/**
 * @file graphics_verbs.c
 * @brief Tests the group G verbs against the recording mock backend.
 *
 * These verbs emit nothing a golden file can compare, so the assertions are on
 * the call log: what reached the device, in what order, with what geometry and
 * what color. Running a real BASIC line rather than calling the handler directly
 * is deliberate -- it exercises the dispatch-table row and the parse handler as
 * well, which is where an added verb is most likely to be wrong.
 */

#include <string.h>

#include <akbasic/error.h>
#include <akbasic/graphics.h>
#include <akbasic/runtime.h>

#include "harness.h"
#include "mockdevice.h"
#include "testutil.h"

/** @brief Bring up a runtime with the mock devices attached and a program loaded. */
static akerr_ErrorContext AKERR_NOIGNORE *run_program(const char *source)
{
    PREPARE_ERROR(errctx);

    PASS(errctx, harness_start(NULL));
    mock_devices_init();
    PASS(errctx, akbasic_runtime_set_devices(&HARNESS_RUNTIME, &MOCK_GRAPHICS,
					     &MOCK_AUDIO, &MOCK_INPUT, NULL));
    PASS(errctx, akbasic_runtime_load(&HARNESS_RUNTIME, source));
    PASS(errctx, akbasic_runtime_start(&HARNESS_RUNTIME, AKBASIC_MODE_RUN));
    PASS(errctx, akbasic_runtime_run(&HARNESS_RUNTIME, 0));
    SUCCEED_RETURN(errctx);
}

/** @brief The white of palette index 2, which most of these draw with. */
#define WHITE "#ffffff"
/** @brief The red of palette index 3. */
#define RED "#883932"

/**
 * @brief A single DRAW coordinate pair plots a point; two or more draw a
 *        polyline; none at all plots wherever LOCATE left the cursor.
 */
static void test_draw(void)
{
    TEST_REQUIRE_OK(run_program("10 DRAW 1, 10, 20\n"));
    TEST_REQUIRE_STR(MOCK.log, "point 10.0,20.0 " WHITE "\n");
    harness_stop();

    TEST_REQUIRE_OK(run_program("10 DRAW 1, 0, 0 TO 10, 0 TO 10, 10\n"));
    TEST_REQUIRE_STR(MOCK.log,
		     "line 0.0,0.0-10.0,0.0 " WHITE "\n"
		     "line 10.0,0.0-10.0,10.0 " WHITE "\n");
    harness_stop();

    /* LOCATE moves the pixel cursor; a bare DRAW plots it. */
    TEST_REQUIRE_OK(run_program("10 LOCATE 33, 44\n20 DRAW 1\n"));
    TEST_REQUIRE_STR(MOCK.log, "point 33.0,44.0 " WHITE "\n");
    harness_stop();

    /* An odd number of coordinates is a typo, not half a line. */
    TEST_REQUIRE_OK(harness_start(NULL));
    mock_devices_init();
    TEST_REQUIRE_OK(akbasic_runtime_set_devices(&HARNESS_RUNTIME, &MOCK_GRAPHICS, NULL, NULL, NULL));
    TEST_REQUIRE_OK(akbasic_runtime_load(&HARNESS_RUNTIME, "10 DRAW 1, 5\n"));
    TEST_REQUIRE_OK(akbasic_runtime_start(&HARNESS_RUNTIME, AKBASIC_MODE_RUN));
    TEST_REQUIRE_OK(akbasic_runtime_run(&HARNESS_RUNTIME, 0));
    TEST_REQUIRE(strstr(HARNESS_OUTPUT, "X,Y pairs") != NULL,
		 "an odd coordinate count should be refused, got \"%s\"", HARNESS_OUTPUT);
    harness_stop();
}

/** @brief COLOR rebinds a source, and every drawing verb follows the rebinding. */
static void test_color(void)
{
    TEST_REQUIRE_OK(run_program("10 COLOR 1, 3\n20 DRAW 1, 1, 1\n"));
    TEST_REQUIRE_STR(MOCK.log, "point 1.0,1.0 " RED "\n");
    harness_stop();

