// 1 march 2014
package ui

import (
	"fmt"
	"unsafe"
	"sync"
)

// #cgo LDFLAGS: -lobjc -framework Foundation -framework AppKit
// #include "objc_darwin.h"
import "C"

type sysData struct {
	cSysData

	id	C.id
}

type classData struct {
	make		func(parentWindow C.id, alternate bool) C.id
	show		func(what C.id)
	hide			func(what C.id)
	settextsel		C.SEL
	textsel		C.SEL
	alttextsel		C.SEL
	append		func(id C.id, what string, alternate bool)
	insertBefore	func(id C.id, what string, before int, alternate bool)
	selIndex		func(id C.id) int
	selIndices		func(id C.id) []int
	selTexts		func(id C.id) []string
	delete		func(id C.id, index int)
	len			func(id C.id) int
}

var (
	_NSWindow = objc_getClass("NSWindow")
	_NSButton = objc_getClass("NSButton")
	_NSPopUpButton = objc_getClass("NSPopUpButton")
	_NSComboBox = objc_getClass("NSComboBox")
	_NSTextField = objc_getClass("NSTextField")
	_NSSecureTextField = objc_getClass("NSSecureTextField")
	_NSProgressIndicator = objc_getClass("NSProgressIndicator")

	_initWithContentRect = sel_getUid("initWithContentRect:styleMask:backing:defer:")
	_initWithFrame = sel_getUid("initWithFrame:")
	_makeKeyAndOrderFront = sel_getUid("makeKeyAndOrderFront:")
	_orderOut = sel_getUid("orderOut:")
	_setHidden = sel_getUid("setHidden:")
	_setTitle = sel_getUid("setTitle:")
	_setStringValue = sel_getUid("setStringValue:")
	_setFrame = sel_getUid("setFrame:")
	_state = sel_getUid("state")
	_title = sel_getUid("title")
	_stringValue = sel_getUid("stringValue")
	_frame = sel_getUid("frame")
	_setFrameDisplay = sel_getUid("setFrame:display:")
	_setBezelStyle = sel_getUid("setBezelStyle:")
	_setTarget = sel_getUid("setTarget:")
	_setAction = sel_getUid("setAction:")
	_contentView = sel_getUid("contentView")
	_addSubview = sel_getUid("addSubview:")
	_setButtonType = sel_getUid("setButtonType:")
	_initWithFramePullsDown = sel_getUid("initWithFrame:pullsDown:")
	_setUsesDataSource = sel_getUid("setUsesDataSource:")
	_addItemWithTitle = sel_getUid("addItemWithTitle:")
	_insertItemWithTitleAtIndex = sel_getUid("insertItemWithTitle:atIndex:")
	_removeItemAtIndex = sel_getUid("removeItemAtIndex:")
	_titleOfSelectedItem = sel_getUid("titleOfSelectedItem")
	_indexOfSelectedItem = sel_getUid("indexOfSelectedItem")
	_addItemWithObjectValue = sel_getUid("addItemWithObjectValue:")
	_insertItemWithObjectValueAtIndex = sel_getUid("insertItemWithObjectValue:atIndex:")
	_setEditable = sel_getUid("setEditable:")
	_setBordered = sel_getUid("setBordered:")
	_setDrawsBackground = sel_getUid("setDrawsBackground:")
	_setStyle = sel_getUid("setStyle:")
	_setControlSize = sel_getUid("setControlSize:")
	_setIndeterminate = sel_getUid("setIndeterminate:")
	_setDoubleValue = sel_getUid("setDoubleValue:")
	_numberOfItems = sel_getUid("numberOfItems")
)

func addControl(parentWindow C.id, control C.id) {
	windowView := C.objc_msgSend_noargs(parentWindow, _contentView)
	C.objc_msgSend_id(windowView, _addSubview, control)
}

func controlShow(what C.id) {
	C.objc_msgSend_bool(what, _setHidden, C.BOOL(C.NO))
}

func controlHide(what C.id) {
	C.objc_msgSend_bool(what, _setHidden, C.BOOL(C.YES))
}

var classTypes = [nctypes]*classData{
	c_window:		&classData{
		make:		func(parentWindow C.id, alternate bool) C.id {
			const (
				NSBorderlessWindowMask = 0
				NSTitledWindowMask = 1 << 0
				NSClosableWindowMask = 1 << 1
				NSMiniaturizableWindowMask = 1 << 2
				NSResizableWindowMask = 1 << 3
				NSTexturedBackgroundWindowMask = 1 << 8
			)

