == 0))) {
-        debugprint(DEBUG_FULL, "Not sending '%s' replay line '%s'.\n", tokens[1], outgoingmsg);
-        free(strcopyPtr);
-        continue;
-      }
-    }
-
-    // Separate special check for if a NICK change is from us but it isn't our current nick
-    if (strncmp(tokens[1], "NICK", strlen("NICK")) == 0) {
-      extractnickfromprefix(tokens[0], 1);
-
-      if ((strlen(tokens[0]) == strlen(ircdstate->ircnick)) && (strncmp(tokens[0], ircdstate->ircnick, strlen(tokens[0])) == 0)) {
-        debugprint(DEBUG_FULL, "Not sending '%s' replay line '%s'.\n", tokens[1], outgoingmsg);
-        free(strcopyPtr);
-        continue;
-      }
-    }
-
-    free(strcopyPtr);
-
-    debugprint(DEBUG_FULL, "Sending replay line: '%s'.\n", outgoingmsg);
-    sendtoclient(sourcefd, outgoingmsg, clients, settings, 0);
-  }
-
-  // Announce the end
-  snprintf(outgoingmsg, MAXDATASIZE, "NOTICE %s :Log replay complete.", ircdstate->ircnick);
-  sendtoclient(sourcefd, outgoingmsg, clients, settings, 0);
-
-  return 1;
-}
-
 // Send the auto replay to the requested client, where 'sourcefd' is the client
 // to send to.  The type of replay will depend on the user's settings.
 // Returns 1 for success or 0 for failure.
@@ -989,9 +885,9 @@ int doautoreplay(int sourcefd, struct client *clients, struct settings *settings
 
   // If replaymode = "time" then send whatever replayseconds is set to
   if (!strncmp(settings->replaymode, "time", strlen("time"))) {
-    debugprint(DEBUG_FULL, "doautoreplay(): replaymode = \"time\", calling doreplay() with '%d' seconds.\n", settings->replayseconds);
-    if (!doreplay(sourcefd, settings->replayseconds, clients, settings, ircdstate, channels)) {
-      debugprint(DEBUG_SOME, "doautoreplay(): doreplay() returned 0, returning 0 to caller...\n");
+    debugprint(DEBUG_FULL, "doautoreplay(): replaymode = \"time\", calling doreplaytime() with '%d' seconds.\n", settings->replayseconds);
+    if (!doreplaytime(sourcefd, settings->replayseconds, clients, settings, ircdstate, channels)) {
+      debugprint(DEBUG_SOME, "doautoreplay(): doreplaytime() returned 0, returning 0 to caller...\n");
       return 0;
     }
     return 1;
@@ -999,15 +895,15 @@ int doautoreplay(int sourcefd, struct client *clients, struct settings *settings
 
