#include "../../unity/unity.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

/* The test file is included after the program, so we can access the
   program's internal (file-scope static) data and helpers directly. */

/* Forward declarations for clarity are unnecessary since we're included
   after definitions, but we annotate intent here: we use
   - static bool get_line (FILE *fp, struct line **linep, int which)
   - static void freeline (struct line *line)
   - static void free_spareline (void)
   and we access globals like prevline, spareline, line_no, eolchar,
   check_input_order, join_field_1/2, issued_disorder_warning, etc. */

/* Helper: create a temporary FILE* preloaded with the provided data. */
static FILE* make_temp_file_with(const char* data)
{
    FILE* fp = tmpfile();
    TEST_ASSERT_NOT_NULL_MESSAGE(fp, "tmpfile failed");
    size_t len = strlen(data);
    if (len) {
        size_t nw = fwrite(data, 1, len, fp);
        TEST_ASSERT_EQUAL_size_t(len, nw);
    }
    rewind(fp);
    return fp;
}

/* Helper: free and null any prevline/spareline state to keep tests isolated. */
static void cleanup_lines_state(void)
{
    for (int i = 0; i < 2; ++i) {
        if (prevline[i]) {
            freeline(prevline[i]);
            free(prevline[i]);
            prevline[i] = NULL;
        }
        if (spareline[i]) {
            freeline(spareline[i]);
            free(spareline[i]);
            spareline[i] = NULL;
        }
    }
}

void setUp(void)
{
    /* Reset line-related state */
    cleanup_lines_state();
    line_no[0] = 0;
    line_no[1] = 0;

    /* Reset parsing and behavior globals to simple defaults */
    eolchar = '\n';

    /* Ensure we never call check_order during these tests */
    check_input_order = CHECK_ORDER_DISABLED;

    /* Reset other global flags that could affect behavior */
    seen_unpairable = false;
    issued_disorder_warning[0] = false;
    issued_disorder_warning[1] = false;
    join_field_1 = -1;
    join_field_2 = -1;
}

void tearDown(void)
{
    cleanup_lines_state();
}

static void assert_field_eq(const struct field* f, const char* expect)
{
    size_t elen = strlen(expect);
    TEST_ASSERT_EQUAL_size_t(elen, (size_t)f->len);
    TEST_ASSERT_EQUAL_INT(0, memcmp(f->beg, expect, elen));
}

void test_get_line_basic_parsing_file1(void)
{
    FILE* fp = make_temp_file_with("a b c\n");

    struct line* line = NULL;
    bool ok = get_line(fp, &line, 1);
    TEST_ASSERT_TRUE(ok);
    TEST_ASSERT_NOT_NULL(line);
    TEST_ASSERT_NOT_NULL(line->buf.buffer);
    TEST_ASSERT_EQUAL_UINT64(1, line_no[0]);
    TEST_ASSERT_EQUAL_UINT64(0, line_no[1]);
    TEST_ASSERT_EQUAL_PTR(line, prevline[0]);

    /* Basic field parsing with default blank separators */
    TEST_ASSERT_EQUAL_INT(3, (int)line->nfields);
    assert_field_eq(&line->fields[0], "a");
    assert_field_eq(&line->fields[1], "b");
    assert_field_eq(&line->fields[2], "c");

    /* Buffer should end with eolchar */
    TEST_ASSERT_TRUE(line->buf.length > 0);
    TEST_ASSERT_EQUAL_CHAR('\n', line->buf.buffer[line->buf.length - 1]);

    fclose(fp);
}

void test_get_line_spareline_swap_prevents_overwrite(void)
{
    /* Two lines; ensure spareline swap triggers on second read when *linep
       equals prevline */
    FILE* fp = make_temp_file_with("x y\nxy z\n");

    struct line* line = NULL;
    bool ok1 = get_line(fp, &line, 1);
    TEST_ASSERT_TRUE(ok1);
    struct line* first_line = line; /* This equals prevline[0] now */

    /* Read next line using the same line pointer; this triggers the swap to spareline */
    bool ok2 = get_line(fp, &line, 1);
    TEST_ASSERT_TRUE(ok2);

    /* After swap, spareline[0] should hold the previous line, and prevline[0] should be the new line */
    TEST_ASSERT_EQUAL_PTR(first_line, spareline[0]);
    TEST_ASSERT_EQUAL_PTR(line, prevline[0]);
    TEST_ASSERT_EQUAL_UINT64(2, line_no[0]);

