/*
 * Compilar com: gcc -Wall hdoc.c messages.c -o hdoc
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "messages.h"

typedef enum {
    OPT_ERROR = -1,
    OPT_NAME,
    OPT_OVERWRITE,
    OPT_APPEND,
    OPT_HELP
} Option;

int parse_arg(char *arg);

int main(int argc, char **argv) {
    char *file = NULL;
    char *mode = NULL;

    if (argc == 2) {
        switch (parse_arg(argv[1])) {
            case OPT_HELP:
                return print_usage(EXIT_SUCCESS, argv[0]);
            case OPT_NAME:
                if (access(argv[1], F_OK) == 0) {
                    return print_error_usage(MSG_FILE_EXISTS, argv[0]);
                }
                file = argv[1];
                mode = "w";
                break;
            default:
                return print_error_usage(MSG_INVALID_ARG, argv[0]);
        }
    } else if (argc == 3) {
        for (int i = 1; argv[i] != NULL; i++) {
            switch (parse_arg(argv[i])) {
                case OPT_NAME:
                    if (file == NULL) file = argv[i];
                    break;
                case OPT_OVERWRITE:
                    if (mode == NULL) mode = "w";
                    break;
                case OPT_APPEND:
                    if (mode == NULL) mode = "a";
                    break;
                case OPT_HELP:
                    return print_usage(EXIT_SUCCESS, argv[0]);
                case OPT_ERROR:
                    print_error_fmt(MSG_INVALID_FMT, argv[i]);
                    return print_usage(EXIT_FAILURE, argv[0]);
            }
        }
        if (file == NULL || mode == NULL) {
            return print_error_usage(MSG_INCORRECT_ALL, argv[0]);
        }
    } else {
        return print_error_usage(MSG_ARGC_ERROR, argv[0]);
    }
    
    FILE *fstr = fopen(file, mode);
    if (!fstr) {
        perror(MSG_FOPEN_ERROR);
        return EXIT_FAILURE;
    }
    char line[BUFSIZ];
    puts(MSG_EOF_HINT);
    while (1) {
        if (fgets(line, BUFSIZ, stdin) == NULL) break;
        fprintf(fstr, "%s", line);
    }
    fclose(fstr);

    return EXIT_SUCCESS;
}

int parse_arg(char *arg) {
    // Argumento iniciado com '-'...
    if (arg[0] == '-') {
        if (strcmp(arg, "-a") == 0) {
            return OPT_APPEND;
        } else if (strcmp(arg, "-o") == 0) {
            return OPT_OVERWRITE;
        } else if (strcmp(arg, "-h") == 0) {
            return OPT_HELP;
        } else {
            // Argumento inválido!
            return OPT_ERROR;
        }
    }
    // Sem traço é nome de arquivo...
    return OPT_NAME;
}