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

/* The following globals/types are declared earlier in the cut.c TU and are used here:
   - struct field_range_pair
   - static unsigned char line_delim;
   - static char *output_delimiter_string;
   - static size_t output_delimiter_length;
   - static char output_delimiter_default[1];
   - extern struct field_range_pair *frp;
   - static void cut_bytes (FILE *stream);
*/

static int write_bytes(FILE *f, const void *buf, size_t len) {
    if (len == 0) return 0;
    size_t nw = fwrite(buf, 1, len, f);
    return (nw == len) ? 0 : -1;
}

static struct field_range_pair *make_frp(const uintmax_t (*pairs)[2], size_t n_pairs)
{
    /* Allocate n_pairs + 1 for a sentinel */
    struct field_range_pair *arr = (struct field_range_pair *)malloc((n_pairs + 1) * sizeof(*arr));
    TEST_ASSERT_NOT_NULL(arr);
    for (size_t i = 0; i < n_pairs; i++) {
        arr[i].lo = pairs[i][0];
        arr[i].hi = pairs[i][1];
    }
    /* Sentinel to avoid out-of-bounds access in helpers */
    arr[n_pairs].lo = UINTMAX_MAX;
    arr[n_pairs].hi = UINTMAX_MAX;
    return arr;
}

static void free_frp(struct field_range_pair *arr)
{
    free(arr);
}

static void set_output_delim_default(void)
{
    /* Make pointer-equality match default so cut_bytes inserts no delimiters between ranges */
    output_delimiter_string = output_delimiter_default;
    output_delimiter_length = 1; /* length value is not used when pointer == default */
}

static void set_output_delim_custom(const char *s)
{
    output_delimiter_string = (char *)s;
    output_delimiter_length = strlen(s);
}

/* Run cut_bytes on given input bytes with provided field range pairs.
   Capture stdout and compare to expected output. */
static void run_cut_bytes_case(const void *input, size_t in_len,
                               const uintmax_t (*ranges)[2], size_t n_ranges,
                               const void *expected, size_t exp_len,
                               unsigned char line_delim_ch)
{
    /* Configure line delimiter and ranges */
    line_delim = line_delim_ch;

    struct field_range_pair *saved_frp = frp;
    struct field_range_pair *arr = make_frp(ranges, n_ranges);
    frp = arr;

    /* Prepare input stream */
    FILE *in = tmpfile();
    TEST_ASSERT_NOT_NULL(in);
    if (write_bytes(in, input, in_len) != 0) {
        TEST_FAIL_MESSAGE("Failed to write input to tmpfile");
    }
    fflush(in);
    fseek(in, 0, SEEK_SET);

    /* Capture stdout */
    fflush(stdout);
    int saved_stdout_fd = dup(fileno(stdout));
    TEST_ASSERT_TRUE_MESSAGE(saved_stdout_fd >= 0, "dup(stdout) failed");

    FILE *cap = tmpfile();
    TEST_ASSERT_NOT_NULL(cap);
    int cap_fd = fileno(cap);
    TEST_ASSERT_TRUE_MESSAGE(cap_fd >= 0, "fileno(cap) failed");

    if (dup2(cap_fd, fileno(stdout)) < 0) {
        /* Can't use TEST_ASSERT while redirected; but we haven't redirected yet. */
        TEST_FAIL_MESSAGE("dup2 to redirect stdout failed");
    }

    /* Call function under test while stdout is redirected */
    cut_bytes(in);

    /* Flush and restore stdout BEFORE assertions */
    fflush(stdout);
    if (dup2(saved_stdout_fd, fileno(stdout)) < 0) {
        /* Now stdout points to capture; error handling minimal */
        /* Best effort: close and return */
    }
    close(saved_stdout_fd);

    /* Read captured output */
    fflush(cap);
    fseek(cap, 0, SEEK_END);
    long got_len_l = ftell(cap);
    TEST_ASSERT_TRUE_MESSAGE(got_len_l >= 0, "ftell on capture failed");
    size_t got_len = (size_t)got_len_l;
    fseek(cap, 0, SEEK_SET);

    char *got = (char *)malloc(got_len ? got_len : 1);
    TEST_ASSERT_NOT_NULL(got);
    size_t nr = fread(got, 1, got_len, cap);
    TEST_ASSERT_EQUAL_SIZE_T(got_len, nr);

    /* Close files */
    fclose(in);
    fclose(cap);

