use ruff_diagnostics::Applicability;
use ruff_macros::{ViolationMetadata, derive_message_formats};
use ruff_python_ast::ExprCall;

use crate::checkers::ast::Checker;
use crate::preview::is_fix_os_path_expanduser_enabled;
use crate::rules::flake8_use_pathlib::helpers::check_os_pathlib_single_arg_calls;
use crate::{FixAvailability, Violation};

/// ## What it does
/// Checks for uses of `os.path.expanduser`.
///
/// ## Why is this bad?
/// `pathlib` offers a high-level API for path manipulation, as compared to
/// the lower-level API offered by `os.path`. When possible, using `Path` object
/// methods such as `Path.expanduser()` can improve readability over the `os.path`
/// module's counterparts (e.g., as `os.path.expanduser()`).
///
/// ## Examples
/// ```python
/// import os
///
/// os.path.expanduser("~/films/Monty Python")
/// ```
///
/// Use instead:
/// ```python
/// from pathlib import Path
///
/// Path("~/films/Monty Python").expanduser()
/// ```
///
/// ## Known issues
/// While using `pathlib` can improve the readability and type safety of your code,
/// it can be less performant than the lower-level alternatives that work directly with strings,
/// especially on older versions of Python.
///
/// ## Fix Safety
/// This rule's fix is always marked as unsafe because the behaviors of
/// `os.path.expanduser` and `Path.expanduser` differ when a user's home
/// directory can't be resolved: `os.path.expanduser` returns the
/// input unchanged, while `Path.expanduser` raises `RuntimeError`.
///
/// Additionally, the fix is marked as unsafe because `os.path.expanduser()` returns `str` or `bytes` (`AnyStr`),
/// while `Path.expanduser()` returns a `Path` object. This change in return type can break code that uses
/// the return value.
///
/// ## References
/// - [Python documentation: `Path.expanduser`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.expanduser)
/// - [Python documentation: `os.path.expanduser`](https://docs.python.org/3/library/os.path.html#os.path.expanduser)
/// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
/// - [Why you should be using pathlib](https://treyhunner.com/2018/12/why-you-should-be-using-pathlib/)
/// - [No really, pathlib is great](https://treyhunner.com/2019/01/no-really-pathlib-is-great/)
#[derive(ViolationMetadata)]
#[violation_metadata(stable_since = "v0.0.231")]
pub(crate) struct OsPathExpanduser;

impl Violation for OsPathExpanduser {
    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
    #[derive_message_formats]
    fn message(&self) -> String {
        "`os.path.expanduser()` should be replaced by `Path.expanduser()`".to_string()
    }
    fn fix_title(&self) -> Option<String> {
        Some("Replace with `Path(...).expanduser()`".to_string())
    }
}

/// PTH111
pub(crate) fn os_path_expanduser(checker: &Checker, call: &ExprCall, segments: &[&str]) {
    if segments != ["os", "path", "expanduser"] {
        return;
    }

    check_os_pathlib_single_arg_calls(
        checker,
        call,
        "expanduser()",
        "path",
        is_fix_os_path_expanduser_enabled(checker.settings()),
        OsPathExpanduser,
        Applicability::Unsafe,
    );
}
