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, "docs/BLENDER_WEB_PARITY_TASK_PLAN_V2.json");
const outputDir = path.join(root, "tests/golden/WBV2");
const catalogPath = path.join(outputDir, "task-catalog.jsonl");
const indexPath = path.join(outputDir, "task-index.json");
const planBytes = fs.readFileSync(planPath);
const plan = JSON.parse(planBytes);
const sha256 = (bytes) => crypto.createHash("sha256").update(bytes).digest("hex");
const relative = (file) => path.relative(root, file).replaceAll(path.sep, "/");

const active = plan.tasks.filter((task) => task.ready === true && task.status === "in_progress");
if (active.length !== 1) throw new Error(`V2 plan must have exactly one ready in_progress task; found ${active.length}`);

const lines = [];
const entries = {};
let offset = 0;
for (let index = 0; index < plan.tasks.length; index += 1) {
  const task = plan.tasks[index];
  const compact = {
    id: task.id,
    gapId: task.parityId ?? `workflow:${task.title}`,
    ownerFamily: task.owner,
    sourceTask: task.phase,
    state: task.status === "done" ? "completed" : task.ready === true ? "active" : "pending",
    targetImplementationClass: task.implementationClass,
    exitCriteria: task.acceptance,
  };
  const line = `${JSON.stringify(compact)}\n`;
  const length = Buffer.byteLength(line);
  lines.push(line);
  entries[task.id] = {
    line: index,
    offset,
    length,
    previous: task.dependsOn.at(-1) ?? null,
    next: plan.tasks[index + 1]?.id ?? null,
  };
  offset += length;
}

fs.mkdirSync(outputDir, { recursive: true });
const catalogBytes = Buffer.from(lines.join(""));
fs.writeFileSync(catalogPath, catalogBytes);
const index = {
  schemaVersion: 1,
  operation: "BLENDER_WEB_CAPABILITY_TASK_INDEX",
  source: { path: relative(planPath), sha256: sha256(planBytes) },
  catalog: { path: relative(catalogPath), sha256: sha256(catalogBytes) },
  taskCount: plan.tasks.length,
  activeTask: active[0].id,
  entries,
};
fs.writeFileSync(indexPath, `${JSON.stringify(index)}\n`);
process.stdout.write(`v2-task-index-generated tasks=${plan.tasks.length} active=${index.activeTask} output=${relative(indexPath)}\n`);