    /* Both arguments are range-checked, and BASIC counts colors from 1. */
    TEST_REQUIRE_OK(run_program("10 COLOR 9, 3\n"));
    TEST_REQUIRE(strstr(HARNESS_OUTPUT, "COLOR source 9") != NULL,
		 "an out-of-range source should be refused, got \"%s\"", HARNESS_OUTPUT);
    harness_stop();

    TEST_REQUIRE_OK(run_program("10 COLOR 1, 0\n"));
    TEST_REQUIRE(strstr(HARNESS_OUTPUT, "COLOR 0") != NULL,
		 "color 0 should be refused, got \"%s\"", HARNESS_OUTPUT);
    harness_stop();
}

/** @brief An unrotated BOX is a rectangle; a rotated one is four lines. */
static void test_box(void)
{
    TEST_REQUIRE_OK(run_program("10 BOX 1, 0, 0, 10, 10\n"));
    TEST_REQUIRE_STR(MOCK.log, "rect 0.0,0.0-10.0,10.0 " WHITE "\n");
    harness_stop();

    /*
     * Rotated 90 degrees about its own center, a square lands back on itself --
     * same four edges, walked from a different starting corner. That is the
     * assertion worth making, because it pins the rotation *origin*: rotating
     * about the coordinate origin instead of the box's center would put the
     * square somewhere else entirely, and rotating about a corner would tilt it.
     *
     * The -0.0 is real and harmless: cos(pi/2) is not exactly zero, so one
     * coordinate lands on negative zero, which compares equal to zero everywhere
     * it matters and only shows up because the mock prints it.
     */
    TEST_REQUIRE_OK(run_program("10 BOX 1, 0, 0, 10, 10, 90\n"));
    TEST_REQUIRE_STR(MOCK.log,
		     "line 10.0,-0.0-10.0,10.0 " WHITE "\n"
		     "line 10.0,10.0-0.0,10.0 " WHITE "\n"
		     "line 0.0,10.0-0.0,0.0 " WHITE "\n"
		     "line 0.0,0.0-10.0,-0.0 " WHITE "\n");
    harness_stop();
}

/** @brief CIRCLE is a polygon of arc-increment segments, and closes. */
static void test_circle(void)
{
    int segments = 0;
    const char *cursor = NULL;

    /* 360 degrees at 90 per segment is four lines, whatever the radius. */
    TEST_REQUIRE_OK(run_program("10 CIRCLE 1, 50, 50, 10, 10, 0, 360, 0, 90\n"));
    for ( cursor = MOCK.log; (cursor = strstr(cursor, "line ")) != NULL; cursor += 5 ) {
	segments += 1;
    }
    TEST_REQUIRE_INT(segments, 4);
    /* The first vertex is directly above the center, as BASIC 7.0 starts it. */
    TEST_REQUIRE(strncmp(MOCK.log, "line 50.0,40.0-", 15) == 0,
		 "CIRCLE should start at the top of the circle, got \"%.30s\"", MOCK.log);
    harness_stop();

    /* A negative radius and a zero increment are both refusals, not loops. */
    TEST_REQUIRE_OK(run_program("10 CIRCLE 1, 50, 50, -5\n"));
    TEST_REQUIRE(strstr(HARNESS_OUTPUT, "radius") != NULL,
		 "a negative radius should be refused, got \"%s\"", HARNESS_OUTPUT);
    harness_stop();

    TEST_REQUIRE_OK(run_program("10 CIRCLE 1, 50, 50, 10, 10, 0, 360, 0, 0\n"));
    TEST_REQUIRE(strstr(HARNESS_OUTPUT, "increment") != NULL,
		 "a zero arc increment should be refused, got \"%s\"", HARNESS_OUTPUT);
    harness_stop();
}

/**
 * @brief PAINT reports a partial fill rather than letting it pass as success.
 *
 * The device gives up when its span stack runs out, having filled some of the
 * region. A program that cannot tell that happened has no way to recover, so the
 * error is the feature.
 */
static void test_paint(void)
{
    TEST_REQUIRE_OK(run_program("10 PAINT 1, 5, 5\n"));
    TEST_REQUIRE_STR(MOCK.log, "paint 5,5 " WHITE "\n");
    harness_stop();

