// Copyright 2021 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//go:build !noethtool
// +build !noethtool

package collector

import (
	"bufio"
	"fmt"
	"io"
	"log/slog"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"syscall"
	"testing"

	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/testutil"
	"github.com/safchain/ethtool"
	"golang.org/x/sys/unix"
)

type EthtoolFixture struct {
	fixturePath string
}

type testEthtoolCollector struct {
	dsc Collector
}

func (c testEthtoolCollector) Collect(ch chan<- prometheus.Metric) {
	c.dsc.Update(ch)
}

func (c testEthtoolCollector) Describe(ch chan<- *prometheus.Desc) {
	prometheus.DescribeByCollect(c, ch)
}

func NewTestEthtoolCollector(logger *slog.Logger) (prometheus.Collector, error) {
	dsc, err := NewEthtoolTestCollector(logger)
	if err != nil {
		return testEthtoolCollector{}, err
	}
	return testEthtoolCollector{
		dsc: dsc,
	}, err
}

func (e *EthtoolFixture) DriverInfo(intf string) (ethtool.DrvInfo, error) {
	res := ethtool.DrvInfo{}

	fixtureFile, err := os.Open(filepath.Join(e.fixturePath, intf, "driver"))
	if e, ok := err.(*os.PathError); ok && e.Err == syscall.ENOENT {
		// The fixture for this interface doesn't exist. Translate that to unix.EOPNOTSUPP
		// to replicate an interface that doesn't support ethtool driver info
		return res, unix.EOPNOTSUPP
	}
	if err != nil {
		return res, err
	}
	defer fixtureFile.Close()

	scanner := bufio.NewScanner(fixtureFile)
	for scanner.Scan() {
		line := scanner.Text()
		if strings.HasPrefix(line, "#") {
			continue
		}
		line = strings.Trim(line, " ")
		items := strings.Split(line, ": ")
		switch items[0] {
		case "driver":
			res.Driver = items[1]
		case "version":
			res.Version = items[1]
		case "firmware-version":
			res.FwVersion = items[1]
		case "bus-info":
			res.BusInfo = items[1]
		case "expansion-rom-version":
			res.EromVersion = items[1]
		}
	}

	return res, err
}

func (e *EthtoolFixture) Stats(intf string) (map[string]uint64, error) {
	res := make(map[string]uint64)

	fixtureFile, err := os.Open(filepath.Join(e.fixturePath, intf, "statistics"))
	if e, ok := err.(*os.PathError); ok && e.Err == syscall.ENOENT {
		// The fixture for this interface doesn't exist. Translate that to unix.EOPNOTSUPP
		// to replicate an interface that doesn't support ethtool stats
		return res, unix.EOPNOTSUPP
	}
	if err != nil {
		return res, err
	}
	defer fixtureFile.Close()

	scanner := bufio.NewScanner(fixtureFile)
	for scanner.Scan() {
		line := scanner.Text()
		if strings.HasPrefix(line, "#") {
			continue
		}
		if strings.HasPrefix(line, "NIC statistics:") {
			continue
		}
		line = strings.Trim(line, " ")
		items := strings.Split(line, ": ")
		val, err := strconv.ParseUint(items[1], 10, 64)
		if err != nil {
			return res, err
		}
		if items[0] == "ERROR" {
			return res, unix.Errno(val)
		}
		res[items[0]] = val
	}

	return res, err
}

func readModes(modes string) uint32 {
	var out uint32
	for _, mode := range strings.Split(modes, " ") {
		switch mode {
		case "10baseT/Half":
			out |= (1 << unix.ETHTOOL_LINK_MODE_10baseT_Half_BIT)
		case "10baseT/Full":
			out |= (1 << unix.ETHTOOL_LINK_MODE_10baseT_Full_BIT)
		case "100baseT/Half":
			out |= (1 << unix.ETHTOOL_LINK_MODE_100baseT_Half_BIT)
		case "100baseT/Full":
			out |= (1 << unix.ETHTOOL_LINK_MODE_100baseT_Full_BIT)
		case "1000baseT/Half":
			out |= (1 << unix.ETHTOOL_LINK_MODE_1000baseT_Half_BIT)
		case "1000baseT/Full":
			out |= (1 << unix.ETHTOOL_LINK_MODE_1000baseT_Full_BIT)
		case "10000baseT/Full":
			out |= (1 << unix.ETHTOOL_LINK_MODE_10000baseT_Full_BIT)
		}
	}
	return out
}