    /* Restore frp and free */
    frp = saved_frp;
    free_frp(arr);

    /* Assertions */
    TEST_ASSERT_EQUAL_SIZE_T(exp_len, got_len);
    if (exp_len == got_len) {
        TEST_ASSERT_EQUAL_UINT8_ARRAY(expected, got, exp_len);
    }
    free(got);
}

void setUp(void) {
    /* Default to newline-terminated lines and default output delimiter. */
    line_delim = '\n';
    set_output_delim_default();
}

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

/* Tests */

void test_cut_bytes_select_first_byte_simple_line(void)
{
    const char *input = "abcdef\n";
    const char *expected = "a\n";
    const uintmax_t ranges[][2] = { {1,1} };
    set_output_delim_default();
    run_cut_bytes_case(input, strlen(input),
                       ranges, 1,
                       expected, strlen(expected),
                       '\n');
}

void test_cut_bytes_multi_ranges_no_custom_delim(void)
{
    const char *input = "abcde\n";
    /* Select bytes 1 and 3-4; default output delimiter => no insertion */
    const char *expected = "acd\n";
    const uintmax_t ranges[][2] = { {1,1}, {3,4} };
    set_output_delim_default();
    run_cut_bytes_case(input, strlen(input),
                       ranges, 2,
                       expected, strlen(expected),
                       '\n');
}

void test_cut_bytes_multi_ranges_with_custom_delim(void)
{
    const char *input = "abcde\n";
    /* Select bytes 1 and 3-4, with custom delimiter ',' between discontiguous ranges */
    const char *expected = "a,cd\n";
    const uintmax_t ranges[][2] = { {1,1}, {3,4} };
    static const char comma[] = ",";
    set_output_delim_custom(comma);
    run_cut_bytes_case(input, strlen(input),
                       ranges, 2,
                       expected, strlen(expected),
                       '\n');
}

void test_cut_bytes_appends_newline_on_eof_without_newline(void)
{
    const char input[] = { 'a','b','c' }; /* No trailing newline */
    const char expected[] = { 'b','\n' }; /* Select byte 2; cut_bytes adds newline at EOF */
    const uintmax_t ranges[][2] = { {2,2} };
    set_output_delim_default();
    run_cut_bytes_case(input, sizeof(input),
                       ranges, 1,
                       expected, sizeof(expected),
                       '\n');
}

void test_cut_bytes_zero_terminated_lines(void)
{
    /* Two records: "ab\0" and "cde\0", select second byte of each record. */
    const char input[] = { 'a','b','\0','c','d','e','\0' };
    const char expected[] = { 'b','\0','d','\0' };
    const uintmax_t ranges[][2] = { {2,2} };
    set_output_delim_default();
    run_cut_bytes_case(input, sizeof(input),
                       ranges, 1,
                       expected, sizeof(expected),
                       '\0');
}

void test_cut_bytes_resets_between_lines_and_inserts_delim(void)
{
    /* Two lines: "abc\n" and "def\n", select bytes 1 and 3 with custom ":" between ranges.
       Expect "a:c\n" then "d:f\n". */
    const char *input = "abc\ndef\n";
    const char *expected = "a:c\nd:f\n";
    const uintmax_t ranges[][2] = { {1,1}, {3,3} };
    static const char colon[] = ":";
    set_output_delim_custom(colon);
    run_cut_bytes_case(input, strlen(input),
                       ranges, 2,
                       expected, strlen(expected),
                       '\n');
}

void test_cut_bytes_empty_input_produces_no_output(void)
{
    const char *input = "";
    const char *expected = "";
    const uintmax_t ranges[][2] = { {1,1} };
    set_output_delim_default();
    run_cut_bytes_case(input, 0,
                       ranges, 1,
                       expected, 0,
                       '\n');
}

int main(void)
{
    UNITY_BEGIN();
    RUN_TEST(test_cut_bytes_select_first_byte_simple_line);
    RUN_TEST(test_cut_bytes_multi_ranges_no_custom_delim);
    RUN_TEST(test_cut_bytes_multi_ranges_with_custom_delim);
    RUN_TEST(test_cut_bytes_appends_newline_on_eof_without_newline);
    RUN_TEST(test_cut_bytes_zero_terminated_lines);
    RUN_TEST(test_cut_bytes_resets_between_lines_and_inserts_delim);
    RUN_TEST(test_cut_bytes_empty_input_produces_no_output);
    return UNITY_END();
}