import SwiftUI
import LabWiseKit

private let isoDateFormatter: ISO8601DateFormatter = {
    let f = ISO8601DateFormatter()
    f.formatOptions = [.withFullDate]
    return f
}()

private let isoTimestampFormatter: ISO8601DateFormatter = {
    let f = ISO8601DateFormatter()
    f.formatOptions = [.withInternetDateTime, .withFractionalSeconds]
    return f
}()

private let displayDateFormatter: DateFormatter = {
    let f = DateFormatter()
    f.dateStyle = .medium
    f.timeStyle = .none
    return f
}()

private let displayTimestampFormatter: DateFormatter = {
    let f = DateFormatter()
    f.dateStyle = .medium
    f.timeStyle = .short
    return f
}()

private func formatDate(_ iso: String?) -> String {
    guard let iso else { return "" }
    if let date = isoDateFormatter.date(from: iso) {
        return displayDateFormatter.string(from: date)
    }
    // Fallback: try full timestamp (e.g. "2025-03-01T00:00:00.000Z")
    if let date = isoTimestampFormatter.date(from: iso) {
        return displayDateFormatter.string(from: date)
    }
    return iso
}

private func formatTimestamp(_ iso: String?) -> String {
    guard let iso else { return "" }
    if let date = isoTimestampFormatter.date(from: iso) {
        return displayTimestampFormatter.string(from: date)
    }
    return iso
}

struct ChemicalDetailView: View {
    @State private var chemical: Chemical
    @State private var showEdit = false

    init(chemical: Chemical) {
        self._chemical = State(initialValue: chemical)
    }

    var body: some View {
        Form {
            Section("Identity") {
                LabeledContent("Name", value: chemical.chemicalName)
                LabeledContent("CAS Number", value: chemical.casNumber)
                if let formula = chemical.chemicalFormula {
                    LabeledContent("Formula", value: formula)
                }
                if let mw = chemical.molecularWeight {
                    LabeledContent("Molecular Weight", value: mw)
                }
                LabeledContent("Physical State", value: chemical.physicalState.capitalized)
                if let conc = chemical.concentration {
                    LabeledContent("Concentration", value: conc)
                }
            }

            Section("Storage") {
                LabeledContent("Location", value: chemical.storageLocation)
                LabeledContent("Device", value: chemical.storageDevice)
                LabeledContent("Building", value: chemical.bldgCode)
                LabeledContent("Lab", value: chemical.lab)
                LabeledContent("Containers", value: chemical.numberOfContainers)
                LabeledContent("Amount / Container", value: "\(chemical.amountPerContainer) \(chemical.unitOfMeasure)")
                if let pct = chemical.percentageFull {
                    LabeledContent("% Full") {
                        HStack(spacing: 8) {
                            PercentageBar(value: pct / 100)
                                .frame(width: 80, height: 6)
                            Text("\(Int(pct))%")
                                .font(.callout)
                        }
                    }
                }
            }

            Section("Vendor") {
                LabeledContent("PI", value: chemical.piFirstName)
                if let vendor = chemical.vendor {
                    LabeledContent("Vendor", value: vendor)
                }
                if let catalog = chemical.catalogNumber {
                    LabeledContent("Catalog #", value: catalog)
                }
                if let lot = chemical.lotNumber {
                    LabeledContent("Lot #", value: lot)
                }
                if let exp = chemical.expirationDate, !exp.isEmpty {
                    LabeledContent("Expiration", value: formatDate(exp))
                }
                if let barcode = chemical.barcode {
                    LabeledContent("Barcode", value: barcode)
                }
                if let contact = chemical.contact {
                    LabeledContent("Contact", value: contact)
                }
            }

            if let comments = chemical.comments, !comments.isEmpty {
                Section("Comments") {
                    Text(comments)
                        .font(.body)
                }
            }

            Section("Record") {
                if let created = chemical.createdAt {
                    LabeledContent("Created", value: formatTimestamp(created))
                }
                if let updated = chemical.updatedAt {
                    LabeledContent("Updated", value: formatTimestamp(updated))
                }
            }
        }
        .navigationTitle(chemical.chemicalName)
        .navigationBarTitleDisplayMode(.inline)
        .toolbar {
            ToolbarItem(placement: .topBarTrailing) {
                Button {
                    showEdit = true
                } label: {
                    Image(systemName: "pencil")
                }
            }
        }
        .sheet(isPresented: $showEdit) {
            AddChemicalView(editing: chemical) { saved in
                showEdit = false
                if saved {
                    Task { await reloadChemical() }
                }
            }
        }
    }

    // Reload from server so the detail view reflects the saved changes.
    private func reloadChemical() async {
        let updated = try? await ChemicalsClient().list()
        if let match = updated?.first(where: { $0.id == chemical.id }) {
            chemical = match
        }
    }
}