package zenity

import (
	"context"
	"sync"
	"syscall"
	"unsafe"

	"github.com/ncruces/zenity/internal/win"
)

func progress(opts options) (ProgressDialog, error) {
	if opts.title == nil {
		opts.title = ptr("")
	}
	if opts.okLabel == nil {
		opts.okLabel = ptr("OK")
	}
	if opts.cancelLabel == nil {
		opts.cancelLabel = ptr("Cancel")
	}
	if opts.maxValue == 0 {
		opts.maxValue = 100
	}
	if opts.ctx == nil {
		opts.ctx = context.Background()
	} else if cerr := opts.ctx.Err(); cerr != nil {
		return nil, cerr
	}

	dlg := &progressDialog{
		done:  make(chan struct{}),
		max:   opts.maxValue,
		close: opts.autoClose,
	}
	dlg.init.Add(1)

	go func() {
		dlg.err = dlg.setup(opts)
		close(dlg.done)
	}()

	dlg.init.Wait()
	return dlg, nil
}

type progressDialog struct {
	init  sync.WaitGroup
	done  chan struct{}
	err   error
	max   int
	close bool

	wnd       win.HWND
	textCtl   win.HWND
	progCtl   win.HWND
	okBtn     win.HWND
	cancelBtn win.HWND
	extraBtn  win.HWND
	font      font
}

func (d *progressDialog) Text(text string) error {
	select {
	default:
		win.SetWindowText(d.textCtl, strptr(text))
		return nil
	case <-d.done:
		return d.err
	}
}

func (d *progressDialog) Value(value int) error {
	if value >= d.max && d.close {
		return d.Close()
	}
	select {
	default:
		win.SendMessage(d.progCtl, win.PBM_SETPOS, uintptr(value), 0)
		if value >= d.max {
			win.EnableWindow(d.okBtn, true)
		}
		return nil
	case <-d.done:
		return d.err
	}
}

func (d *progressDialog) MaxValue() int {
	return d.max
}

func (d *progressDialog) Done() <-chan struct{} {
	return d.done
}

func (d *progressDialog) Complete() error {
	select {
	default:
		win.SetWindowLong(d.progCtl, win.GWL_STYLE, win.WS_CHILD|win.WS_VISIBLE|win.PBS_SMOOTH)
		win.SendMessage(d.progCtl, win.PBM_SETRANGE32, 0, 1)
		win.SendMessage(d.progCtl, win.PBM_SETPOS, 1, 0)
		win.EnableWindow(d.okBtn, true)
		win.EnableWindow(d.cancelBtn, false)
		return nil
	case <-d.done:
		return d.err
	}
}

func (d *progressDialog) Close() error {
	win.SendMessage(d.wnd, win.WM_SYSCOMMAND, win.SC_CLOSE, 0)
	<-d.done
	if d.err == ErrCanceled {
		return nil
	}
	return d.err
}

func (dlg *progressDialog) setup(opts options) error {
	var once sync.Once
	defer once.Do(dlg.init.Done)

	owner, _ := opts.attach.(win.HWND)
	defer setup(owner)()
	dlg.font = getFont()
	defer dlg.font.delete()
	icon, _ := getIcon(opts.windowIcon)
	defer icon.delete()

	if opts.ctx != nil && opts.ctx.Err() != nil {
		return opts.ctx.Err()
	}

	instance, err := win.GetModuleHandle(nil)
	if err != nil {
		return err
	}

	cls, err := registerClass(instance, icon.handle, syscall.NewCallback(progressProc))
	if err != nil {
		return err
	}
	defer win.UnregisterClass(cls, instance)

	dlg.wnd, _ = win.CreateWindowEx(_WS_EX_ZEN_DIALOG,
		cls, strptr(*opts.title), _WS_ZEN_DIALOG,
		win.CW_USEDEFAULT, win.CW_USEDEFAULT,
		281, 133, owner, 0, instance, unsafe.Pointer(dlg))

	dlg.textCtl, _ = win.CreateWindowEx(0,
		strptr("STATIC"), nil, _WS_ZEN_LABEL,
		12, 10, 241, 16, dlg.wnd, 0, instance, nil)

	var flags uint32 = win.WS_CHILD | win.WS_VISIBLE | win.PBS_SMOOTH
	if opts.maxValue < 0 {
		flags |= win.PBS_MARQUEE
	}
	dlg.progCtl, _ = win.CreateWindowEx(0,
		strptr(win.PROGRESS_CLASS),
		nil, flags,
		12, 30, 241, 16, dlg.wnd, 0, instance, nil)

