import SwiftUI
import SwiftData
import AppKit
import UniformTypeIdentifiers

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?
    @State private var searchText = ""
    @State private var filter: HistoryFilter = .all
    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()

                    Menu {
                        Button("Export Selected…") { exportRuns(selection.map { [$0] } ?? []) }
                            .disabled(selection == nil)
                        Button("Export All…") { exportRuns(runs) }
                            .disabled(runs.isEmpty)
                    } label: {
                        Image(systemName: "square.and.arrow.up")
                    }
                    .menuStyle(.borderlessButton)
                    .help("Export run logs")

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

                VStack(spacing: 8) {
                    TextField("Search history", text: $searchText)
                        .textFieldStyle(.roundedBorder)
                    Picker("History filter", selection: $filter) {
                        ForEach(HistoryFilter.allCases) { item in Text(item.title).tag(item) }
                    }
                    .pickerStyle(.segmented)
                    .labelsHidden()
                }
                .padding(.horizontal, 14)
                .padding(.bottom, 10)

                Divider()

                if filteredRuns.isEmpty {
                    ContentUnavailableView(
                        "No Run History",
                        systemImage: "clock.arrow.circlepath",
                        description: Text(runs.isEmpty ? "Completed, failed and background synchronisations will appear here." : "No runs match the current search or filter.")
                    )
                    .frame(maxWidth: .infinity, maxHeight: .infinity)
                } else {
                    List(selection: $selection) {
                        ForEach(filteredRuns) { 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 var filteredRuns: [SyncRun] {
        runs.filter { run in
            let matchesSearch = searchText.isEmpty || run.jobName.localizedCaseInsensitiveContains(searchText) || run.output.localizedCaseInsensitiveContains(searchText) || run.errorOutput.localizedCaseInsensitiveContains(searchText)
            let matchesFilter: Bool
            switch filter {
            case .all: matchesFilter = true
            case .failed: matchesFilter = !run.isRunning && !run.succeeded && !run.wasCancelled
            case .successful: matchesFilter = run.succeeded
            case .automatic: matchesFilter = run.trigger == .scheduled || run.trigger == .watched
            }
            return matchesSearch && matchesFilter
        }
    }

    private func exportRuns(_ items: [SyncRun]) {
        guard !items.isEmpty else { return }
        let panel = NSSavePanel()
        panel.allowedContentTypes = [.plainText]
        panel.nameFieldStringValue = items.count == 1 ? "Rsync Studio-\(items[0].jobName)-Run.txt" : "Rsync Studio-History.txt"
        guard panel.runModal() == .OK, let url = panel.url else { return }
        let text = items.map(\.exportText).joined(separator: "\n\n" + String(repeating: "=", count: 72) + "\n\n")
        do { try text.write(to: url, atomically: true, encoding: .utf8) }
        catch { persistenceError = "Could not export history: \(error.localizedDescription)" }
    }

    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
    }
}


private enum HistoryFilter: String, CaseIterable, Identifiable {
    case all, failed, successful, automatic
    var id: String { rawValue }
    var title: String {
        switch self {
        case .all: return "All"
        case .failed: return "Failed"
        case .successful: return "Success"
        case .automatic: return "Automatic"
        }
    }
}