// SPDX-License-Identifier: Apache-2.0

package firrtlTests.analyses

import firrtl.annotations.TargetToken.OfModule
import firrtl.analyses.InstanceGraph
import firrtl.graph.DiGraph
import firrtl.WDefInstance
import firrtl.passes._
import firrtl.testutils._

class InstanceGraphTests extends FirrtlFlatSpec {
  private def getEdgeSet(graph: DiGraph[String]): collection.Map[String, collection.Set[String]] = {
    (graph.getVertices.map { v => (v, graph.getEdges(v)) }).toMap
  }

  behavior.of("InstanceGraph")

  it should "recognize a simple hierarchy" in {
    val input = """
circuit Top :
  module Top :
    inst c1 of Child1
    inst c2 of Child2
  module Child1 :
    inst a of Child1a
    inst b of Child1b
    skip
  module Child1a :
    skip
  module Child1b :
    skip
  module Child2 :
    skip
"""
    val circuit = ToWorkingIR.run(parse(input))
    val graph = new InstanceGraph(circuit).graph.transformNodes(_.module)
    getEdgeSet(graph) shouldBe Map(
      "Top" -> Set("Child1", "Child2"),
      "Child1" -> Set("Child1a", "Child1b"),
      "Child2" -> Set(),
      "Child1a" -> Set(),
      "Child1b" -> Set()
    )
  }

  it should "find hierarchical instances correctly in disconnected hierarchies" in {
    val input = """
circuit Top :
  module Top :
    inst c of Child1
  module Child1 :
    skip

  module Top2 :
    inst a of Child2
    inst b of Child3
    skip
  module Child2 :
    inst a of Child2a
    inst b of Child2b
    skip
  module Child2a :
    skip
  module Child2b :
    skip
  module Child3 :
    skip
"""

    val circuit = ToWorkingIR.run(parse(input))
    val iGraph = new InstanceGraph(circuit)
    iGraph.findInstancesInHierarchy("Top") shouldBe Seq(Seq(WDefInstance("Top", "Top")))
    iGraph.findInstancesInHierarchy("Child1") shouldBe Seq(Seq(WDefInstance("Top", "Top"), WDefInstance("c", "Child1")))
    iGraph.findInstancesInHierarchy("Top2") shouldBe Nil
    iGraph.findInstancesInHierarchy("Child2") shouldBe Nil
    iGraph.findInstancesInHierarchy("Child2a") shouldBe Nil
    iGraph.findInstancesInHierarchy("Child2b") shouldBe Nil
    iGraph.findInstancesInHierarchy("Child3") shouldBe Nil
  }

  it should "recognize disconnected hierarchies" in {
    val input = """
circuit Top :
  module Top :
    inst c of Child1
  module Child1 :
    skip

  module Top2 :
    inst a of Child2
    inst b of Child3
    skip
  module Child2 :
    inst a of Child2a
    inst b of Child2b
    skip
  module Child2a :
    skip
  module Child2b :
    skip
  module Child3 :
    skip

"""
    val circuit = ToWorkingIR.run(parse(input))
    val graph = new InstanceGraph(circuit).graph.transformNodes(_.module)
    getEdgeSet(graph) shouldBe Map(
      "Top" -> Set("Child1"),
      "Top2" -> Set("Child2", "Child3"),
      "Child2" -> Set("Child2a", "Child2b"),
      "Child1" -> Set(),
      "Child2a" -> Set(),
      "Child2b" -> Set(),
      "Child3" -> Set()
    )
  }

  it should "not drop duplicate nodes when they collide as a result of transformNodes" in {
    val input =
      """circuit Top :
  module Buzz :
    skip
  module Fizz :
    inst b of Buzz
  module Foo :
    inst f1 of Fizz
  module Bar :
    inst f2 of Fizz
  module Top :
    inst f of Foo
    inst b of Bar
"""
    val circuit = ToWorkingIR.run(parse(input))
    val graph = (new InstanceGraph(circuit)).graph

    // Create graphs with edges from child to parent module
    // g1 has collisions on parents to children, ie. it combines:
    //   (f1, Fizz) -> (b, Buzz) and (f2, Fizz) -> (b, Buzz)
    val g1 = graph.transformNodes(_.module).reverse
    g1.getEdges("Fizz") shouldBe Set("Foo", "Bar")

    val g2 = graph.reverse.transformNodes(_.module)
    // g2 combines
    //   (f1, Fizz) -> (f, Foo) and (f2, Fizz) -> (b, Bar)
    g2.getEdges("Fizz") shouldBe Set("Foo", "Bar")
  }

