package cmd

import (
	"fmt"
	"os"
	"path/filepath"
	"sort"
	"strconv"
	"strings"
	"time"

	"github.com/SAP/jenkins-library/pkg/npm"

	"github.com/360EntSecGroup-Skylar/excelize/v2"
	"github.com/SAP/jenkins-library/pkg/command"
	piperhttp "github.com/SAP/jenkins-library/pkg/http"
	"github.com/SAP/jenkins-library/pkg/log"
	"github.com/SAP/jenkins-library/pkg/piperutils"
	"github.com/SAP/jenkins-library/pkg/telemetry"
	"github.com/SAP/jenkins-library/pkg/versioning"
	ws "github.com/SAP/jenkins-library/pkg/whitesource"
)

// just to make the lines less long
type ScanOptions = whitesourceExecuteScanOptions

// whitesource defines the functions that are expected by the step implementation to
// be available from the whitesource system.
type whitesource interface {
	GetProductByName(productName string) (ws.Product, error)
	CreateProduct(productName string) (string, error)
	SetProductAssignments(productToken string, membership, admins, alertReceivers *ws.Assignment) error
	GetProjectsMetaInfo(productToken string) ([]ws.Project, error)
	GetProjectToken(productToken, projectName string) (string, error)
	GetProjectByToken(projectToken string) (ws.Project, error)
	GetProjectRiskReport(projectToken string) ([]byte, error)
	GetProjectVulnerabilityReport(projectToken string, format string) ([]byte, error)
	GetProjectAlerts(projectToken string) ([]ws.Alert, error)
	GetProjectLibraryLocations(projectToken string) ([]ws.Library, error)
}

type whitesourceUtils interface {
	ws.Utils

	GetArtifactCoordinates(buildTool, buildDescriptorFile string,
		options *versioning.Options) (versioning.Coordinates, error)

	Now() time.Time
}

type whitesourceUtilsBundle struct {
	*piperhttp.Client
	*command.Command
	*piperutils.Files
	npmExecutor npm.Executor
}

func (w *whitesourceUtilsBundle) FileOpen(name string, flag int, perm os.FileMode) (ws.File, error) {
	return os.OpenFile(name, flag, perm)
}

func (w *whitesourceUtilsBundle) GetArtifactCoordinates(buildTool, buildDescriptorFile string,
	options *versioning.Options) (versioning.Coordinates, error) {
	artifact, err := versioning.GetArtifact(buildTool, buildDescriptorFile, options, w)
	if err != nil {
		return nil, err
	}
	return artifact.GetCoordinates()
}

func (w *whitesourceUtilsBundle) getNpmExecutor(config *ws.ScanOptions) npm.Executor {
	if w.npmExecutor == nil {
		w.npmExecutor = npm.NewExecutor(npm.ExecutorOptions{DefaultNpmRegistry: config.DefaultNpmRegistry})
	}
	return w.npmExecutor
}

func (w *whitesourceUtilsBundle) FindPackageJSONFiles(config *ws.ScanOptions) ([]string, error) {
	return w.getNpmExecutor(config).FindPackageJSONFilesWithExcludes(config.BuildDescriptorExcludeList)
}

func (w *whitesourceUtilsBundle) InstallAllNPMDependencies(config *ws.ScanOptions, packageJSONFiles []string) error {
	return w.getNpmExecutor(config).InstallAllDependencies(packageJSONFiles)
}

func (w *whitesourceUtilsBundle) Now() time.Time {
	return time.Now()
}

func newWhitesourceUtils(config *ScanOptions) *whitesourceUtilsBundle {
	utils := whitesourceUtilsBundle{
		Client:  &piperhttp.Client{},
		Command: &command.Command{},
		Files:   &piperutils.Files{},
	}
	// Reroute cmd output to logging framework
	utils.Stdout(log.Writer())
	utils.Stderr(log.Writer())
	// Configure HTTP Client
	utils.SetOptions(piperhttp.ClientOptions{TransportTimeout: time.Duration(config.Timeout) * time.Second})
	return &utils
}

func newWhitesourceScan(config *ScanOptions) *ws.Scan {
	return &ws.Scan{
		AggregateProjectName: config.ProjectName,
		ProductVersion:       config.ProductVersion,
	}
}

