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

/* The test file is included into the same translation unit as nl.c,
   so we can access file-scope static variables and functions directly. */

/* Forward declaration of target (has internal linkage, but visible here
   because we are included in the same translation unit). */
static bool nl_file (char const *file);

/* Globals from program, accessible here due to inclusion into same TU. */
extern char const *FORMAT_RIGHT_NOLZ; /* format const from program */
static void reset_lineno(void);       /* static in program, visible here by inclusion */

/* Helper: make a print_no_line_fmt based on width and separator. */
static char* make_print_no_line_fmt_buf(int width, const char* sep)
{
    size_t seplen = strlen(sep);
    char* s = (char*)malloc((size_t)width + seplen + 1);
    if (!s) return NULL;
    memset(s, ' ', (size_t)width);
    memcpy(s + width, sep, seplen);
    s[width + seplen] = '\0';
    return s;
}

/* Helper: write content to an already-open fd, then rewind position. */
static int write_all(int fd, const char* data, size_t len)
{
    size_t off = 0;
    while (off < len) {
        ssize_t w = write(fd, data + off, len - off);
        if (w < 0) return -1;
        off += (size_t)w;
    }
    return 0;
}

/* Helper: create a temp file with given content, return its path (malloc'd).
   Caller must free the returned path. */
static char* create_temp_file_with(const char* content)
{
    char tmpl[] = "/tmp/nl_test_XXXXXX";
    int fd = mkstemp(tmpl);
    if (fd < 0) return NULL;
    if (content && write_all(fd, content, strlen(content)) < 0) {
        close(fd);
        unlink(tmpl);
        return NULL;
    }
    /* Rewind the file for reading by nl_file. */
    lseek(fd, 0, SEEK_SET);
    close(fd);
    char* path = strdup(tmpl);
    return path;
}

/* Helper: read entire file into malloc'd buffer; returns NUL-terminated string. */
static char* read_entire_file(const char* path)
{
    FILE* f = fopen(path, "rb");
    if (!f) return NULL;
    if (fseek(f, 0, SEEK_END) != 0) { fclose(f); return NULL; }
    long sz = ftell(f);
    if (sz < 0) { fclose(f); return NULL; }
    if (fseek(f, 0, SEEK_SET) != 0) { fclose(f); return NULL; }
    char* buf = (char*)malloc((size_t)sz + 1);
    if (!buf) { fclose(f); return NULL; }
    size_t n = fread(buf, 1, (size_t)sz, f);
    buf[n] = '\0';
    fclose(f);
    return buf;
}

/* Helper: redirect stdout to a temp file, returning saved stdout fd and path to out file. */
static int redirect_stdout_to_temp(char** out_path)
{
    fflush(stdout);
    char tmpl[] = "/tmp/nl_out_XXXXXX";
    int outfd = mkstemp(tmpl);
    if (outfd < 0) return -1;
    int saved = dup(STDOUT_FILENO);
    if (saved < 0) { close(outfd); unlink(tmpl); return -1; }
    if (dup2(outfd, STDOUT_FILENO) < 0) {
        close(outfd);
        close(saved);
        unlink(tmpl);
        return -1;
    }
    close(outfd);
    *out_path = strdup(tmpl);
    return saved;
}

/* Helper: redirect stderr to a temp file, returning saved stderr fd and path. */
static int redirect_stderr_to_temp(char** err_path)
{
    fflush(stderr);
    char tmpl[] = "/tmp/nl_err_XXXXXX";
    int errfd = mkstemp(tmpl);
    if (errfd < 0) return -1;
    int saved = dup(STDERR_FILENO);
    if (saved < 0) { close(errfd); unlink(tmpl); return -1; }
    if (dup2(errfd, STDERR_FILENO) < 0) {
        close(errfd);
        close(saved);
        unlink(tmpl);
        return -1;
    }
    close(errfd);
    *err_path = strdup(tmpl);
    return saved;
}

/* Helper: restore stdout from saved fd. */
static void restore_stdout(int saved_fd)
{
    fflush(stdout);
    dup2(saved_fd, STDOUT_FILENO);
    close(saved_fd);
}

/* Helper: restore stderr from saved fd. */
static void restore_stderr(int saved_fd)
{
    fflush(stderr);
    dup2(saved_fd, STDERR_FILENO);
    close(saved_fd);
}

/* Helper: redirect stdin from a file, returning saved stdin fd. */
static int redirect_stdin_from_file(const char* path)
{
    int fd = open(path, O_RDONLY);
    if (fd < 0) return -1;
    int saved = dup(STDIN_FILENO);
    if (saved < 0) { close(fd); return -1; }
    if (dup2(fd, STDIN_FILENO) < 0) {
        close(fd);
        close(saved);
        return -1;
    }
    close(fd);
    return saved;
}

extern char const *separator_str;
extern int lineno_width;
extern char const *lineno_format;
extern char *print_no_line_fmt;
extern intmax_t starting_line_number;
extern intmax_t page_incr;
extern bool reset_numbers;
extern char const *body_type;
extern char const *header_type;
extern char const *footer_type;
extern char const *current_type;
extern bool have_read_stdin;

