use crate::AppService;
use crate::error::AppError;
use crate::git::CommitMeta;
use crate::git::diff::{SideBySideDiffQuery, SideBySideDiffResponse};
use crate::project::activity::ActivityLogParams;
use chrono::Utc;
use models::projects::{MemberRole, project_members};
use models::pull_request::{PrStatus, pull_request};
use models::repos::repo;
use models::users::user;
use redis::AsyncCommands;
use sea_orm::*;
use serde::{Deserialize, Serialize};
use session::Session;
use utoipa::ToSchema;
use uuid::Uuid;

#[derive(Debug, Clone, Deserialize, ToSchema)]
pub struct PullRequestCreateRequest {
    pub title: String,
    pub body: Option<String>,
    pub base: String,
    pub head: String,
    #[serde(default)]
    pub draft: bool,
}

#[derive(Debug, Clone, Deserialize, ToSchema)]
pub struct PullRequestUpdateRequest {
    pub title: Option<String>,
    pub body: Option<String>,
    pub base: Option<String>,
    #[serde(default)]
    pub draft: Option<bool>,
}

#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
pub struct PullRequestResponse {
    pub repo: Uuid,
    pub number: i64,
    pub issue: Option<Uuid>,
    pub title: String,
    pub body: Option<String>,
    pub author: Uuid,
    pub author_username: Option<String>,
    pub base: String,
    pub head: String,
    pub status: String,
    pub merged_by: Option<Uuid>,
    pub created_at: chrono::DateTime<Utc>,
    pub updated_at: chrono::DateTime<Utc>,
    pub merged_at: Option<chrono::DateTime<Utc>>,
    pub created_by_ai: bool,
}

impl From<pull_request::Model> for PullRequestResponse {
    fn from(pr: pull_request::Model) -> Self {
        Self {
            repo: pr.repo,
            number: pr.number,
            issue: Some(pr.issue),
            title: pr.title,
            body: pr.body,
            author: pr.author,
            author_username: None,
            base: pr.base,
            head: pr.head,
            status: pr.status,
            merged_by: pr.merged_by,
            created_at: pr.created_at,
            updated_at: pr.updated_at,
            merged_at: pr.merged_at,
            created_by_ai: pr.created_by_ai,
        }
    }
}

#[derive(Debug, Clone, Serialize, ToSchema)]
pub struct PullRequestListResponse {
    pub pull_requests: Vec<PullRequestResponse>,
    pub total: u64,
    pub page: i64,
    pub per_page: i64,
}

#[derive(Debug, Clone, Serialize, ToSchema)]
pub struct PullRequestSummaryResponse {
    pub total: u64,
    pub open: u64,
    pub merged: u64,
    pub closed: u64,
}

#[derive(Debug, Clone, Serialize, ToSchema)]
pub struct PullRequestStatusResponse {
    pub status: String,
    pub can_merge: bool,
    pub merge_analysis: Option<MergeAnalysisResult>,
}

#[derive(Debug, Clone, Serialize, ToSchema)]
pub struct MergeAnalysisResult {
    pub is_fast_forward: bool,
    pub is_up_to_date: bool,
    pub is_normal: bool,
}

#[derive(Debug, Clone, Serialize, ToSchema)]
pub struct PrCommitResponse {
    pub oid: String,
    pub short_oid: String,
    pub message: String,
    pub summary: String,
    pub author_name: String,
    pub author_email: String,
    pub authored_at: chrono::DateTime<Utc>,
    pub committer_name: String,
    pub committer_email: String,
    pub committed_at: chrono::DateTime<Utc>,
}

impl From<CommitMeta> for PrCommitResponse {
    fn from(c: CommitMeta) -> Self {
        let oid_str = c.oid.to_string();
        fn sig_to_dt(time_secs: i64) -> chrono::DateTime<Utc> {
            chrono::DateTime::from_timestamp(time_secs, 0)
                .unwrap_or_else(|| chrono::DateTime::from_timestamp(0, 0).unwrap())
        }
        Self {
            oid: oid_str.clone(),
            short_oid: oid_str[..std::cmp::min(7, oid_str.len())].to_string(),
            message: c.message,
            summary: c.summary,
            author_name: c.author.name,
            author_email: c.author.email,
            authored_at: sig_to_dt(c.author.time_secs),
            committer_name: c.committer.name,
            committer_email: c.committer.email,
            committed_at: sig_to_dt(c.committer.time_secs),
        }
    }
}

