mod archive;
mod blame;
mod branch;
mod cache;
mod commit;
mod diff;
mod merge;
mod pack;
mod repository;
mod repository_maint;
mod tag;
mod tree;

use std::path::PathBuf;
use tokio_stream::wrappers::ReceiverStream;

use crate::bare::GitBare;
use crate::error::GitError;
use crate::pb::{
    archive_service_server, blame_service_server, branch_service_server, commit_service_server,
    diff_service_server, merge_service_server, pack_service_server, repository_service_server,
    tag_service_server, tree_service_server,
};

#[derive(Clone)]
pub struct GitksService {
    /// Root prefix path for all repositories
    pub repo_prefix: PathBuf,
}

impl GitksService {
    fn repo_label(&self, header: Option<&crate::pb::RepositoryHeader>) -> String {
        header
            .and_then(|h| {
                if h.relative_path.is_empty() {
                    None
                } else {
                    Some(h.relative_path.clone())
                }
            })
            .unwrap_or_else(|| "unknown".into())
    }

    pub(crate) fn resolve(
        &self,
        header: Option<&crate::pb::RepositoryHeader>,
    ) -> Result<GitBare, tonic::Status> {
        let header =
            header.ok_or_else(|| tonic::Status::invalid_argument("repository is required"))?;
        let header = self.prefixed_header(header);
        let gb = GitBare::from_repository_header(&header).map_err(into_status)?;
        tracing::debug!(
            repo = %gb.bare_dir.display(),
            "resolved repository"
        );
        Ok(gb)
    }

    pub(crate) fn resolve_for_init(
        &self,
        header: Option<&crate::pb::RepositoryHeader>,
    ) -> Result<PathBuf, tonic::Status> {
        let header =
            header.ok_or_else(|| tonic::Status::invalid_argument("repository is required"))?;
        let relative_path = header.relative_path.trim();
        if relative_path.is_empty() {
            return Err(tonic::Status::invalid_argument("relative_path is required"));
        }
        let candidate = self.repo_prefix.join(relative_path);
        // Path traversal check
        let canonical = candidate
            .canonicalize()
            .unwrap_or_else(|_| candidate.clone());
        let prefix_canon = self
            .repo_prefix
            .canonicalize()
            .unwrap_or_else(|_| self.repo_prefix.clone());
        if !canonical.starts_with(&prefix_canon) {
            return Err(tonic::Status::invalid_argument(
                "path traversal detected: relative_path escapes repo prefix",
            ));
        }
        Ok(canonical)
    }

    /// Inject repo_prefix as storage_path into the client-provided header
    fn prefixed_header(&self, header: &crate::pb::RepositoryHeader) -> crate::pb::RepositoryHeader {
        crate::pb::RepositoryHeader {
            storage_path: self.repo_prefix.to_string_lossy().into_owned(),
            relative_path: header.relative_path.clone(),
            storage_name: header.storage_name.clone(),
        }
    }
}

pub(crate) fn into_status(e: GitError) -> tonic::Status {
    match &e {
        GitError::NotFound(_)
        | GitError::ObjectNotFound(_)
        | GitError::RefNotFound(_)
        | GitError::RepoNotFound => tonic::Status::not_found(e.to_string()),
        GitError::InvalidArgument(_) => tonic::Status::invalid_argument(e.to_string()),
        GitError::PermissionDenied(_) => tonic::Status::permission_denied(e.to_string()),
        GitError::Locked(_) => tonic::Status::failed_precondition(e.to_string()),
        GitError::AuthFailed(_) => tonic::Status::unauthenticated(e.to_string()),
        GitError::NotBareRepository => tonic::Status::failed_precondition(e.to_string()),
        _ => tonic::Status::internal(e.to_string()),
    }
}

impl From<GitError> for tonic::Status {
    fn from(e: GitError) -> Self {
        into_status(e)
    }
}

pub(crate) fn into_stream<T: Send + 'static>(
    items: Vec<T>,
) -> ReceiverStream<Result<T, tonic::Status>> {
    let (tx, rx) = tokio::sync::mpsc::channel(items.len().max(1));
    for item in items {
        let _ = tx.try_send(Ok(item));
    }
    ReceiverStream::new(rx)
}

pub(crate) fn git_cmd(gb: &GitBare, args: &[&str]) -> Result<std::process::Output, tonic::Status> {
    let mut full_args: Vec<String> = vec![
        "--git-dir".into(),
        gb.bare_dir.to_string_lossy().into_owned(),
    ];
    full_args.extend(args.iter().map(|s| s.to_string()));
    tracing::debug!(
        repo = %gb.bare_dir.display(),
        args = %full_args.iter().skip(2).cloned().collect::<Vec<_>>().join(" "),
        "spawning git subprocess"
    );
    let result = std::process::Command::new("git")
        .args(&full_args)
        .output()
        .map_err(|e| {
            tracing::error!(
                repo = %gb.bare_dir.display(),
                error = %e,
                "failed to spawn git subprocess"
            );
            tonic::Status::internal(e.to_string())
        })?;
    if !result.status.success() {
        let stderr = String::from_utf8_lossy(&result.stderr);
        tracing::warn!(
            repo = %gb.bare_dir.display(),
            status = ?result.status.code(),
            stderr = %stderr.trim(),
            "git subprocess exited with non-zero status"
        );
    }
    Ok(result)
}

pub async fn serve(
    addr: std::net::SocketAddr,
    repo_prefix: PathBuf,
) -> Result<(), tonic::transport::Error> {
    let span = tracing::info_span!("gitks.server", %addr);
    let _enter = span.enter();
    let svc = GitksService { repo_prefix };
    tracing::info!("registering gRPC services");
    let server = tonic::transport::Server::builder()
        .add_service(repository_service_server::RepositoryServiceServer::new(
            svc.clone(),
        ))
        .add_service(archive_service_server::ArchiveServiceServer::new(
            svc.clone(),
        ))
        .add_service(blame_service_server::BlameServiceServer::new(svc.clone()))
        .add_service(branch_service_server::BranchServiceServer::new(svc.clone()))
        .add_service(commit_service_server::CommitServiceServer::new(svc.clone()))
        .add_service(diff_service_server::DiffServiceServer::new(svc.clone()))
        .add_service(merge_service_server::MergeServiceServer::new(svc.clone()))
        .add_service(pack_service_server::PackServiceServer::new(svc.clone()))
        .add_service(tag_service_server::TagServiceServer::new(svc.clone()))
        .add_service(tree_service_server::TreeServiceServer::new(svc));
    tracing::info!("server ready, starting to accept connections");
    server.serve(addr).await
}