(local 
	{: r
	: move
	: branch
	: branch-link}
	(require :host.assembler.opcodes))
(local {: any : slice : push : map} (require :deps.lume))
(local {: word->byte} (require :host.util))
(local {: emulate} (require :host.util.emulator))

(fn label [name] {:label name})
(fn label? [value]
	(if (and (= (type value) :table) (. value :label)) true false))

(fn insert-label [table label index]
	(if (. table :label)
			(:error (.. "Duplicate label " label))
			(tset table :labels label index)))

(fn assemble [forms offset]
	(let [state {:labels {} :instructions [] :reverse-labels []}]
		(each [_ form (ipairs forms)]
			(if (= (type form) :string)
					(insert-label state form (+ offset (* 4 (length (. state :instructions)))))
					(push (. state :instructions)
								(if (any (slice form 2) label?)
										(do
											(push (. state :reverse-labels) (+ 1 (length (. state :instructions))))
											form)
										((. form 1) (table.unpack (slice form 2)))))))
		state))

; (fn link [{: labels : instructions : reverse-labels}]
; 	())

(assemble
	[[move (r 8) (r 2)]
	 :label-1
	 [move (r 9) (r 3)]
	 [branch (label :label-1)]]
	0x8000)

(let [assembly (assemble [[move (r 8) 127]])
      byte-string (table.concat (map (. assembly :instructions) word->byte) "")]
  (emulate byte-string))