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from pywy.core import Executor, ChannelDescriptor
from pywy.core import PywyPlan
from pywy.platforms.jvm.channels import DISPATCHABLE_CHANNEL_DESCRIPTOR
from pywy.platforms.jvm.graph import NodeDispatch, WGraphDispatch
from pywy.platforms.jvm.operator import JVMExecutionOperator

class JVMExecutor(Executor):

    def __init__(self):
        super(JVMExecutor, self).__init__()

    def execute(self, plan):
        pywyPlan: PywyPlan = plan
        graph = WGraphDispatch(pywyPlan.sinks)

        # TODO get this information by a configuration and ideally by the context
        descriptor_default: ChannelDescriptor = DISPATCHABLE_CHANNEL_DESCRIPTOR

        def execute(op_current: NodeDispatch, op_next: NodeDispatch):
            if op_current is None:
                return

            jvm_current: JVMExecutionOperator = op_current.current
            if jvm_current.outputs == 0:
                jvm_current.execute(jvm_current.inputChannel, [])
                return

            if op_next is None:
                return

            jvm_next: JVMExecutionOperator = op_next.current
            outputs = jvm_current.get_output_channeldescriptors()
            inputs = jvm_next.get_input_channeldescriptors()

            intersect = outputs.intersection(inputs)
            if len(intersect) == 0:
                raise Exception(
                    "The operator(A) {} can't connect with (B) {}, "
                    "because the output of (A) is {} and the input of (B) is {} ".format(
                        jvm_current,
                        jvm_next,
                        outputs,
                        inputs
                    )
                )

            if len(intersect) > 1:
                if descriptor_default is None:
                    raise Exception(
                        "The interaction between the operator (A) {} and (B) {}, "
                        "can't be decided because are several channel availables {}".format(
                            jvm_current,
                            jvm_next,
                            intersect
                        )
                    )
                descriptor = descriptor_default
            else:
                descriptor = intersect.pop()

            # TODO validate if is valite for several output
            jvm_current.outputChannel[0] = descriptor.create_instance()

            jvm_current.execute(jvm_current.inputChannel, jvm_current.outputChannel)

            jvm_next.inputChannel = jvm_current.outputChannel

        graph.traversal(graph.starting_nodes, execute)


        starting: WayangJVMOperator = graph.starting_nodes[0].current.dispatch_operator
        while starting.previous[0]:
            print(starting)
            #print(starting.nexts[0])
            starting = starting.previous[0]
            if len(starting.previous) == 0 :
                break
        print(starting)