"use strict";

const crypto = require("node:crypto");
const fs = require("node:fs");
const path = require("node:path");
const { atomicWriteJson } = require("../storage/atomicFile");
const { loadGuidanceDocuments } = require("./guidanceDocuments");

const LICENSE_NAME = "CH-J Proprietary Software License";
const LICENSE_VERSION = "1.14";

class LicenseAcceptance {
  constructor({ storageRoot, licensePath, appVersion, buildId, docsRoot = path.resolve(__dirname, "../../../docs") }) {
    this.filePath = path.join(storageRoot, "legal", "license-acceptance.json");
    this.text = fs.readFileSync(licensePath, "utf8");
    if (!/^CH-J\s+Proprietary Software License\s*\n\s*Version 1\.14\b/.test(this.text) ||
        this.text.length < 10000 || !this.text.trimEnd().endsWith("End of License.")) {
      throw new Error("The complete CH-J application license 1.14 is required.");
    }
    const guidance = loadGuidanceDocuments(docsRoot);
    this.guidance = guidance.documents;
    this.identity = Object.freeze({
      license: LICENSE_NAME, licenseVersion: LICENSE_VERSION,
      sha256: crypto.createHash("sha256").update(this.text).digest("hex"),
      appVersion, buildId, guidanceSha256: guidance.sha256
    });
  }

  isAccepted() {
    try {
      const record = JSON.parse(fs.readFileSync(this.filePath, "utf8"));
      return record.schemaVersion === 1 && record.accepted === true && record.guidanceDisplayed === true &&
        typeof record.acceptedAt === "string" && Number.isFinite(Date.parse(record.acceptedAt)) &&
        Object.entries(this.identity).every(([key, value]) => record[key] === value);
    } catch { return false; }
  }

  accept(payload) {
    if (payload?.accepted !== true || payload?.sha256 !== this.identity.sha256 ||
        payload?.guidanceShown !== true || payload?.guidanceSha256 !== this.identity.guidanceSha256) {
      throw new Error("Explicit acceptance of the displayed license is required.");
    }
    atomicWriteJson(this.filePath, {
      schemaVersion: 1, ...this.identity, accepted: true, guidanceDisplayed: true, acceptedAt: new Date().toISOString()
    });
  }
}

module.exports = { LicenseAcceptance, LICENSE_NAME, LICENSE_VERSION };