func readPortTypes(portTypes string) uint32 {
	var out uint32
	for _, ptype := range strings.Split(portTypes, " ") {
		ptype = strings.Trim(ptype, " \t")
		if ptype == "TP" {
			out |= (1 << unix.ETHTOOL_LINK_MODE_TP_BIT)
		}
		if ptype == "MII" {
			out |= (1 << unix.ETHTOOL_LINK_MODE_MII_BIT)
		}
	}
	return out
}

func (e *EthtoolFixture) LinkInfo(intf string) (ethtool.EthtoolCmd, error) {
	var res ethtool.EthtoolCmd
	fixtureFile, err := os.Open(filepath.Join(e.fixturePath, intf, "settings"))
	if e, ok := err.(*os.PathError); ok && e.Err == syscall.ENOENT {
		// The fixture for this interface doesn't exist. Translate that to unix.EOPNOTSUPP
		// to replicate an interface that doesn't support ethtool stats
		return res, unix.EOPNOTSUPP
	}
	if err != nil {
		return res, err
	}
	defer fixtureFile.Close()

	scanner := bufio.NewScanner(fixtureFile)
	readingSupportedLinkModes := false
	readingAdvertisedLinkModes := false
	for scanner.Scan() {
		line := scanner.Text()
		if strings.HasPrefix(line, "#") || strings.HasPrefix(line, "Settings for") {
			continue
		}
		line = strings.Trim(line, " \t")

		if (readingAdvertisedLinkModes || readingSupportedLinkModes) && strings.Contains(line, ":") {
			readingAdvertisedLinkModes = false
			readingSupportedLinkModes = false
		}

		if readingAdvertisedLinkModes {
			res.Advertising |= readModes(line)
			continue
		} else if readingSupportedLinkModes {
			res.Supported |= readModes(line)
			continue
		}

		items := strings.Split(line, ": ")
		if items[0] == "Supported pause frame use" {
			if items[1] == "Symmetric" {
				res.Supported |= (1 << unix.ETHTOOL_LINK_MODE_Pause_BIT)
			} else if items[1] == "Receive-only" {
				res.Supported |= (1 << unix.ETHTOOL_LINK_MODE_Asym_Pause_BIT)
			}
		}
		if items[0] == "Advertised pause frame use" {
			if items[1] == "Symmetric" {
				res.Advertising |= (1 << unix.ETHTOOL_LINK_MODE_Pause_BIT)
			} else if items[1] == "Receive-only" {
				res.Advertising |= (1 << unix.ETHTOOL_LINK_MODE_Asym_Pause_BIT)
			}
		}
		if items[0] == "Supported ports" {
			res.Supported |= readPortTypes(items[1])
		}
		if items[0] == "Supported link modes" {
			res.Supported |= readModes(items[1])
			readingSupportedLinkModes = true
		}
		if items[0] == "Advertised link modes" {
			res.Advertising |= readModes(items[1])
			readingAdvertisedLinkModes = true
		}
		if items[0] == "Supports auto-negotiation" {
			if items[1] == "Yes" {
				res.Supported |= (1 << unix.ETHTOOL_LINK_MODE_Autoneg_BIT)
			}
		}
		if items[0] == "Advertised auto-negotiation" {
			if items[1] == "Yes" {
				res.Advertising |= (1 << unix.ETHTOOL_LINK_MODE_Autoneg_BIT)
			}
		}
		if items[0] == "Auto-negotiation" {
			if items[1] == "on" {
				res.Autoneg = 1
			}
		}
	}