	if !opts.noCancel || !opts.autoClose {
		dlg.okBtn, _ = win.CreateWindowEx(0,
			strptr("BUTTON"), strptr(quoteAccelerators(*opts.okLabel)),
			_WS_ZEN_BUTTON|win.BS_DEFPUSHBUTTON|win.WS_DISABLED,
			12, 58, 75, 24, dlg.wnd, win.IDOK, instance, nil)
	}
	if !opts.noCancel {
		dlg.cancelBtn, _ = win.CreateWindowEx(0,
			strptr("BUTTON"), strptr(quoteAccelerators(*opts.cancelLabel)),
			_WS_ZEN_BUTTON,
			12, 58, 75, 24, dlg.wnd, win.IDCANCEL, instance, nil)
	}
	if opts.extraButton != nil {
		dlg.extraBtn, _ = win.CreateWindowEx(0,
			strptr("BUTTON"), strptr(quoteAccelerators(*opts.extraButton)),
			_WS_ZEN_BUTTON,
			12, 58, 75, 24, dlg.wnd, win.IDNO, instance, nil)
	}

	dlg.layout(getDPI(dlg.wnd))
	centerWindow(dlg.wnd)
	win.ShowWindow(dlg.wnd, win.SW_NORMAL)
	if opts.maxValue < 0 {
		win.SendMessage(dlg.progCtl, win.PBM_SETMARQUEE, 1, 0)
	} else {
		win.SendMessage(dlg.progCtl, win.PBM_SETRANGE32, 0, uintptr(opts.maxValue))
	}
	once.Do(dlg.init.Done)

	if opts.ctx != nil && opts.ctx.Done() != nil {
		wait := make(chan struct{})
		defer close(wait)
		go func() {
			select {
			case <-opts.ctx.Done():
				win.SendMessage(dlg.wnd, win.WM_SYSCOMMAND, win.SC_CLOSE, 0)
			case <-wait:
			}
		}()
	}

	if err := win.MessageLoop(win.HWND(dlg.wnd)); err != nil {
		return err
	}
	if opts.ctx != nil && opts.ctx.Err() != nil {
		return opts.ctx.Err()
	}
	return dlg.err
}

func (d *progressDialog) layout(dpi dpi) {
	font := d.font.forDPI(dpi)
	win.SendMessage(d.textCtl, win.WM_SETFONT, font, 1)
	win.SendMessage(d.okBtn, win.WM_SETFONT, font, 1)
	win.SendMessage(d.cancelBtn, win.WM_SETFONT, font, 1)
	win.SendMessage(d.extraBtn, win.WM_SETFONT, font, 1)
	win.SetWindowPos(d.wnd, 0, 0, 0, dpi.scale(281), dpi.scale(133), win.SWP_NOMOVE|win.SWP_NOZORDER)
	win.SetWindowPos(d.textCtl, 0, dpi.scale(12), dpi.scale(10), dpi.scale(241), dpi.scale(16), win.SWP_NOZORDER)
	win.SetWindowPos(d.progCtl, 0, dpi.scale(12), dpi.scale(30), dpi.scale(241), dpi.scale(16), win.SWP_NOZORDER)

	pos := 178
	if d.cancelBtn != 0 {
		win.SetWindowPos(d.cancelBtn, 0, dpi.scale(pos), dpi.scale(58), dpi.scale(75), dpi.scale(24), win.SWP_NOZORDER)
		pos -= 83
	}
	if d.extraBtn != 0 {
		win.SetWindowPos(d.extraBtn, 0, dpi.scale(pos), dpi.scale(58), dpi.scale(75), dpi.scale(24), win.SWP_NOZORDER)
		pos -= 83
	}
	if d.okBtn != 0 {
		win.SetWindowPos(d.okBtn, 0, dpi.scale(pos), dpi.scale(58), dpi.scale(75), dpi.scale(24), win.SWP_NOZORDER)
		pos -= 83
	}

	if pos == 178 {
		win.SetWindowPos(d.wnd, 0, 0, 0, dpi.scale(281), dpi.scale(97), win.SWP_NOMOVE|win.SWP_NOZORDER)
	}
}

func progressProc(wnd win.HWND, msg uint32, wparam uintptr, lparam *unsafe.Pointer) uintptr {
	var dlg *progressDialog
	switch msg {
	case win.WM_NCCREATE:
		saveBackRef(uintptr(wnd), *lparam)
		dlg = (*progressDialog)(*lparam)
	case win.WM_NCDESTROY:
		deleteBackRef(uintptr(wnd))
	default:
		dlg = (*progressDialog)(loadBackRef(uintptr(wnd)))
	}

	switch msg {
	case win.WM_DESTROY:
		win.PostQuitMessage(0)

	case win.WM_CLOSE:
		dlg.err = ErrCanceled
		win.DestroyWindow(wnd)

	case win.WM_COMMAND:
		switch wparam {
		default:
			return 1
		case win.IDOK, win.IDYES:
			//
		case win.IDCANCEL:
			dlg.err = ErrCanceled
		case win.IDNO:
			dlg.err = ErrExtraButton
		}
		win.DestroyWindow(wnd)

	case win.WM_DPICHANGED:
		dlg.layout(dpi(uint32(wparam) >> 16))

	default:
		return win.DefWindowProc(wnd, msg, wparam, unsafe.Pointer(lparam))
	}

	return 0
}