#pragma once
/*
 *  Copyright (C) 2024  Brett Terpstra
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#ifndef BLT_WITH_GRAPHICS_FONT_RENDERER_H
#define BLT_WITH_GRAPHICS_FONT_RENDERER_H

#include <blt/gfx/font/font.h>
#include <blt/gfx/texture.h>
#include <blt/gfx/shader.h>
#include <blt/gfx/model.h>
#include <blt/std/hashmap.h>
#include <blt/std/binary_tree.h>

namespace blt::gfx
{
    
    class font_texture_atlas : public texture_gl2D
    {
        public:
            struct bounded_t
            {
                font::glyph_t glyph;
                // starting point
                blt::vec2ui min;
                // ending point of the glyph, inside texture atlas
                blt::vec2ui max;
            };
            struct added_font_results_t
            {
                blt::u64 last_inserted_index;
                blt::u64 min_index_used;
                blt::u64 max_index_used;
            };
        public:
            explicit font_texture_atlas(blt::i32 dimensions);
            
            added_font_results_t add_font(const font::font_file_t& file);
            
            added_font_results_t add_font(const font::font_file_t& file, blt::u64 start);
            
            bounded_t& get_glyph(blt::u64 c)
            { return glyphs.at(c); }
            
            [[nodiscard]] const bounded_t& get_glyph(blt::u64 c) const
            { return glyphs.at(c); }
        
        private:
            blt::hashmap_t<blt::u64, bounded_t> glyphs;
            blt::u32 used_width = 0;
            blt::u32 used_height = 0;
    };
    
    class font_generator_t
    {
        public:
            struct bounded_font_t
            {
                std::unique_ptr<font_texture_atlas> atlas;
                float min_size, max_size;
                blt::u64 min_char, max_char;
                
                bounded_font_t(std::unique_ptr<font_texture_atlas> atlas, float minSize, float maxSize, u64 minChar, u64 maxChar):
                        atlas(std::move(atlas)), min_size(minSize), max_size(maxSize), min_char(minChar), max_char(maxChar)
                {}
            };
        
        public:
            explicit font_generator_t(blt::i32 dimensions, const std::vector<float>& sizes_to_generate);
            
            void add_font(const font::font_file_t& file);
            
            inline font_texture_atlas& get_texture(float size, blt::u64 c)
            {
                for (auto& atlas : atlases)
                {
                    if (!(size >= atlas.min_size && size <= atlas.max_size))
                        continue;
                    if (atlas.min_char > c && atlas.max_char < c)
                        return *atlas.atlas;
                }
                throw std::runtime_error("Character not found inside atlases at this size");
            }
        
        private:
            blt::i32 dimensions;
            std::vector<bounded_font_t> atlases;
            std::vector<float> sizes_to_generate;
    };
    
    class font_renderer_t
    {
        public:
            struct compiled_text_t
            {
                std::shared_ptr<vertex_array_t> vao;
                blt::size_t render_count;
            };
        public:
            explicit font_renderer_t();
            
            void create(const std::vector<float>& generated_font_sizes, blt::i32 dimensions = 0);
            
            void cleanup();
            
            void add_font(const font::font_file_t& file)
            {
                generator->add_font(file);
            }
            
            compiled_text_t create_text(std::string_view str);
        
        private:
            std::unique_ptr<font_generator_t> generator;
            std::unique_ptr<shader_t> font_shader;
    };
    
}

#endif //BLT_WITH_GRAPHICS_FONT_RENDERER_H