package runner

import (
	"bufio"
	"os"
	"path/filepath"
	"strings"
	"time"

	"github.com/logrusorgru/aurora"
	"github.com/pkg/errors"
	"go.uber.org/ratelimit"
	"gopkg.in/yaml.v2"

	"github.com/projectdiscovery/gologger"
	"github.com/projectdiscovery/nuclei/v2/internal/colorizer"
	"github.com/projectdiscovery/nuclei/v2/pkg/catalog"
	"github.com/projectdiscovery/nuclei/v2/pkg/catalog/config"
	"github.com/projectdiscovery/nuclei/v2/pkg/catalog/loader"
	"github.com/projectdiscovery/nuclei/v2/pkg/core"
	"github.com/projectdiscovery/nuclei/v2/pkg/core/inputs/hybrid"
	"github.com/projectdiscovery/nuclei/v2/pkg/model/types/severity"
	"github.com/projectdiscovery/nuclei/v2/pkg/output"
	"github.com/projectdiscovery/nuclei/v2/pkg/parsers"
	"github.com/projectdiscovery/nuclei/v2/pkg/progress"
	"github.com/projectdiscovery/nuclei/v2/pkg/projectfile"
	"github.com/projectdiscovery/nuclei/v2/pkg/protocols"
	"github.com/projectdiscovery/nuclei/v2/pkg/protocols/common/hosterrorscache"
	"github.com/projectdiscovery/nuclei/v2/pkg/protocols/common/interactsh"
	"github.com/projectdiscovery/nuclei/v2/pkg/protocols/common/protocolinit"
	"github.com/projectdiscovery/nuclei/v2/pkg/protocols/headless/engine"
	"github.com/projectdiscovery/nuclei/v2/pkg/reporting"
	"github.com/projectdiscovery/nuclei/v2/pkg/reporting/exporters/markdown"
	"github.com/projectdiscovery/nuclei/v2/pkg/reporting/exporters/sarif"
	"github.com/projectdiscovery/nuclei/v2/pkg/types"
	"github.com/projectdiscovery/nuclei/v2/pkg/utils"
	"github.com/projectdiscovery/nuclei/v2/pkg/utils/stats"
)

// Runner is a client for running the enumeration process.
type Runner struct {
	output            output.Writer
	interactsh        *interactsh.Client
	templatesConfig   *config.Config
	options           *types.Options
	projectFile       *projectfile.ProjectFile
	catalog           *catalog.Catalog
	progress          progress.Progress
	colorizer         aurora.Aurora
	issuesClient      *reporting.Client
	addColor          func(severity.Severity) string
	hmapInputProvider *hybrid.Input
	browser           *engine.Browser
	ratelimiter       ratelimit.Limiter
	hostErrors        *hosterrorscache.Cache
}

// New creates a new client for running enumeration process.
func New(options *types.Options) (*Runner, error) {
	runner := &Runner{
		options: options,
	}
	if options.UpdateNuclei {
		if err := updateNucleiVersionToLatest(runner.options.Verbose); err != nil {
			return nil, err
		}
		return nil, nil
	}
	if options.Validate {
		parsers.ShouldValidate = true
	}
	if err := runner.updateTemplates(); err != nil {
		gologger.Warning().Msgf("Could not update templates: %s\n", err)
	}
	if options.Headless {
		browser, err := engine.New(options)
		if err != nil {
			return nil, err
		}
		runner.browser = browser
	}

	runner.catalog = catalog.New(runner.options.TemplatesDirectory)

	reportingOptions, err := createReportingOptions(options)
	if err != nil {
		return nil, err
	}
	if reportingOptions != nil {
		client, err := reporting.New(reportingOptions, options.ReportingDB)
		if err != nil {
			return nil, errors.Wrap(err, "could not create issue reporting client")
		}
		runner.issuesClient = client
	}

	// output coloring
	useColor := !options.NoColor
	runner.colorizer = aurora.NewAurora(useColor)
	runner.addColor = colorizer.New(runner.colorizer)

	if options.TemplateList {
		runner.listAvailableTemplates()
		os.Exit(0)
	}

	if (len(options.Templates) == 0 || !options.NewTemplates || (options.TargetsFilePath == "" && !options.Stdin && len(options.Targets) == 0)) && options.UpdateTemplates {
		os.Exit(0)
	}

