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

/* Helper to free any existing outlist entries and reset to defaults. */
static void clear_outlist(void)
{
    /* outlist_head and outlist_end are defined in the program under test. */
    while (outlist_head.next) {
        struct outlist *tmp = outlist_head.next;
        outlist_head.next = tmp->next;
        free(tmp);
    }
    outlist_end = &outlist_head;
}

/* Reset relevant globals to safe defaults before each test. */
static void reset_join_state(void)
{
    /* Output formatting */
    output_separator = " ";
    output_seplen = 1;
    empty_filler = NULL;

    /* Field separators: default to blanks (tab.len == 0) */
    tab.ch = 0;
    tab.len = 0;

    /* Behavior flags */
    ignore_case = false;
    hard_LC_COLLATE = false;
    autoformat = false;
    join_header_lines = false;
    print_pairables = true;
    print_unpairables_1 = false;
    print_unpairables_2 = false;
    seen_unpairable = false;
    issued_disorder_warning[0] = false;
    issued_disorder_warning[1] = false;
    /* Default input-order checking behavior */
    check_input_order = CHECK_ORDER_DEFAULT;

    /* Join fields: use the first field (index 0) in both files */
    join_field_1 = 0;
    join_field_2 = 0;

    /* Line tracking and buffers */
    prevline[0] = NULL;
    prevline[1] = NULL;
    line_no[0] = 0;
    line_no[1] = 0;
    spareline[0] = NULL;
    spareline[1] = NULL;

    /* EOL */
    eolchar = '\n';

    /* Clear any outlist configuration */
    clear_outlist();

    /* Optional: set input names (only used in diagnostics) */
    g_names[0] = (char *)"f1";
    g_names[1] = (char *)"f2";
}

/* Create a temporary stream loaded with 'data'. */
static FILE* make_stream_from_str(const char* data)
{
    FILE* f = tmpfile();
    if (!f) return NULL;
    size_t len = strlen(data);
    if (len > 0) {
        if (fwrite(data, 1, len, f) != len) {
            fclose(f);
            return NULL;
        }
    }
    rewind(f);
    return f;
}

/* Capture stdout while calling join(fp1, fp2). Returns malloc'd buffer with output or NULL on error. */
static char* capture_join_output(FILE* fp1, FILE* fp2)
{
    fflush(stdout);
    int saved_stdout = dup(STDOUT_FILENO);
    if (saved_stdout < 0) {
        return NULL;
    }

    FILE* cap = tmpfile();
    if (!cap) {
        close(saved_stdout);
        return NULL;
    }
    int cap_fd = fileno(cap);
    if (cap_fd < 0) {
        fclose(cap);
        close(saved_stdout);
        return NULL;
    }

    if (dup2(cap_fd, STDOUT_FILENO) < 0) {
        fclose(cap);
        close(saved_stdout);
        return NULL;
    }

    /* Call the function under test. Do not use Unity asserts while stdout is redirected. */
    join(fp1, fp2);

    /* Flush and collect the output. */
    fflush(stdout);
    fflush(cap);
    if (fseek(cap, 0, SEEK_END) != 0) {
        /* Restore stdout before returning */
        dup2(saved_stdout, STDOUT_FILENO);
        close(saved_stdout);
        fclose(cap);
        return NULL;
    }
    long sz = ftell(cap);
    if (sz < 0) {
        dup2(saved_stdout, STDOUT_FILENO);
        close(saved_stdout);
        fclose(cap);
        return NULL;
    }
    rewind(cap);

    char* buf = (char*)malloc((size_t)sz + 1);
    if (!buf) {
        dup2(saved_stdout, STDOUT_FILENO);
        close(saved_stdout);
        fclose(cap);
        return NULL;
    }
    size_t rd = fread(buf, 1, (size_t)sz, cap);
    buf[rd] = '\0';

    /* Restore stdout. */
    dup2(saved_stdout, STDOUT_FILENO);
    close(saved_stdout);
    fclose(cap);

    return buf;
}

void setUp(void) {
    reset_join_state();
}
void tearDown(void) {
    /* Nothing special; outlist cleared in setUp */
}

/* Test 1: Basic pairable join, default whitespace-separated fields. */
void test_join_basic_pairables(void)
{
    const char* s1 = "a 1\nb 2\n";
    const char* s2 = "a x\nb y\n";

    FILE* f1 = make_stream_from_str(s1);
    FILE* f2 = make_stream_from_str(s2);
    TEST_ASSERT_NOT_NULL(f1);
    TEST_ASSERT_NOT_NULL(f2);

    print_pairables = true;
    join_field_1 = 0;
    join_field_2 = 0;

    char* out = capture_join_output(f1, f2);

    fclose(f1);
    fclose(f2);

    TEST_ASSERT_NOT_NULL(out);
    TEST_ASSERT_EQUAL_STRING("a 1 x\nb 2 y\n", out);
    free(out);
}

/* Test 2: Print unpairable lines from file1. */
void test_join_unpairables_file1(void)
{
    const char* s1 = "a 1\nb 2\nc 3\n";
    const char* s2 = "a x\nb y\n";