/* Keep track to free the allocated format string per test. */
static char* allocated_print_no_line_fmt = NULL;

/* Initialize core globals before each test. */
void setUp(void) {
    /* Defaults tailored for tests */
    separator_str = "\t";
    lineno_width = 2;
    lineno_format = FORMAT_RIGHT_NOLZ;
    starting_line_number = 1;
    page_incr = 1;
    reset_numbers = true;

    /* Ensure default numbering style is body "t". */
    body_type = "t";
    header_type = "n";
    footer_type = "n";
    current_type = body_type;

    /* Build the "no number" prefix: spaces + separator. */
    if (allocated_print_no_line_fmt) {
        free(allocated_print_no_line_fmt);
        allocated_print_no_line_fmt = NULL;
    }
    allocated_print_no_line_fmt = make_print_no_line_fmt_buf(lineno_width, separator_str);
    print_no_line_fmt = allocated_print_no_line_fmt;

    /* Set initial line number. */
    reset_lineno();

    /* Clear have_read_stdin for tests that inspect it. */
    have_read_stdin = false;
}

void tearDown(void) {
    if (allocated_print_no_line_fmt) {
        free(allocated_print_no_line_fmt);
        allocated_print_no_line_fmt = NULL;
        print_no_line_fmt = NULL;
    }
}

/* Test 1: Simple numbering of a regular file with two non-empty lines. */
static void test_nl_file_numbers_simple_file(void)
{
    const char* input = "line1\nline2\n";
    char* in_path = create_temp_file_with(input);
    TEST_ASSERT_NOT_NULL(in_path);

    char* out_path = NULL;
    int saved_stdout = redirect_stdout_to_temp(&out_path);
    TEST_ASSERT_TRUE(saved_stdout >= 0);
    TEST_ASSERT_NOT_NULL(out_path);

    /* Call under test while stdout is redirected: no Unity asserts here. */
    bool ok = nl_file(in_path);

    /* Restore stdout before asserting. */
    restore_stdout(saved_stdout);

    /* Read captured output and assert. */
    char* out = read_entire_file(out_path);
    TEST_ASSERT_TRUE(ok);
    TEST_ASSERT_NOT_NULL(out);

    const char* expected = " 1\tline1\n 2\tline2\n";
    TEST_ASSERT_EQUAL_STRING(expected, out);

    free(out);
    unlink(out_path);
    free(out_path);
    unlink(in_path);
    free(in_path);
}

/* Test 2: Behavior with blank lines in 't' mode (number only non-empty lines). */
static void test_nl_file_t_mode_blank_lines(void)
{
    const char* input = "\nX\n\n";
    char* in_path = create_temp_file_with(input);
    TEST_ASSERT_NOT_NULL(in_path);

    /* Ensure 't' mode. */
    body_type = "t";
    current_type = body_type;
    reset_lineno();

    char* out_path = NULL;
    int saved_stdout = redirect_stdout_to_temp(&out_path);
    TEST_ASSERT_TRUE(saved_stdout >= 0);
    TEST_ASSERT_NOT_NULL(out_path);

    bool ok = nl_file(in_path);

    restore_stdout(saved_stdout);

    char* out = read_entire_file(out_path);
    TEST_ASSERT_TRUE(ok);
    TEST_ASSERT_NOT_NULL(out);

    const char* expected = "  \t\n 1\tX\n  \t\n";
    TEST_ASSERT_EQUAL_STRING(expected, out);

    free(out);
    unlink(out_path);
    free(out_path);
    unlink(in_path);
    free(in_path);
}

/* Test 3: Reading from stdin ("-") and have_read_stdin side-effect. */
static void test_nl_file_from_stdin_dash(void)
{
    const char* input = "a\nb\n";
    char* in_path = create_temp_file_with(input);
    TEST_ASSERT_NOT_NULL(in_path);

    /* Redirect stdin. */
    int saved_stdin = redirect_stdin_from_file(in_path);
    TEST_ASSERT_TRUE(saved_stdin >= 0);

    char* out_path = NULL;
    int saved_stdout = redirect_stdout_to_temp(&out_path);
    TEST_ASSERT_TRUE(saved_stdout >= 0);
    TEST_ASSERT_NOT_NULL(out_path);

    /* Call under test while stdout redirected. */
    bool ok = nl_file("-");

