/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 * -----------------------------------------------------------------------------
 * File: HashTable.c
 * Description:
 *  This file contains the functions for modifying the Hash Table. It includes functions 
 *  to get, Insert, Remove, check if has key and check if empty. 
 * 
 * Author: Mineplay
 * -----------------------------------------------------------------------------
 */
#include "../../Include/Fledasty/Core/HashTable.h"

#include <Hallocy/Core/Allocator.h>
#include <Hallocy/Core/Memory.h>
#include <Hallocy/Utils/Error.h>

static const int FLEDASTY_HASH_TABLE_SIZE_THRESHOLD = 75;

FledastyError fledasty_hash_table_initialize(FledastyHashTable *new_hash_table, const size_t key_byte_size, const size_t value_byte_size, size_t (*hash_function)(const void *key)) {
    if (new_hash_table == NULL || hash_function == NULL) {
        return FLEDASTY_ERROR_INVALID_POINTER;
    }

    new_hash_table->key_byte_size = key_byte_size;
    new_hash_table->value_byte_size = value_byte_size;
    new_hash_table->hash_function = hash_function;

    new_hash_table->size = 0;
    new_hash_table->capacity = 1024;
    new_hash_table->Table = (FledastyDynamicArray*)hallocy_calloc(sizeof(FledastyDynamicArray), new_hash_table->capacity);
    if (new_hash_table->Table == NULL) {
        return FLEDASTY_ERROR_FAILED_ALLOCATION;
    }

    return FLEDASTY_ERROR_NONE;
}

FledastyError fledasty_hash_table_destroy(FledastyHashTable *current_hash_table) {
    if (current_hash_table == NULL) {
        return FLEDASTY_ERROR_INVALID_POINTER;
    }

    for (size_t i = 0; i < current_hash_table->capacity; i += 1) {
        FledastyError result = fledasty_dynamic_array_destroy(&current_hash_table->Table[i]);
        if (result != FLEDASTY_ERROR_NONE) {
            return result;
        }
    } 

    if (hallocy_free(current_hash_table->Table) != HALLOCY_ERROR_NONE) {
        return FLEDASTY_ERROR_FAILED_ALLOCATION;
    }

    return FLEDASTY_ERROR_NONE;
}

FledastyError fledasty_hash_table_insert(FledastyHashTable *current_hash_table, void *key, void *value) {
    if (current_hash_table == NULL || key == NULL || value == NULL) {
        return FLEDASTY_ERROR_INVALID_POINTER;
    }

    current_hash_table->size += 1;
    if (current_hash_table->size >= (current_hash_table->capacity * FLEDASTY_HASH_TABLE_SIZE_THRESHOLD) / 100) {
        const size_t old_capacity = current_hash_table->capacity;
        FledastyDynamicArray *previous_table = current_hash_table->Table;

        current_hash_table->capacity += current_hash_table->capacity;
        current_hash_table->Table = (FledastyDynamicArray*)hallocy_calloc(sizeof(FledastyDynamicArray), current_hash_table->capacity);
        if (current_hash_table->Table == NULL) {
            return FLEDASTY_ERROR_FAILED_ALLOCATION;
        }

        for (size_t index = 0; index < old_capacity; index += 1) {
            FledastyDynamicArray *current_dynamic_array = previous_table + index;
            if (current_dynamic_array->buffer != NULL) {
                for (size_t list_index = 0; list_index < current_dynamic_array->size; list_index += 1) {
                    FledastyHashTablePair *pair = (FledastyHashTablePair*)fledasty_dynamic_array_get(current_dynamic_array, list_index);

                    const size_t key_index = current_hash_table->hash_function(pair->key) % current_hash_table->capacity;
                    if (current_hash_table->Table[key_index].buffer == NULL) {
                        FledastyError result = fledasty_dynamic_array_initialize(current_hash_table->Table + key_index, NULL, 0, sizeof(FledastyHashTablePair));
                        if (result != FLEDASTY_ERROR_NONE) {
                            return result;
                        }            
                    }

                    fledasty_dynamic_array_append(current_hash_table->Table + key_index, pair);
                }

                fledasty_dynamic_array_destroy(current_dynamic_array);
            }
        }

        hallocy_free(previous_table);
    }

    const size_t index = current_hash_table->hash_function(key) % current_hash_table->capacity;
    if (current_hash_table->Table[index].buffer == NULL) {
        FledastyError result = fledasty_dynamic_array_initialize(&current_hash_table->Table[index], NULL, 0, sizeof(FledastyHashTablePair));
        if (result != FLEDASTY_ERROR_NONE) {
            return result;
        }
    }