    FILE* f1 = make_stream_from_str(s1);
    FILE* f2 = make_stream_from_str(s2);
    TEST_ASSERT_NOT_NULL(f1);
    TEST_ASSERT_NOT_NULL(f2);

    print_pairables = true;
    print_unpairables_1 = true;
    join_field_1 = 0;
    join_field_2 = 0;

    char* out = capture_join_output(f1, f2);

    fclose(f1);
    fclose(f2);

    TEST_ASSERT_NOT_NULL(out);
    TEST_ASSERT_EQUAL_STRING("a 1 x\nb 2 y\nc 3\n", out);
    free(out);
}

/* Test 3: Multiple matches cross-product */
void test_join_multiple_matches_cross_product(void)
{
    const char* s1 = "a 1\na 2\n";
    const char* s2 = "a x\na y\n";

    FILE* f1 = make_stream_from_str(s1);
    FILE* f2 = make_stream_from_str(s2);
    TEST_ASSERT_NOT_NULL(f1);
    TEST_ASSERT_NOT_NULL(f2);

    print_pairables = true;

    char* out = capture_join_output(f1, f2);

    fclose(f1);
    fclose(f2);

    TEST_ASSERT_NOT_NULL(out);
    /* Expected order: (1,x), (1,y), (2,x), (2,y) */
    TEST_ASSERT_EQUAL_STRING("a 1 x\na 1 y\na 2 x\na 2 y\n", out);
    free(out);
}

/* Test 4: Header-line handling with autoformat */
void test_join_header_and_autoformat(void)
{
    const char* s1 = "ID A\n1 AA\n2 BB\n";
    const char* s2 = "ID B\n1 XX\n3 YY\n";

    FILE* f1 = make_stream_from_str(s1);
    FILE* f2 = make_stream_from_str(s2);
    TEST_ASSERT_NOT_NULL(f1);
    TEST_ASSERT_NOT_NULL(f2);

    join_header_lines = true;
    autoformat = true;
    print_pairables = true;

    char* out = capture_join_output(f1, f2);

    fclose(f1);
    fclose(f2);

    TEST_ASSERT_NOT_NULL(out);
    /* Header line, then only the pairable 1 */
    TEST_ASSERT_EQUAL_STRING("ID A B\n1 AA XX\n", out);
    free(out);
}

/* Test 5: Case-insensitive join */
void test_join_ignore_case(void)
{
    const char* s1 = "A 1\n";
    const char* s2 = "a x\n";

    FILE* f1 = make_stream_from_str(s1);
    FILE* f2 = make_stream_from_str(s2);
    TEST_ASSERT_NOT_NULL(f1);
    TEST_ASSERT_NOT_NULL(f2);

    ignore_case = true;
    print_pairables = true;

    char* out = capture_join_output(f1, f2);

    fclose(f1);
    fclose(f2);

    TEST_ASSERT_NOT_NULL(out);
    TEST_ASSERT_EQUAL_STRING("A 1 x\n", out);
    free(out);
}

/* Test 6: Empty field with filler using tab as the field separator */
void test_join_empty_field_with_filler_and_tab(void)
{
    const char* s1 = "a\t\t1\n";  /* fields: "a", "", "1" */
    const char* s2 = "a\tx\n";    /* fields: "a", "x" */

    FILE* f1 = make_stream_from_str(s1);
    FILE* f2 = make_stream_from_str(s2);
    TEST_ASSERT_NOT_NULL(f1);
    TEST_ASSERT_NOT_NULL(f2);

    /* Configure tab as the input separator, ensure output sep is space. */
    tab.ch = '\t';
    tab.len = 1;
    empty_filler = "<>";
    print_pairables = true;

    char* out = capture_join_output(f1, f2);

    fclose(f1);
    fclose(f2);

    TEST_ASSERT_NOT_NULL(out);
    /* Expect filler for the empty field */
    TEST_ASSERT_EQUAL_STRING("a <> 1 x\n", out);
    free(out);
}

/* Test 7: Custom outlist: select specific fields */
void test_join_custom_outlist_selection(void)
{
    const char* s1 = "a 1 2\n";
    const char* s2 = "a 3 4\n";

    FILE* f1 = make_stream_from_str(s1);
    FILE* f2 = make_stream_from_str(s2);
    TEST_ASSERT_NOT_NULL(f1);
    TEST_ASSERT_NOT_NULL(f2);

    print_pairables = true;

    /* Configure outlist: file2 field index 2 ("4"), then join field (0), then file1 field index 1 ("2") */
    add_field(2, 2);
    add_field(0, 0);
    add_field(1, 1);

    char* out = capture_join_output(f1, f2);

    fclose(f1);
    fclose(f2);

    TEST_ASSERT_NOT_NULL(out);
    TEST_ASSERT_EQUAL_STRING("4 a 2\n", out);
    free(out);
}

int main(void)
{
    UNITY_BEGIN();

    RUN_TEST(test_join_basic_pairables);
    RUN_TEST(test_join_unpairables_file1);
    RUN_TEST(test_join_multiple_matches_cross_product);
    RUN_TEST(test_join_header_and_autoformat);
    RUN_TEST(test_join_ignore_case);
    RUN_TEST(test_join_empty_field_with_filler_and_tab);
    RUN_TEST(test_join_custom_outlist_selection);

    return UNITY_END();
}