import type { ColumnCellKind } from "../components/data-table/types"

/** Matches DataTable's empty-group sentinel. */
export const GROUP_ROW_EMPTY_KEY = "—"

/** Unit separator — unlikely inside person names; stable array grouping. */
const GROUP_ARRAY_SEP = "\u001f"

/**
 * Stable string key for grouping rows by a column value. Avoids `[object Object]`
 * when the field holds arrays (people-rail, tags) or plain objects.
 */
export function groupRowKey(value: unknown, cellKind?: ColumnCellKind): string {
  if (value == null || value === "") return GROUP_ROW_EMPTY_KEY

  if (cellKind === "people-rail" && Array.isArray(value)) {
    return value
      .map(item => {
        if (item && typeof item === "object") {
          const person = item as { name?: string; initials?: string }
          return `${person.initials ?? ""}|${person.name ?? ""}`
        }
        return String(item)
      })
      .sort()
      .join(GROUP_ARRAY_SEP)
  }

  if (cellKind === "tags" && Array.isArray(value)) {
    return value.map(String).sort().join(GROUP_ARRAY_SEP)
  }

  if (typeof value === "object") {
    if (cellKind === "person") {
      const person = value as { name?: string; email?: string }
      return person.name ?? person.email ?? GROUP_ROW_EMPTY_KEY
    }
    try {
      return JSON.stringify(value)
    } catch {
      return GROUP_ROW_EMPTY_KEY
    }
  }

  return String(value)
}

/** Screen-reader / count-badge label for non-chip group headings. */
export function groupRowAccessibilityLabel(
  value: unknown,
  cellKind: ColumnCellKind | undefined,
  fallbackKey: string,
): string {
  if (fallbackKey === GROUP_ROW_EMPTY_KEY) return "None"

  if (cellKind === "people-rail" && Array.isArray(value)) {
    const names = value
      .map(item => (item && typeof item === "object" ? (item as { name?: string }).name : undefined))
      .filter((name): name is string => Boolean(name))
    return names.length > 0 ? names.join(", ") : "None"
  }

  if (cellKind === "person" && value && typeof value === "object") {
    const person = value as { name?: string }
    return person.name ?? fallbackKey
  }

  return fallbackKey
}