package ui

import (
	"github.com/gdamore/tcell"
	"github.com/mattn/go-runewidth"
)

type Tabs struct {
	Tabs       []*Tab
	TabStrip   *TabStrip
	TabContent *TabContent
	Selected   int
	history    []int

	onInvalidateStrip   func(d Drawable)
	onInvalidateContent func(d Drawable)

	parent   *Tabs
	CloseTab func(index int)
}

type Tab struct {
	Content Drawable
	Name    string
	invalid bool
}

type TabStrip Tabs
type TabContent Tabs

func NewTabs() *Tabs {
	tabs := &Tabs{}
	tabs.TabStrip = (*TabStrip)(tabs)
	tabs.TabStrip.parent = tabs
	tabs.TabContent = (*TabContent)(tabs)
	tabs.TabContent.parent = tabs
	tabs.history = []int{}
	return tabs
}

func (tabs *Tabs) Add(content Drawable, name string) *Tab {
	tab := &Tab{
		Content: content,
		Name:    name,
	}
	tabs.Tabs = append(tabs.Tabs, tab)
	tabs.TabStrip.Invalidate()
	content.OnInvalidate(tabs.invalidateChild)
	return tab
}

func (tabs *Tabs) invalidateChild(d Drawable) {
	if tabs.Selected >= len(tabs.Tabs) {
		return
	}

	if tabs.Tabs[tabs.Selected].Content == d {
		if tabs.onInvalidateContent != nil {
			tabs.onInvalidateContent(tabs.TabContent)
		}
	}
}

func (tabs *Tabs) Remove(content Drawable) {
	indexToRemove := -1
	for i, tab := range tabs.Tabs {
		if tab.Content == content {
			tabs.Tabs = append(tabs.Tabs[:i], tabs.Tabs[i+1:]...)
			tabs.removeHistory(i)
			indexToRemove = i
			break
		}
	}
	if indexToRemove < 0 {
		return
	}
	// only pop the tab history if the closing tab is selected
	if indexToRemove == tabs.Selected {
		index, ok := tabs.popHistory()
		if ok {
			tabs.Select(index)
			interactive, ok := tabs.Tabs[tabs.Selected].Content.(Interactive)
			if ok {
				interactive.Focus(true)
			}
		}
	} else if indexToRemove < tabs.Selected {
		// selected tab is now one to the left of where it was
		tabs.Selected--
	}
	tabs.TabStrip.Invalidate()
}

func (tabs *Tabs) Replace(contentSrc Drawable, contentTarget Drawable, name string) {
	replaceTab := &Tab{
		Content: contentTarget,
		Name:    name,
	}
	for i, tab := range tabs.Tabs {
		if tab.Content == contentSrc {
			tabs.Tabs[i] = replaceTab
			tabs.Select(i)
			break
		}
	}
	tabs.TabStrip.Invalidate()
	contentTarget.OnInvalidate(tabs.invalidateChild)
}

func (tabs *Tabs) Select(index int) {
	if index >= len(tabs.Tabs) {
		index = len(tabs.Tabs) - 1
	}

	if tabs.Selected != index {
		// only push valid tabs onto the history
		if tabs.Selected < len(tabs.Tabs) {
			tabs.pushHistory(tabs.Selected)
		}
		tabs.Selected = index
		tabs.TabStrip.Invalidate()
		tabs.TabContent.Invalidate()
	}
}

func (tabs *Tabs) SelectPrevious() bool {
	index, ok := tabs.popHistory()
	if !ok {
		return false
	}
	tabs.Select(index)
	return true
}

func (tabs *Tabs) NextTab() {
	next := tabs.Selected + 1
	if next >= len(tabs.Tabs) {
		next = 0
	}
	tabs.Select(next)
}

func (tabs *Tabs) PrevTab() {
	next := tabs.Selected - 1
	if next < 0 {
		next = len(tabs.Tabs) - 1
	}
	tabs.Select(next)
}

func (tabs *Tabs) pushHistory(index int) {
	tabs.history = append(tabs.history, index)
}

