#include "../include/Text.hpp"
#include "../include/Cache.hpp"
#include "../include/Gif.hpp"
#include <SFML/Graphics/RectangleShape.hpp>
#include <cmath>

namespace dchat
{
    const float TAB_WIDTH = 4.0f;
    const float EMOJI_PADDING = 5.0f;
    const float EMOJI_SCALE_WITH_TEXT = 1.0f;
    const float EMOJI_SCALE_STANDALONE = 5.0f;
    
    Text::Text(const sf::Font *_font) : 
        font(_font),
        characterSize(0),
        maxWidth(0.0f),
        color(sf::Color::White),
        dirty(false),
        plainText(false),
        totalHeight(0.0f)
    {
        
    }
    
    Text::Text(const sf::String &_str, const sf::Font *_font, unsigned int _characterSize, float _maxWidth, bool _plainText) : 
        font(_font),
        characterSize(_characterSize),
        vertices(sf::PrimitiveType::Quads),
        maxWidth(_maxWidth),
        color(sf::Color::White),
        dirty(true),
        plainText(_plainText),
        totalHeight(0.0f),
        lineSpacing(0.0f)
    {
        setString(_str);
    }
    
    void Text::setString(const sf::String &str)
    {
        if(str != this->str)
        {
            this->str = str;
            dirty = true;
            textElements.clear();
            stringSplitElements(this->str, 0);
        }
    }
    
    void Text::appendStringNewLine(const sf::String &str)
    {
        usize prevSize = this->str.getSize();
        this->str += '\n';
        this->str += str;
        dirty = true;
        stringSplitElements(this->str, prevSize);
    }
    
    void Text::setPosition(float x, float y)
    {
        position.x = x;
        position.y = y;
    }
    
    void Text::setPosition(const sf::Vector2f &position)
    {
        this->position = position;
    }
    
    void Text::setMaxWidth(float maxWidth)
    {
        if(maxWidth != this->maxWidth)
        {
            this->maxWidth = maxWidth;
            dirty = true;
        }
    }
    
    void Text::setCharacterSize(unsigned int characterSize)
    {
        if(characterSize != this->characterSize)
        {
            this->characterSize = characterSize;
            dirty = true;
        }
    }
    
    void Text::setFillColor(sf::Color color)
    {
        if(color != this->color)
        {
            this->color = color;
            dirty = true;
        }
    }
    
    void Text::setLineSpacing(float lineSpacing)
    {
        if(lineSpacing != this->lineSpacing)
        {
            this->lineSpacing = lineSpacing;
            dirty = true;
        }
    }
    
    float Text::getHeight() const
    {
        return totalHeight;
    }
    
    void Text::stringSplitElements(sf::String &stringToSplit, usize startIndex)
    {
        if(plainText)
        {
            StringViewUtf32 wholeStr(&stringToSplit[startIndex], stringToSplit.getSize() - startIndex);
            textElements.push_back({ wholeStr, TextElement::Type::TEXT });
            return;
        }
        
        size_t offset = startIndex;
        while(offset < stringToSplit.getSize())
        {
            size_t stringStart = offset;
            size_t foundStartIndex = stringToSplit.find("[emoji](", offset);
            size_t foundEndIndex = -1;
            if(foundStartIndex != -1)
            {
                offset += (foundStartIndex + 8);
                foundEndIndex = stringToSplit.find(")", offset);
            }
            
            if(foundEndIndex != -1)
            {
                StringViewUtf32 beforeEmojiStr(&stringToSplit[stringStart], foundStartIndex - stringStart);
                textElements.push_back({ beforeEmojiStr, TextElement::Type::TEXT });
                
                StringViewUtf32 url(&stringToSplit[offset], foundEndIndex - offset);
                textElements.push_back({ url, TextElement::Type::EMOJI });
                offset = foundEndIndex + 1;
            }
            else
            {
                StringViewUtf32 strToEnd(&stringToSplit[stringStart], stringToSplit.getSize() - stringStart);
                textElements.push_back({ strToEnd, TextElement::Type::TEXT });
                offset = stringToSplit.getSize();
            }
        }
        
        for(std::vector<TextElement>::iterator it = textElements.begin(); it != textElements.end();)
        {
            if(it->text.size == 0)
                it = textElements.erase(it);
            else
                ++it;
        }
    }
    
