//! Copyright (c) 2022-2026 GitDataAi All rights reserved.

use crate::bare::GitBare;
use crate::error::{GitError, GitResult};
use crate::pb::{Commit, ListCommitsRequest, ListCommitsResponse};
use crate::resolve_revision;

impl GitBare {
    pub fn list_commits(&self, request: ListCommitsRequest) -> GitResult<ListCommitsResponse> {
        let revision = resolve_revision!(request.revision.clone());

        let base_args = build_rev_list_args(self, &request, &revision)?;

        let total = {
            let mut args = base_args.clone();
            args.insert(3, "--count".into());
            let result = duct::cmd("git", &args)
                .stdout_capture()
                .stderr_capture()
                .unchecked()
                .run()?;
            if !result.status.success() {
                return Err(GitError::CommandFailed {
                    status_code: result.status.code(),
                    stderr: String::from_utf8_lossy(&result.stderr).into_owned(),
                });
            }
            String::from_utf8_lossy(&result.stdout)
                .trim()
                .parse::<usize>()
                .unwrap_or(0)
        };

        let page_size = request
            .pagination
            .as_ref()
            .map(|p| p.page_size as usize)
            .unwrap_or(total.max(1))
            .max(1);
        let start_offset = request
            .pagination
            .as_ref()
            .and_then(|p| {
                if p.page_token.is_empty() {
                    None
                } else {
                    p.page_token.parse::<usize>().ok()
                }
            })
            .unwrap_or(0)
            .min(total);

        let mut fetch_args = base_args;
        fetch_args.insert(3, format!("--skip={start_offset}"));
        fetch_args.insert(4, format!("-n{page_size}"));

        let result = duct::cmd("git", &fetch_args)
            .stdout_capture()
            .stderr_capture()
            .unchecked()
            .run()?;
        if !result.status.success() {
            return Err(GitError::CommandFailed {
                status_code: result.status.code(),
                stderr: String::from_utf8_lossy(&result.stderr).into_owned(),
            });
        }

        let page_ids: Vec<String> = String::from_utf8_lossy(&result.stdout)
            .lines()
            .map(str::trim)
            .filter(|line| !line.is_empty())
            .map(ToOwned::to_owned)
            .collect();

        let commits = if page_ids.is_empty() {
            Vec::new()
        } else {
            let repo = self.gix_repo()?;
            let mut commits = Vec::with_capacity(page_ids.len());
            for id in &page_ids {
                commits.push(read_commit_from_repo(self, &repo, id)?);
            }
            commits
        };

        let end = start_offset.saturating_add(page_ids.len());
        let has_next = end < total;
        let page_info = crate::pb::PageInfo {
            next_page_token: if has_next {
                end.to_string()
            } else {
                String::new()
            },
            has_next_page: has_next,
            total_count: total as u64,
        };

        Ok(ListCommitsResponse {
            commits,
            page_info: Some(page_info),
        })
    }
}

fn build_rev_list_args(
    gb: &GitBare,
    request: &ListCommitsRequest,
    revision: &str,
) -> GitResult<Vec<String>> {
    let mut args = vec![
        "--git-dir".to_string(),
        gb.bare_dir.to_string_lossy().into_owned(),
        "rev-list".into(),
    ];
    if request.first_parent {
        args.push("--first-parent".into());
    }
    if request.reverse {
        args.push("--reverse".into());
    }
    if request.max_parents > 0 {
        args.push(format!("--max-parents={}", request.max_parents));
    }
    if request.min_parents > 0 {
        args.push(format!("--min-parents={}", request.min_parents));
    }
    if let Some(since) = request.since.as_ref() {
        args.push(format!("--since=@{}", since.seconds));
    }
    if let Some(until) = request.until.as_ref() {
        args.push(format!("--until=@{}", until.seconds));
    }
    if request.all {
        args.push("--all".into());
    } else {
        args.push(revision.to_string());
    }
    if !request.path.is_empty() {
        crate::sanitize::validate_file_path(&request.path)?;
        args.push("--".into());
        args.push(request.path.clone());
    }
    Ok(args)
}

/// Read a single commit from an already-opened gix repo (no subprocess).
pub(crate) fn read_commit_from_repo(
    gb: &GitBare,
    repo: &gix::Repository,
    hex: &str,
) -> GitResult<Commit> {
    let id = gix::hash::ObjectId::from_hex(hex.as_bytes())
        .map_err(|e| crate::error::GitError::InvalidOid(e.to_string()))?;
    let commit = repo
        .find_object(id)?
        .try_into_commit()
        .map_err(|e| crate::error::GitError::Gix(e.to_string()))?;
    let tree_hex = commit.tree_id()?.to_string();
    let message = commit.message_raw()?.to_string();
    let (subject, body) = message
        .split_once('\n')
        .map(|(s, b)| (s.to_string(), b.trim_start_matches('\n').to_string()))
        .unwrap_or_else(|| (message.clone(), String::new()));
    let author_sig = commit.author().ok();
    let committer_sig = commit.committer().ok();
    Ok(Commit {
        oid: Some(gb.oid_to_pb(hex.to_string())),
        abbreviated_oid: commit
            .short_id()
            .map(|s| s.to_string())
            .unwrap_or_else(|_| hex.chars().take(7).collect()),
        parent_oids: commit
            .parent_ids()
            .map(|p| gb.oid_to_pb(p.to_string()))
            .collect(),
        tree_oid: Some(gb.oid_to_pb(tree_hex)),
        author: author_sig
            .as_ref()
            .map(crate::commit::get_commit::gix_sig_to_pb),
        committer: committer_sig
            .as_ref()
            .map(crate::commit::get_commit::gix_sig_to_pb),
        subject,
        body,
        message,
        trailers: Vec::new(),
        signature: None,
        stats: None,
        authored_at: author_sig.as_ref().map(|s| prost_types::Timestamp {
            seconds: s.seconds(),
            nanos: 0,
        }),
        committed_at: committer_sig.as_ref().map(|s| prost_types::Timestamp {
            seconds: s.seconds(),
            nanos: 0,
        }),
        raw: Vec::new(),
    })
}