import { shallowRef } from "vue";
import type { NativeTransaction, NativeViewEntry } from "../types";

export class NativeHistoryLedger {
  readonly keys = shallowRef<string[]>([]);

  get length() {
    return this.keys.value.length;
  }

  get previousKey() {
    return this.keys.value.at(-2);
  }

  initialize(key: string) {
    this.keys.value = [key];
  }

  contains(key: string) {
    return this.keys.value.includes(key);
  }

  indexOf(key: string) {
    return this.keys.value.lastIndexOf(key);
  }

  accept(target: NativeViewEntry, transaction: NativeTransaction | null) {
    const history = this.keys.value;
    if (!history.length) return this.initialize(target.key);

    if (
      transaction?.kind === "pop" ||
      transaction?.kind === "dismiss" ||
      transaction?.replace
    ) {
      const targetIndex = history.lastIndexOf(target.key);
      this.keys.value =
        targetIndex >= 0
          ? history.slice(0, targetIndex + 1)
          : [...history.slice(0, -1), target.key];
      return;
    }

    const existingIndex = history.lastIndexOf(target.key);
    this.keys.value = transaction
      ? [...history, target.key]
      : existingIndex >= 0
        ? history.slice(0, existingIndex + 1)
        : [...history, target.key];
  }
}