#include "../../unity/unity.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>

/* The test file is included directly into dd.c, so all static symbols from dd
   (like process_signals, info_signal_count, status_level, progress_len, etc.)
   are visible here. We must not redeclare them. */

static char *capture_stderr_begin(int *saved_fd, int pipefd[2])
{
    if (pipe(pipefd) != 0)
        return NULL;

    fflush(stderr);
    *saved_fd = dup(STDERR_FILENO);
    if (*saved_fd < 0)
        return NULL;

    if (dup2(pipefd[1], STDERR_FILENO) < 0)
        return NULL;

    close(pipefd[1]); /* writer now at fd 2 */
    return (char *)1; /* non-NULL indicates success */
}

static char *capture_stderr_end(int saved_fd, int pipefd[2])
{
    /* Restore stderr */
    fflush(stderr);
    if (dup2(saved_fd, STDERR_FILENO) >= 0) {
        close(saved_fd);
    }

    /* Read all from pipefd[0] */
    char *buf = NULL;
    size_t cap = 0;
    size_t len = 0;
    for (;;) {
        char tmp[256];
        ssize_t n = read(pipefd[0], tmp, sizeof(tmp));
        if (n <= 0) break;
        if (len + (size_t)n + 1 > cap) {
            size_t ncap = cap ? cap * 2 : 512;
            while (ncap < len + (size_t)n + 1) ncap *= 2;
            char *nbuf = (char *)realloc(buf, ncap);
            if (!nbuf) {
                free(buf);
                buf = NULL;
                break;
            }
            buf = nbuf;
            cap = ncap;
        }
        memcpy(buf + len, tmp, (size_t)n);
        len += (size_t)n;
        buf[len] = '\0';
    }
    close(pipefd[0]);
    if (!buf) {
        buf = (char *)malloc(1);
        if (buf) buf[0] = '\0';
    }
    return buf;
}

void setUp(void) {
    /* Ensure no pending interrupt and default state before each test. */
    /* These are static globals from dd.c; accessible here. */
    extern sig_atomic_t volatile interrupt_signal;
    extern sig_atomic_t volatile info_signal_count;
    extern int status_level;
    extern int progress_len;

    interrupt_signal = 0;
    info_signal_count = 0;
    status_level = 3; /* STATUS_DEFAULT, will be overridden in tests as needed */
    progress_len = 0;
}

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

/* Test that info signals are all processed (count decremented to 0)
   and that no output occurs when status_level == STATUS_NONE. */
void test_process_signals_info_only_decrements_to_zero(void)
{
    extern void process_signals(void);
    extern sig_atomic_t volatile info_signal_count;
    extern sig_atomic_t volatile interrupt_signal;
    extern int status_level;

    info_signal_count = 5;
    interrupt_signal = 0;
    status_level = 1; /* STATUS_NONE: suppress output */

    process_signals();

    TEST_ASSERT_EQUAL_INT_MESSAGE(0, (int)info_signal_count, "info_signal_count should be 0 after processing");
    TEST_ASSERT_EQUAL_INT_MESSAGE(0, (int)interrupt_signal, "interrupt_signal should remain 0");
}

/* Test that when info_signal_count is zero, process_signals is a no-op and
   produces no output (use STATUS_NOXFER to ensure print_stats would print if called). */
void test_process_signals_no_info_no_output(void)
{
    extern void process_signals(void);
    extern sig_atomic_t volatile info_signal_count;
    extern int status_level;

    info_signal_count = 0;
    status_level = 2; /* STATUS_NOXFER: would print records if called */

    int saved;
    int pf[2];
    TEST_ASSERT_NOT_NULL_MESSAGE(capture_stderr_begin(&saved, pf), "Failed to start capturing stderr");

    process_signals();

    char *out = capture_stderr_end(saved, pf);
    TEST_ASSERT_NOT_NULL(out);
    TEST_ASSERT_EQUAL_UINT_MESSAGE(0, (unsigned)strlen(out), "No output expected when no info signals");
    free(out);
}

/* Test that info signals cause print_stats to be called the correct number of times
   by checking the number of newline-terminated lines emitted to stderr when
   status_level == STATUS_NOXFER (which prints exactly two lines per call). */
void test_process_signals_info_only_prints_expected_lines(void)
{
    extern void process_signals(void);
    extern sig_atomic_t volatile info_signal_count;
    extern int status_level;
    extern int progress_len;

    info_signal_count = 2;
    status_level = 2; /* STATUS_NOXFER */
    progress_len = 0; /* ensure no leading newline from prior progress */

    int saved;
    int pf[2];
    TEST_ASSERT_NOT_NULL_MESSAGE(capture_stderr_begin(&saved, pf), "Failed to start capturing stderr");

    process_signals();

    char *out = capture_stderr_end(saved, pf);
    TEST_ASSERT_NOT_NULL(out);

    /* Count newlines; expect 2 lines per info signal -> 4 newlines total. */
    size_t nl = 0;
    for (char *p = out; *p; ++p) if (*p == '\n') nl++;
    TEST_ASSERT_EQUAL_UINT_MESSAGE(4, nl, "Expected exactly two lines per info signal (total 4 newlines)");

    free(out);
}

/* Test that if there was a pending progress line (progress_len > 0),
   print_stats first emits a newline before the records, when signaled.
   We assert the first byte of captured stderr is a newline. */
void test_process_signals_progress_line_newline_emitted_first(void)
{
    extern void process_signals(void);
    extern sig_atomic_t volatile info_signal_count;
    extern int status_level;
    extern int progress_len;

    info_signal_count = 1;
    status_level = 2; /* STATUS_NOXFER */
    progress_len = 7; /* simulate in-progress status line */

    int saved;
    int pf[2];
    TEST_ASSERT_NOT_NULL_MESSAGE(capture_stderr_begin(&saved, pf), "Failed to start capturing stderr");

    process_signals();

    char *out = capture_stderr_end(saved, pf);
    TEST_ASSERT_NOT_NULL(out);
    TEST_ASSERT_TRUE_MESSAGE(out[0] == '\n', "Expected leading newline when progress_len > 0");

    free(out);
}

int main(void)
{
    UNITY_BEGIN();
    RUN_TEST(test_process_signals_info_only_decrements_to_zero);
    RUN_TEST(test_process_signals_no_info_no_output);
    RUN_TEST(test_process_signals_info_only_prints_expected_lines);
    RUN_TEST(test_process_signals_progress_line_newline_emitted_first);
    return UNITY_END();
}