using System;
using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System.Linq;


namespace TMPro
{

    /// <summary>
    /// Contains the font asset for the specified font weight styles.
    /// </summary>
    [Serializable]
    public struct TMP_FontWeights
    {
        public TMP_FontAsset regularTypeface;
        public TMP_FontAsset italicTypeface;
    }



    [Serializable]
    public class TMP_FontAsset : TMP_Asset
    {
        /// <summary>
        /// Default Font Asset used as last resort when glyphs are missing.
        /// </summary>
        public static TMP_FontAsset defaultFontAsset
        {
            get
            {
                if (s_defaultFontAsset == null)
                {
                    s_defaultFontAsset = Resources.Load<TMP_FontAsset>("Fonts & Materials/LiberationSans SDF");
                }

                return s_defaultFontAsset;
            }
        }
        private static TMP_FontAsset s_defaultFontAsset;


        public enum FontAssetTypes { None = 0, SDF = 1, Bitmap = 2 };
        public FontAssetTypes fontAssetType;
        
        /// <summary>
        /// The general information about the font.
        /// </summary>
        public FaceInfo fontInfo
        { get { return m_fontInfo; } }

        [SerializeField]
        private FaceInfo m_fontInfo;

        [SerializeField]
        public Texture2D atlas; // Should add a property to make this read-only.


        // Glyph Info

        [SerializeField]
        private List<TMP_Glyph> m_glyphInfoList;

        public Dictionary<int, TMP_Glyph> characterDictionary
        {
            get
            {
                if (m_characterDictionary == null)
                    ReadFontDefinition();

                return m_characterDictionary;
            }
        }
        private Dictionary<int, TMP_Glyph> m_characterDictionary;


        /// <summary>
        /// Dictionary containing the kerning data
        /// </summary>
        public Dictionary<int, KerningPair> kerningDictionary
        {
            get { return m_kerningDictionary; }
        }
        private Dictionary<int, KerningPair> m_kerningDictionary;

        /// <summary>
        /// 
        /// </summary>
        public KerningTable kerningInfo
        {
            get { return m_kerningInfo; }
        }

        [SerializeField]
        private KerningTable m_kerningInfo;

        [SerializeField]
        #pragma warning disable 0169 // Property is used to create an empty Kerning Pair in the editor.
        private KerningPair m_kerningPair;  // Used for creating a new kerning pair in Editor Panel.


        /// <summary>
        /// List which contains the Fallback font assets for this font.
        /// </summary>
        [SerializeField]
        public List<TMP_FontAsset> fallbackFontAssets;


        // TODO : Not implemented yet.
        [SerializeField]
        public FontCreationSetting fontCreationSettings;

        // FONT WEIGHTS
        [SerializeField]
        public TMP_FontWeights[] fontWeights = new TMP_FontWeights[10];

        private int[] m_characterSet; // Array containing all the characters in this font asset.

        public float normalStyle = 0;
        public float normalSpacingOffset = 0;

        public float boldStyle = 0.75f;
        public float boldSpacing = 7f;
        public byte italicStyle = 35;
        public byte tabSize = 10;

        private byte m_oldTabSize;


        void OnEnable()
        {
            //Debug.Log("OnEnable has been called on " + this.name);
        }


        void OnDisable()
        {
            //Debug.Log("TextMeshPro Font Asset [" + this.name + "] has been disabled!");
        }


#if UNITY_EDITOR
        /// <summary>
        /// 
        /// </summary>
        void OnValidate()
        {
            if (m_oldTabSize != tabSize)
            {
                m_oldTabSize = tabSize;
                ReadFontDefinition();
            }
        }
#endif


        /// <summary>
        /// 
        /// </summary>
        /// <param name="faceInfo"></param>
        public void AddFaceInfo(FaceInfo faceInfo)
        {
            m_fontInfo = faceInfo;
        }


        /// <summary>
        /// 
        /// </summary>
        /// <param name="glyphInfo"></param>
        public void AddGlyphInfo(TMP_Glyph[] glyphInfo)
        {
            m_glyphInfoList = new List<TMP_Glyph>();
            int characterCount = glyphInfo.Length;

            m_fontInfo.CharacterCount = characterCount;
            m_characterSet = new int[characterCount];

            for (int i = 0; i < characterCount; i++)
            {
                TMP_Glyph g = new TMP_Glyph();
                g.id = glyphInfo[i].id;
                g.x = glyphInfo[i].x;
                g.y = glyphInfo[i].y;
                g.width = glyphInfo[i].width;
                g.height = glyphInfo[i].height;
                g.xOffset = glyphInfo[i].xOffset;
                g.yOffset = (glyphInfo[i].yOffset);
                g.xAdvance = glyphInfo[i].xAdvance;
                g.scale = 1;

                m_glyphInfoList.Add(g);

