import NorgKit
import SwiftUI

/// Typography and colours used when rendering a Norg document.
public struct NorgTheme: Sendable {

  /// Font for a heading at the given (1-based) level.
  public var heading: @Sendable (Int) -> Font
  /// Base font for body text, list items and paragraphs.
  public var body: Font
  /// Font for the title of a definition, footnote or table cell.
  public var termFont: Font
  /// Foreground colour for `verbatim` inline spans.
  public var verbatimColor: Color
  /// Foreground colour for `spoiler` inline spans.
  public var spoilerForeground: Color
  /// Background colour for `spoiler` inline spans.
  public var spoilerBackground: Color
  /// Foreground colour applied to link spans.
  public var linkColor: Color
  /// Baseline offset applied to `superscript` spans.
  public var superscriptOffset: CGFloat
  /// Baseline offset applied to `subscript` spans.
  public var subscriptOffset: CGFloat
  /// Foreground colour for block quotes.
  public var quoteColor: Color
  /// Fill colour for the vertical bar drawn alongside a quote.
  public var quoteBarColor: Color
  /// Background fill for fenced code blocks and ranged tags.
  public var codeBackground: AnyShapeStyle
  /// Font for code block and ranged-tag contents.
  public var codeFont: Font
  /// Horizontal indentation applied per nesting level.
  public var indentWidth: CGFloat
  /// Tint for a task's status symbol.
  public var statusTint: @Sendable (TaskStatus) -> Color
  /// SF Symbol name for a task's status symbol.
  public var statusSymbol: @Sendable (TaskStatus) -> String
  /// Localized label for a task status, shown in the status menu and used
  /// for accessibility. Defaults to ``TaskStatus/displayName``; override to
  /// supply wording from your own string catalog.
  public var statusLabel: @Sendable (TaskStatus) -> LocalizedStringResource

  public init(
    heading: @escaping @Sendable (Int) -> Font,
    body: Font,
    termFont: Font,
    verbatimColor: Color,
    spoilerForeground: Color,
    spoilerBackground: Color,
    linkColor: Color,
    superscriptOffset: CGFloat,
    subscriptOffset: CGFloat,
    quoteColor: Color,
    quoteBarColor: Color,
    codeBackground: AnyShapeStyle,
    codeFont: Font,
    indentWidth: CGFloat,
    statusTint: @escaping @Sendable (TaskStatus) -> Color,
    statusSymbol: @escaping @Sendable (TaskStatus) -> String,
    statusLabel: @escaping @Sendable (TaskStatus) -> LocalizedStringResource = { $0.displayName }
  ) {
    self.heading = heading
    self.body = body
    self.termFont = termFont
    self.verbatimColor = verbatimColor
    self.spoilerForeground = spoilerForeground
    self.spoilerBackground = spoilerBackground
    self.linkColor = linkColor
    self.superscriptOffset = superscriptOffset
    self.subscriptOffset = subscriptOffset
    self.quoteColor = quoteColor
    self.quoteBarColor = quoteBarColor
    self.codeBackground = codeBackground
    self.codeFont = codeFont
    self.indentWidth = indentWidth
    self.statusTint = statusTint
    self.statusSymbol = statusSymbol
    self.statusLabel = statusLabel
  }

  /// The default theme.
  public static let `default` = NorgTheme(
    heading: { level in
      switch level {
      case 1: return .title.bold()
      case 2: return .title2.bold()
      case 3: return .title3.bold()
      case 4: return .headline
      case 5: return .subheadline.bold()
      default: return .subheadline
      }
    },
    body: .body,
    termFont: .body.bold(),
    verbatimColor: .pink,
    spoilerForeground: .secondary,
    spoilerBackground: .secondary.opacity(0.25),
    linkColor: .accentColor,
    superscriptOffset: 5,
    subscriptOffset: -3,
    quoteColor: .secondary,
    quoteBarColor: .secondary,
    codeBackground: AnyShapeStyle(.quaternary),
    codeFont: .system(.callout, design: .monospaced),
    indentWidth: 18,
    statusTint: { status in
      switch status {
      case .done: return .green
      case .urgent: return .red
      case .pending: return .blue
      default: return .secondary
      }
    },
    statusSymbol: { status in
      switch status {
      case .undone: return "circle"
      case .done: return "checkmark.circle.fill"
      case .needsInput: return "questionmark.circle"
      case .urgent: return "exclamationmark.circle"
      case .recurring: return "repeat.circle"
      case .pending: return "ellipsis.circle"
      case .onHold: return "pause.circle"
      case .cancelled: return "xmark.circle"
      }
    }
  )
}