// Derived from Node.js v24.16.0 (MIT; Copyright Node.js contributors, and Joyent, Inc. and
// other Node contributors). See LICENSE-node.
// The in-memory half of Node v24's lib/internal/repl/history.js, which readline's
// Interface keeps its history in. Persisting history to a file is the REPL's business
// and is not here.
import { invalidArgType } from "../errors";
import { reverseString } from "./utils";

const kHistorySize = 30;

export interface HistoryContext {
  line: string;
  emit(event: "history", history: string[]): unknown;
}

export interface HistoryOptions {
  size?: number;
  history?: string[];
  removeHistoryDuplicates?: boolean;
}

/** Multiline entries are stored reversed, newest line first. */
const normalizeLineEndings = (line: string, from: string, to: string): string => reverseString(line, from, to);

export class ReplHistory {
  #context: HistoryContext;
  #removeHistoryDuplicates: boolean;
  #size: number;
  #history: string[];
  #index = -1;

  constructor(context: HistoryContext, options: HistoryOptions) {
    if (options.history !== undefined && !Array.isArray(options.history)) {
      throw invalidArgType("history", "an instance of Array", options.history);
    }
    if (options.size !== undefined) {
      if (typeof options.size !== "number") throw invalidArgType("size", "of type number", options.size);
      if (!(options.size >= 0)) {
        throw Object.assign(new RangeError(`The value of "size" is out of range. It must be >= 0. Received ${options.size}`), {
          code: "ERR_OUT_OF_RANGE",
        });
      }
    }
    this.#context = context;
    this.#removeHistoryDuplicates = options.removeHistoryDuplicates || false;
    this.#size = options.size ?? kHistorySize;
    this.#history = options.history ?? [];
  }

  addHistory(isMultiline: boolean, lastCommandErrored: boolean): string {
    const line = this.#context.line;
    if (line.length === 0) return "";
    if (this.#size === 0) return line;
    if (line.trim().length === 0) return line;
    // Each line of a multiline entry was saved as it was typed; keep only the whole.
    if ((isMultiline && this.#index === -1) || lastCommandErrored) this.#history.shift();
    const normalizedLine = normalizeLineEndings(line, "\n", "\r");
    if (this.#history.length === 0 || this.#history[0] !== normalizedLine) {
      if (this.#removeHistoryDuplicates) {
        const dupIndex = this.#history.indexOf(line);
        if (dupIndex !== -1) this.#history.splice(dupIndex, 1);
      }
      this.#history.unshift(normalizedLine);
      if (this.#history.length > this.#size) this.#history.pop();
    }
    this.#index = -1;
    const finalLine = isMultiline ? reverseString(this.#history[0]!) : this.#history[0]!;
    // A listener may edit the history, e.g. to drop a password before it is kept.
    this.#context.emit("history", this.#history);
    return finalLine;
  }

  canNavigateToNext(): boolean {
    return this.#index > -1 && this.#history.length > 0;
  }

  navigateToNext(substringSearch: string | null): string | null {
    if (!this.canNavigateToNext()) return null;
    const search = substringSearch || "";
    let index = this.#index - 1;
    while (index >= 0 && (!this.#history[index]!.startsWith(search) || this.#context.line === this.#history[index])) index--;
    this.#index = index;
    if (index === -1) return search;
    return normalizeLineEndings(this.#history[index]!, "\r", "\n");
  }

  canNavigateToPrevious(): boolean {
    return this.#history.length !== this.#index && this.#history.length > 0;
  }

  navigateToPrevious(substringSearch: string | null = ""): string | null {
    if (!this.canNavigateToPrevious()) return null;
    const search = substringSearch || "";
    let index = this.#index + 1;
    while (index < this.#history.length && (!this.#history[index]!.startsWith(search) || this.#context.line === this.#history[index])) {
      index++;
    }
    this.#index = index;
    if (index === this.#history.length) return search;
    return normalizeLineEndings(this.#history[index]!, "\r", "\n");
  }

  get size(): number {
    return this.#size;
  }

  get isFlushing(): boolean {
    return false;
  }

  get history(): string[] {
    return this.#history;
  }

  set history(value: string[]) {
    this.#history = value;
  }

  get index(): number {
    return this.#index;
  }

  set index(value: number) {
    this.#index = value;
  }
}