                // While iterating through list of glyphs, find the Descender & Ascender for this GlyphSet.
                //m_fontInfo.Ascender = Mathf.Max(m_fontInfo.Ascender, glyphInfo[i].yOffset);
                //m_fontInfo.Descender = Mathf.Min(m_fontInfo.Descender, glyphInfo[i].yOffset - glyphInfo[i].height);
                //Debug.Log(m_fontInfo.Ascender + "  " + m_fontInfo.Descender);
                m_characterSet[i] = g.id; // Add Character ID to Array to make it easier to get the kerning pairs.
            }

            // Sort List by ID.
            m_glyphInfoList = m_glyphInfoList.OrderBy(s => s.id).ToList();
        }


        /// <summary>
        /// 
        /// </summary>
        /// <param name="kerningTable"></param>
        public void AddKerningInfo(KerningTable kerningTable)
        {
            m_kerningInfo = kerningTable;
        }


        /// <summary>
        /// 
        /// </summary>
        public void ReadFontDefinition()
        {
            //Debug.Log("Reading Font Definition for " + this.name + ".");
            // Make sure that we have a Font Asset file assigned.
            if (m_fontInfo == null)
            {
                return;
            }

            // Check Font Asset type
            //Debug.Log(name + "   " + fontAssetType);

            // Create new instance of GlyphInfo Dictionary for fast access to glyph info.
            m_characterDictionary = new Dictionary<int, TMP_Glyph>();
            for (int i = 0; i < m_glyphInfoList.Count; i++)
            {
                TMP_Glyph glyph = m_glyphInfoList[i];

                if (!m_characterDictionary.ContainsKey(glyph.id))
                    m_characterDictionary.Add(glyph.id, glyph);

                // Compatibility
                if (glyph.scale == 0) glyph.scale = 1;
            }


            //Debug.Log("PRE: BaseLine:" + m_fontInfo.Baseline + "  Ascender:" + m_fontInfo.Ascender + "  Descender:" + m_fontInfo.Descender); // + "  Centerline:" + m_fontInfo.CenterLine);

            TMP_Glyph temp_charInfo = new TMP_Glyph();

            // Add Character (10) LineFeed, (13) Carriage Return & Space (32) to Dictionary if they don't exists.
            if (m_characterDictionary.ContainsKey(32))
            {
                m_characterDictionary[32].width = m_characterDictionary[32].xAdvance; // m_fontInfo.Ascender / 5;
                m_characterDictionary[32].height = m_fontInfo.Ascender - m_fontInfo.Descender;
                m_characterDictionary[32].yOffset= m_fontInfo.Ascender;
                m_characterDictionary[32].scale = 1;
            }
            else
            {
                //Debug.Log("Adding Character 32 (Space) to Dictionary for Font (" + m_fontInfo.Name + ").");
                temp_charInfo = new TMP_Glyph();
                temp_charInfo.id = 32;
                temp_charInfo.x = 0; 
                temp_charInfo.y = 0;
                temp_charInfo.width = m_fontInfo.Ascender / 5;
                temp_charInfo.height = m_fontInfo.Ascender - m_fontInfo.Descender;
                temp_charInfo.xOffset = 0; 
                temp_charInfo.yOffset = m_fontInfo.Ascender; 
                temp_charInfo.xAdvance = m_fontInfo.PointSize / 4;
                temp_charInfo.scale = 1;
                m_characterDictionary.Add(32, temp_charInfo);
            }

            // Add Non-Breaking Space (160)
            if (!m_characterDictionary.ContainsKey(160))
            {
                temp_charInfo = TMP_Glyph.Clone(m_characterDictionary[32]);
                m_characterDictionary.Add(160, temp_charInfo);
            }

            // Add Zero Width Space (8203)
            if (!m_characterDictionary.ContainsKey(8203))
            {
                temp_charInfo = TMP_Glyph.Clone(m_characterDictionary[32]);
                temp_charInfo.width = 0;
                temp_charInfo.xAdvance = 0;
                m_characterDictionary.Add(8203, temp_charInfo);
            }

            //Add Zero Width no-break space (8288)
            if (!m_characterDictionary.ContainsKey(8288))
            {
                temp_charInfo = TMP_Glyph.Clone(m_characterDictionary[32]);
                temp_charInfo.width = 0;
                temp_charInfo.xAdvance = 0;
                m_characterDictionary.Add(8288, temp_charInfo);
            }