	// Initialize the input source
	hmapInput, err := hybrid.New(options)
	if err != nil {
		return nil, errors.Wrap(err, "could not create input provider")
	}
	runner.hmapInputProvider = hmapInput

	// Create the output file if asked
	outputWriter, err := output.NewStandardWriter(!options.NoColor, options.NoMeta, options.NoTimestamp, options.JSON, options.JSONRequests, options.Output, options.TraceLogFile)
	if err != nil {
		return nil, errors.Wrap(err, "could not create output file")
	}
	runner.output = outputWriter

	if options.JSON && options.EnableProgressBar {
		options.StatsJSON = true
	}
	if options.StatsJSON {
		options.EnableProgressBar = true
	}
	// Creates the progress tracking object
	var progressErr error
	runner.progress, progressErr = progress.NewStatsTicker(options.StatsInterval, options.EnableProgressBar, options.StatsJSON, options.Metrics, options.MetricsPort)
	if progressErr != nil {
		return nil, progressErr
	}

	// create project file if requested or load the existing one
	if options.Project {
		var projectFileErr error
		runner.projectFile, projectFileErr = projectfile.New(&projectfile.Options{Path: options.ProjectPath, Cleanup: utils.IsBlank(options.ProjectPath)})
		if projectFileErr != nil {
			return nil, projectFileErr
		}
	}

	if !options.NoInteractsh {
		interactshClient, err := interactsh.New(&interactsh.Options{
			ServerURL:      options.InteractshURL,
			Authorization:  options.InteractshToken,
			CacheSize:      int64(options.InteractionsCacheSize),
			Eviction:       time.Duration(options.InteractionsEviction) * time.Second,
			ColldownPeriod: time.Duration(options.InteractionsColldownPeriod) * time.Second,
			PollDuration:   time.Duration(options.InteractionsPollDuration) * time.Second,
			Output:         runner.output,
			IssuesClient:   runner.issuesClient,
			Progress:       runner.progress,
			Debug:          runner.options.Debug,
		})
		if err != nil {
			gologger.Error().Msgf("Could not create interactsh client: %s", err)
		} else {
			runner.interactsh = interactshClient
		}
	}

	if options.RateLimitMinute > 0 {
		runner.ratelimiter = ratelimit.New(options.RateLimitMinute, ratelimit.Per(60*time.Second))
	} else if options.RateLimit > 0 {
		runner.ratelimiter = ratelimit.New(options.RateLimit)
	} else {
		runner.ratelimiter = ratelimit.NewUnlimited()
	}
	return runner, nil
}

func createReportingOptions(options *types.Options) (*reporting.Options, error) {
	var reportingOptions *reporting.Options
	if options.ReportingConfig != "" {
		file, err := os.Open(options.ReportingConfig)
		if err != nil {
			return nil, errors.Wrap(err, "could not open reporting config file")
		}

		reportingOptions = &reporting.Options{}
		if parseErr := yaml.NewDecoder(file).Decode(reportingOptions); parseErr != nil {
			file.Close()
			return nil, errors.Wrap(parseErr, "could not parse reporting config file")
		}
		file.Close()
	}
	if options.MarkdownExportDirectory != "" {
		if reportingOptions != nil {
			reportingOptions.MarkdownExporter = &markdown.Options{Directory: options.MarkdownExportDirectory}
		} else {
			reportingOptions = &reporting.Options{}
			reportingOptions.MarkdownExporter = &markdown.Options{Directory: options.MarkdownExportDirectory}
		}
	}
	if options.SarifExport != "" {
		if reportingOptions != nil {
			reportingOptions.SarifExporter = &sarif.Options{File: options.SarifExport}
		} else {
			reportingOptions = &reporting.Options{}
			reportingOptions.SarifExporter = &sarif.Options{File: options.SarifExport}
		}
	}
	return reportingOptions, nil
}

