// Derived from `ansi-escapes` (MIT, Sindre Sorhus), reduced to the escapes Ink uses.
// Control characters and sequence introducers. This module is the single
// home for escape sequences: everything else imports these instead of
// spelling out `\u001B[...` inline.
export const ESC = "\u001B";
export const BEL = "\u0007";
export const DEL = "\u007F";
/** Control Sequence Introducer. */
export const CSI = `${ESC}[`;
/** Operating System Command. */
export const OSC = `${ESC}]`;
/** String Terminator. */
export const ST = `${ESC}\\`;
/** Single-byte C1 forms of CSI and ST. */
export const C1_CSI = "\u009B";
export const C1_ST = "\u009C";

const sep = ";";

export const cursorTo = (x: number, y?: number): string => {
  if (typeof y !== "number") {
    return CSI + (x + 1) + "G";
  }

  return CSI + (y + 1) + sep + (x + 1) + "H";
};

export const cursorUp = (count = 1): string => CSI + count + "A";
export const cursorDown = (count = 1): string => CSI + count + "B";
export const cursorLeft = CSI + "G";
export const cursorNextLine = CSI + "E";

export const eraseEndLine = CSI + "K";
export const eraseLine = CSI + "2K";
export const eraseScreen = CSI + "2J";

export const eraseLines = (count: number): string => {
  let clear = "";

  for (let i = 0; i < count; i++) {
    clear += eraseLine + (i < count - 1 ? cursorUp() : "");
  }

  if (count) {
    clear += cursorLeft;
  }

  return clear;
};

// 1. Erases the screen (only done in case `2` is not supported)
// 2. Erases the whole screen including scrollback buffer
// 3. Moves cursor to the top-left position
export const clearTerminal = `${eraseScreen}${CSI}3J${CSI}H`;

export const enterAlternativeScreen = CSI + "?1049h";
export const exitAlternativeScreen = CSI + "?1049l";

export const cursorShow = CSI + "?25h";
export const cursorHide = CSI + "?25l";
export type CursorShape = "block" | "underline" | "bar";
export const cursorShape = (shape: CursorShape, blinking = true): string => {
  const value = {
    block: blinking ? 1 : 2,
    underline: blinking ? 3 : 4,
    bar: blinking ? 5 : 6,
  }[shape];
  return `${CSI}${value} q`;
};
export const cursorColor = (color: string): string => `${OSC}12;${color}${BEL}`;
export const resetCursorColor = `${OSC}112${BEL}`;

export const enableBracketedPaste = CSI + "?2004h";
export const disableBracketedPaste = CSI + "?2004l";

// Markers the terminal wraps around pasted input while bracketed paste is on.
export const pasteStart = CSI + "200~";
export const pasteEnd = CSI + "201~";

// Synchronized update mode (DEC mode 2026): begin / end synchronized update.
export const bsu = CSI + "?2026h";
export const esu = CSI + "?2026l";

// Kitty keyboard protocol: query support, push a flag set, pop it off.
export const kittyQuery = CSI + "?u";
export const pushKittyKeyboard = (flags: number): string => `${CSI}>${flags}u`;
export const popKittyKeyboard = CSI + "<u";

export const link = (text: string, url: string): string =>
  [OSC, "8", sep, sep, url, BEL, text, OSC, "8", sep, sep, BEL].join("");

export const ansiEscapes = {
  cursorTo,
  cursorUp,
  cursorDown,
  cursorLeft,
  cursorNextLine,
  eraseEndLine,
  eraseLine,
  eraseScreen,
  eraseLines,
  clearTerminal,
  enterAlternativeScreen,
  exitAlternativeScreen,
  cursorShow,
  cursorHide,
  cursorShape,
  cursorColor,
  resetCursorColor,
  enableBracketedPaste,
  disableBracketedPaste,
  pasteStart,
  pasteEnd,
  bsu,
  esu,
  kittyQuery,
  pushKittyKeyboard,
  popKittyKeyboard,
  link,
};