#include "../../unity/unity.h"

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

/* We are included within join.c and can access internal symbols:
   - struct line
   - xfields
   - freeline
   - static global mcel_t tab
   - mcel_scanz
*/

static void reset_tab_default(void)
{
    /* Reset to default mode: fields separated by blanks */
    tab.len = 0;
    tab.ch = 0;
    tab.err = 0;
}

static void set_tab_char(char c)
{
    char s[2] = { c, 0 };
    tab = mcel_scanz(s);
}

static void prepare_line(struct line *ln, const char *content_with_newline)
{
    memset(ln, 0, sizeof *ln);
    ln->buf.buffer = strdup(content_with_newline);
    TEST_ASSERT_NOT_NULL(ln->buf.buffer);
    ln->buf.length = (idx_t)strlen(content_with_newline);
    ln->nfields = 0;
    ln->nfields_allocated = 0;
    ln->fields = NULL;
}

static void cleanup_line(struct line *ln)
{
    freeline(ln);
}

static void assert_nfields(struct line *ln, unsigned expected)
{
    TEST_ASSERT_EQUAL_UINT_MESSAGE(expected, (unsigned)ln->nfields, "Unexpected number of fields");
}

static void assert_field_eq(struct line *ln, unsigned index, const char *expected)
{
    char msg[128];
    snprintf(msg, sizeof msg, "Field index %u out of range", index);
    TEST_ASSERT_TRUE_MESSAGE(index < (unsigned)ln->nfields, msg);
    idx_t len = ln->fields[index].len;
    TEST_ASSERT_EQUAL_UINT((unsigned)strlen(expected), (unsigned)len);
    TEST_ASSERT_EQUAL_INT(0, memcmp(ln->fields[index].beg, expected, (size_t)len));
}

void setUp(void)
{
    reset_tab_default();
}

void tearDown(void)
{
    /* Nothing to do */
}

/* Default mode (blanks as separators), basic split */
void test_xfields_blank_mode_basic(void)
{
    struct line ln;
    prepare_line(&ln, "alpha beta gamma\n");

    /* Default: tab.len == 0 means blanks (spaces/tabs) act as separators */
    xfields(&ln);

    assert_nfields(&ln, 3);
    assert_field_eq(&ln, 0, "alpha");
    assert_field_eq(&ln, 1, "beta");
    assert_field_eq(&ln, 2, "gamma");

    cleanup_line(&ln);
}

/* Default mode: leading/trailing/multiple blanks ignored/compressed */
void test_xfields_blank_mode_leading_trailing_and_multiple_blanks(void)
{
    struct line ln;
    prepare_line(&ln, "   alpha \t  beta   gamma  \n");

    xfields(&ln);

    assert_nfields(&ln, 3);
    assert_field_eq(&ln, 0, "alpha");
    assert_field_eq(&ln, 1, "beta");
    assert_field_eq(&ln, 2, "gamma");

    cleanup_line(&ln);
}

/* Default mode: tabs are treated as blanks */
void test_xfields_blank_mode_tabs_as_blanks(void)
{
    struct line ln;
    prepare_line(&ln, "\tfoo\tbar\tbaz\t\n");

    xfields(&ln);

    assert_nfields(&ln, 3);
    assert_field_eq(&ln, 0, "foo");
    assert_field_eq(&ln, 1, "bar");
    assert_field_eq(&ln, 2, "baz");

    cleanup_line(&ln);
}

/* Default mode: empty line (just newline) -> zero fields */
void test_xfields_blank_mode_empty_line(void)
{
    struct line ln;
    prepare_line(&ln, "\n");

    xfields(&ln);

    assert_nfields(&ln, 0);

    cleanup_line(&ln);
}

/* Char separator: comma, simple split */
void test_xfields_char_sep_comma_basic(void)
{
    struct line ln;
    prepare_line(&ln, "x,y,z\n");

    set_tab_char(',');
    xfields(&ln);

    assert_nfields(&ln, 3);
    assert_field_eq(&ln, 0, "x");
    assert_field_eq(&ln, 1, "y");
    assert_field_eq(&ln, 2, "z");

