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

import (
	"fmt"
	"sync"
	"errors"
	"container/list"

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

	"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"

	"github.com/BurntSushi/freetype-go/freetype/truetype"
)

var conf = struct {
	H        uint
	Bg       uint32
	Bg2      uint32
	Bg3      uint32
	Fg       uint32
	FgDark   uint32
	Sel      uint32
	Urg      uint32
	Font     string
	FontSize float64
	FontYPad int
} { 	17,
	0xff050a10,
	0xff0c1726,
	0xff14283c,
	0xffeeeeee,
	0xff444444,
	0xff1b364b,
	0xff90222b,
	"/usr/share/fonts/TTF/DejaVuSansMono.ttf",
	11.0, 1 }

var bars     *list.List
var font     *truetype.Font
var stoploop chan bool

type bar struct {
	X       *xgb.Conn
	Xu      *xgbutil.XUtil
	Scr     *xproto.ScreenInfo
	Mon     *bspc.Monitor
	w       xproto.Window
	i       *xgraphics.Image
	tw, th  int
	tbpad   int
	drawing sync.Mutex
}

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

	go b.Mon.TopPadding(conf.H)

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

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

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

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

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

	b.drawReInit()
	b.tw, b.th, _ = b.i.Text(0, 0, int2BGRA(conf.Fg), conf.FontSize, font, "X")
	b.tbpad = (int(conf.H) - b.th) / 2

	return nil
}

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

	b.drawing.Lock()
	b.drawReInit()

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


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

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

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

	b.drawRect(cx, 0, monw, h, bg, true)
	b.drawText(cx + 6, conf.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 += b.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 = conf.Sel
		} else {
			bg = conf.FgDark
		}

		filled = d.Root != nil

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

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

	b.drawing.Unlock()
}

func (b *bar) destroy() {
	b.Mon.TopPadding(0)
	xproto.DestroyWindow(b.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 InitErr error
var Handle  handle

func init() {
	InitErr = nil

	bars = list.New()

	x, err := xgb.NewConn()
	if err != nil {
		InitErr = err
		return
	}

	xu, err := xgbutil.NewConnXgb(x)
	if err != nil {
		InitErr = err
		return
	}

	font, err = getFont(conf.Font)
	if err != nil {
		InitErr = err
		return
	}

	setup  := xproto.Setup(x)
	screen := setup.DefaultScreen(x)

	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 := 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", err)
					continue
				}

				// switch e.Ev.(type) {
				// case xproto.DestroyNotifyEvent:
				// 	Handle.Err <- fmt.Errorf("Window destroyed")
				// 	return
				// default:
				// }
			case id := <- Handle.Destroy:
				destroy(id)
			case id := <- Handle.Create:
				if state == nil {
					Handle.Err <- errors.New("attempted to create a bar with uninitialized state")
					return
				}
				if getbar(id) != nil { break }
				if err := create(x, xu, screen, state.GetMon(id)); err != nil {
					Handle.Err <- fmt.Errorf("Couldn't create window: %s\n", err)
					return
				}
			case state = <- Handle.NewState:
				fmt.Println(state)
				for e := bars.Front(); e != nil; e = e.Next() {
					v := e.Value.(*bar)
					v.Mon = state.GetMon(v.Mon.ID)
					go v.draw()
				}
			case <- stoploop:
				return
			}
		}
	}()
}

func getbar(monid int) (*bar) {
	for e := bars.Front(); e != nil; e = e.Next() {
		v := e.Value.(*bar)

		if v.Mon.ID == monid { return v }
	}

	return nil
}

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

	b.X   = x
	b.Xu  = xu
	b.Scr = scr
	b.Mon = m
	b.i   = nil

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

	go b.draw()

	bars.PushBack(&b)
	return nil
}

func destroy(monid int) (bool) {
	var next *list.Element

	for e := bars.Front(); e != nil; e = next {
		next = e.Next()
		v   := e.Value.(*bar)

		/* A monid of -1 means that we're doing
		   the bar.Cleanup schermoodle today */
		if monid == -1 || monid > 0 && v.Mon.ID == monid {
			v.destroy()
			bars.Remove(e)
			if monid != -1 { return true }
		}
	}

	if monid == -1 { return true }
	return false
}

func Cleanup() {
	destroy(-1)
	stoploop <- true
}