//
//  PollsListView.swift
//  SportsTime
//
//  View for listing user's polls
//

import SwiftUI

struct PollsListView: View {
    @Environment(\.colorScheme) private var colorScheme
    @State private var polls: [TripPoll] = []
    @State private var isLoading = false
    @State private var hasLoadedInitially = false
    @State private var errorMessage: String?
    @State private var showJoinPoll = false
    @State private var joinCode = ""
    @State private var pendingJoinCode: IdentifiableShareCode?

    var body: some View {
        Group {
            if isLoading && polls.isEmpty {
                ProgressView("Loading polls...")
            } else if polls.isEmpty {
                emptyState
            } else {
                pollsList
            }
        }
        .navigationTitle("Group Polls")
        .accessibilityIdentifier("polls.list")
        .toolbar {
            ToolbarItem(placement: .primaryAction) {
                Button {
                    showJoinPoll = true
                } label: {
                    Image(systemName: "link.badge.plus")
                        .accessibilityLabel("Join a poll")
                }
            }
        }
        .refreshable {
            await loadPolls()
        }
        .task {
            guard !hasLoadedInitially else { return }
            hasLoadedInitially = true
            await loadPolls()
        }
        .alert("Join Poll", isPresented: $showJoinPoll) {
            TextField("Enter code", text: $joinCode)
                .textInputAutocapitalization(.characters)
            Button("Join") {
                let normalizedCode = joinCode
                    .trimmingCharacters(in: .whitespacesAndNewlines)
                    .uppercased()

                guard normalizedCode.count == 6 else {
                    errorMessage = "Share code must be exactly 6 characters."
                    return
                }

                pendingJoinCode = IdentifiableShareCode(id: normalizedCode)
                joinCode = ""
            }
            Button("Cancel", role: .cancel) {
                joinCode = ""
            }
        } message: {
            Text("Enter the 6-character poll code")
        }
        .navigationDestination(item: $pendingJoinCode) { code in
            PollDetailView(shareCode: code.value)
        }
        .navigationDestination(for: TripPoll.self) { poll in
            PollDetailView(poll: poll)
        }
        .alert(
            "Error",
            isPresented: Binding(
                get: { errorMessage != nil },
                set: { if !$0 { errorMessage = nil } }
            )
        ) {
            Button("OK", role: .cancel) {
                errorMessage = nil
            }
        } message: {
            Text(errorMessage ?? "Please try again.")
        }
    }

    @ViewBuilder
    private var emptyState: some View {
        ContentUnavailableView {
            Label("No Polls", systemImage: "chart.bar.doc.horizontal")
        } description: {
            Text("Create a poll from your saved trips to let friends vote on which trip to take.")
        }
    }

    @ViewBuilder
    private var pollsList: some View {
        List {
            ForEach(polls) { poll in
                NavigationLink(value: poll) {
                    PollRowView(poll: poll)
                        .contentShape(Rectangle())
                }
            }
        }
        .listStyle(.plain)
    }

    private func loadPolls() async {
        isLoading = true
        errorMessage = nil

        do {
            polls = try await PollService.shared.fetchMyPolls()
        } catch let pollError as PollError {
            errorMessage = pollError.localizedDescription
        } catch {
            self.errorMessage = PollError.unknown(error).localizedDescription
        }

        isLoading = false
    }
}

// MARK: - Poll Row View

private struct PollRowView: View {
    @Environment(\.colorScheme) private var colorScheme
    let poll: TripPoll

    var body: some View {
        VStack(alignment: .leading, spacing: 8) {
            HStack {
                Text(poll.title)
                    .font(.headline)

                Spacer()

                Text(poll.shareCode)
                    .font(.caption)
                    .fontWeight(.semibold)
                    .foregroundStyle(Theme.warmOrange)
                    .padding(.horizontal, 8)
                    .padding(.vertical, 4)
                    .background(Theme.warmOrange.opacity(0.15))
                    .clipShape(Capsule())
            }

            HStack {
                Label("\(poll.tripSnapshots.count) trips", systemImage: "map")

                Spacer()

                Text(poll.createdAt, style: .date)
            }
            .font(.caption)
            .foregroundStyle(.secondary)
        }
        .padding(.vertical, 4)
    }
}

#Preview {
    NavigationStack {
        PollsListView()
    }
}