package dmcache

import (
	"errors"
	"testing"

	"github.com/influxdata/telegraf/testutil"
	"github.com/stretchr/testify/require"
)

var (
	measurement              = "dmcache"
	badFormatOutput          = []string{"cs-1: 0 4883791872 cache 8 1018/1501122 512 7/464962 139 352643 "}
	good2DevicesFormatOutput = []string{
		"cs-1: 0 4883791872 cache 8 1018/1501122 512 7/464962 139 352643 15 46 0 7 0 1 writeback 2 migration_threshold 2048 mq 10 random_threshold 4 sequential_threshold 512 discard_promote_adjustment 1 read_promote_adjustment 4 write_promote_adjustment 8",
		"cs-2: 0 4294967296 cache 8 72352/1310720 128 26/24327168 2409 286 265 524682 0 0 0 1 writethrough 2 migration_threshold 2048 mq 10 random_threshold 4 sequential_threshold 512 discard_promote_adjustment 1 read_promote_adjustment 4 write_promote_adjustment 8",
	}
)

func TestPerDeviceGoodOutput(t *testing.T) {
	var acc testutil.Accumulator
	var plugin = &DMCache{
		PerDevice: true,
		getCurrentStatus: func() ([]string, error) {
			return good2DevicesFormatOutput, nil
		},
	}

	err := plugin.Gather(&acc)
	require.NoError(t, err)

	tags1 := map[string]string{
		"device": "cs-1",
	}
	fields1 := map[string]interface{}{
		"length":             4883791872,
		"metadata_blocksize": 8,
		"metadata_used":      1018,
		"metadata_total":     1501122,
		"cache_blocksize":    512,
		"cache_used":         7,
		"cache_total":        464962,
		"read_hits":          139,
		"read_misses":        352643,
		"write_hits":         15,
		"write_misses":       46,
		"demotions":          0,
		"promotions":         7,
		"dirty":              0,
	}
	acc.AssertContainsTaggedFields(t, measurement, fields1, tags1)

	tags2 := map[string]string{
		"device": "cs-2",
	}
	fields2 := map[string]interface{}{
		"length":             4294967296,
		"metadata_blocksize": 8,
		"metadata_used":      72352,
		"metadata_total":     1310720,
		"cache_blocksize":    128,
		"cache_used":         26,
		"cache_total":        24327168,
		"read_hits":          2409,
		"read_misses":        286,
		"write_hits":         265,
		"write_misses":       524682,
		"demotions":          0,
		"promotions":         0,
		"dirty":              0,
	}
	acc.AssertContainsTaggedFields(t, measurement, fields2, tags2)

	tags3 := map[string]string{
		"device": "all",
	}

	fields3 := map[string]interface{}{
		"length":             9178759168,
		"metadata_blocksize": 16,
		"metadata_used":      73370,
		"metadata_total":     2811842,
		"cache_blocksize":    640,
		"cache_used":         33,
		"cache_total":        24792130,
		"read_hits":          2548,
		"read_misses":        352929,
		"write_hits":         280,
		"write_misses":       524728,
		"demotions":          0,
		"promotions":         7,
		"dirty":              0,
	}
	acc.AssertContainsTaggedFields(t, measurement, fields3, tags3)
}

func TestNotPerDeviceGoodOutput(t *testing.T) {
	var acc testutil.Accumulator
	var plugin = &DMCache{
		PerDevice: false,
		getCurrentStatus: func() ([]string, error) {
			return good2DevicesFormatOutput, nil
		},
	}

	err := plugin.Gather(&acc)
	require.NoError(t, err)

	tags := map[string]string{
		"device": "all",
	}

	fields := map[string]interface{}{
		"length":             9178759168,
		"metadata_blocksize": 16,
		"metadata_used":      73370,
		"metadata_total":     2811842,
		"cache_blocksize":    640,
		"cache_used":         33,
		"cache_total":        24792130,
		"read_hits":          2548,
		"read_misses":        352929,
		"write_hits":         280,
		"write_misses":       524728,
		"demotions":          0,
		"promotions":         7,
		"dirty":              0,
	}
	acc.AssertContainsTaggedFields(t, measurement, fields, tags)
}

func TestNoDevicesOutput(t *testing.T) {
	var acc testutil.Accumulator
	var plugin = &DMCache{
		PerDevice: true,
		getCurrentStatus: func() ([]string, error) {
			return []string{}, nil
		},
	}

	err := plugin.Gather(&acc)
	require.NoError(t, err)
}

func TestErrorDuringGettingStatus(t *testing.T) {
	var acc testutil.Accumulator
	var plugin = &DMCache{
		PerDevice: true,
		getCurrentStatus: func() ([]string, error) {
			return nil, errors.New("dmsetup doesn't exist")
		},
	}

	err := plugin.Gather(&acc)
	require.Error(t, err)
}

func TestBadFormatOfStatus(t *testing.T) {
	var acc testutil.Accumulator
	var plugin = &DMCache{
		PerDevice: true,
		getCurrentStatus: func() ([]string, error) {
			return badFormatOutput, nil
		},
	}

	err := plugin.Gather(&acc)
	require.Error(t, err)
}