using System;
using System.Collections.Generic;
using System.Text;
using UnityEngine;

namespace FairyGUI.Utils
{
    /// <summary>
    /// 
    /// </summary>
    public class HtmlParser
    {
        public static HtmlParser inst = new HtmlParser();

        protected class TextFormat2 : TextFormat
        {
            public bool colorChanged;
        }

        protected List<TextFormat2> _textFormatStack;
        protected int _textFormatStackTop;
        protected TextFormat2 _format;
        protected List<HtmlElement> _elements;
        protected HtmlParseOptions _defaultOptions;

        static List<string> sHelperList1 = new List<string>();
        static List<string> sHelperList2 = new List<string>();

        public HtmlParser()
        {
            _textFormatStack = new List<TextFormat2>();
            _format = new TextFormat2();
            _defaultOptions = new HtmlParseOptions();
        }

        virtual public void Parse(string aSource, TextFormat defaultFormat, List<HtmlElement> elements, HtmlParseOptions parseOptions)
        {
            if (parseOptions == null)
                parseOptions = _defaultOptions;

            _elements = elements;
            _textFormatStackTop = 0;
            _format.CopyFrom(defaultFormat);
            _format.colorChanged = false;
            int skipText = 0;
            bool ignoreWhiteSpace = parseOptions.ignoreWhiteSpace;
            bool skipNextCR = false;
            string text;

            XMLIterator.Begin(aSource, true);
            while (XMLIterator.NextTag())
            {
                if (skipText == 0)
                {
                    text = XMLIterator.GetText(ignoreWhiteSpace);
                    if (text.Length > 0)
                    {
                        if (skipNextCR && text[0] == '\n')
                            text = text.Substring(1);
                        AppendText(text);
                    }
                }

                skipNextCR = false;
                switch (XMLIterator.tagName)
                {
                    case "b":
                        if (XMLIterator.tagType == XMLTagType.Start)
                        {
                            PushTextFormat();
                            _format.bold = true;
                        }
                        else
                            PopTextFormat();
                        break;

                    case "i":
                        if (XMLIterator.tagType == XMLTagType.Start)
                        {
                            PushTextFormat();
                            _format.italic = true;
                        }
                        else
                            PopTextFormat();
                        break;

                    case "u":
                        if (XMLIterator.tagType == XMLTagType.Start)
                        {
                            PushTextFormat();
                            _format.underline = true;
                        }
                        else
                            PopTextFormat();
                        break;

                    case "strike":
                        if (XMLIterator.tagType == XMLTagType.Start)
                        {
                            PushTextFormat();
                            _format.strikethrough = true;
                        }
                        else
                            PopTextFormat();
                        break;

                    case "sub":
                        {
                            if (XMLIterator.tagType == XMLTagType.Start)
                            {
                                PushTextFormat();
                                _format.specialStyle = TextFormat.SpecialStyle.Subscript;
                            }
                            else
                                PopTextFormat();
                        }
                        break;

                    case "sup":
                        {
                            if (XMLIterator.tagType == XMLTagType.Start)
                            {
                                PushTextFormat();
                                _format.specialStyle = TextFormat.SpecialStyle.Superscript;
                            }
                            else
                                PopTextFormat();
                        }
                        break;

                    case "font":
                        if (XMLIterator.tagType == XMLTagType.Start)
                        {
                            PushTextFormat();

                            _format.size = XMLIterator.GetAttributeInt("size", _format.size);
                            string color = XMLIterator.GetAttribute("color");
                            if (color != null)
                            {
                                string[] parts = color.Split(',');
                                if (parts.Length == 1)
                                {
                                    _format.color = ToolSet.ConvertFromHtmlColor(color);
                                    _format.gradientColor = null;
                                    _format.colorChanged = true;
                                }
                                else
                                {
                                    if (_format.gradientColor == null)
                                        _format.gradientColor = new Color32[4];
                                    _format.gradientColor[0] = ToolSet.ConvertFromHtmlColor(parts[0]);
                                    _format.gradientColor[1] = ToolSet.ConvertFromHtmlColor(parts[1]);
                                    if (parts.Length > 2)
                                    {
                                        _format.gradientColor[2] = ToolSet.ConvertFromHtmlColor(parts[2]);
                                        if (parts.Length > 3)
                                            _format.gradientColor[3] = ToolSet.ConvertFromHtmlColor(parts[3]);
                                        else
                                            _format.gradientColor[3] = _format.gradientColor[2];
                                    }
                                    else
                                    {
                                        _format.gradientColor[2] = _format.gradientColor[0];
                                        _format.gradientColor[3] = _format.gradientColor[1];
                                    }
                                }
                            }
                        }
                        else if (XMLIterator.tagType == XMLTagType.End)
                            PopTextFormat();
                        break;

                    case "br":
                        AppendText("\n");
                        break;

                    case "img":
                        if (XMLIterator.tagType == XMLTagType.Start || XMLIterator.tagType == XMLTagType.Void)
                        {
                            HtmlElement element = HtmlElement.GetElement(HtmlElementType.Image);
                            element.FetchAttributes();
                            element.name = element.GetString("name");
                            element.format.align = _format.align;
                            _elements.Add(element);
                        }
                        break;

                    case "a":
                        if (XMLIterator.tagType == XMLTagType.Start)
                        {
                            PushTextFormat();

