package system

import (
	"fmt"
	"reflect"
	"testing"

	"github.com/influxdb/telegraf/testutil"
	"github.com/shirou/gopsutil/cpu"
	"github.com/shirou/gopsutil/disk"
	"github.com/shirou/gopsutil/mem"
	"github.com/shirou/gopsutil/net"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestSystemStats_GenerateStats(t *testing.T) {
	var mps MockPS

	defer mps.AssertExpectations(t)

	var acc testutil.Accumulator

	cts := cpu.CPUTimesStat{
		CPU:       "cpu0",
		User:      3.1,
		System:    8.2,
		Idle:      80.1,
		Nice:      1.3,
		Iowait:    0.2,
		Irq:       0.1,
		Softirq:   0.11,
		Steal:     0.0511,
		Guest:     8.1,
		GuestNice: 0.324,
	}

	cts2 := cpu.CPUTimesStat{
		CPU:       "cpu0",
		User:      11.4,     // increased by 8.3
		System:    10.9,     // increased by 2.7
		Idle:      158.8699, // increased by 78.7699 (for total increase of 100)
		Nice:      2.5,      // increased by 1.2
		Iowait:    0.7,      // increased by 0.5
		Irq:       1.2,      // increased by 1.1
		Softirq:   0.31,     // increased by 0.2
		Steal:     0.2812,   // increased by 0.0001
		Guest:     12.9,     // increased by 4.8
		GuestNice: 2.524,    // increased by 2.2
	}

	mps.On("CPUTimes").Return([]cpu.CPUTimesStat{cts}, nil)

	du := &disk.DiskUsageStat{
		Path:        "/",
		Fstype:      "ext4",
		Total:       128,
		Free:        23,
		InodesTotal: 1234,
		InodesFree:  234,
	}

	mps.On("DiskUsage").Return([]*disk.DiskUsageStat{du}, nil)

	diskio := disk.DiskIOCountersStat{
		ReadCount:    888,
		WriteCount:   5341,
		ReadBytes:    100000,
		WriteBytes:   200000,
		ReadTime:     7123,
		WriteTime:    9087,
		Name:         "sda1",
		IoTime:       123552,
		SerialNumber: "ab-123-ad",
	}

	mps.On("DiskIO").Return(map[string]disk.DiskIOCountersStat{"sda1": diskio}, nil)

	netio := net.NetIOCountersStat{
		Name:        "eth0",
		BytesSent:   1123,
		BytesRecv:   8734422,
		PacketsSent: 781,
		PacketsRecv: 23456,
		Errin:       832,
		Errout:      8,
		Dropin:      7,
		Dropout:     1,
	}

	mps.On("NetIO").Return([]net.NetIOCountersStat{netio}, nil)

	vms := &mem.VirtualMemoryStat{
		Total:       12400,
		Available:   7600,
		Used:        5000,
		UsedPercent: 47.1,
		Free:        1235,
		Active:      8134,
		Inactive:    1124,
		Buffers:     771,
		Cached:      4312,
		Wired:       134,
		Shared:      2142,
	}

	mps.On("VMStat").Return(vms, nil)

	sms := &mem.SwapMemoryStat{
		Total:       8123,
		Used:        1232,
		Free:        6412,
		UsedPercent: 12.2,
		Sin:         7,
		Sout:        830,
	}

	mps.On("SwapStat").Return(sms, nil)

	cs := NewCPUStats(&mps)

	cputags := map[string]string{
		"cpu": "cpu0",
	}

	preCPUPoints := len(acc.Points)
	err := cs.Gather(&acc)
	require.NoError(t, err)
	numCPUPoints := len(acc.Points) - preCPUPoints

	expectedCPUPoints := 10
	assert.Equal(t, numCPUPoints, expectedCPUPoints)

	// Computed values are checked with delta > 0 becasue of floating point arithmatic
	// imprecision
	assertContainsTaggedFloat(t, acc, "user", 3.1, 0, cputags)
	assertContainsTaggedFloat(t, acc, "system", 8.2, 0, cputags)
	assertContainsTaggedFloat(t, acc, "idle", 80.1, 0, cputags)
	assertContainsTaggedFloat(t, acc, "nice", 1.3, 0, cputags)
	assertContainsTaggedFloat(t, acc, "iowait", 0.2, 0, cputags)
	assertContainsTaggedFloat(t, acc, "irq", 0.1, 0, cputags)
	assertContainsTaggedFloat(t, acc, "softirq", 0.11, 0, cputags)
	assertContainsTaggedFloat(t, acc, "steal", 0.0511, 0, cputags)
	assertContainsTaggedFloat(t, acc, "guest", 8.1, 0, cputags)
	assertContainsTaggedFloat(t, acc, "guest_nice", 0.324, 0, cputags)

	mps2 := MockPS{}
	mps2.On("CPUTimes").Return([]cpu.CPUTimesStat{cts2}, nil)
	cs.ps = &mps2

