use std::io::Write;

use crate::bare::GitBare;
use crate::error::{GitError, GitResult};
use crate::pb::{IndexPackRequest, IndexPackResponse};

impl GitBare {
    /// Index a pack file from streamed input.
    ///
    /// Client-streaming → unary response.
    /// Collects all input chunks into a single pack, then runs `git index-pack`.
    pub fn index_pack(&self, inputs: Vec<IndexPackRequest>) -> GitResult<IndexPackResponse> {
        // Reassemble all chunks into a single pack data buffer
        let mut pack_data = Vec::new();
        let mut strict = false;
        let mut keep = false;

        for input in &inputs {
            pack_data.extend_from_slice(&input.data);
            if input.strict {
                strict = true;
            }
            if input.keep {
                keep = true;
            }
        }

        if pack_data.is_empty() {
            return Err(GitError::InvalidArgument("empty pack data".into()));
        }

        let pack_dir = self.bare_dir.join("objects").join("pack");
        std::fs::create_dir_all(&pack_dir).map_err(GitError::Io)?;

        // Write pack data to a unique temp file in the pack directory.
        let mut tmp_file = tempfile::Builder::new()
            .prefix("tmp_index_pack_")
            .tempfile_in(&pack_dir)
            .map_err(GitError::Io)?;
        tmp_file.write_all(&pack_data).map_err(GitError::Io)?;
        let tmp_path = tmp_file.path().to_path_buf();

        let mut args = vec![
            "--git-dir".to_string(),
            self.bare_dir.to_string_lossy().into_owned(),
            "index-pack".to_string(),
        ];
        if strict {
            args.push("--strict".into());
        }
        if keep {
            args.push("--keep".into());
        }
        args.push(tmp_path.to_string_lossy().into_owned());

        let result = duct::cmd("git", &args)
            .stdout_capture()
            .stderr_capture()
            .unchecked()
            .run()?;

        drop(tmp_file);

        if !result.status.success() {
            return Err(GitError::CommandFailed {
                status_code: result.status.code(),
                stderr: String::from_utf8_lossy(&result.stderr).into_owned(),
            });
        }

        // Parse the output to extract the pack hash
        let output = String::from_utf8_lossy(&result.stdout);
        let stderr = String::from_utf8_lossy(&result.stderr);
        let all_output = format!("{output}\n{stderr}");

        // git index-pack outputs the .idx and .pack filenames
        // e.g. "... pack-<hex>.pack  ...  pack-<hex>.idx"
        let pack_hash = all_output
            .lines()
            .filter_map(|line| {
                // Look for the hash after "pack-" and before ".idx" or ".pack"
                let trimmed = line.trim();
                if let Some(idx) = trimmed.find("pack-") {
                    let rest = &trimmed[idx + 5..];
                    if let Some(end) = rest.find('.') {
                        let hex = &rest[..end];
                        if hex.len() == 40 || hex.len() == 64 {
                            return Some(hex.to_string());
                        }
                    }
                }
                None
            })
            .next();

        // Try to get object count from .idx if it exists
        let mut object_count = 0u64;
        if let Some(ref hash) = pack_hash {
            let idx_path = pack_dir.join(format!("pack-{}.idx", hash));
            if idx_path.exists() {
                let verify = duct::cmd(
                    "git",
                    [
                        "--git-dir",
                        self.bare_dir.to_string_lossy().as_ref(),
                        "verify-pack",
                        "-v",
                        idx_path.to_string_lossy().as_ref(),
                    ],
                )
                .stdout_capture()
                .stderr_capture()
                .unchecked()
                .run();
                if let Ok(v) = verify {
                    let out = String::from_utf8_lossy(&v.stdout);
                    object_count = out
                        .lines()
                        .filter(|l| {
                            let parts: Vec<&str> = l.split_whitespace().collect();
                            parts.len() >= 3
                                && parts
                                    .first()
                                    .map(|s| s.len() == 40 || s.len() == 64)
                                    .unwrap_or(false)
                        })
                        .count() as u64;
                }
            }
        }

        Ok(IndexPackResponse {
            pack_hash: pack_hash.map(|h| self.oid_to_pb(h)),
            object_count,
            stderr: stderr.into_owned(),
        })
    }
}