package intervalv2

import (
	"testing"
	"time"

	"github.com/grafana/grafana-plugin-sdk-go/backend"
	"github.com/stretchr/testify/assert"

	"github.com/grafana/grafana/pkg/services/datasources"
)

func TestIntervalCalculator_Calculate(t *testing.T) {
	calculator := NewCalculator(CalculatorOptions{})

	timeNow := time.Now()

	testCases := []struct {
		name       string
		timeRange  backend.TimeRange
		resolution int64
		expected   string
	}{
		{"from 5m to now and default resolution", backend.TimeRange{From: timeNow, To: timeNow.Add(5 * time.Minute)}, 0, "200ms"},
		{"from 5m to now and 500 resolution", backend.TimeRange{From: timeNow, To: timeNow.Add(5 * time.Minute)}, 500, "500ms"},
		{"from 15m to now and default resolution", backend.TimeRange{From: timeNow, To: timeNow.Add(15 * time.Minute)}, 0, "500ms"},
		{"from 15m to now and 100 resolution", backend.TimeRange{From: timeNow, To: timeNow.Add(15 * time.Minute)}, 100, "10s"},
		{"from 30m to now and default resolution", backend.TimeRange{From: timeNow, To: timeNow.Add(30 * time.Minute)}, 0, "1s"},
		{"from 30m to now and 3000 resolution", backend.TimeRange{From: timeNow, To: timeNow.Add(30 * time.Minute)}, 3000, "500ms"},
		{"from 1h to now and default resolution", backend.TimeRange{From: timeNow, To: timeNow.Add(time.Hour)}, 0, "2s"},
		{"from 1h to now and 1000 resoluion", backend.TimeRange{From: timeNow, To: timeNow.Add(time.Hour)}, 1000, "5s"},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			interval := calculator.Calculate(tc.timeRange, time.Millisecond*1, tc.resolution)
			assert.Equal(t, tc.expected, interval.Text)
		})
	}
}

func TestIntervalCalculator_CalculateSafeInterval(t *testing.T) {
	calculator := NewCalculator(CalculatorOptions{})

	timeNow := time.Now()

	testCases := []struct {
		name           string
		timeRange      backend.TimeRange
		safeResolution int64
		expected       string
	}{
		{"from 5m to now", backend.TimeRange{From: timeNow, To: timeNow.Add(5 * time.Minute)}, 11000, "20ms"},
		{"from 15m to now", backend.TimeRange{From: timeNow, To: timeNow.Add(15 * time.Minute)}, 11000, "100ms"},
		{"from 30m to now", backend.TimeRange{From: timeNow, To: timeNow.Add(30 * time.Minute)}, 11000, "200ms"},
		{"from 24h to now", backend.TimeRange{From: timeNow, To: timeNow.Add(1440 * time.Minute)}, 11000, "10s"},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			interval := calculator.CalculateSafeInterval(tc.timeRange, tc.safeResolution)
			assert.Equal(t, tc.expected, interval.Text)
		})
	}
}

func TestRoundInterval(t *testing.T) {
	testCases := []struct {
		name     string
		interval time.Duration
		expected time.Duration
	}{
		{"10ms", time.Millisecond * 10, time.Millisecond * 1},
		{"15ms", time.Millisecond * 15, time.Millisecond * 10},
		{"30ms", time.Millisecond * 30, time.Millisecond * 20},
		{"45ms", time.Millisecond * 45, time.Millisecond * 50},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			assert.Equal(t, tc.expected, roundInterval(tc.interval))
		})
	}
}

func TestFormatDuration(t *testing.T) {
	testCases := []struct {
		name     string
		duration time.Duration
		expected string
	}{
		{"61s", time.Second * 61, "1m"},
		{"30ms", time.Millisecond * 30, "30ms"},
		{"23h", time.Hour * 23, "23h"},
		{"24h", time.Hour * 24, "1d"},
		{"367d", time.Hour * 24 * 367, "1y"},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			assert.Equal(t, tc.expected, FormatDuration(tc.duration))
		})
	}
}

func TestGetIntervalFrom(t *testing.T) {
	testCases := []struct {
		name            string
		dsInfo          *datasources.DataSource
		queryInterval   string
		queryIntervalMs int64
		defaultInterval time.Duration
		expected        time.Duration
	}{
		{"45s", nil, "45s", 0, time.Second * 15, time.Second * 45},
		{"45", nil, "45", 0, time.Second * 15, time.Second * 45},
		{"2m", nil, "2m", 0, time.Second * 15, time.Minute * 2},
		{"1d", nil, "1d", 0, time.Second * 15, time.Hour * 24},
		{"intervalMs", nil, "", 45000, time.Second * 15, time.Second * 45},
		{"intervalMs sub-seconds", nil, "", 45200, time.Second * 15, time.Millisecond * 45200},
		{"defaultInterval when interval empty", nil, "", 0, time.Second * 15, time.Second * 15},
		{"defaultInterval when intervalMs 0", nil, "", 0, time.Second * 15, time.Second * 15},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			actual, err := GetIntervalFrom(tc.queryInterval, "", tc.queryIntervalMs, tc.defaultInterval)
			assert.Nil(t, err)
			assert.Equal(t, tc.expected, actual)
		})
	}
}