export async function runBrowserOpfsParameterSections(context, simulator) {
  const {
    expectErrorContaining,
    expectEvent,
    expectIncludes,
    expectLinuxCncParameterScratchMissing,
    expectMissingOpfsFile,
    expectMissingWasmPath,
    expectNoEvent,
    expectOpfsDirectoryStat,
    expectText,
    expectWasmFilesMissing,
    near,
    readOpfsText,
    readWasmText,
    removeWasmPathIfExists,
    runSection,
    withSmokeSimulator,
  } = context;
  const backend = { backend: "linuxcnc-rs274" };
  const parseWithParameters = (program, path) => simulator.parseWithParameterFile(program, path, "linuxcnc", backend);
  const g28BranchProgram = "G21 G90\nF100\nO10 if [#5161 EQ 1]\nG1 X9\nO10 endif\n";
  const writeDefaultScratch = (main, temporary, backup) => {
    simulator.fs.module.FS.writeFile("rs274ngc.var", main);
    simulator.fs.module.FS.writeFile("rs274ngc.var.new", temporary);
    simulator.fs.module.FS.writeFile("rs274ngc.var.bak", backup);
  };

  await runSection("opfs parameter save", async () => {
    await simulator.parseWithParameterFile("G21 G90\nG0 X1\nG28.1\nM30\n", "parameters/rs274ngc.var", "linuxcnc", backend);
    const opfsParameterFile = await readOpfsText(simulator, "parameters/rs274ngc.var");
    expectIncludes(opfsParameterFile, "5161\t1.000000", "LinuxCNC parameter file was not persisted into OPFS");
    expectWasmFilesMissing(simulator.fs.module.FS, ["rs274ngc.var", "rs274ngc.var.new", "rs274ngc.var.bak"], (parameterPath) => `LinuxCNC parameter scratch file remained outside OPFS after save: ${parameterPath}`);
  });

  await runSection("opfs parameter restore in new instance", async () => {
    await withSmokeSimulator(async (restoredWorkspaceSimulator) => {
      // LinuxCNC source basis: rs274ngc_pre.cc restore_parameters()
      // loads persisted numbered parameters before interpreting blocks.
      const restoredWorkspaceEvents = await restoredWorkspaceSimulator.parseWithParameterFile(
        "G21 G90\nF100\nO10 if [#5161 EQ 1]\nG1 X8\nO10 endif\n",
        "parameters/rs274ngc.var",
        "linuxcnc",
        backend,
      );
      expectEvent(restoredWorkspaceEvents, (event) => event.type === "linear-feed" && near(event.end.x, 8),
        "LinuxCNC OPFS parameter file was not restored across WASM simulator instances");
    });
  });

  await runSection("opfs default parameter backup", async () => {
    // LinuxCNC source basis: rs274ngc_pre.cc save_parameters()
    // preserves the previous default parameter file as filename + ".bak".
    await parseWithParameters("G21 G90\nM30\n", "parameters/rs274ngc.var");
    const defaultParameterBackup = await readOpfsText(simulator, "parameters/rs274ngc.var.bak");
    expectIncludes(defaultParameterBackup, "5161\t1.000000", "LinuxCNC default OPFS parameter backup did not preserve the previous file");
  });

