use anyhow::Context;
use std::{fs, path::Path};

pub fn find_unique_file(dir_path: &str, suffix: &str) -> anyhow::Result<String> {
    let mut matching_files = Vec::new();

    for entry in
        fs::read_dir(dir_path).with_context(|| format!("Failed to read directory: {}", dir_path))?
    {
        let entry = entry.with_context(|| "Failed to read directory entry")?;
        let path = entry.path();

        if path.is_file()
            && path
                .file_name()
                .and_then(|name| name.to_str())
                .map(|name| name.ends_with(suffix))
                .unwrap_or(false)
        {
            matching_files.push(path);
        }
    }

    match matching_files.len() {
        0 => Err(anyhow::anyhow!("No file found ending with '{}'", suffix))
            .with_context(|| format!("In directory: {}", dir_path)),
        1 => Ok(matching_files[0].to_string_lossy().into_owned()),
        _ => Err(anyhow::anyhow!(
            "Multiple files found ending with '{}'",
            suffix
        ))
        .with_context(|| format!("In directory: {}", dir_path)),
    }
}

pub fn path_prefix(out: &str) -> anyhow::Result<String> {
    let out_path = Path::new(&out);

    let out_dir = out_path
        .parent()
        .ok_or_else(|| anyhow::anyhow!("Can't parse the dir of {}", out_path.display()))?;

    let name = out_path
        .file_name()
        .and_then(|name| name.to_str())
        .ok_or_else(|| anyhow::anyhow!("Can't parse the file name of {}", out_path.display()))?;

    let stem = name
        .split_once('.')
        .map(|(stem, _)| stem)
        .ok_or_else(|| anyhow::anyhow!("Can't parse the file stem of {}", name))?;

    Ok(format!("{}/{stem}", out_dir.display()))
}

pub fn force_or_not(path: &str, force: bool) -> anyhow::Result<()> {
    let path = Path::new(path);
    let mut output_exists = path.exists();

    if force && output_exists {
        fs::remove_dir_all(
            path.parent()
                .context(format!("Can't parse the parent dir of {}", path.display()))?,
        )?;
        output_exists = false;
    }

    if output_exists {
        anyhow::bail!("{} already exists.", path.display())
    }
    Ok(())
}