testsAndMisc/C/opening_learner/gui.c

#include "gui.h"
#include <SDL2/SDL.h>
#include <stdio.h>

const SDL_Color COLOR_LIGHT = {238, 238, 210, 255}; // light square (not pure white)
const SDL_Color COLOR_DARK  = {118, 150, 86, 255};  // dark square (not pure black)
const SDL_Color COLOR_GRID  = {20, 20, 20, 255};    // thick outline
const SDL_Color COLOR_SEL   = {200, 50, 50, 200};   // selection highlight
const SDL_Color COLOR_TEXT  = {10, 10, 10, 255};

static void set_color(SDL_Renderer *r, SDL_Color c)
{
    SDL_SetRenderDrawColor(r, c.r, c.g, c.b, c.a);
}

bool gui_init(Gui *g, int w, int h, const char *title)
{
    if (SDL_Init(SDL_INIT_VIDEO) != 0)
    {
        (void)fprintf(stderr, "SDL_Init error: %s\n", SDL_GetError());
        return false;
    }
    g->window = SDL_CreateWindow(title, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, w, h,
                                 SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE);
    if (!g->window)
    {
        (void)fprintf(stderr, "SDL_CreateWindow error: %s\n", SDL_GetError());
        return false;
    }
    g->renderer =
        SDL_CreateRenderer(g->window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
    if (!g->renderer)
    {
        (void)fprintf(stderr, "SDL_CreateRenderer error: %s\n", SDL_GetError());
        return false;
    }
    g->win_w   = w;
    g->win_h   = h;
    g->flipped = false;
    return true;
}

void gui_destroy(Gui *g)
{
    if (g->renderer)
        SDL_DestroyRenderer(g->renderer);
    if (g->window)
        SDL_DestroyWindow(g->window);
    SDL_Quit();
}

void gui_set_flipped(Gui *g, bool flipped) { g->flipped = flipped; }

static void draw_rect(SDL_Renderer *r, int x, int y, int w, int h, SDL_Color c)
{
    set_color(r, c);
    SDL_Rect rc = {x, y, w, h};
    SDL_RenderFillRect(r, &rc);
}

static void draw_outline(SDL_Renderer *r, SDL_Rect bounds, int thickness, SDL_Color c)
{
    set_color(r, c);
    for (int i = 0; i < thickness; i++)
    {
        SDL_Rect rc = {bounds.x + i, bounds.y + i, bounds.w - 2 * i, bounds.h - 2 * i};
        SDL_RenderDrawRect(r, &rc);
    }
}

static void draw_piece_letter(SDL_Renderer *r, SDL_Point origin, int cell_size, char piece)
{
    // Minimal: draw a filled circle/square plus an initial letter approximated with rectangles.
    // To keep dependencies minimal, no TTF. Ensure contrast: white pieces light, black pieces dark.
    SDL_Color fill  = (piece >= 'A' && piece <= 'Z') ? (SDL_Color){250, 250, 250, 255}
                                                     : (SDL_Color){30, 30, 30, 255};
    SDL_Color glyph = (piece >= 'A' && piece <= 'Z') ? (SDL_Color){30, 30, 30, 255}
                                                     : (SDL_Color){240, 240, 240, 255};
    // Base disk
    int disk_offset = (int)(cell_size * 0.15f);
    int disk_size   = (int)(cell_size * 0.7f);
    draw_rect(r, origin.x + disk_offset, origin.y + disk_offset, disk_size, disk_size, fill);
    // Glyph: draw a simple letter-like mark
    set_color(r, glyph);
    // vertical bar
    SDL_Rect bar1 = {origin.x + cell_size / 2 - cell_size / 16, origin.y + cell_size / 3,
                     cell_size / 8, cell_size / 3};
    SDL_RenderFillRect(r, &bar1);
    // top bar
    SDL_Rect bar2 = {origin.x + cell_size / 3, origin.y + cell_size / 3 - cell_size / 10,
                     cell_size / 3, cell_size / 10};
    SDL_RenderFillRect(r, &bar2);
}

void gui_draw(Gui *g, const char board[64], const GuiSelection *sel, const char *status_line)
{
    SDL_GetWindowSize(g->window, &g->win_w, &g->win_h);

    set_color(g->renderer, (SDL_Color){35, 35, 35, 255});
    SDL_RenderClear(g->renderer);

    int size = (g->win_w < g->win_h ? g->win_w : g->win_h) - 40; // margins
    if (size < 200)
        size = 200;
    int cell = size / 8;
    size     = cell * 8;
    int ox   = (g->win_w - size) / 2;
    int oy   = (g->win_h - size) / 2;