  // Note that due to optimized implementations of Map1-4, at least 5 entries are needed to
  // experience non-determinism
  it should "preserve Module declaration order" in {
    val input = """
                  |circuit Top :
                  |  module Top :
                  |    inst c1 of Child1
                  |    inst c2 of Child2
                  |  module Child1 :
                  |    inst a of Child1a
                  |    inst b of Child1b
                  |    skip
                  |  module Child1a :
                  |    skip
                  |  module Child1b :
                  |    skip
                  |  module Child2 :
                  |    skip
                  |""".stripMargin
    val circuit = ToWorkingIR.run(parse(input))
    val instGraph = new InstanceGraph(circuit)
    val childMap = instGraph.getChildrenInstances
    childMap.keys.toSeq should equal(Seq("Top", "Child1", "Child1a", "Child1b", "Child2"))
  }

  // Note that due to optimized implementations of Map1-4, at least 5 entries are needed to
  // experience non-determinism
  it should "preserve Instance declaration order" in {
    val input = """
                  |circuit Top :
                  |  module Top :
                  |    inst a of Child
                  |    inst b of Child
                  |    inst c of Child
                  |    inst d of Child
                  |    inst e of Child
                  |    inst f of Child
                  |  module Child :
                  |    skip
                  |""".stripMargin
    val circuit = ToWorkingIR.run(parse(input))
    val instGraph = new InstanceGraph(circuit)
    val childMap = instGraph.getChildrenInstances
    val insts = childMap("Top").toSeq.map(_.name)
    insts should equal(Seq("a", "b", "c", "d", "e", "f"))
  }

  // Note that due to optimized implementations of Map1-4, at least 5 entries are needed to
  // experience non-determinism
  it should "have defined fullHierarchy order" in {
    val input = """
                  |circuit Top :
                  |  module Top :
                  |    inst a of Child
                  |    inst b of Child
                  |    inst c of Child
                  |    inst d of Child
                  |    inst e of Child
                  |  module Child :
                  |    skip
                  |""".stripMargin
    val circuit = ToWorkingIR.run(parse(input))
    val instGraph = new InstanceGraph(circuit)
    val hier = instGraph.fullHierarchy
    hier.keys.toSeq.map(_.name) should equal(Seq("Top", "a", "b", "c", "d", "e"))
  }

  behavior.of("InstanceGraph.staticInstanceCount")

  it should "report that there is one instance of the top module" in {
    val input =
      """|circuit Foo:
         |  module Foo:
         |    skip
         |""".stripMargin
    val iGraph = new InstanceGraph(ToWorkingIR.run(parse(input)))
    val expectedCounts = Map(OfModule("Foo") -> 1)
    iGraph.staticInstanceCount should be(expectedCounts)
  }

  it should "report correct number of instances for a sample circuit" in {
    val input =
      """|circuit Foo:
         |  module Baz:
         |    skip
         |  module Bar:
         |    inst baz1 of Baz
         |    inst baz2 of Baz
         |    inst baz3 of Baz
         |    skip
         |  module Foo:
         |    inst bar1 of Bar
         |    inst bar2 of Bar
         |""".stripMargin
    val iGraph = new InstanceGraph(ToWorkingIR.run(parse(input)))
    val expectedCounts = Map(OfModule("Foo") -> 1, OfModule("Bar") -> 2, OfModule("Baz") -> 3)
    iGraph.staticInstanceCount should be(expectedCounts)
  }

  it should "report zero instances for dead modules" in {
    val input =
      """|circuit Foo:
         |  module Bar:
         |    skip
         |  module Foo:
         |    skip
         |""".stripMargin
    val iGraph = new InstanceGraph(ToWorkingIR.run(parse(input)))
    val expectedCounts = Map(OfModule("Foo") -> 1, OfModule("Bar") -> 0)
    iGraph.staticInstanceCount should be(expectedCounts)
  }

  behavior.of("Reachable/Unreachable helper methods")

  they should "report correct reachable/unreachable counts" in {
    val input =
      """|circuit Top:
         |  module Unreachable:
         |    skip
         |  module Reachable:
         |    skip
         |  module Top:
         |    inst reachable of Reachable
         |""".stripMargin
    val iGraph = new InstanceGraph(ToWorkingIR.run(parse(input)))
    iGraph.modules should contain theSameElementsAs Seq(OfModule("Top"), OfModule("Reachable"), OfModule("Unreachable"))
    iGraph.reachableModules should contain theSameElementsAs Seq(OfModule("Top"), OfModule("Reachable"))
    iGraph.unreachableModules should contain theSameElementsAs Seq(OfModule("Unreachable"))
  }
}
