package pgenr

import (
	"bytes"
	"golang.org/x/net/html/atom"
	"html"
	"sync"
)

const (
	TextThemeSuccess = "success"
	TextThemeDanger  = "danger"
)

var (
	bufferPool sync.Pool
)

func getBuffer() *bytes.Buffer {
	if v := bufferPool.Get(); v == nil {
		return new(bytes.Buffer)
	} else {
		return v.(*bytes.Buffer)
	}
}

func releaseBuffer(sb *bytes.Buffer) {
	sb.Reset()
	bufferPool.Put(sb)
}

type (
	Element interface {
		Html() string
	}

	Style map[string]string

	TextOption func(t *Text)

	ButtonOption func(btn *Button)

	Text struct {
		Tag     atom.Atom
		Content string
		Theme   string
		Color   string
		Style   Style
	}

	Button struct {
		Url   string
		Text  string
		Color string
		Style Style
	}

	Entry struct {
		Title Element
		Items map[string]Element
	}

	Action struct {
		Instructions Element
		Button       *Button
		InviteCode   string
	}

	Table struct {
		Title  Element
		Header []Element
		Body   [][]Element
	}

	Page struct {
		Title     string
		Head      string
		Intros    []Element
		Entries   []*Entry
		Actions   []*Action
		Tables    []*Table
		Outros    []Element
		Copyright string
	}
)

func (s Style) Css(name string, value string) {
	s[name] = value
}

func (s Style) String() string {
	br := getBuffer()
	defer releaseBuffer(br)
	for k, v := range s {
		br.WriteString(k)
		br.WriteString(":")
		br.WriteString(v)
		br.WriteString(";")
	}
	return br.String()
}

func (a *Action) Html() string {
	return a.String()
}

func (a *Action) String() string {
	br := getBuffer()
	defer releaseBuffer(br)
	if a.Instructions != nil {
		br.WriteString(a.Instructions.Html())
	}
	br.WriteString("<div class='action-block'>")
	if a.InviteCode != "" {
		br.WriteString("<span class='invite-code'>")
		br.WriteString(html.EscapeString(a.InviteCode))
		br.WriteString("</span>")
	}
	if a.Button != nil {
		br.WriteString(a.Button.String())
	}
	br.WriteString("</div>")
	return br.String()
}

func (e *Entry) Html() string {
	return e.String()
}

func (e *Entry) String() string {
	br := getBuffer()
	defer releaseBuffer(br)
	br.WriteString("<div class='grid'>")
	if e.Title != nil {
		br.WriteString(e.Title.Html())
	}
	for k, v := range e.Items {
		br.WriteString("<div class='row'>")
		br.WriteString("<div class='preview-label'>")
		br.WriteString(k)
		br.WriteString("</div>")
		br.WriteString("<div class='preview-value'>")
		br.WriteString(v.Html())
		br.WriteString("</div>")
		br.WriteString("</div>")
	}
	br.WriteString("</div>")
	return br.String()
}

func (e *Entry) AddItem(label string, txt *Text) *Entry {
	if e.Items == nil {
		e.Items = make(map[string]Element)
	}
	e.Items[label] = txt
	return e
}

func (page *Page) SetHead(s string) *Page {
	page.Head = s
	return page
}

func (page *Page) SetCopyright(s string) *Page {
	page.Copyright = s
	return page
}

func (page *Page) AddPlainIntro(s string) *Page {
	page.Intros = append(page.Intros, NewText(s, WithTextTag(atom.P)))
	return page
}

func (page *Page) AddIntro(t *Text) *Page {
	page.Intros = append(page.Intros, t)
	return page
}

func (page *Page) AddEntry(e *Entry) *Page {
	page.Entries = append(page.Entries, e)
	return page
}

func (page *Page) AddTable(t *Table) *Page {
	page.Tables = append(page.Tables, t)
	return page
}

func (page *Page) AddButtonAction(s string, btn *Button) *Page {
	page.Actions = append(page.Actions, &Action{Instructions: NewText(s, WithTextTag(atom.P)), Button: btn})
	return page
}

func (page *Page) AddInviteCodeAction(s string, code string) *Page {
	page.Actions = append(page.Actions, &Action{Instructions: NewText(s, WithTextTag(atom.P)), InviteCode: code})
	return page
}

func (page *Page) AddOutro(t *Text) *Page {
	page.Outros = append(page.Outros, t)
	return page
}

func (page *Page) AddPlainOutro(s string) *Page {
	page.Outros = append(page.Outros, NewText(s, WithTextTag(atom.P)))
	return page
}

