include "primitives.alh"
include "modelling.alh"
include "object_operations.alh"
include "conformance_scd.alh"
include "io.alh"
include "metamodels.alh"

Boolean function main(model : Element):
	String cmd
	Boolean running
	Element schedule_init
	Element schedule_run
	Element schedule
	String conforming

	schedule_init = create_schedule(model)
	schedule_run = read_root()

	while (bool_not(has_input())):
		if (read_attribute(model, "time", "start_time") == read_attribute(model, "time", "current_time")):
			schedule = schedule_init
		else:
			if (element_eq(schedule_run, read_root())):
				schedule_run = create_schedule(model)
			schedule = schedule_run
		//schedule = create_schedule(model)
		step_simulation(model, schedule)

	log("Finishing simulation, as we got input!")
	return True!

Element function create_schedule(model : Element):
	// Create nice graph first
	Element nodes
	Element successors
	String element_name
	Element incoming_links
	Element all_blocks

	nodes = allInstances(model, "Block")
	successors = create_node()
	while (read_nr_out(nodes) > 0):
		element_name = set_pop(nodes)
		if (bool_not(dict_in(successors, element_name))):
			dict_add(successors, element_name, create_node())

		if (is_nominal_instance(model, element_name, "ICBlock")):
			if (element_eq(read_attribute(model, element_name, "last_in"), read_root())):
				incoming_links = allIncomingAssociationInstances(model, element_name, "InitialCondition")
			else:
				incoming_links = create_node()
			if (is_nominal_instance(model, element_name, "DerivatorBlock")):
				Element new_incoming_links
				new_incoming_links = allIncomingAssociationInstances(model, element_name, "Link")
				while (read_nr_out(new_incoming_links) > 0):
					list_append(incoming_links, set_pop(new_incoming_links))
		else:
			incoming_links = allIncomingAssociationInstances(model, element_name, "Link")

		while (read_nr_out(incoming_links) > 0):
			String source
			source = readAssociationSource(model, set_pop(incoming_links))
			if (bool_not(dict_in(successors, source))):
				dict_add(successors, source, create_node())
			set_add(successors[source], element_name)
	
	Element values
	values = create_node()
	dict_add(values, "S", create_node())
	dict_add(values, "index", 0)
	dict_add(values, "indices", create_node())
	dict_add(values, "lowlink", create_node())
	dict_add(values, "onStack", create_node())
	dict_add(values, "successors", successors)
	dict_add(values, "SCC", create_node())

	nodes = allInstances(model, "Block")
	while (read_nr_out(nodes) > 0):
		strongconnect(set_pop(nodes), values)

	return values["SCC"]!

Integer function min(a : Integer, b : Integer):
	if (a < b):
		return a!
	else:
		return b!

Void function strongconnect(v : String, values : Element):
	if (dict_in(values["indices"], v)):
		return!

	dict_overwrite(values["indices"], v, values["index"])
	dict_overwrite(values["lowlink"], v, values["index"])
	dict_overwrite(values, "index", cast_integer(values["index"]) + 1)

	list_append(values["S"], v)
	dict_overwrite(values["onStack"], v, True)
	
	Element successors
	String w
	successors = values["successors"][v]
	while (read_nr_out(successors) > 0):
		w = set_pop(successors)
		if (bool_not(dict_in(values["indices"], w))):
			strongconnect(w, values)
			dict_overwrite(values["lowlink"], v, min(values["lowlink"][v], values["lowlink"][w]))
		elif (dict_in(values["onStack"], w)):
			if (values["onStack"][w]):
				dict_overwrite(values["lowlink"], v, min(values["lowlink"][v], values["indices"][w]))
	
	if (value_eq(values["lowlink"][v], values["indices"][v])):
		Element scc
		scc = create_node()
		// It will always differ now
		w = list_pop_final(values["S"])
		list_append(scc, w)
		dict_overwrite(values["onStack"], w, False)
		while (w != v):
			w = list_pop_final(values["S"])
			list_append(scc, w)
			dict_overwrite(values["onStack"], w, False)
		list_insert(values["SCC"], scc, 0)

	return!