    TEST_REQUIRE_OK(harness_start(NULL));
    mock_devices_init();
    MOCK.paint_exhausts = true;
    TEST_REQUIRE_OK(akbasic_runtime_set_devices(&HARNESS_RUNTIME, &MOCK_GRAPHICS, NULL, NULL, NULL));
    TEST_REQUIRE_OK(akbasic_runtime_load(&HARNESS_RUNTIME, "10 PAINT 1, 5, 5\n"));
    TEST_REQUIRE_OK(akbasic_runtime_start(&HARNESS_RUNTIME, AKBASIC_MODE_RUN));
    TEST_REQUIRE_OK(akbasic_runtime_run(&HARNESS_RUNTIME, 0));
    TEST_REQUIRE(strstr(HARNESS_OUTPUT, "only part of the region") != NULL,
		 "a partial fill should be reported, got \"%s\"", HARNESS_OUTPUT);
    harness_stop();
}

/**
 * @brief SCALE maps user coordinates onto the device's own size, and only then.
 *
 * The mock reports 640x400, which is what every scaled expectation below is
 * against. If the interpreter ever stops asking the device and goes back to the
 * 320x200 constants, every one of them is out by a factor of two -- which is
 * the reason the mock's size is not 320x200.
 */
static void test_scale(void)
{
    /* Off by default: a coordinate is a device pixel and passes through
       untouched, which is what puts the whole of the host's window in reach. */
    TEST_REQUIRE_OK(run_program("10 DRAW 1, 160, 100\n"));
    TEST_REQUIRE_STR(MOCK.log, "point 160.0,100.0 " WHITE "\n");
    harness_stop();

    /* A coordinate past the old 320x200 ceiling is not clamped, refused, or
       wrapped. This is item 9 in one assertion. */
    TEST_REQUIRE_OK(run_program("10 DRAW 1, 639, 399\n"));
    TEST_REQUIRE_STR(MOCK.log, "point 639.0,399.0 " WHITE "\n");
    harness_stop();

    /* On, with the 7.0 default maxima: the far corner of the user space is the
       far corner of the *device*, not of a 320x200 screen inside it -- and it
       is the last pixel, 639, rather than one past it. */
    TEST_REQUIRE_OK(run_program("10 SCALE 1\n20 DRAW 1, 1023, 1023\n"));
    TEST_REQUIRE_STR(MOCK.log, "point 639.0,399.0 " WHITE "\n");
    harness_stop();

    /* And a C128 listing fills the window by declaring the space it was
       written for, which is the migration path for every one of them. */
    TEST_REQUIRE_OK(run_program("10 SCALE 1, 319, 199\n20 DRAW 1, 319, 199\n"));
    TEST_REQUIRE_STR(MOCK.log, "point 639.0,399.0 " WHITE "\n");
    harness_stop();

    TEST_REQUIRE_OK(run_program("10 SCALE 1, 0, 400\n"));
    TEST_REQUIRE(strstr(HARNESS_OUTPUT, "positive") != NULL,
		 "a zero SCALE maximum should be refused, got \"%s\"", HARNESS_OUTPUT);
    harness_stop();
}

/**
 * @brief A backend that will not say how big it is gets the 320x200 fallback.
 *
 * `size` is the record's one optional entry point, so a host that filled a
 * backend in before it existed has to keep working -- and what it gets is the
 * space a C128 listing was written for rather than a division by zero.
 */
static void test_scale_without_a_size(void)
{
    TEST_REQUIRE_OK(harness_start(NULL));
    mock_devices_init();
    MOCK_GRAPHICS.size = NULL;
    TEST_REQUIRE_OK(akbasic_runtime_set_devices(&HARNESS_RUNTIME, &MOCK_GRAPHICS, NULL, NULL, NULL));
    TEST_REQUIRE_OK(akbasic_runtime_load(&HARNESS_RUNTIME, "10 SCALE 1\n20 DRAW 1, 1023, 1023\n"));
    TEST_REQUIRE_OK(akbasic_runtime_start(&HARNESS_RUNTIME, AKBASIC_MODE_RUN));
    TEST_REQUIRE_OK(akbasic_runtime_run(&HARNESS_RUNTIME, 0));
    TEST_REQUIRE_STR(MOCK.log, "point 319.0,199.0 " WHITE "\n");
    harness_stop();