func (page *Page) Escape() {
	page.Head = html.EscapeString(page.Head)
	page.Copyright = html.EscapeString(page.Copyright)
}

func NewPage(title string) *Page {
	return &Page{
		Title:   title,
		Intros:  make([]Element, 0),
		Entries: make([]*Entry, 0),
		Actions: make([]*Action, 0),
		Outros:  make([]Element, 0),
		Tables:  make([]*Table, 0),
	}
}

func NewEntry(title string) *Entry {
	return &Entry{
		Title: NewText(title, WithTextTag(atom.P)),
		Items: make(map[string]Element),
	}
}

func WithTextTheme(s string) TextOption {
	return func(t *Text) {
		t.Theme = s
	}
}

func WithTextStyle(ms map[string]string) TextOption {
	return func(t *Text) {
		t.Style = ms
	}
}

func WithTextTag(tag atom.Atom) TextOption {
	return func(t *Text) {
		t.Tag = tag
	}
}

func WithTextColor(color string) TextOption {
	return func(t *Text) {
		t.Color = color
	}
}

func (button *Button) Html() string {
	return button.String()
}

func (button *Button) String() string {
	br := getBuffer()
	defer releaseBuffer(br)
	if button.Style == nil {
		button.Style = make(map[string]string)
	}
	if button.Color != "" {
		button.Style["color"] = button.Color
	}
	br.WriteString("<a class='button'")
	if button.Url != "" {
		br.WriteString(" href='" + button.Url + "'")
	}
	if len(button.Style) > 0 {
		br.WriteString(" style='")
		br.WriteString(button.Style.String())
		br.WriteString("'")
	}
	br.WriteString(">")
	br.WriteString(html.EscapeString(button.Text))
	br.WriteString("</a>")
	return br.String()
}

func (table *Table) SetHead(elements ...Element) {
	table.Header = elements
}

func (table *Table) AddCell(elements ...Element) {
	if table.Body == nil {
		table.Body = make([][]Element, 0)
	}
	table.Body = append(table.Body, elements)
}

func (table *Table) String() string {
	br := getBuffer()
	defer releaseBuffer(br)
	br.WriteString("<div class='table-wrapper'>")
	if table.Title != nil {
		br.WriteString("<div class='table-title'>")
		br.WriteString(table.Title.Html())
		br.WriteString("</div>")
	}
	br.WriteString("<table class='table'>")

	if len(table.Header) > 0 {
		br.WriteString("<thead>")
		br.WriteString("<tr>")
		for _, text := range table.Header {
			br.WriteString("<th>")
			br.WriteString(text.Html())
			br.WriteString("</th>")
		}
		br.WriteString("</tr>")
		br.WriteString("</thead>")
	}
	if len(table.Body) > 0 {
		br.WriteString("<tbody>")
		for _, cell := range table.Body {
			br.WriteString("<tr>")
			for _, text := range cell {
				br.WriteString("<td>")
				br.WriteString(text.Html())
				br.WriteString("</td>")
			}
			br.WriteString("</tr>")
		}
		br.WriteString("</tbody>")
	}
	br.WriteString("</table>")
	br.WriteString("</div>")
	return br.String()
}

func (text *Text) Html() string {
	return text.String()
}

func (text *Text) String() string {
	br := getBuffer()
	defer releaseBuffer(br)
	if text.Style == nil {
		text.Style = make(map[string]string)
	}
	if text.Color != "" {
		text.Style["color"] = text.Color
	}
	if text.Tag == 0 {
		text.Tag = atom.Span
	}
	br.WriteString("<")
	br.WriteString(text.Tag.String())
	if text.Theme != "" {
		br.WriteString(" class='text-")
		br.WriteString(text.Theme)
		br.WriteString("'")
	}
	if len(text.Style) > 0 {
		br.WriteString(" style='")
		br.WriteString(text.Style.String())
		br.WriteString("'")
	}
	br.WriteString(">")
	br.WriteString(html.EscapeString(text.Content))
	br.WriteString("</")
	br.WriteString(text.Tag.String())
	br.WriteString(">")
	return br.String()
}

func NewButton(label, link string, opts ...ButtonOption) *Button {
	btn := &Button{Text: label, Url: link}
	for _, cb := range opts {
		cb(btn)
	}
	return btn
}

func NewText(s string, opts ...TextOption) *Text {
	txt := &Text{Content: s, Tag: atom.Span}
	for _, cb := range opts {
		cb(txt)
	}
	return txt
}

func NewTable(title *Text) *Table {
	table := &Table{
		Title:  title,
		Header: make([]Element, 0),
		Body:   make([][]Element, 0),
	}
	return table
}