String function readType(model : Element, name : String):
	return reverseKeyLookup(model["metamodel"]["model"], dict_read_node(model["type_mapping"], model["model"][name]))!

Boolean function solve_scc(model : Element, scc : Element):
	Element m
	Integer i
	Integer j
	String block
	String blocktype
	Element incoming
	String selected
	Float constant
	Element t

	// Construct the matrix first, with as many rows as there are variables
	// Number of columns is 1 higher
	i = 0
	m = create_node()
	while (i < read_nr_out(scc)):
		j = 0
		t = create_node()
		while (j < (read_nr_out(scc) + 1)):
			list_append(t, 0.0)
			j = j + 1
		list_append(m, t)
		i = i + 1

	log("Matrix ready!")
	// Matrix initialized to 0.0
	i = 0
	while (i < read_nr_out(scc)):
		log("Creating matrix row")
		// First element of scc
		block = scc[i]
		blocktype = readType(model, block)

		// First write 1 in the current block
		dict_overwrite(m[i], i, 1.0)

		// Now check all blocks that are incoming
		if (blocktype == "AdditionBlock"):
			constant = 0.0
		elif (blocktype == "MultiplyBlock"):
			constant = 1.0

		log("Generating matrix for " + blocktype)
		log("Block: " + block)
		incoming = allIncomingAssociationInstances(model, block, "Link")

		Integer index_to_write_constant
		index_to_write_constant = -1
		log("Iterating over incoming")
		while (read_nr_out(incoming) > 0):
			log("Iteration")
			selected = readAssociationSource(model, set_pop(incoming))

			if (set_in(scc, selected)):
				// Part of the loop, so in the index of selected in scc
				// Five options:
				if (blocktype == "AdditionBlock"):
					// 1) AdditionBlock
					// Add the negative of this signal, which is as of yet unknown
					// x = y + z --> x - y - z = 0
					dict_overwrite(m[i], list_index_of(scc, selected), -1.0)
				elif (blocktype == "MultiplyBlock"):
					// 2) MultiplyBlock
					if (index_to_write_constant != -1):
						return False!
					index_to_write_constant = list_index_of(scc, selected)
				elif (blocktype == "NegatorBlock"):
					// 3) NegatorBlock
					// Add the positive of the signal, which is as of yet unknown
					dict_overwrite(m[i], list_index_of(scc, selected), 1.0)
				elif (blocktype == "DelayBlock"):
					// 5) DelayBlock
					// Just copies a single value
					dict_overwrite(m[i], list_index_of(scc, selected), -1.0)
				else:
					// Block that cannot be handled
					return False!
			else:
				// A constant, which we can assume is already computed and thus usable
				if (blocktype == "AdditionBlock"):
					constant = constant + cast_float(read_attribute(model, selected, "signal"))
					dict_overwrite(m[i], read_nr_out(scc), constant)
				elif (blocktype == "MultiplyBlock"):
					constant = constant * cast_float(read_attribute(model, selected, "signal"))
					// Not written to constant part, as multiplies a variable

				// Any other block is impossible:
				// * Constant would never be part of a SCC
				// * Delay would never get an incoming constant
				// * Negation and Inverse only get 1 input, which is a variable in a loop
				// * Integrator and Derivator never get an incoming constant

		if (index_to_write_constant != -1):
			dict_overwrite(m[i], index_to_write_constant, -constant)

		i = i + 1

	// Constructed a complete matrix, so we can start!
	log("Constructed matrix to solve:")
	log(matrix2string(m))

	// Solve matrix now
	eliminateGaussJordan(m)

	// Now go over m and set signals for each element
	// Assume that everything worked out...
	i = 0
	while (i < read_nr_out(m)):
		block = scc[i]
		unset_attribute(model, block, "signal")
		instantiate_attribute(model, block, "signal", m[i][read_nr_out(scc)])
		log((("Solved " + block) + " to ") + cast_string(m[i][read_nr_out(scc)]))
		i = i + 1

	return True!

