/*
 * Copyright (c) 2025 Emma Tebibyte <emma@tebibyte.media>
 * SPDX-License-Identifier: AGPL-3.0-or-later
 *
 * This file is part of Mintee.
 *
 * Mintee is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Affero General Public License as published by the Free
 * Software Foundation, either version 3 of the License, or (at your option)
 * any later version.
 * 
 * Mintee is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
 * details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with Mintee. If not, see https://www.gnu.org/licenses/.
 *
 * This file incorporates work covered by the following copyright and
 * permission notice:
 *
 *     MIT License
 * 
 *     Copyright (c) 2021 Sergey "Shnatsel" Davidoff <shnatsel@gmail.com>
 * 
 *     Permission is hereby granted, free of charge, to any person obtaining a
 *     copy of this software and associated documentation files (the 
 *     "Software"), to deal in the Software without restriction, including 
 *     without limitation the rights to use, copy, modify, merge, publish,
 *     distribute, sublicense, and/or sell copies of the Software, and to
 *     permit persons to whom the Software is furnished to do so, subject to
 *     the following conditions:
 *
 *     The above copyright notice and this permission notice shall be included
 *     in all copies or substantial portions of the Software.
 * 
 *     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 *     OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 *     IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 *     CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 *     TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 
 *     SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

use std::{
	error::Error,
	path::PathBuf,
};

use git2::{ Branch, Commit, Repository, Sort, TreeEntry };

pub struct GitCommit {
	author: (Option<String>, Option<String>), // name, e-mail
	entries: Vec<GitEntry>,
	hash: String,
	message: Option<String>,
	short_hash: Option<String>,
	time: i64, // seconds since Unix epoch
}

impl TryFrom<Commit<'_>> for GitCommit {
	type Error = Box<dyn Error>;

	fn try_from(commit: Commit) -> Result<Self, Self::Error> {
		let hash = commit.id().to_string();
		let short_hash = commit.as_object().short_id()?.as_str().map(|f| f.to_owned());
		let message = commit.message().map(|f| f.to_owned());
		let commit_signature = commit.author();
		let name = commit_signature.name().map(|f| f.to_owned());
		let address = commit_signature.email().map(|f| f.to_owned());
		let author = (name, address);
		let time = commit.time().seconds();
		let entries = commit
			.tree()?
			.iter()
			.map(|c| -> Result<GitEntry, std::string::FromUtf8Error> {
				Ok(GitEntry::try_from(c)?)
			}).collect::<Result<Vec<_>, _>>()?;

		Ok(GitCommit { author, entries, hash, message, short_hash, time })
	}
}

pub struct GitEntry {
	path: String,
}

impl GitEntry {
	fn new(path: String) -> Self {
		GitEntry { path }
	}
}

impl TryFrom<TreeEntry<'_>> for GitEntry {
	type Error = std::string::FromUtf8Error;

	fn try_from(entry: TreeEntry) -> Result<Self, Self::Error> {
		let path = String::from_utf8(entry.name_bytes().to_vec())?;
		Ok(Self { path })
	}
}

pub struct GitBranch {
	commits: Vec<GitCommit>,
	name: String,
}

struct GitBranchWrapper<'a> {
	branch: Branch<'a>,
	repo: &'a Repository,
}

impl<'a> GitBranchWrapper<'a> {
	fn new(branch: Branch<'a>, repo: &'a Repository) -> Self {
		Self { branch, repo }
	}
}

impl TryFrom<GitBranchWrapper<'_>> for GitBranch {
	type Error = Box<dyn Error>;

	fn try_from(branch: GitBranchWrapper) -> Result<Self, Self::Error> {
		let name = String::from_utf8(branch.branch.name_bytes()?.to_vec())?;
		let repo = branch.repo;
		let branch_oid = branch.branch.get().target().unwrap();

		let mut revwalk = repo.revwalk()?;
		revwalk.set_sorting(Sort::TOPOLOGICAL | Sort::TIME)?;
		revwalk.push(branch_oid)?;

		let commits = revwalk
			.into_iter()
			.map(|o| -> Result<GitCommit, Box<dyn Error>> {
				Ok(GitCommit::try_from(repo.find_commit(o?)?)?)
			}).collect::<Result<Vec<_>, _>>()?;

		Ok(GitBranch { commits, name })
	}

}

pub struct GitRepo {
	branches: Vec<GitBranch>,
	name: String,
	owner: String,
}

impl GitRepo {
	fn open(path: PathBuf) -> Result<Self, Box<dyn Error>> {
		let repo = Repository::open(path.clone())?;

		let branches = repo
			.branches(None)?
			.map(|b| -> Result<GitBranch, Box<dyn Error>> {
				Ok(GitBranch::try_from(GitBranchWrapper::new(b?.0, &repo))?)
			}).collect::<Result<Vec<_>, _>>()?;
		/*
		let mut revwalk = repo.revwalk()?;
		
		revwalk.set_sorting(Sort::TOPOLOGICAL | Sort::TIME)?;
		revwalk.push_head()?;
		let commits = revwalk
			.into_iter()
			.map(|o| -> Result<GitCommit, Box<dyn Error>> {
				Ok(GitCommit::try_from(repo.find_commit(o?)?)?)
			}).collect::<Result<Vec<_>, _>>()?;
		*/

		let full_path = path.clone().as_path().canonicalize()?;

		let relative_path = full_path.strip_prefix("/var/mintee/repos")?;

		let owner = String::from_utf8(
			relative_path
			.parent()
			.unwrap()
			.to_path_buf()
			.as_mut_os_string()
			.as_encoded_bytes()
			.to_vec()
		)?;

		let name = String::from_utf8(
			relative_path
			.file_name()
			.unwrap()
			.to_owned()
			.as_encoded_bytes()
			.to_vec()
		)?;

		Ok(GitRepo { branches, name, owner })
	}

	fn get_remote_repo() { // for AP repos
		todo!();
	}
}