"""
Урок 52. Основы работы с файлами — весь код примеров одним файлом.

Источник: subjects/python-fundamentals/course/lessons/52-file-basics/examples.html
Файл собран автоматически (tools/build_lesson_examples.py): правьте страницу урока.
Запуск: python lesson-52.py
"""



# ====================================================================
# Пример 1. Чтение всего файла методом read()
# ====================================================================
# example_01_read.py
with open("example.txt", "r", encoding="utf-8") as file:
    content = file.read()
    print(type(content))
    print(content)


# ====================================================================
# Пример 2. Чтение первых n символов
# ====================================================================
# example_02_read_n.py
with open("example.txt", "r", encoding="utf-8") as file:
    chunk = file.read(10)
    print(f"Первые 10 символов: {chunk!r}")


# ====================================================================
# Пример 3. Чтение построчно методом readline()
# ====================================================================
# example_03_readline.py
with open("example.txt", "r", encoding="utf-8") as file:
    first = file.readline()
    second = file.readline()
    print(f"1: {first!r}")
    print(f"2: {second!r}")


# ====================================================================
# Пример 4. Чтение всех строк в список
# ====================================================================
# example_04_readlines.py
with open("example.txt", "r", encoding="utf-8") as file:
    lines = file.readlines()
    print(type(lines))
    print(lines)


# ====================================================================
# Пример 5. Чтение файла в цикле
# ====================================================================
# example_05_loop.py
with open("example.txt", "r", encoding="utf-8") as file:
    for line in file:
        print(line, end="")


# ====================================================================
# Пример 6. Запись строки методом write()
# ====================================================================
# example_06_write.py
with open("users.txt", "w", encoding="utf-8") as file:
    file.write("ID: 201 | Name: John | Age: 25 | Status: Active\n")


# ====================================================================
# Пример 7. Запись списка строк методом writelines()
# ====================================================================
# example_07_writelines.py
data = [
    "ID: 202 | Name: Alice | Age: 30 | Status: Inactive\n",
    "ID: 203 | Name: Bob | Age: 27 | Status: Active\n",
]

with open("users.txt", "w", encoding="utf-8") as file:
    file.writelines(data)


# ====================================================================
# Пример 8. Добавление в конец файла
# ====================================================================
# example_08_append.py
with open("users.txt", "a", encoding="utf-8") as file:
    file.write("ID: 204 | Name: Charlie | Age: 22 | Status: Active\n")


# ====================================================================
# Пример 9. Режим r+ — чтение и запись
# ====================================================================
# example_09_rplus.py
with open("users.txt", "r+", encoding="utf-8") as file:
    content = file.read()
    print("Текущее содержимое:")
    print(content)
    file.write("ID: 205 | Name: Diana | Age: 29 | Status: Inactive\n")


# ====================================================================
# Пример 10. Режим x — безопасное создание файла
# ====================================================================
# example_10_x.py
try:
    with open("new_file.txt", "x", encoding="utf-8") as file:
        file.write("Created in mode 'x'.\n")
    print("Файл создан.")
except FileExistsError:
    print("Ошибка: файл уже существует.")


# ====================================================================
# Пример 11. Несколько файлов в одном with
# ====================================================================
# example_11_multiple.py
with (
    open("example.txt", "r", encoding="utf-8") as infile,
    open("output.txt", "w", encoding="utf-8") as outfile,
):
    for line in infile:
        outfile.write(line.upper())


# ====================================================================
# Пример 12. Обработка ошибок при открытии
# ====================================================================
# example_12_errors.py
filename = input("Введите имя файла: ")

try:
    with open(filename, "r", encoding="utf-8") as file:
        print(file.read())
except FileNotFoundError:
    print(f"Ошибка: файл '{filename}' не найден.")
except UnicodeDecodeError:
    print(f"Ошибка: не удалось прочитать файл '{filename}' с кодировкой utf-8.")