Integer function list_index_of(lst : Element, elem : Element):
	Integer i
	i = 0
	while (i < read_nr_out(lst)):
		if (value_eq(list_read(lst, i), elem)):
			return i!
		else:
			i = i + 1
	return -1!

Void function step_simulation(model : Element, schedule : Element):
	String time
	Float signal
	Element incoming
	String selected
	String block
	String elem
	String blocktype
	Element memory_blocks
	Integer i
	Float delta_t
	Element scc

	time = "time"
	delta_t = 0.1

	memory_blocks = create_node()
	output("SIM_TIME " + cast_string(read_attribute(model, time, "current_time")))
	i = 0
	while (i < read_nr_out(schedule)):
		scc = list_read(schedule, i)
		i = i + 1

		if (list_len(scc) > 1):
			log("Solving algebraic loop!")
			if (bool_not(solve_scc(model, scc))):
				output("ALGEBRAIC_LOOP")
				return !
		else:
			block = set_pop(scc)

			// Execute "block"
			blocktype = readType(model, block)
			if (blocktype == "ConstantBlock"):
				signal = read_attribute(model, block, "value")
			elif (blocktype == "AdditionBlock"):
				signal = 0.0
				incoming = allIncomingAssociationInstances(model, block, "Link")
				while (read_nr_out(incoming) > 0):
					selected = readAssociationSource(model, set_pop(incoming))
					signal = signal + cast_float(read_attribute(model, selected, "signal"))
			elif (blocktype == "MultiplyBlock"):
				signal = 1.0
				incoming = allIncomingAssociationInstances(model, block, "Link")
				while (read_nr_out(incoming) > 0):
					selected = readAssociationSource(model, set_pop(incoming))
					signal = signal * cast_float(read_attribute(model, selected, "signal"))
			elif (blocktype == "NegatorBlock"):
				incoming = allIncomingAssociationInstances(model, block, "Link")
				signal = 0.0
				while (read_nr_out(incoming) > 0):
					selected = readAssociationSource(model, set_pop(incoming))
					signal = float_neg(cast_float(read_attribute(model, selected, "signal")))
			elif (blocktype == "InverseBlock"):
				signal = 0.0
				incoming = allIncomingAssociationInstances(model, block, "Link")
				while (read_nr_out(incoming) > 0):
					selected = readAssociationSource(model, set_pop(incoming))
					signal = float_division(1.0, cast_float(read_attribute(model, selected, "signal")))
			elif (blocktype == "DelayBlock"):
				signal = 0.0
				if (element_eq(read_attribute(model, block, "last_in"), read_root())):
					// No memory yet, so use initial condition
					incoming = allIncomingAssociationInstances(model, block, "InitialCondition")
					while (read_nr_out(incoming) > 0):
						selected = readAssociationSource(model, set_pop(incoming))
						signal = cast_float(read_attribute(model, selected, "signal"))
				else:
					signal = read_attribute(model, block, "last_in")
					unset_attribute(model, block, "last_in")
				set_add(memory_blocks, block)
			elif (blocktype == "IntegratorBlock"):
				if (element_eq(read_attribute(model, block, "last_in"), read_root())):
					// No history yet, so use initial values
					incoming = allIncomingAssociationInstances(model, block, "InitialCondition")
					while (read_nr_out(incoming) > 0):
						selected = readAssociationSource(model, set_pop(incoming))
						signal = cast_float(read_attribute(model, selected, "signal"))
				else:
					signal = cast_float(read_attribute(model, block, "last_in")) + (delta_t * cast_float(read_attribute(model, block, "last_out")))
					unset_attribute(model, block, "last_in")
					unset_attribute(model, block, "last_out")
				instantiate_attribute(model, block, "last_out", signal)
				set_add(memory_blocks, block)
			elif (blocktype == "DerivatorBlock"):
				if (element_eq(read_attribute(model, block, "last_in"), read_root())):
					// No history yet, so use initial values
					incoming = allIncomingAssociationInstances(model, block, "InitialCondition")
					while (read_nr_out(incoming) > 0):
						selected = readAssociationSource(model, set_pop(incoming))
						signal = cast_float(read_attribute(model, selected, "signal"))
				else:
					incoming = allIncomingAssociationInstances(model, block, "Link")
					while (read_nr_out(incoming) > 0):
						selected = readAssociationSource(model, set_pop(incoming))
						signal = (cast_float(read_attribute(model, selected, "signal")) - cast_float(read_attribute(model, block, "last_in"))) / delta_t
					unset_attribute(model, block, "last_in")
				set_add(memory_blocks, block)
			elif (blocktype == "ProbeBlock"):
				incoming = allIncomingAssociationInstances(model, block, "Link")
				while (read_nr_out(incoming) > 0):
					selected = readAssociationSource(model, set_pop(incoming))
					signal = cast_float(read_attribute(model, selected, "signal"))
					output((("SIM_PROBE " + cast_string(read_attribute(model, block, "name"))) + " ") + cast_string(signal))

