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

use crate::api::response::{ApiErrorResponse, ApiResponse};
use crate::error::AppError;
use crate::models::base_info::{self, UserBaseInfo};
use crate::models::prs::PullRequestDetail;
use crate::service::AppService;
use crate::service::pr::core::CreatePrParams;
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,
}

/// Create a pull request
///
/// Creates a new pull request proposing changes from a source branch to a target branch.
/// Requires at least Member role in the repository.
///
/// Parameters:
/// - title: PR title (required)
/// - body: PR description in markdown (optional)
/// - source_repo_id: Source repository ID (supports cross-repo PRs from forks)
/// - source_branch: Source branch name (must exist)
/// - target_branch: Target branch name (must exist in the repo)
/// - head_commit_sha: Head commit SHA from the source branch
/// - base_commit_sha: Base commit SHA for diff calculation (optional)
/// - draft: Whether this is a draft PR (optional, defaults to false)
///
/// Effects:
/// - PR is created with auto-incrementing number
/// - PR status tracking is initialized
/// - Author is automatically subscribed
/// - Repository stats are updated
///
/// Returns the created PR with full metadata.
#[utoipa::path(
    post,
    path = "/api/v1/workspaces/{workspace_name}/repos/{repo_name}/prs",
    tag = "Pull Requests",
    operation_id = "prCreate",
    params(PathParams),
    request_body(
        content = CreatePrParams,
        description = "PR creation parameters",
        content_type = "application/json"
    ),
    responses(
        (status = 201, description = "PR created successfully. Returns the newly created PR with full metadata.", body = ApiResponse<PullRequestDetail>),
        (status = 400, description = "Invalid parameters: empty title, non-existent branch/commit, or invalid fork relationship", body = ApiErrorResponse),
        (status = 401, description = "Authentication required or session expired", body = ApiErrorResponse),
        (status = 403, description = "Insufficient permissions (requires Member role or higher)", body = ApiErrorResponse),
        (status = 404, description = "Repository or workspace not found", body = ApiErrorResponse),
        (status = 500, description = "Internal server error", body = ApiErrorResponse),
    ),
    security(
        ("session_cookie" = [])
    )
)]
pub async fn create(
    service: web::Data<AppService>,
    session: Session,
    path: web::Path<PathParams>,
    params: web::Json<CreatePrParams>,
) -> Result<HttpResponse, AppError> {
    let pr = service
        .pr
        .pr_create(
            &session,
            &path.workspace_name,
            &path.repo_name,
            params.into_inner(),
        )
        .await?;
    let author_id = pr.author_id;
    let users = base_info::resolve_users(&service.ctx.db, &[author_id]).await?;
    let author = users
        .get(&author_id)
        .cloned()
        .unwrap_or_else(|| UserBaseInfo::placeholder(author_id));
    Ok(HttpResponse::Created().json(ApiResponse::new(pr.into_detail(author))))
}