#[derive(Debug, Clone, Serialize, ToSchema)]
pub struct PrCommitsListResponse {
    pub commits: Vec<PrCommitResponse>,
}

impl AppService {
    /// List pull requests for a repo.
    pub async fn pull_request_list(
        &self,
        namespace: String,
        repo_name: String,
        status: Option<String>,
        page: Option<i64>,
        per_page: Option<i64>,
        ctx: &Session,
    ) -> Result<PullRequestListResponse, AppError> {
        let repo = self.utils_find_repo(namespace, repo_name, ctx).await?;

        let page = page.unwrap_or(1);
        let per_page = per_page.unwrap_or(20);
        let offset = (page - 1) * per_page;

        let mut query = pull_request::Entity::find()
            .filter(pull_request::Column::Repo.eq(repo.id))
            .order_by_desc(pull_request::Column::CreatedAt);

        if let Some(ref s) = status {
            query = query.filter(pull_request::Column::Status.eq(s));
        }

        let total = query.clone().count(&self.db).await?;
        let prs = query
            .offset(offset as u64)
            .limit(per_page as u64)
            .all(&self.db)
            .await?;

        let author_ids: Vec<Uuid> = prs.iter().map(|p| p.author).collect();
        let authors = if author_ids.is_empty() {
            vec![]
        } else {
            user::Entity::find()
                .filter(user::Column::Uid.is_in(author_ids))
                .all(&self.db)
                .await?
        };

        let responses: Vec<PullRequestResponse> = prs
            .into_iter()
            .map(|pr| {
                let username = authors
                    .iter()
                    .find(|u| u.uid == pr.author)
                    .map(|u| u.username.clone());
                PullRequestResponse {
                    author_username: username,
                    ..PullRequestResponse::from(pr)
                }
            })
            .collect();

        Ok(PullRequestListResponse {
            pull_requests: responses,
            total,
            page,
            per_page,
        })
    }

    /// Get a single pull request.
    pub async fn pull_request_get(
        &self,
        namespace: String,
        repo_name: String,
        number: i64,
        ctx: &Session,
    ) -> Result<PullRequestResponse, AppError> {
        let repo = self.utils_find_repo(namespace, repo_name, ctx).await?;

        let cache_key = format!("pr:get:{}:{}", repo.id, number);
        if let Ok(mut conn) = self.cache.conn().await {
            if let Ok(cached) = conn.get::<_, String>(cache_key.clone()).await {
                if let Ok(cached) = serde_json::from_str::<PullRequestResponse>(&cached) {
                    return Ok(cached);
                }
            }
        }

        let pr = pull_request::Entity::find()
            .filter(pull_request::Column::Repo.eq(repo.id))
            .filter(pull_request::Column::Number.eq(number))
            .one(&self.db)
            .await?
            .ok_or(AppError::NotFound("Pull request not found".to_string()))?;

        let author = user::Entity::find_by_id(pr.author)
            .one(&self.db)
            .await
            .ok()
            .flatten();
        let username = author.map(|u| u.username);

        let response = PullRequestResponse {
            author_username: username,
            ..PullRequestResponse::from(pr)
        };

        if let Ok(mut conn) = self.cache.conn().await {
            let _: Option<()> = conn
                .set_ex::<String, String, ()>(
                    cache_key,
                    serde_json::to_string(&response).unwrap_or_default(),
                    300,
                )
                .await
                .ok();
        }

        Ok(response)
    }

    /// Get the next PR number for a repo.
    async fn next_pr_number(&self, repo_id: Uuid) -> Result<i64, AppError> {
        let max_num: Option<Option<i64>> = pull_request::Entity::find()
            .filter(pull_request::Column::Repo.eq(repo_id))
            .select_only()
            .column_as(pull_request::Column::Number.max(), "max_num")
            .into_tuple::<Option<i64>>()
            .one(&self.db)
            .await?;
        Ok(max_num.flatten().unwrap_or(0) + 1)
    }

    pub async fn pull_request_create(
        &self,
        namespace: String,
        repo_name: String,
        request: PullRequestCreateRequest,
        ctx: &Session,
    ) -> Result<PullRequestResponse, AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let repo: repo::Model = self
            .utils_check_repo_admin(namespace.clone(), repo_name.clone(), ctx)
            .await?;

