package gleak

import (
	"os"
	"os/signal"
	"sync"
	"time"

	. "github.com/onsi/ginkgo/v2"
	. "github.com/onsi/gomega"
)

// Note: Go's stack dumps (backtraces) always contain forward slashes, even on
// Windows. The following tests thus work the same both on *nix and Windows.

var _ = Describe("HaveLeaked", func() {

	It("renders indented goroutine information including (malformed) backtrace", func() {
		gs := []Goroutine{
			{
				ID:    42,
				State: "stoned",
				Backtrace: `main.foo.func1()
		/home/foo/test.go:6 +0x28
created by main.foo
		/home/foo/test.go:5 +0x64
`,
			},
		}
		m := HaveLeaked().(*HaveLeakedMatcher)
		Expect(m.listGoroutines(gs, 1)).To(Equal(`    goroutine 42 [stoned]
        main.foo.func1() at foo/test.go:6
        created by main.foo at foo/test.go:5`))

		gs = []Goroutine{
			{
				ID:    42,
				State: "stoned",
				Backtrace: `main.foo.func1()
		/home/foo/test.go:6 +0x28
created by main.foo
		/home/foo/test.go:5 +0x64`,
			},
		}
		Expect(m.listGoroutines(gs, 1)).To(Equal(`    goroutine 42 [stoned]
        main.foo.func1() at foo/test.go:6
        created by main.foo at foo/test.go:5`))

		gs = []Goroutine{
			{
				ID:    42,
				State: "stoned",
				Backtrace: `main.foo.func1()
		/home/foo/test.go:6 +0x28
created by main.foo
		/home/foo/test.go:5`,
			},
		}
		Expect(m.listGoroutines(gs, 1)).To(Equal(`    goroutine 42 [stoned]
        main.foo.func1() at foo/test.go:6
        created by main.foo at foo/test.go:5`))

		gs = []Goroutine{
			{
				ID:    42,
				State: "stoned",
				Backtrace: `main.foo.func1()
		/home/foo/test.go:6 +0x28
created by main.foo`,
			},
		}
		Expect(m.listGoroutines(gs, 1)).To(Equal(`    goroutine 42 [stoned]
        main.foo.func1() at foo/test.go:6
        created by main.foo`))
	})

	It("considers testing and runtime goroutines not to be leaks", func() {
		Eventually(Goroutines).WithTimeout(2*time.Second).WithPolling(250*time.Millisecond).
			ShouldNot(HaveLeaked(), "should not find any leaks by default")
	})

	When("using signals", func() {

		It("doesn't find leaks", func() {
			c := make(chan os.Signal, 1)
			signal.Notify(c, os.Interrupt)
			Eventually(Goroutines).WithTimeout(2*time.Second).WithPolling(250*time.Millisecond).
				ShouldNot(HaveLeaked(), "found signal.Notify leaks")

			signal.Reset(os.Interrupt)
			Eventually(Goroutines).WithTimeout(2*time.Second).WithPolling(250*time.Millisecond).
				ShouldNot(HaveLeaked(), "found signal.Reset leaks")
		})

	})

	It("checks against list of expected goroutines", func() {
		By("taking a snapshot")
		gs := Goroutines()
		m := HaveLeaked(gs)

		By("starting a goroutine")
		done := make(chan struct{})
		var once sync.Once
		go func() {
			<-done
		}()
		defer once.Do(func() { close(done) })

		By("detecting the goroutine")
		Expect(m.Match(Goroutines())).To(BeTrue())

		By("terminating the goroutine and ensuring it has terminated")
		once.Do(func() { close(done) })
		Eventually(func() (bool, error) {
			return m.Match(Goroutines())
		}).Should(BeFalse())
	})

	Context("failure messages", func() {

		var snapshot []Goroutine

		BeforeEach(func() {
			snapshot = Goroutines()
			done := make(chan struct{})
			go func() {
				<-done
			}()
			DeferCleanup(func() {
				close(done)
				Eventually(Goroutines).ShouldNot(HaveLeaked(snapshot))
			})
		})