            // Add Linefeed (10)
            if (m_characterDictionary.ContainsKey(10) == false)
            {
                //Debug.Log("Adding Character 10 (Linefeed) to Dictionary for Font (" + m_fontInfo.Name + ").");

                temp_charInfo = new TMP_Glyph();
                temp_charInfo.id = 10;
                temp_charInfo.x = 0; // m_characterDictionary[32].x;
                temp_charInfo.y = 0; // m_characterDictionary[32].y;
                temp_charInfo.width = 10; // m_characterDictionary[32].width;
                temp_charInfo.height = m_characterDictionary[32].height;
                temp_charInfo.xOffset = 0; // m_characterDictionary[32].xOffset;
                temp_charInfo.yOffset = m_characterDictionary[32].yOffset;
                temp_charInfo.xAdvance = 0;
                temp_charInfo.scale = 1;
                m_characterDictionary.Add(10, temp_charInfo);

                if (!m_characterDictionary.ContainsKey(13))
                    m_characterDictionary.Add(13, temp_charInfo);
            }

            // Add Tab Character to Dictionary. Tab is Tab Size * Space Character Width.
            if (m_characterDictionary.ContainsKey(9) == false)
            {
                //Debug.Log("Adding Character 9 (Tab) to Dictionary for Font (" + m_fontInfo.Name + ").");

                temp_charInfo = new TMP_Glyph();
                temp_charInfo.id = 9;
                temp_charInfo.x = m_characterDictionary[32].x;
                temp_charInfo.y = m_characterDictionary[32].y;
                temp_charInfo.width = m_characterDictionary[32].width * tabSize + (m_characterDictionary[32].xAdvance - m_characterDictionary[32].width) * (tabSize - 1);
                temp_charInfo.height = m_characterDictionary[32].height;
                temp_charInfo.xOffset = m_characterDictionary[32].xOffset;
                temp_charInfo.yOffset = m_characterDictionary[32].yOffset;
                temp_charInfo.xAdvance = m_characterDictionary[32].xAdvance * tabSize;
                temp_charInfo.scale = 1;
                m_characterDictionary.Add(9, temp_charInfo);
            }

            // Centerline is located at the center of character like { or in the middle of the lowercase o.
            //m_fontInfo.CenterLine = m_characterDictionary[111].yOffset - m_characterDictionary[111].height * 0.5f;

            // Tab Width is using the same xAdvance as space (32).
            m_fontInfo.TabWidth = m_characterDictionary[9].xAdvance;

            // Set Cap Height
            if (m_fontInfo.CapHeight == 0 && m_characterDictionary.ContainsKey(72))
                m_fontInfo.CapHeight = m_characterDictionary[72].yOffset;

            // Adjust Font Scale for compatibility reasons
            if (m_fontInfo.Scale == 0)
                m_fontInfo.Scale = 1.0f;

            // Set Strikethrough Offset (if needed)
            if (m_fontInfo.strikethrough == 0)
                m_fontInfo.strikethrough = m_fontInfo.CapHeight / 2.5f;

            // Set Padding value for legacy font assets.
            if (m_fontInfo.Padding == 0)
            {
                if (material.HasProperty(ShaderUtilities.ID_GradientScale))
                    m_fontInfo.Padding = material.GetFloat(ShaderUtilities.ID_GradientScale) - 1;
            }

            // Populate Dictionary with Kerning Information
            m_kerningDictionary = new Dictionary<int, KerningPair>();
            List<KerningPair> pairs = m_kerningInfo.kerningPairs;

            //Debug.Log(m_fontInfo.Name + " has " + pairs.Count +  " Kerning Pairs.");
            for (int i = 0; i < pairs.Count; i++)
            {
                KerningPair pair = pairs[i];

                // Convert legacy kerning data
                if (pair.xOffset != 0)
                    pairs[i].ConvertLegacyKerningData();

                KerningPairKey uniqueKey = new KerningPairKey(pair.firstGlyph, pair.secondGlyph);

                if (m_kerningDictionary.ContainsKey((int)uniqueKey.key) == false)
                {
                    m_kerningDictionary.Add((int)uniqueKey.key, pair);
                }
                else
                {
                    if (!TMP_Settings.warningsDisabled)
                        Debug.LogWarning("Kerning Key for [" + uniqueKey.ascii_Left + "] and [" + uniqueKey.ascii_Right + "] already exists.");
                }
            }


            // Compute Hashcode for the font asset name
            hashCode = TMP_TextUtilities.GetSimpleHashCode(this.name);

            // Compute Hashcode for the material name
            materialHashCode = TMP_TextUtilities.GetSimpleHashCode(material.name);

            // Unload font atlas texture
            //ShaderUtilities.GetShaderPropertyIDs();
            //Resources.UnloadAsset(material.GetTexture(ShaderUtilities.ID_MainTex));

