/*
 * 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: UTF8String.c
 * Description:
 *  This file contains the functions for modifying the UTF-8 String. It includes 
 *  functions to append, Insert at index, insert before character,
 *  insert before string, insert after character, insert after string, replace,
 *  copy, pop, remove, remove range, clear, check if contains string, check if
 *  empty. 
 * 
 * Author: Mineplay
 * -----------------------------------------------------------------------------
 */
#include "../../Include/Fledasty/Strings/UTF8String.h"

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

static const size_t FLEDASTY_STRING_DEFAULT_ALLOCATION_SIZE = 16;

FledastyError fledasty_utf8_string_free(FledastyUtf8String *current_string) {
    if (current_string == NULL) {
        return FLEDASTY_ERROR_INVALID_POINTER;
    }
    
    if (hallocy_free(current_string->character_string) != HALLOCY_ERROR_NONE) {
        return FLEDASTY_ERROR_FAILED_ALLOCATION;
    }

    current_string->character_string = NULL;
    return FLEDASTY_ERROR_NONE;
}

FledastyError fledasty_utf8_string_append(FledastyUtf8String *current_string, unsigned char *character_string, const size_t character_string_size) {
    if (current_string == NULL || character_string == NULL || character_string_size == 0) {
        return FLEDASTY_ERROR_INVALID_POINTER;
    }

    if (!fledasty_utf8_string_validate(character_string, character_string_size)) {
        return FLEDASTY_ERROR_INVALID_VALUE;
    }

    if (current_string->capacity <= current_string->size + character_string_size) {
        current_string->capacity += (current_string->capacity > character_string_size) ? current_string->capacity : character_string_size + 1;
        current_string->character_string = (unsigned char*)hallocy_realloc(current_string->character_string, current_string->capacity * sizeof(unsigned char));

        if (current_string->character_string == NULL) {
            return FLEDASTY_ERROR_FAILED_ALLOCATION;
        }
    }

    hallocy_copy_memory(current_string->character_string + current_string->size, character_string, character_string_size);

    current_string->size += character_string_size;
    current_string->character_string[current_string->size] = '\0';

    return FLEDASTY_ERROR_NONE;
}

FledastyError fledasty_utf8_string_insert_at_index(FledastyUtf8String *current_string, const size_t index, unsigned char *character_string, const size_t character_string_size) {
    if (current_string == NULL || character_string == NULL || character_string_size == 0) {
        return FLEDASTY_ERROR_INVALID_POINTER;
    }

    if (index > current_string->size) {
        return FLEDASTY_ERROR_INDEX_OUT_OF_RANGE;
    }

    if (!fledasty_utf8_string_validate(character_string, character_string_size)) {
        return  FLEDASTY_ERROR_INVALID_VALUE;
    }

    if (current_string->capacity <= current_string->size + character_string_size) {
        current_string->capacity += (current_string->capacity > character_string_size) ? current_string->capacity : character_string_size;
        current_string->character_string = (unsigned char*)hallocy_realloc(current_string->character_string, current_string->capacity * sizeof(unsigned char));

        if (current_string->character_string == NULL) {
            return FLEDASTY_ERROR_FAILED_ALLOCATION;
        }
    }

    hallocy_move_memory(current_string->character_string + (index + character_string_size), current_string->character_string + index, current_string->size - index);
    hallocy_copy_memory(current_string->character_string + index, character_string, character_string_size);
    
    current_string->size += character_string_size;
    current_string->character_string[current_string->size] = '\0';
    return FLEDASTY_ERROR_NONE;
}

