/**
 * applyOps – execute a fenced ```ops``` block returned by Jess.
 * Supports milestones, tasks, impacts, scenario utilities, and college profile.
 *
 * @param {object}  opsObj      – parsed JSON inside ```ops```
 * @param {object}  req         – Express request (for auth header)
 * @param {string}  scenarioId  – current career_profile_id (optional but lets us
 *                                auto-fill when the bot forgets)
 * @return {string[]}           – human-readable confirmations
 */
export async function applyOps(opsObj = {}, req, scenarioId = null) {
  if (!Array.isArray(opsObj?.milestones) && !Array.isArray(opsObj?.tasks)
      && !Array.isArray(opsObj?.impacts)   && !Array.isArray(opsObj?.scenarios)
      && !opsObj.collegeProfile) return [];

  const apiBase  = process.env.APTIVA_INTERNAL_API || 'http://localhost:5002/api';
  const auth     = (p, o = {}) =>
    internalFetch(req, `${apiBase}${p}`, {
      headers: { 'Content-Type': 'application/json', ...(o.headers || {}) },
      ...o
    });

  const confirmations = [];

  /* ────────────────────────────────────────────────────
     1. MILESTONE-LEVEL OPS  (unchanged behaviour)
     ──────────────────────────────────────────────────── */
  for (const m of opsObj.milestones || []) {
    const op = (m?.op || '').toUpperCase();

    if (op === 'DELETE' && m.id) {                    // single-scenario delete
      const r = await auth(`/premium/milestones/${m.id.trim()}`, { method: 'DELETE' });
      if (r.ok) confirmations.push(`Deleted milestone ${m.id}`);
      continue;
    }

    if (op === 'UPDATE' && m.id && m.patch) {
      const r = await auth(`/premium/milestones/${m.id}`, {
        method: 'PUT', body: JSON.stringify(m.patch)
      });
      if (r.ok) confirmations.push(`Updated milestone ${m.id}`);
      continue;
    }

    if (op === 'CREATE' && m.data) {
      m.data.career_profile_id = m.data.career_profile_id || scenarioId;
      const r = await auth('/premium/milestone', { method: 'POST', body: JSON.stringify(m.data) });
      if (r.ok) {
        const j = await r.json();
        const newId = Array.isArray(j) ? j[0]?.id : j.id;
        confirmations.push(`Created milestone ${newId || '(new)'}`);
      }
      continue;
    }

    if (op === 'DELETEALL' && m.id) {                 // delete across every scenario
      const r = await auth(`/premium/milestones/${m.id}/all`, { method: 'DELETE' });
      if (r.ok) confirmations.push(`Deleted milestone ${m.id} from all scenarios`);
      continue;
    }

    if (op === 'COPY' && m.id && Array.isArray(m.targetScenarioIds)) {
      const r = await auth('/premium/milestone/copy', {
        method: 'POST',
        body  : JSON.stringify({ milestoneId: m.id, scenarioIds: m.targetScenarioIds })
      });
      if (r.ok) confirmations.push(`Copied milestone ${m.id} → ${m.targetScenarioIds.length} scenario(s)`);
      continue;
    }
  }

  /* ────────────────────────────────────────────────────
     2. TASK-LEVEL OPS
     ──────────────────────────────────────────────────── */
  for (const t of opsObj.tasks || []) {
    const op = (t?.op || '').toUpperCase();

    if (op === 'CREATE' && t.data && t.data.milestone_id) {
      await auth('/premium/tasks', { method: 'POST', body: JSON.stringify(t.data) });
      confirmations.push(`Added task to milestone ${t.data.milestone_id}`);
      continue;
    }

    if (op === 'UPDATE' && t.taskId && t.patch) {
      await auth(`/premium/tasks/${t.taskId}`, { method: 'PUT', body: JSON.stringify(t.patch) });
      confirmations.push(`Updated task ${t.taskId}`);
      continue;
    }

    if (op === 'DELETE' && t.taskId) {
      await auth(`/premium/tasks/${t.taskId}`, { method: 'DELETE' });
      confirmations.push(`Deleted task ${t.taskId}`);
      continue;
    }
  }

  /* ────────────────────────────────────────────────────
     3. IMPACT-LEVEL OPS
     ──────────────────────────────────────────────────── */
  for (const imp of opsObj.impacts || []) {
    const op = (imp?.op || '').toUpperCase();

    if (op === 'CREATE' && imp.data && imp.data.milestone_id) {
      await auth('/premium/milestone-impacts', { method: 'POST', body: JSON.stringify(imp.data) });
      confirmations.push(`Added impact to milestone ${imp.data.milestone_id}`);
      continue;
    }

    if (op === 'UPDATE' && imp.impactId && imp.patch) {
      await auth(`/premium/milestone-impacts/${imp.impactId}`, { method: 'PUT', body: JSON.stringify(imp.patch) });
      confirmations.push(`Updated impact ${imp.impactId}`);
      continue;
    }

    if (op === 'DELETE' && imp.impactId) {
      await auth(`/premium/milestone-impacts/${imp.impactId}`, { method: 'DELETE' });
      confirmations.push(`Deleted impact ${imp.impactId}`);
      continue;
    }
  }

  /* ────────────────────────────────────────────────────
     4. SCENARIO (career_profile) OPS
     ──────────────────────────────────────────────────── */
  for (const s of opsObj.scenarios || []) {
    const op = (s?.op || '').toUpperCase();

    if (op === 'CREATE' && s.data?.career_name) {
      await auth('/premium/career-profile', { method: 'POST', body: JSON.stringify(s.data) });
      confirmations.push(`Created scenario “${s.data.career_name}”`);
      continue;
    }

    if (op === 'UPDATE' && s.scenarioId && s.patch) {
      /* if only goals are patched, hit the goals route; otherwise create a PUT route */
      const hasOnlyGoals = Object.keys(s.patch).length === 1 && s.patch.career_goals !== undefined;
      const url = hasOnlyGoals
        ? `/premium/career-profile/${s.scenarioId}/goals`
        : `/premium/career-profile`;          // <-- add generic PATCH if you implemented one
      await auth(url.replace(/\/$/, `/${s.scenarioId}`), { method: 'PUT', body: JSON.stringify(s.patch) });
      confirmations.push(`Updated scenario ${s.scenarioId}`);
      continue;
    }

    if (op === 'DELETE' && s.scenarioId) {
      await auth(`/premium/career-profile/${s.scenarioId}`, { method: 'DELETE' });
      confirmations.push(`Deleted scenario ${s.scenarioId}`);
      continue;
    }

    if (op === 'CLONE' && s.sourceId) {
      await auth('/premium/career-profile/clone', { method: 'POST', body: JSON.stringify({
        sourceId  : s.sourceId,
        overrides : s.overrides || {}
      })});
      confirmations.push(`Cloned scenario ${s.sourceId}`);
      continue;
    }
  }

  /* ────────────────────────────────────────────────────
     5. COLLEGE PROFILE (single op per block)
     ──────────────────────────────────────────────────── */
  if (opsObj.collegeProfile?.op?.toUpperCase() === 'UPSERT' && opsObj.collegeProfile.data) {
    await auth('/premium/college-profile', { method: 'POST', body: JSON.stringify(opsObj.collegeProfile.data) });
    confirmations.push('Saved college profile');
  }

  return confirmations;
}