// M2.3 — `#extends ForeignClass` method-resolution chaining.
//
// When `obj.method()` is called on a foreign-class pointer and
// `method` isn't declared directly on the receiver's class, the
// compiler walks the `#extends` chain to find an ancestor that
// declared it. The runtime dispatch path is unchanged —
// objc_msgSend handles the class-hierarchy lookup by isa at
// runtime. The chain walk is purely about source-level
// resolution (selector mangling, return type, arity check).

#import "modules/std.sx";
#import "modules/compiler.sx";
#import "modules/std/objc.sx";

NSObjectBase :: #foreign #objc_class("NSObject") {
    alloc :: () -> *NSObjectBase;
    init  :: (self: *NSObjectBase) -> *NSObjectBase;
    hash  :: (self: *NSObjectBase) -> u64;
}

// Sx-defined class that extends a foreign one. M1.2 registers
// the class at module init; `hash` is reached via the M2.3 chain
// walk through NSObjectBase, then dispatched by objc_msgSend.
SxThing :: #objc_class("SxThing") {
    #extends NSObjectBase;
    counter: s32;

    alloc :: () -> *SxThing;
    init  :: (self: *SxThing) -> *SxThing;
}

// And a chain-of-three: SxLeaf → SxMiddle → NSObjectBase.
SxMiddle :: #objc_class("SxMiddle") {
    #extends NSObjectBase;
    alloc :: () -> *SxMiddle;
    init  :: (self: *SxMiddle) -> *SxMiddle;
}
SxLeaf :: #objc_class("SxLeaf") {
    #extends SxMiddle;
    alloc :: () -> *SxLeaf;
    init  :: (self: *SxLeaf) -> *SxLeaf;
}

main :: () -> s32 {
    inline if OS == .macos {
        // 1-level chain: SxThing → NSObjectBase.
        t := SxThing.alloc().init();
        h_t : u64 = t.hash();
        if h_t == 0 { print("FAIL: SxThing.hash returned 0\n"); return 1; }

        // 2-level chain: SxLeaf → SxMiddle → NSObjectBase.
        l := SxLeaf.alloc().init();
        h_l : u64 = l.hash();
        if h_l == 0 { print("FAIL: SxLeaf.hash returned 0\n"); return 1; }

        print("extends chain: SxThing.hash=ok, SxLeaf.hash=ok\n");
    }
    inline if OS != .macos {
        print("extends chain: SxThing.hash=ok, SxLeaf.hash=ok\n");
    }
    0
}