// nooncraft.render: Grid-like text rendering
//
// Owing to the CPC constraint, the entire rendering system for this game is
// just text with a single font. We make two adjustments on the grid model:
//
// 1. We group rows and columns by pairs, so that the row/column spacing
//    alternates between 1 and 3. This allows blocks to be represented by
//    "clusters" of 4 characters.
// 2. To keep text natural, we provide a text function which forces column
//    spacing to 2, offsetting every other character by 1 pixel. Rows remain
//    irregularly spaced.
//---

#pragma once

using Glyph = char;

/* Non-ASCII glyphs */
enum {
    GLYPH_FOUR_DOT          =  1,   /* U+2058 FOUR DOT PUNCTUATION */
    GLYPH_MIDDLE_DOT        =  2,   /* U+00B7 MIDDLE DOT */
    GLYPH_PARALLEL_TO       =  3,   /* U+2225 PARALLEL TO */
    GLYPH_CURRENCY_SIGN     =  4,   /* U+00A4 CURRENCY SIGN */
    GLYPH_NORTH_EAST_ARROW  =  5,   /* U+2197 NORTH EAST ARROW */
    GLYPH_RIGHT_GUILLEMET   =  6,   /* U+00BB RIGHT GUILLEMET */
    GLYPH_DOWN_ARROW        =  7,   /* U+2193 DOWNARDS ARROW */
    GLYPH_I_CIRCUMFLEX      =  8,   /* U+00EE SMALL LATIN I WITH CIRCUMFLEX */
    GLYPH_INTEGRAL          =  9,   /* U+222B INTEGRAL */
    GLYPH_SMALL_SQUARE      = 10,   /* U+25AB WHITE SMALL SQUARE */
    GLYPH_STAR              = 11,   /* U+2605 BLACK STAR */
    GLYPH_CIRCLE            = 12,   /* U+25CF BLACK CIRCLE */
    GLYPH_UP_ARROW_BAR      = 13,   /* U+21A5 UPWARDS ARROW FROM BAR */
    GLYPH_CAPITAL_LAMBDA    = 14,   /* U+039B GREEK CAPITAL LETTER LAMBDA */
    GLYPH_DEGREE_UNDERLINE  = 15,   /* U+00B0 U+0331 */
    GLYPH_OPLUS             = 16,   /* U+2295 CIRCLED PLUS */
};

/* A cluster of 4 glyphs. Can be conversion-constructed from a multi-byte
   character literal like 'AXE '. */
struct GlyphCluster
{
    GlyphCluster(): glyphs {0,0,0,0} {}

    GlyphCluster(Glyph g1, Glyph g2, Glyph g3, Glyph g4):
        glyphs {g1, g2, g3, g4} {}

    GlyphCluster(int mbliteral) {
        this->glyphs[0] = mbliteral >> 24;
        this->glyphs[1] = (mbliteral >> 16) & 0xff;
        this->glyphs[2] = (mbliteral >> 8) & 0xff;
        this->glyphs[3] = mbliteral & 0xff;
    }

    GlyphCluster applyOver(GlyphCluster const &other) {
        return GlyphCluster(
            this->glyphs[0] ? this->glyphs[0] : other.glyphs[0],
            this->glyphs[1] ? this->glyphs[1] : other.glyphs[1],
            this->glyphs[2] ? this->glyphs[2] : other.glyphs[2],
            this->glyphs[3] ? this->glyphs[3] : other.glyphs[3]);
    }

    Glyph glyphs[4];
};

/* Enable or disable night mode (black-on-white). */
void renderSetNight(bool night);
/* Clear the screen. */
void renderClear(void);
/* Update the screen. */
void renderUpdate(void);

/* Render a single character with text alignment (2-pixel column spacing).
   The position (x,y) is counted in characters units with (0,0) top-left. */
void renderGlyph(int x, int y, Glyph g);

/* Render a 2x2 cluster of 4 characters. The position (x,y) should be even on
   both axes. */
void renderCluster(int x, int y, GlyphCluster c);

/* Render a string with text alignment. */
void renderText(int x, int y, char const *text);
/* Same with printf() formatting. */
void renderFormat(int x, int y, char const *fmt, ...);