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

/* The test file is included after the program source, so we can access
   internal symbols directly. We will set up the global state to drive
   flush_paragraph(). */

/* Prototypes for functions under test (already defined above in the TU). */
/* static void flush_paragraph(void);  -- available since included before */

/* Globals from the program under test (declared earlier in same TU). */
extern char parabuf[];           /* paragraph character buffer */
extern char *wptr;               /* first unused char position in parabuf */
extern int max_width;            /* maximum line width */
extern int goal_width;           /* preferred goal width */
extern int first_indent;         /* indentation first line */
extern int other_indent;         /* indentation other lines */
extern int last_line_length;     /* used by fmt_paragraph */
extern int prefix_indent;        /* prefix indent for current paragraph */
extern char const *prefix;       /* prefix string */
extern int prefix_length;        /* prefix length (trimmed) */
extern int prefix_full_length;   /* prefix full length */
extern int prefix_lead_space;    /* prefix leading spaces */
extern int out_column;           /* output column tracker */
extern int tabs;                 /* whether tabs can be used */

/* Word array and pointer. Note: 'word' is a macro-renamed identifier in
   the main file, but our references will be preprocessed consistently. */
extern struct Word; /* forward reference for type completeness */
extern __typeof__(((struct Word*)0)->length) dummy_len_for_type; /* ensure type loaded */
extern __typeof__(((struct Word*)0)) dummy_word_type;            /* ensure struct visible */
extern struct Word *word_limit;
extern struct Word word[];

/* Helper: redirect stdout to a temporary file; returns 0 on success. */
static int redirect_stdout_start(char *path_buf, size_t path_buf_sz, FILE **cap_fp, int *saved_fd)
{
    if (!path_buf || path_buf_sz < 32 || !cap_fp || !saved_fd) return -1;
    snprintf(path_buf, path_buf_sz, "/tmp/fmt_flush_paragraph_XXXXXX");
    int fd = mkstemp(path_buf);
    if (fd < 0) return -1;
    FILE *fp = fdopen(fd, "w+");
    if (!fp) {
        close(fd);
        return -1;
    }
    fflush(stdout);
    *saved_fd = dup(fileno(stdout));
    if (*saved_fd < 0) {
        fclose(fp);
        unlink(path_buf);
        return -1;
    }
    if (dup2(fd, fileno(stdout)) < 0) {
        close(*saved_fd);
        fclose(fp);
        unlink(path_buf);
        return -1;
    }
    *cap_fp = fp;
    return 0;
}

/* Helper: restore stdout; leaves cap_fp open for reading. */
static void redirect_stdout_end(FILE *cap_fp, int saved_fd)
{
    fflush(stdout);
    if (saved_fd >= 0) {
        dup2(saved_fd, fileno(stdout));
        close(saved_fd);
    }
    fflush(stdout);
    (void)cap_fp; /* still open for caller to read */
}

/* Convenience: reset globals to a clean baseline for tests. */
static void reset_globals_defaults(void)
{
    /* No prefix, no indentation, no tabs. */
    prefix = "";
    prefix_length = 0;
    prefix_full_length = 0;
    prefix_lead_space = 0;
    prefix_indent = 0;
    first_indent = 0;
    other_indent = 0;
    out_column = 0;
    last_line_length = 0;
    tabs = 0;

    /* Set widths; goal equals max for stable behavior. */
    max_width = 12;
    goal_width = 12;

    /* Clear buffer and pointers. */
    wptr = parabuf;
}

/*--- Unity setUp/tearDown ---*/
void setUp(void) {
    reset_globals_defaults();
}

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

/* Test 1: Special case where word_limit == word; flush_paragraph should
   write the entire parabuf to stdout and reset wptr to parabuf. */
void test_flush_paragraph_single_chunk_no_words(void)
{
    /* Prepare parabuf with raw bytes. */
    const char *payload = "XYZ";
    memcpy(parabuf, payload, 3);
    wptr = parabuf + 3;

    /* Set word_limit to point to the start: no complete words present. */
    word_limit = word; /* word == first element; indicates zero words */

    char path[64];
    FILE *cap = NULL; int saved = -1;

    TEST_ASSERT_EQUAL_INT(0, redirect_stdout_start(path, sizeof(path), &cap, &saved));

