import SwiftUI
import SwiftData

struct RunHistoryView: View {
    @Environment(\.modelContext) private var modelContext
    @Query(sort: \SyncRun.startedAt, order: .reverse) private var runs: [SyncRun]
    @State private var selection: SyncRun?
    @State private var persistenceError: String?
    let onBack: () -> Void

    var body: some View {
        HSplitView {
            VStack(spacing: 0) {
                HStack(spacing: 10) {
                    VStack(alignment: .leading, spacing: 2) {
                        Text("Recent Runs")
                            .font(.headline)
                        Text("\(runs.count) recorded")
                            .font(.caption)
                            .foregroundStyle(.secondary)
                    }

                    Spacer()

                    Button("Clear", role: .destructive) {
                        runs.forEach(modelContext.delete)
                        selection = nil
                        saveHistoryChanges()
                    }
                    .buttonStyle(.bordered)
                    .controlSize(.small)
                    .disabled(runs.isEmpty)
                }
                .padding(14)

                Divider()

                if runs.isEmpty {
                    ContentUnavailableView(
                        "No Run History",
                        systemImage: "clock.arrow.circlepath",
                        description: Text("Completed, failed and background synchronisations will appear here.")
                    )
                    .frame(maxWidth: .infinity, maxHeight: .infinity)
                } else {
                    List(selection: $selection) {
                        ForEach(runs) { run in
                            HStack(spacing: 11) {
                                Image(systemName: statusIcon(run))
                                    .foregroundStyle(statusColour(run))

                                VStack(alignment: .leading, spacing: 4) {
                                    HStack {
                                        Text(run.jobName)
                                            .fontWeight(.semibold)
                                            .lineLimit(1)
                                        Spacer()
                                        StatusBadge(run: run)
                                    }

                                    Text(run.startedAt, format: .dateTime.day().month(.abbreviated).year().hour().minute())
                                        .font(.caption)
                                        .foregroundStyle(.secondary)

                                    HStack(spacing: 6) {
                                        Label(run.trigger.title, systemImage: run.trigger.systemImage)
                                            .font(.caption2.weight(.semibold))
                                            .foregroundStyle(run.trigger == .watched ? Color.purple : Color.blue)
                                        if run.wasDryRun {
                                            Text("Dry run")
                                                .font(.caption2.weight(.semibold))
                                                .foregroundStyle(.blue)
                                        }
                                    }
                                }
                            }
                            .padding(.vertical, 3)
                            .tag(run)
                            .contextMenu {
                                Button("Delete Log", role: .destructive) {
                                    if selection?.id == run.id { selection = nil }
                                    modelContext.delete(run)
                                    saveHistoryChanges()
                                }
                            }
                        }
                    }
                    .listStyle(.sidebar)
                }
            }
            .frame(minWidth: 300, idealWidth: 340, maxWidth: 390)

            Group {
                if let selection {
                    RunLogView(run: selection)
                } else {
                    ContentUnavailableView(
                        "Select a Run",
                        systemImage: "clock.arrow.circlepath",
                        description: Text("Select a completed or failed run to inspect its summary and full log.")
                    )
                }
            }
            .frame(minWidth: 620, maxWidth: .infinity, maxHeight: .infinity)
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
        .alert("Database Error", isPresented: Binding(
            get: { persistenceError != nil },
            set: { if !$0 { persistenceError = nil } }
        )) {
            Button("OK", role: .cancel) { persistenceError = nil }
        } message: {
            Text(persistenceError ?? "Unable to update run history.")
        }
    }

    private func saveHistoryChanges() {
        do { try modelContext.save() }
        catch { persistenceError = error.localizedDescription }
    }

    private func statusIcon(_ run: SyncRun) -> String {
        if run.isRunning { return "arrow.triangle.2.circlepath" }
        if run.wasCancelled { return "xmark.circle.fill" }
        return run.succeeded ? "checkmark.circle.fill" : "exclamationmark.triangle.fill"
    }

    private func statusColour(_ run: SyncRun) -> Color {
        if run.isRunning { return .blue }
        if run.wasCancelled { return .secondary }
        return run.succeeded ? .green : .orange
    }
}