import { db } from '../db.js';

const ISO = /^\d{4}-\d{2}-\d{2}$/;

function ensureDay(day) {
  db.prepare('INSERT OR IGNORE INTO training_days (day) VALUES (?)').run(day);
}

// Write an entry's metric values and bump any personal-best records they beat.
// Pushes beaten records onto `newRecords`. Used by both create and update.
function writeValues(entryId, values, newRecords) {
  if (!Array.isArray(values)) return;
  const ins = db.prepare('INSERT INTO entry_values (entry_id, metric_id, value) VALUES (?, ?, ?)');
  for (const v of values) {
    if (!v || v.metric_id == null) continue;
    const metricId = Number(v.metric_id);
    const value = Number(v.value) || 0;
    ins.run(entryId, metricId, value);

    const m = db.prepare(
      'SELECT id, name, record, higher_is_better, unit FROM category_metrics WHERE id = ? AND track_record = 1'
    ).get(metricId);
    if (m) {
      const beats = m.record == null
        || (m.higher_is_better ? value > m.record : value < m.record);
      if (beats) {
        db.prepare('UPDATE category_metrics SET record = ? WHERE id = ?').run(value, metricId);
        newRecords.push({ metric_id: m.id, name: m.name, unit: m.unit, value, previous: m.record });
      }
    }
  }
}

function dayPayload(day) {
  const td = db.prepare('SELECT day, notes FROM training_days WHERE day = ?').get(day)
    || { day, notes: '' };
  const entries = db.prepare(
    'SELECT id, category_id, note, created_at FROM entries WHERE day = ? ORDER BY id'
  ).all(day);
  const valuesByEntry = new Map();
  if (entries.length) {
    const ids = entries.map((e) => e.id);
    const rows = db.prepare(
      `SELECT entry_id, metric_id, value FROM entry_values WHERE entry_id IN (${ids.map(() => '?').join(',')})`
    ).all(...ids);
    for (const r of rows) {
      if (!valuesByEntry.has(r.entry_id)) valuesByEntry.set(r.entry_id, []);
      valuesByEntry.get(r.entry_id).push({ metric_id: r.metric_id, value: r.value });
    }
  }
  const plans = db.prepare(
    'SELECT category_id, note FROM plans WHERE day = ?'
  ).all(day);
  return {
    day: td.day,
    notes: td.notes,
    entries: entries.map((e) => ({ ...e, values: valuesByEntry.get(e.id) || [] })),
    plans,
  };
}

export default async function entryRoutes(app) {
  app.get('/api/day/:day', async (req, reply) => {
    const { day } = req.params;
    if (!ISO.test(day)) return reply.code(400).send({ error: 'Bad date' });
    return dayPayload(day);
  });

  app.post('/api/entries', async (req, reply) => {
    const { day, category_id, values, note } = req.body || {};
    if (!ISO.test(day || '')) return reply.code(400).send({ error: 'Bad date' });
    const cat = db.prepare('SELECT id FROM categories WHERE id = ?').get(Number(category_id));
    if (!cat) return reply.code(400).send({ error: 'Unknown category' });

    const newRecords = [];
    const tx = db.transaction(() => {
      ensureDay(day);
      const { lastInsertRowid: entryId } = db.prepare(
        'INSERT INTO entries (day, category_id, note) VALUES (?, ?, ?)'
      ).run(day, cat.id, String(note || ''));
      writeValues(entryId, values, newRecords);
    });
    tx();
    return { ...dayPayload(day), newRecords };
  });

  // Edit an existing entry: replace its values and note (and bump records).
  app.put('/api/entries/:id', async (req, reply) => {
    const id = Number(req.params.id);
    const entry = db.prepare('SELECT id, day FROM entries WHERE id = ?').get(id);
    if (!entry) return reply.code(404).send({ error: 'Not found' });
    const { values, note } = req.body || {};

    const newRecords = [];
    const tx = db.transaction(() => {
      if (note !== undefined) {
        db.prepare('UPDATE entries SET note = ? WHERE id = ?').run(String(note || ''), id);
      }
      db.prepare('DELETE FROM entry_values WHERE entry_id = ?').run(id);
      writeValues(id, values, newRecords);
    });
    tx();
    return { ...dayPayload(entry.day), newRecords };
  });

  app.delete('/api/entries/:id', async (req, reply) => {
    const id = Number(req.params.id);
    const row = db.prepare('SELECT day FROM entries WHERE id = ?').get(id);
    db.prepare('DELETE FROM entries WHERE id = ?').run(id);
    return reply.send(row ? dayPayload(row.day) : { ok: true });
  });

  app.put('/api/day/:day/notes', async (req, reply) => {
    const { day } = req.params;
    if (!ISO.test(day)) return reply.code(400).send({ error: 'Bad date' });
    const notes = String((req.body && req.body.notes) || '');
    ensureDay(day);
    db.prepare('UPDATE training_days SET notes = ? WHERE day = ?').run(notes, day);
    return { ok: true, notes };
  });
}