#include "text.h"

#include "renderer.h"

#include <assert.h>

#define NELEMS(arr) (sizeof(arr) / sizeof(arr[0]))

#define MAX_LINES 2

#define TEXT_HEIGHT 8
#define TEXT_SCALE 0.025
#define LETTER_WIDTH 3
#define SPACE_WIDTH 1

typedef struct {
	unsigned line_count;
	unsigned line_lens[MAX_LINES];
	vec2_t lines[MAX_LINES][MAX_VERTS];
} glyph_t;

static const mat3_t text_transform = {
	{ TEXT_SCALE, 0, 0 },
	{ 0, TEXT_SCALE, 0 },
	{ 0, 0, 1 },
};

static const glyph_t font[] = {
	['A'] = {
		.line_count = 2,
		.line_lens = { 3, 2 },
		.lines = {
			{ { -1, -4 }, { 0, 4 }, { 1, -4 } },
			{ { -0.75, -2 }, { 0.75, -2 } },
		},
	},
	['C'] = {
		.line_count = 1,
		.line_lens = { 4 },
		.lines = {
			{ { 1, 4 }, { -1, 4 }, { -1, -4 }, { 1, -4 } },
		},
	},
	['E'] = {
		.line_count = 2,
		.line_lens = { 4, 2 },
		.lines = {
			{ { 1, 4 }, { -1, 4 }, { -1, -4 }, { 1, -4 } },
			{ { -1, -2 }, { 0, -2 } },
		},
	},
	['G'] = {
		.line_count = 1,
		.line_lens = { 5 },
		.lines = {
			{ { 1, 4 }, { -1, 4 }, { -1, -4 }, { 1, -4 }, { 1, -2 } },
		},
	},
	['L'] = {
		.line_count = 1,
		.line_lens = { 3 },
		.lines = {
			{ { -1, 4 }, { -1, -4 }, { 1, -4 } },
		},
	},
	['M'] = {
		.line_count = 1,
		.line_lens = { 5 },
		.lines = {
			{ { -1, -4 }, { -1, 4 }, { 0, -4 }, { 1, 4 }, { 1, -4 } },
		},
	},
	['O'] = {
		.line_count = 1,
		.line_lens = { 5 },
		.lines = {
			{ { -1, 4 }, { -1, -4 }, { 1, -4 }, { 1, 4 }, { -1, 4 } },
		},
	},
	['R'] = {
		.line_count = 1,
		.line_lens = { 6 },
		.lines = {
			{
				{ -1, -4 }, { -1, 4 }, { 1, 4 },
				{ 1, -2 }, { -1, -2 }, { 1, -4 },
			},
		},
	},
	['V'] = {
		.line_count = 1,
		.line_lens = { 3 },
		.lines = {
			{ { -1, 4 }, { 0, -4 }, { 1, 4 } },
		},
	},
};

void text_draw(const char *s)
{
	int width = 0;
	for (const char *p = s; *p != '\0'; ++p)
		width += *p == ' ' ? SPACE_WIDTH : LETTER_WIDTH;
	--width;

	const vec2_t bg_size = {
		.x = TEXT_SCALE * (width + 2),
		.y = TEXT_SCALE * (TEXT_HEIGHT + 2),
	};
	renderer_clear_rect((vec2_t) { 0, 0 }, bg_size);

	int x = -width / 2 + 1;
	for (const char *p = s; *p != '\0'; ++p) {
		if (*p == ' ') {
			x += SPACE_WIDTH;
		} else {
			const unsigned c = (unsigned)*p;
			assert(c < NELEMS(font) && font[c].line_count != 0);
			const glyph_t *g = font + c;

			const vec2_t t = { .x = x };
			const mat3_t m
			    = mat3_mul_mat3(text_transform, mat3_translation(t));

			for (unsigned i = 0; i < g->line_count; ++i)
				renderer_draw(g->lines[i], g->line_lens[i], m, false);

			x += LETTER_WIDTH;
		}
	}
}