// Close releases all the resources and cleans up
func (r *Runner) Close() {
	if r.output != nil {
		r.output.Close()
	}
	if r.projectFile != nil {
		r.projectFile.Close()
	}
	r.hmapInputProvider.Close()
	protocolinit.Close()
}

// RunEnumeration sets up the input layer for giving input nuclei.
// binary and runs the actual enumeration
func (r *Runner) RunEnumeration() error {
	defer r.Close()

	// If user asked for new templates to be executed, collect the list from the templates' directory.
	if r.options.NewTemplates {
		templatesLoaded, err := r.readNewTemplatesFile()
		if err != nil {
			return errors.Wrap(err, "could not get newly added templates")
		}
		r.options.Templates = append(r.options.Templates, templatesLoaded...)
	}
	ignoreFile := config.ReadIgnoreFile()
	r.options.ExcludeTags = append(r.options.ExcludeTags, ignoreFile.Tags...)
	r.options.ExcludedTemplates = append(r.options.ExcludedTemplates, ignoreFile.Files...)

	var cache *hosterrorscache.Cache
	if r.options.MaxHostError > 0 {
		cache = hosterrorscache.New(r.options.MaxHostError, hosterrorscache.DefaultMaxHostsCount).SetVerbose(r.options.Verbose)
	}
	r.hostErrors = cache

	// Create the executer options which will be used throughout the execution
	// stage by the nuclei engine modules.
	executerOpts := protocols.ExecuterOptions{
		Output:          r.output,
		Options:         r.options,
		Progress:        r.progress,
		Catalog:         r.catalog,
		IssuesClient:    r.issuesClient,
		RateLimiter:     r.ratelimiter,
		Interactsh:      r.interactsh,
		ProjectFile:     r.projectFile,
		Browser:         r.browser,
		HostErrorsCache: cache,
		Colorizer:       r.colorizer,
	}
	engine := core.New(r.options)
	engine.SetExecuterOptions(executerOpts)

	workflowLoader, err := parsers.NewLoader(&executerOpts)
	if err != nil {
		return errors.Wrap(err, "Could not create loader.")
	}
	executerOpts.WorkflowLoader = workflowLoader

	store, err := loader.New(loader.NewConfig(r.options, r.catalog, executerOpts))
	if err != nil {
		return errors.Wrap(err, "could not load templates from config")
	}
	store.Load()

	if r.options.Validate {
		if err := store.ValidateTemplates(r.options.Templates, r.options.Workflows); err != nil {
			return err
		}
		if stats.GetValue(parsers.SyntaxErrorStats) == 0 && stats.GetValue(parsers.SyntaxWarningStats) == 0 {
			gologger.Info().Msgf("All templates validated successfully\n")
		} else {
			return errors.New("encountered errors while performing template validation")
		}
		return nil // exit
	}

	r.displayExecutionInfo(store)

	var unclusteredRequests int64
	for _, template := range store.Templates() {
		// workflows will dynamically adjust the totals while running, as
		// it can't be known in advance which requests will be called
		if len(template.Workflows) > 0 {
			continue
		}
		unclusteredRequests += int64(template.TotalRequests) * r.hmapInputProvider.Count()
	}

	if r.options.VerboseVerbose {
		for _, template := range store.Templates() {
			r.logAvailableTemplate(template.Path)
		}
		for _, template := range store.Workflows() {
			r.logAvailableTemplate(template.Path)
		}
	}

	// Cluster the templates first because we want info on how many
	// templates did we cluster for showing to user in CLI
	originalTemplatesCount := len(store.Templates())
	finalTemplates, clusterCount := engine.ClusterTemplates(store.Templates())
	finalTemplates = append(finalTemplates, store.Workflows()...)

	var totalRequests int64
	for _, t := range finalTemplates {
		if len(t.Workflows) > 0 {
			continue
		}
		totalRequests += int64(t.TotalRequests) * r.hmapInputProvider.Count()
	}
	if totalRequests < unclusteredRequests {
		gologger.Info().Msgf("Templates clustered: %d (Reduced %d HTTP Requests)", clusterCount, unclusteredRequests-totalRequests)
	}
	workflowCount := len(store.Workflows())
	templateCount := originalTemplatesCount + workflowCount

