package hubtest

import (
	"bufio"
	"fmt"
	"io"
	"os"
	"sort"
	"strings"
	"time"

	"github.com/antonmedv/expr"
	"github.com/enescakir/emoji"
	"github.com/fatih/color"
	diff "github.com/r3labs/diff/v2"
	log "github.com/sirupsen/logrus"
	"gopkg.in/yaml.v2"

	"github.com/crowdsecurity/crowdsec/pkg/exprhelpers"
	"github.com/crowdsecurity/crowdsec/pkg/types"
)

type AssertFail struct {
	File       string
	Line       int
	Expression string
	Debug      map[string]string
}

type ParserAssert struct {
	File              string
	AutoGenAssert     bool
	AutoGenAssertData string
	NbAssert          int
	Fails             []AssertFail
	Success           bool
	TestData          *ParserResults
}

type ParserResult struct {
	Evt     types.Event
	Success bool
}

type ParserResults map[string]map[string][]ParserResult

func NewParserAssert(file string) *ParserAssert {
	ParserAssert := &ParserAssert{
		File:          file,
		NbAssert:      0,
		Success:       false,
		Fails:         make([]AssertFail, 0),
		AutoGenAssert: false,
		TestData:      &ParserResults{},
	}

	return ParserAssert
}

func (p *ParserAssert) AutoGenFromFile(filename string) (string, error) {
	err := p.LoadTest(filename)
	if err != nil {
		return "", err
	}

	ret := p.AutoGenParserAssert()

	return ret, nil
}

func (p *ParserAssert) LoadTest(filename string) error {
	parserDump, err := LoadParserDump(filename)
	if err != nil {
		return fmt.Errorf("loading parser dump file: %+v", err)
	}

	p.TestData = parserDump

	return nil
}

func (p *ParserAssert) AssertFile(testFile string) error {
	file, err := os.Open(p.File)

	if err != nil {
		return fmt.Errorf("failed to open")
	}

	if err := p.LoadTest(testFile); err != nil {
		return fmt.Errorf("unable to load parser dump file '%s': %s", testFile, err)
	}

	scanner := bufio.NewScanner(file)
	scanner.Split(bufio.ScanLines)

	nbLine := 0

	for scanner.Scan() {
		nbLine++

		if scanner.Text() == "" {
			continue
		}

		ok, err := p.Run(scanner.Text())
		if err != nil {
			return fmt.Errorf("unable to run assert '%s': %+v", scanner.Text(), err)
		}

		p.NbAssert++

		if !ok {
			log.Debugf("%s is FALSE", scanner.Text())
			failedAssert := &AssertFail{
				File:       p.File,
				Line:       nbLine,
				Expression: scanner.Text(),
				Debug:      make(map[string]string),
			}

			match := variableRE.FindStringSubmatch(scanner.Text())
			variable := ""

			if len(match) == 0 {
				log.Infof("Couldn't get variable of line '%s'", scanner.Text())
				variable = scanner.Text()
			} else {
				variable = match[1]
			}

			result, err := p.EvalExpression(variable)
			if err != nil {
				log.Errorf("unable to evaluate variable '%s': %s", variable, err)
				continue
			}

			failedAssert.Debug[variable] = result
			p.Fails = append(p.Fails, *failedAssert)

			continue
		}
		//fmt.Printf(" %s '%s'\n", emoji.GreenSquare, scanner.Text())
	}

	file.Close()

	if p.NbAssert == 0 {
		assertData, err := p.AutoGenFromFile(testFile)
		if err != nil {
			return fmt.Errorf("couldn't generate assertion: %s", err)
		}

		p.AutoGenAssertData = assertData
		p.AutoGenAssert = true
	}

	if len(p.Fails) == 0 {
		p.Success = true
	}

	return nil
}

func (p *ParserAssert) RunExpression(expression string) (interface{}, error) {
	//debug doesn't make much sense with the ability to evaluate "on the fly"
	//var debugFilter *exprhelpers.ExprDebugger
	var output interface{}

	env := map[string]interface{}{"results": *p.TestData}

	runtimeFilter, err := expr.Compile(expression, exprhelpers.GetExprOptions(env)...)
	if err != nil {
		log.Errorf("failed to compile '%s' : %s", expression, err)
		return output, err
	}

