use std::{fs::File, path::Path};

use crate::Timestamp;

/// Returns the last modified time for the given file path as a Jiff timestamp.

///

/// If there was a problem accessing the last modified time or if it could not

/// fit in a Jiff timestamp, then a warning message is logged and `None` is

/// returned.

pub(crate) fn last_modified_from_path(path: &Path) -> Option<Timestamp> {

    let file = match File::open(path) {

        Ok(file) => file,

        Err(_err) => {

            warn!(

                "failed to open file to get last modified time {}: {_err}",

                path.display(),

            );

            return None;

        }

    };

    last_modified_from_file(path, &file)

}

/// Returns the last modified time for the given file as a Jiff timestamp.

///

/// If there was a problem accessing the last modified time or if it could not

/// fit in a Jiff timestamp, then a warning message is logged and `None` is

/// returned.

///

/// The path given should be the path to the given file. It is used for

/// diagnostic purposes.

pub(crate) fn last_modified_from_file(

    _path: &Path,

    file: &File,

) -> Option<Timestamp> {

    let md = match file.metadata() {

        Ok(md) => md,

        Err(_err) => {

            warn!(

                "failed to get metadata (for last modified time) \

                 for {}: {_err}",

                _path.display(),

            );

            return None;

        }

    };

    let systime = match md.modified() {

        Ok(systime) => systime,

        Err(_err) => {

            warn!(

                "failed to get last modified time for {}: {_err}",

                _path.display()

            );

            return None;

        }

    };

    let timestamp = match Timestamp::try_from(systime) {

        Ok(timestamp) => timestamp,

        Err(_err) => {

            warn!(

                "system time {systime:?} out of bounds \

                 for Jiff timestamp for last modified time \

                 from {}: {_err}",

                _path.display(),

            );

            return None;

        }

    };

    Some(timestamp)

}