//
//  BrowserWindowView.swift
//  Zyquo Atlas
//
//  Author: Simon-Pierre Boucher
//  Mail: contact@spboucher.ai
//
//  The browser window root. Composes the chrome — tab strip (top-horizontal OR
//  left-vertical per the live layout), optional bookmarks bar, toolbar, find
//  bar, web content, and the AI sidebar — themed live by ThemeEngine and driven
//  by a per-window WindowState that the app commands target. Hosts the history,
//  bookmarks-manager, downloads, and customization panels.
//

import SwiftUI

struct BrowserWindowView: View {
    @EnvironmentObject private var env: AppEnvironment
    @EnvironmentObject private var themeEngine: ThemeEngine
    @StateObject private var tabManager: TabManager
    @StateObject private var windowState = WindowState()

    private let profile: Profile

    init(profile: Profile = .defaultProfile) {
        self.profile = profile
        _tabManager = StateObject(wrappedValue: TabManager(profile: profile))
    }

    private var theme: AtlasTheme { themeEngine.theme }
    private var layout: LayoutSettings { themeEngine.layout }

    var body: some View {
        Group {
            if layout.tabPosition == .left {
                HStack(spacing: 0) {
                    VerticalTabBarView(tabManager: tabManager, onNewTab: { tabManager.newTab() })
                    mainColumn
                }
            } else {
                VStack(spacing: 0) {
                    TabBarView(tabManager: tabManager)
                    mainColumn
                }
            }
        }
        .background(theme.backgroundColor)
        .frame(minWidth: 900, minHeight: 600)
        .animation(.easeInOut(duration: 0.15), value: windowState.showAISidebar)
        .animation(.easeInOut(duration: 0.18), value: layout.tabPosition)
        .environmentObject(windowState)
        .focusedSceneValue(\.windowState, windowState)
        .onAppear {
            windowState.tabManager = tabManager
            windowState.env = env
            if tabManager.history == nil {
                tabManager.history = profile.isPrivate ? nil : env.history
                tabManager.restoreSessionOrOpenHome()
            }
        }
        .sheet(isPresented: $windowState.showCustomize) {
            CustomizationView().environmentObject(themeEngine)
        }
        .sheet(isPresented: $windowState.showHistory) {
            HistoryView(onOpen: { tabManager.newTab(url: URL(string: $0)) })
                .environmentObject(env).environmentObject(themeEngine)
        }
        .sheet(isPresented: $windowState.showBookmarksManager) {
            BookmarksManagerView(onOpen: { tabManager.newTab(url: URL(string: $0)) })
                .environmentObject(env).environmentObject(themeEngine)
        }
    }

    // MARK: - Main column (bookmarks bar + toolbar + content + AI sidebar)

    @ViewBuilder
    private var mainColumn: some View {
        if let tab = tabManager.activeTab {
            VStack(spacing: 0) {
                ToolbarView(
                    tab: tab,
                    isAISidebarOpen: windowState.showAISidebar,
                    onSubmit: { tabManager.loadInActiveTab($0) },
                    onNewTab: { tabManager.newTab() },
                    onToggleAI: { windowState.showAISidebar.toggle() },
                    onCustomize: { windowState.showCustomize = true },
                    downloadCount: tabManager.downloads.items.filter { $0.state == .inProgress }.count,
                    onToggleDownloads: { windowState.showDownloads.toggle() }
                )
                if layout.showBookmarksBar && !profile.isPrivate {
                    BookmarksBarView(onOpen: { tabManager.loadInActiveTab($0) })
                }
                if windowState.showFindBar {
                    FindBarView(tab: tab, onClose: { windowState.showFindBar = false })
                }
                HStack(spacing: 0) {
                    TabContentView(
                        tab: tab,
                        onNavigate: { tabManager.loadInActiveTab($0) },
                        onAsk: { windowState.showAISidebar = true }
                    )
                    if windowState.showAISidebar {
                        AISidebarView(tab: tab, ai: tab.ai, tabManager: tabManager)
                            .transition(.move(edge: .trailing))
                    }
                }
            }
            .overlay(alignment: .topTrailing) {
                if windowState.showDownloads {
                    DownloadsPopover(downloads: tabManager.downloads,
                                     onClose: { windowState.showDownloads = false })
                        .padding(.top, 4).padding(.trailing, 8)
                }
            }
        } else {
            Spacer()
        }
    }

}

/// The active tab's content region. Observes the tab so it switches reactively
/// between the start page (blank/home), reader mode, and live web content as the
/// URL changes — and overlays the selection toolbar on web pages.
private struct TabContentView: View {
    @ObservedObject var tab: Tab
    let onNavigate: (String) -> Void
    let onAsk: () -> Void
    @EnvironmentObject private var windowState: WindowState

    var body: some View {
        if tab.url == nil || tab.url == TabManager.homeURL {
            StartPageView(onNavigate: onNavigate, onAsk: onAsk)
        } else if windowState.showReader {
            ReaderView(tab: tab)
        } else {
            WebContentArea(tab: tab)
                .overlay { SelectionToolbar(tab: tab) }
        }
    }
}

/// Hosts the active tab's web view. Keyed by tab id so SwiftUI re-mounts the
/// correct WKWebView on a tab switch while background tabs keep theirs alive.
private struct WebContentArea: View {
    @ObservedObject var tab: Tab

    var body: some View {
        WebView(tab: tab)
            .id(tab.id)
    }
}