  await runSection("opfs parameter temporary cleanup", async () => {
    await simulator.fs.opfs.writeFile("parameters/rs274ngc.var.new", "stale temporary parameter file\n");
    // LinuxCNC source basis: rs274ngc_pre.cc save_parameters() writes
    // filename + ".new", then renames it over the parameter file.
    simulator.fs.module.FS.writeFile("rs274ngc.var.new", "stale wasm temporary parameter file\n");
    const restoredParameterEvents = await parseWithParameters(
      "G21 G90\nF100\nO10 if [#5161 EQ 1]\nG1 X9\nO10 endif\n",
      "parameters/rs274ngc.var",
    );
    expectEvent(restoredParameterEvents, (event) => event.type === "linear-feed" && near(event.end.x, 9),
      "LinuxCNC parameter file was not restored from OPFS");
    await expectMissingOpfsFile(
      () => simulator.fs.opfs.readFile("parameters/rs274ngc.var.new"),
      "stale LinuxCNC temporary parameter file remained in OPFS",
    );
    expectMissingWasmPath(
      () => simulator.fs.module.FS.readFile("rs274ngc.var.new"),
      "stale LinuxCNC temporary parameter file remained in WASM FS",
    );
    simulator.fs.module.FS.mkdir(simulator.fs.opfs.resolvePath("parameters/new-directory.var.new")); await simulator.fs.opfs.persistDirectory("parameters/new-directory.var.new");
    await parseWithParameters("G21 G90\nG0 X5\nG28.1\nM30\n", "parameters/new-directory.var");
    expectIncludes(await readOpfsText(simulator, "parameters/new-directory.var"), "5161\t5.000000", "LinuxCNC OPFS parameter file was not saved when stale temporary cleanup saw a directory");
    await expectOpfsDirectoryStat(simulator, "parameters/new-directory.var.new", "LinuxCNC temporary file cleanup removed an existing OPFS directory"); await simulator.fs.opfs.removeDirectory("parameters/new-directory.var.new");
  });

  await runSection("opfs parameter backup bridge", async () => {
    // LinuxCNC source basis: rs274ngc_pre.cc save_parameters()
    // attempts link(filename, filename + ".bak") but treats link
    // failure as non-fatal. The browser bridge must persist a backup
    // when the WASM filesystem exposes one.
    simulator.fs.module.FS.writeFile("rs274ngc.var", "5161\t2.000000\n");
    simulator.fs.module.FS.writeFile("rs274ngc.var.bak", "5161\t1.000000\n");
    await simulator.fs.opfs.persistParameterFile("parameters/backup-bridge.var");
    const opfsParameterBackup = await readOpfsText(simulator, "parameters/backup-bridge.var.bak");
    expectIncludes(opfsParameterBackup, "5161\t1.000000",
      "LinuxCNC parameter backup file was not bridged into OPFS");
    expectWasmFilesMissing(simulator.fs.module.FS, ["rs274ngc.var", "rs274ngc.var.new", "rs274ngc.var.bak"], (parameterPath) => `LinuxCNC parameter scratch file remained outside OPFS after backup bridge: ${parameterPath}`);
  });

  await runSection("opfs parameter backup after existing save", async () => {
    await simulator.fs.opfs.writeFile("parameters/existing-save.var", "5161\t3.000000\n");
    await simulator.fs.opfs.writeFile("parameters/existing-save.var.bak", "stale previous backup\n");
    // LinuxCNC source basis: rs274ngc_pre.cc save_parameters() unlinks
    // filename + ".bak", links the current parameter file to it,
    // then renames filename + ".new" over filename.
    await parseWithParameters("G21 G90\nG0 X4\nG28.1\nM30\n", "parameters/existing-save.var");
    await withSmokeSimulator(async (restoredBackupSimulator) => {
      expectIncludes(await readOpfsText(restoredBackupSimulator, "parameters/existing-save.var"), "5161\t4.000000", "LinuxCNC existing OPFS parameter file was not restored in a new WASM instance");
      expectIncludes(await readOpfsText(restoredBackupSimulator, "parameters/existing-save.var.bak"), "5161\t3.000000", "LinuxCNC existing OPFS parameter backup was not restored in a new WASM instance");
    });
    await expectMissingOpfsFile(
      () => simulator.fs.opfs.readFile("parameters/existing-save.var.new"),
      "LinuxCNC existing OPFS parameter temporary file remained after save",
    );
    await simulator.fs.opfs.writeFile("parameters/backup-directory.var", "5161\t6.000000\n");
    const backupDirectory = simulator.fs.opfs.resolvePath("parameters/backup-directory.var.bak");
    simulator.fs.module.FS.mkdir(backupDirectory);
    await simulator.fs.opfs.persistDirectory("parameters/backup-directory.var.bak");
    await parseWithParameters("G21 G90\nG0 X7\nG28.1\nM30\n", "parameters/backup-directory.var");
    expectIncludes(await readOpfsText(simulator, "parameters/backup-directory.var"), "5161\t7.000000",
      "LinuxCNC OPFS parameter file was not saved when backup link failed");
    await expectOpfsDirectoryStat(simulator, "parameters/backup-directory.var.bak",
      "LinuxCNC non-fatal OPFS backup failure did not leave the existing backup path intact");
  });