	//dump opcode in trace level
	log.Tracef("%s", runtimeFilter.Disassemble())

	output, err = expr.Run(runtimeFilter, env)
	if err != nil {
		log.Warningf("running : %s", expression)
		log.Warningf("runtime error : %s", err)

		return output, fmt.Errorf("while running expression %s: %w", expression, err)
	}

	return output, nil
}

func (p *ParserAssert) EvalExpression(expression string) (string, error) {
	output, err := p.RunExpression(expression)
	if err != nil {
		return "", err
	}

	ret, err := yaml.Marshal(output)

	if err != nil {
		return "", err
	}

	return string(ret), nil
}

func (p *ParserAssert) Run(assert string) (bool, error) {
	output, err := p.RunExpression(assert)
	if err != nil {
		return false, err
	}

	switch out := output.(type) {
	case bool:
		return out, nil
	default:
		return false, fmt.Errorf("assertion '%s' is not a condition", assert)
	}
}

func Escape(val string) string {
	val = strings.ReplaceAll(val, `\`, `\\`)
	val = strings.ReplaceAll(val, `"`, `\"`)

	return val
}

func (p *ParserAssert) AutoGenParserAssert() string {
	//attempt to autogen parser asserts
	ret := fmt.Sprintf("len(results) == %d\n", len(*p.TestData))

	//sort map keys for consistent order
	stages := sortedMapKeys(*p.TestData)

	for _, stage := range stages {
		parsers := (*p.TestData)[stage]

		//sort map keys for consistent order
		pnames := sortedMapKeys(parsers)

		for _, parser := range pnames {
			presults := parsers[parser]
			ret += fmt.Sprintf(`len(results["%s"]["%s"]) == %d`+"\n", stage, parser, len(presults))

			for pidx, result := range presults {
				ret += fmt.Sprintf(`results["%s"]["%s"][%d].Success == %t`+"\n", stage, parser, pidx, result.Success)

				if !result.Success {
					continue
				}

				for _, pkey := range sortedMapKeys(result.Evt.Parsed) {
					pval := result.Evt.Parsed[pkey]
					if pval == "" {
						continue
					}

					ret += fmt.Sprintf(`results["%s"]["%s"][%d].Evt.Parsed["%s"] == "%s"`+"\n", stage, parser, pidx, pkey, Escape(pval))
				}

				for _, mkey := range sortedMapKeys(result.Evt.Meta) {
					mval := result.Evt.Meta[mkey]
					if mval == "" {
						continue
					}

					ret += fmt.Sprintf(`results["%s"]["%s"][%d].Evt.Meta["%s"] == "%s"`+"\n", stage, parser, pidx, mkey, Escape(mval))
				}

				for _, ekey := range sortedMapKeys(result.Evt.Enriched) {
					eval := result.Evt.Enriched[ekey]
					if eval == "" {
						continue
					}

					ret += fmt.Sprintf(`results["%s"]["%s"][%d].Evt.Enriched["%s"] == "%s"`+"\n", stage, parser, pidx, ekey, Escape(eval))
				}

				for _, ukey := range sortedMapKeys(result.Evt.Unmarshaled) {
					uval := result.Evt.Unmarshaled[ukey]
					if uval == "" {
						continue
					}

					base := fmt.Sprintf(`results["%s"]["%s"][%d].Evt.Unmarshaled["%s"]`, stage, parser, pidx, ukey)

					for _, line := range p.buildUnmarshaledAssert(base, uval) {
						ret += line
					}
				}

				ret += fmt.Sprintf(`results["%s"]["%s"][%d].Evt.Whitelisted == %t`+"\n", stage, parser, pidx, result.Evt.Whitelisted)

				if result.Evt.WhitelistReason != "" {
					ret += fmt.Sprintf(`results["%s"]["%s"][%d].Evt.WhitelistReason == "%s"`+"\n", stage, parser, pidx, Escape(result.Evt.WhitelistReason))
				}
			}
		}
	}

	return ret
}

func (p *ParserAssert) buildUnmarshaledAssert(ekey string, eval interface{}) []string {
	ret := make([]string, 0)

	switch val := eval.(type) {
	case map[string]interface{}:
		for k, v := range val {
			ret = append(ret, p.buildUnmarshaledAssert(fmt.Sprintf(`%s["%s"]`, ekey, k), v)...)
		}
	case map[interface{}]interface{}:
		for k, v := range val {
			ret = append(ret, p.buildUnmarshaledAssert(fmt.Sprintf(`%s["%s"]`, ekey, k), v)...)
		}
	case []interface{}:
	case string:
		ret = append(ret, fmt.Sprintf(`%s == "%s"`+"\n", ekey, Escape(val)))
	case bool:
		ret = append(ret, fmt.Sprintf(`%s == %t`+"\n", ekey, val))
	case int:
		ret = append(ret, fmt.Sprintf(`%s == %d`+"\n", ekey, val))
	case float64:
		ret = append(ret, fmt.Sprintf(`FloatApproxEqual(%s, %f)`+"\n",
			ekey, val))
	default:
		log.Warningf("unknown type '%T' for key '%s'", val, ekey)
	}

