package cron_test

import (
	"testing"
	"time"

	"github.com/stretchr/testify/require"

	"github.com/coder/coder/v2/coderd/schedule/cron"
)

func Test_Weekly(t *testing.T) {
	t.Parallel()
	testCases := []struct {
		name               string
		spec               string
		at                 time.Time
		expectedNext       time.Time
		expectedMin        time.Duration
		expectedDaysOfWeek string
		expectedError      string
		expectedCron       string
		expectedLocation   *time.Location
		expectedString     string
		expectedTime       string
	}{
		{
			name:               "with timezone",
			spec:               "CRON_TZ=US/Central 30 9 * * 1-5",
			at:                 time.Date(2022, 4, 1, 14, 29, 0, 0, time.UTC),
			expectedNext:       time.Date(2022, 4, 1, 14, 30, 0, 0, time.UTC),
			expectedMin:        24 * time.Hour,
			expectedDaysOfWeek: "Mon-Fri",
			expectedError:      "",
			expectedCron:       "30 9 * * 1-5",
			expectedLocation:   mustLocation(t, "US/Central"),
			expectedString:     "CRON_TZ=US/Central 30 9 * * 1-5",
			expectedTime:       "9:30AM",
		},
		{
			name:               "without timezone",
			spec:               "30 9 * * 1-5",
			at:                 time.Date(2022, 4, 1, 9, 29, 0, 0, time.UTC),
			expectedNext:       time.Date(2022, 4, 1, 9, 30, 0, 0, time.UTC),
			expectedMin:        24 * time.Hour,
			expectedDaysOfWeek: "Mon-Fri",
			expectedError:      "",
			expectedCron:       "30 9 * * 1-5",
			expectedLocation:   time.UTC,
			expectedString:     "CRON_TZ=UTC 30 9 * * 1-5",
			expectedTime:       "9:30AM",
		},
		{
			name:               "24h format",
			spec:               "30 13 * * 1-5",
			at:                 time.Date(2022, 4, 1, 13, 29, 0, 0, time.UTC),
			expectedNext:       time.Date(2022, 4, 1, 13, 30, 0, 0, time.UTC),
			expectedMin:        24 * time.Hour,
			expectedDaysOfWeek: "Mon-Fri",
			expectedError:      "",
			expectedCron:       "30 13 * * 1-5",
			expectedLocation:   time.UTC,
			expectedString:     "CRON_TZ=UTC 30 13 * * 1-5",
			expectedTime:       "1:30PM",
		},
		{
			name:               "convoluted with timezone",
			spec:               "CRON_TZ=US/Central */5 12-18 * * 1,3,6",
			at:                 time.Date(2022, 4, 1, 14, 29, 0, 0, time.UTC),
			expectedNext:       time.Date(2022, 4, 2, 17, 0, 0, 0, time.UTC), // Apr 1 was a Friday in 2022
			expectedMin:        5 * time.Minute,
			expectedDaysOfWeek: "Mon,Wed,Sat",
			expectedError:      "",
			expectedCron:       "*/5 12-18 * * 1,3,6",
			expectedLocation:   mustLocation(t, "US/Central"),
			expectedString:     "CRON_TZ=US/Central */5 12-18 * * 1,3,6",
