//
//  PlaceProvider.swift
//  Focale
//
//  Author: Simon-Pierre Boucher
//  Contact: contact@spboucher.ai
//
//  Turns the device location into a coarse PlaceRef (locality, never raw
//  coordinates — CLAUDE.md §4). Everything stays on-device; CLGeocoder
//  lookups are throttled and cached.
//

import CoreLocation
import Foundation
import Observation

@MainActor
@Observable
final class PlaceProvider: NSObject, CLLocationManagerDelegate {

    private(set) var currentPlace: PlaceRef?

    private let manager = CLLocationManager()
    private let geocoder = CLGeocoder()
    private var lastGeocodedLocation: CLLocation?

    override init() {
        super.init()
        manager.delegate = self
        manager.desiredAccuracy = kCLLocationAccuracyHundredMeters
    }

    func startIfAuthorized() {
        switch manager.authorizationStatus {
        case .notDetermined:
            manager.requestWhenInUseAuthorization()
        case .authorizedWhenInUse, .authorizedAlways:
            manager.startUpdatingLocation()
        default:
            break
        }
    }

    func stop() {
        manager.stopUpdatingLocation()
    }

    nonisolated func locationManagerDidChangeAuthorization(_ manager: CLLocationManager) {
        Task { @MainActor in self.startIfAuthorized() }
    }

    nonisolated func locationManager(
        _ manager: CLLocationManager,
        didUpdateLocations locations: [CLLocation]
    ) {
        guard let location = locations.last else { return }
        Task { @MainActor in self.geocodeIfNeeded(location) }
    }

    private func geocodeIfNeeded(_ location: CLLocation) {
        // Re-geocode only after moving ~500 m; place names don't change faster.
        if let previous = lastGeocodedLocation,
           location.distance(from: previous) < 500 { return }
        lastGeocodedLocation = location

        Task {
            guard let placemark = try? await geocoder.reverseGeocodeLocation(location).first
            else { return }
            currentPlace = PlaceRef(
                name: placemark.areasOfInterest?.first,
                locality: placemark.locality,
                countryCode: placemark.isoCountryCode
            )
        }
    }
}