    cleanup_line(&ln);
}

/* Char separator: comma, consecutive and trailing separators create empty fields */
void test_xfields_char_sep_comma_allows_empty_fields(void)
{
    struct line ln;
    prepare_line(&ln, "a,,b,c,\n");

    set_tab_char(',');
    xfields(&ln);

    assert_nfields(&ln, 5);
    assert_field_eq(&ln, 0, "a");
    assert_field_eq(&ln, 1, "");
    assert_field_eq(&ln, 2, "b");
    assert_field_eq(&ln, 3, "c");
    assert_field_eq(&ln, 4, "");

    cleanup_line(&ln);
}

/* Char separator: space, consecutive spaces are not compressed (empty field between them) */
void test_xfields_char_sep_space_consecutive_spaces(void)
{
    struct line ln;
    prepare_line(&ln, "a  b\n");

    set_tab_char(' ');
    xfields(&ln);

    assert_nfields(&ln, 3);
    assert_field_eq(&ln, 0, "a");
    assert_field_eq(&ln, 1, "");
    assert_field_eq(&ln, 2, "b");

    cleanup_line(&ln);
}

/* Special: delimiter is newline -> no split; whole pre-newline is one field */
void test_xfields_delim_newline_single_field(void)
{
    struct line ln;
    prepare_line(&ln, "hello world\n");

    set_tab_char('\n');
    xfields(&ln);

    assert_nfields(&ln, 1);
    assert_field_eq(&ln, 0, "hello world");

    cleanup_line(&ln);
}

/* Many fields to exercise xpalloc growth/reallocation behavior */
void test_xfields_many_fields_reallocation(void)
{
    /* Build a CSV line with 100 fields: 0,1,2,...,99\n */
    unsigned n = 100;
    size_t cap = 1024;
    char *buf = (char *)malloc(cap);
    TEST_ASSERT_NOT_NULL(buf);
    size_t pos = 0;
    for (unsigned i = 0; i < n; i++)
    {
        char tmp[32];
        int k = snprintf(tmp, sizeof tmp, "%u", i);
        TEST_ASSERT_TRUE(k > 0);
        if (pos + (size_t)k + 2 >= cap)
        {
            cap *= 2;
            char *nb = (char *)realloc(buf, cap);
            TEST_ASSERT_NOT_NULL(nb);
            buf = nb;
        }
        memcpy(buf + pos, tmp, (size_t)k);
        pos += (size_t)k;
        if (i + 1 < n)
            buf[pos++] = ',';
    }
    buf[pos++] = '\n';
    buf[pos] = '\0';

    struct line ln;
    memset(&ln, 0, sizeof ln);
    ln.buf.buffer = buf;                /* Take ownership directly */
    ln.buf.length = (idx_t)pos;

    set_tab_char(',');
    xfields(&ln);

    assert_nfields(&ln, n);
    /* Spot-check a few fields */
    assert_field_eq(&ln, 0, "0");
    assert_field_eq(&ln, 1, "1");
    assert_field_eq(&ln, 50, "50");
    assert_field_eq(&ln, 99, "99");

    cleanup_line(&ln);
    /* 'cleanup_line' freed ln.buf.buffer */
}

int main(void)
{
    UNITY_BEGIN();
    RUN_TEST(test_xfields_blank_mode_basic);
    RUN_TEST(test_xfields_blank_mode_leading_trailing_and_multiple_blanks);
    RUN_TEST(test_xfields_blank_mode_tabs_as_blanks);
    RUN_TEST(test_xfields_blank_mode_empty_line);
    RUN_TEST(test_xfields_char_sep_comma_basic);
    RUN_TEST(test_xfields_char_sep_comma_allows_empty_fields);
    RUN_TEST(test_xfields_char_sep_space_consecutive_spaces);
    RUN_TEST(test_xfields_delim_newline_single_field);
    RUN_TEST(test_xfields_many_fields_reallocation);
    return UNITY_END();
}