// Drops in the editor (spec §8.4): the addresses of drop files, the names
// shared files take, and the words the Drops view shows. No vscode imports,
// so it is tested with plain Node.

import type * as api from "./hubapi";
import { ago } from "./flowview";

export const DROP_SCHEME = "oxygenhub-drop";

/** Which drop file a document is: the hub, the drop's id, and the file's name ("" for the drop itself). */
export interface DropRef {
  base: string;
  id: string;
  name: string;
}

/** A drop file's URI parts: `/ID/NAME`, the hub in the query. */
export function dropUriParts(r: DropRef): { path: string; query: string } {
  return { path: `/${r.id}${r.name ? `/${r.name}` : ""}`, query: new URLSearchParams({ hub: r.base }).toString() };
}

/** Parse a drop file's URI parts back; undefined if they are not one. */
export function parseDropUri(path: string, query: string): DropRef | undefined {
  const base = new URLSearchParams(query).get("hub");
  const m = /^\/([0-9a-f]{24})(?:\/(.+))?$/.exec(path);
  if (!base || !m) {
    return undefined;
  }
  return { base, id: m[1], name: m[2] ?? "" };
}

/**
 * A drop's id from what someone pastes: the id, or its page on a hub
 * (`https://hub/OWNER/drops/ID` or `https://hub/drops/ID`).
 */
export function dropIdOf(text: string): string | undefined {
  const t = text.trim();
  if (/^[0-9a-f]{24}$/.test(t)) {
    return t;
  }
  const m = /\/drops\/([0-9a-f]{24})(?:[/?#].*)?$/.exec(t);
  return m ? m[1] : undefined;
}

/** The hub a pasted drop page is on, if it is a URL. */
export function dropBaseOf(text: string): string | undefined {
  const m = /^(https?:\/\/[^/]+)\//.exec(text.trim());
  return m ? m[1] : undefined;
}

/**
 * Names for files shared as one drop: each file's path below the folder
 * they all sit in, so two `index.ts` in different folders stay apart and a
 * single file keeps just its name. Paths use `/`.
 */
export function shareNames(paths: string[]): string[] {
  const parts = paths.map((p) => p.split(/[\\/]/).filter(Boolean));
  if (parts.length === 1) {
    return [parts[0][parts[0].length - 1]];
  }
  let common = 0;
  const shortest = Math.min(...parts.map((p) => p.length - 1));
  while (common < shortest && parts.every((p) => p[common] === parts[0][common])) {
    common++;
  }
  return parts.map((p) => p.slice(common).join("/"));
}

/** File extensions for a language with no file behind it (an untitled editor). */
const EXTENSIONS: Record<string, string> = {
  typescript: "ts",
  typescriptreact: "tsx",
  javascript: "js",
  javascriptreact: "jsx",
  rust: "rs",
  python: "py",
  go: "go",
  java: "java",
  c: "c",
  cpp: "cpp",
  csharp: "cs",
  shellscript: "sh",
  markdown: "md",
  json: "json",
  yaml: "yaml",
  toml: "toml",
  html: "html",
  css: "css",
  sql: "sql",
  ruby: "rb",
  php: "php",
  swift: "swift",
  kotlin: "kt",
  plaintext: "txt",
};

/** The name a selection is shared under: the file's own name, else `snippet.EXT` by its language. */
export function snippetName(fileName: string | undefined, languageId: string): string {
  if (fileName) {
    const base = fileName.split(/[\\/]/).pop();
    if (base) {
      return base;
    }
  }
  return `snippet.${EXTENSIONS[languageId] ?? "txt"}`;
}

/** A shared selection's title: the file and its lines. */
export function snippetTitle(name: string, startLine: number, endLine: number, whole: boolean): string {
  if (whole) {
    return name;
  }
  return startLine === endLine ? `${name}, line ${startLine}` : `${name}, lines ${startLine}–${endLine}`;
}

/** The text a selection shares: the selected lines' text with its shared indentation removed. */
export function dedent(text: string): string {
  const lines = text.replace(/\r\n/g, "\n").split("\n");
  const indents = lines.filter((l) => l.trim()).map((l) => /^[ \t]*/.exec(l)![0].length);
  const cut = indents.length ? Math.min(...indents) : 0;
  return lines.map((l) => l.slice(cut)).join("\n");
}

/** The HTML that embeds a drop in another page. */
export function embedSnippet(d: Pick<api.Drop, "embed_url" | "title" | "id">): string {
  const title = (d.title || d.id).replace(/"/g, "&quot;");
  return `<iframe src="${d.embed_url ?? ""}" title="${title}" width="100%" height="400" style="border:0" loading="lazy"></iframe>`;
}

/** A drop's line in the Drops view: its title, and what it holds. */
export function dropLabel(d: api.Drop): { label: string; description: string } {
  const files = d.files.length;
  const bits = [d.visibility === "secret" ? "secret" : "", `${files} file${files === 1 ? "" : "s"}`, d.stars ? `★ ${d.stars}` : "", d.forked_from ? "fork" : ""];
  return { label: d.title || d.files[0]?.name || d.id, description: bits.filter(Boolean).join(" · ") };
}

/** A comment's line, for the comments pick. */
export function commentLine(c: api.DropComment, now = Date.now()): { label: string; description: string; detail: string } {
  return { label: c.author, description: ago(c.created_ms, now), detail: c.body.replace(/\s+/g, " ").trim() };
}