import SwiftUI
import UniformTypeIdentifiers
import AppKit

struct MenuBarContentView: View {
    @EnvironmentObject var store: AppStore
    @State private var showingSettings = false

    var body: some View {
        Group {
            if store.isAuthenticated {
                if showingSettings {
                    SettingsView(showingSettings: $showingSettings)
                } else {
                    ComposeView(showingSettings: $showingSettings)
                }
            } else {
                SetupView()
            }
        }
        .frame(width: 320)
        .padding(16)
    }
}

// MARK: - Setup (API key entry)

struct SetupView: View {
    @EnvironmentObject var store: AppStore
    @FocusState private var keyFieldFocused: Bool

    var body: some View {
        VStack(alignment: .leading, spacing: 12) {
            Text("Connect Buffit for Mac to your Buffer Account")
                .font(.headline)
            Text("Paste your API key generated by Buffer")
                .font(.caption)
            Text("Buffer -> Settings -> API -> Personal Keys")
                .font(.caption)
            SecureField("Buffer API key", text: $store.apiKey)
                .textFieldStyle(.roundedBorder)
                .focused($keyFieldFocused)
                .onSubmit { store.connect() }

            if let error = store.loadError {
                Text(error)
                    .font(.caption)
                    .foregroundStyle(.red)
            }
            HStack(alignment: .firstTextBaseline) {
                Text("Your API key is stored on this device, no one can see it.")
                    .font(.caption)
                    .foregroundStyle(.secondary)
                    .lineLimit(nil)
                    .fixedSize(horizontal: false, vertical: true)
                    .layoutPriority(2)
                
                Spacer(minLength: 16)
                
                Button {
                    store.connect()
                } label: {
                    if store.isValidatingKey {
                        ProgressView()
                            .controlSize(.small)
                            .frame(width: 55)
                    } else {
                        HStack(spacing: 6) {
                            Text("Connect")
                                .frame(width: 55)
                            Image(systemName: "key.fill")
                        }
                    }
                }
                .layoutPriority(1)
                .keyboardShortcut(.defaultAction)
                .disabled(store.apiKey.trimmingCharacters(in: .whitespaces).isEmpty || store.isValidatingKey)
            }
            Divider()

            Button("Quit Buffit for Mac") {
                NSApplication.shared.terminate(nil)
            }
            .buttonStyle(.plain)
            .foregroundStyle(.secondary)
            .font(.caption)

        }
        .onAppear { keyFieldFocused = true }
    }
}

// MARK: - Settings

struct SettingsView: View {
    @EnvironmentObject var store: AppStore
    @Binding var showingSettings: Bool

    var body: some View {
        VStack(alignment: .leading, spacing: 14) {
            HStack {
                Button {
                    showingSettings = false
                } label: {
                    Image(systemName: "chevron.left")
                }
                .buttonStyle(.plain)

                Text("Settings")
                    .font(.headline)
                Spacer()
            }

            VStack(alignment: .leading, spacing: 6) {
                Text("Default for new posts")
                    .font(.subheadline)
                    .fontWeight(.medium)

                Picker("", selection: $store.defaultMode) {
                    ForEach(DefaultPostMode.allCases) { mode in
                        Text(mode.label).tag(mode)
                    }
                }
                .pickerStyle(.radioGroup)
                .labelsHidden()

                Text("If a channel's queue is full (10 posts on the free plan), that post is saved as a draft automatically, even when the default above is set to queue.")
                    .font(.caption)
                    .foregroundStyle(.secondary)
                    .fixedSize(horizontal: false, vertical: true)
            }

            Divider()
            Link("Support and website", destination: URL(string: "https://danielmorrisey.com/buffit")!)
            Link("Privacy policy", destination: URL(string: "https://danielmorrisey.com/buffit/privacy")!)
            Divider()
            HStack(spacing: 6) {
                Image(systemName: "hand.raised.fill")
                Text("How your data is handled")
            }
            Text("Posts and your Buffer API key are sent directly to Buffer. If you attach an image, it is uploaded to Buffit's media service so Buffer can retrieve it when publishing. Your API key stays in your Mac's Keychain.")
                .font(.caption)
                .foregroundStyle(.secondary)
                .fixedSize(horizontal: false, vertical: true)
            Divider()
            Button(action: { store.disconnect() }) {
                HStack(spacing: 6) {
                    Image(systemName: "rectangle.portrait.and.arrow.right")
                    Text("Sign Out")
                }
            }
            .buttonStyle(.plain)
            .foregroundStyle(.secondary)
            .font(.caption)

