import SwiftUI

struct TaskPanelView: View {
    @ObservedObject var taskStore: TaskStore

    var body: some View {
        ScrollView {
            VStack(spacing: 12) {
                if taskStore.sortedTasks.isEmpty {
                    emptyState
                } else {
                    ForEach(taskStore.sortedTasks) { task in
                        TaskCardView(task: task)
                    }
                }
            }
            .padding()
        }
        .navigationTitle("Background tasks")
        #if DEBUG
        .toolbar {
            ToolbarItem(placement: .topBarTrailing) {
                Button("Sample", action: { taskStore.injectSampleEvents() })
                    .font(.caption)
            }
        }
        #endif
    }

    private var emptyState: some View {
        VStack(spacing: 8) {
            Text("Nothing running")
                .font(.headline)
            Text("Ask Hope to research or compare something.")
                .font(.subheadline)
                .foregroundStyle(.secondary)
                .multilineTextAlignment(.center)
        }
        .frame(maxWidth: .infinity)
        .padding(.vertical, 48)
    }
}

struct TaskCardView: View {
    let task: TaskItem

    var body: some View {
        VStack(alignment: .leading, spacing: 8) {
            HStack(spacing: 8) {
                statusDot
                Text(task.description)
                    .font(.subheadline.weight(.semibold))
                    .lineLimit(2)
                Spacer()
            }
            if !task.steps.isEmpty {
                VStack(alignment: .leading, spacing: 4) {
                    ForEach(task.steps) { step in
                        HStack(alignment: .top, spacing: 6) {
                            Text(stepLabel(step.role))
                                .font(.caption2.weight(.semibold))
                                .foregroundStyle(stepColor(step.role))
                            Text(step.content ?? "")
                                .font(.caption)
                                .foregroundStyle(stepColor(step.role))
                                .lineLimit(3)
                        }
                    }
                }
            }
            if let result = task.result {
                block(result, color: .green, background: Color.green.opacity(0.12))
            }
            if let error = task.error {
                block(error, color: .red, background: Color.red.opacity(0.12))
            }
        }
        .padding(12)
        .frame(maxWidth: .infinity, alignment: .leading)
        .background(Color(.secondarySystemBackground), in: RoundedRectangle(cornerRadius: 14))
    }

    private var statusDot: some View {
        Circle()
            .fill(dotColor)
            .frame(width: 9, height: 9)
    }

    private var dotColor: Color {
        switch task.status {
        case .pending: return .gray
        case .running: return .blue
        case .completed: return .green
        case .failed: return .red
        }
    }

    private func block(_ text: String, color: Color, background: Color) -> some View {
        Text(text)
            .font(.subheadline)
            .foregroundStyle(color)
            .frame(maxWidth: .infinity, alignment: .leading)
            .padding(10)
            .background(background, in: RoundedRectangle(cornerRadius: 10))
    }

    private func stepLabel(_ role: String?) -> String {
        switch role {
        case "thinking": return "Thinking"
        case "tool_call": return "Tool"
        case "tool_result": return "Result"
        case "text": return "Note"
        default: return role ?? "Step"
        }
    }

    private func stepColor(_ role: String?) -> Color {
        switch role {
        case "thinking": return .blue
        case "tool_call": return .indigo
        case "tool_result": return .secondary
        default: return .primary
        }
    }
}

#Preview {
    NavigationStack {
        TaskPanelView(taskStore: {
            let store = TaskStore()
            #if DEBUG
            store.injectSampleEvents()
            #endif
            return store
        }())
    }
}