import SwiftUI
import ProxyCore
import GRDB

struct ComposeListView: View {
    @State private var requests: [ComposeRequest] = []
    @State private var showClearConfirmation = false
    @State private var showTemplatePicker = false
    @State private var observation: AnyDatabaseCancellable?

    private let composeRepo = ComposeRepository()

    var body: some View {
        Group {
            if requests.isEmpty {
                EmptyStateView(
                    icon: "square.and.pencil",
                    title: "No Requests",
                    subtitle: "Create a new request to get started.",
                    actionTitle: "New Request"
                ) {
                    createEmptyRequest()
                }
            } else {
                List {
                    ForEach(requests) { request in
                        NavigationLink(value: request.id) {
                            HStack {
                                MethodBadge(method: request.method)
                                VStack(alignment: .leading, spacing: 2) {
                                    Text(request.name)
                                        .font(.subheadline.weight(.medium))
                                    if let url = request.url, !url.isEmpty {
                                        Text(url)
                                            .font(.caption)
                                            .foregroundStyle(.secondary)
                                            .lineLimit(1)
                                    }
                                    if let ts = request.lastSentAt {
                                        Text(formatTimestamp(ts))
                                            .font(.caption2)
                                            .foregroundStyle(.tertiary)
                                    }
                                }
                                Spacer()
                                if let status = request.responseStatus {
                                    StatusBadge(statusCode: status)
                                }
                            }
                        }
                    }
                    .onDelete { indexSet in
                        for index in indexSet {
                            if let id = requests[index].id {
                                try? composeRepo.delete(id: id)
                            }
                        }
                    }
                }
                .navigationDestination(for: Int64?.self) { id in
                    if let id {
                        ComposeEditorView(requestId: id)
                    }
                }
            }
        }
        .navigationTitle("Compose")
        .toolbar {
            ToolbarItem(placement: .topBarLeading) {
                Button {
                    showClearConfirmation = true
                } label: {
                    Image(systemName: "trash")
                }
                .disabled(requests.isEmpty)
            }
            ToolbarItem(placement: .topBarTrailing) {
                Menu {
                    Button("Empty Request") { createEmptyRequest() }
                    Button("GET with Query") { createTemplate(method: "GET", name: "GET with Query") }
                    Button("POST with JSON") { createTemplate(method: "POST", name: "POST with JSON", contentType: "application/json") }
                    Button("POST with Form") { createTemplate(method: "POST", name: "POST with Form", contentType: "application/x-www-form-urlencoded") }
                    Divider()
                    Button("Import from cURL") { showTemplatePicker = true }
                } label: {
                    Image(systemName: "plus")
                }
            }
        }
        .confirmationDialog("Clear History", isPresented: $showClearConfirmation) {
            Button("Clear All", role: .destructive) {
                try? composeRepo.deleteAll()
            }
        } message: {
            Text("This will permanently delete all compose requests.")
        }
        .sheet(isPresented: $showTemplatePicker) {
            CURLImportView { parsed in
                var request = ComposeRequest(
                    name: "Imported Request",
                    method: parsed.method,
                    url: parsed.url,
                    headers: encodeHeaders(parsed.headers),
                    body: parsed.body
                )
                try? composeRepo.insert(&request)
                showTemplatePicker = false
            }
        }
        .task {
            observation = composeRepo.observeRequests()
                .start(in: DatabaseManager.shared.dbPool) { error in
                    print("Compose observation error: \(error)")
                } onChange: { newRequests in
                    withAnimation {
                        requests = newRequests
                    }
                }
        }
    }

    private func createEmptyRequest() {
        var request = ComposeRequest()
        try? composeRepo.insert(&request)
    }

    private func createTemplate(method: String, name: String, contentType: String? = nil) {
        var headers: String?
        if let contentType {
            headers = encodeHeaders([(key: "Content-Type", value: contentType)])
        }
        var request = ComposeRequest(name: name, method: method, headers: headers)
        try? composeRepo.insert(&request)
    }

    private func formatTimestamp(_ ts: Double) -> String {
        let date = Date(timeIntervalSince1970: ts)
        let formatter = RelativeDateTimeFormatter()
        formatter.unitsStyle = .abbreviated
        return "Sent \(formatter.localizedString(for: date, relativeTo: Date()))"
    }

    private func encodeHeaders(_ headers: [(key: String, value: String)]) -> String? {
        var dict: [String: String] = [:]
        for h in headers { dict[h.key] = h.value }
        guard let data = try? JSONEncoder().encode(dict) else { return nil }
        return String(data: data, encoding: .utf8)
    }
}