	return ret
}

func LoadParserDump(filepath string) (*ParserResults, error) {
	dumpData, err := os.Open(filepath)
	if err != nil {
		return nil, err
	}
	defer dumpData.Close()

	results, err := io.ReadAll(dumpData)
	if err != nil {
		return nil, err
	}

	pdump := ParserResults{}

	if err := yaml.Unmarshal(results, &pdump); err != nil {
		return nil, err
	}

	/* we know that some variables should always be set,
	let's check if they're present in last parser output of last stage */

	stages := sortedMapKeys(pdump)

	var lastStage string

	//Loop over stages to find last successful one with at least one parser
	for i := len(stages) - 2; i >= 0; i-- {
		if len(pdump[stages[i]]) != 0 {
			lastStage = stages[i]
			break
		}
	}

	parsers := make([]string, 0, len(pdump[lastStage]))

	for k := range pdump[lastStage] {
		parsers = append(parsers, k)
	}

	sort.Strings(parsers)

	if len(parsers) == 0 {
		return nil, fmt.Errorf("no parser found. Please install the appropriate parser and retry")
	}

	lastParser := parsers[len(parsers)-1]

	for idx, result := range pdump[lastStage][lastParser] {
		if result.Evt.StrTime == "" {
			log.Warningf("Line %d/%d is missing evt.StrTime. It is most likely a mistake as it will prevent your logs to be processed in time-machine/forensic mode.", idx, len(pdump[lastStage][lastParser]))
		} else {
			log.Debugf("Line %d/%d has evt.StrTime set to '%s'", idx, len(pdump[lastStage][lastParser]), result.Evt.StrTime)
		}
	}

	return &pdump, nil
}

type DumpOpts struct {
	Details          bool
	SkipOk           bool
	ShowNotOkParsers bool
}

func DumpTree(parserResults ParserResults, bucketPour BucketPourInfo, opts DumpOpts) {
	//note : we can use line -> time as the unique identifier (of acquisition)
	state := make(map[time.Time]map[string]map[string]ParserResult)
	assoc := make(map[time.Time]string, 0)

	for stage, parsers := range parserResults {
		for parser, results := range parsers {
			for _, parserRes := range results {
				evt := parserRes.Evt
				if _, ok := state[evt.Line.Time]; !ok {
					state[evt.Line.Time] = make(map[string]map[string]ParserResult)
					assoc[evt.Line.Time] = evt.Line.Raw
				}

				if _, ok := state[evt.Line.Time][stage]; !ok {
					state[evt.Line.Time][stage] = make(map[string]ParserResult)
				}

				state[evt.Line.Time][stage][parser] = ParserResult{Evt: evt, Success: parserRes.Success}
			}
		}
	}

	for bname, evtlist := range bucketPour {
		for _, evt := range evtlist {
			if evt.Line.Raw == "" {
				continue
			}

			//it might be bucket overflow being reprocessed, skip this
			if _, ok := state[evt.Line.Time]; !ok {
				state[evt.Line.Time] = make(map[string]map[string]ParserResult)
				assoc[evt.Line.Time] = evt.Line.Raw
			}

			//there is a trick : to know if an event successfully exit the parsers, we check if it reached the pour() phase
			//we thus use a fake stage "buckets" and a fake parser "OK" to know if it entered
			if _, ok := state[evt.Line.Time]["buckets"]; !ok {
				state[evt.Line.Time]["buckets"] = make(map[string]ParserResult)
			}

			state[evt.Line.Time]["buckets"][bname] = ParserResult{Success: true}
		}
	}

	yellow := color.New(color.FgYellow).SprintFunc()
	red := color.New(color.FgRed).SprintFunc()
	green := color.New(color.FgGreen).SprintFunc()
	whitelistReason := ""
	//get each line
	for tstamp, rawstr := range assoc {
		if opts.SkipOk {
			if _, ok := state[tstamp]["buckets"]["OK"]; ok {
				continue
			}
		}

		fmt.Printf("line: %s\n", rawstr)

		skeys := make([]string, 0, len(state[tstamp]))

		for k := range state[tstamp] {
			//there is a trick : to know if an event successfully exit the parsers, we check if it reached the pour() phase
			//we thus use a fake stage "buckets" and a fake parser "OK" to know if it entered
			if k == "buckets" {
				continue
			}

			skeys = append(skeys, k)
		}

		sort.Strings(skeys)

