From 3ebc370ca45f34705d1e6f028180306e6a7a15e0 Mon Sep 17 00:00:00 2001
From: Sara <sara@saragerretsen.nl>
Date: Wed, 22 Nov 2023 11:46:46 +0100
Subject: [PATCH] added state machine

---
 core/src/state.h         | 30 ++++++++++++++++++++++++++++
 core/src/state_machine.c | 42 ++++++++++++++++++++++++++++++++++++++++
 core/src/state_machine.h | 15 ++++++++++++++
 3 files changed, 87 insertions(+)
 create mode 100644 core/src/state.h
 create mode 100644 core/src/state_machine.c
 create mode 100644 core/src/state_machine.h

diff --git a/core/src/state.h b/core/src/state.h
new file mode 100644
index 0000000..5e281fa
--- /dev/null
+++ b/core/src/state.h
@@ -0,0 +1,30 @@
+#ifndef _fencer_state_h
+#define _fencer_state_h
+
+#include "typeclass_helpers.h"
+
+typedef struct State State;
+
+struct State {
+    void (*const enter)(void* data);
+    void (*const exit)(void* data);
+    void (*const update)(void* data, float dt);
+    const State* (*const next)(void* data);
+};
+
+#define DefineState(_StateName, enter_fn, exit_fn, update_fn, next_fn)\
+static inline const State* _StateName() {\
+    TC_FN_TYPECHECK(void, enter_fn, void*);\
+    TC_FN_TYPECHECK(void, exit_fn, void*);\
+    TC_FN_TYPECHECK(void, update_fn, void*, float);\
+    TC_FN_TYPECHECK(const State*, next_fn, void*);\
+    static const State instance = {\
+        .enter = (void(*const)(void*)) enter_fn,\
+        .exit = (void(*const)(void*)) exit_fn,\
+        .update = (void(*const)(void*, float)) update_fn,\
+        .next = (const State*(*const)(void*)) next_fn\
+    };\
+    return instance;\
+}\
+
+#endif // !_fencer_state_h
diff --git a/core/src/state_machine.c b/core/src/state_machine.c
new file mode 100644
index 0000000..23d6ace
--- /dev/null
+++ b/core/src/state_machine.c
@@ -0,0 +1,42 @@
+#include "state_machine.h"
+#include "stdlib.h"
+
+struct StateMachine {
+    const State* current_state;
+    void* data;
+};
+
+StateMachine* state_machine_init(void* data, const State* start_state) {
+    StateMachine* self = malloc(sizeof(StateMachine));
+    *self = (StateMachine){
+        .current_state = start_state,
+        .data = data
+    };
+
+    self->current_state->enter(self->data);
+
+    return self;
+}
+
+void state_machine_destroy(StateMachine* self) {
+    self->current_state->exit(self->data);
+    free(self);
+}
+
+void state_machine_set_state(StateMachine* self, const State* state) {
+    self->current_state->exit(self->data);
+    self->current_state = state;
+    self->current_state->enter(self->data);
+}
+
+const State* state_machine_get_state(StateMachine* self) {
+    return self->current_state;
+}
+
+void state_machine_update(StateMachine* self, float dt) {
+    self->current_state->update(self->data, dt);
+    const State* next = self->current_state->next(self->data);
+
+    if(next != self->current_state)
+        state_machine_set_state(self, next);
+}
diff --git a/core/src/state_machine.h b/core/src/state_machine.h
new file mode 100644
index 0000000..6e5a414
--- /dev/null
+++ b/core/src/state_machine.h
@@ -0,0 +1,15 @@
+#ifndef _fencer_state_machine_h
+#define _fencer_state_machine_h
+
+#include "state.h"
+
+typedef struct StateMachine StateMachine;
+
+extern StateMachine* state_machine_init(void* data, const State* start_state);
+extern void state_machine_destroy(StateMachine* self);
+
+extern void state_machine_set_state(StateMachine* self, const State* state);
+extern const State* state_machine_get_current_state(StateMachine* self);
+extern void state_machine_update(StateMachine* self, float dt);
+
+#endif // !_fencer_state_machine_h