// Copyright The Helm 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 exec

import (
	"bufio"
	"fmt"
	"io"
	"os"
	"os/exec"
	"strings"

	"github.com/helm/chart-testing/v3/pkg/util"
)

type ProcessExecutor struct {
	debug bool
}

func NewProcessExecutor(debug bool) ProcessExecutor {
	return ProcessExecutor{
		debug: debug,
	}
}

func (p ProcessExecutor) RunProcessAndCaptureOutput(executable string, execArgs ...interface{}) (string, error) {
	return p.RunProcessInDirAndCaptureOutput("", executable, execArgs)
}

func (p ProcessExecutor) RunProcessAndCaptureStdout(executable string, execArgs ...interface{}) (string, error) {
	return p.RunProcessInDirAndCaptureStdout("", executable, execArgs)
}

func (p ProcessExecutor) RunProcessInDirAndCaptureOutput(workingDirectory string, executable string, execArgs ...interface{}) (string, error) {
	cmd, err := p.CreateProcess(executable, execArgs...)
	if err != nil {
		return "", err
	}

	cmd.Dir = workingDirectory
	bytes, err := cmd.CombinedOutput()

	if err != nil {
		return "", fmt.Errorf("failed running process: %w", err)
	}
	return strings.TrimSpace(string(bytes)), nil
}

func (p ProcessExecutor) RunProcessInDirAndCaptureStdout(workingDirectory string, executable string, execArgs ...interface{}) (string, error) {
	cmd, err := p.CreateProcess(executable, execArgs...)
	if err != nil {
		return "", err
	}

	cmd.Dir = workingDirectory
	bytes, err := cmd.Output()

	if err != nil {
		return "", fmt.Errorf("failed running process: %w", err)
	}
	return strings.TrimSpace(string(bytes)), nil
}

func (p ProcessExecutor) RunProcess(executable string, execArgs ...interface{}) error {
	cmd, err := p.CreateProcess(executable, execArgs...)
	if err != nil {
		return err
	}

	outReader, err := cmd.StdoutPipe()
	if err != nil {
		return fmt.Errorf("failed getting StdoutPipe for command: %w", err)
	}

	errReader, err := cmd.StderrPipe()
	if err != nil {
		return fmt.Errorf("failed getting StderrPipe for command: %w", err)
	}

	scanner := bufio.NewScanner(io.MultiReader(outReader, errReader))
	go func() {
		defer outReader.Close()
		defer errReader.Close()
		for scanner.Scan() {
			fmt.Println(scanner.Text())
		}
	}()

	err = cmd.Start()
	if err != nil {
		return fmt.Errorf("failed running process: %w", err)
	}

	err = cmd.Wait()
	if err != nil {
		return fmt.Errorf("failed waiting for process: %w", err)
	}

	return nil
}

func (p ProcessExecutor) CreateProcess(executable string, execArgs ...interface{}) (*exec.Cmd, error) {
	args, err := util.Flatten(execArgs)
	if p.debug {
		fmt.Println(">>>", executable, strings.Join(args, " "))
	}
	if err != nil {
		return nil, fmt.Errorf("invalid arguments supplied: %w", err)
	}
	cmd := exec.Command(executable, args...)

	return cmd, nil
}

type fn func(port int) error

func (p ProcessExecutor) RunWithProxy(withProxy fn) error {
	randomPort, err := util.GetRandomPort()
	if err != nil {
		return fmt.Errorf("could not find a free port for running 'kubectl proxy': %w", err)
	}

	fmt.Printf("Running 'kubectl proxy' on port %d\n", randomPort)
	cmdProxy, err := p.CreateProcess("kubectl", "proxy", fmt.Sprintf("--port=%d", randomPort))
	if err != nil {
		return fmt.Errorf("failed creating the 'kubectl proxy' process: %w", err)
	}
	err = cmdProxy.Start()
	if err != nil {
		return fmt.Errorf("failed starting the 'kubectl proxy' process: %w", err)
	}

	err = withProxy(randomPort)

	_ = cmdProxy.Process.Signal(os.Kill)

	if err != nil {
		return fmt.Errorf("failed running command with proxy: %w", err)
	}

	return nil
}