func whitesourceExecuteScan(config ScanOptions, _ *telemetry.CustomData, commonPipelineEnvironment *whitesourceExecuteScanCommonPipelineEnvironment) {
	utils := newWhitesourceUtils(&config)
	scan := newWhitesourceScan(&config)
	sys := ws.NewSystem(config.ServiceURL, config.OrgToken, config.UserToken, time.Duration(config.Timeout)*time.Second)
	err := runWhitesourceExecuteScan(&config, scan, utils, sys, commonPipelineEnvironment)
	if err != nil {
		log.Entry().WithError(err).Fatal("step execution failed")
	}
}

func runWhitesourceExecuteScan(config *ScanOptions, scan *ws.Scan, utils whitesourceUtils, sys whitesource, commonPipelineEnvironment *whitesourceExecuteScanCommonPipelineEnvironment) error {
	if err := resolveAggregateProjectName(config, scan, sys); err != nil {
		return err
	}

	if err := resolveProjectIdentifiers(config, scan, utils, sys); err != nil {
		return fmt.Errorf("failed to resolve project identifiers: %w", err)
	}

	if config.AggregateVersionWideReport {
		// Generate a vulnerability report for all projects with version = config.ProjectVersion
		// Note that this is not guaranteed that all projects are from the same scan.
		// For example, if a module was removed from the source code, the project may still
		// exist in the WhiteSource system.
		if err := aggregateVersionWideLibraries(config, utils, sys); err != nil {
			return fmt.Errorf("failed to aggregate version wide libraries: %w", err)
		}
		if err := aggregateVersionWideVulnerabilities(config, utils, sys); err != nil {
			return fmt.Errorf("failed to aggregate version wide vulnerabilities: %w", err)
		}
	} else {
		if err := runWhitesourceScan(config, scan, utils, sys, commonPipelineEnvironment); err != nil {
			return fmt.Errorf("failed to execute WhiteSource scan: %w", err)
		}
	}
	return nil
}

func runWhitesourceScan(config *ScanOptions, scan *ws.Scan, utils whitesourceUtils, sys whitesource, commonPipelineEnvironment *whitesourceExecuteScanCommonPipelineEnvironment) error {
	// Start the scan
	if err := executeScan(config, scan, utils); err != nil {
		return err
	}

	// Could perhaps use scan.updateProjects(sys) directly... have not investigated what could break
	if err := resolveProjectIdentifiers(config, scan, utils, sys); err != nil {
		return err
	}

	log.Entry().Info("-----------------------------------------------------")
	log.Entry().Infof("Product Version: '%s'", config.ProductVersion)
	log.Entry().Info("Scanned projects:")
	for _, project := range scan.ScannedProjects() {
		log.Entry().Infof("  Name: '%s', token: %s", project.Name, project.Token)
	}
	log.Entry().Info("-----------------------------------------------------")

	if err := checkAndReportScanResults(config, scan, utils, sys); err != nil {
		return err
	}

	persistScannedProjects(config, scan, commonPipelineEnvironment)

	return nil
}

func checkAndReportScanResults(config *ScanOptions, scan *ws.Scan, utils whitesourceUtils, sys whitesource) error {
	if !config.Reporting && !config.SecurityVulnerabilities {
		return nil
	}
	// Wait for WhiteSource backend to propagate the changes before downloading any reports.
	if err := scan.BlockUntilReportsAreReady(sys); err != nil {
		return err
	}
	if config.Reporting {
		paths, err := scan.DownloadReports(ws.ReportOptions{
			ReportDirectory:           config.ReportDirectoryName,
			VulnerabilityReportFormat: config.VulnerabilityReportFormat,
		}, utils, sys)
		if err != nil {
			return err
		}
		piperutils.PersistReportsAndLinks("whitesourceExecuteScan", "", nil, paths)
	}
	if config.SecurityVulnerabilities {
		if err := checkSecurityViolations(config, scan, sys); err != nil {
			return err
		}
	}
	return nil
}

func createWhiteSourceProduct(config *ScanOptions, sys whitesource) (string, error) {
	log.Entry().Infof("Attempting to create new WhiteSource product for '%s'..", config.ProductName)
	productToken, err := sys.CreateProduct(config.ProductName)
	if err != nil {
		return "", fmt.Errorf("failed to create WhiteSource product: %w", err)
	}