   // If replaymode = "lastspoke" then send whatever happened since the user's current nick last spoke
   if (!strncmp(settings->replaymode, "lastspoke", strlen("lastspoke"))) {
-    debugprint(DEBUG_FULL, "doautoreplay(): replaymode = \"lastspoke\".\n", settings->replayseconds);
-    int secondsago = lastspokesecondsago(ircdstate->ircnick, settings->basedir);
-    if (secondsago < 1) {
-      debugprint(DEBUG_SOME, "doautoreplay(): lastspokesecondsago() returned < 1, returning 0 to caller...\n");
+    debugprint(DEBUG_FULL, "doautoreplay(): replaymode = \"lastspoke\", calling doreplaylastspoke().\n");
+    long linenumber = lastspokelinenumber(ircdstate->ircnick, settings->basedir);
+    if (linenumber < 1) {
+      debugprint(DEBUG_SOME, "doautoreplay(): lastspokelinenumber() returned < 1, returning 0 to caller...\n");
       return 0;
     }
-    debugprint(DEBUG_FULL, "doautoreplay(): replaymode = \"lastspoke\", sending lines from '%d' seconds ago to sourcefd '%d'.\n", secondsago, sourcefd);
-    if (!doreplay(sourcefd, secondsago, clients, settings, ircdstate, channels)) {
-      debugprint(DEBUG_SOME, "doautoreplay(): doreplay() returned 0, returning 0 to caller...\n");
+    debugprint(DEBUG_FULL, "doautoreplay(): replaymode = \"lastspoke\", replaying from line '%ld' to sourcefd '%d'.\n", linenumber, sourcefd);
+    if (!doreplaylastspoke(sourcefd, linenumber, clients, settings, ircdstate, channels)) {
+      debugprint(DEBUG_SOME, "doautoreplay(): doreplaylastspoke() returned 0, returning 0 to caller...\n"); // CORRECT?
       return 0;
     }
     return 1;
@@ -1016,8 +912,8 @@ int doautoreplay(int sourcefd, struct client *clients, struct settings *settings
   // If replaymode = "noclients" and there is currently only one client connected, then send whatever happened since there were last no clients connected
   if (!strncmp(settings->replaymode, "noclients", strlen("noclients")) && numclients(clients) == 1) {
     debugprint(DEBUG_FULL, "doautoreplay(): replaymode = \"noclients\", sending '%d' seconds of replay.\n", time(NULL) - ircdstate->clientsnonetime);
-    if (!doreplay(sourcefd, time(NULL) - ircdstate->clientsnonetime, clients, settings, ircdstate, channels)) {
-      debugprint(DEBUG_SOME, "doautoreplay(): doreplay() returned 0, returning 0 to caller...\n");
+    if (!doreplaytime(sourcefd, time(NULL) - ircdstate->clientsnonetime, clients, settings, ircdstate, channels)) {
+      debugprint(DEBUG_SOME, "doautoreplay(): doreplaytime() returned 0, returning 0 to caller...\n");
       return 0;
     }
     return 1;
@@ -1026,8 +922,8 @@ int doautoreplay(int sourcefd, struct client *clients, struct settings *settings
   // If replaymode = "lastchange" then send whatever happened since the last client registration or disconnection
   if (!strncmp(settings->replaymode, "lastchange", strlen("lastchange"))) {
     debugprint(DEBUG_FULL, "doautoreplay(): replaymode = \"lastchange\", sending '%d' seconds of replay.\n", time(NULL) - ircdstate->clientchangetime);
-    if (!doreplay(sourcefd, time(NULL) - ircdstate->clientchangetime, clients, settings, ircdstate, channels)) {
-      debugprint(DEBUG_SOME, "doautoreplay(): doreplay() returned 0, returning 0 to caller...\n");
+    if (!doreplaytime(sourcefd, time(NULL) - ircdstate->clientchangetime, clients, settings, ircdstate, channels)) {
+      debugprint(DEBUG_SOME, "doautoreplay(): doreplaytime() returned 0, returning 0 to caller...\n");
       return 0;
     }
     return 1;
diff --git a/functions.h b/functions.h
index c22d7ac..28b6413 100644
--- a/functions.h
+++ b/functions.h
@@ -142,12 +142,6 @@ int inchannel(struct channel *channels, int maxchannelcount, char *name);
 // Returns -1 if there was an error.
 int channelindex(struct channel *channels, int maxchannelcount, char *name);
 
-// Send the requested number of lines of replay log to the requested client.
-// 'sourcefd' is the client to send to, and replayseconds is the number of
-// seconds of replay log to replay.
-// Returns 1 for success or 0 for failure.
-int doreplay(int sourcefd, int replayseconds, struct client *clients, struct settings *settings, struct ircdstate *ircdstate, struct channel *channels);
-
 // Send the auto replay to the requested client, where 'sourcefd' is the client
 // to send to.  The type of replay will depend on the user's settings.
 // Returns 1 for success or 0 for failure.
diff --git a/message.c b/message.c
index 9c07a83..c205709 100644
--- a/message.c
+++ b/message.c
@@ -1370,7 +1370,7 @@ int processclientmessage(SSL *server_ssl, char *str, struct client *clients, int
 
       debugprint(DEBUG_FULL, "Replaying '%s' which is '%d' seconds.\n", tokens[2], replayseconds);
 
