import SwiftUI

struct HistoryRow: Identifiable {
    let entry: Entry
    let task: String
    let person: String
    let partner: String
    var id: String { entry.id }
    var date: String { entry.date }
    var note: String { entry.note }
}

struct HistoryView: View {
    @EnvironmentObject var store: Store
    @EnvironmentObject var ui: UIState
    @State private var query = ""
    @State private var taskFilter = ""
    @State private var selection = Set<String>()
    @State private var sortOrder = [KeyPathComparator(\HistoryRow.date, order: .reverse)]

    private var rows: [HistoryRow] {
        let q = query.lowercased()
        return store.db.entries
            .filter { taskFilter.isEmpty || $0.task == taskFilter }
            .map { e in
                HistoryRow(entry: e, task: store.task(e.task)?.name ?? e.task, person: store.name(e.person),
                           partner: e.partner.isEmpty ? "" : store.name(e.partner))
            }
            .filter { q.isEmpty || "\($0.task) \($0.person) \($0.partner) \($0.note)".lowercased().contains(q) }
            .sorted(using: sortOrder)
    }

    var body: some View {
        let rows = rows
        VStack(spacing: 0) {
            HStack(spacing: 12) {
                TextField("Suchen (Name, Notiz …)", text: $query)
                    .textFieldStyle(.roundedBorder)
                    .frame(width: 260)
                Picker("Aufgabe", selection: $taskFilter) {
                    Text("Alle Aufgaben").tag("")
                    ForEach(store.db.tasks.filter { !$0.partnerColumn }) { Text($0.name).tag($0.id) }
                }
                .frame(width: 280)
                Text("\(rows.count) Einträge").foregroundStyle(Theme.muted)
                Spacer()
                Button("Bearbeiten") { edit(selection.first) }.disabled(selection.count != 1)
                Button("Löschen", role: .destructive) { delete(selection) }.disabled(selection.isEmpty)
            }
            .padding(16)

            Table(rows, selection: $selection, sortOrder: $sortOrder) {
                TableColumn("Datum", value: \.date) { Text(Day.display($0.date)).monospacedDigit() }.width(90)
                TableColumn("Aufgabe", value: \.task).width(min: 160, ideal: 220)
                TableColumn("Person", value: \.person).width(min: 140, ideal: 200)
                TableColumn("Partner", value: \.partner).width(min: 120, ideal: 180)
                TableColumn("Thema / Notiz", value: \.note) { Text($0.note).foregroundStyle(Theme.muted) }
            }
            .contextMenu(forSelectionType: String.self) { ids in
                if ids.count == 1 { Button("Bearbeiten") { edit(ids.first) } }
                Button("Löschen", role: .destructive) { delete(ids) }
            } primaryAction: { ids in edit(ids.first) }
            .onDeleteCommand { delete(selection) }
            .overlay {
                if store.db.entries.isEmpty {
                    Text("Noch keine Einträge. Mit ⌘N oder einem Klick in die Übersicht geht's los.")
                        .foregroundStyle(Theme.muted)
                }
            }
        }
    }

    private func edit(_ id: String?) {
        guard let id, let e = store.db.entries.first(where: { $0.id == id }) else { return }
        ui.draft = e
    }

    private func delete(_ ids: Set<String>) {
        guard !ids.isEmpty else { return }
        let alert = NSAlert()
        alert.messageText = ids.count == 1 ? "Eintrag löschen?" : "\(ids.count) Einträge löschen?"
        alert.informativeText = "Das lässt sich nicht rückgängig machen."
        alert.addButton(withTitle: "Löschen").hasDestructiveAction = true
        alert.addButton(withTitle: "Abbrechen")
        guard alert.runModal() == .alertFirstButtonReturn else { return }
        ids.forEach(store.delete(entry:))
        selection.subtract(ids)
    }
}