prdoclib 0.0.7

//! Definition of the standardized file names.

use regex::Regex;
use serde::Serialize;
use std::{
	ffi::OsString,
	fmt::Display,
	path::{Path, PathBuf},
	str::FromStr,
};

use crate::{
	common::PRNumber,
	error::{self, PRdocLibError},
	title::Title,
};

/// A `prdoc` is made of its content: a [DocFile](/prdoclib::docfile::DocFile) but also requires a
/// valid filename. This struct describe the filename pattern and provide helpers to build and check
/// valid `prdoc` filenames.
#[derive(Debug, PartialEq, Serialize, Hash, Eq)]
pub struct DocFileName {
	/// The PR number
	pub number: PRNumber,

	/// The title of the PR as mentioned in the filename. Note: This is NOT the title property of a
	/// PRDoc file.
	pub title: Option<Title>,
}

impl DocFileName {
	/// Construct a new `DocFileName` from a PR number and an optional title.
	pub fn new(number: PRNumber, title: Option<Title>) -> Self {
		Self { number, title }
	}

	/// Return the filename of the `prdoc` file.
	pub fn filename(&self) -> OsString {
		if let Some(title) = &self.title {
			OsString::from(format!("pr_{}_{:?}.prdoc", self.number, title.to_string()))
		} else {
			OsString::from(format!("pr_{}.prdoc", self.number))
		}
	}

	/// Return the regex used to parse filenames
	fn get_regex() -> Regex {
		Regex::new(r"^pr_(?<number>\d+)(?<title>.*)\.prdoc$").unwrap()
	}

	/// Return true if a filename **looks** like it could be a valid `prdoc` file.
	/// This is done solely based on the filename and the content it not attemptedly parsed or
	/// deserialized.
	pub fn is_valid<P: AsRef<Path>>(filename: P) -> bool {
		let re = Self::get_regex();
		let file_only = filename.as_ref().components().last();
		if let Some(file) = file_only {
			match file {
				std::path::Component::Prefix(_) |
				std::path::Component::RootDir |
				std::path::Component::CurDir |
				std::path::Component::ParentDir => false,

				std::path::Component::Normal(f) =>
					re.is_match(&PathBuf::from(f).display().to_string().to_lowercase()),
			}
		} else {
			false
		}
	}

	/// Search for a PR Doc in a given folder and matching the args
	pub fn find(
		number: PRNumber,
		title: Option<String>,
		directory: &PathBuf,
	) -> error::Result<PathBuf> {
		if title.is_some() {
			todo!("Searching by Number + Title is not implemented yet, open an issue if there is a need.");
		}

		// We search for matching patterns and capture the `number` group
		let re: Regex = Self::get_regex();

		let hit_maybe = std::fs::read_dir(directory)?.find_map(|entry| match entry {
			Ok(candidate) => {
				// First we exclude anything that is not a file
				let metadata = std::fs::metadata(candidate.path()).unwrap();
				if !metadata.is_file() {
					return None
				}

				// Fetch the file name
				let fname = candidate.file_name();
				let filename = fname.to_str().unwrap_or_default();

				// We capture numbers first
				let number_capture = re.captures(filename).and_then(|cap| {
					cap.name("number").map(|n| {
						let s = n.as_str();
						let my_num: PRNumber = s.parse().unwrap();
						my_num
					})
				});

				// Then check if the number we got matches.
				// It is required to do this so we also find `pr_000...` when looking for
				// PR #0
				if number_capture.is_some_and(|value| value == number) {
					Some(PathBuf::from(&directory).join(filename))
				} else {
					None
				}
			},
			Err(_e) => None,
		});

		if let Some(hit) = hit_maybe {
			Ok(hit)
		} else {
			Err(PRdocLibError::NumberNotFound(number))
		}
	}
}

impl Display for DocFileName {
	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
		f.write_str(self.filename().to_str().expect("Our filename is a valid path"))
	}
}

impl From<PRNumber> for DocFileName {
	fn from(n: PRNumber) -> Self {
		Self::new(n, None)
	}
}

impl From<DocFileName> for PathBuf {
	fn from(val: DocFileName) -> Self {
		PathBuf::from_str(&val.to_string()).expect("Our filename is a valid path")
	}
}

impl TryFrom<&PathBuf> for DocFileName {
	type Error = PRdocLibError;

	fn try_from(p: &PathBuf) -> Result<Self, Self::Error> {
		let re: Regex = Self::get_regex();

		let file = p.file_name().ok_or(PRdocLibError::InvalidFilename(p.clone()))?;
		let filename = file.to_str().ok_or(PRdocLibError::InvalidFilename(p.clone()))?;

		let number = re.captures(filename).and_then(|cap| {
			cap.name("number")
				.map(|n| n.as_str().parse().expect("The regexp captures numbers"))
		});

		let title: Option<Title> = re
			.captures(filename)
			.and_then(|cap| {
				cap.name("title").map(|s| {
					if s.is_empty() {
						None
					} else {
						Some(Title::from(s.as_str()))
					}
				})
			})
			.unwrap_or_default();

		if let Some(number) = number {
			Ok(DocFileName::new(number, title))
		} else {
			Err(PRdocLibError::InvalidFilename(filename.into()))
		}
	}
}

#[cfg(test)]
mod test_doc_file_name {
	use super::*;

	#[test]
	fn test_valid_names() {
		assert!(DocFileName::is_valid("pr_0.prdoc"));
		assert!(DocFileName::is_valid("pr_123.prdoc"));
		assert!(DocFileName::is_valid("pr_123_foo.prdoc"));
		assert!(DocFileName::is_valid("PR_123.prdoc"));

		assert!(!DocFileName::is_valid("PR_123.txt"));
		assert!(!DocFileName::is_valid("PR_ABC.txt"));
		assert!(!DocFileName::is_valid("1234.prdoc"));
	}

	#[test]
	fn test_mix() {
		assert_eq!(String::from("pr_123.prdoc"), DocFileName::from(123).to_string());
	}

	#[test]
	fn test_find() {
		assert_eq!(
			PathBuf::from("../tests/data/some/pr_1234_some_test_minimal.prdoc"),
			DocFileName::find(1234, None, &PathBuf::from("../tests/data/some")).unwrap()
		);
	}

	#[test]
	fn test_from_pathbuf() {
		let dfn = DocFileName::try_from(&PathBuf::from(
			"../tests/data/some/pr_1234_some_test_minimal.prdoc",
		))
		.unwrap();
		assert_eq!(1234, dfn.number);
		assert_eq!(Some(Title::from("_some_test_minimal")), dfn.title);
	}
}