    /*
     * A device reporting nothing useful -- an SDL window mid-resize measures
     * zero -- is not an error and must not become the space, because dividing
     * by it would send every scaled coordinate to infinity.
     */
    TEST_REQUIRE_OK(harness_start(NULL));
    mock_devices_init();
    MOCK.devwidth = 0;
    MOCK.devheight = 0;
    TEST_REQUIRE_OK(akbasic_runtime_set_devices(&HARNESS_RUNTIME, &MOCK_GRAPHICS, NULL, NULL, NULL));
    TEST_REQUIRE_OK(akbasic_runtime_load(&HARNESS_RUNTIME, "10 SCALE 1\n20 DRAW 1, 1023, 1023\n"));
    TEST_REQUIRE_OK(akbasic_runtime_start(&HARNESS_RUNTIME, AKBASIC_MODE_RUN));
    TEST_REQUIRE_OK(akbasic_runtime_run(&HARNESS_RUNTIME, 0));
    TEST_REQUIRE_STR(MOCK.log, "point 319.0,199.0 " WHITE "\n");
    harness_stop();
}

/** @brief RGR answers the mode, the width and the height, and refuses the rest. */
static void test_rgr(void)
{
    TEST_REQUIRE_OK(run_program("10 GRAPHIC 3\n20 PRINT RGR(0)\n"));
    TEST_REQUIRE_STR(HARNESS_OUTPUT, "3\n");
    harness_stop();

    TEST_REQUIRE_OK(run_program("10 PRINT RGR(1)\n20 PRINT RGR(2)\n"));
    TEST_REQUIRE_STR(HARNESS_OUTPUT, "640\n400\n");
    harness_stop();

    /* The whole point of asking: a program can draw to the far corner without
       knowing in advance what size window the host opened. */
    TEST_REQUIRE_OK(run_program("10 DRAW 1, RGR(1) - 1, RGR(2) - 1\n"));
    TEST_REQUIRE_STR(MOCK.log, "point 639.0,399.0 " WHITE "\n");
    harness_stop();

    TEST_REQUIRE_OK(run_program("10 PRINT RGR(5)\n"));
    TEST_REQUIRE(strstr(HARNESS_OUTPUT, "outside 0..4") != NULL,
		 "RGR(5) should be refused, got \"%s\"", HARNESS_OUTPUT);
    harness_stop();

    /*
     * 3 and 4 are the character cell, and they come from the *sink* rather than
     * the graphics device -- a grid belongs to a text device. The harness sink
     * is stdio and has none, so what a device-less build can assert is the
     * refusal; tests/console_verbs.c drives the answers through a stand-in sink
     * that does have a grid.
     */
    TEST_REQUIRE_OK(run_program("10 PRINT RGR(3)\n"));
    TEST_REQUIRE(strstr(HARNESS_OUTPUT, "text device with a character grid") != NULL,
		 "RGR(3) against a grid-less sink should refuse by name, got \"%s\"",
		 HARNESS_OUTPUT);
    harness_stop();

    TEST_REQUIRE_OK(run_program("10 PRINT RGR(4)\n"));
    TEST_REQUIRE(strstr(HARNESS_OUTPUT, "text device with a character grid") != NULL,
		 "RGR(4) against a grid-less sink should refuse by name, got \"%s\"",
		 HARNESS_OUTPUT);
    harness_stop();

    /*
     * The mode is state and answers with no device; a size is not, and asking
     * for one when there is no screen is a program bug worth reporting.
     */
    TEST_REQUIRE_OK(harness_start(NULL));
    TEST_REQUIRE_OK(akbasic_runtime_load(&HARNESS_RUNTIME, "10 PRINT RGR(0)\n"));
    TEST_REQUIRE_OK(akbasic_runtime_start(&HARNESS_RUNTIME, AKBASIC_MODE_RUN));
    TEST_REQUIRE_OK(akbasic_runtime_run(&HARNESS_RUNTIME, 0));
    TEST_REQUIRE_STR(HARNESS_OUTPUT, "0\n");
    harness_stop();

