import AppKit
import SwiftUI

/// 菜单栏图标：每项独立时一个指标一个图标，点击弹出该项详情；合并时只有一个图标，点击打开主窗口
@MainActor
final class MenuBarController: NSObject {
    private let model: AppModel
    private var items: [(key: MenuBarItem?, statusItem: NSStatusItem)] = []
    private var panels: [MenuBarItem: StatusPanel] = [:]
    private var layoutSignature: [MenuBarItem?] = []

    /// 开发调试：启动后展开并固定某个弹窗
    var pinsNextPopover = false

    init(model: AppModel) {
        self.model = model
        super.init()
    }

    // MARK: 图标

    /// 布局或显示项目变化时重建；否则只重绘图片
    func update() {
        let settings = model.settings
        let enabled = settings.orderedMenuBarItems
        // 没有任何项目时保留一个图标，确保仍能打开主窗口
        let signature: [MenuBarItem?] = settings.menuBarLayout == .separate && !enabled.isEmpty ? enabled : [nil]
        if signature != layoutSignature {
            rebuild(signature)
        }
        refreshImages()
    }

    private func rebuild(_ signature: [MenuBarItem?]) {
        dismissPopovers()
        for entry in items { NSStatusBar.system.removeStatusItem(entry.statusItem) }
        items = []
        panels = panels.filter { key, _ in signature.contains(key) }
        layoutSignature = signature

        // 新建的状态栏图标出现在已有图标左侧，倒序创建才能保持从左到右的顺序
        for key in signature.reversed() {
            let statusItem = NSStatusBar.system.statusItem(withLength: NSStatusItem.variableLength)
            if let button = statusItem.button {
                button.target = self
                button.action = #selector(statusItemClicked(_:))
                button.sendAction(on: [.leftMouseUp, .rightMouseUp])
                button.imagePosition = .imageOnly
            }
            items.insert((key, statusItem), at: 0)
        }
    }

    func refreshImages() {
        let settings = model.settings
        let reading = MenuBarReading(model: model)
        for (index, entry) in items.enumerated() {
            let itemsToDraw = entry.key.map { [$0] } ?? settings.orderedMenuBarItems
            var entryReading = reading
            // 防休眠标记只画在最左侧的图标里
            entryReading.keepAwake = reading.keepAwake && index == 0
            entry.statusItem.button?.image = MenuBarRenderer.image(reading: entryReading,
                                                                  items: itemsToDraw,
                                                                  style: { settings.style(for: $0) },
                                                                  networkStyle: settings.networkStyle,
                                                                  colorizeHighLoad: settings.colorizeHighLoad,
                                                                  fahrenheit: settings.useFahrenheit)
            entry.statusItem.button?.toolTip = reading.tooltip(items: itemsToDraw, fahrenheit: settings.useFahrenheit)
        }
    }

    // MARK: 点击

    @objc private func statusItemClicked(_ sender: NSStatusBarButton) {
        guard let entry = items.first(where: { $0.statusItem.button === sender }) else { return }
        if NSApp.currentEvent?.type == .rightMouseUp {
            showContextMenu(for: entry.statusItem)
        } else if let key = entry.key {
            togglePopover(key, button: sender)
        } else {
            model.openMainWindow(nil)
        }
    }

    func togglePopover(_ item: MenuBarItem, button: NSStatusBarButton? = nil) {
        guard let button = button ?? items.first(where: { $0.key == item })?.statusItem.button,
              let window = button.window else { return }
        for (key, panel) in panels where key != item { panel.dismiss() }
        let frame = window.convertToScreen(button.convert(button.bounds, to: nil))
        let panel = self.panel(for: item)
        panel.toggle(below: frame, on: window.screen)
        if pinsNextPopover, panel.isVisible {
            panel.isPinned = true
            pinsNextPopover = false
        }
    }

    func dismissPopovers() {
        for panel in panels.values { panel.dismiss() }
    }

    func refreshPopoverHeight() {
        for panel in panels.values { panel.refreshHeight() }
    }

    private func panel(for item: MenuBarItem) -> StatusPanel {
        if let panel = panels[item] { return panel }
        let model = self.model
        let panel = StatusPanel(width: DS.Size.popoverWidth,
                                content: { PopoverRootView(item: item).environment(model) },
                                measuring: { PopoverRootView(item: item).environment(model).environment(\.isSnapshot, true) })
        panel.onVisibilityChange = { [weak self] visible in
            guard let self else { return }
            if visible {
                self.model.openPopover = item
                self.model.helper.refreshStatus()
            } else if self.model.openPopover == item {
                self.model.openPopover = nil
            }
            self.items.first { $0.key == item }?.statusItem.button?.highlight(visible)
        }
        panels[item] = panel
        return panel
    }

    private func showContextMenu(for statusItem: NSStatusItem) {
        dismissPopovers()
        let menu = NSMenu()
        menu.addItem(withTitle: "打开 OpenStats", action: #selector(openMainWindow), keyEquivalent: "").target = self
        menu.addItem(withTitle: "设置…", action: #selector(openSettings), keyEquivalent: ",").target = self
        menu.addItem(.separator())
        menu.addItem(withTitle: "退出 OpenStats", action: #selector(NSApplication.terminate(_:)), keyEquivalent: "q")
        statusItem.menu = menu
        statusItem.button?.performClick(nil)
        statusItem.menu = nil
    }

    @objc private func openMainWindow() { model.openMainWindow(nil) }
    @objc private func openSettings() { model.openSettings() }
}