import SwiftUI
import Runestone

final class EditorKeyboardBridge: ObservableObject {
    weak var activeTextView: Runestone.TextView?
}

struct EditorKeyboardToolbar: View {
    @ObservedObject var bridge: EditorKeyboardBridge
    @State private var showFindBar = false
    @State private var searchQuery = ""
    @State private var isRegex = false

    var body: some View {
        VStack(spacing: 0) {
            if showFindBar {
                InlineFindBar(query: $searchQuery, isRegex: $isRegex,
                              onNext: findNext, onPrev: findPrev,
                              onDismiss: { withAnimation { showFindBar = false } })
                    .transition(.move(edge: .top).combined(with: .opacity))
                Divider()
            }
            ScrollView(.horizontal, showsIndicators: false) {
                HStack(spacing: 4) {
                    KeyToolbarButton(icon: "increase.indent", label: "Indent")   { bridge.activeTextView?.shiftRight() }
                    KeyToolbarButton(icon: "decrease.indent", label: "Unindent") { bridge.activeTextView?.shiftLeft() }
                    KeyToolbarDivider()
                    KeyToolbarButton(icon: "text.badge.slash", label: "Comment") { toggleComment() }
                    KeyToolbarDivider()
                    KeyToolbarText("(") { insertPair("(", ")") }
                    KeyToolbarText("[") { insertPair("[", "]") }
                    KeyToolbarText("{") { insertPair("{", "}") }
                    KeyToolbarDivider()
                    KeyToolbarText("->") { insert(" -> ") }
                    KeyToolbarText("??") { insert(" ?? ") }
                    KeyToolbarText("$0") { insert("$0") }
                    KeyToolbarDivider()
                    KeyToolbarButton(icon: "arrow.left",  label: "Left")  { moveCursor(-1) }
                    KeyToolbarButton(icon: "arrow.right", label: "Right") { moveCursor(+1) }
                    KeyToolbarDivider()
                    KeyToolbarButton(icon: "magnifyingglass", label: "Find") { withAnimation { showFindBar.toggle() } }
                    Spacer()
                    KeyToolbarButton(icon: "keyboard.chevron.compact.down", label: "Done") {
                        bridge.activeTextView?.resignFirstResponder()
                    }
                }
                .padding(.horizontal, 8).padding(.vertical, 6)
            }
            .background(.regularMaterial)
        }
    }

    private func insert(_ t: String) { bridge.activeTextView?.insertText(t) }
    private func insertPair(_ l: String, _ r: String) { bridge.activeTextView?.insertText(l+r); moveCursor(-1) }
    private func moveCursor(_ offset: Int) {
        guard let tv = bridge.activeTextView, let sel = tv.selectedRange else { return }
        tv.selectedRange = NSRange(location: max(0, sel.location + offset), length: 0)
    }
    private func toggleComment() {
        guard let tv = bridge.activeTextView, let sel = tv.selectedRange else { return }
        let text = tv.text as NSString
        let lr = text.lineRange(for: sel)
        let line = text.substring(with: lr)
        let trimmed = line.trimmingCharacters(in: .whitespaces)
        let indent = String(line.prefix(while: { $0 == " " || $0 == "\t" }))
        let newLine: String
        if      trimmed.hasPrefix("// ") { newLine = line.replacingFirstOccurrence(of: "// ", with: "") }
        else if trimmed.hasPrefix("//")  { newLine = line.replacingFirstOccurrence(of: "//",  with: "") }
        else                             { newLine = indent + "// " + line.dropFirst(indent.count) }
        tv.replace(lr, withText: newLine)
    }
    private func findNext() {
        guard let tv = bridge.activeTextView, !searchQuery.isEmpty else { return }
        tv.selectNextOccurrence(matching: SearchOptions(query: searchQuery))
    }
    private func findPrev() {
        guard let tv = bridge.activeTextView, !searchQuery.isEmpty else { return }
        tv.selectPreviousOccurrence(matching: SearchOptions(query: searchQuery))
    }
}

struct InlineFindBar: View {
    @Binding var query: String; @Binding var isRegex: Bool
    var onNext: () -> Void; var onPrev: () -> Void; var onDismiss: () -> Void
    var body: some View {
        HStack(spacing: 8) {
            Image(systemName: "magnifyingglass").foregroundStyle(.secondary)
            TextField("Find…", text: $query).textFieldStyle(.plain)
                .font(.system(.body, design: .monospaced)).autocorrectionDisabled().autocapitalization(.none)
                .onSubmit(onNext)
            Toggle(isOn: $isRegex) { Image(systemName: "ellipsis.curlybraces") }
                .toggleStyle(.button).buttonStyle(.bordered).tint(isRegex ? .accentColor : .secondary)
            Button(action: onPrev)    { Image(systemName: "chevron.up")   }.buttonStyle(.bordered).disabled(query.isEmpty)
            Button(action: onNext)    { Image(systemName: "chevron.down") }.buttonStyle(.bordered).disabled(query.isEmpty)
            Button(action: onDismiss) { Image(systemName: "xmark")        }.buttonStyle(.bordered)
        }
        .padding(.horizontal, 12).padding(.vertical, 6)
    }
}

struct KeyToolbarButton: View {
    let icon: String; let label: String; let action: () -> Void
    var body: some View {
        Button(action: action) { Image(systemName: icon).frame(minWidth: 32, minHeight: 32).contentShape(Rectangle()) }
            .buttonStyle(.plain).foregroundStyle(.primary).help(label)
    }
}

struct KeyToolbarText: View {
    let text: String; let action: () -> Void
    init(_ text: String, action: @escaping () -> Void) { self.text = text; self.action = action }
    var body: some View {
        Button(action: action) {
            Text(text).font(.system(.callout, design: .monospaced).bold())
                .frame(minWidth: 32, minHeight: 32).contentShape(Rectangle())
        }
        .buttonStyle(.plain).foregroundStyle(.primary)
    }
}

struct KeyToolbarDivider: View {
    var body: some View { Divider().frame(height: 20).padding(.horizontal, 2) }
}