    TEST_REQUIRE_OK(harness_start(NULL));
    TEST_REQUIRE_OK(akbasic_runtime_load(&HARNESS_RUNTIME, "10 PRINT RGR(1)\n"));
    TEST_REQUIRE_OK(akbasic_runtime_start(&HARNESS_RUNTIME, AKBASIC_MODE_RUN));
    TEST_REQUIRE_OK(akbasic_runtime_run(&HARNESS_RUNTIME, 0));
    TEST_REQUIRE(strstr(HARNESS_OUTPUT, "RGR needs a graphics device") != NULL,
		 "RGR(1) with no device should refuse, got \"%s\"", HARNESS_OUTPUT);
    harness_stop();
}

/** @brief GRAPHIC records the mode, clears on request and refuses a bad mode. */
static void test_graphic(void)
{
    TEST_REQUIRE_OK(run_program("10 GRAPHIC 1, 1\n"));
    TEST_REQUIRE_STR(MOCK.log, "clear #000000\n");
    TEST_REQUIRE_INT(HARNESS_RUNTIME.gfx.mode, 1);
    harness_stop();

    /* Without the clear argument nothing reaches the device. */
    TEST_REQUIRE_OK(run_program("10 GRAPHIC 1\n"));
    TEST_REQUIRE_STR(MOCK.log, "");
    harness_stop();

    /* GRAPHIC CLR drops the saved shapes and resets the whole state. */
    TEST_REQUIRE_OK(run_program("10 COLOR 1, 3\n20 GRAPHIC 5\n"));
    TEST_REQUIRE_STR(MOCK.log, "freeshapes\n");
    TEST_REQUIRE_INT(HARNESS_RUNTIME.gfx.source[1], 2);
    harness_stop();

    TEST_REQUIRE_OK(run_program("10 GRAPHIC 9\n"));
    TEST_REQUIRE(strstr(HARNESS_OUTPUT, "GRAPHIC mode 9") != NULL,
		 "an out-of-range mode should be refused, got \"%s\"", HARNESS_OUTPUT);
    harness_stop();
}

/** @brief SSHAPE stores a handle a later GSHAPE can use, and only that. */
static void test_shapes(void)
{
    TEST_REQUIRE_OK(run_program("10 SSHAPE A$, 0, 0, 8, 8\n20 GSHAPE A$, 32, 32\n"));
    TEST_REQUIRE_STR(MOCK.log, "save 0,0-8,8 -> 0\npaste 0 at 32.0,32.0\n");
    harness_stop();

    /*
     * The string is opaque but not magic: a string that did not come from SSHAPE
     * has to be refused, or GSHAPE parses whatever digits it finds and pastes
     * some unrelated slot.
     */
    TEST_REQUIRE_OK(run_program("10 A$ = \"5\"\n20 GSHAPE A$, 0, 0\n"));
    TEST_REQUIRE(strstr(HARNESS_OUTPUT, "did not come from SSHAPE") != NULL,
		 "a hand-written shape string should be refused, got \"%s\"", HARNESS_OUTPUT);
    harness_stop();

    /* A numeric variable is the wrong type for either verb. */
    TEST_REQUIRE_OK(run_program("10 SSHAPE A#, 0, 0, 8, 8\n"));
    TEST_REQUIRE(strstr(HARNESS_OUTPUT, "string variable") != NULL,
		 "SSHAPE into a number should be refused, got \"%s\"", HARNESS_OUTPUT);
    harness_stop();
}