                            _format.underline = _format.underline || parseOptions.linkUnderline;
                            if (!_format.colorChanged && parseOptions.linkColor.a != 0)
                                _format.color = parseOptions.linkColor;

                            HtmlElement element = HtmlElement.GetElement(HtmlElementType.Link);
                            element.FetchAttributes();
                            element.name = element.GetString("name");
                            element.format.align = _format.align;
                            _elements.Add(element);
                        }
                        else if (XMLIterator.tagType == XMLTagType.End)
                        {
                            PopTextFormat();

                            HtmlElement element = HtmlElement.GetElement(HtmlElementType.LinkEnd);
                            _elements.Add(element);
                        }
                        break;

                    case "input":
                        {
                            HtmlElement element = HtmlElement.GetElement(HtmlElementType.Input);
                            element.FetchAttributes();
                            element.name = element.GetString("name");
                            element.format.CopyFrom(_format);
                            _elements.Add(element);
                        }
                        break;

                    case "select":
                        {
                            if (XMLIterator.tagType == XMLTagType.Start || XMLIterator.tagType == XMLTagType.Void)
                            {
                                HtmlElement element = HtmlElement.GetElement(HtmlElementType.Select);
                                element.FetchAttributes();
                                if (XMLIterator.tagType == XMLTagType.Start)
                                {
                                    sHelperList1.Clear();
                                    sHelperList2.Clear();
                                    while (XMLIterator.NextTag())
                                    {
                                        if (XMLIterator.tagName == "select")
                                            break;

                                        if (XMLIterator.tagName == "option")
                                        {
                                            if (XMLIterator.tagType == XMLTagType.Start || XMLIterator.tagType == XMLTagType.Void)
                                                sHelperList2.Add(XMLIterator.GetAttribute("value", string.Empty));
                                            else
                                                sHelperList1.Add(XMLIterator.GetText());
                                        }
                                    }
                                    element.Set("items", sHelperList1.ToArray());
                                    element.Set("values", sHelperList2.ToArray());
                                }
                                element.name = element.GetString("name");
                                element.format.CopyFrom(_format);
                                _elements.Add(element);
                            }
                        }
                        break;

                    case "p":
                        if (XMLIterator.tagType == XMLTagType.Start)
                        {
                            PushTextFormat();
                            string align = XMLIterator.GetAttribute("align");
                            switch (align)
                            {
                                case "center":
                                    _format.align = AlignType.Center;
                                    break;
                                case "right":
                                    _format.align = AlignType.Right;
                                    break;
                            }
                            if (!IsNewLine())
                                AppendText("\n");
                        }
                        else if (XMLIterator.tagType == XMLTagType.End)
                        {
                            AppendText("\n");
                            skipNextCR = true;

                            PopTextFormat();
                        }
                        break;

                    case "ui":
                    case "div":
                    case "li":
                        if (XMLIterator.tagType == XMLTagType.Start)
                        {
                            if (!IsNewLine())
                                AppendText("\n");
                        }
                        else
                        {
                            AppendText("\n");
                            skipNextCR = true;
                        }
                        break;

                    case "html":
                    case "body":
                        //full html
                        ignoreWhiteSpace = true;
                        break;

                    case "head":
                    case "style":
                    case "script":
                    case "form":
                        if (XMLIterator.tagType == XMLTagType.Start)
                            skipText++;
                        else if (XMLIterator.tagType == XMLTagType.End)
                            skipText--;
                        break;
                }
            }

            if (skipText == 0)
            {
                text = XMLIterator.GetText(ignoreWhiteSpace);
                if (text.Length > 0)
                {
                    if (skipNextCR && text[0] == '\n')
                        text = text.Substring(1);
                    AppendText(text);
                }
            }

            _elements = null;
        }

        protected void PushTextFormat()
        {
            TextFormat2 tf;
            if (_textFormatStack.Count <= _textFormatStackTop)
            {
                tf = new TextFormat2();
                _textFormatStack.Add(tf);
            }
            else
                tf = _textFormatStack[_textFormatStackTop];
            tf.CopyFrom(_format);
            tf.colorChanged = _format.colorChanged;
            _textFormatStackTop++;
        }

        protected void PopTextFormat()
        {
            if (_textFormatStackTop > 0)
            {
                TextFormat2 tf = _textFormatStack[_textFormatStackTop - 1];
                _format.CopyFrom(tf);
                _format.colorChanged = tf.colorChanged;
                _textFormatStackTop--;
            }
        }

        protected bool IsNewLine()
        {
            if (_elements.Count > 0)
            {
                HtmlElement element = _elements[_elements.Count - 1];
                if (element != null && element.type == HtmlElementType.Text)
                    return element.text.EndsWith("\n");
                else
                    return false;
            }

            return true;
        }

        protected void AppendText(string text)
        {
            HtmlElement element;
            if (_elements.Count > 0)
            {
                element = _elements[_elements.Count - 1];
                if (element.type == HtmlElementType.Text && element.format.EqualStyle(_format))
                {
                    element.text += text;
                    return;
                }
            }

            element = HtmlElement.GetElement(HtmlElementType.Text);
            element.text = text;
            element.format.CopyFrom(_format);
            _elements.Add(element);
        }
    }
}