//! Phase 6 of the feature-complete roadmap: Margot soft-touch nudges.
//!
//! The nudge bus lives in the frontend (`nudgeBus.svelte.ts`) — it
//! owns trigger subscription, suppression rules, and the hourly cap.
//! This module is the thin Rust side that:
//!
//! - Guards delivery to the main window only (secondary windows like
//!   the task float can't fire notifications at the user — they're
//!   already beside the user's attention).
//! - Delegates to `tauri-plugin-notification` for cross-platform OS
//!   delivery. The plugin handles the macOS Notification Center /
//!   Linux org.freedesktop.Notifications / Windows toast plumbing.
//!
//! Permission handling happens on the JS side via the plugin's
//! `isPermissionGranted` / `requestPermission` API — before the first
//! `deliver_nudge` call, the nudge bus prompts the user. If denied,
//! subsequent calls return an error that the bus logs and swallows.
//!
//! No persistence for v1. Cooldown state is ephemeral; the roadmap's
//! nudge-audit table is deferred until a real need emerges.

use serde::Deserialize;
use tauri_plugin_notification::NotificationExt;

use crate::commands::security::ensure_main_window;

#[derive(Debug, Clone, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct DeliverNudgeInput {
    pub title: String,
    pub body: String,
}

/// Deliver a single OS notification. Does not apply suppression
/// logic — the frontend nudge bus is responsible for cadence and
/// cooldown, so this command is a blunt "push it now" primitive.
///
/// Returns an error if the notification plugin refuses the call
/// (typically because permission was denied by the user at the OS
/// level). The nudge bus logs and swallows these — nudges are
/// fire-and-forget and must never surface errors to the user.
#[tauri::command]
pub fn deliver_nudge(
    app: tauri::AppHandle,
    window: tauri::WebviewWindow,
    input: DeliverNudgeInput,
) -> Result<(), String> {
    ensure_main_window(&window)?;

    let title = input.title.trim();
    let body = input.body.trim();
    if title.is_empty() && body.is_empty() {
        // A blank nudge is worse than no nudge — stay quiet.
        return Ok(());
    }

    app.notification()
        .builder()
        .title(if title.is_empty() { "Lumotia" } else { title })
        .body(body)
        .show()
        .map_err(|e| format!("notification delivery failed: {e}"))
}