// +build darwin linux

package main

import (
	"image"
	"image/color"
	"io/ioutil"
	"os"
	"path"
	"strings"
	"sync"
	"time"

	"gioui.org/ui"
	"gioui.org/ui/app"
	"gioui.org/ui/f32"
	"gioui.org/ui/gesture"
	"gioui.org/ui/input"
	"gioui.org/ui/key"
	"gioui.org/ui/layout"
	"gioui.org/ui/measure"
	"gioui.org/ui/paint"
	"gioui.org/ui/pointer"
	"gioui.org/ui/text"

	"github.com/fsnotify/fsnotify"
	"gopkg.in/yaml.v2"

	"git.wow.st/gmp/passgo"
)

type conf struct {
	StoreDir string
}

func main() {
	var fd *os.File
	confFile := path.Join(confDir, "config.yml")
	if _, err := os.Stat(confFile); os.IsNotExist(err) {
		fd, err = os.Create(confFile)
		if err != nil {
			log(Fatal, "Cannot create configuration file: ", err)
		}
	}

	confbytes, err := ioutil.ReadFile(confFile)
	if err != nil {
		log(Fatal, "Cannot read configuration file: ", err)
	}
	if err = yaml.UnmarshalStrict(confbytes, &Config); err != nil {
		log(Fatal, "Cannot parse configuration file: ", err)
	}
	store.Dir = Config.StoreDir
	log(Info, " StoreDir = ", store.Dir)
	err = passgo.GetStore(&store)
	if err != nil {
		log(Fatal, err)
	}

	if fd != nil { // we still have an empty conf file open:
		Config.StoreDir = store.Dir
		saveConf(fd)
	}

	reload = make(chan struct{})
	updated = make(chan struct{})

	go Updater()
	log(Info, "Staring event loop")
	go eventLoop()
	app.Main()
	log(Info, "Event loop returned")
}

var (
	Config   conf
	l        []passgo.Pass
	mux      sync.Mutex
	store    passgo.Store
	reload   chan struct{}
	updated  chan struct{}
	black    = color.RGBA{A: 0xff, R: 0, G: 0, B: 0}
	white    = color.RGBA{A: 0xff, R: 0xff, G: 0xff, B: 0xff}
	gray     = color.RGBA{A: 0xff, R: 0xf0, G: 0xf0, B: 0xf0}
	darkgray = color.RGBA{A: 0xff, R: 0xa0, G: 0xa0, B: 0xa0}
)

func Updater() {
	update := func() {
		ltmp, err := store.List()
		if err != nil {
			log(Info, err)
		}
		mux.Lock()
		l = ltmp
		mux.Unlock()
		updated <- struct{}{}
	}
	update()

	watcher, err := fsnotify.NewWatcher()
	if err != nil {
		log(Fatal, err)
	}
	watcher.Add(store.Dir)
	for {
		select {
		case <-reload:
			update()
		case <-watcher.Events:
			update()
		case e := <-watcher.Errors:
			log(Info, "Watcher error: ", e)
		}
	}
}

func saveConf(fds ...*os.File) {
	var fd *os.File
	var err error
	if len(fds) > 0 && fds[0] != nil {
		fd = fds[0]
	} else {
		fd, err = os.Create(path.Join(confDir, "config.yml"))
		if err != nil {
			log(Fatal, "Cannot open config file: ", err)
		}
	}

	confbytes, err := yaml.Marshal(Config)
	if err != nil {
		log(Fatal, "Cannot save configuration: ", err)
	}
	_, err = fd.Write(confbytes)
	if err != nil {
		log(Fatal, "Cannot write to configuration: ", err)
	}
}

type Overlay struct {
	Face       text.Face
	Text       string
	Click      gesture.Click
	Color      color.RGBA
	Background color.RGBA
	Alignment  text.Alignment
}

