package maven

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
	"strings"

	piperhttp "github.com/SAP/jenkins-library/pkg/http"
	"github.com/SAP/jenkins-library/pkg/log"
	"github.com/SAP/jenkins-library/pkg/piperutils"
)

// ExecuteOptions are used by Execute() to construct the Maven command line.
type ExecuteOptions struct {
	PomPath                     string   `json:"pomPath,omitempty"`
	ProjectSettingsFile         string   `json:"projectSettingsFile,omitempty"`
	GlobalSettingsFile          string   `json:"globalSettingsFile,omitempty"`
	M2Path                      string   `json:"m2Path,omitempty"`
	Goals                       []string `json:"goals,omitempty"`
	Defines                     []string `json:"defines,omitempty"`
	Flags                       []string `json:"flags,omitempty"`
	LogSuccessfulMavenTransfers bool     `json:"logSuccessfulMavenTransfers,omitempty"`
	ReturnStdout                bool     `json:"returnStdout,omitempty"`
}

// EvaluateOptions are used by Evaluate() to construct the Maven command line.
// In contrast to ExecuteOptions, fewer settings are required for Evaluate and thus a separate type is needed.
type EvaluateOptions struct {
	PomPath             string `json:"pomPath,omitempty"`
	ProjectSettingsFile string `json:"projectSettingsFile,omitempty"`
	GlobalSettingsFile  string `json:"globalSettingsFile,omitempty"`
	M2Path              string `json:"m2Path,omitempty"`
}

type mavenExecRunner interface {
	Stdout(out io.Writer)
	Stderr(err io.Writer)
	RunExecutable(e string, p ...string) error
}

type mavenUtils interface {
	FileExists(path string) (bool, error)
	DownloadFile(url, filename string, header http.Header, cookies []*http.Cookie) error
}

type utilsBundle struct {
	*piperhttp.Client
	*piperutils.Files
}

func newUtils() *utilsBundle {
	return &utilsBundle{
		Client: &piperhttp.Client{},
		Files:  &piperutils.Files{},
	}
}

const mavenExecutable = "mvn"

// Execute constructs a mvn command line from the given options, and uses the provided
// mavenExecRunner to execute it.
func Execute(options *ExecuteOptions, command mavenExecRunner) (string, error) {
	stdOutBuf, stdOut := evaluateStdOut(options)
	command.Stdout(stdOut)
	command.Stderr(log.Writer())

	parameters, err := getParametersFromOptions(options, newUtils())
	if err != nil {
		return "", fmt.Errorf("failed to construct parameters from options: %w", err)
	}

	err = command.RunExecutable(mavenExecutable, parameters...)
	if err != nil {
		commandLine := append([]string{mavenExecutable}, parameters...)
		return "", fmt.Errorf("failed to run executable, command: '%s', error: %w", commandLine, err)
	}

	if stdOutBuf == nil {
		return "", nil
	}
	return string(stdOutBuf.Bytes()), nil
}

// Evaluate constructs ExecuteOptions for using the maven-help-plugin's 'evaluate' goal to
// evaluate a given expression from a pom file. This allows to retrieve the value of - for
// example - 'project.version' from a pom file exactly as Maven itself evaluates it.
func Evaluate(options *EvaluateOptions, expression string, command mavenExecRunner) (string, error) {
	expressionDefine := "-Dexpression=" + expression
	executeOptions := ExecuteOptions{
		PomPath:             options.PomPath,
		M2Path:              options.M2Path,
		ProjectSettingsFile: options.ProjectSettingsFile,
		GlobalSettingsFile:  options.GlobalSettingsFile,
		Goals:               []string{"org.apache.maven.plugins:maven-help-plugin:3.1.0:evaluate"},
		Defines:             []string{expressionDefine, "-DforceStdout", "-q"},
		ReturnStdout:        true,
	}
	value, err := Execute(&executeOptions, command)
	if err != nil {
		return "", err
	}
	if strings.HasPrefix(value, "null object or invalid expression") {
		return "", fmt.Errorf("expression '%s' in file '%s' could not be resolved", expression, options.PomPath)
	}
	return value, nil
}

func evaluateStdOut(options *ExecuteOptions) (*bytes.Buffer, io.Writer) {
	var stdOutBuf *bytes.Buffer
	stdOut := log.Writer()
	if options.ReturnStdout {
		stdOutBuf = new(bytes.Buffer)
		stdOut = io.MultiWriter(stdOut, stdOutBuf)
	}
	return stdOutBuf, stdOut
}

func getParametersFromOptions(options *ExecuteOptions, utils mavenUtils) ([]string, error) {
	var parameters []string

	if options.GlobalSettingsFile != "" {
		globalSettingsFileName, err := downloadSettingsIfURL(options.GlobalSettingsFile, ".pipeline/mavenGlobalSettings.xml", utils)
		if err != nil {
			return nil, err
		}
		parameters = append(parameters, "--global-settings", globalSettingsFileName)
	}

	if options.ProjectSettingsFile != "" {
		projectSettingsFileName, err := downloadSettingsIfURL(options.ProjectSettingsFile, ".pipeline/mavenProjectSettings.xml", utils)
		if err != nil {
			return nil, err
		}
		parameters = append(parameters, "--settings", projectSettingsFileName)
	}

	if options.M2Path != "" {
		parameters = append(parameters, "-Dmaven.repo.local="+options.M2Path)
	}

	if options.PomPath != "" {
		parameters = append(parameters, "--file", options.PomPath)
	}

	if options.Flags != nil {
		parameters = append(parameters, options.Flags...)
	}

	if options.Defines != nil {
		parameters = append(parameters, options.Defines...)
	}

	if !options.LogSuccessfulMavenTransfers {
		parameters = append(parameters, "-Dorg.slf4j.simpleLogger.log.org.apache.maven.cli.transfer.Slf4jMavenTransferListener=warn")
	}

	parameters = append(parameters, "--batch-mode")

	parameters = append(parameters, options.Goals...)

	return parameters, nil
}

func downloadSettingsIfURL(settingsFileOption, settingsFile string, utils mavenUtils) (string, error) {
	result := settingsFileOption
	if strings.HasPrefix(settingsFileOption, "http:") || strings.HasPrefix(settingsFileOption, "https:") {
		err := downloadSettingsFromURL(settingsFileOption, settingsFile, utils)
		if err != nil {
			return "", err
		}
		result = settingsFile
	}
	return result, nil
}

// ToDo replace with pkg/maven/settings GetSettingsFile
func downloadSettingsFromURL(url, filename string, utils mavenUtils) error {
	exists, _ := utils.FileExists(filename)
	if exists {
		log.Entry().Infof("Not downloading maven settings file, because it already exists at '%s'", filename)
		return nil
	}
	err := utils.DownloadFile(url, filename, nil, nil)
	if err != nil {
		return fmt.Errorf("failed to download maven settings from URL '%s' to file '%s': %w",
			url, filename, err)
	}
	return nil
}

func GetTestModulesExcludes() []string {
	return getTestModulesExcludes(newUtils())
}

func getTestModulesExcludes(utils mavenUtils) []string {
	var excludes []string
	exists, _ := utils.FileExists("unit-tests/pom.xml")
	if exists {
		excludes = append(excludes, "-pl", "!unit-tests")
	}
	exists, _ = utils.FileExists("integration-tests/pom.xml")
	if exists {
		excludes = append(excludes, "-pl", "!integration-tests")
	}
	return excludes
}