package bar // import "hhvn.uk/hbspbar/bar"

import (
	"fmt"
	"sync"
	"image"
	"errors"

	"hhvn.uk/hbspbar/config"
	"hhvn.uk/hbspbar/common"
	"hhvn.uk/hbspbar/bspc"
	"hhvn.uk/hbspbar/drw"

	"github.com/jezek/xgb"
	"github.com/jezek/xgb/xproto"

	"github.com/jezek/xgbutil"
	"github.com/jezek/xgbutil/icccm"
	"github.com/jezek/xgbutil/ewmh"
	"github.com/jezek/xgbutil/xgraphics"
)


var bars     map[int]*bar
var stoploop chan bool

type bar struct {
	Mon     *bspc.Monitor
	w       xproto.Window
	i       *image.RGBA
	drawing sync.Mutex
}

func (b *bar) init() error {
	var err error

	go b.Mon.TopPadding(config.H)

	b.w, err = xproto.NewWindowId(drw.X)
	if err != nil {
		return common.Perror("xproto.NewWindowId", err)
	}

	geom := b.Mon.Rectangle
	xproto.CreateWindow(drw.X, drw.Screen.RootDepth, b.w, drw.Screen.Root,
		int16(geom.X), int16(geom.Y), uint16(geom.Width), uint16(config.H), 0,
		xproto.WindowClassInputOutput, drw.Screen.RootVisual,
		xproto.CwBackPixel|xproto.CwEventMask, []uint32{
			config.Bg,
			xproto.EventMaskStructureNotify })

	class := icccm.WmClass{"hbspbar", "hbspbar"}
	icccm.WmClassSet(drw.XU, b.w, &class)

	ewmh.WmWindowTypeSet(drw.XU, b.w, []string{"_NET_WM_WINDOW_TYPE_DOCK"})
	ewmh.WmStateSet(drw.XU, b.w, []string{"_NET_WM_STATE_STICKY", "_NET_WM_STATE_ABOVE"})

	err = xproto.MapWindowChecked(drw.X, b.w).Check()
	if err != nil {
		return common.Perror("xproto.MapWindow", err)
	}

	b.i = image.NewRGBA(b.rect())

	return nil
}

func (b *bar) rect() image.Rectangle {
	return image.Rect(0, 0, int(b.Mon.Rectangle.Width), int(config.H))
}

func (b *bar) drawText(x int, col uint32, text string) (int, error) {
	return drw.DrawText(b.i, x, col, text)
}

func (b *bar) drawRect(x, y, w, h int, c uint32, fill bool) {
	drw.DrawRect(b.i, x, y, w, h, c, fill)
}

func (b *bar) draw() {
	var bg     uint32
	var filled bool

	b.drawing.Lock()

	// Dimensions of drawing space
	cx := 0
	w  := int(b.Mon.Rectangle.Width)
	h  := int(config.H)


	// Draw background
	b.drawRect(0, 0, w, h, config.Bg, true)

	// Monitor
	montext := b.Mon.Name
	monw    := 6 + drw.TextWidth(montext) + 8

	if b.Mon.Focused {
		bg = config.Sel
	} else {
		bg = config.Bg2
	}

	b.drawRect(cx, 0, monw, h, bg, true)
	b.drawText(cx + 6, config.Fg, montext)
	cx += monw

	// Desktops
	boxw := 4
	ds   := len(b.Mon.Desktops)
	dw   := 4 + (4 + boxw + 2 + 3) * ds + 5

	for i := 0; i < ds; i++ {
		dw += drw.TextWidth(b.Mon.Desktops[i].Name)
	}

	cx += 4
	for i := 0; i < ds; i++ {
		d := b.Mon.Desktops[i]

		cx += 5

		if d.Focused {
			bg = config.Sel
		} else {
			bg = config.FgDark
		}

		filled = d.Root != nil

		b.drawRect(cx, 3, boxw, h - 7, bg, filled)
		cx += boxw + 2
		ax, _ := b.drawText(cx, config.Fg, d.Name)
		cx += ax + 2
	}
	cx += 5

	xgr := xgraphics.NewConvert(drw.XU, b.i)

	xgr.XSurfaceSet(b.w)
	xgr.XDraw()
	xgr.XPaint(b.w)

	b.drawing.Unlock()
}

func (b *bar) destroy() {
	if (b.Mon != nil) {
		b.Mon.TopPadding(0)
	}
	xproto.DestroyWindow(drw.X, b.w)
}

type eventwrap struct {
	Ev  xgb.Event
	Err error
}

// External interface
type handle struct {
	Create   chan int
	Destroy  chan int
	NewState chan *bspc.State
	Err      chan error
}

var Handle  handle

func init() {
	var state *bspc.State
	state = nil

	Handle.Create   = make(chan int)
	Handle.Destroy  = make(chan int)
	Handle.NewState = make(chan *bspc.State)
	Handle.Err      = make(chan error)

	events   := make(chan *eventwrap)
	stoploop  = make(chan bool, 1)
	xstop    := make(chan bool, 1)

	go func() { for {
		ev, err := drw.X.WaitForEvent()
		w := eventwrap{ev, err}

		select {
		case <- xstop:
			return
		default:
			events <- &w
		}
	}}()

	go func() {
		defer func() {
			xstop <- true
			close(Handle.Create)
			close(Handle.Destroy)
			close(Handle.NewState)
			close(Handle.Err)
		}()

		for {
			select {
			case e := <- events:
				if e.Ev == nil && e.Err == nil {
					Handle.Err <- fmt.Errorf("X connection clossed")
					return
				}

				if e.Err != nil {
					common.Perror("X.WaitForEvents", e.Err)
					continue
				}

				// switch e.Ev.(type) {
				// case xproto.DestroyNotifyEvent:
				// 	Handle.Err <- fmt.Errorf("Window destroyed")
				// 	return
				// default:
				// }
			case id := <- Handle.Destroy:
				bars[id].destroy()
				delete(bars, id)
			case id := <- Handle.Create:
				if state == nil {
					Handle.Err <- errors.New("attempted to create a bar with uninitialized state")
					return
				}
				if _, ok := bars[id]; ok { break }
				if err := create(drw.X, drw.XU, drw.Screen, state.GetMon(id)); err != nil {
					Handle.Err <- fmt.Errorf("Couldn't create window: %s\n", err)
					return
				}
			case state = <- Handle.NewState:
				for _, b := range bars {
					b.Mon = state.GetMon(b.Mon.ID)
					if b.Mon != nil {
						go b.draw()
					}
				}
			case <- stoploop:
				return
			}
		}
	}()
}

func create(x *xgb.Conn, xu *xgbutil.XUtil,
		scr *xproto.ScreenInfo, m *bspc.Monitor) (error) {
	var b bar

	b.Mon = m
	b.i   = nil

	if err := b.init(); err != nil {
		return err
	}

	go b.draw()

	if bars == nil {
		bars = make(map[int]*bar)
	}

	bars[b.Mon.ID] = &b
	return nil
}

func Cleanup() {
	for _, b := range bars {
		b.destroy()
	}
	stoploop <- true
}