use core::{ffi::c_void, mem};
use minifb::{Key, Window, WindowOptions};
use once_cell::sync::Lazy;
use windows_dll::dll;

const WIDTH: usize = 640;
const HEIGHT: usize = 360;

fn main() {
    let mut buffer: Vec<u32> = vec![0; WIDTH * HEIGHT];

    let mut window = Window::new(
        "Test - ESC to exit",
        WIDTH,
        HEIGHT,
        WindowOptions::default(),
    )
    .unwrap_or_else(|e| {
        panic!("{}", e);
    });
    dark_dwm_decorations(window.get_window_handle(), true);

    // Limit to max ~60 fps update rate
    window.limit_update_rate(Some(std::time::Duration::from_micros(16600)));

    while window.is_open() && !window.is_key_down(Key::Escape) {
        for i in buffer.iter_mut() {
            *i = 0; // write something more funny here!
        }

        // We unwrap here as we want this code to exit if it fails. Real applications may want to handle this in a different way
        window.update_with_buffer(&buffer, WIDTH, HEIGHT).unwrap();
    }
}

use platform::dark_dwm_decorations;

#[cfg(feature = "winapi")]
mod platform {
    use super::*;
    use winapi::shared::{
        basetsd::SIZE_T,
        minwindef::{BOOL, DWORD, FALSE, ULONG},
        ntdef::{NTSTATUS, NT_SUCCESS, PVOID, WCHAR},
        windef::HWND,
    };

    static WIN10_BUILD: Lazy<Option<DWORD>> = Lazy::new(|| {
        #[dll(ntdll)]
        extern "system" {
            #[allow(non_snake_case)]
            fn RtlGetVersion(lpVersionInformation: *mut OSVERSIONINFOW) -> NTSTATUS;
        }

        #[allow(non_snake_case)]
        #[repr(C)]
        struct OSVERSIONINFOW {
            dwOSVersionInfoSize: ULONG,
            dwMajorVersion: ULONG,
            dwMinorVersion: ULONG,
            dwBuildNumber: ULONG,
            dwPlatformId: ULONG,
            szCSDVersion: [WCHAR; 128],
        }
        unsafe {
            if !RtlGetVersion::exists() {
                return None;
            }
            let mut version_info = OSVERSIONINFOW {
                dwOSVersionInfoSize: 0,
                dwMajorVersion: 0,
                dwMinorVersion: 0,
                dwBuildNumber: 0,
                dwPlatformId: 0,
                szCSDVersion: [0; 128],
            };
            let status = RtlGetVersion(&mut version_info);

            if NT_SUCCESS(status)
                && version_info.dwMajorVersion == 10
                && version_info.dwMinorVersion == 0
            {
                Some(version_info.dwBuildNumber)
            } else {
                None
            }
        }
    });

    static DARK_MODE_SUPPORTED: Lazy<bool> = Lazy::new(|| match *WIN10_BUILD {
        Some(build) => build >= 17763,
        None => false,
    });

    pub fn dark_dwm_decorations(minifb_hwnd: *mut c_void, enable_dark_mode: bool) -> bool {
        let hwnd = minifb_hwnd as HWND;

        #[allow(non_snake_case)]
        type WINDOWCOMPOSITIONATTRIB = u32;
        const WCA_USEDARKMODECOLORS: WINDOWCOMPOSITIONATTRIB = 26;

        #[allow(non_snake_case)]
        #[repr(C)]
        struct WINDOWCOMPOSITIONATTRIBDATA {
            Attrib: WINDOWCOMPOSITIONATTRIB,
            pvData: PVOID,
            cbData: SIZE_T,
        }