			expectedTime:       "cron(*/5 12-18)",
		},
		{
			name:               "another convoluted example",
			spec:               "CRON_TZ=US/Central 10,20,40-50 * * * *",
			at:                 time.Date(2022, 4, 1, 14, 29, 0, 0, time.UTC),
			expectedNext:       time.Date(2022, 4, 1, 14, 40, 0, 0, time.UTC),
			expectedMin:        time.Minute,
			expectedDaysOfWeek: "daily",
			expectedError:      "",
			expectedCron:       "10,20,40-50 * * * *",
			expectedLocation:   mustLocation(t, "US/Central"),
			expectedString:     "CRON_TZ=US/Central 10,20,40-50 * * * *",
			expectedTime:       "cron(10,20,40-50 *)",
		},
		{
			name:          "time.Local will bite you",
			spec:          "CRON_TZ=Local 30 9 * * 1-5",
			at:            time.Time{},
			expectedNext:  time.Time{},
			expectedError: "schedules scoped to time.Local are not supported",
		},
		{
			name:          "invalid schedule",
			spec:          "asdfasdfasdfsd",
			at:            time.Time{},
			expectedNext:  time.Time{},
			expectedError: "validate weekly schedule: expected schedule to consist of 5 fields with an optional CRON_TZ=<timezone> prefix",
		},
		{
			name:          "invalid location",
			spec:          "CRON_TZ=Fictional/Country 30 9 * * 1-5",
			at:            time.Time{},
			expectedNext:  time.Time{},
			expectedError: "parse schedule: provided bad location Fictional/Country: unknown time zone Fictional/Country",
		},
		{
			name:          "invalid schedule with 3 fields",
			spec:          "CRON_TZ=Fictional/Country 30 9 1-5",
			at:            time.Time{},
			expectedNext:  time.Time{},
			expectedError: "validate weekly schedule: expected schedule to consist of 5 fields with an optional CRON_TZ=<timezone> prefix",
		},
		{
			name:          "invalid schedule with 3 fields and no timezone",
			spec:          "30 9 1-5",
			at:            time.Time{},
			expectedNext:  time.Time{},
			expectedError: "validate weekly schedule: expected schedule to consist of 5 fields with an optional CRON_TZ=<timezone> prefix",
		},
		{
			name:          "valid schedule with 5 fields but month and dom not set to *",
			spec:          "30 9 1 1 1-5",
			at:            time.Time{},
			expectedNext:  time.Time{},
			expectedError: "validate weekly schedule: expected day-of-month and month to be *",
		},
		{
			name:          "valid schedule with 5 fields and timezone but month and dom not set to *",
			spec:          "CRON_TZ=Europe/Dublin 30 9 1 1 1-5",
			at:            time.Time{},
			expectedNext:  time.Time{},
			expectedError: "validate weekly schedule: expected day-of-month and month to be *",
		},
	}

