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

use crate::bare::GitBare;
use crate::commit::create_commit::command_ok;
use crate::error::{GitError, GitResult};
use crate::pb::{CherryPickCommitRequest, CreateCommitResponse, GetCommitRequest};

const MAX_CHERRY_PICK_PATCH_BYTES: usize = 100 * 1024 * 1024;

impl GitBare {
    pub fn cherry_pick_commit(
        &self,
        request: CherryPickCommitRequest,
    ) -> GitResult<CreateCommitResponse> {
        let target_branch = request.branch.clone();
        crate::sanitize::validate_ref_name(&target_branch)?;
        let cp_revision = match request.commit.and_then(|s| s.selector) {
            Some(crate::pb::object_selector::Selector::Oid(oid)) => {
                crate::sanitize::validate_oid_hex(&oid.hex)?;
                oid.hex
            }
            Some(crate::pb::object_selector::Selector::Revision(name)) => {
                crate::sanitize::validate_revision(&name.revision)?;
                name.revision
            }
            None => return Err(GitError::InvalidArgument("commit is required".into())),
        };

        let repo = self.gix_repo()?;

        let branch_ref = format!("refs/heads/{}", target_branch);
        let branch_tip = repo
            .find_reference(branch_ref.as_str())
            .ok()
            .and_then(|mut r| r.peel_to_id().ok())
            .map(|id| id.to_string())
            .ok_or_else(|| GitError::RefNotFound(target_branch.clone()))?;

        let cp_id = repo.rev_parse_single(cp_revision.as_str())?;
        let cp_obj = cp_id
            .object()?
            .try_into_commit()
            .map_err(|e| GitError::Gix(e.to_string()))?;
        let parent_id = cp_obj.parent_ids().next().map(|p| p.to_string());

        let tmp_index = tempfile::Builder::new()
            .prefix("gitks-cp-")
            .tempfile_in(&self.bare_dir)?;
        let idx_path = tmp_index.path().to_string_lossy().into_owned();
        let bare = self.bare_dir.to_string_lossy().into_owned();

        let read_tree = duct::cmd(
            "git",
            ["--git-dir", bare.as_str(), "read-tree", branch_tip.as_str()],
        )
        .env("GIT_INDEX_FILE", &idx_path)
        .stdout_capture()
        .stderr_capture()
        .unchecked()
        .run()?;
        command_ok(read_tree)?;

        let mut format_patch_args = vec![
            "--git-dir".to_string(),
            bare.clone(),
            "format-patch".to_string(),
            "--stdout".to_string(),
            "--full-index".to_string(),
            "--binary".to_string(),
            "-1".to_string(),
        ];
        if parent_id.is_none() {
            format_patch_args.push("--root".to_string());
        }
        format_patch_args.push(cp_revision.clone());

        let diff = duct::cmd("git", &format_patch_args)
            .env("GIT_INDEX_FILE", &idx_path)
            .stdout_capture()
            .stderr_capture()
            .unchecked()
            .run()?;
        let patch_data = command_ok(diff)?;
        if patch_data.len() > MAX_CHERRY_PICK_PATCH_BYTES {
            return Err(GitError::InvalidArgument(format!(
                "cherry-pick patch too large ({} bytes, max {MAX_CHERRY_PICK_PATCH_BYTES})",
                patch_data.len()
            )));
        }

        let apply = duct::cmd(
            "git",
            [
                "--git-dir",
                bare.as_str(),
                "apply",
                "--cached",
                "--allow-empty",
                "-",
            ],
        )
        .env("GIT_INDEX_FILE", &idx_path)
        .stdin_bytes(patch_data.as_bytes())
        .stdout_capture()
        .stderr_capture()
        .unchecked()
        .run()?;
        if !apply.status.success() {
            return Err(GitError::Internal(format!(
                "cherry-pick apply failed: {}",
                String::from_utf8_lossy(&apply.stderr)
            )));
        }

        let write_tree = duct::cmd("git", ["--git-dir", bare.as_str(), "write-tree"])
            .env("GIT_INDEX_FILE", &idx_path)
            .stdout_capture()
            .stderr_capture()
            .unchecked()
            .run()?;
        let tree_id = command_ok(write_tree)?.trim().to_string();

        let message = cp_obj.message_raw()?.to_string();

        let parents = vec![branch_tip.clone()];
        let commit_id = self.commit_tree(
            &tree_id,
            &parents,
            &message,
            request.committer.as_ref(),
            request.committer.as_ref(),
        )?;

        self.update_branch_ref(&target_branch, &commit_id, Some(&branch_tip), false)?;

        Ok(CreateCommitResponse {
            commit: Some(self.get_commit(GetCommitRequest {
                repository: request.repository,
                revision: Some(crate::pb::ObjectSelector {
                    selector: Some(crate::pb::object_selector::Selector::Revision(
                        crate::pb::ObjectName {
                            revision: commit_id,
                        },
                    )),
                }),
                include_stats: false,
                include_raw: false,
            })?),
            branch: target_branch,
        })
    }

    pub(crate) fn update_branch_ref(
        &self,
        branch: &str,
        commit_id: &str,
        old_value: Option<&str>,
        force: bool,
    ) -> GitResult<()> {
        let refname = format!("refs/heads/{}", branch);
        let mut args = vec![
            "--git-dir".to_string(),
            self.bare_dir.to_string_lossy().into_owned(),
            "update-ref".into(),
            refname,
            commit_id.to_string(),
        ];
        if !force {
            args.push(old_value.unwrap_or(crate::oid::ZERO_OID).to_string());
        }
        let update = duct::cmd("git", &args)
            .stdout_capture()
            .stderr_capture()
            .unchecked()
            .run()?;
        command_ok(update).map(|_| ())
    }
}