const fs = require("node:fs");
const path = require("node:path");
const { randomUUID } = require("node:crypto");

const EMPTY_DATABASE = {
  fileRecords: [],
  functionConfigs: [],
  panelInbox: [],
  identificationFiles: [],
  identificationFeedback: [],
  volumeConfigRequests: [],
  volumeConfigs: [],
  panelNotifications: [],
  userInfo: [],
  companies: [],
  productionLines: [],
  licenses: []
};

class JsonStore {
  constructor(dataDirectory) {
    this.dataDirectory = dataDirectory;
    this.filesDirectory = path.join(dataDirectory, "files");
    this.modelsDirectory = path.join(dataDirectory, "models");
    this.databasePath = path.join(dataDirectory, "database.json");
    this.writeQueue = Promise.resolve();
  }

  async initialize() {
    await fs.promises.mkdir(this.filesDirectory, { recursive: true });
    try {
      await fs.promises.access(this.databasePath);
    } catch {
      await this.writeDatabase(structuredClone(EMPTY_DATABASE));
    }
  }

  async read() {
    const content = await fs.promises.readFile(this.databasePath, "utf8");
    return { ...structuredClone(EMPTY_DATABASE), ...JSON.parse(content) };
  }

  async update(mutator) {
    const operation = this.writeQueue.then(async () => {
      const database = await this.read();
      const result = await mutator(database);
      await this.writeDatabase(database);
      return result;
    });
    this.writeQueue = operation.catch(() => undefined);
    return operation;
  }

  async writeDatabase(database) {
    await fs.promises.mkdir(this.dataDirectory, { recursive: true });
    const temporaryPath = `${this.databasePath}.${process.pid}.tmp`;
    await fs.promises.writeFile(
      temporaryPath,
      `${JSON.stringify(database, null, 2)}\n`,
      "utf8"
    );
    await fs.promises.rename(temporaryPath, this.databasePath);
  }

  createId(prefix) {
    return `${prefix}_${randomUUID()}`;
  }

  resolveStoredFile(fileID) {
    if (typeof fileID !== "string") return null;
    const isModel = fileID.startsWith("model://");
    if (!isModel && !fileID.startsWith("local://")) return null;
    const rootDirectory = isModel ? this.modelsDirectory : this.filesDirectory;
    const relativePath = fileID.slice(isModel ? "model://".length : "local://".length).replace(/\\/g, "/");
    const absolutePath = path.resolve(rootDirectory, relativePath);
    const relativeToRoot = path.relative(rootDirectory, absolutePath);
    if (relativeToRoot.startsWith("..") || path.isAbsolute(relativeToRoot)) return null;
    return absolutePath;
  }
}

module.exports = { EMPTY_DATABASE, JsonStore };