import type { SearchContextContribution } from "@govoplan/core-webui";


export type SearchOverlayAnchor = {
  top: number;
  left: number;
  width: number;
  height: number;
};

export type SearchOverlayLayout = {
  top: number;
  left: number;
  width: number;
  maxHeight: number;
  inputOffset: number;
  inputWidth: number;
  inputHeight: number;
  resultsHeight: number;
};

const DESKTOP_PANEL_WIDTH = 820;
const DESKTOP_MARGIN = 16;
const MOBILE_MARGIN = 12;
const MOBILE_BREAKPOINT = 900;
const RESULTS_GAP = 8;

export function calculateSearchOverlayLayout(
  anchor: SearchOverlayAnchor,
  viewportWidth: number,
  viewportHeight: number
): SearchOverlayLayout {
  const mobile = viewportWidth < MOBILE_BREAKPOINT;
  const margin = mobile ? MOBILE_MARGIN : DESKTOP_MARGIN;
  const width = Math.max(1, Math.min(DESKTOP_PANEL_WIDTH, viewportWidth - margin * 2));
  const left = Math.max(margin, (viewportWidth - width) / 2);
  const inputWidth = width;
  const inputOffset = 0;
  const top = Math.max(0, anchor.top);
  const inputHeight = Math.max(1, anchor.height);
  const availableResultsHeight = viewportHeight - top - inputHeight - RESULTS_GAP - margin;
  const resultsHeight = Math.max(96, Math.min(620, availableResultsHeight));

  return {
    top,
    left,
    width,
    maxHeight: inputHeight + RESULTS_GAP + resultsHeight,
    inputOffset,
    inputWidth,
    inputHeight,
    resultsHeight
  };
}

export function selectSearchContext(
  contexts: readonly SearchContextContribution[],
  pathname: string
): SearchContextContribution | null {
  const matches = contexts.flatMap((context) =>
    context.pathPrefixes
      .filter((prefix) => pathMatchesPrefix(pathname, prefix))
      .map((prefix) => ({ context, prefixLength: normalizePath(prefix).length }))
  );
  matches.sort((left, right) =>
    right.prefixLength - left.prefixLength
    || (left.context.order ?? 100) - (right.context.order ?? 100)
    || left.context.id.localeCompare(right.context.id)
  );
  return matches[0]?.context ?? null;
}

function pathMatchesPrefix(pathname: string, prefix: string): boolean {
  const normalizedPath = normalizePath(pathname);
  const normalizedPrefix = normalizePath(prefix);
  return normalizedPrefix === "/"
    || normalizedPath === normalizedPrefix
    || normalizedPath.startsWith(`${normalizedPrefix}/`);
}

function normalizePath(value: string): string {
  const normalized = `/${String(value || "").trim().replace(/^\/+|\/+$/g, "")}`;
  return normalized === "/" ? normalized : normalized.replace(/\/+$/g, "");
}