		// iterate stage
		var prevItem types.Event

		for _, stage := range skeys {
			parsers := state[tstamp][stage]

			sep := "├"
			presep := "|"

			fmt.Printf("\t%s %s\n", sep, stage)

			pkeys := sortedMapKeys(parsers)

			for idx, parser := range pkeys {
				res := parsers[parser].Success
				sep := "├"

				if idx == len(pkeys)-1 {
					sep = "└"
				}

				created := 0
				updated := 0
				deleted := 0
				whitelisted := false
				changeStr := ""
				detailsDisplay := ""

				if res {
					changelog, _ := diff.Diff(prevItem, parsers[parser].Evt)
					for _, change := range changelog {
						switch change.Type {
						case "create":
							created++

							detailsDisplay += fmt.Sprintf("\t%s\t\t%s %s evt.%s : %s\n", presep, sep, change.Type, strings.Join(change.Path, "."), green(change.To))
						case "update":
							detailsDisplay += fmt.Sprintf("\t%s\t\t%s %s evt.%s : %s -> %s\n", presep, sep, change.Type, strings.Join(change.Path, "."), change.From, yellow(change.To))

							if change.Path[0] == "Whitelisted" && change.To == true {
								whitelisted = true

								if whitelistReason == "" {
									whitelistReason = parsers[parser].Evt.WhitelistReason
								}
							}
							updated++
						case "delete":
							deleted++

							detailsDisplay += fmt.Sprintf("\t%s\t\t%s %s evt.%s\n", presep, sep, change.Type, red(strings.Join(change.Path, ".")))
						}
					}

					prevItem = parsers[parser].Evt
				}

				if created > 0 {
					changeStr += green(fmt.Sprintf("+%d", created))
				}

				if updated > 0 {
					if len(changeStr) > 0 {
						changeStr += " "
					}

					changeStr += yellow(fmt.Sprintf("~%d", updated))
				}

				if deleted > 0 {
					if len(changeStr) > 0 {
						changeStr += " "
					}

					changeStr += red(fmt.Sprintf("-%d", deleted))
				}

				if whitelisted {
					if len(changeStr) > 0 {
						changeStr += " "
					}

					changeStr += red("[whitelisted]")
				}

				if changeStr == "" {
					changeStr = yellow("unchanged")
				}

				if res {
					fmt.Printf("\t%s\t%s %s %s (%s)\n", presep, sep, emoji.GreenCircle, parser, changeStr)

					if opts.Details {
						fmt.Print(detailsDisplay)
					}
				} else if opts.ShowNotOkParsers {
					fmt.Printf("\t%s\t%s %s %s\n", presep, sep, emoji.RedCircle, parser)
				}
			}
		}

		sep := "└"

		if len(state[tstamp]["buckets"]) > 0 {
			sep = "├"
		}

		//did the event enter the bucket pour phase ?
		if _, ok := state[tstamp]["buckets"]["OK"]; ok {
			fmt.Printf("\t%s-------- parser success %s\n", sep, emoji.GreenCircle)
		} else if whitelistReason != "" {
			fmt.Printf("\t%s-------- parser success, ignored by whitelist (%s) %s\n", sep, whitelistReason, emoji.GreenCircle)
		} else {
			fmt.Printf("\t%s-------- parser failure %s\n", sep, emoji.RedCircle)
		}

		//now print bucket info
		if len(state[tstamp]["buckets"]) > 0 {
			fmt.Printf("\t├ Scenarios\n")
		}

		bnames := make([]string, 0, len(state[tstamp]["buckets"]))

		for k := range state[tstamp]["buckets"] {
			//there is a trick : to know if an event successfully exit the parsers, we check if it reached the pour() phase
			//we thus use a fake stage "buckets" and a fake parser "OK" to know if it entered
			if k == "OK" {
				continue
			}

			bnames = append(bnames, k)
		}

		sort.Strings(bnames)

		for idx, bname := range bnames {
			sep := "├"
			if idx == len(bnames)-1 {
				sep = "└"
			}

			fmt.Printf("\t\t%s %s %s\n", sep, emoji.GreenCircle, bname)
		}

		fmt.Println()
	}
}