            Button(action: { NSApplication.shared.terminate(nil) }) {
                HStack(spacing: 6) {
                    Image(systemName: "power")
                    Text("Quit Buffit")
                }
            }
            .buttonStyle(.plain)
            .foregroundStyle(.secondary)
            .font(.caption)
        }
    }
}

// MARK: - Compose (write + queue)

struct ComposeView: View {
    @EnvironmentObject var store: AppStore
    @Binding var showingSettings: Bool
    @FocusState private var textFocused: Bool

    var body: some View {
        VStack(alignment: .leading, spacing: 10) {
            HStack {
                Text("Compose Post to add to Queue")
                    .font(.headline)
                Spacer()

                Menu {
                    ForEach(store.channels) { channel in
                        Button {
                            store.toggleChannel(channel.id)
                        } label: {
                            HStack {
                                Text(channel.name)
                                if store.selectedChannelIds.contains(channel.id) {
                                    Image(systemName: "checkmark")
                                }
                            }
                        }
                    }
                    Divider()
                    Button("Select All") { store.selectAllChannels() }
                } label: {
                    Image(systemName: "list.bullet")
                }
                .menuStyle(.borderlessButton)
                .fixedSize()

                Button {
                    showingSettings = true
                } label: {
                    Image(systemName: "gearshape")
                }
                .buttonStyle(.plain)

                Group {
                    if store.isRefreshingChannels {
                        ProgressView()
                            .controlSize(.small)
                            .frame(width: 24, height: 24)
                    } else {
                        Button {
                            Task {
                                await store.refreshChannels()
                            }
                        } label: {
                            Image(systemName: "arrow.clockwise")
                        }
                        .buttonStyle(.plain)
                        .disabled(store.isRefreshingChannels)
                    }
                }
                .fixedSize()
            }

            ZStack(alignment: .topLeading) {
                if store.postText.isEmpty {
                    Text("Start typing here...")
                        .foregroundStyle(.tertiary)
                        .padding(.top, 8)
                        .padding(.leading, 5)
                }
                TextEditor(text: $store.postText)
                    .frame(height: 90)
                    .font(.system(size: 13))
                    .scrollContentBackground(.hidden)
                    .focused($textFocused)
            }
            .padding(4)
            .background(RoundedRectangle(cornerRadius: 6).fill(Color(nsColor: .textBackgroundColor)))
            .overlay(RoundedRectangle(cornerRadius: 6).stroke(Color.secondary.opacity(0.25)))

            if let image = store.attachedImage {
                HStack(spacing: 12) {
                    Image(systemName: "photo.fill")
                        .font(.title3)
                        .foregroundStyle(.blue)
                    VStack(alignment: .leading, spacing: 2) {
                        Text("Image attached")
                            .font(.caption)
                            .fontWeight(.medium)
                        Text("\(image.size) bytes")
                            .font(.caption2)
                            .foregroundStyle(.secondary)
                    }
                    Spacer()
                    Button {
                        store.removeAttachedImage()
                    } label: {
                        Image(systemName: "xmark.circle.fill")
                            .foregroundStyle(.secondary)
                    }
                    .buttonStyle(.plain)
                }
                .padding(8)
                .background(Color.blue.opacity(0.1))
                .cornerRadius(6)
            } else {
                Button {
                    let panel = NSOpenPanel()
                    panel.allowedContentTypes = [.image]
                    panel.allowsMultipleSelection = false
                    panel.canChooseFiles = true
                    panel.canChooseDirectories = false

                    if panel.runModal() == .OK, let url = panel.url {
                        store.attachImage(fileURL: url)
                    }
                } label: {
                    HStack(spacing: 6) {
                        Image(systemName: "photo.badge.plus")
                        Text("Upload Image")
                    }
                    .font(.caption)
                }
                .buttonStyle(.bordered)
                .frame(maxWidth: .infinity, alignment: .leading)
                .disabled(store.isUploadingImage)
            }

            if let error = store.imageUploadError {
                Text(error)
                    .font(.caption)
                    .foregroundStyle(.red)
            }

