///|
/// Structural accessibility and safety checks for generated SVG.
pub(all) struct SvgAudit {
  has_title : Bool
  has_description : Bool
  has_aria_labelledby : Bool
  has_role_img : Bool
  has_unsafe_script : Bool
  issue_count : Int
} derive(Eq, Debug)

///|
/// A report bundle with visual and non-visual representations.
pub(all) struct ReportArtifact {
  svg : String
  markdown : String
  alt_text : String
  summary : ChartSummary
  audit : SvgAudit
} derive(Eq, Debug)

///|
pub fn SvgAudit::passed(self : SvgAudit) -> Bool {
  self.issue_count == 0
}

///|
/// Audits the accessibility contract used by MoonChartKit report artifacts.
pub fn audit_svg(svg : String) -> SvgAudit {
  let has_title = svg.contains(" ReportArtifact {
  let summary = ChartSummary::from_points(points)
  let svg = render_accessible_svg(
    title,
    description,
    points,
    trend,
    summary,
    size,
    theme,
  )
  let markdown = render_markdown_report(title, description, points, summary)
  let alt_text = "\{title}. \{description}. \{summary.count} categories, total \{summary.total}, average \{summary.average}, maximum \{summary.max}."
  { svg, markdown, alt_text, summary, audit: audit_svg(svg) }
}

///|
fn render_accessible_svg(
  title : String,
  description : String,
  points : Array[DataPoint],
  trend : Array[Int],
  summary : ChartSummary,
  size : ChartSize,
  theme : ChartTheme,
) -> String {
  let area = size.plot_area()
  let chart_top = area.y + 146
  let chart_height = normalize_positive(area.height - 166, 1)
  let left_width = area.width / 2
  let trend_left = area.x + left_width + 48
  let trend_width = normalize_positive(area.width - left_width - 48, 1)
  let max = normalize_positive(summary.max, 1)
  let buf = StringBuilder()
  buf.write_string(
    "")
  buf.to_string()
}

///|
fn render_markdown_report(
  title : String,
  description : String,
  points : Array[DataPoint],
  summary : ChartSummary,
) -> String {
  let buf = StringBuilder()
  buf.write_string("## \{escape_markdown(title)}\n\n")
  buf.write_string("\{escape_markdown(description)}\n\n")
  buf.write_string(
    "Total: **\{summary.total}** | Average: **\{summary.average}** | Max: **\{summary.max}**\n\n",
  )
  buf.write_string("| Label | Value | Share |\n| --- | ---: | ---: |\n")
  for point in points {
    buf.write_string(
      "| \{escape_markdown(point.label)} | \{point.value} | \{percent_of(point.value, summary.total)}% |\n",
    )
  }
  buf.to_string()
}

///|
fn escape_markdown(value : String) -> String {
  value
  .replace(old="\\", new="\\\\")
  .replace(old="|", new="\\|")
  .replace(old="<", new="<")
  .replace(old=">", new=">")
}