imphnen-backend-service/imphnen-hackathon/src/join_requests/application/join_request_service.rs

use std::sync::Arc;
use uuid::Uuid;
use async_trait::async_trait;
use chrono::{Utc, TimeZone};
use imphnen_utils::errors::AppError;
use crate::join_requests::domain::entity::*;
use crate::join_requests::domain::repository::JoinRequestRepository;
use crate::join_requests::domain::service::JoinRequestService;

fn is_team_features_closed() -> bool {
    let deadline = Utc.with_ymd_and_hms(2025, 11, 30, 16, 59, 0).unwrap();
    Utc::now() >= deadline
}

pub struct JoinRequestServiceImpl {
    repo: Arc<dyn JoinRequestRepository>,
}

impl JoinRequestServiceImpl {
    pub fn new(repo: Arc<dyn JoinRequestRepository>) -> Self {
        Self { repo }
    }
}

#[async_trait]
impl JoinRequestService for JoinRequestServiceImpl {
    async fn create_join_request(
        &self,
        team_id: Uuid,
        user_id: Uuid,
        input: CreateJoinRequestInput,
    ) -> Result<JoinRequestWithDetails, AppError> {
        if is_team_features_closed() {
            return Err(AppError::BadRequestError(
                "Join requests are closed (deadline: November 30, 2025).".to_string(),
            ));
        }
        if !self.repo.team_exists(team_id).await? {
            return Err(AppError::NotFoundError("Team not found".to_string()));
        }
        if self.repo.team_has_submission(team_id).await? {
            return Err(AppError::BadRequestError("Cannot request to join a team that has already submitted".to_string()));
        }
        if let Some(active_team) = self.repo.user_active_team_name(user_id).await? {
            return Err(AppError::ConflictError(format!("You are already a member of team '{}'", active_team)));
        }
        let count = self.repo.active_member_count(team_id).await?;
        if count >= 5 {
            return Err(AppError::BadRequestError("Team is already full (max 5 members)".to_string()));
        }
        if self.repo.pending_request_exists(team_id, user_id).await? {
            return Err(AppError::ConflictError("You already have a pending request for this team".to_string()));
        }
        let id = Uuid::new_v4();
        let entity = self.repo.create(id, team_id, user_id, &input.message).await?;
        let details: Vec<JoinRequestWithDetails> = self.repo.find_by_user(user_id).await?;
        details.into_iter().find(|r| r.id == entity.id)
            .ok_or_else(|| AppError::InternalServerError("Failed to retrieve created join request".to_string()))
    }

    async fn get_my_join_requests(&self, user_id: Uuid) -> Result<Vec<JoinRequestWithDetails>, AppError> {
        self.repo.find_by_user(user_id).await
    }

    async fn get_team_join_requests(
        &self,
        team_id: Uuid,
        user_id: Uuid,
    ) -> Result<Vec<JoinRequestWithDetails>, AppError> {
        let leader_id = self.repo.get_team_leader_id(team_id).await?
            .ok_or_else(|| AppError::NotFoundError("Team not found".to_string()))?;
        if leader_id != user_id {
            return Err(AppError::ForbiddenError("Only the team leader can view join requests".to_string()));
        }
        self.repo.find_pending_by_team(team_id).await
    }

    async fn respond_to_join_request(
        &self,
        request_id: Uuid,
        user_id: Uuid,
        accept: bool,
    ) -> Result<(), AppError> {
        let request = self.repo.find_by_id(request_id).await?
            .ok_or_else(|| AppError::NotFoundError("Join request not found".to_string()))?;
        let leader_id = self.repo.get_team_leader_id(request.team_id).await?
            .ok_or_else(|| AppError::NotFoundError("Team not found".to_string()))?;
        if leader_id != user_id {
            return Err(AppError::ForbiddenError("Only the team leader can respond to join requests".to_string()));
        }
        if request.status != "pending" {
            return Err(AppError::BadRequestError("Join request is no longer pending".to_string()));
        }
        if accept {
            if is_team_features_closed() {
                return Err(AppError::BadRequestError("Team features are now closed".to_string()));
            }
            if self.repo.team_has_submission(request.team_id).await? {
                return Err(AppError::BadRequestError("Cannot accept join request after submitting a project".to_string()));
            }
            if let Some(active_team) = self.repo.user_active_team_name(request.user_id).await? {
                return Err(AppError::ConflictError(format!("User is already a member of team '{}'", active_team)));
            }
            let count = self.repo.active_member_count(request.team_id).await?;
            if count >= 5 {
                return Err(AppError::BadRequestError("Team is already full".to_string()));
            }
            self.repo.update_status(request_id, "accepted").await?;
            self.repo.add_team_member(request.team_id, request.user_id).await?;
            self.repo.reject_pending_invitations_for_user(request.user_id).await?;
            self.repo.reject_other_pending_for_user(request.user_id, request_id).await?;
        } else {
            self.repo.update_status(request_id, "rejected").await?;
        }
        Ok(())
    }
}