    // Board outline (thick)
    SDL_Rect board_bounds = {ox - 6, oy - 6, size + 12, size + 12};
    draw_outline(g->renderer, board_bounds, 6, COLOR_GRID);

    // Squares
    for (int r = 0; r < 8; r++)
    {
        for (int f = 0; f < 8; f++)
        {
            int       idx    = g->flipped ? (63 - (r * 8 + f)) : (r * 8 + f);
            SDL_Color c      = ((r + f) & 1) ? COLOR_DARK : COLOR_LIGHT;
            int       cell_x = ox + f * cell;
            int       cell_y = oy + r * cell;
            draw_rect(g->renderer, cell_x, cell_y, cell, cell, c);

            char piece = board[idx];
            if (piece != '.' && piece != '\0')
            {
                SDL_Point origin = {cell_x, cell_y};
                draw_piece_letter(g->renderer, origin, cell, piece);
            }
        }
    }

    // Selection overlay
    if (sel && sel->clicked && sel->from_sq >= 0)
    {
        int      s          = sel->from_sq;
        int      rr         = g->flipped ? 7 - (s / 8) : (s / 8);
        int      ff         = g->flipped ? 7 - (s % 8) : (s % 8);
        SDL_Rect sel_bounds = {ox + ff * cell + 2, oy + rr * cell + 2, cell - 4, cell - 4};
        draw_outline(g->renderer, sel_bounds, 3, COLOR_SEL);
    }

    // Status strip
    SDL_Rect status_bounds = {10, g->win_h - 40, g->win_w - 20, 30};
    draw_outline(g->renderer, status_bounds, 2, COLOR_GRID);
    // Without TTF, we can't render text; draw a minimal indicator bar to signal state.
    // If status_line indicates success/failure, alter color.
    SDL_Color bar = {80, 120, 200, 255};
    if (status_line && status_line[0])
    {
        if (SDL_strstr(status_line, "Correct"))
            bar = (SDL_Color){80, 200, 120, 255};
        else if (SDL_strstr(status_line, "Wrong"))
            bar = (SDL_Color){200, 80, 80, 255};
    }
    draw_rect(g->renderer, 12, g->win_h - 38, g->win_w - 24, 26, bar);

    SDL_RenderPresent(g->renderer);
}

int gui_coord_to_sq(Gui *g, int x, int y)
{
    int w, h;
    SDL_GetWindowSize(g->window, &w, &h);
    int size = (w < h ? w : h) - 40;
    if (size < 200)
        size = 200;
    int cell = size / 8;
    size     = cell * 8;
    int ox   = (w - size) / 2;
    int oy   = (h - size) / 2;
    if (x < ox || y < oy || x >= ox + size || y >= oy + size)
        return -1;
    int f  = (x - ox) / cell;
    int r  = (y - oy) / cell;
    int sq = r * 8 + f;
    if (g->flipped)
        sq = 63 - sq;
    return sq;
}

bool gui_poll_move(Gui *g, GuiSelection *sel, bool *quit_requested, int *key_out)
{
    SDL_Event e;
    bool      updated = false;
    if (key_out)
        *key_out = 0;
    while (SDL_PollEvent(&e))
    {
        if (e.type == SDL_QUIT)
        {
            if (quit_requested)
                *quit_requested = true;
        }
        else if (e.type == SDL_WINDOWEVENT && e.window.event == SDL_WINDOWEVENT_SIZE_CHANGED)
        {
            updated = true;
        }
        else if (e.type == SDL_MOUSEBUTTONDOWN && e.button.button == SDL_BUTTON_LEFT)
        {
            int sq = gui_coord_to_sq(g, e.button.x, e.button.y);
            if (sq >= 0)
            {
                if (!sel->clicked)
                {
                    sel->from_sq = sq;
                    sel->to_sq   = -1;
                    sel->clicked = true;
                }
                else
                {
                    sel->to_sq = sq;
                    updated    = true;
                }
            }
        }
        else if (e.type == SDL_KEYDOWN)
        {
            if (e.key.keysym.sym == SDLK_ESCAPE)
            {
                sel->clicked = false;
                sel->from_sq = sel->to_sq = -1;
                updated                   = true;
            }
            if (key_out)
                *key_out = e.key.keysym.sym;
        }
    }
    return updated;
}