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

/* Forward declarations of tested/internal functions and globals are not needed
   since this file is textually included into the same translation unit. */

/* Helper to create a temporary file with given contents. */
static FILE* make_file(const char* s)
{
    FILE* f = tmpfile();
    TEST_ASSERT_NOT_NULL_MESSAGE(f, "tmpfile failed");
    size_t len = strlen(s);
    if (len > 0) {
        size_t n = fwrite(s, 1, len, f);
        TEST_ASSERT_TRUE_MESSAGE(n == len, "failed to write all data to tmpfile");
    }
    rewind(f);
    return f;
}

void setUp(void) {
    /* Nothing to set up by default */
}

void tearDown(void) {
    /* Nothing to tear down by default */
}

/* Tests start here */

void test_get_prefix_empty_prefix_with_leading_spaces(void)
{
    char pfx[] = "  "; /* trimmed -> prefix_length=0, prefix_lead_space=2 */
    set_prefix(pfx);
    tabs = false;

    FILE* f = make_file("   abc\n");
    int c = get_prefix(f);

    TEST_ASSERT_EQUAL_INT('a', c);
    TEST_ASSERT_EQUAL_INT(3, in_column);
    TEST_ASSERT_EQUAL_INT(2, next_prefix_indent);
    TEST_ASSERT_FALSE(tabs);

    int next = getc(f);
    TEST_ASSERT_EQUAL_INT('b', next);
    fclose(f);
}

void test_get_prefix_nonempty_prefix_exact_match_with_trailing_spaces(void)
{
    char pfx[] = "  abc  "; /* trimmed -> "abc", lead=2 */
    set_prefix(pfx);
    tabs = false;

    FILE* f = make_file("    abc   xyz\n");
    int c = get_prefix(f);

    TEST_ASSERT_EQUAL_INT('x', c);
    TEST_ASSERT_EQUAL_INT(10, in_column);      /* 4 spaces + 3 + 3 trailing spaces */
    TEST_ASSERT_EQUAL_INT(4, next_prefix_indent);
    TEST_ASSERT_FALSE(tabs);

    int next = getc(f);
    TEST_ASSERT_EQUAL_INT('y', next);
    fclose(f);
}

void test_get_prefix_mismatch_first_char(void)
{
    char pfx[] = "abc";
    set_prefix(pfx);
    tabs = false;

    FILE* f = make_file("   Xdef\n");
    int c = get_prefix(f);

    TEST_ASSERT_EQUAL_INT('X', c);
    TEST_ASSERT_EQUAL_INT(3, in_column);
    TEST_ASSERT_EQUAL_INT(3, next_prefix_indent);
    TEST_ASSERT_FALSE(tabs);

    int next = getc(f);
    TEST_ASSERT_EQUAL_INT('d', next);
    fclose(f);
}

void test_get_prefix_partial_match_then_mismatch_mid_prefix(void)
{
    char pfx[] = "abz";
    set_prefix(pfx);
    tabs = false;

    FILE* f = make_file(" abXq\n");
    int c = get_prefix(f);

    TEST_ASSERT_EQUAL_INT('X', c);
    TEST_ASSERT_EQUAL_INT(3, in_column);   /* 1 space + 'a' + 'b' */
    TEST_ASSERT_EQUAL_INT(1, next_prefix_indent);
    TEST_ASSERT_FALSE(tabs);

    int next = getc(f);
    TEST_ASSERT_EQUAL_INT('q', next);
    fclose(f);
}

void test_get_prefix_empty_prefix_uses_min_of_lead_and_indent(void)
{
    char pfx[] = "   "; /* lead=3, prefix_length=0 */
    set_prefix(pfx);
    tabs = false;

    FILE* f = make_file("  a");
    int c = get_prefix(f);

    TEST_ASSERT_EQUAL_INT('a', c);
    TEST_ASSERT_EQUAL_INT(2, in_column);
    TEST_ASSERT_EQUAL_INT(2, next_prefix_indent); /* min(3,2)=2 */
    TEST_ASSERT_FALSE(tabs);

    int next = getc(f);
    /* After returning 'a', stream advanced; next should be EOF here */
    TEST_ASSERT_EQUAL_INT(EOF, next);
    fclose(f);
}

void test_get_prefix_tabs_with_empty_prefix_sets_tabs_and_indent(void)
{
    char pfx[] = ""; /* lead=0, prefix_length=0 */
    set_prefix(pfx);
    tabs = false;

