#include "hashmap.h"
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define INPUT_BUF_SIZE 1024

const char HASHMAPP_MAGIC[] = "HSMP";

typedef struct AppState {
    char running;
    HashMap map;
} AppState;

void open_file(HashMap *map, const char *filename) {
    FILE *file = fopen(filename, "r");
    if (file == NULL) {
        fprintf(stderr, "failed to open file: %s\n", strerror(errno));
        return;
    }

    fseek(file, 0, SEEK_END);
    long filesize = ftell(file);
    fseek(file, 0, SEEK_SET);
    if (filesize < 4) {
        fprintf(stderr, "invalid file: %s\n", filename);
        return;
    }

    int magic_len = strlen(HASHMAPP_MAGIC);
    char magic[magic_len + 1];
    unsigned long cur = ftell(file);
    fread(magic, magic_len, 1, file);
    magic[magic_len] = 0;
    if (strcmp(HASHMAPP_MAGIC, magic) != 0) {
        fprintf(stderr, "invalid file: %s\n", filename);
        return;
    }

    while (cur < filesize) {
        uint16_t key_len = 0;
        fread(&key_len, sizeof(uint16_t), 1, file);
        char key[key_len + 1];
        fread(key, key_len, 1, file);
        key[key_len] = 0;

        uint16_t data_size = 0;
        fread(&data_size, sizeof(uint16_t), 1, file);
        char *data = malloc(data_size);
        fread(data, data_size, 1, file);
        data[data_size] = 0;

        map_set(map, key, data, data_size);

        cur = ftell(file);
    }

    if (fclose(file) != 0) {
        fprintf(stderr, "failed to close file: %s\n", strerror(errno));
        return;
    }

    printf("opened db: %s\n", filename);
}

void write_file(HashMap *map, const char *filename) {
    FILE *file = fopen(filename, "w+");
    if (file == NULL) {
        fprintf(stderr, "failed to open file: %s\n", strerror(errno));
        return;
    }

    int fd = fileno(file);
    if (fd == -1) {
        fprintf(stderr, "failed to get descriptor: %s\n", strerror(errno));
        fclose(file);
        return;
    }

    unsigned long offset = 0;
    offset += fwrite(HASHMAPP_MAGIC, strlen(HASHMAPP_MAGIC), 1, file);

    for (uint16_t bucket_i = 0; bucket_i < HASHMAP_BUCKETS; bucket_i++) {
        Bucket *bucket = &map->buckets[bucket_i];
        for (uint16_t i = 0; i < bucket->n_entries; i++) {
            Entry *entry = &bucket->entries[i];
            uint16_t key_len = strlen(entry->key);
            uint16_t data_len = strlen(entry->data);
            offset += fwrite(&key_len, sizeof(uint16_t), 1, file);
            offset += fwrite(entry->key, strlen(entry->key), 1, file);
            offset += fwrite(&data_len, sizeof(uint16_t), 1, file);
            offset += fwrite(entry->data, strlen(entry->data), 1, file);
        }
    }

    if (ftruncate(fd, offset) != 0) {
        fprintf(stderr, "failed to truncate file: %s\n", strerror(errno));
        fclose(file);
        return;
    }
    if (fclose(file) != 0) {
        fprintf(stderr, "failed to close file: %s\n", strerror(errno));
        return;
    }

    printf("written db to \"%s\" successfully.\n", filename);
}

void handle_command(AppState *app, char *buf, size_t buf_len) {
    if (!strcmp(buf, "q"))
        app->running = 0;
    else if (strcmp(buf, "w ") > 0)
        write_file(&app->map, buf + 2);
    else if (strcmp(buf, "o ") > 0)
        open_file(&app->map, buf + 2);
    else
        printf("?\n");
}

int main(int argc, char *argv[]) {
    printf("hashmapp. the map to app all hashes. wait-\n"
        "\":q\" to exit\n"
        "\":w <file>\" to save\n"
        "\":o <file>\" to load\n\n");

    AppState app = { 0 };
    init_map(&app.map);

    char buf[INPUT_BUF_SIZE];
    app.running = 1;
    while (app.running) {
        memset(buf, 0, INPUT_BUF_SIZE);

        printf("> ");
        if (fgets(buf, INPUT_BUF_SIZE, stdin) == NULL) {
            fprintf(stderr, "failed to read stdin: %u\n", errno);
            return EXIT_FAILURE;
        }
        size_t buf_len = strnlen(buf, INPUT_BUF_SIZE);
        buf[buf_len - 1] = 0;

        if (buf_len == 0)
            continue;

        if (buf[0] == ':') {
            if (buf_len < 2) {
                printf("?\n");
                continue;
            }

            handle_command(&app, buf + 1, buf_len - 1);
            continue;
        }

        char *eq = strchr(buf, '=');
        if (eq == NULL) {
            void *data = map_get(&app.map, buf);
            if (data == NULL)
                printf("\n");
            else
                printf("%s\n", (char*)data);

            continue;
        }
        
        uint16_t key_len = eq - buf + 1;
        char key[key_len];
        strncpy(key, buf, key_len);
        key[key_len - 1] = 0;

        uint16_t value_len = strlen(buf + key_len);
        char *value = malloc(sizeof(char) * value_len);
        strncpy(value, buf + key_len, value_len);
        value[value_len] = 0;

        map_set(&app.map, key, value, value_len);
    }

    for (size_t bucket_i = 0; bucket_i < HASHMAP_BUCKETS; bucket_i++) {
        Bucket *bucket = &app.map.buckets[bucket_i];
        for (size_t i = 0; i < bucket->n_entries; i++) {
            free(bucket->entries[i].key);
            free(bucket->entries[i].data);
        }
    }

    return EXIT_SUCCESS;
}