(define-module (tracks nodedb)
  #:export (nodedb
	    load-nodedb))

(use-modules (ice-9 binary-ports) (ice-9 textual-ports)
	     (rnrs bytevectors)
	     (srfi srfi-2) (srfi srfi-69)
	     (tracks register))

(define nodedb (make-hash-table))

(define (load-nodedb filename)
  (letrec* ((names (make-vector 65536 #f))
	    (nodes (make-hash-table))
	    (read-bv
	     (lambda (port n)
	       (and-let* ((v (get-bytevector-n port n))
			  ((not (eof-object? v)))
			  ((= (bytevector-length v) n)))
		 v)))
	    (bo (endianness big))
	    (read-u16
	     (lambda (port)
	       (and-let* ((v (read-bv port 2)))
		 (bytevector-u16-ref v 0 bo))))
	    (balance (lambda (n) (- n 32768)))
	    (read-int
	     (lambda (port)
	       (and-let* ((n (read-u16 port)))
		 (balance n))))
	    (read-node-entry
	     (lambda (port)
	       (and-let* ((v (read-bv port 8))
			  (b (lambda (v i)
			       (balance (bytevector-u16-ref v i bo))))
			  (x (b v 0)) (y (b v 2)) (z (b v 4)) (id (b v 6))
			  (c (list x y z))
			  (n (+ (ash id -2) 32768))
			  (p (bit-extract id 0 2)))
		 (and-let* ((s (vector-ref names n)))
		   (hash-table-set! nodes c (vector-ref s p)))
		 #t)))
	    (read-node-definition
	     (lambda (port)
	       (let* ((k (read-u16 port)) (v (get-line port)))
		 (when (and v (hash-table-exists? registered-tracks v))
		   (vector-set! names k
				(hash-table-ref registered-tracks v))))))
	    (read-node-definitions
	     (lambda (port)
	       (do ((i (read-int port) (- i 1))) ((zero? i))
		 (read-node-definition port))))
	    (read-nodes (lambda (port) (while (read-node-entry port))))
	    (read-ndb
	     (lambda (port)
	       (unless (equal? (get-u8 port) 1)
		 (error "wrong nodedb version"))
	       (read-node-definitions port)
	       (read-nodes port)
	       (set! nodedb nodes))))
    (call-with-input-file filename read-ndb #:binary #t)
    (format #t "Node database: ~d tracks in database~%"
	    (hash-table-size nodedb))))