    // Logic loosely based on https://github.com/SFML/SFML/wiki/Source:-CurvedText
    void Text::updateGeometry()
    {
        vertices.clear();
        float hspace = font->getGlyph(' ', characterSize, false).advance;
        float vspace = font->getLineSpacing(characterSize);
        
        sf::Vector2f glyphPos;
        sf::Uint32 prevCodePoint = 0;
        size_t lastSpacingWordWrapIndex = -1;
        float lastSpacingAccumulatedOffset = 0.0f;
        for(usize textElementIndex = 0; textElementIndex < textElements.size(); ++textElementIndex)
        {
            TextElement &textElement = textElements[textElementIndex];
            if(textElement.type == TextElement::Type::EMOJI)
            {
                bool ownLineLeft = false;
                if(textElementIndex == 0)
                    ownLineLeft = true;
                else
                {
                    TextElement &prevElement = textElements[textElementIndex - 1];
                    if(prevElement.text[prevElement.text.size - 1] == '\n')
                        ownLineLeft = true;
                }
                
                bool ownLineRight = false;
                if(textElementIndex == textElements.size() - 1)
                    ownLineRight = true;
                else
                {
                    TextElement &nextElement = textElements[textElementIndex + 1];
                    if(nextElement.text[0] == '\n')
                        ownLineRight = true;
                }
                
                if(ownLineLeft && ownLineRight)
                    textElement.ownLine = true;
                
                float emojiSize = vspace * (textElement.ownLine ? EMOJI_SCALE_STANDALONE : EMOJI_SCALE_WITH_TEXT);
                
                glyphPos.x += EMOJI_PADDING;
                textElement.position.x = glyphPos.x;
                if(textElement.ownLine)
                {
                    textElement.position.y = glyphPos.y;
                    // TODO: Find a better way to do this, @totalHeight is wrong because we add emojiSize and then vspace
                    glyphPos.y += emojiSize - vspace;
                }
                else
                {
                    textElement.position.y = glyphPos.y + vspace * 0.5f - emojiSize * 0.5f;
                }
                glyphPos.x += emojiSize + EMOJI_PADDING;
                if(glyphPos.x > maxWidth)
                {
                    glyphPos.x = 0.0f;
                    glyphPos.y += vspace + lineSpacing;
                }
                
                continue;
            }
            
            usize vertexOffset = vertices.getVertexCount();
            vertices.resize(vertices.getVertexCount() + (4 * textElement.text.size));
            textElement.position = glyphPos;
            for(size_t i = 0; i < textElement.text.size; ++i)
            {
                sf::Uint32 codePoint = textElement.text[i];
                float kerning = font->getKerning(prevCodePoint, codePoint, characterSize);
                prevCodePoint = codePoint;
                glyphPos.x += kerning;
                
                switch(codePoint)
                {
                    case ' ':
                    {
                        glyphPos.x += hspace;
                        if(glyphPos.x > maxWidth * 0.5f)
                        {
                            lastSpacingWordWrapIndex = i;
                            lastSpacingAccumulatedOffset = glyphPos.x;
                        }
                        continue;
                    }
                    case '\t':
                    {
                        glyphPos.x += (hspace * TAB_WIDTH);
                        if(glyphPos.x > maxWidth * 0.5f)
                        {
                            lastSpacingWordWrapIndex = i;
                            lastSpacingAccumulatedOffset = glyphPos.x;
                        }
                        continue;
                    }
                    case '\n':
                    {
                        glyphPos.x = 0.0f;
                        glyphPos.y += vspace + lineSpacing;
                        continue;
                    }
                    case '\v':
                    {
                        glyphPos.y += (vspace * TAB_WIDTH) + lineSpacing;
                        continue;
                    }
                }
                
                const sf::Glyph &glyph = font->getGlyph(codePoint, characterSize, false);
                if(glyphPos.x + glyph.advance > maxWidth)
                {
                    // If there was a space in the text and text width is too long, then we need to word wrap at space index instead,
                    // which means we need to change the position of all vertices after the space to the current vertex
                    //printf("last spacing word wrap index: %zu\n", lastSpacingWordWrapIndex);
                    if(lastSpacingWordWrapIndex != -1)
                    {
                        for(size_t j = lastSpacingWordWrapIndex; j < i; ++j)
                        {
                            for(size_t k = 0; k < 4; ++k)
                            {
                                sf::Vector2f &vertexPos = vertices[vertexOffset + j * 4 + k].position;
                                vertexPos.x -= lastSpacingAccumulatedOffset;
                                vertexPos.y += vspace + lineSpacing;
                            }
                        }
                        