-      if (!doreplay(sourcefd, replayseconds, clients, settings, ircdstate, channels)) {
+      if (!doreplaytime(sourcefd, replayseconds, clients, settings, ircdstate, channels)) {
         snprintf(outgoingmsg, MAXDATASIZE, "NOTICE %s :Unable to read replay log file!", ircdstate->ircnick);
         sendtoclient(sourcefd, outgoingmsg, clients, settings, 0);
       }
@@ -1448,7 +1448,7 @@ int processclientmessage(SSL *server_ssl, char *str, struct client *clients, int
           sendtoclient(sourcefd, outgoingmsg, clients, settings, 0);
           return 1;
         }
-        if (!doreplay(sourcefd, time(NULL) - codetime, clients, settings, ircdstate, channels)) {
+        if (!doreplaytime(sourcefd, time(NULL) - codetime, clients, settings, ircdstate, channels)) {
           snprintf(outgoingmsg, MAXDATASIZE, "NOTICE %s :Unable to read replay log file!", ircdstate->ircnick);
           sendtoclient(sourcefd, outgoingmsg, clients, settings, 0);
           return 1;
diff --git a/replay.c b/replay.c
index 5dcf5e6..c63e859 100644
--- a/replay.c
+++ b/replay.c
@@ -175,9 +175,78 @@ void formattime(char *str, int replaydates) {
   str[len + strlen(timestampf)] = '\0';
 }
 
+// Sanitise a potential replay string 'str' by detecting if replay line is any of:
+// 1. TOPIC/JOIN/PART but we're not in the channel any more
+// 2. TOPIC/JOIN/PART and it was from us
+// 3. NICK from us but not our current nick
+// Returns 1 if the replay line should go through as is
+// Returns 0 if the replay line should be skipped
+// Returns -1 on error
+int sanitisereplay (char *str, struct ircdstate *ircdstate, struct channel *channels) {
+  // Check if the replay line is a TOPIC, a JOIN, or a PART so we don't
+  // replay those if we are not currently in the channel they are from
+  // otherwise clients and state go a bit mad.
+  // Never replay them if they are from us.
+
+  // Copy to a temporary string
+  char *strcopy = strdup(str);
+  // Keep track of initial pointer for free()ing later
+  char *strcopyPtr = strcopy;
+
+  // Build array of each space-separated token
+  char tokens[3][MAXDATASIZE];
+  char *token;
+
+  for (int i = 0; i < 3; i++) {
+    // Try to split
+    if ((token = strsep(&strcopy, " ")) == NULL) {
+      debugprint(DEBUG_CRIT, "sanitisereplay(): error splitting string on iteration '%d', returning!\n", i);
+      free(strcopyPtr);
+      return -1;
+    }
+    // Copy into the token array (strlen + 1 to get the NULL terminator)
+    strncpy(tokens[i], token, strlen(token) + 1);
+  }
+
+  if (strncmp(tokens[1], "TOPIC", strlen("TOPIC")) == 0 ||
+      strncmp(tokens[1], "JOIN", strlen("JOIN")) == 0 ||
+      strncmp(tokens[1], "PART", strlen("PART")) == 0) {
+    // Skip over colon if present in channel name
+    int offset = 0;
+    if (tokens[2][0] == ':') {
+      offset = 1;
+    }
+
+    // To make sure it's not us
+    extractnickfromprefix(tokens[0], 1);
+
+    // Check if we're currently in this channel or if the log line is from us
+    if (!inchannel(channels, ircdstate->maxchannelcount, tokens[2] + offset) ||
+        ((strlen(tokens[0]) == strlen(ircdstate->ircnick)) && (strncmp(tokens[0], ircdstate->ircnick, strlen(tokens[0])) == 0))) {
+      debugprint(DEBUG_FULL, "sanitisereplay(): Not sending '%s' replay line '%s'.\n", tokens[1], str);
+      free(strcopyPtr);
+      return 0;
+    }
+  }
+
+  // Separate special check for if a NICK change is from us but it isn't our current nick
+  if (strncmp(tokens[1], "NICK", strlen("NICK")) == 0) {
+    extractnickfromprefix(tokens[0], 1);
+
+    if ((strlen(tokens[0]) == strlen(ircdstate->ircnick)) && (strncmp(tokens[0], ircdstate->ircnick, strlen(tokens[0])) == 0)) {
+      debugprint(DEBUG_FULL, "sanitisereplay(): Not sending '%s' replay line '%s'.\n", tokens[1], str);
+      free(strcopyPtr);
+      return 0;
+    }
+  }
+
+  free(strcopyPtr);
+  return 1;
+}
+
 // Return the number of lines in the replay log since 'seconds' seconds ago, or -1 if there a problem.
 // 'basedir' is the directory in which to find 'replay.log'.
-int replaylines(int seconds, char *basedir) {
+int replaylinestime(int seconds, char *basedir) {
   FILE *fp;
   char str[MAXCHAR];
   char filename[PATH_MAX];
@@ -287,35 +356,37 @@ int readreplayline(int seconds, int linenum, char *str, struct settings *setting
   return 0;
 }
 
