import SwiftUI
import LabWiseKit

struct SpreadsheetView: View {
    let chemicals: [Chemical]
    let onDismiss: () -> Void

    private struct ColumnDef {
        let label: String
        let width: CGFloat
        let value: (Chemical) -> String
    }

    private static let columnDefs: [ColumnDef] = [
        ColumnDef(label: "PI First Name",       width: 130) { $0.piFirstName },
        ColumnDef(label: "Physical State",       width: 120) { $0.physicalState },
        ColumnDef(label: "Chemical Name",        width: 180) { $0.chemicalName },
        ColumnDef(label: "Bldg Code",            width: 100) { $0.bldgCode },
        ColumnDef(label: "LAB",                  width: 80)  { $0.lab },
        ColumnDef(label: "Storage Location",     width: 145) { $0.storageLocation },
        ColumnDef(label: "Storage Device",       width: 140) { $0.storageDevice },
        ColumnDef(label: "# of Containers",      width: 120) { $0.numberOfContainers },
        ColumnDef(label: "Amount / Container",   width: 150) { $0.amountPerContainer },
        ColumnDef(label: "Unit of Measure",      width: 130) { $0.unitOfMeasure },
        ColumnDef(label: "CAS #",                width: 115) { $0.casNumber },
        ColumnDef(label: "Chemical Formula",     width: 140) { $0.chemicalFormula ?? "" },
        ColumnDef(label: "Molecular Weight",     width: 130) { $0.molecularWeight ?? "" },
        ColumnDef(label: "Vendor",               width: 130) { $0.vendor ?? "" },
        ColumnDef(label: "Catalog #",            width: 120) { $0.catalogNumber ?? "" },
        ColumnDef(label: "Lot Number",           width: 120) { $0.lotNumber ?? "" },
        ColumnDef(label: "Concentration",        width: 120) { $0.concentration ?? "" },
        ColumnDef(label: "Expiration Date",      width: 130) { $0.expirationDate ?? "" },
        ColumnDef(label: "Contact",              width: 130) { $0.contact ?? "" },
        ColumnDef(label: "Barcode",              width: 130) { $0.barcode ?? "" },
        ColumnDef(label: "Comments",             width: 180) { $0.comments ?? "" },
        ColumnDef(label: "% Full",               width: 80) { c in
            c.percentageFull.map { String(format: "%.0f%%", $0) } ?? ""
        },
        ColumnDef(label: "Date Entered",         width: 130) { c in
            c.createdAt.map { String($0.prefix(10)) } ?? ""
        },
        ColumnDef(label: "Last Changed",         width: 130) { c in
            c.updatedAt.map { String($0.prefix(10)) } ?? ""
        },
    ]

    private static let headerHeight: CGFloat = 48

    var body: some View {
        VStack(spacing: 0) {
            // Top bar
            HStack(spacing: 4) {
                Button {
                    restorePortrait()
                    onDismiss()
                } label: {
                    Image(systemName: "xmark.circle.fill")
                        .font(.title2)
                        .foregroundStyle(.secondary)
                }
                .padding(.leading, 12)

                Text("Inventory Spreadsheet")
                    .font(.headline)
                    .padding(.leading, 4)

                Spacer()

                Text("\(chemicals.count) item\(chemicals.count == 1 ? "" : "s")")
                    .font(.subheadline)
                    .foregroundStyle(.secondary)
                    .padding(.trailing, 16)
            }
            .frame(height: 50)
            .background(Color(.systemBackground))

            Divider()

            // Table
            GeometryReader { proxy in
                ScrollView(.horizontal, showsIndicators: true) {
                    VStack(alignment: .leading, spacing: 0) {
                        // Sticky header row
                        HStack(spacing: 0) {
                            ForEach(Array(Self.columnDefs.enumerated()), id: \.offset) { i, col in
                                Text(col.label)
                                    .font(.caption.weight(.semibold))
                                    .foregroundStyle(.white)
                                    .lineLimit(2)
                                    .multilineTextAlignment(.center)
                                    .frame(width: col.width, height: Self.headerHeight)
                                    .padding(.horizontal, 4)

                                if i < Self.columnDefs.count - 1 {
                                    Rectangle()
                                        .fill(Color.white.opacity(0.35))
                                        .frame(width: 1, height: Self.headerHeight)
                                }
                            }
                        }
                        .background(Color.accentColor)

                        Divider()

                        // Scrollable data rows
                        ScrollView(.vertical, showsIndicators: true) {
                            LazyVStack(spacing: 0) {
                                ForEach(Array(chemicals.enumerated()), id: \.element.id) { idx, chemical in
                                    HStack(spacing: 0) {
                                        ForEach(Array(Self.columnDefs.enumerated()), id: \.offset) { i, col in
                                            Text(col.value(chemical))
                                                .font(.caption)
                                                .lineLimit(1)
                                                .frame(width: col.width, alignment: .leading)
                                                .padding(.vertical, 7)
                                                .padding(.horizontal, 6)
                                                .background(idx % 2 == 0
                                                    ? Color(.systemBackground)
                                                    : Color(.systemGray6))

                                            if i < Self.columnDefs.count - 1 {
                                                Rectangle()
                                                    .fill(Color(.separator))
                                                    .frame(width: 0.5)
                                                    .frame(height: 30)
                                            }
                                        }
                                    }
                                    Divider()
                                }
                            }
                        }
                        // Subtract header height and the 1-pt divider
                        .frame(height: proxy.size.height - Self.headerHeight - 1)
                    }
                }
            }
        }
        .onAppear {
            // Slight delay so the full-screen cover animation finishes before rotating
            DispatchQueue.main.asyncAfter(deadline: .now() + 0.15) {
                setLandscape()
            }
        }
        .onDisappear {
            // Safety net in case something else dismisses this view
            restorePortrait()
        }
    }

    // MARK: - Orientation helpers

    private func setLandscape() {
        AppDelegate.orientationLock = .landscape
        guard let scene = UIApplication.shared.connectedScenes.first as? UIWindowScene else { return }
        scene.requestGeometryUpdate(.iOS(interfaceOrientations: .landscape))
    }

    private func restorePortrait() {
        AppDelegate.orientationLock = .allButUpsideDown
        guard let scene = UIApplication.shared.connectedScenes.first as? UIWindowScene else { return }
        scene.requestGeometryUpdate(.iOS(interfaceOrientations: .portrait))
    }
}