diff --git a/src/ai/api/ai_log.cpp b/src/ai/api/ai_log.cpp
new file mode 100644
--- /dev/null
+++ b/src/ai/api/ai_log.cpp
@@ -0,0 +1,84 @@
+/* $Id$ */
+
+/** @file ai_log.cpp Implementation of AILog. */
+
+#include "ai_log.hpp"
+#include "../../core/alloc_func.hpp"
+#include "../../company_func.h"
+#include "../../debug.h"
+#include "../../window_func.h"
+
+/* static */ void AILog::Info(const char *message)
+{
+	AILog::Log(LOG_INFO, message);
+}
+
+/* static */ void AILog::Warning(const char *message)
+{
+	AILog::Log(LOG_WARNING, message);
+}
+
+/* static */ void AILog::Error(const char *message)
+{
+	AILog::Log(LOG_ERROR, message);
+}
+
+/* static */ void AILog::Log(AILog::AILogType level, const char *message)
+{
+	if (AIObject::GetLogPointer() == NULL) {
+		AIObject::GetLogPointer() = new LogData();
+		LogData *log = (LogData *)AIObject::GetLogPointer();
+
+		log->lines = CallocT<char *>(80);
+		log->type = CallocT<AILog::AILogType>(80);
+		log->count = 80;
+		log->pos = log->count;
+		log->used = 0;
+	}
+	LogData *log = (LogData *)AIObject::GetLogPointer();
+
+	/* Go to the next log-line */
+	log->pos = (log->pos + 1) % log->count;
+
+	if (log->used != log->count) log->used++;
+
+	/* Free last message, and write new message */
+	free(log->lines[log->pos]);
+	log->lines[log->pos] = strdup(message);
+	log->type[log->pos] = level;
+
+	/* Cut string after first \n */
+	char *p;
+	while ((p = strchr(log->lines[log->pos], '\n')) != NULL) {
+		*p = '\0';
+		break;
+	}
+
+	char logc;
+
+	switch (level) {
+		case LOG_SQ_ERROR: logc = 'S'; break;
+		case LOG_ERROR:    logc = 'E'; break;
+		case LOG_SQ_INFO:  logc = 'P'; break;
+		case LOG_WARNING:  logc = 'W'; break;
+		case LOG_INFO:     logc = 'I'; break;
+		default:           logc = '?'; break;
+	}
+
+	/* Also still print to debug window */
+	DEBUG(ai, level, "[%d] [%c] %s", (uint)_current_company, logc, log->lines[log->pos]);
+	InvalidateWindowData(WC_AI_DEBUG, 0, _current_company);
+}
+
+/* static */ void AILog::FreeLogPointer()
+{
+	LogData *log = (LogData *)AIObject::GetLogPointer();
+
+	for (int i = 0; i < log->count; i++) {
+		free(log->lines[i]);
+	}
+
+	free(log->lines);
+	free(log->type);
+	delete log;
+}