        let number = self.next_pr_number(repo.id).await?;
        let now = Utc::now();

        let status = if request.draft {
            PrStatus::Draft
        } else {
            PrStatus::Open
        };

        let active = pull_request::ActiveModel {
            repo: Set(repo.id),
            number: Set(number),
            issue: Set(Uuid::now_v7()),
            title: Set(request.title),
            body: Set(request.body),
            author: Set(user_uid),
            base: Set(request.base),
            head: Set(request.head),
            status: Set(status.to_string()),
            merged_by: Set(None),
            created_at: Set(now),
            updated_at: Set(now),
            merged_at: Set(None),
            created_by_ai: Set(false),
            ..Default::default()
        };
        let model = active.insert(&self.db).await?;

        let actor_username = user::Entity::find_by_id(user_uid)
            .one(&self.db)
            .await
            .ok()
            .flatten()
            .map(|u| u.username)
            .unwrap_or_default();
        let _ = self
            .project_log_activity(
                repo.project,
                Some(repo.id),
                user_uid,
                super::super::project::activity::ActivityLogParams {
                    event_type: "pr_open".to_string(),
                    title: format!(
                        "{} opened pull request #{}: {}",
                        actor_username, number, model.title
                    ),
                    repo_id: Some(repo.id),
                    content: None,
                    event_id: None,
                    event_sub_id: Some(number),
                    metadata: Some(serde_json::json!({
                        "base": model.base,
                        "head": model.head,
                    })),
                    is_private: false,
                },
            )
            .await;

        if repo.ai_code_review_enabled && !request.draft {
            let this = self.clone();
            let namespace = namespace.clone();
            let repo_name = repo.repo_name.clone();
            let pr_number = Some(number);
            let repo_for_bg = repo.clone();
            tokio::spawn(async move {
                let _ = this
                    .trigger_ai_code_review_internal(
                        namespace,
                        repo_name,
                        pr_number,
                        None,
                        repo_for_bg,
                    )
                    .await;
            });
        }

        Ok(PullRequestResponse::from(model))
    }

    /// Update a PR (title, body, base, draft status).
    /// Only the PR author OR admin/owner can update.
    pub async fn pull_request_update(
        &self,
        namespace: String,
        repo_name: String,
        number: i64,
        request: PullRequestUpdateRequest,
        ctx: &Session,
    ) -> Result<PullRequestResponse, AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let repo: repo::Model = self
            .utils_check_repo_admin(namespace.clone(), repo_name.clone(), ctx)
            .await?;

        let pr = pull_request::Entity::find()
            .filter(pull_request::Column::Repo.eq(repo.id))
            .filter(pull_request::Column::Number.eq(number))
            .one(&self.db)
            .await?
            .ok_or(AppError::NotFound("Pull request not found".to_string()))?;

        // Permission: author OR admin/owner
        let is_author = pr.author == user_uid;
        let member = project_members::Entity::find()
            .filter(project_members::Column::Project.eq(repo.project))
            .filter(project_members::Column::User.eq(user_uid))
            .one(&self.db)
            .await?
            .ok_or(AppError::NoPower)?;
        let role = member.scope_role().map_err(|_| AppError::RoleParseError)?;
        let is_admin = role == MemberRole::Admin || role == MemberRole::Owner;

        if !is_author && !is_admin {
            return Err(AppError::NoPower);
        }

        // Cannot update a merged PR
        if pr.status == PrStatus::Merged.to_string() {
            return Err(AppError::BadRequest(
                "Cannot update a merged pull request".to_string(),
            ));
        }

        let mut active: pull_request::ActiveModel = pr.clone().into();
        if let Some(title) = request.title {
            active.title = Set(title);
        }
        if let Some(body) = request.body {
            active.body = Set(Some(body));
        }
        if let Some(base) = request.base {
            active.base = Set(base);
        }
        if let Some(draft) = request.draft {
            active.status = Set(if draft {
                PrStatus::Draft.to_string()
            } else {
                PrStatus::Open.to_string()
            });
        }
        active.updated_at = Set(Utc::now());

        let model = active.update(&self.db).await?;

        super::invalidate_pr_cache(&self.cache, repo.id, number).await;

        let actor_username = user::Entity::find_by_id(user_uid)
            .one(&self.db)
            .await
            .ok()
            .flatten()
            .map(|u| u.username)
            .unwrap_or_default();
        let _ = self
            .project_log_activity(
                repo.project,
                Some(repo.id),
                user_uid,
                super::super::project::activity::ActivityLogParams {
                    event_type: "pr_update".to_string(),
                    title: format!("{} updated pull request #{}", actor_username, number),
                    repo_id: Some(repo.id),
                    content: Some(model.title.clone()),
                    event_id: None,
                    event_sub_id: Some(number),
                    metadata: None,
                    is_private: false,
                },
            )
            .await;