    FILE* f = make_file("\t\tA");
    int c = get_prefix(f);

    TEST_ASSERT_EQUAL_INT('A', c);
    TEST_ASSERT_TRUE(tabs);
    TEST_ASSERT_EQUAL_INT(16, in_column);       /* two tabs -> 16 columns */
    TEST_ASSERT_EQUAL_INT(0, next_prefix_indent);

    int next = getc(f);
    TEST_ASSERT_EQUAL_INT(EOF, next);
    fclose(f);
}

void test_get_prefix_tab_before_nonempty_prefix(void)
{
    char pfx[] = "XYZ";
    set_prefix(pfx);
    tabs = false;

    FILE* f = make_file("\tXYZ  QR");
    int c = get_prefix(f);

    TEST_ASSERT_TRUE(tabs);
    TEST_ASSERT_EQUAL_INT('Q', c);
    TEST_ASSERT_EQUAL_INT(8, next_prefix_indent);   /* tab to column 8 */
    TEST_ASSERT_EQUAL_INT(13, in_column);           /* 8 + 3 + 2 spaces */

    int next = getc(f);
    TEST_ASSERT_EQUAL_INT('R', next);
    fclose(f);
}

void test_get_prefix_eof_immediately(void)
{
    char pfx[] = ""; /* empty; lead=0 */
    set_prefix(pfx);
    tabs = false;

    FILE* f = make_file("");
    int c = get_prefix(f);

    TEST_ASSERT_EQUAL_INT(EOF, c);
    TEST_ASSERT_EQUAL_INT(0, in_column);
    TEST_ASSERT_EQUAL_INT(0, next_prefix_indent);
    TEST_ASSERT_FALSE(tabs);
    fclose(f);
}

void test_get_prefix_prefix_match_followed_by_tabs(void)
{
    char pfx[] = "P";
    set_prefix(pfx);
    tabs = false;

    FILE* f = make_file(" P\t\tA");
    int c = get_prefix(f);

    TEST_ASSERT_EQUAL_INT('A', c);
    TEST_ASSERT_TRUE(tabs);
    TEST_ASSERT_EQUAL_INT(1, next_prefix_indent); /* one leading space */
    TEST_ASSERT_EQUAL_INT(16, in_column);         /* after 'P' (col 2), two tabs -> col 16 */

    int next = getc(f);
    TEST_ASSERT_EQUAL_INT(EOF, next);
    fclose(f);
}

void test_get_prefix_newline_immediately_nonempty_prefix(void)
{
    char pfx[] = "x";
    set_prefix(pfx);
    tabs = false;

    FILE* f = make_file("\nA");
    int c = get_prefix(f);

    TEST_ASSERT_EQUAL_INT('\n', c);
    TEST_ASSERT_EQUAL_INT(0, in_column);
    TEST_ASSERT_EQUAL_INT(0, next_prefix_indent);
    TEST_ASSERT_FALSE(tabs);

    int next = getc(f);
    TEST_ASSERT_EQUAL_INT('A', next);
    fclose(f);
}

int main(void)
{
    UNITY_BEGIN();

    RUN_TEST(test_get_prefix_empty_prefix_with_leading_spaces);
    RUN_TEST(test_get_prefix_nonempty_prefix_exact_match_with_trailing_spaces);
    RUN_TEST(test_get_prefix_mismatch_first_char);
    RUN_TEST(test_get_prefix_partial_match_then_mismatch_mid_prefix);
    RUN_TEST(test_get_prefix_empty_prefix_uses_min_of_lead_and_indent);
    RUN_TEST(test_get_prefix_tabs_with_empty_prefix_sets_tabs_and_indent);
    RUN_TEST(test_get_prefix_tab_before_nonempty_prefix);
    RUN_TEST(test_get_prefix_eof_immediately);
    RUN_TEST(test_get_prefix_prefix_match_followed_by_tabs);
    RUN_TEST(test_get_prefix_newline_immediately_nonempty_prefix);

    return UNITY_END();
}