//
//  Tab.swift
//  Prisme
//
//  Author: Simon-Pierre Boucher <contact@spboucher.ai>
//

import Foundation
import Observation

/// What Prisme understood of the current page, deterministically and
/// instantly — the visible proof that the browser read the page. The
/// digest enriches it when the local model delivers.
struct PageInsight: Equatable, Sendable {
    let url: URL
    let approxWords: Int
    let sectionCount: Int

    var readingMinutes: Int { max(1, approxWords / 200) }
}

/// A browsing tab. Holds no `WKWebView` of its own — web views live in the
/// pool (CLAUDE.md §8) and are attached only while the tab is on screen.
/// Page state survives detachment through `interactionState`, which
/// preserves the back/forward history and scroll position.
@MainActor
@Observable
final class Tab: Identifiable {
    let id = UUID()
    let containerID: IdentityContainer.ID

    /// URL to load when the tab first gets a web view. Nil = start page.
    var initialURL: URL?

    /// Live navigation state and commands, bridged from the engine.
    let page = WebPageProxy()

    /// Opaque WebKit session state, captured when the tab goes off screen.
    @ObservationIgnored var interactionState: Any?

    /// Set after each settled load; drives the understanding strip.
    var insight: PageInsight?
    /// The user dismissed the strip for the current page.
    var insightDismissed = false

    let createdAt = Date()
    var lastActivatedAt = Date()

    init(initialURL: URL?, containerID: IdentityContainer.ID) {
        self.initialURL = initialURL
        self.containerID = containerID
    }

    var displayTitle: String {
        if !page.title.isEmpty { return page.title }
        if let host = (page.url ?? initialURL)?.host() { return host }
        return "Nouvel onglet"
    }

    /// True while the tab has nothing to render — show the start page.
    var isBlank: Bool {
        page.url == nil && initialURL == nil && interactionState == nil
    }
}