        Ok(PullRequestResponse::from(model))
    }

    /// Close a pull request. Author OR admin/owner only.
    pub async fn pull_request_close(
        &self,
        namespace: String,
        repo_name: String,
        number: i64,
        ctx: &Session,
    ) -> Result<PullRequestResponse, AppError> {
        self.pr_set_status(namespace, repo_name, number, PrStatus::Closed, ctx)
            .await
    }

    /// Reopen a pull request. Author OR admin/owner only.
    pub async fn pull_request_reopen(
        &self,
        namespace: String,
        repo_name: String,
        number: i64,
        ctx: &Session,
    ) -> Result<PullRequestResponse, AppError> {
        self.pr_set_status(namespace, repo_name, number, PrStatus::Open, ctx)
            .await
    }

    pub async fn pull_request_delete(
        &self,
        namespace: String,
        repo_name: String,
        number: i64,
        ctx: &Session,
    ) -> Result<(), AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let repo: repo::Model = self
            .utils_check_repo_admin(namespace.clone(), repo_name.clone(), ctx)
            .await?;

        let pr = pull_request::Entity::find()
            .filter(pull_request::Column::Repo.eq(repo.id))
            .filter(pull_request::Column::Number.eq(number))
            .one(&self.db)
            .await?
            .ok_or(AppError::NotFound("Pull request not found".to_string()))?;

        // Permission: author OR admin/owner
        let is_author = pr.author == user_uid;
        let member = project_members::Entity::find()
            .filter(project_members::Column::Project.eq(repo.project))
            .filter(project_members::Column::User.eq(user_uid))
            .one(&self.db)
            .await?
            .ok_or(AppError::NoPower)?;
        let role = member.scope_role().map_err(|_| AppError::RoleParseError)?;
        let is_admin = role == MemberRole::Admin || role == MemberRole::Owner;

        if !is_author && !is_admin {
            return Err(AppError::NoPower);
        }

        // Cascade delete related records
        models::pull_request::PullRequestCommit::delete_many()
            .filter(models::pull_request::pull_request_commit::Column::Repo.eq(repo.id))
            .filter(models::pull_request::pull_request_commit::Column::Number.eq(number))
            .exec(&self.db)
            .await?;
        models::pull_request::PullRequestReview::delete_many()
            .filter(models::pull_request::pull_request_review::Column::Repo.eq(repo.id))
            .filter(models::pull_request::pull_request_review::Column::Number.eq(number))
            .exec(&self.db)
            .await?;
        models::pull_request::PullRequestReviewComment::delete_many()
            .filter(models::pull_request::pull_request_review_comment::Column::Repo.eq(repo.id))
            .filter(models::pull_request::pull_request_review_comment::Column::Number.eq(number))
            .exec(&self.db)
            .await?;

        pull_request::Entity::delete_by_id((repo.id, number))
            .exec(&self.db)
            .await?;

        super::invalidate_pr_cache(&self.cache, repo.id, number).await;

        let pr_title = pr.title.clone();
        let _ = self
            .project_log_activity(
                repo.project,
                Some(repo.id),
                user_uid,
                ActivityLogParams {
                    event_type: "pr_delete".to_string(),
                    title: format!(
                        "{} deleted pull request #{}: {}",
                        user_uid, number, pr_title
                    ),
                    repo_id: Some(repo.id),
                    content: Some(pr_title.clone()),
                    event_id: None,
                    event_sub_id: Some(number),
                    metadata: Some(serde_json::json!({
                        "pr_number": number,
                        "pr_title": pr_title,
                        "base": pr.base,
                        "head": pr.head,
                    })),
                    is_private: false,
                },
            )
            .await;