			// we have to specify a content rect to start; it will be overridden soon though
			win := objc_alloc(_NSWindow)
			win = objc_msgSend_rect_uint_uint_bool(win,
				_initWithContentRect,
				0, 0, 100, 100,
				NSTitledWindowMask | NSClosableWindowMask | NSMiniaturizableWindowMask | NSResizableWindowMask,
				2,					// NSBackingStoreBuffered - the only backing store method that Apple says we should use (the others are legacy)
				C.BOOL(C.YES))			// defer creation of device until we show the window
			objc_setDelegate(win, appDelegate)
			return win
		},
		show:		func(what C.id) {
			C.objc_msgSend_id(what, _makeKeyAndOrderFront, what)
		},
		hide:			func(what C.id) {
			C.objc_msgSend_id(what, _orderOut, what)
		},
		settextsel:		_setTitle,
		textsel:		_title,
	},
	c_button:			&classData{
		make:		func(parentWindow C.id, alternate bool) C.id {
			button := objc_alloc(_NSButton)
			// NSControl requires that we specify a frame; dummy frame for now
			button = objc_msgSend_rect(button, _initWithFrame,
				0, 0, 100, 100)
			objc_msgSend_uint(button, _setBezelStyle, 1)		// NSRoundedBezelStyle
			C.objc_msgSend_id(button, _setTarget, appDelegate)
			C.objc_msgSend_sel(button, _setAction, _buttonClicked)
			addControl(parentWindow, button)
			return button
		},
		show:		controlShow,
		hide:			controlHide,
		settextsel:		_setTitle,
		textsel:		_title,
	},
	c_checkbox:		&classData{
		make:		func(parentWindow C.id, alternate bool) C.id {
			checkbox := objc_alloc(_NSButton)
			checkbox = objc_msgSend_rect(checkbox, _initWithFrame,
				0, 0, 100, 100)
			objc_msgSend_uint(checkbox, _setButtonType, 3)		// NSSwitchButton
			addControl(parentWindow, checkbox)
			return checkbox
		},
		show:		controlShow,
		hide:			controlHide,
		settextsel:		_setTitle,
		textsel:		_title,
	},
	c_combobox:		&classData{
		make:		func(parentWindow C.id, alternate bool) C.id {
			var combobox C.id

			if alternate {
				combobox = objc_alloc(_NSComboBox)
				combobox = objc_msgSend_rect(combobox, _initWithFrame,
					0, 0, 100, 100)
				C.objc_msgSend_bool(combobox, _setUsesDataSource, C.BOOL(C.NO))
			} else {
				combobox = objc_alloc(_NSPopUpButton)
				combobox = objc_msgSend_rect_bool(combobox, _initWithFramePullsDown,
					0, 0, 100, 100,
					C.BOOL(C.NO))
			}
			addControl(parentWindow, combobox)
			return combobox
		},
		show:		controlShow,
		hide:			controlHide,
		// TODO setText
		textsel:		_titleOfSelectedItem,
		alttextsel:		_stringValue,
		append:		func(id C.id, what string, alternate bool) {
			str := toNSString(what)
			if alternate {
				C.objc_msgSend_id(id, _addItemWithObjectValue, str)
			} else {
				C.objc_msgSend_id(id, _addItemWithTitle, str)
			}
		},
		insertBefore:	func(id C.id, what string, before int, alternate bool) {
			str := toNSString(what)
			if alternate {
				C.objc_msgSend_id_int(id, _insertItemWithObjectValueAtIndex, str, C.intptr_t(before))
			} else {
				C.objc_msgSend_id_int(id, _insertItemWithTitleAtIndex, str, C.intptr_t(before))
			}
		},
		selIndex:		func(id C.id) int {
			return int(C.objc_msgSend_intret_noargs(id, _indexOfSelectedItem))
		},
		delete:		func(id C.id, index int) {
			C.objc_msgSend_int(id, _removeItemAtIndex, C.intptr_t(index))
		},
		len:			func(id C.id) int {
			return int(C.objc_msgSend_intret_noargs(id, _numberOfItems))
		},
	},
	c_lineedit:		&classData{
		make:		func(parentWindow C.id, alternate bool) C.id {
			var lineedit C.id