			unset_attribute(model, block, "signal")
			instantiate_attribute(model, block, "signal", signal)
	output("SIM_END")
	
	while (read_nr_out(memory_blocks) > 0):
		block = set_pop(memory_blocks)
		// Update memory
		incoming = allIncomingAssociationInstances(model, block, "Link")
		while (read_nr_out(incoming) > 0):
			selected = readAssociationSource(model, set_pop(incoming))
			instantiate_attribute(model, block, "last_in", cast_float(read_attribute(model, selected, "signal")))

	// Increase simulation time
	Float new_time
	new_time = cast_float(read_attribute(model, time, "current_time")) + delta_t
	unset_attribute(model, time, "current_time")
	instantiate_attribute(model, time, "current_time", new_time)

	return !

Void function eliminateGaussJordan(m : Element):
	Integer i
	Integer j
	Integer f
	Integer g
	Boolean searching
	Element t
	Float divisor

	i = 0
	j = 0

	while (i < read_nr_out(m)):
		// Make sure pivot m[i][j] != 0, swapping if necessary
		while (cast_float(m[i][j]) == 0.0):
			// Is zero, so find row which is not zero
			f = i + 1
			searching = True
			while (searching):
				if (f >= read_nr_out(m)):
					// No longer any rows left, so just increase column counter
					searching = False
					j = j + 1
				else:
					if (cast_float(m[f][j]) == 0.0):
						// Also zero, so continue
						f = f + 1
					else:
						// Found non-zero, so swap row
						t = cast_float(m[f])
						dict_overwrite(m, f, cast_float(m[i]))
						dict_overwrite(m, i, t)
						searching = False
			// If we have increased j, we will just start the loop again (possibly), as m[i][j] might be zero again

		// Pivot in m[i][j] guaranteed to not be 0
		// Now divide complete row by value of m[i][j] to make it equal 1
		f = j
		divisor = cast_float(m[i][j])
		while (f < read_nr_out(m[i])):
			dict_overwrite(m[i], f, float_division(cast_float(m[i][f]), divisor))
			f = f + 1

		// Eliminate all rows in the j-th column, except the i-th row
		f = 0
		while (f < read_nr_out(m)):
			if (bool_not(f == i)):
				g = j
				divisor = cast_float(m[f][j])
				while (g < read_nr_out(m[f])):
					dict_overwrite(m[f], g, cast_float(m[f][g]) - (divisor * cast_float(m[i][g])))
					g = g + 1
			f = f + 1

		// Increase row and column
		i = i + 1
		j = j + 1

	return !

String function matrix2string(m : Element):
	Integer i
	Integer j
	String result

	result = ""
	i = 0
	while (i < read_nr_out(m)):
		j = 0
		while (j < read_nr_out(m[i])):
			result = result + cast_string(m[i][j]) + ", "
			j = j + 1
		i = i + 1
		result = result + "\n"
	return result!