FledastyError fledasty_utf8_string_insert_before_string(FledastyUtf8String *current_string, unsigned char *before_character_string, const size_t before_character_string_size, unsigned char *character_string, const size_t character_string_size) {
    if (current_string == NULL || before_character_string == NULL  || before_character_string_size == 0 || character_string == NULL || character_string_size == 0) {
        return FLEDASTY_ERROR_INVALID_POINTER;
    }

    if (!fledasty_utf8_string_validate(before_character_string, before_character_string_size) || !fledasty_utf8_string_validate(character_string, character_string_size)) {
        return FLEDASTY_ERROR_INVALID_VALUE;
    }

    size_t index = 0;
    while (index < (current_string->size - before_character_string_size)) {
        if (hallocy_compare_memory(current_string->character_string + index, before_character_string, before_character_string_size)) {
            if (current_string->capacity <= current_string->size + character_string_size) {
                current_string->capacity += (current_string->capacity > character_string_size) ? current_string->capacity : character_string_size + 1;
                current_string->character_string = (unsigned char*)hallocy_realloc(current_string->character_string, current_string->capacity * sizeof(unsigned char));

                if (current_string->character_string == NULL) {
                    return FLEDASTY_ERROR_FAILED_ALLOCATION;
                }
            }
        
            hallocy_move_memory(current_string->character_string + (index + character_string_size), current_string->character_string + index, current_string->size - index);
            hallocy_copy_memory(current_string->character_string + index, character_string, character_string_size);
            
            current_string->size += character_string_size;
            current_string->character_string[current_string->size] = '\0';

            return FLEDASTY_ERROR_NONE;
        }

        index += 1;
    }

    return FLEDASTY_ERROR_VALUE_NOT_FOUND;   
}

FledastyError fledasty_utf8_string_insert_after_string(FledastyUtf8String *current_string, unsigned char *after_character_string, const size_t after_character_string_size, unsigned char *character_string, const size_t character_string_size) {
    if (current_string == NULL || after_character_string == NULL || after_character_string_size == 0 || character_string == NULL || character_string_size == 0) {
        return FLEDASTY_ERROR_INVALID_POINTER;
    }

    if (!fledasty_utf8_string_validate(after_character_string, after_character_string_size) || !fledasty_utf8_string_validate(character_string, character_string_size)) {
        return FLEDASTY_ERROR_INVALID_VALUE;
    }

    size_t index = 0;
    while (index < (current_string->size - after_character_string_size)) {
        if (hallocy_compare_memory(current_string->character_string + index, after_character_string, after_character_string_size)) {
            if (current_string->capacity <= current_string->size + character_string_size) {
                current_string->capacity += (current_string->capacity > character_string_size) ? current_string->capacity : character_string_size + 1;
                current_string->character_string = (unsigned char*)hallocy_realloc(current_string->character_string, current_string->capacity * sizeof(unsigned char));

                if (current_string->character_string == NULL) {
                    return FLEDASTY_ERROR_FAILED_ALLOCATION;
                }
            }
        
            index += after_character_string_size;
            hallocy_move_memory(current_string->character_string + (index + character_string_size), current_string->character_string + index, current_string->size - index + 1);
            hallocy_copy_memory(current_string->character_string + index, character_string, character_string_size);
            
            current_string->size += character_string_size;
            current_string->character_string[current_string->size] = '\0';

            return FLEDASTY_ERROR_NONE;
        }

        index += 1;
    }

    return FLEDASTY_ERROR_VALUE_NOT_FOUND;
}

FledastyError fledasty_utf8_string_pop(FledastyUtf8String *current_string) {
    if (current_string == NULL) {
        return FLEDASTY_ERROR_INVALID_POINTER;
    }

    if ((current_string->character_string[current_string->size - 5] & 0xF0) == 0xF0) {
        current_string->size -= 4;
    } else if ((current_string->character_string[current_string->size - 4] & 0xE0) == 0xC0) {
        current_string->size -= 3;        
    } else if ((current_string->character_string[current_string->size - 3] & 0xC0) == 0xC0) {
        current_string->size -= 2;
    } else {
        current_string->size -= 1;
    }

    current_string->character_string[current_string->size] = '\0';

    return FLEDASTY_ERROR_NONE;
}

FledastyError fledasty_utf8_string_remove(FledastyUtf8String *current_string, unsigned char *character_string, const size_t character_string_size) {
    if (current_string == NULL || character_string == NULL || character_string_size == 0) {
        return FLEDASTY_ERROR_INVALID_POINTER;
    }