			if alternate {
				lineedit = objc_alloc(_NSSecureTextField)
			} else {
				lineedit = objc_alloc(_NSTextField)
			}
			lineedit = objc_msgSend_rect(lineedit, _initWithFrame,
				0, 0, 100, 100)
			addControl(parentWindow, lineedit)
			return lineedit
		},
		show:		controlShow,
		hide:			controlHide,
		settextsel:		_setStringValue,
		textsel:		_stringValue,
		alttextsel:		_stringValue,
	},
	c_label:			&classData{
		make:		func(parentWindow C.id, alternate bool) C.id {
			label := objc_alloc(_NSTextField)
			label = objc_msgSend_rect(label, _initWithFrame,
				0, 0, 100, 100)
			C.objc_msgSend_bool(label, _setEditable, C.BOOL(C.NO))
			C.objc_msgSend_bool(label, _setBordered, C.BOOL(C.NO))
			C.objc_msgSend_bool(label, _setDrawsBackground, C.BOOL(C.NO))
			// TODO others?
			addControl(parentWindow, label)
			return label
		},
		show:		controlShow,
		hide:			controlHide,
		settextsel:		_setStringValue,
		textsel:		_stringValue,
	},
	c_listbox:			&classData{
		make:		makeListbox,
		show:		controlShow,
		hide:			controlHide,
		append:		appendListbox,
		insertBefore:	insertListboxBefore,
		selIndices:	selectedListboxIndices,
		selTexts:		selectedListboxTexts,
		delete:		deleteListbox,
		len:			listboxLen,
	},
	c_progressbar:		&classData{
		make:		func(parentWindow C.id, alternate bool) C.id {
			pbar := objc_alloc(_NSProgressIndicator)
			pbar = objc_msgSend_rect(pbar, _initWithFrame,
				0, 0, 100, 100)
			// TODO really int?
			C.objc_msgSend_int(pbar, _setStyle, 0)			// NSProgressIndicatorBarStyle
			objc_msgSend_uint(pbar, _setControlSize, 0)		// NSRegularControlSize
			C.objc_msgSend_bool(pbar, _setIndeterminate, C.BOOL(C.NO))
			addControl(parentWindow, pbar)
			return pbar
		},
		show:		controlShow,
		hide:			controlHide,
	},
}

// I need to access sysData from appDelegate, but appDelegate doesn't store any data. So, this.
var (
	sysdatas = make(map[C.id]*sysData)
	sysdatalock sync.Mutex
)

func addSysData(key C.id, value *sysData) {
	sysdatalock.Lock()
	sysdatas[key] = value
	sysdatalock.Unlock()
}

func getSysData(key C.id) *sysData {
	sysdatalock.Lock()
	defer sysdatalock.Unlock()

	v, ok := sysdatas[key]
	if !ok {
		panic(fmt.Errorf("internal error: getSysData(%v) unknown", key))
	}
	return v
}

func (s *sysData) make(initText string, window *sysData) error {
	var parentWindow C.id

	ct := classTypes[s.ctype]
	if window != nil {
		parentWindow = window.id
	}
	ret := make(chan C.id)
	defer close(ret)
	uitask <- func() {
		ret <- ct.make(parentWindow, s.alternate)
	}
	s.id = <-ret
	err := s.setText(initText)
	if err != nil {
		return fmt.Errorf("error setting initial text of new window/control: %v", err)
	}
	addSysData(s.id, s)
	return nil
}