	var admins ws.Assignment
	for _, address := range config.EmailAddressesOfInitialProductAdmins {
		admins.UserAssignments = append(admins.UserAssignments, ws.UserAssignment{Email: address})
	}

	err = sys.SetProductAssignments(productToken, nil, &admins, nil)
	if err != nil {
		return "", fmt.Errorf("failed to set admins on new WhiteSource product: %w", err)
	}

	return productToken, nil
}

func resolveProjectIdentifiers(config *ScanOptions, scan *ws.Scan, utils whitesourceUtils, sys whitesource) error {
	if scan.AggregateProjectName == "" || config.ProductVersion == "" {
		options := &versioning.Options{
			ProjectSettingsFile: config.ProjectSettingsFile,
			GlobalSettingsFile:  config.GlobalSettingsFile,
			M2Path:              config.M2Path,
		}
		coordinates, err := utils.GetArtifactCoordinates(config.BuildTool, config.BuildDescriptorFile, options)
		if err != nil {
			return fmt.Errorf("failed to get build artifact description: %w", err)
		}

		nameTmpl := `{{list .GroupID .ArtifactID | join "-" | trimAll "-"}}`
		name, version := versioning.DetermineProjectCoordinates(nameTmpl, config.VersioningModel, coordinates)
		if scan.AggregateProjectName == "" {
			log.Entry().Infof("Resolved project name '%s' from descriptor file", name)
			scan.AggregateProjectName = name
		}
		if config.ProductVersion == "" {
			log.Entry().Infof("Resolved product version '%s' from descriptor file with versioning '%s'",
				version, config.VersioningModel)
			config.ProductVersion = version
		}
	}
	scan.ProductVersion = validateProductVersion(config.ProductVersion)

	if err := resolveProductToken(config, sys); err != nil {
		return err
	}
	if err := resolveAggregateProjectToken(config, sys); err != nil {
		return err
	}

	return scan.UpdateProjects(config.ProductToken, sys)
}

// resolveProductToken resolves the token of the WhiteSource Product specified by config.ProductName,
// unless the user provided a token in config.ProductToken already, or it was previously resolved.
// If no Product can be found for the given config.ProductName, and the parameter
// config.CreatePipelineFromProduct is set, an attempt will be made to create the product and
// configure the initial product admins.
func resolveProductToken(config *ScanOptions, sys whitesource) error {
	if config.ProductToken != "" {
		return nil
	}
	log.Entry().Infof("Attempting to resolve product token for product '%s'..", config.ProductName)
	product, err := sys.GetProductByName(config.ProductName)
	if err != nil && config.CreateProductFromPipeline {
		product = ws.Product{}
		product.Token, err = createWhiteSourceProduct(config, sys)
		if err != nil {
			return err
		}
	}
	if err != nil {
		return err
	}
	log.Entry().Infof("Resolved product token: '%s'..", product.Token)
	config.ProductToken = product.Token
	return nil
}

// resolveAggregateProjectName checks if config.ProjectToken is configured, and if so, expects a WhiteSource
// project with that token to exist. The AggregateProjectName in the ws.Scan is then configured with that
// project's name.
func resolveAggregateProjectName(config *ScanOptions, scan *ws.Scan, sys whitesource) error {
	if config.ProjectToken == "" {
		return nil
	}
	log.Entry().Infof("Attempting to resolve aggregate project name for token '%s'..", config.ProjectToken)
	// If the user configured the "projectToken" parameter, we expect this project to exist in the backend.
	project, err := sys.GetProjectByToken(config.ProjectToken)
	if err != nil {
		return err
	}
	nameVersion := strings.Split(project.Name, " - ")
	scan.AggregateProjectName = nameVersion[0]
	log.Entry().Infof("Resolve aggregate project name '%s'..", scan.AggregateProjectName)
	return nil
}

