package util

import (
	"fmt"
	"os"
	"path/filepath"
	"runtime"
	"strconv"
	"strings"

	"github.com/mndrix/tap-go"
	rspec "github.com/opencontainers/runtime-spec/specs-go"
	"github.com/opencontainers/runtime-tools/cgroups"
)

const (
	// CPUCgroupPrefix is default path prefix where CPU cgroups are created
	CPUCgroupPrefix string = "/sys/fs/cgroup/cpu,cpuacct"
)

// ValidateLinuxResourcesCPU validates if Linux.Resources.CPU is set to
// correct values, the same as given values in the config.
func ValidateLinuxResourcesCPU(config *rspec.Spec, t *tap.T, state *rspec.State) error {
	cg, err := cgroups.FindCgroup()
	t.Ok((err == nil), "find cpu cgroup")
	if err != nil {
		t.Diagnostic(err.Error())
		return nil
	}

	lcd, err := cg.GetCPUData(state.Pid, config.Linux.CgroupsPath)
	t.Ok((err == nil), "get cpu cgroup data")
	if err != nil {
		t.Diagnostic(err.Error())
		return nil
	}

	if lcd.Shares == nil || config.Linux.Resources.CPU.Shares == nil {
		t.Diagnostic(fmt.Sprintf("unable to get cpu shares, lcd.Shares == %v, config.Linux.Resources.CPU.Shares == %v", lcd.Shares, config.Linux.Resources.CPU.Shares))
		return nil
	}
	t.Ok(*lcd.Shares == *config.Linux.Resources.CPU.Shares, "cpu shares is set correctly")
	t.Diagnosticf("expect: %d, actual: %d", *config.Linux.Resources.CPU.Shares, *lcd.Shares)

	if lcd.Period == nil || config.Linux.Resources.CPU.Period == nil {
		t.Diagnostic(fmt.Sprintf("unable to get cpu period, lcd.Period == %v, config.Linux.Resources.CPU.Period == %v", lcd.Period, config.Linux.Resources.CPU.Period))
		return nil
	}
	t.Ok(*lcd.Period == *config.Linux.Resources.CPU.Period, "cpu period is set correctly")
	t.Diagnosticf("expect: %d, actual: %d", *config.Linux.Resources.CPU.Period, *lcd.Period)

	if lcd.Quota == nil || config.Linux.Resources.CPU.Quota == nil {
		t.Diagnostic(fmt.Sprintf("unable to get cpu quota, lcd.Quota == %v, config.Linux.Resources.CPU.Quota == %v", lcd.Quota, config.Linux.Resources.CPU.Quota))
		return nil
	}
	t.Ok(*lcd.Quota == *config.Linux.Resources.CPU.Quota, "cpu quota is set correctly")
	t.Diagnosticf("expect: %d, actual: %d", *config.Linux.Resources.CPU.Quota, *lcd.Quota)

	t.Ok(lcd.Cpus == config.Linux.Resources.CPU.Cpus, "cpu cpus is set correctly")
	t.Diagnosticf("expect: %s, actual: %s", config.Linux.Resources.CPU.Cpus, lcd.Cpus)

	t.Ok(lcd.Mems == config.Linux.Resources.CPU.Mems, "cpu mems is set correctly")
	t.Diagnosticf("expect: %s, actual: %s", config.Linux.Resources.CPU.Mems, lcd.Mems)

	return nil
}

// ValidateLinuxResourcesCPUEmpty validates Linux.Resources.CPU is set to
// correct values, when each value are set to the default ones.
func ValidateLinuxResourcesCPUEmpty(config *rspec.Spec, t *tap.T, state *rspec.State) error {
	outShares, err := os.ReadFile(filepath.Join(CPUCgroupPrefix, "cpu.shares"))
	if err != nil {
		return nil
	}
	sh, _ := strconv.Atoi(strings.TrimSpace(string(outShares)))
	defaultShares := uint64(sh)

	outPeriod, err := os.ReadFile(filepath.Join(CPUCgroupPrefix, "cpu.cfs_period_us"))
	if err != nil {
		return nil
	}
	pe, _ := strconv.Atoi(strings.TrimSpace(string(outPeriod)))
	defaultPeriod := uint64(pe)

	outQuota, err := os.ReadFile(filepath.Join(CPUCgroupPrefix, "cpu.cfs_quota_us"))
	if err != nil {
		return nil
	}
	qu, _ := strconv.Atoi(strings.TrimSpace(string(outQuota)))
	defaultQuota := int64(qu)

	defaultCpus := fmt.Sprintf("0-%d", runtime.NumCPU()-1)
	defaultMems := "0"

	cg, err := cgroups.FindCgroup()
	t.Ok((err == nil), "find cpu cgroup")
	if err != nil {
		t.Diagnostic(err.Error())
		return nil
	}

	lcd, err := cg.GetCPUData(state.Pid, config.Linux.CgroupsPath)
	t.Ok((err == nil), "get cpu cgroup data")
	if err != nil {
		t.Diagnostic(err.Error())
		return nil
	}

	if lcd.Shares == nil {
		t.Diagnostic(fmt.Sprintf("unable to get cpu shares, lcd.Shares == %v", lcd.Shares))
		return nil
	}
	t.Ok(*lcd.Shares == defaultShares, "cpu shares is set correctly")
	t.Diagnosticf("expect: %d, actual: %d", defaultShares, *lcd.Shares)

	if lcd.Period == nil {
		t.Diagnostic(fmt.Sprintf("unable to get cpu period, lcd.Period == %v", lcd.Period))
		return nil
	}
	t.Ok(*lcd.Period == defaultPeriod, "cpu period is set correctly")
	t.Diagnosticf("expect: %d, actual: %d", defaultPeriod, *lcd.Period)

	if lcd.Quota == nil {
		t.Diagnostic(fmt.Sprintf("unable to get cpu quota, lcd.Quota == %v", lcd.Quota))
		return nil
	}
	t.Ok(*lcd.Quota == defaultQuota, "cpu quota is set correctly")
	t.Diagnosticf("expect: %d, actual: %d", defaultQuota, *lcd.Quota)

	t.Ok(lcd.Cpus == defaultCpus, "cpu cpus is set correctly")
	t.Diagnosticf("expect: %s, actual: %s", defaultCpus, lcd.Cpus)

	t.Ok(lcd.Mems == defaultMems, "cpu mems is set correctly")
	t.Diagnosticf("expect: %s, actual: %s", defaultMems, lcd.Mems)

	return nil
}