	return res, err
}

func NewEthtoolTestCollector(logger *slog.Logger) (Collector, error) {
	collector, err := makeEthtoolCollector(logger)
	if err != nil {
		return nil, err
	}
	collector.ethtool = &EthtoolFixture{
		fixturePath: "fixtures/ethtool/",
	}
	return collector, nil
}

func TestBuildEthtoolFQName(t *testing.T) {
	testcases := map[string]string{
		"rx_errors":                    "node_ethtool_received_errors",
		"Queue[0] AllocFails":          "node_ethtool_queue_0_allocfails",
		"Tx LPI entry count":           "node_ethtool_transmitted_lpi_entry_count",
		"port.VF_admin_queue_requests": "node_ethtool_port_vf_admin_queue_requests",
		"[3]: tx_bytes":                "node_ethtool_3_transmitted_bytes",
		"     err":                     "node_ethtool_err",
	}

	for metric, expected := range testcases {
		got := buildEthtoolFQName(metric)
		if expected != got {
			t.Errorf("Expected '%s' but got '%s'", expected, got)
		}
	}
}

func TestEthToolCollector(t *testing.T) {
	testcase := `# HELP node_ethtool_align_errors Network interface align_errors
# TYPE node_ethtool_align_errors untyped
node_ethtool_align_errors{device="eth0"} 0
# HELP node_ethtool_info A metric with a constant '1' value labeled by bus_info, device, driver, expansion_rom_version, firmware_version, version.
# TYPE node_ethtool_info gauge
node_ethtool_info{bus_info="0000:00:1f.6",device="eth0",driver="e1000e",expansion_rom_version="",firmware_version="0.5-4",version="5.11.0-22-generic"} 1
# HELP node_ethtool_received_broadcast Network interface rx_broadcast
# TYPE node_ethtool_received_broadcast untyped
node_ethtool_received_broadcast{device="eth0"} 5792
# HELP node_ethtool_received_errors_total Number of received frames with errors
# TYPE node_ethtool_received_errors_total untyped
node_ethtool_received_errors_total{device="eth0"} 0
# HELP node_ethtool_received_missed Network interface rx_missed
# TYPE node_ethtool_received_missed untyped
node_ethtool_received_missed{device="eth0"} 401
# HELP node_ethtool_received_multicast Network interface rx_multicast
# TYPE node_ethtool_received_multicast untyped
node_ethtool_received_multicast{device="eth0"} 23973
# HELP node_ethtool_received_packets_total Network interface packets received
# TYPE node_ethtool_received_packets_total untyped
node_ethtool_received_packets_total{device="eth0"} 1.260062e+06
# HELP node_ethtool_received_unicast Network interface rx_unicast
# TYPE node_ethtool_received_unicast untyped
node_ethtool_received_unicast{device="eth0"} 1.230297e+06
# HELP node_ethtool_transmitted_aborted Network interface tx_aborted
# TYPE node_ethtool_transmitted_aborted untyped
node_ethtool_transmitted_aborted{device="eth0"} 0
# HELP node_ethtool_transmitted_errors_total Number of sent frames with errors
# TYPE node_ethtool_transmitted_errors_total untyped
node_ethtool_transmitted_errors_total{device="eth0"} 0
# HELP node_ethtool_transmitted_multi_collisions Network interface tx_multi_collisions
# TYPE node_ethtool_transmitted_multi_collisions untyped
node_ethtool_transmitted_multi_collisions{device="eth0"} 0
# HELP node_ethtool_transmitted_packets_total Network interface packets sent
# TYPE node_ethtool_transmitted_packets_total untyped
node_ethtool_transmitted_packets_total{device="eth0"} 961500
# HELP node_ethtool_transmitted_single_collisions Network interface tx_single_collisions
# TYPE node_ethtool_transmitted_single_collisions untyped
node_ethtool_transmitted_single_collisions{device="eth0"} 0
