use super::{DateTime, Result, UserId, Utc, async_trait};

/// Aggregated statistics for the dashboard.
#[derive(Debug, Clone, serde::Serialize)]
pub struct DashboardStats {
    /// Number of tasks due today.
    pub tasks_due_today: i64,
    /// Number of tasks due within the next 7 days.
    pub tasks_due_this_week: i64,
    /// Number of overdue tasks.
    pub overdue_count: i64,
    /// Number of unread emails.
    pub unread_emails: i64,
    /// Number of events in the next 7 days.
    pub upcoming_events: i64,
    /// Number of active projects.
    pub active_projects: i64,
    /// Top tasks by urgency score.
    pub high_urgency_tasks: Vec<HighUrgencyTask>,
}

/// A task with high urgency for dashboard display.
#[derive(Debug, Clone, serde::Serialize)]
pub struct HighUrgencyTask {
    /// Task ID as string.
    pub id: String,
    /// Task description.
    pub description: String,
    /// Calculated urgency score.
    pub urgency: f64,
    /// Task status.
    pub status: String,
    /// Due date if set, formatted as ISO string.
    pub due: Option<String>,
}

/// Repository for dashboard statistics.
#[async_trait]
pub trait StatsRepository: Send + Sync {
    /// Computes aggregated dashboard statistics for a user.
    ///
    /// Calendar-day windows (`today_start`, `tomorrow_start`, `week_end`) are
    /// passed in as UTC instants derived from the user's *local* day, so "due
    /// today/this week" respect the user's timezone rather than UTC midnights.
    /// `now` is the reference instant for overdue/upcoming comparisons.
    async fn get_dashboard_stats(
        &self,
        user_id: UserId,
        now: DateTime<Utc>,
        today_start: DateTime<Utc>,
        tomorrow_start: DateTime<Utc>,
        week_end: DateTime<Utc>,
    ) -> Result<DashboardStats>;
}