func (b *Overlay) Layout(c ui.Config, ops *ui.Ops, cs layout.Constraints) layout.Dimensions {
	ins := layout.UniformInset(ui.Dp(1))
	cs = ins.Begin(c, ops, cs)
	var dims layout.Dimensions
	st := layout.Stack{}
	st.Init(ops, cs)
	{
		cs = st.Rigid()
		l := text.Label{
			Face:      b.Face,
			Text:      b.Text,
			Alignment: b.Alignment,
		}
		ins := layout.UniformInset(ui.Dp(4))
		l.Material.Record(ops)
		paint.ColorOp{Color: b.Color}.Add(ops)
		l.Material.Stop()
		dims = ins.End(l.Layout(ops, ins.Begin(c, ops, cs)))
		pointer.RectAreaOp{image.Rect(0, 0, dims.Size.X, dims.Size.Y)}.Add(ops)
	}
	c2 := st.End(dims)
	c1 := st.End(layoutRRect(b.Background, c, ops, st.Expand()))
	dims = st.Layout(c1, c2)
	return ins.End(dims)
}

type Button struct {
	Face       text.Face
	Label      string
	Click      gesture.Click
	Color      color.RGBA
	Background color.RGBA
	Alignment  text.Alignment
	clicked    bool
}

func layoutRRect(col color.RGBA, c ui.Config, ops *ui.Ops, cs layout.Constraints) layout.Dimensions {
	r := float32(c.Px(ui.Dp(4)))
	sz := image.Point{X: cs.Width.Min, Y: cs.Height.Min}
	w, h := float32(sz.X), float32(sz.Y)
	rrect(ops, w, h, r, r, r, r)
	paint.ColorOp{Color: col}.Add(ops)
	paint.PaintOp{Rect: f32.Rectangle{Max: f32.Point{X: w, Y: h}}}.Add(ops)
	return layout.Dimensions{Size: sz}
}

// https://pomax.github.io/bezierinfo/#circles_cubic.
func rrect(ops *ui.Ops, width, height, se, sw, nw, ne float32) {
	w, h := float32(width), float32(height)
	const c = 0.55228475 // 4*(sqrt(2)-1)/3
	var b paint.PathBuilder
	b.Init(ops)
	b.Move(f32.Point{X: w, Y: h - se})
	b.Cube(f32.Point{X: 0, Y: se * c}, f32.Point{X: -se + se*c, Y: se}, f32.Point{X: -se, Y: se}) // SE
	b.Line(f32.Point{X: sw - w + se, Y: 0})
	b.Cube(f32.Point{X: -sw * c, Y: 0}, f32.Point{X: -sw, Y: -sw + sw*c}, f32.Point{X: -sw, Y: -sw}) // SW
	b.Line(f32.Point{X: 0, Y: nw - h + sw})
	b.Cube(f32.Point{X: 0, Y: -nw * c}, f32.Point{X: nw - nw*c, Y: -nw}, f32.Point{X: nw, Y: -nw}) // NW
	b.Line(f32.Point{X: w - ne - nw, Y: 0})
	b.Cube(f32.Point{X: ne * c, Y: 0}, f32.Point{X: ne, Y: ne - ne*c}, f32.Point{X: ne, Y: ne}) // NE
	b.End()
}

func (b *Button) Layout(c ui.Config, q input.Queue, ops *ui.Ops, cs layout.Constraints) layout.Dimensions {
	b.clicked = false
	for ev, ok := b.Click.Next(q); ok; ev, ok = b.Click.Next(q) {
		if ev.Type == gesture.TypeClick {
			b.clicked = true
		}
	}
	ins := layout.UniformInset(ui.Dp(1))
	cs = ins.Begin(c, ops, cs)
	var dims layout.Dimensions
	st := layout.Stack{}
	st.Init(ops, cs)
	{
		cs = st.Rigid()
		l := text.Label{
			Face:      b.Face,
			Text:      b.Label,
			Alignment: b.Alignment,
		}
		ins := layout.UniformInset(ui.Dp(4))
		paint.ColorOp{Color: b.Color}.Add(ops)
		dims = ins.End(l.Layout(ops, ins.Begin(c, ops, cs)))
		pointer.RectAreaOp{image.Rect(0, 0, dims.Size.X, dims.Size.Y)}.Add(ops)
		b.Click.Add(ops)
	}
	c2 := st.End(dims)
	c1 := st.End(layoutRRect(b.Background, c, ops, st.Expand()))
	dims = st.Layout(c1, c2)
	return ins.End(dims)
}