# HELP node_ethtool_transmitted_underrun Network interface tx_underrun
# TYPE node_ethtool_transmitted_underrun untyped
node_ethtool_transmitted_underrun{device="eth0"} 0
# HELP node_network_advertised_speed_bytes Combination of speeds and features offered by network device
# TYPE node_network_advertised_speed_bytes gauge
node_network_advertised_speed_bytes{device="eth0",duplex="full",mode="1000baseT"} 1.25e+08
node_network_advertised_speed_bytes{device="eth0",duplex="full",mode="100baseT"} 1.25e+07
node_network_advertised_speed_bytes{device="eth0",duplex="full",mode="10baseT"} 1.25e+06
node_network_advertised_speed_bytes{device="eth0",duplex="half",mode="100baseT"} 1.25e+07
node_network_advertised_speed_bytes{device="eth0",duplex="half",mode="10baseT"} 1.25e+06
# HELP node_network_asymmetricpause_advertised If this port device offers asymmetric pause capability
# TYPE node_network_asymmetricpause_advertised gauge
node_network_asymmetricpause_advertised{device="eth0"} 0
# HELP node_network_asymmetricpause_supported If this port device supports asymmetric pause frames
# TYPE node_network_asymmetricpause_supported gauge
node_network_asymmetricpause_supported{device="eth0"} 0
# HELP node_network_autonegotiate If this port is using autonegotiate
# TYPE node_network_autonegotiate gauge
node_network_autonegotiate{device="eth0"} 1
# HELP node_network_autonegotiate_advertised If this port device offers autonegotiate
# TYPE node_network_autonegotiate_advertised gauge
node_network_autonegotiate_advertised{device="eth0"} 1
# HELP node_network_autonegotiate_supported If this port device supports autonegotiate
# TYPE node_network_autonegotiate_supported gauge
node_network_autonegotiate_supported{device="eth0"} 1
# HELP node_network_pause_advertised If this port device offers pause capability
# TYPE node_network_pause_advertised gauge
node_network_pause_advertised{device="eth0"} 1
# HELP node_network_pause_supported If this port device supports pause frames
# TYPE node_network_pause_supported gauge
node_network_pause_supported{device="eth0"} 1
# HELP node_network_supported_port_info Type of ports or PHYs supported by network device
# TYPE node_network_supported_port_info gauge
node_network_supported_port_info{device="eth0",type="MII"} 1
node_network_supported_port_info{device="eth0",type="TP"} 1
# HELP node_network_supported_speed_bytes Combination of speeds and features supported by network device
# TYPE node_network_supported_speed_bytes gauge
node_network_supported_speed_bytes{device="eth0",duplex="full",mode="10000baseT"} 1.25e+09
node_network_supported_speed_bytes{device="eth0",duplex="full",mode="1000baseT"} 1.25e+08
node_network_supported_speed_bytes{device="eth0",duplex="full",mode="100baseT"} 1.25e+07
node_network_supported_speed_bytes{device="eth0",duplex="full",mode="10baseT"} 1.25e+06
node_network_supported_speed_bytes{device="eth0",duplex="half",mode="100baseT"} 1.25e+07
node_network_supported_speed_bytes{device="eth0",duplex="half",mode="10baseT"} 1.25e+06
`
	*sysPath = "fixtures/sys"

	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
	collector, err := NewEthtoolTestCollector(logger)
	if err != nil {
		t.Fatal(err)
	}
	c, err := NewTestEthtoolCollector(logger)
	if err != nil {
		t.Fatal(err)
	}
	reg := prometheus.NewRegistry()
	reg.MustRegister(c)

	sink := make(chan prometheus.Metric)
	go func() {
		err = collector.Update(sink)
		if err != nil {
			panic(fmt.Errorf("failed to update collector: %s", err))
		}
		close(sink)
	}()

	err = testutil.GatherAndCompare(reg, strings.NewReader(testcase))
	if err != nil {
		t.Fatal(err)
	}
}