/*
 * MIT License
 *
 * Copyright (c) 2026 Mark Allyn
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

/*
 * 02_text_description.h
 * Author: Mark Allyn
 * Component: 02_text_description
 *
 * FreeType-based text renderer used by all three screen panels
 * (left description panel, scope panel, status bar).
 *
 * Usage:
 *   1. Call g_text_renderer.initialize_shaders() after GLAD is loaded.
 *   2. Call g_text_renderer.initialize_font(FONT_PATH, FONT_SIZE_NORMAL).
 *   3. Before rendering into a viewport, call set_projection(w, h).
 *   4. Call render_text() with viewport-local pixel coordinates.
 */

#pragma once

#include <string>
#include <map>
#include <glad/glad.h>
#include "data_structure_and_constants.h"
#include "settings.h"

/* Cached metrics for one loaded glyph. */
struct glyph_character {
    GLuint       texture_id; // GL_RED single-channel texture
    int          size_x;     // bitmap width in pixels
    int          size_y;     // bitmap height in pixels
    int          bearing_x;  // pixel offset from cursor to left of glyph
    int          bearing_y;  // pixel offset from cursor baseline to top of glyph
    unsigned int advance;    // horizontal advance in 1/64-pixel units
};

class TextRenderer {
public:
    TextRenderer() : vao_(0), vbo_(0), shader_program_(0) {}

    /* Compile and link 02_text_description_{vert,frag}.glsl.
     * Must be called once, after GLAD is initialised. */
    bool initialize_shaders();

    /* Load glyphs for printable ASCII (32–126) from the given font file.
     * font_size is the desired pixel height. */
    bool initialize_font(const std::string& font_path, unsigned int font_size);

    /* Render text at (x, y) in viewport-local pixel coordinates.
     * y=0 is the bottom of the current viewport.
     * scale multiplies the loaded glyph size.
     * color_r/g/b are 0.0–1.0. */
    void render_text(const std::string& text,
                     float x, float y, float scale,
                     float color_r, float color_g, float color_b);

    /* Return the rendered pixel width of text at the given scale. */
    float get_text_width(const std::string& text, float scale) const;

    /* Set the orthographic projection for a viewport of w × h pixels.
     * Call this each time glViewport changes before rendering text. */
    void set_projection(int w, int h);

    /* Release all GL resources and glyph textures. */
    void cleanup();

private:
    std::map<char, glyph_character> characters_;
    GLuint                          vao_;
    GLuint                          vbo_;
    GLuint                          shader_program_;
};

/* Global instances — shared by all panels and radar stubs.
 * g_text_renderer      : FONT_SIZE_NORMAL  (body text, controls, status bar)
 * g_text_renderer_large: FONT_SIZE_TITLE   (panel titles, scope headings) */
extern TextRenderer g_text_renderer;
extern TextRenderer g_text_renderer_large;