/**
 * Wake-up context builder for NoteLett palace.
 *
 * Builds L0/L1/L2 layered context within a configurable token budget.
 * Uses @bytelyst/palace shared wakeup builder for assembly + truncation.
 */

import { buildWakeUpLayers, WAKEUP_PRESETS, estimateTokens, truncateToTokenBudget } from '@bytelyst/palace';
import type { WakeUpContext } from '@bytelyst/palace';
import { config } from '../../lib/config.js';
import { embedText, stripHtmlForEmbedding } from '../../lib/embeddings.js';
import { getWing, listRooms, listMemories, searchSemantic, getWingSummary } from './repository.js';
import type { PalaceMemoryDoc, PalaceWingDoc } from './types.js';

export type { WakeUpContext };

export interface NoteLettWakeUpContext extends WakeUpContext {
  wingId: string;
  wingName: string;
}

const NOTELETT_PRESET = WAKEUP_PRESETS.notelett ?? {
  totalBudget: 600, l0Budget: 50, l1Budget: 150, l2Budget: 400,
};

/**
 * Build wake-up context for a workspace/wing.
 *
 * L0 — Identity: workspace name + room topics (~50 tokens)
 * L1 — Critical Facts: recent decisions/preferences/insights (~150 tokens)
 * L2 — Task Context: semantically relevant memories (~400 tokens)
 */
export async function buildNoteLettWakeUp(
  userId: string,
  productId: string,
  wingId: string,
  taskDescription?: string,
): Promise<NoteLettWakeUpContext> {
  const wing = await getWing(userId, productId, wingId);
  if (!wing) {
    return {
      text: '',
      layers: [],
      totalChars: 0,
      truncated: false,
      wingId,
      wingName: 'Unknown',
    };
  }

  const budget = {
    ...NOTELETT_PRESET,
    totalBudget: config.PALACE_WAKE_UP_BUDGET,
  };

  const l0 = await buildL0Identity(userId, productId, wing);
  const l1 = await buildL1CriticalFacts(userId, productId, wingId, wing);
  const l2 = await buildL2TaskContext(userId, productId, wingId, taskDescription);

  const ctx = buildWakeUpLayers(l0, l1, l2, budget);

  return {
    ...ctx,
    wingId,
    wingName: wing.name,
  };
}

/**
 * L0 — Identity: workspace name, description, room topics.
 */
async function buildL0Identity(
  userId: string,
  productId: string,
  wing: PalaceWingDoc,
): Promise<string> {
  const rooms = await listRooms(userId, productId, wing.id);
  const roomNames = rooms.map(r => r.name).slice(0, 10).join(', ');

  const parts = [`Workspace: ${wing.name}`];
  if (wing.description) parts.push(wing.description);
  if (roomNames) parts.push(`Topics: ${roomNames}`);

  return parts.join('\n');
}

/**
 * L1 — Critical Facts: recent decisions, preferences, insights.
 * Uses cached L1 if available, otherwise regenerates.
 */
async function buildL1CriticalFacts(
  userId: string,
  productId: string,
  wingId: string,
  wing: PalaceWingDoc,
): Promise<string> {
  // Try cached L1
  if (wing.l1Cache && wing.l1CacheUpdatedAt) {
    const cacheAge = Date.now() - new Date(wing.l1CacheUpdatedAt).getTime();
    if (cacheAge < 24 * 3600_000) return wing.l1Cache;
  }

  // Rebuild from recent decisions + preferences + insights
  const factHalls = ['decisions', 'preferences', 'insights'] as const;
  const recentFacts: PalaceMemoryDoc[] = [];

  for (const hall of factHalls) {
    const mems = await listMemories(userId, productId, {
      wingId,
      hall,
      limit: 5,
    });
    recentFacts.push(...mems);
  }

  if (recentFacts.length === 0) return '';

  // Sort by recency
  recentFacts.sort((a, b) => b.updatedAt.localeCompare(a.updatedAt));

  const lines = recentFacts.slice(0, 8).map(m => `- [${m.hall}] ${m.content}`);
  return lines.join('\n');
}

/**
 * L2 — Task Context: semantically relevant memories (or recent if no task).
 */
async function buildL2TaskContext(
  userId: string,
  productId: string,
  wingId: string,
  taskDescription?: string,
): Promise<string> {
  let memories: PalaceMemoryDoc[];

  if (taskDescription && taskDescription.trim().length > 0) {
    const embedding = await embedText(taskDescription);
    if (embedding) {
      memories = await searchSemantic(userId, productId, taskDescription, embedding, wingId, 8);
    } else {
      memories = await listMemories(userId, productId, { wingId, limit: 8 });
    }
  } else {
    memories = await listMemories(userId, productId, { wingId, limit: 8 });
  }

  if (memories.length === 0) return '';

  const lines = memories.map(m => `- [${m.hall}] ${m.content}`);
  return lines.join('\n');
}

/**
 * Regenerate L1 cache for a wing (called after memory extraction).
 */
export async function regenerateCriticalFacts(
  userId: string,
  productId: string,
  wingId: string,
): Promise<string> {
  const wing = await getWing(userId, productId, wingId);
  if (!wing) return '';

  const l1 = await buildL1CriticalFacts(userId, productId, wingId, wing);

  // Update wing doc with cached L1
  const { getCollection } = await import('../../lib/datastore.js');
  const col = getCollection<PalaceWingDoc>('palace_wings', '/userId');
  await col.update(wingId, userId, {
    l1Cache: l1,
    l1CacheUpdatedAt: new Date().toISOString(),
  } as Partial<PalaceWingDoc>);

  return l1;
}