  await runSection("opfs parameter stale backup cleanup", async () => {
    await simulator.fs.opfs.removeFile("parameters/stale-backup-cleanup.var");
    await simulator.fs.opfs.removeFile("parameters/stale-backup-cleanup.var.new");
    await simulator.fs.opfs.removeFile("parameters/stale-backup-cleanup.var.bak");
    await simulator.fs.opfs.writeFile("parameters/stale-backup-cleanup.var.bak", "stale backup without main file\n");
    removeWasmPathIfExists(simulator, "rs274ngc.var.bak");
    removeWasmPathIfExists(simulator, "/rs274ngc.var.bak");
    await simulator.parseWithParameterFile(
      "G21 G90\nM30\n",
      "parameters/stale-backup-cleanup.var",
      "linuxcnc",
      backend,
    );
    await expectMissingOpfsFile(
      () => simulator.fs.opfs.readFile("parameters/stale-backup-cleanup.var.bak"),
      "stale LinuxCNC parameter backup file remained in OPFS",
    );
    // LinuxCNC source basis: rs274ngc_pre.cc save_parameters()
    // unlinks stale backup files before replacing the parameter file.
    await simulator.fs.opfs.removeFile("parameters/missing-cleanup/rs274ngc.var.bak");
  });

  await runSection("opfs program file with parameter persistence", async () => {
    await simulator.fs.opfs.writeFile("programs/parameter-file-smoke.ngc", "G21 G90\nF100\nG0 X1\nG28.1\nM30\n");
    const fileParameterEvents = await simulator.parseFileWithParameterFile(
      "programs/parameter-file-smoke.ngc",
      "parameters/rs274ngc.var",
      "linuxcnc",
      backend,
    );
    expectEvent(fileParameterEvents, (event) => event.type === "program-end", "OPFS program file with LinuxCNC parameter persistence did not parse");
    await withSmokeSimulator(async (restoredFileParameterSimulator) => expectEvent(await restoredFileParameterSimulator.parseWithParameterFile("G21 G90\nF100\nO10 if [#5161 EQ 1]\nG1 X10\nO10 endif\n", "parameters/rs274ngc.var", "linuxcnc", backend), (event) => event.type === "linear-feed" && near(event.end.x, 10), "LinuxCNC OPFS parameter file saved by parseFileWithParameterFile was not restored in a new WASM instance"));
  });

