package thread

import "core:runtime"
import "core:mem"
import "intrinsics"

_ :: intrinsics;

Thread_Proc :: #type proc(^Thread);

MAX_USER_ARGUMENTS :: 8;

Thread :: struct {
	using specific: Thread_Os_Specific,
	procedure:      Thread_Proc,
	data:           rawptr,
	user_index:     int,
	user_args:      [MAX_USER_ARGUMENTS]rawptr,

	init_context: Maybe(runtime.Context),


	creation_allocator: mem.Allocator,
}

#assert(size_of(Thread{}.user_index) == size_of(uintptr));

Thread_Priority :: enum {
	Normal,
	Low,
	High,
}

create :: proc(procedure: Thread_Proc, priority := Thread_Priority.Normal) -> ^Thread {
	return _create(procedure, priority);
}
destroy :: proc(thread: ^Thread) {
	_destroy(thread);
}

start :: proc(thread: ^Thread) {
	_start(thread);
}

is_done :: proc(thread: ^Thread) -> bool {
	return _is_done(thread);
}


join :: proc(thread: ^Thread) {
	_join(thread);
}


join_mulitple :: proc(threads: ..^Thread) {
	_join_multiple(..threads);
}

terminate :: proc(thread: ^Thread, exit_code: int) {
	_terminate(thread, exit_code);
}

yield :: proc() {
	_yield();
}



run :: proc(fn: proc(), init_context: Maybe(runtime.Context) = nil, priority := Thread_Priority.Normal) {
	thread_proc :: proc(t: ^Thread) {
		fn := cast(proc())t.data;
		fn();
		destroy(t);
	}
	t := create(thread_proc, priority);
	t.data = rawptr(fn);
	t.init_context = init_context;
	start(t);
}

run_with_data :: proc(data: rawptr, fn: proc(data: rawptr), init_context: Maybe(runtime.Context) = nil, priority := Thread_Priority.Normal) {
	thread_proc :: proc(t: ^Thread) {
		fn := cast(proc(rawptr))t.data;
		assert(t.user_index >= 1);
		data := t.user_args[0];
		fn(data);
		destroy(t);
	}
	t := create(thread_proc, priority);
	t.data = rawptr(fn);
	t.user_index = 1;
	t.user_args = data;
	t.init_context = init_context;
	start(t);
}

run_with_poly_data :: proc(data: $T, fn: proc(data: T), init_context: Maybe(runtime.Context) = nil, priority := Thread_Priority.Normal)
	where size_of(T) <= size_of(rawptr) {
	thread_proc :: proc(t: ^Thread) {
		fn := cast(proc(T))t.data;
		assert(t.user_index >= 1);
		data := (^T)(&t.user_args[0])^;
		fn(data);
		destroy(t);
	}
	t := create(thread_proc, priority);
	t.data = rawptr(fn);
	t.user_index = 1;
	data := data;
	mem.copy(&t.user_args[0], &data, size_of(data));
	t.init_context = init_context;
	start(t);
}

run_with_poly_data2 :: proc(arg1: $T1, arg2: $T2, fn: proc(T1, T2), init_context: Maybe(runtime.Context) = nil, priority := Thread_Priority.Normal)
	where size_of(T1) <= size_of(rawptr),
	      size_of(T2) <= size_of(rawptr) {
	thread_proc :: proc(t: ^Thread) {
		fn := cast(proc(T1, T2))t.data;
		assert(t.user_index >= 2);
		arg1 := (^T1)(&t.user_args[0])^;
		arg2 := (^T2)(&t.user_args[1])^;
		fn(arg1, arg2);
		destroy(t);
	}
	t := create(thread_proc, priority);
	t.data = rawptr(fn);
	t.user_index = 2;
	arg1, arg2 := arg1, arg2;
	mem.copy(&t.user_args[0], &arg1, size_of(arg1));
	mem.copy(&t.user_args[1], &arg2, size_of(arg2));
	t.init_context = init_context;
	start(t);
}

run_with_poly_data3 :: proc(arg1: $T1, arg2: $T2, arg3: $T3, fn: proc(arg1: T1, arg2: T2, arg3: T3), init_context: Maybe(runtime.Context) = nil, priority := Thread_Priority.Normal)
	where size_of(T1) <= size_of(rawptr),
	      size_of(T2) <= size_of(rawptr),
	      size_of(T3) <= size_of(rawptr) {
	thread_proc :: proc(t: ^Thread) {
		fn := cast(proc(T1, T2, T3))t.data;
		assert(t.user_index >= 3);
		arg1 := (^T1)(&t.user_args[0])^;
		arg2 := (^T2)(&t.user_args[1])^;
		arg3 := (^T3)(&t.user_args[2])^;
		fn(arg1, arg2, arg3);
		destroy(t);
	}
	t := create(thread_proc, priority);
	t.data = rawptr(fn);
	t.user_index = 3;
	arg1, arg2, arg3 := arg1, arg2, arg3;
	mem.copy(&t.user_args[0], &arg1, size_of(arg1));
	mem.copy(&t.user_args[1], &arg2, size_of(arg2));
	mem.copy(&t.user_args[2], &arg3, size_of(arg3));
	t.init_context = init_context;
	start(t);
}
run_with_poly_data4 :: proc(arg1: $T1, arg2: $T2, arg3: $T3, arg4: $T4, fn: proc(arg1: T1, arg2: T2, arg3: T3, arg4: T4), init_context: Maybe(runtime.Context) = nil, priority := Thread_Priority.Normal)
	where size_of(T1) <= size_of(rawptr),
	      size_of(T2) <= size_of(rawptr),
	      size_of(T3) <= size_of(rawptr) {
	thread_proc :: proc(t: ^Thread) {
		fn := cast(proc(T1, T2, T3, T4))t.data;
		assert(t.user_index >= 4);
		arg1 := (^T1)(&t.user_args[0])^;
		arg2 := (^T2)(&t.user_args[1])^;
		arg3 := (^T3)(&t.user_args[2])^;
		arg4 := (^T4)(&t.user_args[3])^;
		fn(arg1, arg2, arg3, arg4);
		destroy(t);
	}
	t := create(thread_proc, priority);
	t.data = rawptr(fn);
	t.user_index = 4;
	arg1, arg2, arg3, arg4 := arg1, arg2, arg3, arg4;
	mem.copy(&t.user_args[0], &arg1, size_of(arg1));
	mem.copy(&t.user_args[1], &arg2, size_of(arg2));
	mem.copy(&t.user_args[2], &arg3, size_of(arg3));
	mem.copy(&t.user_args[3], &arg4, size_of(arg4));
	t.init_context = init_context;
	start(t);
}



create_and_start :: proc(fn: Thread_Proc, init_context: Maybe(runtime.Context) = nil, priority := Thread_Priority.Normal) -> ^Thread {
	t := create(fn, priority);
	t.init_context = init_context;
	start(t);
	return t;
}