// resolveAggregateProjectToken fetches the token of the WhiteSource Project specified by config.ProjectName
// and stores it in config.ProjectToken.
// The user can configure a projectName or projectToken of the project to be used as for aggregation of scan results.
func resolveAggregateProjectToken(config *ScanOptions, sys whitesource) error {
	if config.ProjectToken != "" || config.ProjectName == "" {
		return nil
	}
	log.Entry().Infof("Attempting to resolve project token for project '%s'..", config.ProjectName)
	fullProjName := fmt.Sprintf("%s - %s", config.ProjectName, config.ProductVersion)
	projectToken, err := sys.GetProjectToken(config.ProductToken, fullProjName)
	if err != nil {
		return err
	}
	// A project may not yet exist for this project name-version combo.
	// It will be created by the scan, we retrieve the token again after scanning.
	if projectToken != "" {
		log.Entry().Infof("Resolved project token: '%s'..", projectToken)
		config.ProjectToken = projectToken
	} else {
		log.Entry().Infof("Project '%s' not yet present in WhiteSource", fullProjName)
	}
	return nil
}

// validateProductVersion makes sure that the version does not contain a dash "-".
func validateProductVersion(version string) string {
	// TrimLeft() removes all "-" from the beginning, unlike TrimPrefix()!
	version = strings.TrimLeft(version, "-")
	if strings.Contains(version, "-") {
		version = strings.SplitN(version, "-", 1)[0]
	}
	return version
}

func wsScanOptions(config *ScanOptions) *ws.ScanOptions {
	return &ws.ScanOptions{
		ScanType:                   config.ScanType,
		OrgToken:                   config.OrgToken,
		UserToken:                  config.UserToken,
		ProductName:                config.ProductName,
		ProductToken:               config.ProductToken,
		ProjectName:                config.ProjectName,
		BuildDescriptorExcludeList: config.BuildDescriptorExcludeList,
		PomPath:                    config.BuildDescriptorFile,
		M2Path:                     config.M2Path,
		GlobalSettingsFile:         config.GlobalSettingsFile,
		ProjectSettingsFile:        config.ProjectSettingsFile,
		InstallArtifacts:           config.InstallArtifacts,
		DefaultNpmRegistry:         config.DefaultNpmRegistry,
		AgentDownloadURL:           config.AgentDownloadURL,
		AgentFileName:              config.AgentFileName,
		ConfigFilePath:             config.ConfigFilePath,
		Includes:                   config.Includes,
		Excludes:                   config.Excludes,
	}
}

// executeScan executes different types of scans depending on the scanType parameter.
// The default is to download the Unified Agent and use it to perform the scan.
func executeScan(config *ScanOptions, scan *ws.Scan, utils whitesourceUtils) error {
	if config.ScanType == "" {
		config.ScanType = config.BuildTool
	}

	options := wsScanOptions(config)

	switch config.ScanType {
	case "mta":
		// Execute scan for maven and all npm modules
		if err := scan.ExecuteMTAScan(options, utils); err != nil {
			return err
		}
	case "maven":
		// Execute scan with maven plugin goal
		if err := scan.ExecuteMavenScan(options, utils); err != nil {
			return err
		}
	case "npm":
		// Execute scan with in each npm module using npm.Executor
		if err := scan.ExecuteNpmScan(options, utils); err != nil {
			return err
		}
	case "yarn":
		// Execute scan with whitesource yarn plugin
		if err := scan.ExecuteYarnScan(options, utils); err != nil {
			return err
		}
	default:
		// Execute scan with Unified Agent jar file
		if err := scan.ExecuteUAScan(options, utils); err != nil {
			return err
		}
	}
	return nil
}

func checkSecurityViolations(config *ScanOptions, scan *ws.Scan, sys whitesource) error {
	// Check for security vulnerabilities and fail the build if cvssSeverityLimit threshold is crossed
	// convert config.CvssSeverityLimit to float64
	cvssSeverityLimit, err := strconv.ParseFloat(config.CvssSeverityLimit, 64)
	if err != nil {
		log.SetErrorCategory(log.ErrorConfiguration)
		return fmt.Errorf("failed to parse parameter cvssSeverityLimit (%s) "+
			"as floating point number: %w", config.CvssSeverityLimit, err)
	}
	if config.ProjectToken != "" {
		project := ws.Project{Name: config.ProjectName, Token: config.ProjectToken}
		if err := checkProjectSecurityViolations(cvssSeverityLimit, project, sys); err != nil {
			return err
		}
	} else {
		for _, project := range scan.ScannedProjects() {
			if err := checkProjectSecurityViolations(cvssSeverityLimit, project, sys); err != nil {
				return err
			}
		}
	}
	return nil
}