/**
 * @brief Both verbs honour a subscript on a string array.
 *
 * They used to ignore it. `shape_variable()` took the identifier and looked the
 * variable up without evaluating the subscript, and both verbs then addressed
 * element zero with a literal -- so `SSHAPE SH$(2), ...` wrote the handle into
 * `SH$(0)` and `GSHAPE SH$(2)` stamped whatever was in `SH$(0)`.
 *
 * Ordinary assignment and `PRINT` honour the subscript, which is what made it
 * expensive: a program keeping several saved shapes in an array got every one of
 * them resolving to the same element, silently, and the only symptom was that
 * every stamp came out as the last shape captured. The Breakout in `examples/`
 * keeps its six brick stamps in six separate scalars because of this. TODO.md
 * section 9 item 6.
 */
static void test_shape_subscripts(void)
{
    TEST_REQUIRE_OK(run_program("10 DIM SH$(4)\n"
				"20 SSHAPE SH$(2), 0, 0, 8, 8\n"
				"30 PRINT \"[\" + SH$(0) + \"] [\" + SH$(2) + \"]\"\n"));
    /* The reduction from TODO.md, which used to print "[SHAPE:0] []". */
    TEST_REQUIRE_STR(HARNESS_OUTPUT, "[] [SHAPE:0]\n");
    harness_stop();

    /*
     * Two shapes in two elements, which is the case a program actually wants and
     * the one that came out wrong: the second capture used to overwrite the
     * first, so both elements named the same handle.
     */
    TEST_REQUIRE_OK(run_program("10 DIM SH$(4)\n"
				"20 SSHAPE SH$(1), 0, 0, 8, 8\n"
				"30 SSHAPE SH$(2), 0, 0, 4, 4\n"
				"40 PRINT \"[\" + SH$(1) + \"] [\" + SH$(2) + \"]\"\n"
				"50 GSHAPE SH$(2), 10, 10\n"
				"60 GSHAPE SH$(1), 20, 20\n"));
    TEST_REQUIRE_STR(HARNESS_OUTPUT, "[SHAPE:0] [SHAPE:1]\n");
    /* And each GSHAPE stamps the handle its own element names. */
    TEST_REQUIRE_STR(MOCK.log,
		     "save 0,0-8,8 -> 0\n"
		     "save 0,0-4,4 -> 1\n"
		     "paste 1 at 10.0,10.0\n"
		     "paste 0 at 20.0,20.0\n");
    harness_stop();
}

/**
 * @brief Every verb that needs a device says so by name when it has none.
 *
 * This is the standalone driver's situation, so it is the common path. COLOR,
 * LOCATE and SCALE are excluded on purpose: they only touch interpreter state
 * and must keep working before a host has lent the script a renderer.
 */
static void test_no_device(void)
{
    TEST_REQUIRE_OK(harness_start(NULL));
    TEST_REQUIRE_OK(akbasic_runtime_load(&HARNESS_RUNTIME,
					 "10 COLOR 1, 3\n"
					 "20 LOCATE 5, 5\n"
					 "30 SCALE 1\n"
					 "40 DRAW 1, 1, 1\n"));
    TEST_REQUIRE_OK(akbasic_runtime_start(&HARNESS_RUNTIME, AKBASIC_MODE_RUN));
    TEST_REQUIRE_OK(akbasic_runtime_run(&HARNESS_RUNTIME, 0));
    TEST_REQUIRE(strstr(HARNESS_OUTPUT, "DRAW needs a graphics device") != NULL,
		 "DRAW without a device should name itself, got \"%s\"", HARNESS_OUTPUT);
    TEST_REQUIRE(strstr(HARNESS_OUTPUT, "COLOR") == NULL,
		 "COLOR should not need a device, got \"%s\"", HARNESS_OUTPUT);
    TEST_REQUIRE_INT(HARNESS_RUNTIME.gfx.source[1], 3);
    TEST_REQUIRE_FEQ(HARNESS_RUNTIME.gfx.x, 5.0);
    TEST_REQUIRE(HARNESS_RUNTIME.gfx.scaling, "SCALE should not need a device");
    harness_stop();
}

int main(void)
{
    test_draw();
    test_color();
    test_box();
    test_circle();
    test_paint();
    test_scale();
    test_scale_without_a_size();
    test_rgr();
    test_graphic();
    test_shapes();
    test_shape_subscripts();
    test_no_device();
    return akbasic_test_failures;
}