use crate::error::GitResult;
use crate::pb::*;

/// Discover remote refs via `git ls-remote`.
pub fn find_remote_repository(
    request: FindRemoteRepositoryRequest,
) -> GitResult<FindRemoteRepositoryResponse> {
    if request.remote_url.is_empty() {
        return Ok(FindRemoteRepositoryResponse {
            refs: vec![],
            exists: false,
        });
    }

    let output = std::process::Command::new("git")
        .args(["ls-remote", "--symref", &request.remote_url])
        .stdout(std::process::Stdio::piped())
        .stderr(std::process::Stdio::piped())
        .output()
        .map_err(|e| crate::error::GitError::CommandFailed {
            status_code: None,
            stderr: e.to_string(),
        })?;

    if !output.status.success() {
        let stderr = String::from_utf8_lossy(&output.stderr);
        if stderr.contains("Could not resolve host") || stderr.contains("Repository not found") {
            return Ok(FindRemoteRepositoryResponse {
                refs: vec![],
                exists: false,
            });
        }
        return Ok(FindRemoteRepositoryResponse {
            refs: vec![],
            exists: false,
        });
    }

    let stdout = String::from_utf8_lossy(&output.stdout);
    let mut refs = Vec::new();

    for line in stdout.lines() {
        let line = line.trim();
        if line.is_empty() {
            continue;
        }

        // Lines can be:
        // SHA<TAB>refname           (direct ref)
        // ref: refs/heads/main<TAB>HEAD  (symbolic ref via --symref)
        if line.starts_with("ref:") {
            if let Some((target, name)) = line.split_once('\t') {
                refs.push(RemoteHead {
                    ref_name: name.to_string(),
                    target_oid: String::new(),
                    symbolic: true,
                    symbolic_target: target
                        .strip_prefix("ref:")
                        .unwrap_or(target)
                        .trim()
                        .to_string(),
                });
            }
        } else if let Some((oid, name)) = line.split_once('\t') {
            refs.push(RemoteHead {
                ref_name: name.to_string(),
                target_oid: oid.to_string(),
                symbolic: false,
                symbolic_target: String::new(),
            });
        }
    }

    Ok(FindRemoteRepositoryResponse { refs, exists: true })
}

/// Find the root ref (HEAD) of a remote repository.
pub fn find_remote_root_ref(
    request: FindRemoteRootRefRequest,
) -> GitResult<FindRemoteRootRefResponse> {
    let output = std::process::Command::new("git")
        .args(["ls-remote", "--symref", &request.remote_url, "HEAD"])
        .stdout(std::process::Stdio::piped())
        .stderr(std::process::Stdio::piped())
        .output()
        .map_err(|e| crate::error::GitError::CommandFailed {
            status_code: None,
            stderr: e.to_string(),
        })?;

    let stdout = String::from_utf8_lossy(&output.stdout);
    for line in stdout.lines() {
        let line = line.trim();
        if line.starts_with("ref:") {
            if let Some((target, _name)) = line.split_once('\t') {
                let ref_name = target
                    .strip_prefix("ref:")
                    .unwrap_or(target)
                    .trim()
                    .to_string();
                return Ok(FindRemoteRootRefResponse {
                    ref_name,
                    target_oid: String::new(),
                });
            }
        } else if let Some((oid, name)) = line.split_once('\t') {
            return Ok(FindRemoteRootRefResponse {
                ref_name: name.to_string(),
                target_oid: oid.to_string(),
            });
        }
    }

    Ok(FindRemoteRootRefResponse::default())
}