// SPDX-License-Identifier: Apache-2.0

package chiselTests

import chisel3._
import chisel3.stage.ChiselStage
import chisel3.testers.BasicTester

trait BundleSpecUtils {
  class BundleFooBar extends Bundle {
    val foo = UInt(16.W)
    val bar = UInt(16.W)
    override def cloneType: this.type = (new BundleFooBar).asInstanceOf[this.type]
  }
  class BundleBarFoo extends Bundle {
    val bar = UInt(16.W)
    val foo = UInt(16.W)
    override def cloneType: this.type = (new BundleBarFoo).asInstanceOf[this.type]
  }
  class BundleFoo extends Bundle {
    val foo = UInt(16.W)
    override def cloneType: this.type = (new BundleFoo).asInstanceOf[this.type]
  }
  class BundleBar extends Bundle {
    val bar = UInt(16.W)
    override def cloneType: this.type = (new BundleBar).asInstanceOf[this.type]
  }

  class BadSeqBundle extends Bundle {
    val bar = Seq(UInt(16.W), UInt(8.W), UInt(4.W))
    override def cloneType: this.type = (new BadSeqBundle).asInstanceOf[this.type]
  }

  class MyModule(output: Bundle, input: Bundle) extends Module {
    val io = IO(new Bundle {
      val in = Input(input)
      val out = Output(output)
    })
    io.out <> io.in
  }

  class BundleSerializationTest extends BasicTester {
    // Note that foo is higher order because its defined earlier in the Bundle
    val bundle = Wire(new BundleFooBar)
    bundle.foo := 0x1234.U
    bundle.bar := 0x5678.U
    // To UInt
    val uint = bundle.asUInt
    assert(uint.getWidth == 32) // elaboration time
    assert(uint === "h12345678".asUInt(32.W))
    // Back to Bundle
    val bundle2 = uint.asTypeOf(new BundleFooBar)
    assert(0x1234.U === bundle2.foo)
    assert(0x5678.U === bundle2.bar)
    stop()
  }
}

class BundleSpec extends ChiselFlatSpec with BundleSpecUtils with Utils {
  "Bundles with the same fields but in different orders" should "bulk connect" in {
    ChiselStage.elaborate { new MyModule(new BundleFooBar, new BundleBarFoo) }
  }

  "Bundles" should "follow UInt serialization/deserialization API" in {
    assertTesterPasses { new BundleSerializationTest }
  }

  "Bulk connect on Bundles" should "check that the fields match" in {
    (the [ChiselException] thrownBy extractCause[ChiselException] {
      ChiselStage.elaborate { new MyModule(new BundleFooBar, new BundleFoo) }
    }).getMessage should include ("Right Record missing field")

    (the [ChiselException] thrownBy extractCause[ChiselException] {
      ChiselStage.elaborate { new MyModule(new BundleFoo, new BundleFooBar) }
    }).getMessage should include ("Left Record missing field")
  }

  "Bundles" should "not be able to use Seq for constructing hardware" in {
    (the[ChiselException] thrownBy extractCause[ChiselException] {
      ChiselStage.elaborate {
        new Module {
          val io = IO(new Bundle {
            val b = new BadSeqBundle
          })
        }
      }
    }).getMessage should include("Public Seq members cannot be used to define Bundle elements")
  }

  "Bundles" should "be allowed to have Seq if need be" in {
    assertTesterPasses {
      new BasicTester {
        val m = Module(new Module {
          val io = IO(new Bundle {
            val b = new BadSeqBundle with IgnoreSeqInBundle
          })
        })
        stop()
      }
    }
  }

  "Bundles" should "be allowed to have non-Chisel Seqs" in {
    assertTesterPasses {
      new BasicTester {
        val m = Module(new Module {
          val io = IO(new Bundle {
            val f = Output(UInt(8.W))
            val unrelated = (0 to 10).toSeq
            val unrelated2 = Seq("Hello", "World", "Chisel")
          })
          io.f := 0.U
        })
        stop()
      }
    }
  }

  "Bundles" should "not have aliased fields" in {
    (the[ChiselException] thrownBy extractCause[ChiselException] {
      ChiselStage.elaborate { new Module {
        val io = IO(Output(new Bundle {
          val a = UInt(8.W)
          val b = a
        }))
        io.a := 0.U
        io.b := 1.U
      } }
    }).getMessage should include("aliased fields")
  }

  "Unbound bundles sharing a field" should "not error" in {
    ChiselStage.elaborate {
      new RawModule {
        val foo = new Bundle {
          val x = UInt(8.W)
        }
        val bar = new Bundle {
          val y = foo.x
        }
      }
    }
  }

  "Bound Data" should "have priority in setting ref over unbound Data" in {
    class MyModule extends RawModule {
      val foo = IO(new Bundle {
        val x = Output(UInt(8.W))
      })
      foo.x := 0.U // getRef on foo.x is None.get without fix
      val bar = new Bundle {
        val y = foo.x
      }
    }
    ChiselStage.emitChirrtl(new MyModule)
  }
}