	// 0 matches means no templates were found in directory
	if templateCount == 0 {
		return errors.New("no valid templates were found")
	}

	// tracks global progress and captures stdout/stderr until p.Wait finishes
	r.progress.Init(r.hmapInputProvider.Count(), templateCount, totalRequests)

	results := engine.ExecuteWithOpts(finalTemplates, r.hmapInputProvider, true)

	if r.interactsh != nil {
		matched := r.interactsh.Close()
		if matched {
			results.CAS(false, true)
		}
	}
	r.progress.Stop()

	if r.issuesClient != nil {
		r.issuesClient.Close()
	}
	if !results.Load() {
		gologger.Info().Msgf("No results found. Better luck next time!")
	}
	if r.browser != nil {
		r.browser.Close()
	}
	return nil
}

// displayExecutionInfo displays misc info about the nuclei engine execution
func (r *Runner) displayExecutionInfo(store *loader.Store) {
	// Display stats for any loaded templates' syntax warnings or errors
	stats.Display(parsers.SyntaxWarningStats)
	stats.Display(parsers.SyntaxErrorStats)

	builder := &strings.Builder{}
	if r.templatesConfig != nil && r.templatesConfig.NucleiLatestVersion != "" {
		builder.WriteString(" (")

		if strings.Contains(config.Version, "-dev") {
			builder.WriteString(r.colorizer.Blue("development").String())
		} else if config.Version == r.templatesConfig.NucleiLatestVersion {
			builder.WriteString(r.colorizer.Green("latest").String())
		} else {
			builder.WriteString(r.colorizer.Red("outdated").String())
		}
		builder.WriteString(")")
	}
	messageStr := builder.String()
	builder.Reset()

	gologger.Info().Msgf("Using Nuclei Engine %s%s", config.Version, messageStr)

	if r.templatesConfig != nil && r.templatesConfig.NucleiTemplatesLatestVersion != "" { // TODO extract duplicated logic
		builder.WriteString(" (")

		if r.templatesConfig.TemplateVersion == r.templatesConfig.NucleiTemplatesLatestVersion {
			builder.WriteString(r.colorizer.Green("latest").String())
		} else {
			builder.WriteString(r.colorizer.Red("outdated").String())
		}
		builder.WriteString(")")
	}
	messageStr = builder.String()
	builder.Reset()

	if r.templatesConfig != nil {
		gologger.Info().Msgf("Using Nuclei Templates %s%s", r.templatesConfig.TemplateVersion, messageStr)
	}
	if r.interactsh != nil {
		gologger.Info().Msgf("Using Interactsh Server %s", r.options.InteractshURL)
	}
	if len(store.Templates()) > 0 {
		gologger.Info().Msgf("Templates added in last update: %d", r.countNewTemplates())
		gologger.Info().Msgf("Templates loaded for scan: %d", len(store.Templates()))
	}
	if len(store.Workflows()) > 0 {
		gologger.Info().Msgf("Workflows loaded for scan: %d", len(store.Workflows()))
	}
}

// readNewTemplatesFile reads newly added templates from directory if it exists
func (r *Runner) readNewTemplatesFile() ([]string, error) {
	if r.templatesConfig == nil {
		return nil, nil
	}
	additionsFile := filepath.Join(r.templatesConfig.TemplatesDirectory, ".new-additions")
	file, err := os.Open(additionsFile)
	if err != nil {
		return nil, err
	}
	defer file.Close()

	templatesList := []string{}
	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		text := scanner.Text()
		if text == "" {
			continue
		}
		templatesList = append(templatesList, text)
	}
	return templatesList, nil
}

// countNewTemplates returns the number of newly added templates
func (r *Runner) countNewTemplates() int {
	if r.templatesConfig == nil {
		return 0
	}
	additionsFile := filepath.Join(r.templatesConfig.TemplatesDirectory, ".new-additions")
	file, err := os.Open(additionsFile)
	if err != nil {
		return 0
	}
	defer file.Close()

	count := 0
	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		text := scanner.Text()
		if text == "" {
			continue
		}
		count++
	}
	return count
}