use crate::bare::GitBare;
use crate::error::GitResult;
use crate::paginate;
use crate::pb::*;

impl GitBare {
    /// Find all refs pointing to a given OID.
    pub fn find_refs_by_oid(&self, request: FindRefsByOidRequest) -> GitResult<FindRefsByOidResponse> {
        crate::sanitize::validate_revision(&request.oid)?;

        let mut args = vec![
            "--git-dir".to_string(),
            self.bare_dir.to_string_lossy().into_owned(),
            "for-each-ref".to_string(),
            "--format=%(refname)%00%(objectname)%00%(symref)".to_string(),
            format!("--points-at={}", request.oid),
        ];

        if let Some(ref filter) = request.filter {
            for prefix in &filter.prefixes {
                args.push(prefix.clone());
            }
            if filter.limit > 0 {
                args.push(format!("--count={}", filter.limit));
            }
        }

        let output = std::process::Command::new("git")
            .args(&args)
            .output()
            .map_err(|e| crate::error::GitError::CommandFailed {
                status_code: None,
                stderr: e.to_string(),
            })?;

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

        for line in stdout.lines() {
            let parts: Vec<&str> = line.split('\0').collect();
            if parts.len() >= 2 {
                let ref_name = parts[0].to_string();
                let oid = parts[1].to_string();
                let symref = parts.get(2).map(|s| s.to_string()).unwrap_or_default();
                refs.push(FoundRef {
                    ref_name,
                    target_oid: oid,
                    symbolic: !symref.is_empty(),
                    symbolic_target: symref,
                });
            }
        }

        Ok(FindRefsByOidResponse { refs })
    }

    /// List refs with optional prefix/pagination/sorting.
    pub fn list_all_refs(&self, request: ListRefsRequest) -> GitResult<ListRefsResponse> {
        let mut args = vec![
            "--git-dir".to_string(),
            self.bare_dir.to_string_lossy().into_owned(),
            "for-each-ref".to_string(),
            "--format=%(refname)%00%(objectname)%00%(symref)".to_string(),
        ];

        // Sort direction
        let sort_prefix = match SortDirection::try_from(request.sort_direction) {
            Ok(SortDirection::Asc) => "",
            Ok(SortDirection::Desc) | _ => "-",
        };
        args.push(format!("--sort={sort_prefix}refname"));

        // Containing OIDs filter
        if let Some(first_oid) = request.containing_oids.first() {
            args.push(format!("--points-at={first_oid}"));
        }

        // Prefix or pattern
        if !request.prefixes.is_empty() {
            for prefix in &request.prefixes {
                args.push(prefix.clone());
            }
        }

        let output = std::process::Command::new("git")
            .args(&args)
            .output()
            .map_err(|e| crate::error::GitError::CommandFailed {
                status_code: None,
                stderr: e.to_string(),
            })?;

        let stdout = String::from_utf8_lossy(&output.stdout);
        let mut all_refs: Vec<FoundRef> = Vec::new();

        for line in stdout.lines() {
            let parts: Vec<&str> = line.split('\0').collect();
            if parts.len() >= 2 {
                let ref_name = parts[0].to_string();
                let oid = parts[1].to_string();
                let symref = parts.get(2).map(|s| s.to_string()).unwrap_or_default();

                // Apply glob pattern filter if set
                if !request.pattern.is_empty() && !simple_glob_match(&request.pattern, &ref_name) {
                    continue;
                }

                all_refs.push(FoundRef {
                    ref_name,
                    target_oid: oid,
                    symbolic: !symref.is_empty(),
                    symbolic_target: symref,
                });
            }
        }

        let _total = all_refs.len() as u64;
        let (paged, page_info) = paginate::paginate(&all_refs, request.pagination.as_ref());

        Ok(ListRefsResponse {
            refs: paged,
            page_info: Some(page_info),
        })
    }
}

/// Simple glob match. Supports `*` (any chars) and `?` (single char).
fn simple_glob_match(pattern: &str, name: &str) -> bool {
    let pat_bytes = pattern.as_bytes();
    let name_bytes = name.as_bytes();
    let mut pi = 0;
    let mut ni = 0;
    let mut star_pi = None;
    let mut star_ni = 0;

    while ni < name_bytes.len() || pi < pat_bytes.len() {
        if pi < pat_bytes.len() && pat_bytes[pi] == b'*' {
            star_pi = Some(pi);
            star_ni = ni;
            pi += 1;
        } else if pi < pat_bytes.len() && ni < name_bytes.len()
            && (pat_bytes[pi] == b'?' || pat_bytes[pi] == name_bytes[ni])
        {
            pi += 1;
            ni += 1;
        } else if let Some(sp) = star_pi {
            pi = sp + 1;
            star_ni += 1;
            ni = star_ni;
        } else {
            return false;
        }
    }
    true
}