    /* Do not use TEST_ASSERT while stdout is redirected. */
    flush_paragraph();

    redirect_stdout_end(cap, saved);

    /* Read captured output and verify. */
    fseek(cap, 0, SEEK_SET);
    char buf[32] = {0};
    size_t n = fread(buf, 1, sizeof(buf), cap);
    fclose(cap);

    /* Cleanup the file. */
    unlink(path);

    TEST_ASSERT_EQUAL_size_t(3, n);
    TEST_ASSERT_EQUAL_UINT8_ARRAY(payload, buf, 3);

    /* wptr should be reset to the start of parabuf. */
    TEST_ASSERT_EQUAL_PTR(parabuf, wptr);
}

/* Helper to initialize a simple 3-word paragraph with 5-char words and
   1-space gaps, designed so the optimal split is after the 2nd word. */
static void init_three_word_paragraph(void)
{
    /* Words: "aaaaa" "bbbbb" "ccccc" */
    const char *w1 = "aaaaa";
    const char *w2 = "bbbbb";
    const char *w3 = "ccccc";

    /* Place texts contiguously in parabuf. */
    char *p = parabuf;
    memcpy(p, w1, 5); word[0].text = p; word[0].length = 5; p += 5;
    memcpy(p, w2, 5); word[1].text = p; word[1].length = 5; p += 5;
    memcpy(p, w3, 5); word[2].text = p; word[2].length = 5; p += 5;
    wptr = p;

    /* Set inter-word spaces to 1; flags to non-punctuation, non-final. */
    word[0].space = 1; word[0].paren = 0; word[0].period = 0; word[0].punct = 0; word[0].final = 0;
    word[1].space = 1; word[1].paren = 0; word[1].period = 0; word[1].punct = 0; word[1].final = 0;
    word[2].space = 1; word[2].paren = 0; word[2].period = 0; word[2].punct = 0; word[2].final = 0;

    /* Three complete words. */
    word_limit = word + 3;

    /* Width settings ensure that only two words (5 + 1 + 5 = 11) fit on a line. */
    max_width = 12;
    goal_width = 12;
    first_indent = 0;
    other_indent = 0;
    last_line_length = 0;
    prefix = "";
    prefix_length = 0;
    prefix_full_length = 0;
    prefix_indent = 0;
    tabs = 0;
}

/* Test 2: Multi-word paragraph split and compaction. After flush_paragraph,
   verify that the first two words are output as one line, and the remaining
   word is compacted to the front of parabuf and word array updated. */
void test_flush_paragraph_split_and_compact(void)
{
    init_three_word_paragraph();

    char path[64];
    FILE *cap = NULL; int saved = -1;

    TEST_ASSERT_EQUAL_INT(0, redirect_stdout_start(path, sizeof(path), &cap, &saved));

    /* Avoid Unity asserts while redirected. */
    flush_paragraph();

    redirect_stdout_end(cap, saved);

    /* Read captured output. */
    fseek(cap, 0, SEEK_SET);
    char outbuf[128] = {0};
    size_t n = fread(outbuf, 1, sizeof(outbuf), cap);
    fclose(cap);
    unlink(path);

    /* Should have printed the first line with two words and a newline. */
    const char *expected_line = "aaaaa bbbbb\n";
    size_t expected_len = strlen(expected_line);
    TEST_ASSERT_TRUE(n >= expected_len);
    TEST_ASSERT_EQUAL_MEMORY(expected_line, outbuf, expected_len);

    /* Buffer should now contain only the remaining word "ccccc". */
    TEST_ASSERT_EQUAL_INT(5, (int)(wptr - parabuf));
    TEST_ASSERT_EQUAL_MEMORY("ccccc", parabuf, 5);

    /* Word array should now start with the third word, and word_limit reduced. */
    TEST_ASSERT_EQUAL_PTR(word + 1, word_limit);
    TEST_ASSERT_EQUAL_INT(5, word[0].length);
    TEST_ASSERT_EQUAL_MEMORY("ccccc", word[0].text, 5);
    TEST_ASSERT_EQUAL_INT(1, word[0].space);
}

int main(void)
{
    UNITY_BEGIN();
    RUN_TEST(test_flush_paragraph_single_chunk_no_words);
    RUN_TEST(test_flush_paragraph_split_and_compact);
    return UNITY_END();
}