    if (!fledasty_utf8_string_validate(character_string, character_string_size)) {
        return FLEDASTY_ERROR_INVALID_VALUE;
    }

    size_t index = 0;
    while (index < (current_string->size - character_string_size)) {
        if (hallocy_compare_memory(current_string->character_string + index, character_string, character_string_size)) {
            hallocy_move_memory(current_string->character_string + index, current_string->character_string + index + character_string_size, current_string->size - (index + character_string_size));
        
            current_string->size -= character_string_size;
            current_string->character_string[current_string->size] = '\0';
            
            return FLEDASTY_ERROR_NONE;
        }

        index += 1;
    }

    return FLEDASTY_ERROR_VALUE_NOT_FOUND;
}

FledastyError fledasty_utf8_string_remove_range(FledastyUtf8String *current_string, const size_t start_index, const size_t end_index) {
    if (current_string == NULL) {
        return FLEDASTY_ERROR_INVALID_POINTER;
    }

    if (start_index >= end_index || end_index >= current_string->size) {
        return FLEDASTY_ERROR_INDEX_OUT_OF_RANGE;
    }

    hallocy_move_memory(current_string->character_string + start_index, current_string->character_string + end_index, current_string->size - end_index);

    current_string->size -= end_index - start_index;
    current_string->character_string[current_string->size] = '\0';
    return FLEDASTY_ERROR_NONE;
}

FledastyError fledasty_utf8_string_replace_string(FledastyUtf8String *current_string, unsigned char *replace_character_string, const size_t replace_character_string_size, unsigned char *character_string, const size_t character_string_size) {
    if (current_string == NULL || replace_character_string == NULL || replace_character_string_size == 0 || character_string == NULL || character_string_size == 0) {
        return FLEDASTY_ERROR_INVALID_POINTER;
    }

    if (!fledasty_utf8_string_validate(replace_character_string, replace_character_string_size) || !fledasty_utf8_string_validate(character_string, character_string_size)) {
        return FLEDASTY_ERROR_INVALID_VALUE;
    }

    size_t index = 0;
    while (index < current_string->size - replace_character_string_size) {
        if (hallocy_compare_memory(current_string->character_string + index, replace_character_string, replace_character_string_size)) {
            const size_t new_size = current_string->size + (character_string_size - replace_character_string_size);
            if (current_string->capacity <= new_size) {
                current_string->capacity += (current_string->capacity > character_string_size) ? current_string->capacity : character_string_size;
                current_string->character_string = (unsigned char*)hallocy_realloc(current_string->character_string, current_string->capacity * sizeof(unsigned char));

                if (current_string->character_string == NULL) {
                    return FLEDASTY_ERROR_FAILED_ALLOCATION;
                }
            }

            hallocy_move_memory(current_string->character_string + index + character_string_size, current_string->character_string + index + replace_character_string_size, current_string->size - (index + replace_character_string_size));
            hallocy_copy_memory(current_string->character_string + index, character_string, character_string_size);

            current_string->size = new_size;
            current_string->character_string[current_string->size] = '\0';
            return FLEDASTY_ERROR_NONE;
        }
        index += 1;
    }

    return FLEDASTY_ERROR_VALUE_NOT_FOUND;
}

FledastyError fledasty_utf8_string_clear(FledastyUtf8String *current_string) {
    if (current_string == NULL) {
        return FLEDASTY_ERROR_INVALID_POINTER;
    }

    current_string->size = 0;
    current_string->character_string[0] = '\0';

    return FLEDASTY_ERROR_NONE;
}

FledastyError fledasty_utf8_string_shrink_to_fit(FledastyUtf8String *current_string) {
    if (current_string == NULL) {
        return FLEDASTY_ERROR_INVALID_POINTER;
    }

    unsigned char *previous_string = current_string->character_string;

    current_string->capacity = current_string->size + 1;
    current_string->character_string = (unsigned char*)hallocy_malloc(current_string->capacity);
    if (current_string->character_string == NULL) {
        return FLEDASTY_ERROR_FAILED_ALLOCATION;
    }

    hallocy_copy_memory(current_string->character_string, previous_string, current_string->size);
    current_string->character_string[current_string->size] = '\0';