        #[dll(user32)]
        extern "system" {
            #[allow(non_snake_case)]
            fn SetWindowCompositionAttribute(
                h_wnd: HWND,
                data: *mut WINDOWCOMPOSITIONATTRIBDATA,
            ) -> BOOL;
        }

        if *DARK_MODE_SUPPORTED && unsafe { SetWindowCompositionAttribute::exists() } {
            unsafe {
                let mut is_dark_mode_bigbool = enable_dark_mode as BOOL;
                let mut data = WINDOWCOMPOSITIONATTRIBDATA {
                    Attrib: WCA_USEDARKMODECOLORS,
                    pvData: &mut is_dark_mode_bigbool as *mut _ as _,
                    cbData: mem::size_of::<BOOL>(),
                };

                let status = SetWindowCompositionAttribute(hwnd, &mut data);

                status != FALSE
            }
        } else {
            false
        }
    }
}

#[cfg(feature = "windows")]
mod platform {
    use super::*;
    use windows::Win32::Foundation::{BOOL, HWND, NTSTATUS};

    type DWORD = u32;
    type ULONG = u32;
    type WCHAR = u16;
    type PVOID = *mut c_void;
    #[allow(non_camel_case_types)]
    type SIZE_T = usize;

    static WIN10_BUILD: Lazy<Option<DWORD>> = Lazy::new(|| {
        #[dll(ntdll)]
        extern "system" {
            #[allow(non_snake_case)]
            fn RtlGetVersion(lpVersionInformation: *mut OSVERSIONINFOW) -> NTSTATUS;
        }

        #[allow(non_snake_case)]
        #[repr(C)]
        struct OSVERSIONINFOW {
            dwOSVersionInfoSize: ULONG,
            dwMajorVersion: ULONG,
            dwMinorVersion: ULONG,
            dwBuildNumber: ULONG,
            dwPlatformId: ULONG,
            szCSDVersion: [WCHAR; 128],
        }
        unsafe {
            if !RtlGetVersion::exists() {
                return None;
            }
            let mut version_info = OSVERSIONINFOW {
                dwOSVersionInfoSize: 0,
                dwMajorVersion: 0,
                dwMinorVersion: 0,
                dwBuildNumber: 0,
                dwPlatformId: 0,
                szCSDVersion: [0; 128],
            };
            let status = RtlGetVersion(&mut version_info);

            if status.is_ok()
                && version_info.dwMajorVersion == 10
                && version_info.dwMinorVersion == 0
            {
                Some(version_info.dwBuildNumber)
            } else {
                None
            }
        }
    });

    static DARK_MODE_SUPPORTED: Lazy<bool> = Lazy::new(|| match *WIN10_BUILD {
        Some(build) => build >= 17763,
        None => false,
    });

    pub fn dark_dwm_decorations(minifb_hwnd: *mut c_void, enable_dark_mode: bool) -> bool {
        let hwnd = HWND(minifb_hwnd as _);

        #[allow(non_snake_case)]
        type WINDOWCOMPOSITIONATTRIB = u32;
        const WCA_USEDARKMODECOLORS: WINDOWCOMPOSITIONATTRIB = 26;

        #[allow(non_snake_case)]
        #[repr(C)]
        struct WINDOWCOMPOSITIONATTRIBDATA {
            Attrib: WINDOWCOMPOSITIONATTRIB,
            pvData: PVOID,
            cbData: SIZE_T,
        }

        #[dll(user32)]
        extern "system" {
            #[allow(non_snake_case)]
            fn SetWindowCompositionAttribute(
                h_wnd: HWND,
                data: *mut WINDOWCOMPOSITIONATTRIBDATA,
            ) -> BOOL;
        }

        if *DARK_MODE_SUPPORTED && unsafe { SetWindowCompositionAttribute::exists() } {
            unsafe {
                let mut is_dark_mode_bigbool = BOOL::from(enable_dark_mode);
                let mut data = WINDOWCOMPOSITIONATTRIBDATA {
                    Attrib: WCA_USEDARKMODECOLORS,
                    pvData: &mut is_dark_mode_bigbool as *mut _ as _,
                    cbData: mem::size_of::<BOOL>(),
                };

                let status = SetWindowCompositionAttribute(hwnd, &mut data);

                status.as_bool()
            }
        } else {
            false
        }
    }
}