        Ok(())
    }

    /// Get PR summary counts.
    pub async fn pull_request_summary(
        &self,
        namespace: String,
        repo_name: String,
        ctx: &Session,
    ) -> Result<PullRequestSummaryResponse, AppError> {
        let repo = self.utils_find_repo(namespace, repo_name, ctx).await?;

        let total: u64 = pull_request::Entity::find()
            .filter(pull_request::Column::Repo.eq(repo.id))
            .count(&self.db)
            .await?;
        let open: u64 = pull_request::Entity::find()
            .filter(pull_request::Column::Repo.eq(repo.id))
            .filter(pull_request::Column::Status.eq(PrStatus::Open.to_string()))
            .count(&self.db)
            .await?;
        let merged: u64 = pull_request::Entity::find()
            .filter(pull_request::Column::Repo.eq(repo.id))
            .filter(pull_request::Column::Status.eq(PrStatus::Merged.to_string()))
            .count(&self.db)
            .await?;
        let closed: u64 = pull_request::Entity::find()
            .filter(pull_request::Column::Repo.eq(repo.id))
            .filter(pull_request::Column::Status.eq(PrStatus::Closed.to_string()))
            .count(&self.db)
            .await?;

        Ok(PullRequestSummaryResponse {
            total,
            open,
            merged,
            closed,
        })
    }

    async fn pr_set_status(
        &self,
        namespace: String,
        repo_name: String,
        number: i64,
        status: PrStatus,
        ctx: &Session,
    ) -> Result<PullRequestResponse, AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let repo: repo::Model = self
            .utils_check_repo_admin(namespace.clone(), repo_name.clone(), ctx)
            .await?;

        let pr = pull_request::Entity::find()
            .filter(pull_request::Column::Repo.eq(repo.id))
            .filter(pull_request::Column::Number.eq(number))
            .one(&self.db)
            .await?
            .ok_or(AppError::NotFound("Pull request not found".to_string()))?;

        // Permission: author OR admin/owner
        let is_author = pr.author == user_uid;
        let member = project_members::Entity::find()
            .filter(project_members::Column::Project.eq(repo.project))
            .filter(project_members::Column::User.eq(user_uid))
            .one(&self.db)
            .await?
            .ok_or(AppError::NoPower)?;
        let role = member.scope_role().map_err(|_| AppError::RoleParseError)?;
        let is_admin = role == MemberRole::Admin || role == MemberRole::Owner;

        if !is_author && !is_admin {
            return Err(AppError::NoPower);
        }

        if pr.status == PrStatus::Merged.to_string() {
            return Err(AppError::BadRequest(
                "Cannot modify a merged pull request".to_string(),
            ));
        }

        let mut active: pull_request::ActiveModel = pr.clone().into();
        active.status = Set(status.to_string());
        active.updated_at = Set(Utc::now());
        let model = active.update(&self.db).await?;

        super::invalidate_pr_cache(&self.cache, repo.id, number).await;

        let actor_username = user::Entity::find_by_id(user_uid)
            .one(&self.db)
            .await
            .ok()
            .flatten()
            .map(|u| u.username)
            .unwrap_or_default();
        let event_type = if status == PrStatus::Closed {
            "pr_close"
        } else {
            "pr_reopen"
        };
        let _ = self
            .project_log_activity(
                repo.project,
                Some(repo.id),
                user_uid,
                super::super::project::activity::ActivityLogParams {
                    event_type: event_type.to_string(),
                    title: format!(
                        "{} {} pull request #{}",
                        actor_username,
                        if status == PrStatus::Closed {
                            "closed"
                        } else {
                            "reopened"
                        },
                        number
                    ),
                    repo_id: Some(repo.id),
                    content: Some(model.title.clone()),
                    event_id: None,
                    event_sub_id: Some(number),
                    metadata: None,
                    is_private: false,
                },
            )
            .await;

        Ok(PullRequestResponse::from(model))
    }

    /// List all commits in a pull request (from base..head).
    pub async fn pr_commits_list(
        &self,
        namespace: String,
        repo_name: String,
        pr_number: i64,
        ctx: &Session,
    ) -> Result<PrCommitsListResponse, AppError> {
        let repo = self
            .utils_find_repo(namespace.clone(), repo_name.clone(), ctx)
            .await?;

        let pr = pull_request::Entity::find()
            .filter(pull_request::Column::Repo.eq(repo.id))
            .filter(pull_request::Column::Number.eq(pr_number))
            .one(&self.db)
            .await?
            .ok_or(AppError::NotFound("Pull request not found".to_string()))?;

