//
//  CodeBlockView.swift
//  Zyquo Cloud
//
//  Author: Simon-Pierre Boucher
//  Mail: contact@spboucher.ai
//
//  Fenced code block per the Phase 4 spec: surfaceSecondary card with medium
//  radius, uppercased language label top-left, hover copy button top-right
//  (with a brief checkmark confirmation), SF Mono content with syntax
//  highlighting, horizontal scrolling for long lines, and text selection.
//

import SwiftUI

struct CodeBlockView: View {
    let code: String
    let language: String?
    let fontSize: Double

    @State private var hovering = false
    @State private var copied = false
    @State private var copyGeneration = 0

    /// How long the copy confirmation checkmark stays visible.
    private static let copyConfirmationSeconds: Double = 1.2

    var body: some View {
        VStack(alignment: .leading, spacing: 0) {
            header
            ScrollView(.horizontal) {
                SwiftUI.Text(highlighted)
                    .font(ZyquoFont.code(size: max(fontSize - 1, 1)))
                    .textSelection(.enabled)
                    .fixedSize(horizontal: false, vertical: true)
                    .padding(.horizontal, ZyquoSpacing.sm)
                    .padding(.top, ZyquoSpacing.xxs)
                    .padding(.bottom, ZyquoSpacing.xs)
            }
        }
        .background(
            RoundedRectangle(cornerRadius: ZyquoRadius.medium, style: .continuous)
                .fill(ZyquoColor.surfaceSecondary)
        )
        .onHover { inside in
            withAnimation(ZyquoMotion.hover) { hovering = inside }
        }
    }

    // MARK: Header

    private var header: some View {
        HStack(spacing: ZyquoSpacing.xs) {
            if let language, !language.isEmpty {
                SwiftUI.Text(language.uppercased())
                    .font(ZyquoFont.caption)
                    .foregroundStyle(ZyquoColor.textSecondary)
            }
            Spacer(minLength: ZyquoSpacing.xs)
            copyButton
                .opacity(hovering || copied ? 1 : 0)
        }
        .padding(.horizontal, ZyquoSpacing.sm)
        .padding(.top, ZyquoSpacing.xs)
    }

    private var copyButton: some View {
        Button(action: copy) {
            Image(systemName: copied ? "checkmark" : "doc.on.doc")
                .font(ZyquoFont.caption)
                .foregroundStyle(copied ? ZyquoColor.success : ZyquoColor.textSecondary)
        }
        .buttonStyle(PressableButtonStyle())
        .accessibilityLabel("Copy code")
        .help("Copy code")
    }

    // MARK: Highlighting

    private var highlighted: AttributedString {
        SyntaxHighlighter.highlight(code, language: language, baseColor: ZyquoColor.textPrimary)
    }

    // MARK: Copy

    private func copy() {
        let pasteboard = NSPasteboard.general
        pasteboard.clearContents()
        pasteboard.setString(code, forType: .string)

        copyGeneration += 1
        let generation = copyGeneration
        withAnimation(ZyquoMotion.hover) { copied = true }
        Task {
            try? await Task.sleep(for: .seconds(Self.copyConfirmationSeconds))
            if generation == copyGeneration {
                withAnimation(ZyquoMotion.hover) { copied = false }
            }
        }
    }
}