import SwiftUI

struct SheetCell: View {
  @Bindable var model: SheetModel
  let point: Coordinate
  @Binding var editing: Coordinate?
  var select: () -> Void
  var beginEditing: () -> Void = {}
  var endEditing: () -> Void
  var columnWidth: Double? = nil
  var rowHeight: Double? = nil
  @Environment(\.colorScheme) private var scheme
  private func width(_ col: Int) -> Double { columnWidth ?? model.sizes.cols?[String(col)] ?? 110 }
  private func height(_ row: Int) -> Double { rowHeight ?? model.sizes.rows?[String(row)] ?? 32 }
  var body: some View {
    let cell = model.cells[point]
    let style = model.styles[cell?.f ?? ""]
    let alignment: Alignment =
      style?.a == "center"
      ? .center : style?.a == "right" || (style?.a == nil && cell?.n == true) ? .trailing : .leading
    return Group {
      #if os(macOS)
      if editing == point {
        SheetCellEditor(text: $model.draft, enabled: model.mayWrite && !model.busy,
          label: String(format: sheetsMacString("Edit %@"), point.ref),
          commit: { commit(right: $0) }, cancel: {
            guard !model.busy else { return }
            model.discardAll(); endEditing()
          })
          .padding(.horizontal, 5)
          .frame(width: width(point.c), height: height(point.r))
          .background(fill(style))
          .overlay { Rectangle().strokeBorder(Color.accentColor, lineWidth: 2) }
          .accessibilityLabel(String(format: sheetsMacString("Edit %@"), point.ref))
      } else { display(cell, style: style, alignment: alignment) }
      #else
      display(cell, style: style, alignment: alignment)
      #endif
    }
  }
  private func commit(right: Bool) {
    guard !model.busy, model.selection.start == point else { return }
    Task {
      await model.commit(moveRight: right)
      if !model.hasUnconfirmedChanges { endEditing() }
    }
  }
  private func display(_ cell: Cell?, style: CellStyle?, alignment: Alignment) -> some View {
    Button(action: select) {
      Text(cell?.display ?? "").font(.system(size: 13, weight: style?.b == true ? .bold : .regular))
        .italic(style?.i == true).lineLimit(1).padding(.horizontal, 5)
        .frame(width: width(point.c), height: height(point.r), alignment: alignment)
        .foregroundStyle(ink(style)).background(fill(style))
        .contentShape(.rect)
        .overlay {
          Rectangle().strokeBorder(
            model.selection.contains(point) ? Color.accentColor : Color.secondary.opacity(0.2),
            lineWidth: model.selection.contains(point) ? 2 : 0.5)
        }
    }.buttonStyle(.plain)
      .simultaneousGesture(TapGesture(count: 2).onEnded { if model.mayWrite, !model.busy, !model.hasUnconfirmedChanges { model.select(point); beginEditing() } })
      .accessibilityLabel("\(point.ref), \(cell?.display ?? "Empty")")
      .accessibilityValue(style?.lc == true ? "Imported colours have low contrast" : "")
      .accessibilityAddTraits(model.selection.contains(point) ? .isSelected : [])
  }
  private func fill(_ style: CellStyle?) -> Color {
    if let hex = style?.fx { return Color(hex: hex) }
    if let h = style?.fh, let c = style?.fc { return .oklch(scheme == .dark ? 0.30 : 0.92, c, h) }
    return Color.clear
  }
  private func ink(_ style: CellStyle?) -> Color {
    if let hex = style?.k { return Color(hex: hex) }
    if let h = style?.kh, let c = style?.kc { return .oklch(scheme == .dark ? 0.80 : 0.42, c, h) }
    return .primary
  }
}