        // Clone repo once so it can be used in both spawn_blocking calls
        let repo_for_base = repo.clone();
        let repo_for_commits = repo.clone();

        let (base_oid, head_oid) = tokio::task::spawn_blocking({
            let pr = pr.clone();
            move || {
                let domain = crate::git::GitDomain::from_model(repo_for_base)?;

                let base_ref = if pr.base.starts_with("refs/") {
                    pr.base.clone()
                } else {
                    format!("refs/heads/{}", pr.base)
                };
                let head_ref = if pr.head.starts_with("refs/") {
                    pr.head.clone()
                } else {
                    format!("refs/heads/{}", pr.head)
                };

                let base_oid = domain
                    .ref_target(&base_ref)
                    .map_err(|e| crate::git::GitError::Internal(e.to_string()))?
                    .ok_or_else(|| {
                        crate::git::GitError::NotFound(format!(
                            "Base branch '{}' not found",
                            pr.base
                        ))
                    })?;

                let head_oid = domain
                    .ref_target(&head_ref)
                    .map_err(|e| crate::git::GitError::Internal(e.to_string()))?
                    .ok_or_else(|| {
                        crate::git::GitError::NotFound(format!(
                            "Head branch '{}' not found",
                            pr.head
                        ))
                    })?;

                Ok::<_, crate::git::GitError>((base_oid, head_oid))
            }
        })
        .await
        .map_err(|e| AppError::InternalServerError(format!("Task join error: {e}")))?
        .map_err(AppError::from)?;

        let commits = tokio::task::spawn_blocking(move || {
            let domain = crate::git::GitDomain::from_model(repo_for_commits)?;
            let range = format!("{}..{}", base_oid, head_oid);
            let metas = domain.commit_log(Some(&range), 0, 500)?;
            Ok::<_, crate::git::GitError>(metas)
        })
        .await
        .map_err(|e| AppError::InternalServerError(format!("Task join error: {e}")))?
        .map_err(AppError::from)?;

        let commits: Vec<PrCommitResponse> =
            commits.into_iter().map(PrCommitResponse::from).collect();

        Ok(PrCommitsListResponse { commits })
    }

    /// Get the side-by-side diff for a pull request.
    ///
    /// Resolves the PR's base and head branch refs to commit OIDs and
    /// generates a side-by-side diff suitable for UI rendering.
    pub async fn pr_diff_side_by_side(
        &self,
        namespace: String,
        repo_name: String,
        pr_number: i64,
        query: SideBySideDiffQuery,
        ctx: &Session,
    ) -> Result<SideBySideDiffResponse, AppError> {
        let repo = self
            .utils_find_repo(namespace.clone(), repo_name.clone(), ctx)
            .await?;

        let pr = pull_request::Entity::find()
            .filter(pull_request::Column::Repo.eq(repo.id))
            .filter(pull_request::Column::Number.eq(pr_number))
            .one(&self.db)
            .await?
            .ok_or(AppError::NotFound("Pull request not found".to_string()))?;

        let (base_oid, head_oid) = tokio::task::spawn_blocking(move || {
            let domain = crate::git::GitDomain::from_model(repo)?;

            let base_oid = domain
                .branch_target(&pr.base)
                .map_err(|e| crate::git::GitError::Internal(e.to_string()))?
                .ok_or_else(|| {
                    crate::git::GitError::NotFound(format!("Branch '{}' not found", pr.base))
                })?;

            let head_oid = domain
                .branch_target(&pr.head)
                .map_err(|e| crate::git::GitError::Internal(e.to_string()))?
                .ok_or_else(|| {
                    crate::git::GitError::NotFound(format!("Branch '{}' not found", pr.head))
                })?;

            Ok::<_, crate::git::GitError>((base_oid, head_oid))
        })
        .await
        .map_err(|e| AppError::InternalServerError(format!("Task join error: {e}")))?
        .map_err(AppError::from)?;

        let diff_query = SideBySideDiffQuery {
            base: base_oid.to_string(),
            head: head_oid.to_string(),
            pathspec: query.pathspec,
            context_lines: query.context_lines,
        };

        self.git_diff_side_by_side(namespace, repo_name, diff_query, ctx)
            .await
    }
}