    hallocy_free(previous_string);
    return FLEDASTY_ERROR_NONE;
}

bool fledasty_utf8_string_has_string(const FledastyUtf8String *current_string, unsigned char *character_string, const size_t character_string_size) {
    if (current_string == NULL || character_string == NULL || character_string_size == 0) {
        return false;
    }

    if (!fledasty_utf8_string_validate(character_string, character_string_size)) {
        return false;
    }

    size_t index = 0;
    while (index < current_string->size - character_string_size) {
        if (hallocy_compare_memory(current_string->character_string + index, character_string, character_string_size)) {
            return true;
        }

        index += 1;
    }

    return false;
}

FledastyUtf8String fledasty_utf8_string_encode(const uint32_t *unicode, const size_t size) {
    FledastyUtf8String utf8_string = { 0, 0, NULL };
    if (unicode == NULL) {
        return utf8_string;
    }

    size_t string_index = 0;
    for (size_t index = 0; index < size; index += 1) {
        if (unicode[index] <= 0x00007F) {
            if (utf8_string.capacity <= string_index) {
                utf8_string.capacity += (utf8_string.capacity > FLEDASTY_STRING_DEFAULT_ALLOCATION_SIZE) ? utf8_string.capacity : FLEDASTY_STRING_DEFAULT_ALLOCATION_SIZE;
                utf8_string.character_string = (unsigned char*)hallocy_realloc(utf8_string.character_string, utf8_string.capacity);

                if (utf8_string.character_string == NULL) {
                    return utf8_string;
                }
            }

            utf8_string.character_string[string_index] = unicode[index];
            string_index += 1;
        } else if (unicode[index] <= 0x0007FF) {          
            if (utf8_string.capacity <= string_index + 2) {
                utf8_string.capacity += (utf8_string.capacity > FLEDASTY_STRING_DEFAULT_ALLOCATION_SIZE) ? utf8_string.capacity : FLEDASTY_STRING_DEFAULT_ALLOCATION_SIZE;
                utf8_string.character_string = (unsigned char*)hallocy_realloc(utf8_string.character_string, utf8_string.capacity);
                
                if (utf8_string.character_string == NULL) {
                    return utf8_string;
                }
            }

            utf8_string.character_string[string_index] = 0xC0 | ((unicode[index] >> 6) & 0x07);
            utf8_string.character_string[string_index + 1] = 0x80 | (unicode[index] & 0x3F);
            string_index += 2;
        } else if (unicode[index] <= 0x00FFFF) {
            if (utf8_string.capacity <= string_index + 3) {
                utf8_string.capacity += (utf8_string.capacity > FLEDASTY_STRING_DEFAULT_ALLOCATION_SIZE) ? utf8_string.capacity : FLEDASTY_STRING_DEFAULT_ALLOCATION_SIZE;
                utf8_string.character_string = (unsigned char*)hallocy_realloc(utf8_string.character_string, utf8_string.capacity);
                
                if (utf8_string.character_string == NULL) {
                    return utf8_string;
                }
            }

            utf8_string.character_string[string_index] = 0xE0 | ((unicode[index] >> 12) & 0x07);
            utf8_string.character_string[string_index + 1] = 0x80 | ((unicode[index] >> 6) & 0x3F);
            utf8_string.character_string[string_index + 2] = 0x80 | (unicode[index] & 0x3F);
            string_index += 3;
        } else if (unicode[index] <= 0x10FFFF) {
            if (utf8_string.capacity <= string_index + 4) {
                utf8_string.capacity += (utf8_string.capacity > FLEDASTY_STRING_DEFAULT_ALLOCATION_SIZE) ? utf8_string.capacity : FLEDASTY_STRING_DEFAULT_ALLOCATION_SIZE;
                utf8_string.character_string = (unsigned char*)hallocy_realloc(utf8_string.character_string, utf8_string.capacity);

                if (utf8_string.character_string == NULL) {
                    return utf8_string;
                }
            }

