use inkwell::context::Context;
use inkwell::AddressSpace;

fn main() {
    let context = Context::create();
    let module = context.create_module("my_module");
    let i32_type = context.i32_type();
    let i32_ptr_type = context.i32_type().ptr_type(AddressSpace::Generic);

    let struct_type = context.struct_type(&[i32_type.into(), i32_type.into()], false);

    unsafe { // just being lazy with gep calls.
        let init = struct_type.ptr_type(AddressSpace::Generic).const_zero().const_gep(&[
            i32_type.const_int(0, false).into(),
            i32_type.const_int(1, false).into()
        ]);

        let a = module.add_global(i32_ptr_type, Some(AddressSpace::Generic), "a");
        a.set_constant(true);
        a.set_initializer(&init);
        // Good, normal:
        // @a = constant i32* getelementptr ({ i32, i32 }, { i32, i32 }* null, i32 0, i32 1)

        let b = module.add_global(i32_type, Some(AddressSpace::Generic), "b");
        b.set_constant(true);
        b.set_initializer(&init.const_to_int(i32_type));
        // Why is GEP only passed one index? Where did my 0 go? -----------V
        // @b = constant i32 ptrtoint (i32* getelementptr (i32, i32* null, i32 1) to i32)
        // Types are wrong?^             ^

        let c = module.add_global(i32_ptr_type, Some(AddressSpace::Generic), "c");
        c.set_constant(true);
        c.set_initializer(&init);
        // Same as a - just showing the initializer isn't mutated or unusable or anything.
        // @c = constant i32* getelementptr ({ i32, i32 }, { i32, i32 }* null, i32 0, i32 1)
    }

    println!("{}", module.print_to_string().to_string());
    // This is where I got the above samples. Here's the whole output:
    // ; ModuleID = 'my_module'
    // source_filename = "my_module"
    //
    // @a = constant i32* getelementptr ({ i32, i32 }, { i32, i32 }* null, i32 0, i32 1)
    // @b = constant i32 ptrtoint (i32* getelementptr (i32, i32* null, i32 1) to i32)
    // @c = constant i32* getelementptr ({ i32, i32 }, { i32, i32 }* null, i32 0, i32 1)

    module.verify().unwrap();
    // No errors.

    // This instantly segfaults. Seems using i64s is not valid for the indexing.
    unsafe {
        struct_type.ptr_type(AddressSpace::Generic).const_zero().const_gep(&[
            context.i64_type().const_int(0, false).into(),
            context.i64_type().const_int(1, false).into(),
        ]);
    }
}