// checkSecurityViolations checks security violations and returns an error if the configured severity limit is crossed.
func checkProjectSecurityViolations(cvssSeverityLimit float64, project ws.Project, sys whitesource) error {
	// get project alerts (vulnerabilities)
	alerts, err := sys.GetProjectAlerts(project.Token)
	if err != nil {
		return fmt.Errorf("failed to retrieve project alerts from Whitesource: %w", err)
	}

	severeVulnerabilities := 0
	// https://github.com/SAP/jenkins-library/blob/master/vars/whitesourceExecuteScan.groovy#L537
	for _, alert := range alerts {
		vuln := alert.Vulnerability
		if (vuln.Score >= cvssSeverityLimit || vuln.CVSS3Score >= cvssSeverityLimit) && cvssSeverityLimit >= 0 {
			log.Entry().Infof("Vulnerability with Score %v / CVSS3Score %v treated as severe",
				vuln.Score, vuln.CVSS3Score)
			severeVulnerabilities++
		} else {
			log.Entry().Infof("Ignoring vulnerability with Score %v / CVSS3Score %v",
				vuln.Score, vuln.CVSS3Score)
		}
	}

	//https://github.com/SAP/jenkins-library/blob/master/vars/whitesourceExecuteScan.groovy#L547
	nonSevereVulnerabilities := len(alerts) - severeVulnerabilities
	if nonSevereVulnerabilities > 0 {
		log.Entry().Warnf("WARNING: %v Open Source Software Security vulnerabilities with "+
			"CVSS score below threshold %.1f detected in project %s.", nonSevereVulnerabilities,
			cvssSeverityLimit, project.Name)
	} else if len(alerts) == 0 {
		log.Entry().Infof("No Open Source Software Security vulnerabilities detected in project %s",
			project.Name)
	}

	// https://github.com/SAP/jenkins-library/blob/master/vars/whitesourceExecuteScan.groovy#L558
	if severeVulnerabilities > 0 {
		return fmt.Errorf("%v Open Source Software Security vulnerabilities with CVSS score greater "+
			"or equal to %.1f detected in project %s",
			severeVulnerabilities, cvssSeverityLimit, project.Name)
	}
	return nil
}

func aggregateVersionWideLibraries(config *ScanOptions, utils whitesourceUtils, sys whitesource) error {
	log.Entry().Infof("Aggregating list of libraries used for all projects with version: %s", config.ProductVersion)

	projects, err := sys.GetProjectsMetaInfo(config.ProductToken)
	if err != nil {
		return err
	}

	versionWideLibraries := map[string][]ws.Library{} // maps project name to slice of libraries
	for _, project := range projects {
		projectVersion := strings.Split(project.Name, " - ")[1]
		projectName := strings.Split(project.Name, " - ")[0]
		if projectVersion == config.ProductVersion {
			libs, err := sys.GetProjectLibraryLocations(project.Token)
			if err != nil {
				return err
			}
			log.Entry().Infof("Found project: %s with %v libraries.", project.Name, len(libs))
			versionWideLibraries[projectName] = libs
		}
	}
	if err := newLibraryCSVReport(versionWideLibraries, config, utils); err != nil {
		return err
	}
	return nil
}

func aggregateVersionWideVulnerabilities(config *ScanOptions, utils whitesourceUtils, sys whitesource) error {
	log.Entry().Infof("Aggregating list of vulnerabilities for all projects with version: %s", config.ProductVersion)

	projects, err := sys.GetProjectsMetaInfo(config.ProductToken)
	if err != nil {
		return err
	}

	var versionWideAlerts []ws.Alert // all alerts for a given project version
	projectNames := ``               // holds all project tokens considered a part of the report for debugging
	for _, project := range projects {
		projectVersion := strings.Split(project.Name, " - ")[1]
		if projectVersion == config.ProductVersion {
			projectNames += project.Name + "\n"
			alerts, err := sys.GetProjectAlerts(project.Token)
			if err != nil {
				return err
			}
			log.Entry().Infof("Found project: %s with %v vulnerabilities.", project.Name, len(alerts))
			versionWideAlerts = append(versionWideAlerts, alerts...)
		}
	}

	reportPath := filepath.Join(config.ReportDirectoryName, "project-names-aggregated.txt")
	if err := utils.FileWrite(reportPath, []byte(projectNames), 0644); err != nil {
		return err
	}
	if err := newVulnerabilityExcelReport(versionWideAlerts, config, utils); err != nil {
		return err
	}
	return nil
}

const wsReportTimeStampLayout = "20060102-150405"

