import crypto from "node:crypto";
import fs from "node:fs";
import path from "node:path";
import { fileURLToPath } from "node:url";

const root = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "../..");
const planPath = path.join(root, "tests/golden/M15-03A/next-task-plan.json");
const outputDir = path.join(root, "tests/golden/M15-03A");
const catalogPath = path.join(outputDir, "task-catalog.jsonl");
const indexPath = path.join(outputDir, "task-index.json");
const sha256 = (bytes) => crypto.createHash("sha256").update(bytes).digest("hex");
const relative = (file) => path.relative(root, file).replaceAll(path.sep, "/");

const planBytes = fs.readFileSync(planPath);
const plan = JSON.parse(planBytes);
if (!Array.isArray(plan.tasks) || plan.tasks.length === 0) throw new Error("next-task plan has no tasks");

fs.mkdirSync(outputDir, { recursive: true });
const lines = [];
const entries = {};
let offset = 0;
for (let index = 0; index < plan.tasks.length; index += 1) {
  const task = plan.tasks[index];
  const compactTask = {
    id: task.id,
    gapId: task.gapId,
    ownerFamily: task.ownerFamily,
    sourceTask: task.sourceTask,
    state: task.state,
    targetImplementationClass: task.targetImplementationClass,
  };
  const line = `${JSON.stringify(compactTask)}\n`;
  const length = Buffer.byteLength(line, "utf8");
  lines.push(line);
  entries[task.id] = {
    line: index,
    offset,
    length,
    previous: plan.tasks[index - 1]?.id ?? null,
    next: plan.tasks[index + 1]?.id ?? null,
  };
  offset += length;
}
const catalogBytes = Buffer.from(lines.join(""), "utf8");
fs.writeFileSync(catalogPath, catalogBytes);
const index = {
  schemaVersion: 1,
  operation: "BLENDER_TASK_CONTEXT_INDEX",
  source: { path: relative(planPath), sha256: sha256(planBytes) },
  catalog: { path: relative(catalogPath), sha256: sha256(catalogBytes) },
  taskCount: plan.tasks.length,
  activeTask: plan.firstTask,
  entries,
};
fs.writeFileSync(indexPath, `${JSON.stringify(index)}\n`);
process.stdout.write(`task-index-generated tasks=${plan.tasks.length} catalogBytes=${catalogBytes.byteLength} output=${relative(indexPath)}\n`);