	// Should have added cpu percentages too
	err = cs.Gather(&acc)
	require.NoError(t, err)

	numCPUPoints = len(acc.Points) - (preCPUPoints + numCPUPoints)
	expectedCPUPoints = 20
	assert.Equal(t, numCPUPoints, expectedCPUPoints)

	assertContainsTaggedFloat(t, acc, "user", 11.4, 0, cputags)
	assertContainsTaggedFloat(t, acc, "system", 10.9, 0, cputags)
	assertContainsTaggedFloat(t, acc, "idle", 158.8699, 0, cputags)
	assertContainsTaggedFloat(t, acc, "nice", 2.5, 0, cputags)
	assertContainsTaggedFloat(t, acc, "iowait", 0.7, 0, cputags)
	assertContainsTaggedFloat(t, acc, "irq", 1.2, 0, cputags)
	assertContainsTaggedFloat(t, acc, "softirq", 0.31, 0, cputags)
	assertContainsTaggedFloat(t, acc, "steal", 0.2812, 0, cputags)
	assertContainsTaggedFloat(t, acc, "guest", 12.9, 0, cputags)
	assertContainsTaggedFloat(t, acc, "guest_nice", 2.524, 0, cputags)

	assertContainsTaggedFloat(t, acc, "usage_user", 8.3, 0.0005, cputags)
	assertContainsTaggedFloat(t, acc, "usage_system", 2.7, 0.0005, cputags)
	assertContainsTaggedFloat(t, acc, "usage_idle", 78.7699, 0.0005, cputags)
	assertContainsTaggedFloat(t, acc, "usage_nice", 1.2, 0.0005, cputags)
	assertContainsTaggedFloat(t, acc, "usage_iowait", 0.5, 0.0005, cputags)
	assertContainsTaggedFloat(t, acc, "usage_irq", 1.1, 0.0005, cputags)
	assertContainsTaggedFloat(t, acc, "usage_softirq", 0.2, 0.0005, cputags)
	assertContainsTaggedFloat(t, acc, "usage_steal", 0.2301, 0.0005, cputags)
	assertContainsTaggedFloat(t, acc, "usage_guest", 4.8, 0.0005, cputags)
	assertContainsTaggedFloat(t, acc, "usage_guest_nice", 2.2, 0.0005, cputags)

	err = (&DiskStats{&mps}).Gather(&acc)
	require.NoError(t, err)

	tags := map[string]string{
		"path":   "/",
		"fstype": "ext4",
	}

	assert.True(t, acc.CheckTaggedValue("total", uint64(128), tags))
	assert.True(t, acc.CheckTaggedValue("used", uint64(105), tags))
	assert.True(t, acc.CheckTaggedValue("free", uint64(23), tags))
	assert.True(t, acc.CheckTaggedValue("inodes_total", uint64(1234), tags))
	assert.True(t, acc.CheckTaggedValue("inodes_free", uint64(234), tags))
	assert.True(t, acc.CheckTaggedValue("inodes_used", uint64(1000), tags))

	err = (&NetIOStats{ps: &mps, skipChecks: true}).Gather(&acc)
	require.NoError(t, err)

	ntags := map[string]string{
		"interface": "eth0",
	}

	assert.NoError(t, acc.ValidateTaggedValue("bytes_sent", uint64(1123), ntags))
	assert.NoError(t, acc.ValidateTaggedValue("bytes_recv", uint64(8734422), ntags))
	assert.NoError(t, acc.ValidateTaggedValue("packets_sent", uint64(781), ntags))
	assert.NoError(t, acc.ValidateTaggedValue("packets_recv", uint64(23456), ntags))
	assert.NoError(t, acc.ValidateTaggedValue("err_in", uint64(832), ntags))
	assert.NoError(t, acc.ValidateTaggedValue("err_out", uint64(8), ntags))
	assert.NoError(t, acc.ValidateTaggedValue("drop_in", uint64(7), ntags))
	assert.NoError(t, acc.ValidateTaggedValue("drop_out", uint64(1), ntags))