// outputs an slice of alerts to an excel file
func newVulnerabilityExcelReport(alerts []ws.Alert, config *ScanOptions, utils whitesourceUtils) error {
	file := excelize.NewFile()
	streamWriter, err := file.NewStreamWriter("Sheet1")
	if err != nil {
		return err
	}
	styleID, err := file.NewStyle(`{"font":{"color":"#777777"}}`)
	if err != nil {
		return err
	}
	if err := fillVulnerabilityExcelReport(alerts, streamWriter, styleID); err != nil {
		return err
	}
	if err := streamWriter.Flush(); err != nil {
		return err
	}

	if err := utils.MkdirAll(config.ReportDirectoryName, 0777); err != nil {
		return err
	}

	fileName := filepath.Join(config.ReportDirectoryName,
		fmt.Sprintf("vulnerabilities-%s.xlsx", utils.Now().Format(wsReportTimeStampLayout)))
	stream, err := utils.FileOpen(fileName, os.O_WRONLY|os.O_TRUNC|os.O_CREATE, 0666)
	if err != nil {
		return err
	}
	if err := file.Write(stream); err != nil {
		return err
	}
	return nil
}

func fillVulnerabilityExcelReport(alerts []ws.Alert, streamWriter *excelize.StreamWriter, styleID int) error {
	rows := []struct {
		axis  string
		title string
	}{
		{"A1", "Severity"},
		{"B1", "Library"},
		{"C1", "Vulnerability ID"},
		{"D1", "Project"},
		{"E1", "Resolution"},
	}
	for _, row := range rows {
		err := streamWriter.SetRow(row.axis, []interface{}{excelize.Cell{StyleID: styleID, Value: row.title}})
		if err != nil {
			return err
		}
	}

	for i, alert := range alerts {
		row := make([]interface{}, 5)
		vuln := alert.Vulnerability
		row[0] = vuln.Severity
		row[1] = alert.Library.Filename
		row[2] = vuln.Level
		row[3] = alert.Project
		row[4] = vuln.FixResolutionText
		cell, _ := excelize.CoordinatesToCellName(1, i+2)
		if err := streamWriter.SetRow(cell, row); err != nil {
			log.Entry().Errorf("failed to write alert row: %v", err)
		}
	}
	return nil
}

// outputs an slice of libraries to an excel file based on projects with version == config.ProductVersion
func newLibraryCSVReport(libraries map[string][]ws.Library, config *ScanOptions, utils whitesourceUtils) error {
	output := "Library Name, Project Name\n"
	for projectName, libraries := range libraries {
		log.Entry().Infof("Writing %v libraries for project %s to excel report..", len(libraries), projectName)
		for _, library := range libraries {
			output += library.Name + ", " + projectName + "\n"
		}
	}

	// Ensure reporting directory exists
	if err := utils.MkdirAll(config.ReportDirectoryName, 0777); err != nil {
		return err
	}

	// Write result to file
	fileName := fmt.Sprintf("%s/libraries-%s.csv", config.ReportDirectoryName,
		utils.Now().Format(wsReportTimeStampLayout))
	if err := utils.FileWrite(fileName, []byte(output), 0777); err != nil {
		return err
	}
	return nil
}

// persistScannedProjects writes all actually scanned WhiteSource project names as comma separated
// string into the Common Pipeline Environment, from where it can be used by sub-sequent steps.
func persistScannedProjects(config *ScanOptions, scan *ws.Scan, commonPipelineEnvironment *whitesourceExecuteScanCommonPipelineEnvironment) {
	projectNames := []string{}
	if config.ProjectName != "" {
		projectNames = []string{config.ProjectName + " - " + config.ProductVersion}
	} else {
		for _, project := range scan.ScannedProjects() {
			projectNames = append(projectNames, project.Name)
		}
		// Sorting helps the list become stable across pipeline runs (and in the unit tests),
		// as the order in which we travers map keys is not deterministic.
		sort.Strings(projectNames)
	}
	commonPipelineEnvironment.custom.whitesourceProjectNames = projectNames
}