    /* Restore stdout and stdin before assertions. */
    restore_stdout(saved_stdout);
    dup2(saved_stdin, STDIN_FILENO);
    close(saved_stdin);

    char* out = read_entire_file(out_path);
    TEST_ASSERT_TRUE(ok);
    TEST_ASSERT_TRUE(have_read_stdin);
    TEST_ASSERT_NOT_NULL(out);

    const char* expected = " 1\ta\n 2\tb\n";
    TEST_ASSERT_EQUAL_STRING(expected, out);

    free(out);
    unlink(out_path);
    free(out_path);
    unlink(in_path);
    free(in_path);
}

/* Test 4: Nonexistent file should return false and not write to stdout. */
static void test_nl_file_nonexistent_returns_false(void)
{
    const char* bad_path = "/tmp/this_file_should_not_exist_nl_test_XXXX";
    /* Capture stdout (should be empty) and stderr (to avoid noisy output). */
    char* out_path = NULL;
    int saved_stdout = redirect_stdout_to_temp(&out_path);
    TEST_ASSERT_TRUE(saved_stdout >= 0);
    TEST_ASSERT_NOT_NULL(out_path);

    char* err_path = NULL;
    int saved_stderr = redirect_stderr_to_temp(&err_path);
    TEST_ASSERT_TRUE(saved_stderr >= 0);
    TEST_ASSERT_NOT_NULL(err_path);

    /* Call under test while redirected. */
    bool ok = nl_file(bad_path);

    /* Restore I/O before asserting. */
    restore_stdout(saved_stdout);
    restore_stderr(saved_stderr);

    /* stdout should be empty and ok should be false. */
    char* out = read_entire_file(out_path);
    TEST_ASSERT_FALSE(ok);
    TEST_ASSERT_NOT_NULL(out);
    TEST_ASSERT_EQUAL_STRING("", out);

    free(out);
    unlink(out_path);
    free(out_path);
    unlink(err_path);
    free(err_path);
}

/* Test 5: Starting line number and increment respected. */
static void test_nl_file_starting_and_increment(void)
{
    starting_line_number = 5;
    page_incr = 3;
    reset_numbers = true;
    reset_lineno();

    /* Keep 't' mode. */
    body_type = "t";
    current_type = body_type;

    const char* input = "aa\nbb\n";
    char* in_path = create_temp_file_with(input);
    TEST_ASSERT_NOT_NULL(in_path);

    char* out_path = NULL;
    int saved_stdout = redirect_stdout_to_temp(&out_path);
    TEST_ASSERT_TRUE(saved_stdout >= 0);
    TEST_ASSERT_NOT_NULL(out_path);

    bool ok = nl_file(in_path);

    restore_stdout(saved_stdout);

    char* out = read_entire_file(out_path);
    TEST_ASSERT_TRUE(ok);
    TEST_ASSERT_NOT_NULL(out);

    const char* expected = " 5\taa\n 8\tbb\n";
    TEST_ASSERT_EQUAL_STRING(expected, out);

    free(out);
    unlink(out_path);
    free(out_path);
    unlink(in_path);
    free(in_path);
}

/* Test 6: 'a' mode with blank_join > 1 numbers grouped blank lines appropriately. */
static void test_nl_file_a_mode_blank_join(void)
{
    /* Switch to 'a' mode and set blank_join. */
    body_type = "a";
    current_type = body_type;

    extern intmax_t blank_join; /* declared in program */
    blank_join = 2;

    reset_numbers = true;
    starting_line_number = 1;
    reset_lineno();

    const char* input = "\n\n\nx\n\n";
    char* in_path = create_temp_file_with(input);
    TEST_ASSERT_NOT_NULL(in_path);

    char* out_path = NULL;
    int saved_stdout = redirect_stdout_to_temp(&out_path);
    TEST_ASSERT_TRUE(saved_stdout >= 0);
    TEST_ASSERT_NOT_NULL(out_path);

    bool ok = nl_file(in_path);

    restore_stdout(saved_stdout);

    char* out = read_entire_file(out_path);
    TEST_ASSERT_TRUE(ok);
    TEST_ASSERT_NOT_NULL(out);

    /* Expected:
       blank -> no number
       second blank -> numbered "1"
       third blank -> no number
       'x' -> numbered "2"
       final blank -> no number
    */
    const char* expected =
        "  \t\n"
        " 1\t\n"
        "  \t\n"
        " 2\tx\n"
        "  \t\n";
    TEST_ASSERT_EQUAL_STRING(expected, out);

    free(out);
    unlink(out_path);
    free(out_path);
    unlink(in_path);
    free(in_path);
}

int main(void)
{
    UNITY_BEGIN();
    RUN_TEST(test_nl_file_numbers_simple_file);
    RUN_TEST(test_nl_file_t_mode_blank_lines);
    RUN_TEST(test_nl_file_from_stdin_dash);
    RUN_TEST(test_nl_file_nonexistent_returns_false);
    RUN_TEST(test_nl_file_starting_and_increment);
    RUN_TEST(test_nl_file_a_mode_blank_join);
    return UNITY_END();
}