    FledastyHashTablePair pair;

    pair.key = hallocy_malloc(current_hash_table->key_byte_size);
    if (pair.key == NULL) {
        return FLEDASTY_ERROR_FAILED_ALLOCATION;
    }

    hallocy_copy_memory(pair.key, key, current_hash_table->key_byte_size);

    pair.value = hallocy_malloc(current_hash_table->value_byte_size);
    if (pair.value == NULL) {
        return FLEDASTY_ERROR_FAILED_ALLOCATION;
    }

    hallocy_copy_memory(pair.value, value, current_hash_table->value_byte_size);

    fledasty_dynamic_array_append(&current_hash_table->Table[index], &pair);
    return FLEDASTY_ERROR_NONE;
}

void *fledasty_hash_table_get(const FledastyHashTable *current_hash_table, void *key) {
    if (current_hash_table == NULL || key == NULL) {
        return NULL;
    }

    const size_t index = current_hash_table->hash_function(key) % current_hash_table->capacity;
    if (current_hash_table->Table[index].buffer == NULL) {
        return NULL;
    }

    size_t list_index = 0;
    while (list_index < current_hash_table->Table[index].size) {
        const FledastyHashTablePair *value = (FledastyHashTablePair*)fledasty_dynamic_array_get(&current_hash_table->Table[index], list_index);
        if (hallocy_compare_memory(value->key, key, current_hash_table->key_byte_size)) {
            return value->value;
        }
        
        list_index += 1;
    }

    return NULL;    
}

FledastyError fledasty_hash_table_remove(FledastyHashTable *current_hash_table, void *key) {
    if (current_hash_table == NULL || key == NULL) {
        return FLEDASTY_ERROR_INVALID_POINTER;
    }

    const size_t index = current_hash_table->hash_function(key) % current_hash_table->capacity;
    if (current_hash_table->Table[index].buffer == NULL) {
        return FLEDASTY_ERROR_KEY_NOT_FOUND;
    }

    size_t list_index = 0;
    while (list_index < current_hash_table->Table[index].size) {
        FledastyHashTablePair *value = (FledastyHashTablePair*)fledasty_dynamic_array_get(&current_hash_table->Table[index], list_index);
        if (hallocy_compare_memory(value->key, key, current_hash_table->key_byte_size)) {
            if (hallocy_free(value->key) != HALLOCY_ERROR_NONE) {
                return FLEDASTY_ERROR_FAILED_ALLOCATION;
            }

            if (hallocy_free(value->value) != HALLOCY_ERROR_NONE) {
                return FLEDASTY_ERROR_FAILED_ALLOCATION;
            }

            fledasty_dynamic_array_remove_at_index(&current_hash_table->Table[index], list_index);
            current_hash_table->size -= 1;
            return FLEDASTY_ERROR_NONE;
        }

        list_index += 1;
    }

    return FLEDASTY_ERROR_KEY_NOT_FOUND;
}

FledastyError fledasty_hash_table_clear(FledastyHashTable *current_hash_table) {
    if (current_hash_table == NULL) {
        return FLEDASTY_ERROR_INVALID_POINTER;
    }

    for (size_t index = 0; index < current_hash_table->capacity; index += 1) {
        if (current_hash_table->Table[index].buffer != NULL) {
            FledastyError result = fledasty_dynamic_array_destroy(&current_hash_table->Table[index]);
            if (result != FLEDASTY_ERROR_NONE) {
                return result;
            }
        }
    }

    current_hash_table->size = 0;
    return FLEDASTY_ERROR_NONE;
}

bool fledasty_hash_table_has_key(const FledastyHashTable *current_hash_table, void *key) {
    if (current_hash_table == NULL || key == NULL) {
        return false;
    }

    const size_t index = current_hash_table->hash_function(key) % current_hash_table->capacity;
    if (current_hash_table->Table[index].buffer == NULL) {
        return false;
    }

    size_t list_index = 0;
    while (list_index < current_hash_table->Table[index].size) {
        const FledastyHashTablePair *value = (FledastyHashTablePair*)fledasty_dynamic_array_get(&current_hash_table->Table[index], list_index);
        if (hallocy_compare_memory(value->key, key, current_hash_table->key_byte_size)) {
            return true;
        }

        list_index += 1;
    }

    return false;
}