/*
Copyright 2014 The Kubernetes 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.
*/

package kubectl

import (
	"bytes"
	"fmt"
	"io"
	"net"
	"net/url"
	"os"
	"os/exec"
	"strings"
	"syscall"
	"time"

	"k8s.io/client-go/tools/clientcmd"
	uexec "k8s.io/utils/exec"

	"k8s.io/kubernetes/test/e2e/framework"
)

// KubectlBuilder is used to build, customize and execute a kubectl Command.
// Add more functions to customize the builder as needed.
type KubectlBuilder struct {
	cmd     *exec.Cmd
	timeout <-chan time.Time
}

// NewKubectlCommand returns a KubectlBuilder for running kubectl.
func NewKubectlCommand(namespace string, args ...string) *KubectlBuilder {
	b := new(KubectlBuilder)
	tk := NewTestKubeconfig(framework.TestContext.CertDir, framework.TestContext.Host, framework.TestContext.KubeConfig, framework.TestContext.KubeContext, framework.TestContext.KubectlPath, namespace)
	b.cmd = tk.KubectlCmd(args...)
	return b
}

// AppendEnv appends the given environment and returns itself.
func (b *KubectlBuilder) AppendEnv(env []string) *KubectlBuilder {
	if b.cmd.Env == nil {
		b.cmd.Env = os.Environ()
	}
	b.cmd.Env = append(b.cmd.Env, env...)
	return b
}

// WithTimeout sets the given timeout and returns itself.
func (b *KubectlBuilder) WithTimeout(t <-chan time.Time) *KubectlBuilder {
	b.timeout = t
	return b
}

// WithStdinData sets the given data to stdin and returns itself.
func (b KubectlBuilder) WithStdinData(data string) *KubectlBuilder {
	b.cmd.Stdin = strings.NewReader(data)
	return &b
}

// WithStdinReader sets the given reader and returns itself.
func (b KubectlBuilder) WithStdinReader(reader io.Reader) *KubectlBuilder {
	b.cmd.Stdin = reader
	return &b
}

// ExecOrDie runs the kubectl executable or dies if error occurs.
func (b KubectlBuilder) ExecOrDie(namespace string) string {
	str, err := b.Exec()
	// In case of i/o timeout error, try talking to the apiserver again after 2s before dying.
	// Note that we're still dying after retrying so that we can get visibility to triage it further.
	if isTimeout(err) {
		framework.Logf("Hit i/o timeout error, talking to the server 2s later to see if it's temporary.")
		time.Sleep(2 * time.Second)
		retryStr, retryErr := RunKubectl(namespace, "version")
		framework.Logf("stdout: %q", retryStr)
		framework.Logf("err: %v", retryErr)
	}
	framework.ExpectNoError(err)
	return str
}

func isTimeout(err error) bool {
	switch err := err.(type) {
	case *url.Error:
		if err, ok := err.Err.(net.Error); ok && err.Timeout() {
			return true
		}
	case net.Error:
		if err.Timeout() {
			return true
		}
	}
	return false
}

// Exec runs the kubectl executable.
func (b KubectlBuilder) Exec() (string, error) {
	stdout, _, err := b.ExecWithFullOutput()
	return stdout, err
}

// ExecWithFullOutput runs the kubectl executable, and returns the stdout and stderr.
func (b KubectlBuilder) ExecWithFullOutput() (string, string, error) {
	var stdout, stderr bytes.Buffer
	cmd := b.cmd
	cmd.Stdout, cmd.Stderr = &stdout, &stderr

	framework.Logf("Running '%s %s'", cmd.Path, strings.Join(cmd.Args[1:], " ")) // skip arg[0] as it is printed separately
	if err := cmd.Start(); err != nil {
		return "", "", fmt.Errorf("error starting %v:\nCommand stdout:\n%v\nstderr:\n%v\nerror:\n%v", cmd, cmd.Stdout, cmd.Stderr, err)
	}
	errCh := make(chan error, 1)
	go func() {
		errCh <- cmd.Wait()
	}()
	select {
	case err := <-errCh:
		if err != nil {
			var rc = 127
			if ee, ok := err.(*exec.ExitError); ok {
				rc = int(ee.Sys().(syscall.WaitStatus).ExitStatus())
				framework.Logf("rc: %d", rc)
			}
			return stdout.String(), stderr.String(), uexec.CodeExitError{
				Err:  fmt.Errorf("error running %v:\nCommand stdout:\n%v\nstderr:\n%v\nerror:\n%v", cmd, cmd.Stdout, cmd.Stderr, err),
				Code: rc,
			}
		}
	case <-b.timeout:
		b.cmd.Process.Kill()
		return "", "", fmt.Errorf("timed out waiting for command %v:\nCommand stdout:\n%v\nstderr:\n%v", cmd, cmd.Stdout, cmd.Stderr)
	}
	framework.Logf("stderr: %q", stderr.String())
	framework.Logf("stdout: %q", stdout.String())
	return stdout.String(), stderr.String(), nil
}

// RunKubectlOrDie is a convenience wrapper over kubectlBuilder
func RunKubectlOrDie(namespace string, args ...string) string {
	return NewKubectlCommand(namespace, args...).ExecOrDie(namespace)
}

// RunKubectl is a convenience wrapper over kubectlBuilder
func RunKubectl(namespace string, args ...string) (string, error) {
	return NewKubectlCommand(namespace, args...).Exec()
}

// RunKubectlWithFullOutput is a convenience wrapper over kubectlBuilder
// It will also return the command's stderr.
func RunKubectlWithFullOutput(namespace string, args ...string) (string, string, error) {
	return NewKubectlCommand(namespace, args...).ExecWithFullOutput()
}

// RunKubectlOrDieInput is a convenience wrapper over kubectlBuilder that takes input to stdin
func RunKubectlOrDieInput(namespace string, data string, args ...string) string {
	return NewKubectlCommand(namespace, args...).WithStdinData(data).ExecOrDie(namespace)
}

// RunKubectlInput is a convenience wrapper over kubectlBuilder that takes input to stdin
func RunKubectlInput(namespace string, data string, args ...string) (string, error) {
	return NewKubectlCommand(namespace, args...).WithStdinData(data).Exec()
}

// RunKubemciWithKubeconfig is a convenience wrapper over RunKubemciCmd
func RunKubemciWithKubeconfig(args ...string) (string, error) {
	if framework.TestContext.KubeConfig != "" {
		args = append(args, "--"+clientcmd.RecommendedConfigPathFlag+"="+framework.TestContext.KubeConfig)
	}
	return RunKubemciCmd(args...)
}

// RunKubemciCmd is a convenience wrapper over kubectlBuilder to run kubemci.
// It assumes that kubemci exists in PATH.
func RunKubemciCmd(args ...string) (string, error) {
	// kubemci is assumed to be in PATH.
	kubemci := "kubemci"
	b := new(KubectlBuilder)
	args = append(args, "--gcp-project="+framework.TestContext.CloudConfig.ProjectID)

	b.cmd = exec.Command(kubemci, args...)
	return b.Exec()
}