use gix::object::tree::EntryKind;

use crate::bare::GitBare;
use crate::error::{GitError, GitResult};
use crate::paginate;
use crate::pb::{ListTreeRequest, ListTreeResponse, TreeEntry, object_selector, tree_entry};

impl GitBare {
    pub fn list_tree(&self, request: ListTreeRequest) -> GitResult<ListTreeResponse> {
        let repo = self.gix_repo()?;
        let revision = match request.revision.clone().and_then(|s| s.selector) {
            Some(object_selector::Selector::Oid(oid)) => oid.hex,
            Some(object_selector::Selector::Revision(name)) => name.revision,
            None => "HEAD".into(),
        };
        let mut tree = repo
            .rev_parse_single(format!("{}^{{tree}}", revision).as_str())?
            .object()?
            .try_into_tree()
            .map_err(|e| GitError::Gix(e.to_string()))?;
        if !request.path.is_empty() {
            let entry = tree
                .lookup_entry_by_path(&request.path)?
                .ok_or_else(|| GitError::NotFound(request.path.clone()))?;
            tree = entry
                .object()?
                .try_into_tree()
                .map_err(|e| GitError::Gix(e.to_string()))?;
        }

        let base = request.path.trim_matches('/').to_string();
        let mut entries = Vec::new();
        for entry in tree.iter() {
            let entry = entry?;
            let name = String::from_utf8_lossy(entry.filename()).into_owned();
            let path = if base.is_empty() {
                name.clone()
            } else {
                format!("{base}/{name}")
            };
            let kind = entry.kind();
            let hex = entry.id().to_string();
            entries.push(TreeEntry {
                name,
                path: path.clone(),
                oid: Some(self.oid_to_pb(hex)),
                r#type: entry_type(kind) as i32,
                mode: u32::from_str_radix(&format!("{:o}", entry.mode()), 8).unwrap_or(0),
                size: entry_size(&repo, entry.id().to_string().as_str()).unwrap_or(0),
            });

            if request.recursive && matches!(kind, EntryKind::Tree) {
                let child = self.list_tree(ListTreeRequest {
                    repository: request.repository.clone(),
                    revision: request.revision.clone(),
                    path,
                    recursive: true,
                    pagination: None,
                })?;
                entries.extend(child.entries);
            }
        }

        let (entries, page_info) = paginate::paginate(&entries, request.pagination.as_ref());
        Ok(ListTreeResponse {
            entries,
            page_info: Some(page_info),
            truncated: false,
        })
    }
}

fn entry_type(kind: EntryKind) -> tree_entry::EntryType {
    match kind {
        EntryKind::Tree => tree_entry::EntryType::TreeEntryTypeTree,
        EntryKind::Blob => tree_entry::EntryType::TreeEntryTypeBlob,
        EntryKind::BlobExecutable => tree_entry::EntryType::TreeEntryTypeExecutable,
        EntryKind::Link => tree_entry::EntryType::TreeEntryTypeSymlink,
        EntryKind::Commit => tree_entry::EntryType::TreeEntryTypeCommit,
    }
}

fn entry_size(repo: &gix::Repository, oid: &str) -> Option<i64> {
    let id = gix::hash::ObjectId::from_hex(oid.as_bytes()).ok()?;
    let object = repo.find_object(id).ok()?;
    object.data.len().try_into().ok()
}