use actix_web::{HttpResponse, web};
use serde::Deserialize;
use utoipa::IntoParams;

use crate::api::response::{ApiErrorResponse, ApiResponse};
use crate::error::AppError;
use crate::models::prs::PullRequest;
use crate::service::AppService;
use crate::service::pr::core::MergePrParams;
use crate::session::Session;

#[derive(Debug, Deserialize, IntoParams)]
pub struct PathParams {
    /// Workspace name (unique identifier)
    pub workspace_name: String,
    /// Repository name (unique within the workspace)
    pub repo_name: String,
    /// PR number (unique within the repository)
    pub number: i64,
}

/// Merge a pull request
///
/// Merges the source branch into the target branch.
/// Requires at least Maintainer role in the repository.
///
/// Branch protection rules are enforced:
/// - Required approvals count (self-approval not allowed)
/// - Required status checks must pass
/// - Admins can bypass protection rules
///
/// Parameters:
/// - strategy: Merge strategy ("merge", "squash", "rebase", default: "merge")
/// - squash_title: Custom title for squash merge (optional)
/// - squash_message: Custom message for squash merge (optional)
/// - delete_source_branch: Delete source branch after merge (optional, only same-repo)
///
/// Returns the merged PR with merge commit SHA.
#[utoipa::path(
    post,
    path = "/api/v1/workspaces/{workspace_name}/repos/{repo_name}/prs/{number}/merge",
    tag = "Pull Requests",
    operation_id = "prMerge",
    params(PathParams),
    request_body(
        content = MergePrParams,
        description = "Merge parameters",
        content_type = "application/json"
    ),
    responses(
        (status = 200, description = "PR merged successfully. Returns the merged PR with merge commit SHA.", body = ApiResponse<PullRequest>),
        (status = 400, description = "Cannot merge: PR not open, is draft, or branch protection requirements not met", body = ApiErrorResponse),
        (status = 401, description = "Authentication required or session expired", body = ApiErrorResponse),
        (status = 403, description = "Insufficient permissions (requires Maintainer role or higher)", body = ApiErrorResponse),
        (status = 404, description = "PR not found", body = ApiErrorResponse),
        (status = 500, description = "Internal server error or git merge failure", body = ApiErrorResponse),
    ),
    security(
        ("session_cookie" = [])
    )
)]
pub async fn merge(
    service: web::Data<AppService>,
    session: Session,
    path: web::Path<PathParams>,
    params: web::Json<MergePrParams>,
) -> Result<HttpResponse, AppError> {
    let pr = service
        .pr
        .pr_merge(
            &session,
            &path.workspace_name,
            &path.repo_name,
            path.number,
            params.into_inner(),
        )
        .await?;
    Ok(HttpResponse::Ok().json(ApiResponse::new(pr)))
}