  await runSection("opfs missing parameter file creation", async () => {
    await simulator.fs.opfs.removeFile("parameters/missing-main.var");
    await simulator.fs.opfs.removeFile("parameters/missing-main.var.new");
    await simulator.fs.opfs.removeFile("parameters/missing-main.var.bak");
    await simulator.fs.opfs.writeFile("parameters/missing-main.var.bak", "stale backup without main file\n");
    await simulator.fs.opfs.writeFile("parameters/missing-main.var.new", "stale temporary without main file\n");
    // LinuxCNC source basis: rs274ngc_pre.cc save_parameters() unlinks
    // filename + RS274NGC_PARAMETER_FILE_BACKUP_SUFFIX before linking,
    // then renames filename + ".new" over the parameter file.
    simulator.fs.module.FS.writeFile("rs274ngc.var.bak", "stale wasm backup without main file\n");
    simulator.fs.module.FS.writeFile("rs274ngc.var.new", "stale wasm temporary without main file\n");
    await simulator.parseWithParameterFile(
      "G21 G90\nM30\n",
      "parameters/missing-main.var",
      "linuxcnc",
      backend,
    );
    const missingMainParameterFile = await readOpfsText(simulator, "parameters/missing-main.var");
    expectIncludes(missingMainParameterFile, "5220\t1.000000",
      "LinuxCNC missing parameter file was not created through OPFS");
    expectIncludes(missingMainParameterFile, "5161\t0.000000",
      "LinuxCNC missing parameter file did not include required G28 parameter");
    await expectMissingOpfsFile(
      () => simulator.fs.opfs.readFile("parameters/missing-main.var.bak"),
      "stale LinuxCNC missing-parameter backup remained in OPFS after first creation",
    );
    const missingMainRestoreEvents = await simulator.parseWithParameterFile(
      "G21 G90\nF100\nO10 if [#5220 EQ 1]\nG1 X6\nO10 endif\n",
      "parameters/missing-main.var",
      "linuxcnc",
      backend,
    );
    expectEvent(missingMainRestoreEvents, (event) => event.type === "linear-feed" && near(event.end.x, 6),
      "LinuxCNC-created missing OPFS parameter file was not restored on the next parse");
    const missingMainParameterBackup = await readOpfsText(simulator, "parameters/missing-main.var.bak");
    expectIncludes(missingMainParameterBackup, "5220\t1.000000",
      "LinuxCNC-created OPFS parameter file was not backed up on the next successful save");
    expectMissingWasmPath(
      () => simulator.fs.module.FS.readFile("rs274ngc.var.bak"),
      "stale LinuxCNC missing-parameter backup remained in WASM FS",
    );
    await expectMissingOpfsFile(
      () => simulator.fs.opfs.readFile("parameters/missing-main.var.new"),
      "stale LinuxCNC missing-parameter temporary file remained in OPFS",
    );
    expectMissingWasmPath(
      () => simulator.fs.module.FS.readFile("rs274ngc.var.new"),
      "stale LinuxCNC missing-parameter temporary file remained in WASM FS",
    );
  });