func (b *Button) Clicked() bool {
	return b.clicked
}

func eventLoop() {
	w := app.NewWindow(app.WithWidth(ui.Dp(250)))
	q := w.Queue()
	var c ui.Config
	ops := new(ui.Ops)
	var dims layout.Dimensions
	var cs layout.Constraints
	var margincs layout.Constraints
	var faces measure.Faces
	var c1 layout.FlexChild // flex child for title bar
	face := faces.For(regular, ui.Sp(16))

	margin := layout.UniformInset(ui.Dp(10))

	title := &text.Label{Face: face, Text: "passgo"}
	dotsbtn := &Button{
		Face:       face,
		Label:      "\xe2\x8b\xae",
		Alignment:  text.End,
		Color:      black,
		Background: gray,
	}

	titleflex := &layout.Flex{Axis: layout.Horizontal}

	flex := &layout.Flex{Axis: layout.Vertical}
	passInput := &text.Editor{Face: face, SingleLine: true}
	passInput.SetText("passphrase")
	passSubmit := &Button{Face: face, Label: "submit", Color: black}
	lst := &layout.List{Axis: layout.Vertical}
	passBtns := make([]*Button, 0)
	_ = passInput
	_ = passSubmit
	pathnames := make([]string, 0)
	copied := &Overlay{Face: face, Text: "copied to clipboard",
		Color:      black,
		Background: darkgray,
		Alignment:  text.Middle,
	}
	var copiedWhen time.Time

	updateBtns := func() {
		passBtns = passBtns[:0]
		pathnames = pathnames[:0]
		mux.Lock()
		for _, x := range l {
			_, n := path.Split(x.Pathname)
			s := strings.Repeat("  /", x.Level)
			z := ""
			if x.Dir {
				z = "/"
			}
			passBtns = append(passBtns, &Button{
				Face:       face,
				Label:      strings.Join([]string{s, n, z}, ""),
				Background: gray,
			})
			pathnames = append(pathnames, x.Pathname)
		}
		mux.Unlock()
	}
	updateBtns()

	confBtn := &Button{
		Face:       face,
		Label:      "configure",
		Alignment:  text.Middle,
		Color:      black,
		Background: gray,
	}

	storeDirLabel := &text.Label{Face: face, Text: "Store directory"}
	storeDirEd := &text.Editor{Face: face, SingleLine: true}
	storeDirEd.SetText(store.Dir)
	saveBtn := &Button{
		Face:       face,
		Label:      "save",
		Alignment:  text.End,
		Color:      black,
		Background: gray,
	}
	backBtn := &Button{
		Face:       face,
		Label:      "back",
		Alignment:  text.End,
		Color:      black,
		Background: gray,
	}

	anim := &time.Ticker{}
	animating := false
	animOn := func() {
		anim = time.NewTicker(time.Second / 120)
		animating = true
		w.Invalidate()
	}
	animOff := func() {
		anim.Stop()
		animating = false
	}

