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

use crate::api::response::{ApiErrorResponse, ApiResponse};
use crate::error::AppError;
use crate::models::issues::IssuePrRelation;
use crate::service::AppService;
use crate::service::issues::pr_relations::LinkPrParams;
use crate::session::Session;

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

#[derive(Debug, Deserialize, IntoParams)]
pub struct QueryParams {
    /// Maximum number of relations to return (default: 50, max: 100)
    pub limit: Option<i64>,
    /// Number of relations to skip for pagination (default: 0)
    pub offset: Option<i64>,
}

/// List pull request relations for an issue
///
/// Returns a paginated list of all pull requests linked to the given issue.
/// Shows relation type (closes, references, depends_on, etc.) and link metadata.
/// Requires read access to the issue.
#[utoipa::path(
    get,
    path = "/api/v1/workspaces/{workspace_name}/issues/{number}/prs",
    tag = "Issues",
    operation_id = "issueListPrRelations",
    params(PathParams, QueryParams),
    responses(
        (status = 200, description = "PR relations listed successfully. Returns array of PR relation objects.", body = ApiResponse<Vec<IssuePrRelation>>),
        (status = 401, description = "Authentication required or session expired", body = ApiErrorResponse),
        (status = 403, description = "Insufficient permissions to view this issue", body = ApiErrorResponse),
        (status = 404, description = "Issue not found", body = ApiErrorResponse),
        (status = 500, description = "Internal server error", body = ApiErrorResponse),
    ),
    security(
        ("session_cookie" = [])
    )
)]
pub async fn list_pr_relations(
    service: web::Data<AppService>,
    session: Session,
    path: web::Path<PathParams>,
    query: web::Query<QueryParams>,
) -> Result<HttpResponse, AppError> {
    let relations = service
        .issue
        .issue_pr_relations(
            &session,
            &path.workspace_name,
            path.number,
            query.limit.unwrap_or(50),
            query.offset.unwrap_or(0),
        )
        .await?;
    Ok(HttpResponse::Ok().json(ApiResponse::new(relations)))
}

/// Link a pull request to an issue
///
/// Creates a relation between the given issue and a pull request.
/// Commonly used to mark a PR as closing or referencing an issue.
/// Requires write access to the issue.
///
/// Parameters:
/// - pull_request_id: Pull request ID (UUID) to link
/// - relation_type: Relation type ("closes", "references", "depends_on", default: "references")
///
/// Returns the created relation.
#[utoipa::path(
    post,
    path = "/api/v1/workspaces/{workspace_name}/issues/{number}/prs",
    tag = "Issues",
    operation_id = "issueLinkPr",
    params(PathParams),
    request_body(
        content = LinkPrParams,
        description = "Link pull request parameters",
        content_type = "application/json"
    ),
    responses(
        (status = 200, description = "Pull request linked successfully. Returns the created relation.", body = ApiResponse<IssuePrRelation>),
        (status = 400, description = "Invalid parameters: invalid relation type", body = ApiErrorResponse),
        (status = 401, description = "Authentication required or session expired", body = ApiErrorResponse),
        (status = 403, description = "Insufficient permissions to edit this issue", body = ApiErrorResponse),
        (status = 404, description = "Issue or pull request not found", body = ApiErrorResponse),
        (status = 409, description = "Pull request is already linked to this issue", body = ApiErrorResponse),
        (status = 500, description = "Internal server error", body = ApiErrorResponse),
    ),
    security(
        ("session_cookie" = [])
    )
)]
pub async fn link_pr(
    service: web::Data<AppService>,
    session: Session,
    path: web::Path<PathParams>,
    params: web::Json<LinkPrParams>,
) -> Result<HttpResponse, AppError> {
    let relation = service
        .issue
        .issue_link_pr(
            &session,
            &path.workspace_name,
            path.number,
            params.into_inner(),
        )
        .await?;
    Ok(HttpResponse::Ok().json(ApiResponse::new(relation)))
}

#[derive(Debug, Deserialize, IntoParams)]
pub struct RelationPathParams {
    /// Workspace name (unique identifier)
    pub workspace_name: String,
    /// Issue number (unique within the workspace)
    pub number: i64,
    /// Relation ID (UUID)
    pub relation_id: uuid::Uuid,
}

/// Unlink a pull request from an issue
///
/// Removes a pull request relation from the given issue.
/// Requires write access to the issue.
///
/// Returns success message on completion.
#[utoipa::path(
    delete,
    path = "/api/v1/workspaces/{workspace_name}/issues/{number}/prs/{relation_id}",
    tag = "Issues",
    operation_id = "issueUnlinkPr",
    params(RelationPathParams),
    responses(
        (status = 200, description = "Pull request unlinked successfully.", body = ApiResponse<String>),
        (status = 401, description = "Authentication required or session expired", body = ApiErrorResponse),
        (status = 403, description = "Insufficient permissions to edit this issue", body = ApiErrorResponse),
        (status = 404, description = "PR relation not found", body = ApiErrorResponse),
        (status = 500, description = "Internal server error", body = ApiErrorResponse),
    ),
    security(
        ("session_cookie" = [])
    )
)]
pub async fn unlink_pr(
    service: web::Data<AppService>,
    session: Session,
    path: web::Path<RelationPathParams>,
) -> Result<HttpResponse, AppError> {
    service
        .issue
        .issue_unlink_pr(
            &session,
            &path.workspace_name,
            path.number,
            path.relation_id,
        )
        .await?;
    Ok(HttpResponse::Ok().json(ApiResponse::new("PR unlinked".to_string())))
}