            ChannelChipRow()

            statusView

            HStack {
                Text("\(store.postText.count) characters")
                    .font(.caption2)
                    .foregroundStyle(.secondary)
                Spacer()
                Button {
                    store.addToQueue()
                } label: {
                    if store.isPosting {
                        ProgressView().controlSize(.small)
                    } else {
                        Text(store.defaultMode == .queue ? "Add to Queue" : "Save as Draft")
                    }
                }
                .keyboardShortcut(.defaultAction)
                .keyboardShortcut(.return, modifiers: [.command])
                .disabled(!store.canPost)
            }
        }
        .onAppear { textFocused = true }
    }

    @ViewBuilder
    var statusView: some View {
        switch store.status {
        case .idle, .posting:
            EmptyView()
        case .done(let queued, let drafted, let failed):
            Text(summary(queued: queued, drafted: drafted, failed: failed))
                .font(.caption)
                .foregroundStyle(failed == 0 ? .green : .orange)
        case .error(let message):
            Text(message)
                .font(.caption)
                .foregroundStyle(.red)
        }
    }

    private func summary(queued: Int, drafted: Int, failed: Int) -> String {
        var parts: [String] = []
        if queued > 0 { parts.append("\(queued) queued") }
        if drafted > 0 { parts.append("\(drafted) drafted") }
        if failed > 0 { parts.append("\(failed) failed") }
        return parts.joined(separator: ", ") + "."
    }
}

// MARK: - Channel selection chips

struct ChannelChipRow: View {
    @EnvironmentObject var store: AppStore

    var body: some View {
        if store.isRefreshingChannels {
            ProgressView()
                .frame(maxWidth: .infinity)
                .padding(.vertical, 6)
        } else if store.channels.isEmpty {
            Text("No connected channels found on this Buffer account.")
                .font(.caption)
                .foregroundStyle(.secondary)
        } else {
            FlowLayout(spacing: 6) {
                ForEach(store.channels) { channel in
                    let selected = store.selectedChannelIds.contains(channel.id)
                    Button {
                        store.toggleChannel(channel.id)
                    } label: {
                        Text(channel.name)
                            .font(.caption)
                            .padding(.horizontal, 8)
                            .padding(.vertical, 4)
                            .background(
                                Capsule().fill(selected ? Color.accentColor.opacity(0.2) : Color.secondary.opacity(0.12))
                            )
                            .overlay(
                                Capsule().stroke(selected ? Color.accentColor : Color.clear, lineWidth: 1)
                            )
                            .foregroundStyle(selected ? Color.accentColor : Color.secondary)
                    }
                    .buttonStyle(.plain)
                }
            }
        }
    }
}

/// Simple wrapping layout for the channel chips.
struct FlowLayout: Layout {
    var spacing: CGFloat = 6

    func sizeThatFits(proposal: ProposedViewSize, subviews: Subviews, cache: inout ()) -> CGSize {
        let width = proposal.width ?? 300
        var x: CGFloat = 0
        var y: CGFloat = 0
        var rowHeight: CGFloat = 0

        for subview in subviews {
            let size = subview.sizeThatFits(.unspecified)
            if x + size.width > width, x > 0 {
                x = 0
                y += rowHeight + spacing
                rowHeight = 0
            }
            x += size.width + spacing
            rowHeight = max(rowHeight, size.height)
        }
        return CGSize(width: width, height: y + rowHeight)
    }

    func placeSubviews(in bounds: CGRect, proposal: ProposedViewSize, subviews: Subviews, cache: inout ()) {
        var x: CGFloat = bounds.minX
        var y: CGFloat = bounds.minY
        var rowHeight: CGFloat = 0

        for subview in subviews {
            let size = subview.sizeThatFits(.unspecified)
            if x + size.width > bounds.maxX, x > bounds.minX {
                x = bounds.minX
                y += rowHeight + spacing
                rowHeight = 0
            }
            subview.place(at: CGPoint(x: x, y: y), proposal: ProposedViewSize(size))
            x += size.width + spacing
            rowHeight = max(rowHeight, size.height)
        }
    }
}