From 6d80e988255bf8a76a51fa980c8e53e7a22dccce Mon Sep 17 00:00:00 2001
From: Oxore <oxore@protonmail.com>
Date: Thu, 3 Mar 2022 02:09:51 +0300
Subject: Impl basic key mapping, add single key mappings

---
 main.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 68 insertions(+), 26 deletions(-)

diff --git a/main.c b/main.c
index faf15b0..dbdef16 100644
--- a/main.c
+++ b/main.c
@@ -8,6 +8,31 @@
 #include <stdbool.h>
 #include <signal.h>
 
+enum mapping_type {
+    MT_SINGLE = 0,
+    MT_DOUBLE = 1,
+    MT_SINGLE_SINGLE = 2,
+    MT_DOUBLE_SINGLE = 3,
+    MT_SINGLE_DOUBLE = 4,
+    MT_DOUBLE_DOUBLE = 5,
+};
+
+// TODO Perhaps scancodes are necessary too
+struct mapping {
+    enum mapping_type type;
+    unsigned short first[2];
+    unsigned short second[2];
+    unsigned short key;
+};
+
+#define MAPPINGS_NUM 10
+struct mapping g_mapping[MAPPINGS_NUM] = {
+    { .type = MT_SINGLE, .first = { BTN_SOUTH }, .key = KEY_ENTER, },
+    { .type = MT_SINGLE, .first = { BTN_EAST }, .key = KEY_SPACE, },
+    { .type = MT_SINGLE, .first = { BTN_WEST }, .key = KEY_BACKSPACE, },
+    { .type = MT_SINGLE, .first = { BTN_NORTH }, .key = KEY_ESC, },
+};
+
 bool should_stop = false;
 
 void sigint_handler(int _value)
@@ -17,17 +42,40 @@ void sigint_handler(int _value)
     printf("SIGINT handled\n");
 }
 
+void setup_output_device(int fd) {
+    /*
+     * The ioctls below will enable the device that is about to be
+     * created, to pass key events, in this case the space key.
+     */
+    ioctl(fd, UI_SET_EVBIT, EV_KEY);
+    // TODO do not forget to register all keys that are gonna be supported in
+    // the mapping configuration
+    ioctl(fd, UI_SET_KEYBIT, KEY_SPACE);
+    ioctl(fd, UI_SET_KEYBIT, KEY_ENTER);
+    ioctl(fd, UI_SET_KEYBIT, KEY_ESC);
+    ioctl(fd, UI_SET_KEYBIT, KEY_BACKSPACE);
+    struct uinput_setup usetup;
+    memset(&usetup, 0, sizeof(usetup));
+    usetup.id.bustype = BUS_USB;
+    usetup.id.vendor = 0x1234; /* sample vendor */
+    usetup.id.product = 0x5678; /* sample product */
+    strcpy(usetup.name, "Example device");
+    ioctl(fd, UI_DEV_SETUP, &usetup);
+    ioctl(fd, UI_DEV_CREATE);
+}
+
 void emit(int fd, int type, int code, int val)
 {
-    struct input_event ie;
-
-    ie.type = type;
-    ie.code = code;
-    ie.value = val;
-    /* timestamp values below are ignored */
-    ie.time.tv_sec = 0;
-    ie.time.tv_usec = 0;
-
+    struct input_event ie = {
+        .type = type,
+        .code = code,
+        .value = val,
+        /* timestamp values below are ignored */
+        .time = {
+            .tv_sec = 0,
+            .tv_usec = 0,
+        },
+    };
     write(fd, &ie, sizeof(ie));
 }
 
@@ -52,22 +100,7 @@ int main(int argc, char *argv[])
     }
     signal(SIGINT, sigint_handler);
 
-    /*
-     * The ioctls below will enable the device that is about to be
-     * created, to pass key events, in this case the space key.
-     */
-    ioctl(ofd, UI_SET_EVBIT, EV_KEY);
-    ioctl(ofd, UI_SET_KEYBIT, KEY_SPACE);
-
-    struct uinput_setup usetup;
-    memset(&usetup, 0, sizeof(usetup));
-    usetup.id.bustype = BUS_USB;
-    usetup.id.vendor = 0x1234; /* sample vendor */
-    usetup.id.product = 0x5678; /* sample product */
-    strcpy(usetup.name, "Example device");
-
-    ioctl(ofd, UI_DEV_SETUP, &usetup);
-    ioctl(ofd, UI_DEV_CREATE);
+    setup_output_device(ofd);
 
     /*
      * On UI_DEV_CREATE the kernel will create the device node for this
@@ -84,6 +117,15 @@ int main(int argc, char *argv[])
         switch (ev.type) {
         case EV_KEY:
             printf("EV_KEY, code=%u, value=%d\n", ev.code, ev.value);
+            for (ssize_t i = 0; i < MAPPINGS_NUM; i++) {
+                struct mapping mapping = g_mapping[i];
+                if (mapping.type == MT_SINGLE && mapping.first[0] == ev.code && ev.value == 0) {
+                    emit(ofd, EV_KEY, mapping.key, 1);
+                    emit(ofd, EV_SYN, SYN_REPORT, 0);
+                    emit(ofd, EV_KEY, mapping.key, 0);
+                    emit(ofd, EV_SYN, SYN_REPORT, 0);
+                }
+            }
             break;
         case EV_ABS:
             /*
@@ -113,7 +155,7 @@ int main(int argc, char *argv[])
      * Give userspace some time to read the events before we destroy the
      * device with UI_DEV_DESTOY.
      */
-    sleep(1);
+    //sleep(1);
 
     ioctl(ofd, UI_DEV_DESTROY);
     close(ofd);
-- 
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