#include "set.h"
#include <ctype.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

bool insert_text(Set *set, char *restrict word, size_t *index) {
    if (*index > 0) {
        word[*index] = 0;
        if (!multiset_insert(set, word, *index + 1)) {
            fprintf(stderr, "Set insert failed.\n");
            return false;
        }
        *index = 0;
    }
    return true;
}

bool insert_words(FILE *fptr, Set *set) {
    static constexpr size_t buf_size = 4096;
    char buffer[buf_size];
    size_t bytes = 0;
    size_t word_size = buf_size;
    size_t index = 0;
    char *word = malloc(word_size + 1);
    if (word == nullptr) {
        fprintf(stderr, "Error on allocation.\n");
        return false;
    }
    while ((bytes = fread(buffer, sizeof(char), buf_size, fptr)) > 0) {
        for (size_t i = 0; i < bytes; ++i) {
            unsigned char c = (unsigned char)buffer[i];
            if (isalnum(c)) {
                if (index >= word_size) {
                    word_size *= 2;
                    char *temp = realloc(word, word_size + 1);
                    if (temp == nullptr) {
                        free(word);
                        return false;
                    }
                    word = temp;
                }
                word[index++] = (char)tolower(c);
            } else {

                if (!insert_text(set, word, &index)) {
                    free(word);
                    return false;
                }
            }
        }
    }
    if (ferror(fptr)) {
        free(word);
        return false;
    }
    if (index > 0) {
        word[index] = 0;
        if (!insert_text(set, word, &index)) {
            free(word);
            return false;
        }
    }
    free(word);
    return true;
}

void destroy(void *ptr) {
    free(ptr);
}

int compare(const void *a, const void *b) {
    if (a == nullptr && b == nullptr)
        return 0;

    if (a == nullptr)
        return -1;
    if (b == nullptr)
        return 1;
    return strcmp((const char *)a, (const char *)b);
}

void echo(const void *ptr) {
    printf("\t%s\n", (const char *)ptr);
}

void echo_count(const void *ptr, size_t count) {
    printf("\t%s: %zu\n", (const char *)ptr, count);
}

void echo_notab(const void *ptr) {
    printf("%s\n", (const char *)ptr);
}

int main(int argc, char **argv) {

    if (argc > 1) {
        size_t files = 0;
        Set *total = nullptr;
        bool show_info = true;
        bool use_multi = false;
        int start = 1;
        int file_index = 1;
        if (strcmp(argv[1], "-q") == 0) {
            show_info = false;
            start++;
        } else if (strcmp(argv[1], "-m") == 0) {
            use_multi = true;
            show_info = true;
            start++;
        } else if (strcmp(argv[1], "-mq") == 0) {
            show_info = false;
            use_multi = true;
            start++;
        }
        if (!set_init(&total, destroy, compare)) {
            fprintf(stderr, "Error creating set..\n");
            return EXIT_FAILURE;
        }
        for (int i = start; i < argc; ++i) {
            FILE *fptr = fopen(argv[i], "rb");
            if (fptr == nullptr) {
                if (show_info)
                    fprintf(stderr, "Error file: %s could not be opened.\n", argv[i]);
                continue;
            }

            Set *temp_set = nullptr;
            if (!set_init(&temp_set, destroy, compare)) {
                fprintf(stderr, "Error initializing set.\n");
                set_free(total);
                fclose(fptr);
                return EXIT_FAILURE;
            }

            if (insert_words(fptr, temp_set)) {
                if (!multiset_concat(total, temp_set)) {
                    fprintf(stderr, "Error inserting set into total.\n");
                    set_free(total);
                    set_free(temp_set);
                    fclose(fptr);
                    return EXIT_FAILURE;
                } else {
                    set_free(temp_set);
                }
                if (show_info) {
                    printf("Processed file[%d] ->  %s.\n", file_index, argv[i]);
                    file_index++;
                }
                files++;
            } else {
                set_free(total);
                set_free(temp_set);
                fclose(fptr);
                return EXIT_FAILURE;
            }
            fclose(fptr);
        }
        if (show_info)
            printf("Unique words across all files: {\n");
        if (use_multi)
            multiset_print(total, echo_count);
        else
            set_print(total, (show_info == true) ? echo : echo_notab);
        if (show_info) {
            printf("}\n");
            printf("%zu total unique words across %zu files.\n", set_count(total), files);
        }
        set_free(total);
    }
    return EXIT_SUCCESS;
}