-// Returns the number of seconds ago that 'nick' last spoke, or -1 if there is a problem.
+// Returns the line number in the replay log file on which 'nick' last spoke, or -1 if there is a problem.
 // 'basedir' is the directory in which to find 'replay.log'.
-int lastspokesecondsago(char *nick, char *basedir) {
+long lastspokelinenumber(char *nick, char *basedir) {
   FILE *fp;
-  char str[MAXCHAR];
+  char line[MAXCHAR];
   char filename[PATH_MAX];
 
   // Build path
-  snprintf(filename, PATH_MAX, "%s/replay.log", basedir);
-
-  int lastspoketime = 0; // When 'nick' last spoke
+  if (!snprintf(filename, PATH_MAX, "%s/replay.log", basedir)) {
+    debugprint(DEBUG_CRIT, "lastspokelinenumber(): error: couldn't prepare replay path, exiting!\n");
+    exit(1);
+  }
 
-  // Get the current time for comparison later
-  int timenow = (int)time(NULL);
+  long linenumber = -1; // Line number where 'nick' last spoke
 
   fp = fopen(filename, "r");
 
   if (fp == NULL) {
-    debugprint(DEBUG_FULL, "error: replaylineslastspoke(): could not open replay log '%s'.\n", filename);
+    debugprint(DEBUG_FULL, "error: lastspokelinenumber(): could not open replay log '%s'.\n", filename);
     // Assume the file just doesn't exist yet - TODO - Interpret error codes to see what happened.
-    return 0;
+    return -1;
   }
 
-  while (fgets(str, MAXCHAR, fp) != NULL) {
+  long curlinenumber = -1; // Current line number of this file reading loop
+  while (fgets(line, MAXCHAR, fp) != NULL) {
+    curlinenumber++;
     // Split the line up to determine if it was a PRIVMSG sent by the requested 'nick'
     // TODO - This may also be terribly inefficient
 
     // Copy to a temporary string
-    char *strcopy = strdup(str);
+    char *strcopy = strdup(line);
     // Keep track of initial pointer for free()ing later
     char *strcopyPtr = strcopy;
 
@@ -326,7 +397,7 @@ int lastspokesecondsago(char *nick, char *basedir) {
     for (int i = 0; i < 3; i++) {
       // Try to split
       if ((token = strsep(&strcopy, " ")) == NULL) {
-        debugprint(DEBUG_CRIT, "replaylineslastspoke(): error splitting string on iteration '%d', returning -1!\n", i);
+        debugprint(DEBUG_CRIT, "lastspokelinenumber(): error splitting string on iteration '%d', returning -1!\n", i);
         return -1;
       }
       // Copy into the token array (strlen + 1 to get the NULL terminator)
@@ -337,14 +408,14 @@ int lastspokesecondsago(char *nick, char *basedir) {
 
     // Make sure there were at least three tokens
     if (counter < 3) {
-      debugprint(DEBUG_CRIT, "replaylineslastspoke(): not enough tokens on line, only '%d', returning -1!\n", counter);
+      debugprint(DEBUG_CRIT, "lastspokelinenumber(): not enough tokens on line, only '%d', returning -1!\n", counter);
       return -1;
     }
 
     // Make sure it started with a valid timestamp
     int timestamp = gettimestamp(tokens[0]);
     if (timestamp < 0) {
-      debugprint(DEBUG_CRIT, "replaylineslastspoke(): line didn't start with a timestamp, returning -1!\n", counter);
+      debugprint(DEBUG_CRIT, "lastspokelinenumber(): line didn't start with a timestamp, returning -1!\n", counter);
     }
 