		It("returns a failure message", func() {
			m := HaveLeaked(snapshot)
			gs := Goroutines()
			Expect(m.Match(gs)).To(BeTrue())
			Expect(m.FailureMessage(gs)).To(MatchRegexp(`Expected to leak 1 goroutines:
    goroutine \d+ \[.+\]
        .* at .*:\d+
        created by .* at .*:\d+`))
		})

		It("returns a negated failure message", func() {
			m := HaveLeaked(snapshot)
			gs := Goroutines()
			Expect(m.Match(gs)).To(BeTrue())
			Expect(m.NegatedFailureMessage(gs)).To(MatchRegexp(`Expected not to leak 1 goroutines:
    goroutine \d+ \[.+\]
        .* at .*:\d+
        created by .* at .*:\d+`))
		})

		When("things go wrong", func() {

			It("rejects unsupported filter args types", func() {
				Expect(func() { _ = HaveLeaked(42) }).To(PanicWith(
					"HaveLeaked expected a string, []Goroutine, or GomegaMatcher, but got:\n    <int>: 42"))
			})

			It("accepts plain strings as filters", func() {
				m := HaveLeaked("foo.bar")
				Expect(m.Match([]Goroutine{
					{TopFunction: "foo.bar"},
				})).To(BeFalse())
			})

			It("expects actual to be a slice of Goroutine", func() {
				m := HaveLeaked()
				Expect(m.Match(nil)).Error().To(MatchError(
					"HaveLeaked matcher expects an array or slice of goroutines.  Got:\n    <nil>: nil"))
				Expect(m.Match("foo!")).Error().To(MatchError(
					"HaveLeaked matcher expects an array or slice of goroutines.  Got:\n    <string>: foo!"))
				Expect(m.Match([]string{"foo!"})).Error().To(MatchError(
					"HaveLeaked matcher expects an array or slice of goroutines.  Got:\n    <[]string | len:1, cap:1>: [\"foo!\"]"))
			})

			It("handles filter matcher errors", func() {
				m := HaveLeaked(HaveField("foobar", BeNil()))
				Expect(m.Match([]Goroutine{
					{ID: 0},
				})).Error().To(HaveOccurred())
			})

		})

	})

	Context("wrapped around test nodes", func() {

		var snapshot []Goroutine

		When("not leaking", func() {

			BeforeEach(func() {
				snapshot = Goroutines()
			})

			AfterEach(func() {
				Eventually(Goroutines).ShouldNot(HaveLeaked(snapshot))
			})

			It("doesn't leak in test", func() {
				// nothing
			})

		})

		When("leaking", func() {

			done := make(chan struct{})

			BeforeEach(func() {
				snapshot = Goroutines()
			})

			AfterEach(func() {
				Expect(Goroutines()).To(HaveLeaked(snapshot))
				close(done)
				Eventually(Goroutines).ShouldNot(HaveLeaked(snapshot))
			})

			It("leaks in test", func() {
				go func() {
					<-done
				}()
			})

		})

	})

	Context("handling file names and paths in backtraces", func() {

		When("ReportFilenameWithPath is true", Ordered, func() {

			var oldState bool

			BeforeAll(func() {
				oldState = ReportFilenameWithPath
				ReportFilenameWithPath = true
				DeferCleanup(func() {
					ReportFilenameWithPath = oldState
				})
			})

			It("doesn't shorten filenames", func() {
				Expect(formatFilename("/home/foo/bar/baz.go")).To(Equal("/home/foo/bar/baz.go"))
			})

		})

		When("ReportFilenameWithPath is false", Ordered, func() {

			var oldState bool

			BeforeAll(func() {
				oldState = ReportFilenameWithPath
				ReportFilenameWithPath = false
				DeferCleanup(func() {
					ReportFilenameWithPath = oldState
				})
			})

			It("does return only package and filename, but no path", func() {
				Expect(formatFilename("/home/foo/bar/baz.go")).To(Equal("bar/baz.go"))
				Expect(formatFilename("/bar/baz.go")).To(Equal("bar/baz.go"))
				Expect(formatFilename("/baz.go")).To(Equal("baz.go"))
				Expect(formatFilename("/")).To(Equal("/"))
			})

		})

	})

})