	for _, testCase := range testCases {
		t.Run(testCase.name, func(t *testing.T) {
			t.Parallel()
			actual, err := cron.Weekly(testCase.spec)
			if testCase.expectedError == "" {
				nextTime := actual.Next(testCase.at)
				require.NoError(t, err)
				require.Equal(t, testCase.expectedNext, nextTime)
				require.Equal(t, testCase.expectedCron, actual.Cron())
				require.Equal(t, testCase.expectedLocation, actual.Location())
				require.Equal(t, testCase.expectedString, actual.String())
				require.Equal(t, testCase.expectedMin, actual.Min())
				require.Equal(t, testCase.expectedDaysOfWeek, actual.DaysOfWeek())
				require.Equal(t, testCase.expectedTime, actual.Time())
			} else {
				require.EqualError(t, err, testCase.expectedError)
				require.Nil(t, actual)
			}
		})
	}
}

func TestIsWithinRange(t *testing.T) {
	t.Parallel()
	testCases := []struct {
		name                string
		spec                string
		at                  time.Time
		expectedWithinRange bool
		expectedError       string
	}{
		// "* 9-18 * * 1-5" should be interpreted as a continuous time range from 09:00:00 to 18:59:59, Monday through Friday
		{
			name:                "Right before the start of the time range",
			spec:                "* 9-18 * * 1-5",
			at:                  mustParseTime(t, time.RFC1123, "Mon, 02 Jun 2025 8:59:59 UTC"),
			expectedWithinRange: false,
		},
		{
			name:                "Start of the time range",
			spec:                "* 9-18 * * 1-5",
			at:                  mustParseTime(t, time.RFC1123, "Mon, 02 Jun 2025 9:00:00 UTC"),
			expectedWithinRange: true,
		},
		{
			name:                "9:01 AM - One minute after the start of the time range",
			spec:                "* 9-18 * * 1-5",
			at:                  mustParseTime(t, time.RFC1123, "Mon, 02 Jun 2025 9:01:00 UTC"),
			expectedWithinRange: true,
		},
		{
			name:                "2PM - The middle of the time range",
			spec:                "* 9-18 * * 1-5",
			at:                  mustParseTime(t, time.RFC1123, "Mon, 02 Jun 2025 14:00:00 UTC"),
			expectedWithinRange: true,
		},
		{
			name:                "6PM - One hour before the end of the time range",
			spec:                "* 9-18 * * 1-5",
			at:                  mustParseTime(t, time.RFC1123, "Mon, 02 Jun 2025 18:00:00 UTC"),
			expectedWithinRange: true,
		},
		{
			name:                "End of the time range",
			spec:                "* 9-18 * * 1-5",
			at:                  mustParseTime(t, time.RFC1123, "Mon, 02 Jun 2025 18:59:59 UTC"),
			expectedWithinRange: true,
		},
		{
			name:                "Right after the end of the time range",
			spec:                "* 9-18 * * 1-5",
			at:                  mustParseTime(t, time.RFC1123, "Mon, 02 Jun 2025 19:00:00 UTC"),
			expectedWithinRange: false,
		},
		{
			name:                "7:01PM - One minute after the end of the time range",
			spec:                "* 9-18 * * 1-5",
			at:                  mustParseTime(t, time.RFC1123, "Mon, 02 Jun 2025 19:01:00 UTC"),
			expectedWithinRange: false,
		},
		{
			name:                "2AM - Significantly outside the time range",
			spec:                "* 9-18 * * 1-5",
			at:                  mustParseTime(t, time.RFC1123, "Mon, 02 Jun 2025 02:00:00 UTC"),
			expectedWithinRange: false,
		},
		{
			name:                "Outside the day range #1",
			spec:                "* 9-18 * * 1-5",
			at:                  mustParseTime(t, time.RFC1123, "Sat, 07 Jun 2025 14:00:00 UTC"),
			expectedWithinRange: false,
		},
		{
			name:                "Outside the day range #2",
			spec:                "* 9-18 * * 1-5",
			at:                  mustParseTime(t, time.RFC1123, "Sun, 08 Jun 2025 14:00:00 UTC"),
			expectedWithinRange: false,
		},
		{
			name:                "Check that Sunday is supported with value 0",
			spec:                "* 9-18 * * 0",
			at:                  mustParseTime(t, time.RFC1123, "Sun, 08 Jun 2025 14:00:00 UTC"),
			expectedWithinRange: true,
		},
		{
			name:          "Check that value 7 is rejected as out of range",
			spec:          "* 9-18 * * 7",
			at:            mustParseTime(t, time.RFC1123, "Sun, 08 Jun 2025 14:00:00 UTC"),
			expectedError: "end of range (7) above maximum (6): 7",
		},
	}

	for _, testCase := range testCases {
		testCase := testCase
		t.Run(testCase.name, func(t *testing.T) {
			t.Parallel()
			sched, err := cron.Weekly(testCase.spec)
			if testCase.expectedError != "" {
				require.Error(t, err)
				require.Contains(t, err.Error(), testCase.expectedError)
				return
			}
			require.NoError(t, err)
			withinRange := sched.IsWithinRange(testCase.at)
			require.Equal(t, testCase.expectedWithinRange, withinRange)
		})
	}
}

func mustParseTime(t *testing.T, layout, value string) time.Time {
	t.Helper()
	parsedTime, err := time.Parse(layout, value)
	require.NoError(t, err)
	return parsedTime
}

func mustLocation(t *testing.T, s string) *time.Location {
	t.Helper()
	loc, err := time.LoadLocation(s)
	require.NoError(t, err)
	return loc
}