     // Is it a PRIVMSG?
@@ -356,16 +427,136 @@ int lastspokesecondsago(char *nick, char *basedir) {
     // Was it said by our 'nick'?  Disable extractnickfromprefix() debugging
     // as it gets very noisy when we call it from here.
     extractnickfromprefix(tokens[1], 0);
-    if ((strlen(tokens[1]) == strlen(nick)) && (strncmp(tokens[1], nick, strlen(nick)))) {
-      // Not our 'nick', continue
+    if ((strlen(tokens[1]) == strlen(nick)) && (strncmp(tokens[1], nick, strlen(nick)) == 0)) {
+      // Our 'nick' found, set the line number
+      linenumber = curlinenumber;
+    }
+  }
+
+  debugprint(DEBUG_FULL, "lastspokelinenumber(): last spoke on line '%ld'.\n", linenumber);
+
+  fclose(fp);
+  return linenumber;
+}
+
+// Send the requested number of seconds worth of replay log lines to the requested client.
+// 'sourcefd' is the client to send to, and 'replayseconds' is the number of
+// seconds of replay log to replay.
+// Returns 1 for success or 0 for failure.
+int doreplaytime(int sourcefd, int replayseconds, struct client *clients, struct settings *settings, struct ircdstate *ircdstate, struct channel *channels) {
+  char outgoingmsg[MAXDATASIZE];
+
+  // Figure out how many lines to replay
+  int numlines = replaylinestime(replayseconds, settings->basedir);
+  debugprint(DEBUG_FULL, "doreplaytime(): Replay log lines: '%d'.\n", numlines);
+
+  if (numlines < 0) {
+    debugprint(DEBUG_CRIT, "doreplaytime(): Error getting number of replay lines.\n");
+    return 0;
+  } else if (numlines == 0) {
+    snprintf(outgoingmsg, MAXDATASIZE, "NOTICE %s :0 replay log lines found in the time requested, nothing to send.", ircdstate->ircnick);
+    sendtoclient(sourcefd, outgoingmsg, clients, settings, 0);
+    return 1;
+  }
+
+  // Announce the start
+  snprintf(outgoingmsg, MAXDATASIZE, "NOTICE %s :Starting log replay....", ircdstate->ircnick);
+  sendtoclient(sourcefd, outgoingmsg, clients, settings, 0);
+
+  // Replay those lines!
+  for (int i = 0; i < numlines; i++) {
+    int ret = readreplayline(replayseconds, i, outgoingmsg, settings, ircdstate);
+    if (ret == 0) {
+      debugprint(DEBUG_CRIT, "doreplaytime(): Error requesting replay line.\n");
+      return 0;
+    } else if (ret == -1) {
+      debugprint(DEBUG_FULL, "doreplaytime(): readreplayline() said to ignore replay line.\n");
       continue;
     }
 
-    lastspoketime = timestamp;
+    if (sanitisereplay(outgoingmsg, ircdstate, channels) < 1) {
+      continue;
+    }
+
+    debugprint(DEBUG_FULL, "doreplaytime(): Sending replay line: '%s'.\n", outgoingmsg);
+    sendtoclient(sourcefd, outgoingmsg, clients, settings, 0);
   }
 