                        glyphPos.x -= lastSpacingAccumulatedOffset;
                        lastSpacingWordWrapIndex = -1;
                        lastSpacingAccumulatedOffset = 0.0f;
                    }
                    else
                        glyphPos.x = 0.0f;
                    
                    glyphPos.y += vspace + lineSpacing;
                }
                
                sf::Vector2f vertexTopLeft(glyphPos.x + glyph.bounds.left, glyphPos.y + glyph.bounds.top);
                sf::Vector2f vertexTopRight(glyphPos.x + glyph.bounds.left + glyph.bounds.width, glyphPos.y + glyph.bounds.top);
                sf::Vector2f vertexBottomLeft(glyphPos.x + glyph.bounds.left, glyphPos.y + glyph.bounds.top + glyph.bounds.height);
                sf::Vector2f vertexBottomRight(glyphPos.x + glyph.bounds.left + glyph.bounds.width, glyphPos.y + glyph.bounds.top + glyph.bounds.height);
                
                sf::Vector2f textureTopLeft(glyph.textureRect.left, glyph.textureRect.top);
                sf::Vector2f textureTopRight(glyph.textureRect.left + glyph.textureRect.width, glyph.textureRect.top);
                sf::Vector2f textureBottomLeft(glyph.textureRect.left, glyph.textureRect.top + glyph.textureRect.height);
                sf::Vector2f textureBottomRight(glyph.textureRect.left + glyph.textureRect.width, glyph.textureRect.top + glyph.textureRect.height);
                
                vertices[vertexOffset + i * 4 + 0] = { vertexTopLeft, color, textureTopLeft };
                vertices[vertexOffset + i * 4 + 1] = { vertexTopRight, color, textureTopRight };
                vertices[vertexOffset + i * 4 + 2] = { vertexBottomRight, color, textureBottomRight };
                vertices[vertexOffset + i * 4 + 3] = { vertexBottomLeft, color, textureBottomLeft };
                
                glyphPos.x += glyph.advance;
            }
        }
        totalHeight = glyphPos.y + lineSpacing + vspace;
    }
    
    void Text::draw(sf::RenderTarget &target, Cache &cache)
    {
        if(dirty)
        {
            updateGeometry();
            dirty = false;
        }
        
        float vspace = font->getLineSpacing(characterSize);
        
        sf::RenderStates states;
        sf::Vector2f pos = position;
        pos.y += floor(vspace); // Origin is at bottom left, we want it to be at top left
        
        // TODO: Do not use maxWidth here. Max width might be set to 99999 and actual text width might be 200. Text width should be calculated instead
        //sf::FloatRect targetRect(0.0f, 0.0f, maxWidth, target.getSize().y);
        //sf::FloatRect textRect(pos.x, pos.y, maxWidth, )
        //colRect.contains()
        //if(pos.x + maxWidth <= 0.0f || pos.x >= maxWidth || pos.y + totalHeight <= 0.0f || pos.y >= target.getSize().y) return;
        if(pos.y + totalHeight <= 0.0f || pos.y >= target.getSize().y) return;
        
        states.transform.translate(pos);
        states.texture = &font->getTexture(characterSize);
        target.draw(vertices, states);
        
        for(TextElement &textElement : textElements)
        {
            if(textElement.type == TextElement::Type::EMOJI)
            {
                sf::Vector2f pos = position;
                pos += textElement.position;
                pos.x = floor(pos.x);
                pos.y = floor(pos.y);
                float emojiSize = vspace * (textElement.ownLine ? EMOJI_SCALE_STANDALONE : EMOJI_SCALE_WITH_TEXT);
                sf::Vector2f size(emojiSize, emojiSize);
                
                // TODO: Optimize this (add unordered_map that takes StringViewUtf32 as key)
                auto u8Str = sf::String::fromUtf32(textElement.text.data, textElement.text.data + textElement.text.size).toUtf8();
                const std::string &utf8Str = *(std::basic_string<char>*)&u8Str;
                const ImageByUrlResult imageByUrlResult = cache.getImageByUrl(utf8Str);
                if(imageByUrlResult.type == ImageByUrlResult::Type::CACHED)
                {
                    if(imageByUrlResult.isGif)
                    {
                        auto gifSize = imageByUrlResult.gif->getSize();
                        float widthToHeightRatio = (float)gifSize.x / (float)gifSize.y;
                        
                        imageByUrlResult.gif->setPosition(pos);
                        imageByUrlResult.gif->setScale(sf::Vector2f(size.x / (float)gifSize.x * widthToHeightRatio, size.y / (float)gifSize.y));
                        imageByUrlResult.gif->draw(target);
                    }
                    else
                    {
                        auto textureSize = imageByUrlResult.texture->getSize();
                        float widthToHeightRatio = (float)textureSize.x / (float)textureSize.y;
                        
                        // TODO: Store this sprite somewhere, might not be efficient to create a new sprite object every frame
                        sf::Sprite sprite(*imageByUrlResult.texture);
                        sprite.setPosition(pos);
                        sprite.setScale(size.x / (float)textureSize.x * widthToHeightRatio, size.y / (float)textureSize.y);
                        target.draw(sprite);
                    }
                }
                else
                {
                    sf::RectangleShape rect(size);
                    rect.setFillColor(sf::Color::White);
                    rect.setPosition(pos);
                    target.draw(rect);
                }
            }
        }
    }
}