// used for Windows; nothing special needed elsewhere
func (s *sysData) firstShow() error {
	s.show()
	return nil
}

func (s *sysData) show() {
	ret := make(chan struct{})
	defer close(ret)
	uitask <- func() {
		classTypes[s.ctype].show(s.id)
		ret <- struct{}{}
	}
	<-ret
}

func (s *sysData) hide() {
	ret := make(chan struct{})
	defer close(ret)
	uitask <- func() {
		classTypes[s.ctype].hide(s.id)
		ret <- struct{}{}
	}
	<-ret
}

func (s *sysData) setText(text string) error {
	var zeroSel C.SEL

	if classTypes[s.ctype].settextsel == zeroSel {		// does not have concept of text
		return nil
	}
	ret := make(chan struct{})
	defer close(ret)
	uitask <- func() {
		C.objc_msgSend_id(s.id, classTypes[s.ctype].settextsel, toNSString(text))
		ret <- struct{}{}
	}
	<-ret
	return nil
}

func (s *sysData) setRect(x int, y int, width int, height int, winheight int) error {
	// winheight - y because (0,0) is the bottom-left corner of the window and not the top-left corner
	// (winheight - y) - height because (x, y) is the bottom-left corner of the control and not the top-left
	objc_msgSend_rect(s.id, _setFrame, x, (winheight - y) - height, width, height)
	return nil
}

func (s *sysData) isChecked() bool {
	const (
		NSOnState = 1
	)

	ret := make(chan bool)
	defer close(ret)
	uitask <- func() {
		k := C.objc_msgSend_noargs(s.id, _state)
		ret <- uintptr(unsafe.Pointer(k)) == NSOnState
	}
	return <-ret
}

func (s *sysData) text() string {
	sel := classTypes[s.ctype].textsel
	if s.alternate {
		sel = classTypes[s.ctype].alttextsel
	}
	ret := make(chan string)
	defer close(ret)
	uitask <- func() {
		str := C.objc_msgSend_noargs(s.id, sel)
		ret <- fromNSString(str)
	}
	return <-ret
}

func (s *sysData) append(what string) {
	ret := make(chan struct{})
	defer close(ret)
	uitask <- func() {
		classTypes[s.ctype].append(s.id, what, s.alternate)
		ret <- struct{}{}
	}
	<-ret
}

func (s *sysData) insertBefore(what string, before int) {
	ret := make(chan struct{})
	defer close(ret)
	uitask <- func() {
		classTypes[s.ctype].insertBefore(s.id, what, before, s.alternate)
		ret <- struct{}{}
	}
	<-ret
}

func (s *sysData) selectedIndex() int {
	ret := make(chan int)
	defer close(ret)
	uitask <- func() {
		ret <- classTypes[s.ctype].selIndex(s.id)
	}
	return <-ret
}

func (s *sysData) selectedIndices() []int {
	ret := make(chan []int)
	defer close(ret)
	uitask <- func() {
		ret <- classTypes[s.ctype].selIndices(s.id)
	}
	return <-ret
}

func (s *sysData) selectedTexts() []string {
	ret := make(chan []string)
	defer close(ret)
	uitask <- func() {
		ret <- classTypes[s.ctype].selTexts(s.id)
	}
	return <-ret
}

func (s *sysData) setWindowSize(width int, height int) error {
	ret := make(chan struct{})
	defer close(ret)
	uitask <- func() {
		// we need to get the top left point
		r := C.objc_msgSend_stret_rect_noargs(s.id, _frame)
		objc_msgSend_rect_bool(s.id, _setFrameDisplay,
			int(r.x), int(r.y), width, height,
			C.BOOL(C.YES))		// TODO set to NO to prevent subviews from being redrawn before they are resized?
		ret <- struct{}{}
	}
	<-ret
	return nil
}

func (s *sysData) delete(index int) error {
	ret := make(chan struct{})
	defer close(ret)
	uitask <- func() {
		classTypes[s.ctype].delete(s.id, index)
		ret <- struct{}{}
	}
	<-ret
	return nil
}

func (s *sysData) setProgress(percent int) {
	ret := make(chan struct{})
	defer close(ret)
	uitask <- func() {
		C.objc_msgSend_double(s.id, _setDoubleValue, C.double(percent))
		ret <- struct{}{}
	}
	<-ret
}

func (s *sysData) len() int {
	ret := make(chan int)
	defer close(ret)
	uitask <- func() {
		ret <- classTypes[s.ctype].len(s.id)
	}
	return <-ret
}