  await runSection("opfs invalid parameter restore failures", async () => {
    await simulator.fs.opfs.writeFile("parameters/out-of-order.var", "5162\t1.000000\n5161\t1.000000\n");
    await expectErrorContaining(
      () => simulator.parseWithParameterFile(
        "G21 G90\nM30\n",
        "parameters/out-of-order.var",
        "linuxcnc",
        backend,
      ),
      "Parameter file out of order",
      "LinuxCNC accepted an out-of-order OPFS parameter file",
    );
    const outOfOrderParameterFile = await readOpfsText(simulator, "parameters/out-of-order.var");
    expectText(outOfOrderParameterFile, "5162\t1.000000\n5161\t1.000000\n",
      "LinuxCNC persisted an out-of-order OPFS parameter file after restore failure");
    expectMissingWasmPath(
      () => simulator.fs.module.FS.readFile("rs274ngc.var"),
      "LinuxCNC out-of-order parameter file remained in WASM FS after restore failure",
    );
    await simulator.fs.opfs.writeFile("parameters/out-of-range.var", "0\t1.000000\n");
    await expectErrorContaining(
      () => simulator.parseWithParameterFile(
        "G21 G90\nM30\n",
        "parameters/out-of-range.var",
        "linuxcnc",
        backend,
      ),
      "Parameter number out of range",
      "LinuxCNC accepted an out-of-range OPFS parameter file",
    );
    const outOfRangeParameterFile = await readOpfsText(simulator, "parameters/out-of-range.var");
    expectText(outOfRangeParameterFile, "0\t1.000000\n",
      "LinuxCNC persisted an out-of-range OPFS parameter file after restore failure");
    expectMissingWasmPath(
      () => simulator.fs.module.FS.readFile("rs274ngc.var"),
      "LinuxCNC out-of-range parameter file remained in WASM FS after restore failure",
    );
    await simulator.fs.opfs.writeFile("parameters/failed-parse.var", "1\t0.000000\n");
    await expectErrorContaining(
      () => simulator.parseWithParameterFile(
        "G21 G90\nG28.1\n#0 = 1\n",
        "parameters/failed-parse.var",
        "linuxcnc",
        backend,
      ),
      "",
      "LinuxCNC accepted a failing parse that should not persist parameters",
    );
    const failedParseParameterFile = await readOpfsText(simulator, "parameters/failed-parse.var");
    if (failedParseParameterFile.includes("5161\t1.000000")) {
      throw new Error("LinuxCNC persisted failed parse parameter updates into OPFS");
    }
    // LinuxCNC source basis: save_parameters() runs only after successful interpretation.
    await simulator.fs.opfs.writeFile("parameters/failed-backup.var", "5161\t5.000000\n");
    await simulator.fs.opfs.writeFile("parameters/failed-backup.var.bak", "5161\t4.000000\n");
    await expectErrorContaining(
      () => simulator.parseWithParameterFile("G21 G90\n#0 = 1\n", "parameters/failed-backup.var", "linuxcnc", backend),
      "",
      "LinuxCNC accepted a failing parse that should not replace the parameter backup",
    );
    expectText(await readOpfsText(simulator, "parameters/failed-backup.var.bak"), "5161\t4.000000\n", "LinuxCNC replaced the OPFS parameter backup after a failed parse");
  });

  await runSection("opfs stale parameter state cleanup", async () => {
    await simulator.fs.opfs.writeFile("parameters/stale-state.var", "5161\t1.000000\n");
    const staleStateEvents = await simulator.parseWithParameterFile(g28BranchProgram, "parameters/stale-state.var", "linuxcnc", backend);
    expectEvent(staleStateEvents, (event) => event.type === "linear-feed" && near(event.end.x, 9), "LinuxCNC did not honor the loaded OPFS parameter state");
    await simulator.fs.opfs.removeFile("parameters/stale-state.var");
    const missingStateEvents = await simulator.parseWithParameterFile(g28BranchProgram, "parameters/stale-state.var", "linuxcnc", backend);
    expectNoEvent(missingStateEvents, (event) => event.type === "linear-feed" && near(event.end.x, 9), "LinuxCNC stale OPFS parameter state was not cleared when the file was missing");
    // LinuxCNC source basis: rs274ngc_pre.cc restore_parameters() ignores
    // missing files and reads only the configured parameter file.
    writeDefaultScratch("5161\t1.000000\n", "stale temporary parameter file\n", "stale backup parameter file\n");
    const missingLoad = await simulator.fs.opfs.loadParameterFile("parameters/load-missing.var");
    if (missingLoad !== null) {
      throw new Error("missing OPFS parameter file did not return null");
    }
    expectLinuxCncParameterScratchMissing(simulator, (parameterPath) => `missing OPFS parameter load left stale WASM file ${parameterPath}`);
    writeDefaultScratch("5161\t7.000000\n", "stale successful-load temporary parameter file\n", "stale successful-load backup parameter file\n");
    await simulator.fs.opfs.writeFile("parameters/load-existing.var", "5161\t2.000000\n");
    await simulator.fs.opfs.loadParameterFile("parameters/load-existing.var");
    expectText(readWasmText(simulator, "rs274ngc.var"), "5161\t2.000000\n", "existing OPFS parameter load did not replace the LinuxCNC default parameter file");
    expectWasmFilesMissing(simulator.fs.module.FS, ["rs274ngc.var.new", "rs274ngc.var.bak"], (parameterPath) => `existing OPFS parameter load left stale WASM file ${parameterPath}`);
  });
}