            utf8_string.character_string[string_index] = 0xF0 | ((unicode[index] >> 18) & 0x07);
            utf8_string.character_string[string_index + 1] = 0x80 | ((unicode[index] >> 12) & 0x3F);
            utf8_string.character_string[string_index + 2] = 0x80 | ((unicode[index] >> 6) & 0x3F);
            utf8_string.character_string[string_index + 3] = 0x80 | (unicode[index] & 0x3F);
            string_index += 4;
        }
    }

    utf8_string.size = string_index;
    if (utf8_string.capacity <= utf8_string.size) {
        utf8_string.capacity += (utf8_string.capacity > FLEDASTY_STRING_DEFAULT_ALLOCATION_SIZE) ? utf8_string.capacity : FLEDASTY_STRING_DEFAULT_ALLOCATION_SIZE;
        utf8_string.character_string = (unsigned char*)hallocy_realloc(utf8_string.character_string, utf8_string.capacity);
    }

    utf8_string.character_string[utf8_string.size] = '\0';
    return utf8_string;
}

uint32_t *fledasty_utf8_string_decode(const FledastyUtf8String *current_string, size_t *unicode_string_size) {
    if (current_string == NULL || unicode_string_size == NULL) {
        return NULL;
    }

    (*unicode_string_size) = 0;
    size_t index = 0;
    uint32_t *unicode_string = (uint32_t*)hallocy_malloc(current_string->size * sizeof(uint32_t));
    if (unicode_string == NULL) {
        return NULL;
    }

    while (index < current_string->size) {
        if ((current_string->character_string[index] & 0xF0) == 0xF0) {
            unicode_string[*unicode_string_size] = ((current_string->character_string[index] & 0x07) << 18) | ((current_string->character_string[index + 1] & 0x3F) << 12) | ((current_string->character_string[index + 2] & 0x3F) << 6) | (current_string->character_string[index + 3] & 0x3F);
            index += 4;
        } else if ((current_string->character_string[index] & 0xE0) == 0xE0) {
            unicode_string[*unicode_string_size] = ((current_string->character_string[index] & 0x0F) << 12) | ((current_string->character_string[index + 1] & 0x3F) << 6) | (current_string->character_string[index + 2] & 0x3F);
            index += 3;
        } else if ((current_string->character_string[index] & 0xC0) == 0xC0) {
            unicode_string[*unicode_string_size] = ((current_string->character_string[index] & 0x1F) << 6) | (current_string->character_string[index + 1] & 0x3F);
            index += 2;
        } else {
            unicode_string[*unicode_string_size] = current_string->character_string[index];
            index += 1;
        }

        (*unicode_string_size) += 1;
    }

    return unicode_string;
}

bool fledasty_utf8_string_validate(unsigned char *character_string, const size_t character_string_size) {
    if (character_string == NULL) {
        return false;
    }

    size_t index = 0;
    while (index < character_string_size) {
        if ((character_string[index] & 0xF0) == 0xF0) {
            if (index + 3 >= character_string_size) {
                return false;
            }

            if ((character_string[index + 1] & 0xC0) != 0x80) {
                return false;
            } else if ((character_string[index + 2] & 0xC0) != 0x80) {
                return false;
            } else if ((character_string[index + 3] & 0xC0) != 0x80) {
                return false;
            }
            
            index += 4;
        } else if ((character_string[index] & 0xE0) == 0xC0) {
            if (index + 2 >= character_string_size) {
                return false;
            }

            if ((character_string[index + 1] & 0xC0) != 0x80) {
                return false;
            } else if ((character_string[index + 2] & 0xC0) != 0x80) {
                return false;
            }

            index += 3;
        } else if ((character_string[index] & 0xC0) == 0xC0) {
            if (index + 1 >= character_string_size) {
                return false;
            }

            if ((character_string[index + 1] & 0xC0) != 0x80) {
                return false;
            }

            index += 2;
        } else {
            index += 1;
        }
    }

    return true;
}

size_t fledasty_utf8_string_get_size(const unsigned char *character_string) {
    size_t size = 0;
    while (character_string[size] != '\0') {
        size += 1;
    }

    return size;
}