From 63eeb29fbff86e9e47005e1ca44d472a75479a7a Mon Sep 17 00:00:00 2001
From: otivm <sandor@factoryfouroh.info>
Date: Mon, 27 Apr 2026 10:36:38 +0000
Subject: [PATCH] Add SQLite connection and /api/map/:h5/:epoch endpoint

---
 server/index.js | 82 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)

diff --git a/server/index.js b/server/index.js
index 4efaba1..bc32455 100644
--- a/server/index.js
+++ b/server/index.js
@@ -4,15 +4,40 @@ import { readFile, writeFile, mkdir } from 'fs/promises'
 import { join, dirname } from 'path'
 import { fileURLToPath } from 'url'
 import { existsSync } from 'fs'
+import Database from 'better-sqlite3'
 
 const __dirname = dirname(fileURLToPath(import.meta.url))
 const ROOT = join(__dirname, '..')
 const DIST = join(ROOT, 'dist')
 const SAVES_DIR = join(ROOT, 'data', 'saves')
+const DB_PATH = join(ROOT, 'data', 'otivm.sqlite3')
 
 // Ensure saves directory exists
 await mkdir(SAVES_DIR, { recursive: true })
 
+// Open TESSERA database — read-only
+const db = new Database(DB_PATH, { readonly: true })
+
+// Prepared statements
+const stmtEpoch = db.prepare(
+  'SELECT sl_offset_cm FROM paleo_epochs WHERE epoch_key = ?'
+)
+
+const stmtH7 = db.prepare(`
+  SELECT
+    h7,
+    SUM(CASE WHEN elev_cm > ? THEN 1 ELSE 0 END) AS h7_land,
+    COUNT(*) AS h9_total
+  FROM tessera_cells
+  WHERE h5 = ? AND status = 2
+  GROUP BY h7
+`)
+
+// Convert hex string H3 ID to BigInt integer for DB lookup
+function h3HexToInt(hexStr) {
+  return BigInt('0x' + hexStr)
+}
+
 const fastify = Fastify({ logger: false })
 
 // Serve built frontend
@@ -21,6 +46,63 @@ await fastify.register(fastifyStatic, {
   prefix: '/',
 })
 
+// --- TESSERA map endpoint ---
+// Returns H7-aggregated land/sea classification for one H5 waypoint at one epoch.
+// h5param: H3 res-5 cell ID as hex string (e.g. '851e805bfffffff')
+// epochKey: named epoch from paleo_epochs (e.g. 'roman_14bce')
+// Response: { epoch_key, sl_offset_cm, h5, cells: [{ h7, h7_land, h9_total, is_land }] }
+fastify.get('/api/map/:h5/:epoch', async (req, reply) => {
+  const { h5: h5param, epoch: epochKey } = req.params
+
+  // Validate H5 — must be 15-char lowercase hex
+  if (!/^[0-9a-f]{15}$/.test(h5param)) {
+    return reply.code(400).send({ error: 'Invalid H5 ID' })
+  }
+
+  // Validate epoch key — alphanumeric and underscores only
+  if (!/^[a-z0-9_]+$/.test(epochKey)) {
+    return reply.code(400).send({ error: 'Invalid epoch key' })
+  }
+
+  // Resolve epoch to sea level offset
+  const epoch = stmtEpoch.get(epochKey)
+  if (!epoch) {
+    return reply.code(404).send({ error: `Unknown epoch: ${epochKey}` })
+  }
+
+  const slOffsetCm = epoch.sl_offset_cm
+
+  // Convert H5 hex string to integer for DB query
+  let h5int
+  try {
+    h5int = h3HexToInt(h5param)
+  } catch {
+    return reply.code(400).send({ error: 'Malformed H5 ID' })
+  }
+
+  // Query H7 land/sea classification
+  const rows = stmtH7.all(slOffsetCm, h5int)
+
+  if (!rows.length) {
+    return reply.code(404).send({ error: `No data for H5: ${h5param}` })
+  }
+
+  // Apply majority rule: H7 cell is land if >50% of H9 children are land
+  const cells = rows.map(row => ({
+    h7: row.h7.toString(16),          // return as hex string
+    h7_land: row.h7_land,
+    h9_total: row.h9_total,
+    is_land: row.h7_land * 2 > row.h9_total ? 1 : 0,
+  }))
+
+  return reply.send({
+    epoch_key: epochKey,
+    sl_offset_cm: slOffsetCm,
+    h5: h5param,
+    cells,
+  })
+})
+
 // Load save state
 fastify.get('/api/save/:token', async (req, reply) => {
   const { token } = req.params