From a6bd24443139bf9e2745f42c42c2e956772e8eb8 Mon Sep 17 00:00:00 2001
From: CPunch <sethtstubbs@gmail.com>
Date: Fri, 4 Feb 2022 13:15:06 -0600
Subject: [PATCH] Added TaskService, ltask.[ch]

- cnc's main.c has an example of scheduling tasks
- switched to C11, might go back to C99 if i get the motivation
	to write a windows-specific getTime() implementation
---
 cnc/src/main.c      | 15 ++++++--
 lib/include/ltask.h | 32 ++++++++++++++++
 lib/src/ltask.c     | 93 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 137 insertions(+), 3 deletions(-)
 create mode 100644 lib/include/ltask.h
 create mode 100644 lib/src/ltask.c

diff --git a/cnc/src/main.c b/cnc/src/main.c
index 2c13083..79f9633 100644
--- a/cnc/src/main.c
+++ b/cnc/src/main.c
@@ -1,14 +1,23 @@
 #include <stdio.h>
 
+#include "ltask.h"
 #include "cnc.h"
 
+struct sLaika_taskService tService;
+
+void debugTask(struct sLaika_taskService *service, struct sLaika_task *task, clock_t currTick, void *uData) {
+    printf("hello !\n");
+}
+
 int main(int argv, char **argc) {
     struct sLaika_cnc *cnc = laikaC_newCNC(13337);
 
+    laikaT_initTaskService(&tService);
+    laikaT_newTask(&tService, 2000, debugTask, NULL);
+
     while (true) {
-        if (!laikaC_pollPeers(cnc, 1000)) {
-            LAIKA_DEBUG("no events!\n");
-        }
+        laikaC_pollPeers(cnc, laikaT_timeTillTask(&tService));
+        laikaT_pollTasks(&tService);
     }
 
     laikaC_freeCNC(cnc);
diff --git a/lib/include/ltask.h b/lib/include/ltask.h
new file mode 100644
index 0000000..7b8299c
--- /dev/null
+++ b/lib/include/ltask.h
@@ -0,0 +1,32 @@
+#ifndef LAIKA_TASK_H
+#define LAIKA_TASK_H
+
+#include <time.h>
+
+struct sLaika_task;
+struct sLaika_taskService;
+typedef void (*taskCallback)(struct sLaika_taskService *service, struct sLaika_task *task, clock_t currTick, void *uData);
+
+struct sLaika_task {
+    struct sLaika_task *next;
+    taskCallback callback;
+    void *uData;
+    long scheduled;
+};
+
+struct sLaika_taskService {
+    struct sLaika_task *headTask;
+};
+
+void laikaT_initTaskService(struct sLaika_taskService *service);
+void laikaT_cleanTaskService(struct sLaika_taskService *service);
+
+struct sLaika_task *laikaT_newTask(struct sLaika_taskService *service, int delta, taskCallback callback, void *uData);
+void laikaT_delTask(struct sLaika_taskService *service, struct sLaika_task *task);
+
+void laikaT_pollTasks(struct sLaika_taskService *service);
+
+/* will return the delta time in ms till the next event. -1 for no tasks scheduled */
+int laikaT_timeTillTask(struct sLaika_taskService *service);
+
+#endif
\ No newline at end of file
diff --git a/lib/src/ltask.c b/lib/src/ltask.c
new file mode 100644
index 0000000..73d5991
--- /dev/null
+++ b/lib/src/ltask.c
@@ -0,0 +1,93 @@
+#include "lmem.h"
+#include "ltask.h"
+
+/* this is the only reason C11 support is needed, i cba to write windows/linux specific stuff to get the current time in ms
+    also side note: microsoft? more like micropenis */
+long getTime() {
+    struct timespec ts;
+    timespec_get(&ts, TIME_UTC);
+    return ts.tv_sec*1000 + ts.tv_nsec/1000000; /* convert nanoseconds to milliseconds */
+}
+
+void laikaT_initTaskService(struct sLaika_taskService *service) {
+    service->headTask = NULL;
+}
+
+void laikaT_cleanTaskService(struct sLaika_taskService *service) {
+    struct sLaika_task *curr = service->headTask, *last;
+
+    /* walk though tasks, freeing all */
+    while (curr != NULL) {
+        last = curr;
+        curr = curr->next;
+        laikaM_free(last);
+    }
+}
+
+struct sLaika_task *laikaT_newTask(struct sLaika_taskService *service, int delta, taskCallback callback, void *uData) {
+    struct sLaika_task *curr = service->headTask, *last = NULL, *task = laikaM_malloc(sizeof(struct sLaika_task));
+
+    task->callback = callback;
+    task->uData = uData;
+    task->scheduled = getTime() + delta;
+
+    /* search list for event for which we're scheduled before */
+    while (curr != NULL && curr->scheduled < task->scheduled) {
+        last = curr;
+        curr = curr->next;
+    }
+
+    /* if we stopped at the first head item, set it */
+    if (curr == service->headTask) {
+        task->next = service->headTask;
+        service->headTask = task;
+    } else {
+        /* add to list */
+        task->next = curr;
+        if (last)
+            last->next = task;
+    }
+}
+
+void laikaT_delTask(struct sLaika_taskService *service, struct sLaika_task *task) {
+    struct sLaika_task *curr = service->headTask, *last = NULL;
+
+    if (task == service->headTask) {
+        service->headTask = task->next;
+    } else {
+        /* find in list */
+        while (curr != task) {
+            last = curr;
+            curr = curr->next;
+        }
+
+        /* unlink */
+        last->next = task->next;
+    }
+
+    laikaM_free(task);
+}
+
+void laikaT_pollTasks(struct sLaika_taskService *service) {
+    struct sLaika_task *last, *curr = service->headTask;
+    clock_t currTick = getTime();
+
+    /* run each task, list is already sorted from closest scheduled task to furthest */
+    while (curr != NULL && curr->scheduled < currTick) { /* if scheduled time is greater than currTime, all events that follow are also not scheduled yet */
+        /* dispatch task callback */
+        curr->callback(service, curr, currTick, curr->uData);
+        
+        /* walk to next task and free */
+        last = curr;
+        curr = curr->next;
+        laikaT_delTask(service, last);
+    }
+}
+
+/* will return the delta time in ms till the next event. -1 for no tasks scheduled */
+int laikaT_timeTillTask(struct sLaika_taskService *service) {
+    if (service->headTask)
+        return service->headTask->scheduled - getTime();
+    else
+        return -1; /* no tasks scheduled */
+}
\ No newline at end of file