    /* Verify content of the newly read line */
    TEST_ASSERT_NOT_NULL(line);
    TEST_ASSERT_EQUAL_INT(2, (int)line->nfields);
    assert_field_eq(&line->fields[0], "xy");
    assert_field_eq(&line->fields[1], "z");

    /* Ensure the first line's data remains intact in spareline */
    TEST_ASSERT_NOT_NULL(spareline[0]);
    TEST_ASSERT_TRUE(spareline[0]->nfields >= 2);
    assert_field_eq(&spareline[0]->fields[0], "x");
    assert_field_eq(&spareline[0]->fields[1], "y");

    fclose(fp);
}

void test_get_line_empty_line_zero_fields(void)
{
    FILE* fp = make_temp_file_with("\n");

    struct line* line = NULL;
    bool ok = get_line(fp, &line, 1);
    TEST_ASSERT_TRUE(ok);
    TEST_ASSERT_NOT_NULL(line);
    TEST_ASSERT_EQUAL_INT(0, (int)line->nfields);

    fclose(fp);
}

void test_get_line_eof_returns_false_and_frees_buffers(void)
{
    FILE* fp = make_temp_file_with("a\n");

    struct line* line = NULL;
    bool ok1 = get_line(fp, &line, 1);
    TEST_ASSERT_TRUE(ok1);
    TEST_ASSERT_NOT_NULL(line);

    struct line* prev = line; /* equals prevline[0] */

    /* Next call should hit EOF. Since we pass the same pointer, swap logic runs. */
    bool ok2 = get_line(fp, &line, 1);
    TEST_ASSERT_FALSE(ok2);

    /* After false return, the (new) line struct remains allocated but buffers are freed. */
    TEST_ASSERT_NOT_NULL(line);
    TEST_ASSERT_NULL(line->buf.buffer);
    TEST_ASSERT_NULL(line->fields);

    /* prevline[0] remains the previous successfully-read line; swap set spareline[0]=prev too */
    TEST_ASSERT_EQUAL_PTR(prev, prevline[0]);
    TEST_ASSERT_EQUAL_PTR(prev, spareline[0]);

    fclose(fp);
}

void test_get_line_parsing_with_leading_blanks(void)
{
    FILE* fp = make_temp_file_with("   hello   world  \n");

    struct line* line = NULL;
    bool ok = get_line(fp, &line, 1);
    TEST_ASSERT_TRUE(ok);
    TEST_ASSERT_NOT_NULL(line);

    TEST_ASSERT_EQUAL_INT(2, (int)line->nfields);
    assert_field_eq(&line->fields[0], "hello");
    assert_field_eq(&line->fields[1], "world");

    fclose(fp);
}

void test_get_line_file2_independent_state(void)
{
    FILE* fp1 = make_temp_file_with("a1 b1\n");
    FILE* fp2 = make_temp_file_with("a2 b2 c2\n");

    struct line* l1 = NULL;
    struct line* l2 = NULL;

    bool ok1 = get_line(fp1, &l1, 1);
    bool ok2 = get_line(fp2, &l2, 2);

    TEST_ASSERT_TRUE(ok1);
    TEST_ASSERT_TRUE(ok2);

    TEST_ASSERT_EQUAL_UINT64(1, line_no[0]);
    TEST_ASSERT_EQUAL_UINT64(1, line_no[1]);

    TEST_ASSERT_EQUAL_PTR(l1, prevline[0]);
    TEST_ASSERT_EQUAL_PTR(l2, prevline[1]);

    TEST_ASSERT_EQUAL_INT(2, (int)l1->nfields);
    assert_field_eq(&l1->fields[0], "a1");
    assert_field_eq(&l1->fields[1], "b1");

    TEST_ASSERT_EQUAL_INT(3, (int)l2->nfields);
    assert_field_eq(&l2->fields[0], "a2");
    assert_field_eq(&l2->fields[1], "b2");
    assert_field_eq(&l2->fields[2], "c2");

    fclose(fp1);
    fclose(fp2);
}

int main(void)
{
    UNITY_BEGIN();
    RUN_TEST(test_get_line_basic_parsing_file1);
    RUN_TEST(test_get_line_spareline_swap_prevents_overwrite);
    RUN_TEST(test_get_line_empty_line_zero_fields);
    RUN_TEST(test_get_line_eof_returns_false_and_frees_buffers);
    RUN_TEST(test_get_line_parsing_with_leading_blanks);
    RUN_TEST(test_get_line_file2_independent_state);
    return UNITY_END();
}