func (tabs *Tabs) popHistory() (int, bool) {
	lastIdx := len(tabs.history) - 1
	if lastIdx < 0 {
		return 0, false
	}
	item := tabs.history[lastIdx]
	tabs.history = tabs.history[:lastIdx]
	return item, true
}

func (tabs *Tabs) removeHistory(index int) {
	newHist := make([]int, 0, len(tabs.history))
	for i, item := range tabs.history {
		if item == index {
			continue
		}
		if item > index {
			item = item - 1
		}
		// dedup
		if i > 0 && len(newHist) > 0 && item == newHist[len(newHist)-1] {
			continue
		}
		newHist = append(newHist, item)
	}
	tabs.history = newHist
}

// TODO: Color repository
func (strip *TabStrip) Draw(ctx *Context) {
	x := 0
	for i, tab := range strip.Tabs {
		style := tcell.StyleDefault.Reverse(true)
		if st<style>pre { line-height: 125%; }
td.linenos .normal { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
span.linenos { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
td.linenos .special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
span.linenos.special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
.highlight .hll { background-color: #ffffcc }
.highlight .c { color: #888888 } /* Comment */
.highlight .err { color: #a61717; background-color: #e3d2d2 } /* Error */
.highlight .k { color: #008800; font-weight: bold } /* Keyword */
.highlight .ch { color: #888888 } /* Comment.Hashbang */
.highlight .cm { color: #888888 } /* Comment.Multiline */
.highlight .cp { color: #cc0000; font-weight: bold } /* Comment.Preproc */
.highlight .cpf { color: #888888 } /* Comment.PreprocFile */
.highlight .c1 { color: #888888 } /* Comment.Single */
.highlight .cs { color: #cc0000; font-weight: bold; background-color: #fff0f0 } /* Comment.Special */
.highlight .gd { color: #000000; background-color: #ffdddd } /* Generic.Deleted */
.highlight .ge { font-style: italic } /* Generic.Emph */
.highlight .ges { font-weight: bold; font-style: italic } /* Generic.EmphStrong */
.highlight .gr { color: #aa0000 } /* Generic.Error */
.highlight .gh { color: #333333 } /* Generic.Heading */
.highlight .gi { color: #000000; background-color: #ddffdd } /* Generic.Inserted */
.highlight .go { color: #888888 } /* Generic.Output */
.highlight .gp { color: #555555 } /* Generic.Prompt */
.highlight .gs { font-weight: bold } /* Generic.Strong */
.highlight .gu { color: #666666 } /* Generic.Subheading */
.highlight .gt { color: #aa0000 } /* Generic.Traceback */
.highlight .kc { color: #008800; font-weight: bold } /* Keyword.Constant */
.highlight .kd { color: #008800; font-weight: bold } /* Keyword.Declaration */
.highlight .kn { color: #008800; font-weight: bold } /* Keyword.Namespace */
.highlight .kp { color: #008800 } /* Keyword.Pseudo */
.highlight .kr { color: #008800; font-weight: bold } /* Keyword.Reserved */
.highlight .kt { color: #888888; font-weight: bold } /* Keyword.Type */
.highlight .m { color: #0000DD; font-weight: bold } /* Literal.Number */
.highlight .s { color: #dd2200; background-color: #fff0f0 } /* Literal.String */
.highlight .na { color: #336699 } /* Name.Attribute */
.highlight .nb { color: #003388 } /* Name.Builtin */
.highlight .nc { color: #bb0066; font-weight: bold } /* Name.Class */
.highlight .no { color: #003366; font-weight: bold } /* Name.Constant */
.highlight .nd { color: #555555 } /* Name.Decorator */
.highlight .ne { color: #bb0066; font-weight: bold } /* Name.Exception */
.highlight .nf { color: #0066bb; font-weight: bold } /* Name.Function */
.highlight .nl { color: #336699; font-style: italic } /* Name.Label */
.highlight .nn { color: #bb0066; font-weight: bold } /* Name.Namespace */
.highlight .p