	err = (&DiskIOStats{&mps}).Gather(&acc)
	require.NoError(t, err)

	dtags := map[string]string{
		"name":   "sda1",
		"serial": "ab-123-ad",
	}

	assert.True(t, acc.CheckTaggedValue("reads", uint64(888), dtags))
	assert.True(t, acc.CheckTaggedValue("writes", uint64(5341), dtags))
	assert.True(t, acc.CheckTaggedValue("read_bytes", uint64(100000), dtags))
	assert.True(t, acc.CheckTaggedValue("write_bytes", uint64(200000), dtags))
	assert.True(t, acc.CheckTaggedValue("read_time", uint64(7123), dtags))
	assert.True(t, acc.CheckTaggedValue("write_time", uint64(9087), dtags))
	assert.True(t, acc.CheckTaggedValue("io_time", uint64(123552), dtags))

	err = (&MemStats{&mps}).Gather(&acc)
	require.NoError(t, err)

	vmtags := map[string]string(nil)

	assert.True(t, acc.CheckTaggedValue("total", uint64(12400), vmtags))
	assert.True(t, acc.CheckTaggedValue("available", uint64(7600), vmtags))
	assert.True(t, acc.CheckTaggedValue("used", uint64(5000), vmtags))
	assert.True(t, acc.CheckTaggedValue("used_perc", float64(47.1), vmtags))
	assert.True(t, acc.CheckTaggedValue("free", uint64(1235), vmtags))
	assert.True(t, acc.CheckTaggedValue("active", uint64(8134), vmtags))
	assert.True(t, acc.CheckTaggedValue("inactive", uint64(1124), vmtags))
	assert.True(t, acc.CheckTaggedValue("buffers", uint64(771), vmtags))
	assert.True(t, acc.CheckTaggedValue("cached", uint64(4312), vmtags))
	assert.True(t, acc.CheckTaggedValue("wired", uint64(134), vmtags))
	assert.True(t, acc.CheckTaggedValue("shared", uint64(2142), vmtags))

	acc.Points = nil

	err = (&SwapStats{&mps}).Gather(&acc)
	require.NoError(t, err)

	swaptags := map[string]string(nil)

	assert.NoError(t, acc.ValidateTaggedValue("total", uint64(8123), swaptags))
	assert.NoError(t, acc.ValidateTaggedValue("used", uint64(1232), swaptags))
	assert.NoError(t, acc.ValidateTaggedValue("used_perc", float64(12.2), swaptags))
	assert.NoError(t, acc.ValidateTaggedValue("free", uint64(6412), swaptags))
	assert.NoError(t, acc.ValidateTaggedValue("in", uint64(7), swaptags))
	assert.NoError(t, acc.ValidateTaggedValue("out", uint64(830), swaptags))
}

// Asserts that a given accumulator contains a measurment of type float64 with
// specific tags within a certain distance of a given expected value. Asserts a failure
// if the measurement is of the wrong type, or if no matching measurements are found
//
// Paramaters:
//     t *testing.T            : Testing object to use
//     acc testutil.Accumulator: Accumulator to examine
//     measurement string      : Name of the measurement to examine
//     expectedValue float64   : Value to search for within the measurement
//     delta float64           : Maximum acceptable distance of an accumulated value
//                               from the expectedValue parameter. Useful when
//                               floating-point arithmatic imprecision makes looking
//                               for an exact match impractical
//     tags map[string]string  : Tag set the found measurement must have. Set to nil to
//                               ignore the tag set.
func assertContainsTaggedFloat(
	t *testing.T,
	acc testutil.Accumulator,
	measurement string,
	expectedValue float64,
	delta float64,
	tags map[string]string,
) {
	var actualValue float64
	for _, pt := range acc.Points {
		if pt.Measurement == measurement {
			if (tags == nil) || reflect.DeepEqual(pt.Tags, tags) {
				if value, ok := pt.Values["value"].(float64); ok {
					actualValue = value
					if (value >= expectedValue-delta) && (value <= expectedValue+delta) {
						// Found the point, return without failing
						return
					}
				} else {
					assert.Fail(t, fmt.Sprintf("Measurement \"%s\" does not have type float64",
						measurement))
				}

			}
		}
	}
	msg := fmt.Sprintf("Could not find measurement \"%s\" with requested tags within %f of %f, Actual: %f",
		measurement, delta, expectedValue, actualValue)
	assert.Fail(t, msg)
}