// "Therefore those skilled at the unorthodox

// are infinite as heaven and earth,

// inexhaustible as the great rivers.

// When they come to an end,

// they begin again,

// like the days and months;

// they die and are reborn,

// like the four seasons."

//

// - Sun Tsu,

// "The Art of War"

using System;

using System.Collections.Generic;

using TheArtOfDev.HtmlRenderer.Adapters;

using TheArtOfDev.HtmlRenderer.Core.Entities;

using TheArtOfDev.HtmlRenderer.Core.Parse;

using TheArtOfDev.HtmlRenderer.Core.Utils;

namespace TheArtOfDev.HtmlRenderer.Core

{

/// <summary>

/// Holds parsed stylesheet css blocks arranged by media and classes.<br/>

/// <seealso cref="CssBlock"/>

/// </summary>

/// <remarks>

/// To learn more about CSS blocks visit CSS spec: http://www.w3.org/TR/CSS21/syndata.html#block

/// </remarks>

public sealed class CssData

{

#region Fields and Consts

/// <summary>

/// used to return empty array

/// </summary>

private static readonly List<CssBlock> _emptyArray = new List<CssBlock>();

/// <summary>

/// dictionary of media type to dictionary of css class name to the cssBlocks collection with all the data.

/// </summary>

private readonly Dictionary<string, Dictionary<string, List<CssBlock>>> _mediaBlocks = new Dictionary<string, Dictionary<string, List<CssBlock>>>(StringComparer.InvariantCultureIgnoreCase);

#endregion

/// <summary>

/// Init.

/// </summary>

internal CssData()

{

_mediaBlocks.Add("all", new Dictionary<string, List<CssBlock>>(StringComparer.InvariantCultureIgnoreCase));

}

/// <summary>

/// Parse the given stylesheet to <see cref="CssData"/> object.<br/>

/// If <paramref name="combineWithDefault"/> is true the parsed css blocks are added to the

/// default css data (as defined by W3), merged if class name already exists. If false only the data in the given stylesheet is returned.

/// </summary>

/// <seealso cref="http://www.w3.org/TR/CSS21/sample.html"/>

/// <param name="adapter">Platform adapter</param>

/// <param name="stylesheet">the stylesheet source to parse</param>

/// <param name="combineWithDefault">true - combine the parsed css data with default css data, false - return only the parsed css data</param>

/// <returns>the parsed css data</returns>

public static CssData Parse(RAdapter adapter, string stylesheet, bool combineWithDefault = true)

{

CssParser parser = new CssParser(adapter);

return parser.ParseStyleSheet(stylesheet, combineWithDefault);

}

/// <summary>

/// dictionary of media type to dictionary of css class name to the cssBlocks collection with all the data

/// </summary>

internal IDictionary<string, Dictionary<string, List<CssBlock>>> MediaBlocks

{

get { return _mediaBlocks; }

}

/// <summary>

/// Check if there are css blocks for the given class selector.

/// </summary>

/// <param name="className">the class selector to check for css blocks by</param>

/// <param name="media">optional: the css media type (default - all)</param>

/// <returns>true - has css blocks for the class, false - otherwise</returns>

public bool ContainsCssBlock(string className, string media = "all")

{

Dictionary<string, List<CssBlock>> mid;

return _mediaBlocks.TryGetValue(media, out mid) && mid.ContainsKey(className);

}

/// <summary>

/// Get collection of css blocks for the requested class selector.<br/>

/// the <paramref name="className"/> can be: class name, html element name, html element and

/// class name (elm.class), hash tag with element id (#id).<br/>

/// returned all the blocks that word on the requested class selector, it can contain simple

/// selector or hierarchy selector.

/// </summary>

/// <param name="className">the class selector to get css blocks by</param>

/// <param name="media">optional: the css media type (default - all)</param>

/// <returns>collection of css blocks, empty collection if no blocks exists (never null)</returns>

public IEnumerable<CssBlock> GetCssBlock(string className, string media = "all")

{

List<CssBlock> block = null;

Dictionary<string, List<CssBlock>> mid;

if (_mediaBlocks.TryGetValue(media, out mid))

{

mid.TryGetValue(className, out block);

}

return block ?? _emptyArray;

}

/// <summary>

/// Add the given css block to the css data, merging to existing block if required.

/// </summary>

/// <remarks>

/// If there is no css blocks for the same class it will be added to data collection.<br/>

/// If there is already css blocks for the same class it will check for each existing block

/// if the hierarchical selectors match (or not exists). if do the two css blocks will be merged into

/// one where the new block properties overwrite existing if needed. if the new block doesn't mach any

/// existing it will be added either to the beginning of the list if it has no hierarchical selectors or at the end.<br/>

/// Css block without hierarchical selectors must be added to the beginning of the list so more specific block

/// can overwrite it when the style is applied.

/// </remarks>

/// <param name="media">the media type to add the CSS to</param>

/// <param name="cssBlock">the css block to add</param>

public void AddCssBlock(string media, CssBlock cssBlock)

{

Dictionary<string, List<CssBlock>> mid;

if (!_mediaBlocks.TryGetValue(media, out mid))

{

mid = new Dictionary<string, List<CssBlock>>(StringComparer.InvariantCultureIgnoreCase);

_mediaBlocks.Add(media, mid);

}

if (!mid.ContainsKey(cssBlock.Class))

{

var list = new List<CssBlock>();

list.Add(cssBlock);

mid[cssBlock.Class] = list;

}

else

{

bool merged = false;

var list = mid[cssBlock.Class];

foreach (var block in list)

{

if (block.EqualsSelector(cssBlock))

{

merged = true;

block.Merge(cssBlock);

break;

}

}

if (!merged)

{

// general block must be first

if (cssBlock.Selectors == null)

list.Insert(0, cssBlock);

else

list.Add(cssBlock);

}

}

}

/// <summary>

/// Combine this CSS data blocks with <paramref name="other"/> CSS blocks for each media.<br/>

/// Merge blocks if exists in both.

/// </summary>

/// <param name="other">the CSS data to combine with</param>

public void Combine(CssData other)

{

ArgChecker.AssertArgNotNull(other, "other");

// for each media block

foreach (var mediaBlock in other.MediaBlocks)

{

// for each css class in the media block

foreach (var bla in mediaBlock.Value)

{

// for each css block of the css class

foreach (var cssBlock in bla.Value)

{

// combine with this

AddCssBlock(mediaBlock.Key, cssBlock);

}

}

}

}

/// <summary>

/// Create deep copy of the css data with cloned css blocks.

/// </summary>

/// <returns>cloned object</returns>

public CssData Clone()

{

var clone = new CssData();

foreach (var mid in _mediaBlocks)

{

var cloneMid = new Dictionary<string, List<CssBlock>>(StringComparer.InvariantCultureIgnoreCase);

foreach (var blocks in mid.Value)

{

var cloneList = new List<CssBlock>();

foreach (var cssBlock in blocks.Value)

{

cloneList.Add(cssBlock.Clone());

}

cloneMid[blocks.Key] = cloneList;

}

clone._mediaBlocks[mid.Key] = cloneMid;

}

return clone;

}

}

}