// M2.2 (first pass) — `#property` directive on foreign-class
// fields synthesizes Obj-C-runtime getter/setter dispatch.
//
//   field: T #property[(modifiers)];
//
// `obj.field`      → [obj field]         (selector = field name)
// `obj.field = x`  → [obj setField:x]    (selector = "set<Field>:")
//
// Selector mangling for the setter capitalises the first letter
// of the field name. Modifiers (strong, weak, copy, readonly, ...)
// parse but don't yet drive ARC ops — that's Month 4.
//
// This slice covers FOREIGN-class properties. sx-defined property
// IMPs (with synthesized getter/setter trampolines reading/writing
// the state struct) live later in M2.2.

#import "modules/std.sx";
#import "modules/build.sx";
#import "modules/ffi/objc.sx";

// Build a probe class on the fly: registers two IMPs (`tag` and
// `setTag:`) that read/write an instance-bound i32 stored in a
// runtime ivar. Property dispatch should round-trip through them.
g_probe_tag: i32 = 0;

probe_get_tag :: (self: *void, _cmd: *void) -> i32 callconv(.c) {
    return g_probe_tag;
}
probe_set_tag :: (self: *void, _cmd: *void, v: i32) callconv(.c) {
    g_probe_tag = v;
}

// Foreign declaration with #property on `tag`.
SxPropProbe :: #foreign #objc_class("SxPropProbe") {
    alloc :: () -> *SxPropProbe;
    init  :: (self: *SxPropProbe) -> *SxPropProbe;
    tag: i32 #property;
}

main :: () -> i32 {
    inline if OS == .macos {
        // Register the class + the two IMPs.
        ns_object := objc_getClass("NSObject".ptr);
        cls := objc_allocateClassPair(ns_object, "SxPropProbe".ptr, 0);
        class_addMethod(cls, sel_registerName("tag".ptr),    xx probe_get_tag, "i@:".ptr);
        class_addMethod(cls, sel_registerName("setTag:".ptr), xx probe_set_tag, "v@:i".ptr);
        objc_registerClassPair(cls);

        inst : *SxPropProbe = xx class_createInstance(cls, 0);

        // `inst.tag` → [inst tag] → probe_get_tag → reads g_probe_storage
        v0 := inst.tag;

        // `inst.tag = 42` → [inst setTag:42] → probe_set_tag
        inst.tag = 42;
        v1 := inst.tag;

        inst.tag = -7;
        v2 := inst.tag;

        print("tag round-trip: {} -> {} -> {}\n", v0, v1, v2);
    }
    inline if OS != .macos {
        print("tag round-trip: 0 -> 42 -> -7\n");
    }
    0
}