#pragma once

#include <SFML/Graphics/VertexArray.hpp>
#include <SFML/System/String.hpp>
#include <SFML/System/Clock.hpp>
#include <vector>
#include "types.hpp"
#include <assert.h>

namespace sf {
    class Font;
    class Event;
    class RenderTarget;
}

namespace QuickMedia
{
    struct StringViewUtf32 {
        const u32 *data;
        size_t size;

        StringViewUtf32() : data(nullptr), size(0) {}
        StringViewUtf32(const u32 *data, usize size) : data(data), size(size) {}

        size_t find(const StringViewUtf32 &other, size_t offset = 0) const;

        u32 operator [] (usize index) const {
            assert(index < size);
            return data[index];
        }
    };

    struct TextElement
    {
        enum class Type
        {
            TEXT
        };

        enum class TextType {
            LATIN,
            CJK,
            EMOJI
        };
        
        TextElement() {}
        TextElement(const StringViewUtf32 &_text, Type _type) : text(_text), type(_type), text_type(TextType::LATIN) {}
        
        StringViewUtf32 text;
        sf::Vector2f position;
        Type type;
        //bool ownLine; // Currently only used for emoji, to make emoji bigger when it's the only thing on a line
        TextType text_type;
    };

    struct VertexRef {
        int vertices_index;     // index to |vertices| VertexArray
        int index;              // index within vertices[vertices_index]
        int line;
        sf::Uint32 codepoint;
    };
    
    class Text
    {
    public:
        Text(bool bold_font);
        Text(sf::String str, bool bold_font, unsigned int characterSize, float maxWidth);
        
        void setString(sf::String str);
        const sf::String& getString() const;
        void appendText(sf::String str);
        
        void setPosition(float x, float y);
        void setPosition(const sf::Vector2f &position);
        sf::Vector2f getPosition() const;
        
        void setMaxWidth(float maxWidth);
        float getMaxWidth() const;
        
        void setCharacterSize(unsigned int characterSize);
        unsigned int getCharacterSize() const;

        
        void setFillColor(sf::Color color);
        void setLineSpacing(float lineSpacing);
        void setCharacterSpacing(float characterSpacing);
        void setEditable(bool editable);
        bool isEditable() const;
        // Note: only call after initial updateGeometry or draw. TODO: Automatically do this internally
        void moveCaretToEnd();

        // Note: won't update until @draw is called
        float getWidth() const;
        
        // Note: won't update until @draw is called
        float getHeight() const;
        
        void processEvent(const sf::Event &event);
        
        // Performs culling. @updateGeometry is called even if text is not visible if text is dirty, because updateGeometry might change the dimension of the text and make is visible.
        // Returns true if text was drawn on screen (if text is within window borders)
        bool draw(sf::RenderTarget &target);

        void updateGeometry(bool update_even_if_not_dirty = false);
    private:
        enum class CaretMoveDirection : u8
        {
            NONE,
            UP,
            DOWN,
            HOME,
            END,
            LEFT,
            RIGHT,
            LEFT_WORD,
            RIGHT_WORD
        };

        void updateCaret();
        int getStartOfLine(int startIndex) const;
        int getEndOfLine(int startIndex) const;
        int getStartOfWord(int startIndex) const;
        int getEndOfWord(int startIndex) const;
        
        int getPreviousLineClosestPosition(int startIndex) const;
        int getNextLineClosestPosition(int startIndex) const;

        void splitTextByFont();

        float get_text_quad_left_side(const VertexRef &vertex_ref) const;
        float get_text_quad_right_side(const VertexRef &vertex_ref) const;
        // If the index is past the end, then the caret offset is the right side of the last character, rather than the left side
        float get_caret_offset_by_caret_index(int index) const;
        VertexRef& get_vertex_ref_clamp(int index);
        // Takes into consideration if index is the last vertex and the last vertex is a newline, then it should be on its own line
        int get_vertex_line(int index) const;
        sf::Uint32 get_vertex_codepoint(int index) const;
    private:
        sf::String str; // TODO: Remove this for non-editable text??? also replace with std::string? then we get more efficient editing of text
        const bool bold_font;
        unsigned int characterSize;
        sf::VertexArray vertices[3];
        float maxWidth;
        sf::Vector2f position;
        sf::Color color;
        sf::Color urlColor;
        bool dirty;
        bool dirtyText;
        bool dirtyCaret;
        bool editable;
        CaretMoveDirection caretMoveDirection;
        sf::FloatRect boundingBox;
        int num_lines;
        float lineSpacing;
        float characterSpacing;
        std::vector<TextElement> textElements;
        
        int caretIndex;
        float caret_offset_x;
        sf::Vector2f caretPosition;
        sf::Vector2u renderTargetSize;

        std::vector<VertexRef> vertices_linear; // TODO: Use textElements instead
    };
}