package restic

import (
	"bytes"
	"encoding/json"
	"fmt"
	"github.com/rs/zerolog/log"
	"github.com/stretchr/testify/assert"
	"os"
	"os/exec"
	"testing"
	"time"
)

func TestWrapper_LastSnapshot(t *testing.T) {
	shot1 := ResticSnapshot{
		Id:   "shot1",
		Time: time.Date(2020, 10, 10, 10, 10, 10, 10, time.UTC),
	}
	shot2 := ResticSnapshot{
		Id:   "shot2",
		Time: time.Date(2022, 11, 11, 11, 11, 11, 11, time.UTC),
	}

	cases := []struct {
		label     string
		snapshots []ResticSnapshot
		expected  ResticSnapshot
	}{
		{
			"None yet",
			[]ResticSnapshot{},
			ResticSnapshot{
				Id:   "(no snapshots yet)",
				Time: time.Time{},
			},
		},
		{
			"take the last from the array",
			[]ResticSnapshot{shot1, shot2},
			shot2,
		},
	}

	for _, tc := range cases {
		t.Run(tc.label, func(t *testing.T) {
			wrapper := Wrapper{
				LatestSnapshots: tc.snapshots,
			}
			last := wrapper.LastSnapshot()

			assert.Equal(t, tc.expected.Id, last.Id)
			assert.Equal(t, tc.expected.Time.Hour(), last.Time.Hour())
			assert.Equal(t, tc.expected.Time.Minute(), last.Time.Minute())
		})
	}
}

// a very clever way to test exec.Command in go: https://jamiethompson.me/posts/Unit-Testing-Exec-Command-In-Golang/
func fakeExecCommand(whichTest string) func(args ...string) *exec.Cmd {
	return func(args ...string) *exec.Cmd {
		cs := []string{"-test.run=" + whichTest, "--", "restic"}
		cs = append(cs, args...)
		cmd := exec.Command(os.Args[0], cs...)
		cmd.Env = []string{"GO_TEST_PROCESS=1"}
		return cmd
	}
}

func TestCmdnapshotSuccessWithinTime(t *testing.T) {
	if os.Getenv("GO_TEST_PROCESS") != "1" {
		return
	}
	snapshots := []ResticSnapshot{
		{
			Id:   "id1",
			Time: timeNow(),
			Tree: "tree",
			Paths: []string{
				"/path/one",
				"/path/two",
			},
		},
		{
			Id:   "id2",
			Time: timeNow(),
			Tree: "tree2",
			Paths: []string{
				"/path2/one",
				"/path2/two",
			},
		},
	}
	bytes, _ := json.Marshal(snapshots)
	fmt.Fprintf(os.Stdout, string(bytes))
	os.Exit(0)
}

func TestCmdSuccessWithinTime(t *testing.T) {
	if os.Getenv("GO_TEST_PROCESS") != "1" {
		return
	}
	fmt.Fprintf(os.Stdout, "some output\n")
	os.Exit(0)
}
func TestCmdExitCode1WithinTime(t *testing.T) {
	if os.Getenv("GO_TEST_PROCESS") != "1" {
		return
	}
	fmt.Fprintf(os.Stdout, "some output\n")
	os.Exit(1)
}
func TestCmdExitCode3WithinTime(t *testing.T) {
	if os.Getenv("GO_TEST_PROCESS") != "1" {
		return
	}
	fmt.Fprintf(os.Stdout, "some output\n")
	os.Exit(3)
}

func TestCmdTakesLongerThan2sButOutputsFaster(t *testing.T) {
	if os.Getenv("GO_TEST_PROCESS") != "1" {
		return
	}
	// don't forget \n as the scanner splits on ScanLines
	time.Sleep(1 * time.Second)
	fmt.Fprintf(os.Stdout, "some output after 1s\n")
	time.Sleep(2 * time.Second)
	fmt.Fprintf(os.Stdout, "some output after 3s\n")
	os.Exit(0)
}

func TestCmdTakesLongerThan2sToOutputAnything(t *testing.T) {
	if os.Getenv("GO_TEST_PROCESS") != "1" {
		return
	}
	time.Sleep(3 * time.Second)
	fmt.Fprintf(os.Stdout, "some output, too late!\n")
	os.Exit(0)
}

func TestBackup_ExitCode1_ReturnsError(t *testing.T) {
	resticCmd = fakeExecCommand("TestCmdExitCode1WithinTime")

	wrapper := Wrapper{}
	err := wrapper.Backup(&Config{})

	assert.Error(t, err)
}

func TestBackup_ExitCode3_IssuesWarning(t *testing.T) {
	resticCmd = fakeExecCommand("TestCmdExitCode3WithinTime")
	var logBuffer bytes.Buffer
	log.Logger = log.Output(&logBuffer)

	wrapper := Wrapper{}
	err := wrapper.Backup(&Config{})

	assert.NoError(t, err)
	assert.Contains(t, logBuffer.String(), "permission problem?")
}

func TestBackup_OutputsAndFinishesAsExpected(t *testing.T) {
	resticCmd = fakeExecCommand("TestCmdSuccessWithinTime")
	var logBuffer bytes.Buffer
	log.Logger = log.Output(&logBuffer)

	wrapper := Wrapper{}
	err := wrapper.Backup(&Config{})

	assert.NoError(t, err)
	assert.Contains(t, logBuffer.String(), "some output")
}

func TestBackup_OutputsBefore2sButStillTakesLonger(t *testing.T) {
	resticCmd = fakeExecCommand("TestCmdTakesLongerThan2sButOutputsFaster")
	cmdTimeout = 2 * time.Second

	wrapper := Wrapper{}
	err := wrapper.Backup(&Config{})

	assert.NoError(t, err)
}

func TestBackup_TakesLongerThanNeededToOutput_TimesOut(t *testing.T) {
	resticCmd = fakeExecCommand("TestCmdTakesLongerThan2sToOutputAnything")
	cmdTimeout = 2 * time.Second

	wrapper := Wrapper{}
	err := wrapper.Backup(&Config{})

	assert.ErrorIs(t, err, ResticCmdTimeoutError)
}

func TestUpdateLatestSnapshot_TakesLongerThanNeededToOutput_TimesOut(t *testing.T) {
	resticCmd = fakeExecCommand("TestCmdTakesLongerThan2sToOutputAnything")
	cmdTimeout = 2 * time.Second

	wrapper := Wrapper{}
	err := wrapper.UpdateLatestSnapshots(&Config{})

	assert.Empty(t, wrapper.LatestSnapshots)
	assert.ErrorIs(t, err, ResticCmdTimeoutError)
}

func TestUpdateLatestSnapshots_FromJSONOutputOfRestic(t *testing.T) {
	resticCmd = fakeExecCommand("TestCmdnapshotSuccessWithinTime")

	wrapper := Wrapper{}
	err := wrapper.UpdateLatestSnapshots(&Config{})

	assert.NoError(t, err)
	assert.Equal(t, "id1", wrapper.LatestSnapshots[0].Id)
	assert.Equal(t, "/path/two", wrapper.LatestSnapshots[0].Paths[1])
	assert.Equal(t, "id2", wrapper.LatestSnapshots[1].Id)
	assert.Equal(t, "/path2/two", wrapper.LatestSnapshots[1].Paths[1])
}