-  fclose(fp);
-  return timenow - lastspoketime;
+  // Announce the end
+  snprintf(outgoingmsg, MAXDATASIZE, "NOTICE %s :Log replay complete.", ircdstate->ircnick);
+  sendtoclient(sourcefd, outgoingmsg, clients, settings, 0);
+
+  return 1;
+}
+
+// Send replay log lines from line number 'linenumber' onwards, to client 'sourcefd'.
+// Returns 1 for success or 0 for failure.
+int doreplaylastspoke(int sourcefd, long linenumber, struct client *clients, struct settings *settings, struct ircdstate *ircdstate, struct channel *channels) {
+  debugprint(DEBUG_FULL, "doreplaylastspoke(): replaying from linenumber '%ld' to sourcefd '%d'.\n", linenumber, sourcefd);
+
+  FILE *fp;
+  char line[MAXCHAR];
+  char filename[PATH_MAX];
+  char outgoingmsg[MAXDATASIZE];
+
+  // Build path
+  if (!snprintf(filename, PATH_MAX, "%s/replay.log", settings->basedir)) {
+    debugprint(DEBUG_CRIT, "doreplaylastspoke(): error: couldn't prepare replay path, exiting!\n");
+    exit(1);
+  }
+
+  fp = fopen(filename, "r");
+
+  if (fp == NULL) {
+    debugprint(DEBUG_FULL, "error: doreplaylastspoke(): could not open replay log '%s'.\n", filename);
+    // Assume the file just doesn't exist yet - TODO - Interpret error codes to see what happened.
+    return 0;
+  }
+
+  // Announce the start
+  snprintf(outgoingmsg, MAXDATASIZE, "NOTICE %s :Starting log replay....", ircdstate->ircnick);
+  sendtoclient(sourcefd, outgoingmsg, clients, settings, 0);
+
+  long curlinenumber = -1; // Current line number of this file reading loop
+  while (fgets(line, MAXCHAR, fp) != NULL) {
+    curlinenumber++;
+    // Skip through the file until line number 'linenumber'...
+    if (curlinenumber < linenumber) {
+      continue;
+    }
+    // ...carry on once we've reached 'linenumber'
+
+    // Read the timestamp from the line
+    int timestamp = gettimestamp(line);
+
+    // Make sure and it wasn't before blabouncer launched...
+    if (timestamp < ircdstate->launchtime) {
+      // Don't replay if this replay line happened before blabouncer launched,
+      // to avoid weird synchronisation issues with uncertain events from before
+      // we launched.
+      debugprint(DEBUG_FULL, "doreplaylastspoke(): Ignoring line '%s' from before we launched.\n", line);
+      continue;
+    }
+
+    // Insert our formatted [HH:MM:SS] timestamp into the message
+    formattime(line, settings->replaydates);
+
+    strncpy(outgoingmsg, line, strlen(line));
+    outgoingmsg[strlen(line)] = '\0';
+
+    if (sanitisereplay(outgoingmsg, ircdstate, channels) < 1) {
+      continue;
+    }
+
+    debugprint(DEBUG_FULL, "doreplaylastspoke(): Sending replay line: '%s'.\n", outgoingmsg);
+    sendtoclient(sourcefd, outgoingmsg, clients, settings, 0);
+  }
+
+  // Announce the end
+  snprintf(outgoingmsg, MAXDATASIZE, "NOTICE %s :Log replay complete.", ircdstate->ircnick);
+  sendtoclient(sourcefd, outgoingmsg, clients, settings, 0);
+
+  return 1;
 }
 
 // Write the line 'str' to the replay log file after prepending it with
diff --git a/replay.h b/replay.h
index 039c131..dcf6771 100644
--- a/replay.h
+++ b/replay.h
@@ -38,13 +38,25 @@
 #define TIMELENF 11 // [HH:MM:SS] = 10 characters + 1 for null char
 #define DATETIMELEN 50 // Should be enough for a full datetime string // TODO - Is it!?  I think it will only ever be as long as [DD/MM/YY HH:MM:SS] (20 including null)
 
-int replaylines(int seconds, char *basedir);
+// Return the number of lines in the replay log since 'seconds' seconds ago, or -1 if there a problem.
+// 'basedir' is the directory in which to find 'replay.log'.
+int replaylinestime(int seconds, char *basedir);
 
 int readreplayline(int seconds, int linenum, char *str, struct settings *settings, struct ircdstate *ircdstate);
 
-// Returns the number of seconds ago that 'nick' last spoke, or -1 if there is a problem.
+// Returns the line number in the replay log file on which 'nick' last spoke, or -1 if there is a problem.
 // 'basedir' is the directory in which to find 'replay.log'.
-int lastspokesecondsago(char *nick, char *basedir);
+long lastspokelinenumber(char *nick, char *basedir);
+
+// Send the requested number of seconds worth of replay log lines to the requested client.
+// 'sourcefd' is the client to send to, and 'replayseconds' is the number of
+// seconds of replay log to replay.
+// Returns 1 for success or 0 for failure.
+int doreplaytime(int sourcefd, int replayseconds, struct client *clients, struct settings *settings, struct ircdstate *ircdstate, struct channel *channels);
+
+// Send replay log lines from line number 'linenumber' onwards, to client 'sourcefd'.
+// Returns 1 for success or 0 for failure.
+int doreplaylastspoke(int sourcefd, long linenumber, struct client *clients, struct settings *settings, struct ircdstate *ircdstate, struct channel *channels);
 
 int writereplayline(char *str, char *basedir);