/* ----------------------------------------------------------------------------
 * --  _____       ______  _____                                              -
 * -- |_   _|     |  ____|/ ____|                                             -
 * --   | |  _ __ | |__  | (___    Institute of Embedded Systems              -
 * --   | | | '_ \|  __|  \___ \   Zuercher Hochschule Winterthur             -
 * --  _| |_| | | | |____ ____) |  (University of Applied Sciences)           -
 * -- |_____|_| |_|______|_____/   8401 Winterthur, Switzerland               -
 * ----------------------------------------------------------------------------
 */
/**
 * @file
 * @brief Implementation of the test_utils.
 */
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <unistd.h>
#include <errno.h>
#include <assert.h>
#include "CUnit/Basic.h"
#include "test_utils.h"

int file_exists(const char file_path[])
{
    // preconditions
    assert(file_path);
    int errno_safe = errno;
    errno = 0;
    // try and forgive...
    FILE *file = fopen(file_path, "r");
    assert(file || (!file && (errno == ENOENT))); // either it exists or "No such file or directory" error code (see man errno).
    errno = errno_safe; // fopen will set errno if the file does not exist
    if (file) {
        assert(0 == fclose(file));
        return 1; // existed
    }
    return 0; // did not exist
}

void remove_file_if_exists(const char file_path[])
{
    // we take the risk that between checking and removing, some undesired file access may happen and jeopardize the control logic...
    if (file_exists(file_path)) {
        assert(0 == unlink(file_path));
    }
}

void assert_lines(const char file[], const char *lines[], size_t n_lines)
{
    // preconditions
    CU_ASSERT_PTR_NOT_NULL_FATAL(file);
    CU_ASSERT_PTR_NOT_NULL_FATAL(lines);

    // file access may always fail
    FILE *input = fopen(file, "r");
    if (!input) perror(file);
    CU_ASSERT_PTR_NOT_NULL_FATAL(input);

    // process all lines and compare to the file content
    size_t i = 0;
    size_t n = 0;
    for(i = 0; i < n_lines && n == 0; i++) {
        const char *line = lines[i];
        CU_ASSERT_PTR_NOT_NULL(line);
        if (line) {
            size_t len = n = strlen(line);
            CU_ASSERT(n > 0);
            while (n > 0) {
                int c = fgetc(input);
                CU_ASSERT_FALSE(feof(input));
                CU_ASSERT_EQUAL(c, *line);
                if (c != *line) {
                    printf("\nfile %s: line %zu, pos %zu = %d = '%c', expected = %d = '%c'\n",
                           file, i+1, len-n+1, c, isprint(c) ? c : '.', *line, isprint(*line) ? *line : '.');
                    break;
                }
                line++;
                n--;
            }
        }
    }
    CU_ASSERT_FALSE(feof(input));
    (void)fgetc(input);
    CU_ASSERT_TRUE(feof(input));
    CU_ASSERT_EQUAL(i, n_lines);
    CU_ASSERT_EQUAL(n, 0);

    // successfully reached the end...
    int fclose_result = fclose(input);
    CU_ASSERT(0 == fclose_result);

    // print actual versus expected in case of error
    if (n != 0 || i != n_lines) {
        printf("---- EXPECTED ----\n");
        for(int i = 0; i < n_lines; i++) {
            const char *p = lines[i];
            while(p && *p) {
                putchar(*p);
                p++;
            }
        }
        printf("---- ACTUAL (%s) ----\n", file);
        FILE* fd = fopen(file, "r");
        int last = 0;
        while(fd && !feof(fd)) {
            int c = fgetc(fd);
            if (c != EOF) {
                last = c;
                putchar(c);
            }
        }
        if (fd) fclose(fd);
        if (last != '\n') putchar('\n');
        printf("---- END ----\n");
    }

}