	var listPage, confPage, page func()
	_ = confPage

	listPage = func() {
		cs = flex.Flexible(1.0)
		mux.Lock()
		if lst.Dragging() {
			key.HideInputOp{}.Add(ops)
		}
		var c2 layout.FlexChild
		if len(passBtns) == 0 {
			c2 = flex.End(confBtn.Layout(c, q, ops, cs))
			if confBtn.Clicked() {
				log(Info, "Configure")
				w.Invalidate()
				page = confPage
			}
		} else {
			for lst.Init(c, q, ops, cs, len(passBtns)); lst.More(); lst.Next() {
				btn := passBtns[lst.Index()]
				dims = btn.Layout(c, q, ops, lst.Constraints())
				lst.End(dims)
				if btn.Clicked() {
					log(Info, "Clicked ", btn.Label)
					// don't block UI thread on decryption attempt
					go func(name string) {
						//p,err := store.Decrypt(name, prompt)
						p, err := store.Decrypt(name)
						if err == nil {
							passgo.Clip(p)
							copiedWhen = time.Now()
							animOn()
						} else {
							log(Info, "Can't decrypt ", name)
							log(Info, err)
						}
					}(pathnames[lst.Index()])
				}
			}
			c2 = flex.End(lst.Layout())
		}
		mux.Unlock()
		if dotsbtn.Clicked() {
			log(Info, "Configure")
			w.Invalidate()
			page = confPage
		}
		flex.Layout(c1, c2)
		x := time.Since(copiedWhen).Seconds()
		start, end := 1.5, 1.75
		switch {
		case x > start && x < end:
			fade := (end - x) / (end - start)
			copied.Color.R = uint8(float64(black.R) * fade)
			copied.Color.G = uint8(float64(black.G) * fade)
			copied.Color.B = uint8(float64(black.B) * fade)
			copied.Color.A = uint8(float64(black.A) * fade)
			copied.Background.R = uint8(float64(darkgray.R) * fade)
			copied.Background.G = uint8(float64(darkgray.G) * fade)
			copied.Background.B = uint8(float64(darkgray.B) * fade)
			copied.Background.A = uint8(float64(darkgray.A) * fade)
			fallthrough
		case x <= start:
			cs = margincs
			al := layout.Align{Alignment: layout.SE}
			cs = al.Begin(ops, cs)
			cs.Width.Min = cs.Width.Max
			dims = al.End(copied.Layout(c, ops, cs))
		case animating:
			copied.Color = black
			copied.Background = darkgray
			animOff()
		}
	}

	confPage = func() {
		cs = flex.Rigid()
		c2 := flex.End(storeDirLabel.Layout(ops, cs))
		cs = flex.Rigid()
		c3 := flex.End(storeDirEd.Layout(c, q, ops, cs))
		cs = flex.Rigid()
		al := &layout.Align{Alignment: layout.E}
		cs = al.Begin(ops, cs)
		btnflx := &layout.Flex{Axis: layout.Horizontal}
		btnflx.Init(ops, cs)
		cs = btnflx.Rigid()
		bc1 := btnflx.End(backBtn.Layout(c, q, ops, cs))
		cs = btnflx.Rigid()
		bc2 := btnflx.End(saveBtn.Layout(c, q, ops, cs))
		dims = btnflx.Layout(bc1, bc2)
		c4 := flex.End(al.End(dims))
		flex.Layout(c1, c2, c3, c4)
		if backBtn.Clicked() {
			log(Info, "Back")
			storeDirEd.SetText(store.Dir)
			w.Invalidate()
			page = listPage
		}
		if saveBtn.Clicked() {
			log(Info, "Save")
			go func() { // do not block UI thread
				store.Dir = storeDirEd.Text()
				passgo.GetStore(&store)
				Config.StoreDir = store.Dir
				saveConf()
				reload <- struct{}{}
			}()
			w.Invalidate()
			page = listPage
		}
	}

	page = listPage

	for {
		select {
		case <-updated:
			log(Info, "UPDATE")
			updateBtns()
			w.Invalidate()
		case <-anim.C:
			w.Invalidate()
		case e := <-w.Events():
			switch e := e.(type) {
			case app.DestroyEvent:
				return
			case app.UpdateEvent:
				c = &e.Config
				ops.Reset()
				faces.Reset(c)
				cs = layout.RigidConstraints(e.Size)
				cs = margin.Begin(c, ops, cs)
				margincs = cs
				flex.Init(ops, cs)
				cs = flex.Rigid()
				titleflex.Init(ops, cs)
				cs = titleflex.Rigid()
				ct2 := titleflex.End(dotsbtn.Layout(c, q, ops, cs))
				cs = titleflex.Flexible(1.0)
				cs.Width.Min = cs.Width.Max
				ct1 := titleflex.End(title.Layout(ops, cs))
				c1 = flex.End(titleflex.Layout(ct1, ct2))

				page()

				margin.End(dims)
				w.Update(ops)
			}
		}
	}
}