import MarkdownUI
import SharedUIComponents
import SwiftUI

struct PromptToCodePanel: View {
    @ObservedObject var provider: PromptToCodeProvider

    var body: some View {
        VStack(spacing: 0) {
            PromptToCodePanelContent(provider: provider)
                .overlay(alignment: .topTrailing) {
                    if !provider.code.isEmpty {
                        CopyButton {
                            NSPasteboard.general.clearContents()
                            NSPasteboard.general.setString(provider.code, forType: .string)
                        }
                        .padding(.trailing, 2)
                        .padding(.top, 2)
                    }
                }
                .overlay(alignment: .bottom) {
                    HStack {
                        if provider.isResponding {
                            Button(action: {
                                provider.stopResponding()
                            }) {
                                HStack(spacing: 4) {
                                    Image(systemName: "stop.fill")
                                    Text("Stop")
                                }
                                .padding(8)
                                .background(
                                    .regularMaterial,
                                    in: RoundedRectangle(cornerRadius: 6, style: .continuous)
                                )
                                .overlay {
                                    RoundedRectangle(cornerRadius: 6, style: .continuous)
                                        .stroke(Color(nsColor: .separatorColor), lineWidth: 1)
                                }
                            }
                            .buttonStyle(.plain)
                        }

                        let isRespondingButCodeIsReady = provider.isResponding
                            && !provider.code.isEmpty
                            && !provider.description.isEmpty

                        if !provider.isResponding || isRespondingButCodeIsReady {
                            HStack {
                                Toggle(
                                    "Continuous Mode",
                                    isOn: .init(
                                        get: { provider.isContinuous },
                                        set: { _ in provider.toggleContinuous() }
                                    )
                                )
                                .toggleStyle(.checkbox)

                                Button(action: {
                                    provider.cancel()
                                }) {
                                    Text("Cancel")
                                }
                                .buttonStyle(CommandButtonStyle(color: .gray))
                                .keyboardShortcut("w", modifiers: [.command])

                                if !provider.code.isEmpty {
                                    Button(action: {
                                        provider.acceptSuggestion()
                                    }) {
                                        Text("Accept(⌘ + ⏎)")
                                    }
                                    .buttonStyle(CommandButtonStyle(color: .indigo))
                                    .keyboardShortcut(KeyEquivalent.return, modifiers: [.command])
                                }
                            }
                            .padding(8)
                            .background(
                                .regularMaterial,
                                in: RoundedRectangle(cornerRadius: 6, style: .continuous)
                            )
                            .overlay {
                                RoundedRectangle(cornerRadius: 6, style: .continuous)
                                    .stroke(Color(nsColor: .separatorColor), lineWidth: 1)
                            }
                        }
                    }
                    .padding(.bottom, 8)
                }

            PromptToCodePanelToolbar(provider: provider)
        }
        .background(Color.contentBackground)
        .xcodeStyleFrame()
    }
}

struct PromptToCodePanelContent: View {
    @ObservedObject var provider: PromptToCodeProvider
    @Environment(\.colorScheme) var colorScheme
    @AppStorage(\.suggestionCodeFontSize) var fontSize

    var body: some View {
        CustomScrollView {
            VStack(spacing: 0) {
                Spacer(minLength: 60)

                if !provider.errorMessage.isEmpty {
                    Text(provider.errorMessage)
                        .multilineTextAlignment(.leading)
                        .foregroundColor(.white)
                        .padding(.horizontal, 8)
                        .padding(.vertical, 2)
                        .background(
                            Color.red,
                            in: RoundedRectangle(cornerRadius: 8, style: .continuous)
                        )
                        .scaleEffect(x: 1, y: -1, anchor: .center)
                }

                if !provider.description.isEmpty {
                    Markdown(provider.description)
                        .textSelection(.enabled)
                        .markdownTheme(.gitHub.text {
                            BackgroundColor(Color.clear)
                        })
                        .padding()
                        .frame(maxWidth: .infinity)
                        .scaleEffect(x: 1, y: -1, anchor: .center)
                }

                if provider.code.isEmpty {
                    Text(
                        provider.isResponding
                            ? "Thinking..."
                            : "Enter your requirement to generate code."
                    )
                    .foregroundColor(.secondary)
                    .padding()
                    .multilineTextAlignment(.center)
                    .frame(maxWidth: .infinity)
                    .scaleEffect(x: 1, y: -1, anchor: .center)
                } else {
                    CodeBlock(
                        code: provider.code,
                        language: provider.language,
                        startLineIndex: provider.startLineIndex,
                        colorScheme: colorScheme,
                        firstLinePrecedingSpaceCount: provider.startLineColumn,
                        fontSize: fontSize
                    )
                    .frame(maxWidth: .infinity)
                    .scaleEffect(x: 1, y: -1, anchor: .center)
                }

