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

import (
	"fmt"
	"image"
	"errors"
	"image/color"

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


var bars     map[int]*bar

type drawinfo struct {
	State  *bspc.State
	Blocks *status.Blocks
}

type bar struct {
	id      int
	w       *drw.Window
	i       *image.RGBA
	redraw  chan drawinfo
}

func (b *bar) init(state *bspc.State) error {
	mon, err := b.getmon(state)
	if err != nil { return err }

	go mon.TopPadding(config.H)

	geom := mon.Rectangle

	b.w, err = drw.WindowCreate(geom.X, geom.Y, geom.Width, config.H)
	if err != nil { return err }

	rect := image.Rect(0, 0, int(mon.Rectangle.Width), int(config.H))
	b.i = image.NewRGBA(rect)

	b.redraw = make(chan drawinfo, 20)

	go func(){
		for d := range b.redraw {
			// Gobble up excess redraws
		gobble: for {
				select {
				case d = <- b.redraw:
				default: break gobble
				}
			}

			b.draw(d)
		}
	}()

	return nil
}

func (b bar) getmon(state *bspc.State) (*bspc.Monitor, error) {
	return state.GetMon(b.id)
}

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

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

func (b bar) draw(d drawinfo) {
	var bg     color.Color
	var filled bool

	state  := d.State
	blocks := d.Blocks

	mon, err := b.getmon(state)
	if err != nil {
		return
	}

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


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

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

	if mon.Focused {
		bg = config.Sel
	} else {
		bg = config.UnselMon
	}

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

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

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

	cx += 4
	for i := 0; i < ds; i++ {
		d := 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 = int(mon.Rectangle.Width) - 6
	for i := blocks.Len() - 1; i >= 0; i -= 1 {
		s, ok := blocks.Get(i)
		if ok {
			cx -= s.W
			cx -= config.StatusPad
		}
	}
	cx += config.StatusPad
	cx -= 6

	b.drawRect(cx, 0, int(mon.Rectangle.Width) - cx, int(config.H),
		config.Status, true)

	cx = int(mon.Rectangle.Width) - 6
	for i := blocks.Len() - 1; i >= 0; i -= 1 {
		s, ok := blocks.Get(i)
		if ok {
			cx -= s.W

			drw.AddImg(b.i, cx, s.W, s.I)

			cx -= config.StatusPad
		}
	}

	b.w.Paint(b.i)
}

func (b *bar) destroy(state *bspc.State) {
	close(b.redraw)
	mon, _ := b.getmon(state)
	if (mon != nil) {
		mon.TopPadding(0)
	}
}

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

// Store the state for when bar.Cleanup() is called
// This is a bit hacky but I don't really see any alternative
var finalstate *bspc.State = nil

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

	go func() {
		defer func() {
			close(Create)
			close(Destroy)
			close(NewState)
			close(Err)
		}()

		for {
			select {
			case e := <- drw.Events:
				if e.Ev == nil && e.Err == nil {
					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:
				// 	Err <- fmt.Errorf("Window destroyed")
				// 	return
				// default:
				// }
			case id := <- Destroy:
				bars[id].destroy(state)
				delete(bars, id)
			case id := <- Create:
				if state == nil {
					Err <- errors.New("attempted to create a bar with uninitialized state")
					return
				}
				if _, ok := bars[id]; ok { break }
				if err := create(state, id); err != nil {
					Err <- fmt.Errorf("Couldn't create window: %s\n", err)
					return
				}
			case blocks = <- status.NewBlocks:
				for _, b := range bars {
					b.redraw <- drawinfo{state, blocks}
				}
			case state = <- NewState:
				finalstate = state
				for _, b := range bars {
					b.redraw <- drawinfo{state, blocks}
				}
			}
		}
	}()
}

func create(state *bspc.State, id int) (error) {
	var b bar

	b.id = id
	b.i  = nil

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

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

	bars[b.id] = &b
	return nil
}

func Cleanup() {
	if finalstate != nil {
		for _, b := range bars {
			b.destroy(finalstate)
		}
	}
}