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

import Foundation
import Observation

/// Ordered collection of open tabs plus the active selection.
/// Grouping by intention (P0) will layer on top of this later — the store
/// itself stays a dumb, predictable list.
@MainActor
@Observable
final class TabStore {
    private(set) var tabs: [Tab] = []
    var activeTabID: Tab.ID?

    var activeTab: Tab? {
        guard let id = activeTabID else { return nil }
        return tabs.first { $0.id == id }
    }

    func tabs(in containerID: IdentityContainer.ID) -> [Tab] {
        tabs.filter { $0.containerID == containerID }
    }

    func mostRecentTab(in containerID: IdentityContainer.ID) -> Tab? {
        tabs(in: containerID).max { $0.lastActivatedAt < $1.lastActivatedAt }
    }

    @discardableResult
    func open(_ url: URL?, in containerID: IdentityContainer.ID, activate: Bool = true) -> Tab {
        let tab = Tab(initialURL: url, containerID: containerID)
        tabs.append(tab)
        if activate {
            self.activate(tab)
        }
        return tab
    }

    func activate(_ tab: Tab) {
        tab.lastActivatedAt = Date()
        activeTabID = tab.id
    }

    func close(_ tab: Tab) {
        guard let index = tabs.firstIndex(where: { $0.id == tab.id }) else { return }
        tabs.remove(at: index)
        guard activeTabID == tab.id else { return }
        // Prefer a neighbour from the same container, else none.
        let siblings = tabs(in: tab.containerID)
        activeTabID = siblings.last?.id
    }
}