                if let name = provider.name {
                    Text(name)
                        .font(.footnote)
                        .foregroundColor(.secondary)
                        .padding(.top, 12)
                        .scaleEffect(x: 1, y: -1, anchor: .center)
                }
            }
        }
        .scaleEffect(x: 1, y: -1, anchor: .center)
    }
}

struct PromptToCodePanelToolbar: View {
    @ObservedObject var provider: PromptToCodeProvider
    @FocusState var isInputAreaFocused: Bool

    var body: some View {
        HStack {
            Button(action: {
                provider.revert()
            }) {
                Group {
                    Image(systemName: "arrow.uturn.backward")
                }
                .padding(6)
                .background {
                    Circle().fill(Color(nsColor: .controlBackgroundColor))
                }
                .overlay {
                    Circle()
                        .stroke(Color(nsColor: .controlColor), lineWidth: 1)
                }
            }
            .buttonStyle(.plain)
            .disabled(provider.isResponding || !provider.canRevert)

            HStack(spacing: 0) {
                ZStack(alignment: .center) {
                    // a hack to support dynamic height of TextEditor
                    Text(provider.requirement.isEmpty ? "Hi" : provider.requirement).opacity(0)
                        .font(.system(size: 14))
                        .frame(maxWidth: .infinity, maxHeight: 400)
                        .padding(.top, 1)
                        .padding(.bottom, 2)
                        .padding(.horizontal, 4)

                    CustomTextEditor(
                        text: $provider.requirement,
                        font: .systemFont(ofSize: 14),
                        onSubmit: { provider.sendRequirement() }
                    )
                    .padding(.top, 1)
                    .padding(.bottom, -1)
                }
                .focused($isInputAreaFocused)
                .padding(8)
                .fixedSize(horizontal: false, vertical: true)

                Button(action: {
                    provider.sendRequirement()
                }) {
                    Image(systemName: "paperplane.fill")
                        .padding(8)
                }
                .buttonStyle(.plain)
                .disabled(provider.isResponding)
                .keyboardShortcut(KeyEquivalent.return, modifiers: [])
            }
            .frame(maxWidth: .infinity)
            .background {
                RoundedRectangle(cornerRadius: 6)
                    .fill(Color(nsColor: .controlBackgroundColor))
            }
            .overlay {
                RoundedRectangle(cornerRadius: 6)
                    .stroke(Color(nsColor: .controlColor), lineWidth: 1)
            }
            .background {
                Button(action: {
                    provider.requirement += "\n"
                }) {
                    EmptyView()
                }
                .keyboardShortcut(KeyEquivalent.return, modifiers: [.shift])
            }
        }
        .onAppear {
            isInputAreaFocused = true
        }
        .padding(8)
        .background(.ultraThickMaterial)
    }
}

// MARK: - Previews

struct PromptToCodePanel_Bright_Preview: PreviewProvider {
    static var previews: some View {
        PromptToCodePanel(provider: PromptToCodeProvider(
            code: """
            ForEach(0..<viewModel.suggestion.count, id: \\.self) { index in
                Text(viewModel.suggestion[index])
                    .frame(maxWidth: .infinity, alignment: .leading)
                    .multilineTextAlignment(.leading)
            }
            """,
            language: "swift",
            description: "Hello world",
            isResponding: false,
            startLineIndex: 8
        ))
        .preferredColorScheme(.light)
        .frame(width: 450, height: 400)
    }
}

struct PromptToCodePanel_Error_Bright_Preview: PreviewProvider {
    static var previews: some View {
        PromptToCodePanel(provider: PromptToCodeProvider(
            code: """
            ForEach(0..<viewModel.suggestion.count, id: \\.self) { index in
                Text(viewModel.suggestion[index])
                    .frame(maxWidth: .infinity, alignment: .leading)
                    .multilineTextAlignment(.leading)
            }
            """,
            language: "swift",
            description: "Hello world",
            isResponding: false,
            startLineIndex: 8,
            errorMessage: "Error"
        ))
        .preferredColorScheme(.light)
        .frame(width: 450, height: 400)
    }
}