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const { open } = Deno;type Reader = Deno.Reader;import { BufReader } from "./vendor/https/deno.land/std/io/bufio.ts";import { Buffer } from "./vendor/https/deno.land/std/io/buffer.ts";import { readAll } from "./vendor/https/deno.land/std/io/util.ts";import escape from "./vendor/https/deno.land/x/lodash/escape.js";
export interface Params {  //deno-lint-ignore no-explicit-any  [key: string]: any;}
enum ReadMode {  Normal,  Escaped,  Raw,  Comment,  Evaluate,}
enum Codes {  Begin = 60, // <  End = 62, // >  Percent = 37, // %  Escaped = 61, // =  Raw = 45, // -  Comment = 35, // #}
interface Template {  (params: Params): Promise<string>;}
const encoder = new TextEncoder();const decoder = new TextDecoder("utf-8");
class StringReader extends Buffer {  constructor(s: string) {    super(encoder.encode(s).buffer);  }}
async function include(path: string, params: Params): Promise<string> {  const result = await renderFile(path, params);  const buf = new Buffer();  await buf.readFrom(result);  return await bufToStr(buf);}
function sanitize(str: string): string {  return str.replace(/\`/g, "\\`").replace(/\$/g, "\\$").replace(/\\+$/, ""); // Trim backslashes at line end. TODO: Fix this to render backslashes.}
async function bufToStr(buf: Buffer): Promise<string> {  return decoder.decode(await readAll(buf));}
function removeLastSemi(s: string): string {  return s.trimRight().replace(/;$/, "");}
async function bufToStrWithSanitize(buf: Buffer): Promise<string> {  return sanitize(await bufToStr(buf));}
function NewTemplate(script: string): Template {  return async (params: Params): Promise<string> => {    const output: Array<string> = [];    await new Promise((resolve, reject) => {      const args = {        include,        ...params,        $$OUTPUT: output,        $$FINISHED: resolve,        $$ERROR: reject,        $$ESCAPE: escape,      };      const src = `(async() => {        try { ${script} } catch (error) { $$ERROR(error) }        $$FINISHED();      })();`;      const f = new Function(...Object.keys(args), src);      f(...Object.values(args));    });    return output.join("");  };}
export async function compile(reader: Reader): Promise<Template> {  const src = new BufReader(reader);  const buf: Array<number> = [];  const statements: Array<string> = [];  const statementBuf = new Buffer();  let readMode: ReadMode = ReadMode.Normal;  const statementBufWrite = async (byte: number): Promise<number> =>    await statementBuf.write(new Uint8Array([byte]));
  while (true) {    const byte = await src.readByte();    if (byte === null) {      break;    }
    buf.push(byte);    if (buf.length < 3) {      continue;    }
    if (readMode === ReadMode.Normal) {      // Detect ReadMode      if (buf[0] === Codes.Begin && buf[1] === Codes.Percent) {        switch (buf[2]) {          case Codes.Escaped:            readMode = ReadMode.Escaped;            break;          case Codes.Raw:            readMode = ReadMode.Raw;            break;          case Codes.Comment:            readMode = ReadMode.Comment;            break;          default:            readMode = ReadMode.Evaluate;            break;        }        statements.push(          `;$$OUTPUT.push(\`${await bufToStrWithSanitize(statementBuf)}\`);`,        );        statementBuf.reset();        buf.splice(0);        continue;      }      if (buf.length > 2) {        await statementBufWrite(buf.shift() as number);      }      continue;    }
    // Finish current ReadMode    if (buf[1] === Codes.Percent && buf[2] === Codes.End) {      statementBufWrite(buf.shift() as number);      buf.splice(0);      // Don't execute if ReadMode is Comment.      if (readMode !== ReadMode.Comment) {        switch (readMode) {          case ReadMode.Raw:            statements.push(              `;$$OUTPUT.push(${                removeLastSemi(await bufToStr(statementBuf))              });`,            );            break;          case ReadMode.Escaped:            statements.push(              `;$$OUTPUT.push($$ESCAPE(${                removeLastSemi(                  await bufToStr(statementBuf),                )              }));`,            );            break;          case ReadMode.Evaluate:            statements.push(await bufToStr(statementBuf));            break;        }      }      statementBuf.reset();      readMode = ReadMode.Normal;      continue;    }    await statementBufWrite(buf.shift() as number);  }
  // Flush buffer  while (buf.length > 0) {    await statementBufWrite(buf.shift() as number);  }  statements.push(    `$$OUTPUT.push(\`${await bufToStrWithSanitize(statementBuf)}\`);`,  );  statementBuf.reset();
  return await NewTemplate(statements.join(""));}
export async function renderToString(  body: string,  params: Params,): Promise<string> {  const reader = new StringReader(body);  const template = await compile(reader);  return template(params);}
export async function renderFileToString(  path: string,  params: Params,): Promise<string> {  const file = await open(path);  const template = await compile(file);  file.close();  return template(params);}
export async function render(body: string, params: Params): Promise<Reader> {  const result = await renderToString(body, params);  return new StringReader(result);}
export async function renderFile(  path: string,  params: Params,): Promise<Reader> {  const result = await renderFileToString(path, params);  return new StringReader(result);}