//
//  PlaceSearchSheet.swift
//  SportsTime
//
//  Focused place search sheet for custom itinerary items
//

import SwiftUI
import MapKit

/// A sheet for searching and selecting a place via MapKit
struct PlaceSearchSheet: View {
    @Environment(\.dismiss) private var dismiss
    @Environment(\.colorScheme) private var colorScheme

    /// Optional coordinate to bias search results toward (e.g., the trip stop for this day)
    var regionCoordinate: CLLocationCoordinate2D?

    /// Callback when a location is selected
    let onSelect: (MKMapItem) -> Void

    @State private var searchQuery = ""
    @State private var searchResults: [MKMapItem] = []
    @State private var isSearching = false
    @State private var searchError: String?
    @State private var debounceTask: Task<Void, Never>?
    @FocusState private var isSearchFocused: Bool

    var body: some View {
        NavigationStack {
            VStack(spacing: 0) {
                searchBar
                    .padding(Theme.Spacing.md)

                if isSearching {
                    loadingView
                } else if let error = searchError {
                    errorView(error)
                } else if searchResults.isEmpty && !searchQuery.isEmpty {
                    emptyResultsView
                } else if searchResults.isEmpty {
                    initialStateView
                } else {
                    resultsList
                }
            }
            .navigationTitle("Add Location")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .cancellationAction) {
                    Button("Cancel") {
                        dismiss()
                    }
                }
            }
        }
        .onAppear {
            isSearchFocused = true
        }
        .onDisappear {
            debounceTask?.cancel()
        }
    }

    // MARK: - Search Bar

    private var searchBar: some View {
        HStack(spacing: Theme.Spacing.sm) {
            Image(systemName: "magnifyingglass")
                .foregroundStyle(Theme.textMuted(colorScheme))
                .accessibilityHidden(true)

            TextField(searchPlaceholder, text: $searchQuery)
                .textFieldStyle(.plain)
                .focused($isSearchFocused)
                .onSubmit {
                    debounceTask?.cancel()
                    performSearch()
                }
                .onChange(of: searchQuery) {
                    debounceTask?.cancel()
                    let query = searchQuery
                    guard !query.trimmingCharacters(in: .whitespaces).isEmpty else {
                        searchResults = []
                        return
                    }
                    debounceTask = Task {
                        try? await Task.sleep(for: .milliseconds(500))
                        guard !Task.isCancelled else { return }
                        performSearch()
                    }
                }
                .accessibilityLabel("Search for places")
                .accessibilityHint(searchPlaceholder)

            if !searchQuery.isEmpty {
                Button {
                    searchQuery = ""
                    searchResults = []
                    searchError = nil
                    debounceTask?.cancel()
                } label: {
                    Image(systemName: "xmark.circle.fill")
                        .foregroundStyle(Theme.textMuted(colorScheme))
                }
                .minimumHitTarget()
                .accessibilityLabel("Clear search")
            }

            // Explicit search button
            if !searchQuery.trimmingCharacters(in: .whitespaces).isEmpty {
                Button {
                    debounceTask?.cancel()
                    performSearch()
                } label: {
                    Text("Search")
                        .font(.subheadline)
                        .fontWeight(.medium)
                        .foregroundStyle(.white)
                        .padding(.horizontal, 12)
                        .padding(.vertical, 6)
                        .background(Theme.warmOrange)
                        .clipShape(Capsule())
                }
                .accessibilityLabel("Search for \(searchQuery)")
            }
        }
        .padding(Theme.Spacing.sm)
        .background(Theme.cardBackground(colorScheme))
        .clipShape(RoundedRectangle(cornerRadius: Theme.CornerRadius.medium))
    }

    private let searchPlaceholder = "Search for a place..."

    // MARK: - Results List

    private var resultsList: some View {
        ScrollView {
            LazyVStack(spacing: Theme.Spacing.xs) {
                ForEach(searchResults, id: \.self) { place in
                    PlaceRow(place: place, colorScheme: colorScheme) {
                        onSelect(place)
                        dismiss()
                    }
                }
            }
            .padding(.horizontal, Theme.Spacing.md)
        }
    }

    // MARK: - Loading View

    private var loadingView: some View {
        VStack(spacing: Theme.Spacing.md) {
            Spacer()
            ProgressView()
                .scaleEffect(1.2)
            Text("Searching...")
                .font(.subheadline)
                .foregroundStyle(Theme.textSecondary(colorScheme))
            Spacer()
        }
        .frame(maxWidth: .infinity)
    }

    // MARK: - Empty Results View

    private var emptyResultsView: some View {
        VStack(spacing: Theme.Spacing.md) {
            Spacer()

