import SwiftUI

struct HistoryView: View {
    @EnvironmentObject var store: ConnectionStore

    var body: some View {
        ZStack {
            AppTheme.background.ignoresSafeArea()

            if store.historyEntries.isEmpty {
                emptyState
            } else {
                List {
                    ForEach(store.historyEntries) { entry in
                        HistoryRowView(entry: entry)
                            .listRowSeparator(.hidden)
                            .listRowInsets(EdgeInsets())
                            .listRowBackground(AppTheme.background)
                    }
                    .onDelete { store.removeHistoryEntries(at: $0) }
                }
                .listStyle(.plain)
                .scrollContentBackground(.hidden)
            }
        }
        .navigationTitle("History")
        .toolbar {
            if !store.historyEntries.isEmpty {
                ToolbarItem(placement: .navigationBarTrailing) {
                    Button("Clear") { store.clearHistory() }
                        .font(AppTheme.caption())
                        .foregroundStyle(AppTheme.inkTertiary)
                }
            }
        }
    }

    private var emptyState: some View {
        VStack(spacing: 14) {
            Image(systemName: "clock.arrow.circlepath")
                .font(.system(size: 32, weight: .light))
                .foregroundStyle(AppTheme.inkQuaternary)
            VStack(spacing: 5) {
                Text("No backups yet")
                    .font(.system(size: 15, weight: .medium))
                    .foregroundStyle(AppTheme.inkSecondary)
                Text("Your backup history will appear here")
                    .font(AppTheme.caption())
                    .foregroundStyle(AppTheme.inkTertiary)
            }
        }
    }
}

// MARK: — Row

struct HistoryRowView: View {
    let entry: BackupHistoryEntry

    private var hasErrors: Bool { entry.failedCount > 0 }
    private var statusColor: Color { hasErrors ? AppTheme.destructive : AppTheme.positive }

    var body: some View {
        VStack(spacing: 0) {
            HStack(alignment: .top, spacing: 14) {
                // Status indicator
                Circle()
                    .fill(statusColor)
                    .frame(width: 6, height: 6)
                    .padding(.top, 6)

                // Content
                VStack(alignment: .leading, spacing: 5) {
                    // Date + badges
                    HStack(alignment: .firstTextBaseline, spacing: 6) {
                        Text(entry.date, format: .dateTime.month(.abbreviated).day().year())
                            .font(.system(size: 14, weight: .medium))
                            .foregroundStyle(AppTheme.ink)

                        Text(entry.date, format: .dateTime.hour().minute())
                            .font(.system(size: 13, weight: .regular))
                            .foregroundStyle(AppTheme.inkTertiary)

                        Spacer()

                        if entry.triggeredByLAN {
                            Text("AUTO")
                                .font(.system(size: 9, weight: .semibold))
                                .foregroundStyle(AppTheme.inkSecondary)
                                .padding(.horizontal, 5)
                                .padding(.vertical, 2)
                                .overlay(
                                    RoundedRectangle(cornerRadius: 3, style: .continuous)
                                        .stroke(AppTheme.inkQuaternary, lineWidth: 0.75)
                                )
                        }
                    }

                    // Stat line
                    statLine

                    // Secondary info: host · duration · size
                    HStack(spacing: 6) {
                        Text(entry.nasHost)
                            .foregroundStyle(AppTheme.inkQuaternary)
                        midDot
                        Text(formatDuration(entry.durationSeconds))
                            .foregroundStyle(AppTheme.inkQuaternary)
                        if entry.totalBytes > 0 {
                            midDot
                            Text(formatBytes(entry.totalBytes))
                                .foregroundStyle(AppTheme.inkQuaternary)
                        }
                    }
                    .font(.system(size: 11, weight: .regular))
                }
            }
            .padding(.horizontal, 16)
            .padding(.vertical, 14)

            Rectangle()
                .fill(AppTheme.separator)
                .frame(height: 0.5)
                .padding(.leading, 36)
        }
    }

    @ViewBuilder
    private var statLine: some View {
        HStack(spacing: 6) {
            Text("\(entry.uploadedCount) uploaded")
                .foregroundStyle(AppTheme.inkSecondary)

            if entry.skippedCount > 0 {
                midDot
                Text("\(entry.skippedCount) skipped")
                    .foregroundStyle(AppTheme.inkTertiary)
            }

            if hasErrors {
                midDot
                Text("\(entry.failedCount) errors")
                    .foregroundStyle(AppTheme.destructive)
            }
        }
        .font(AppTheme.caption())
    }

    private var midDot: some View {
        Circle()
            .fill(AppTheme.inkQuaternary)
            .frame(width: 3, height: 3)
    }

    private func formatDuration(_ s: Double) -> String {
        let m = Int(s) / 60
        let sec = Int(s) % 60
        return m > 0 ? "\(m)m \(sec)s" : "\(sec)s"
    }

    private func formatBytes(_ bytes: Int64) -> String {
        let gb = Double(bytes) / 1_073_741_824
        if gb >= 1 { return String(format: "%.1f GB", gb) }
        let mb = Double(bytes) / 1_048_576
        if mb >= 1 { return String(format: "%.0f MB", mb) }
        return String(format: "%.0f KB", Double(bytes) / 1024)
    }
}