/* LINK: ../../src/error.c ../../src/span.c */
/* tests/unit/test_error.c
 *
 * Unit tests for the error + source-span diagnostic infrastructure.
 *
 * The magic LINK comment on line 1 is REQUIRED by tests/run.sh: it lists
 * the extra .c sources to compile into this test binary (paths relative
 * to tests/unit/, space-separated). munit.c and the include dirs are
 * added automatically by the harness.
 */
#include "munit.h"

#include "error.h"
#include "span.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/* Render into a tmpfile and slurp it back into a NUL-terminated string.
 * Returns NULL on any I/O failure. Caller frees with free(). */
static char *
capture(FILE *f)
{
    long n;
    char *buf;

    if (fseek(f, 0, SEEK_END) != 0) {
        return NULL;
    }
    n = ftell(f);
    if (n < 0 || fseek(f, 0, SEEK_SET) != 0) {
        return NULL;
    }
    buf = munit_malloc((size_t)n + 1);
    if (fread(buf, 1, (size_t)n, f) != (size_t)n) {
        free(buf);
        return NULL;
    }
    buf[n] = '\0';
    return buf;
}

/* (a) the canonical span renders byte-for-byte per the plan's contract. */
static MunitResult
test_span_exact_rendering(const MunitParameter params[], void *data)
{
    (void)params;
    (void)data;
    const struct st_span span = { "file.kdl", 3, 5 };
    FILE *f = tmpfile();
    char *got;

    munit_assert_not_null(f);
    st_span_print(f, &span, "<msg>");
    got = capture(f);
    fclose(f);
    munit_assert_not_null(got);
    munit_assert_string_equal(got, "file.kdl:3:5: <msg>\n    ...^\n");
    free(got);
    return MUNIT_OK;
}

/* (b) a span at line 0 / col 0 renders without underflow: no crash,
 * sane byte-exact output. */
static MunitResult
test_span_zero_coords_no_underflow(const MunitParameter params[], void *data)
{
    (void)params;
    (void)data;
    const struct st_span span = { "zero.kdl", 0, 0 };
    FILE *f = tmpfile();
    char *got;

    munit_assert_not_null(f);
    st_span_print(f, &span, "<msg>");
    got = capture(f);
    fclose(f);
    munit_assert_not_null(got);
    munit_assert_string_equal(got, "zero.kdl:0:0: <msg>\n    ...^\n");
    free(got);
    return MUNIT_OK;
}

/* (c) error categories round-trip through their constructors. */
static MunitResult
test_error_category_roundtrip(const MunitParameter params[], void *data)
{
    (void)params;
    (void)data;
    struct st_error *e = st_error_kdl_parse("<msg>");

    munit_assert_not_null(e);
    munit_assert_int(st_error_category_of(e), ==, ST_ERR_KDL_PARSE);
    munit_assert_string_equal(st_error_message(e), "<msg>");
    st_error_free(e);
    return MUNIT_OK;
}

/* every category constructor tags its own category. */
static MunitResult
test_error_constructors(const MunitParameter params[], void *data)
{
    (void)params;
    (void)data;
    struct st_error *e;

    e = st_error_kdl_schema("m");
    munit_assert_int(st_error_category_of(e), ==, ST_ERR_KDL_SCHEMA);
    st_error_free(e);

    e = st_error_io("m");
    munit_assert_int(st_error_category_of(e), ==, ST_ERR_IO);
    st_error_free(e);

    e = st_error_usage("m");
    munit_assert_int(st_error_category_of(e), ==, ST_ERR_USAGE);
    st_error_free(e);

    e = st_error_internal("m");
    munit_assert_int(st_error_category_of(e), ==, ST_ERR_INTERNAL);
    st_error_free(e);

    st_error_free(NULL); /* must be a safe no-op */
    return MUNIT_OK;
}

/* category names exist, are non-empty, and are pairwise distinct. */
static MunitResult
test_error_category_names(const MunitParameter params[], void *data)
{
    (void)params;
    (void)data;
    int c;
    const char *prev = NULL;

    for (c = ST_ERR_KDL_PARSE; c <= ST_ERR_INTERNAL; c++) {
        const char *n =
            st_error_category_name((enum st_error_category)c);
        munit_assert_not_null(n);
        munit_assert_int(strlen(n), >, 0);
        if (prev != NULL) {
            munit_assert_string_not_equal(n, prev);
        }
        prev = n;
    }
    return MUNIT_OK;
}

/* st_error_print with a span renders span shape + category-prefixed msg. */
static MunitResult
test_error_print_with_span(const MunitParameter params[], void *data)
{
    (void)params;
    (void)data;
    const struct st_span span = { "file.kdl", 3, 5 };
    struct st_error *e = st_error_at(st_error_kdl_parse("<msg>"), &span);
    FILE *f = tmpfile();
    char *got;

    munit_assert_not_null(e);
    munit_assert_not_null(f);
    st_error_print(f, e);
    got = capture(f);
    fclose(f);
    munit_assert_not_null(got);
    munit_assert_string_equal(
        got, "file.kdl:3:5: [kdl-parse] <msg>\n    ...^\n");
    free(got);
    st_error_free(e);
    return MUNIT_OK;
}

/* st_error_print without a span renders category-prefixed message only. */
static MunitResult
test_error_print_without_span(const MunitParameter params[], void *data)
{
    (void)params;
    (void)data;
    struct st_error *e = st_error_io("disk on fire");
    FILE *f = tmpfile();
    char *got;

    munit_assert_not_null(e);
    munit_assert_not_null(f);
    st_error_print(f, e);
    got = capture(f);
    fclose(f);
    munit_assert_not_null(got);
    munit_assert_string_equal(got, "[io] disk on fire\n");
    free(got);
    st_error_free(e);
    return MUNIT_OK;
}

static MunitTest tests[] = {
    { "/span/exact-rendering", test_span_exact_rendering, NULL, NULL,
      MUNIT_TEST_OPTION_NONE, NULL },
    { "/span/zero-coords-no-underflow", test_span_zero_coords_no_underflow,
      NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL },
    { "/error/category-roundtrip", test_error_category_roundtrip, NULL, NULL,
      MUNIT_TEST_OPTION_NONE, NULL },
    { "/error/constructors", test_error_constructors, NULL, NULL,
      MUNIT_TEST_OPTION_NONE, NULL },
    { "/error/category-names", test_error_category_names, NULL, NULL,
      MUNIT_TEST_OPTION_NONE, NULL },
    { "/error/print-with-span", test_error_print_with_span, NULL, NULL,
      MUNIT_TEST_OPTION_NONE, NULL },
    { "/error/print-without-span", test_error_print_without_span, NULL, NULL,
      MUNIT_TEST_OPTION_NONE, NULL },
    { NULL, NULL, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL },
};

static const MunitSuite suite = {
    "/error", tests, NULL, 1, MUNIT_SUITE_OPTION_NONE,
};

int
main(int argc, char *argv[MUNIT_ARRAY_PARAM(argc + 1)])
{
    return munit_suite_main(&suite, NULL, argc, argv);
}