            Image(systemName: "mappin.slash")
                .font(.largeTitle)
                .foregroundStyle(Theme.textMuted(colorScheme))
                .accessibilityHidden(true)

            Text("No places found")
                .font(.headline)
                .foregroundStyle(Theme.textPrimary(colorScheme))

            Text("Try a different search term")
                .font(.subheadline)
                .foregroundStyle(Theme.textSecondary(colorScheme))

            Button("Add without location") {
                dismiss()
            }
            .buttonStyle(.bordered)
            .tint(Theme.warmOrange)
            .padding(.top, Theme.Spacing.sm)
            .accessibilityHint("Returns to the add item form without a location")

            Spacer()
        }
        .frame(maxWidth: .infinity)
        .padding(Theme.Spacing.lg)
    }

    // MARK: - Initial State View

    private var initialStateView: some View {
        ScrollView {
            VStack(spacing: Theme.Spacing.xl) {
                // Illustration
                VStack(spacing: Theme.Spacing.sm) {
                    ZStack {
                        Circle()
                            .fill(Theme.warmOrange.opacity(0.1))
                            .frame(width: 80, height: 80)

                        Image(systemName: "map.fill")
                            .font(.system(size: 32))
                            .foregroundStyle(Theme.warmOrange)
                    }
                    .padding(.top, Theme.Spacing.xxl)

                    Text("Find a Place")
                        .font(.title3)
                        .fontWeight(.bold)
                        .foregroundStyle(Theme.textPrimary(colorScheme))

                    Text("Search for restaurants, attractions, hotels, and more")
                        .font(.subheadline)
                        .foregroundStyle(Theme.textSecondary(colorScheme))
                        .multilineTextAlignment(.center)
                        .padding(.horizontal, Theme.Spacing.lg)
                }

                // Suggestion chips
                VStack(alignment: .leading, spacing: Theme.Spacing.sm) {
                    Text("Try searching for")
                        .font(.caption)
                        .fontWeight(.semibold)
                        .foregroundStyle(Theme.textMuted(colorScheme))
                        .textCase(.uppercase)
                        .padding(.horizontal, Theme.Spacing.xs)

                    FlowLayout(spacing: Theme.Spacing.xs) {
                        ForEach(searchSuggestions, id: \.label) { suggestion in
                            Button {
                                searchQuery = suggestion.query
                                debounceTask?.cancel()
                                performSearch()
                            } label: {
                                Label(suggestion.label, systemImage: suggestion.icon)
                                    .font(.subheadline)
                                    .fontWeight(.medium)
                                    .foregroundStyle(Theme.textPrimary(colorScheme))
                                    .padding(.horizontal, Theme.Spacing.sm)
                                    .padding(.vertical, Theme.Spacing.xs)
                                    .background(Theme.cardBackground(colorScheme))
                                    .clipShape(Capsule())
                                    .overlay(
                                        Capsule()
                                            .strokeBorder(Theme.surfaceGlow(colorScheme), lineWidth: 1)
                                    )
                            }
                            .buttonStyle(.plain)
                        }
                    }
                }
                .padding(.horizontal, Theme.Spacing.md)
            }
        }
    }

    private struct SearchSuggestion {
        let label: String
        let query: String
        let icon: String
    }

    private var searchSuggestions: [SearchSuggestion] {
        [
            SearchSuggestion(label: "Restaurants", query: "restaurants", icon: "fork.knife"),
            SearchSuggestion(label: "Hotels", query: "hotels", icon: "bed.double.fill"),
            SearchSuggestion(label: "Coffee", query: "coffee shops", icon: "cup.and.saucer.fill"),
            SearchSuggestion(label: "Parking", query: "parking", icon: "car.fill"),
            SearchSuggestion(label: "Gas Stations", query: "gas stations", icon: "fuelpump.fill"),
            SearchSuggestion(label: "Attractions", query: "tourist attractions", icon: "star.fill"),
            SearchSuggestion(label: "Bars", query: "bars", icon: "wineglass.fill"),
            SearchSuggestion(label: "Parks", query: "parks", icon: "leaf.fill"),
        ]
    }

    // MARK: - Error View

    private func errorView(_ error: String) -> some View {
        VStack(spacing: Theme.Spacing.md) {
            Spacer()

            Image(systemName: "exclamationmark.triangle")
                .font(.largeTitle)
                .foregroundStyle(.orange)
                .accessibilityHidden(true)

            Text("Search unavailable")
                .font(.headline)
                .foregroundStyle(Theme.textPrimary(colorScheme))

            Text(error)
                .font(.subheadline)
                .foregroundStyle(Theme.textSecondary(colorScheme))
                .multilineTextAlignment(.center)

            HStack(spacing: Theme.Spacing.md) {
                Button("Add without location") {
                    dismiss()
                }
                .buttonStyle(.bordered)