            // Initialize Font Weights if needed
            //InitializeFontWeights();
        }


        /// <summary>
        /// Function to sort the list of glyphs.
        /// </summary>
        public void SortGlyphs()
        {
            if (m_glyphInfoList == null || m_glyphInfoList.Count == 0) return;

            m_glyphInfoList = m_glyphInfoList.OrderBy(item => item.id).ToList();
        }



        /// <summary>
        /// Function to check if a certain character exists in the font asset.
        /// </summary>
        /// <param name="character"></param>
        /// <returns></returns>
        public bool HasCharacter(int character)
        {
            if (m_characterDictionary == null)
                return false;

            if (m_characterDictionary.ContainsKey(character))
                return true;

            return false;
        }


        /// <summary>
        /// Function to check if a certain character exists in the font asset.
        /// </summary>
        /// <param name="character"></param>
        /// <returns></returns>
        public bool HasCharacter(char character)
        {
            if (m_characterDictionary == null)
                return false;

            if (m_characterDictionary.ContainsKey(character))
                return true;

            return false;
        }


        /// <summary>
        /// Function to check if a character is contained in a font asset with the option to also check through fallback font assets.
        /// </summary>
        /// <param name="character"></param>
        /// <param name="searchFallbacks"></param>
        /// <returns></returns>
        public bool HasCharacter(char character, bool searchFallbacks)
        {
            if (m_characterDictionary == null)
                return false;

            // Check font asset
            if (m_characterDictionary.ContainsKey(character))
                return true;

            
            if (searchFallbacks)
            {
                // Check Font Asset Fallback fonts.
                if (fallbackFontAssets != null && fallbackFontAssets.Count > 0)
                {
                    for (int i = 0; i < fallbackFontAssets.Count && fallbackFontAssets[i] != null; i++)
                    {
                        if (fallbackFontAssets[i].characterDictionary != null && fallbackFontAssets[i].characterDictionary.ContainsKey(character))
                            return true;
                    }
                }

                // Check general fallback font assets.
                if (TMP_Settings.fallbackFontAssets != null && TMP_Settings.fallbackFontAssets.Count > 0)
                {
                    for (int i = 0; i < TMP_Settings.fallbackFontAssets.Count && TMP_Settings.fallbackFontAssets[i] != null; i++)
                    {
                        if (TMP_Settings.fallbackFontAssets[i].characterDictionary != null && TMP_Settings.fallbackFontAssets[i].characterDictionary.ContainsKey(character))
                            return true;
                    }
                }
            }

            return false;
        }


        /// <summary>
        /// Function to check if certain characters exists in the font asset. Function returns a list of missing characters.
        /// </summary>
        /// <param name="character"></param>
        /// <returns></returns>
        public bool HasCharacters(string text, out List<char> missingCharacters)
        {
            if (m_characterDictionary == null)
            {
                missingCharacters = null;
                return false;
            }

            missingCharacters = new List<char>();

            for (int i = 0; i < text.Length; i++)
            {
                if (!m_characterDictionary.ContainsKey(text[i]))
                    missingCharacters.Add(text[i]);
            }

            if (missingCharacters.Count == 0)
                return true;

            return false;
        }


        /// <summary>
        /// Function to check if certain characters exists in the font asset. Function returns false if any characters are missing.
        /// </summary>
        /// <param name="text">String containing the characters to check</param>
        /// <returns></returns>
        public bool HasCharacters(string text)
        {
            if (m_characterDictionary == null)
                return false;

            for (int i = 0; i < text.Length; i++)
            {
                if (!m_characterDictionary.ContainsKey(text[i]))
                    return false;
            }

            return true;
        }


        /// <summary>
        /// Function to extract all the characters from a font asset.
        /// </summary>
        /// <param name="fontAsset"></param>
        /// <returns></returns>
        public static string GetCharacters(TMP_FontAsset fontAsset)
        {
            string characters = string.Empty;

            for (int i = 0; i < fontAsset.m_glyphInfoList.Count; i++)
            {
                characters += (char)fontAsset.m_glyphInfoList[i].id;
            }

            return characters;
        }


        /// <summary>
        /// Function which returns an array that contains all the characters from a font asset.
        /// </summary>
        /// <param name="fontAsset"></param>
        /// <returns></returns>
        public static int[] GetCharactersArray(TMP_FontAsset fontAsset)
        {
            int[] characters = new int[fontAsset.m_glyphInfoList.Count];

            for (int i = 0; i < fontAsset.m_glyphInfoList.Count; i++)
            {
                characters[i] = fontAsset.m_glyphInfoList[i].id;
            }

            return characters;
        }

    }
}