                Button("Retry") {
                    performSearch()
                }
                .buttonStyle(.borderedProminent)
                .tint(Theme.warmOrange)
            }
            .padding(.top, Theme.Spacing.sm)

            Spacer()
        }
        .frame(maxWidth: .infinity)
        .padding(Theme.Spacing.lg)
    }

    // MARK: - Search

    private func performSearch() {
        let trimmedQuery = searchQuery.trimmingCharacters(in: .whitespaces)
        guard !trimmedQuery.isEmpty else { return }

        isSearching = true
        searchError = nil

        let request = MKLocalSearch.Request()
        request.naturalLanguageQuery = trimmedQuery

        // Bias results toward the trip stop's city if available
        if let coordinate = regionCoordinate {
            request.region = MKCoordinateRegion(
                center: coordinate,
                latitudinalMeters: 50_000,
                longitudinalMeters: 50_000
            )
        }

        let search = MKLocalSearch(request: request)
        search.start { response, error in
            isSearching = false

            if let error {
                searchError = error.localizedDescription
                return
            }

            if let response {
                searchResults = response.mapItems
            }
        }
    }
}

// MARK: - Flow Layout

private struct FlowLayout: Layout {
    var spacing: CGFloat = 8

    func sizeThatFits(proposal: ProposedViewSize, subviews: Subviews, cache: inout ()) -> CGSize {
        let result = arrangeSubviews(proposal: proposal, subviews: subviews)
        return result.size
    }

    func placeSubviews(in bounds: CGRect, proposal: ProposedViewSize, subviews: Subviews, cache: inout ()) {
        let result = arrangeSubviews(proposal: proposal, subviews: subviews)
        for (index, position) in result.positions.enumerated() {
            subviews[index].place(
                at: CGPoint(x: bounds.minX + position.x, y: bounds.minY + position.y),
                proposal: .unspecified
            )
        }
    }

    private func arrangeSubviews(proposal: ProposedViewSize, subviews: Subviews) -> (positions: [CGPoint], size: CGSize) {
        let maxWidth = proposal.width ?? .infinity
        var positions: [CGPoint] = []
        var currentX: CGFloat = 0
        var currentY: CGFloat = 0
        var lineHeight: CGFloat = 0

        for subview in subviews {
            let size = subview.sizeThatFits(.unspecified)

            if currentX + size.width > maxWidth && currentX > 0 {
                currentX = 0
                currentY += lineHeight + spacing
                lineHeight = 0
            }

            positions.append(CGPoint(x: currentX, y: currentY))
            lineHeight = max(lineHeight, size.height)
            currentX += size.width + spacing
        }

        return (positions, CGSize(width: maxWidth, height: currentY + lineHeight))
    }
}

// MARK: - Place Row

private struct PlaceRow: View {
    let place: MKMapItem
    let colorScheme: ColorScheme
    let onTap: () -> Void

    var body: some View {
        Button(action: onTap) {
            HStack(spacing: Theme.Spacing.sm) {
                Image(systemName: "mappin.circle.fill")
                    .font(.title2)
                    .foregroundStyle(Theme.warmOrange)

                VStack(alignment: .leading, spacing: Theme.Spacing.xxs) {
                    Text(place.name ?? "Unknown Place")
                        .font(.body)
                        .fontWeight(.medium)
                        .foregroundStyle(Theme.textPrimary(colorScheme))

                    if let address = formattedAddress {
                        Text(address)
                            .font(.caption)
                            .foregroundStyle(Theme.textSecondary(colorScheme))
                            .lineLimit(1)
                    }
                }

                Spacer()

                Image(systemName: "chevron.right")
                    .font(.caption)
                    .foregroundStyle(Theme.textMuted(colorScheme))
            }
            .padding(Theme.Spacing.sm)
            .background(Theme.cardBackground(colorScheme))
            .clipShape(RoundedRectangle(cornerRadius: Theme.CornerRadius.small))
        }
        .buttonStyle(.plain)
        .accessibilityLabel(place.name ?? "Unknown Place")
        .accessibilityHint(formattedAddress ?? "Tap to select this location")
    }

    private var formattedAddress: String? {
        let placemark = place.placemark
        var components: [String] = []

        if let thoroughfare = placemark.thoroughfare {
            components.append(thoroughfare)
        }
        if let locality = placemark.locality {
            components.append(locality)
        }
        if let administrativeArea = placemark.administrativeArea {
            components.append(administrativeArea)
        }

        return components.isEmpty ? nil : components.joined(separator: ", ")
    }
}

#Preview {
    PlaceSearchSheet { place in
        #if DEBUG
        print("Selected: \(place.name ?? "unknown")")
        #endif
    }
}