package checker

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"time"

	sdk "git.happydns.org/checker-sdk-go/checker"
)

const threatFoxEndpoint = "https://threatfox-api.abuse.ch/api/v1/"

func init() { Register(&threatFoxSource{endpoint: threatFoxEndpoint}) }

type threatFoxSource struct {
	endpoint string
}

func (*threatFoxSource) ID() string   { return "threatfox" }
func (*threatFoxSource) Name() string { return "abuse.ch ThreatFox" }

func (*threatFoxSource) Options() SourceOptions {
	return SourceOptions{
		Admin: []sdk.CheckerOptionField{
			{
				Id:          "threatfox_auth_key",
				Type:        "string",
				Label:       "ThreatFox Auth-Key",
				Description: "abuse.ch ThreatFox Auth-Key (free, requires an abuse.ch account). Without this key the source is disabled.",
				Secret:      true,
			},
		},
		User: []sdk.CheckerOptionField{
			{
				Id:          "enable_threatfox",
				Type:        "bool",
				Label:       "Use abuse.ch ThreatFox",
				Description: "Query ThreatFox for indicators of compromise (C2 servers, malware, phishing) associated with the domain.",
				Default:     true,
			},
		},
	}
}

func (s *threatFoxSource) Query(ctx context.Context, domain, registered string, opts sdk.CheckerOptions) []SourceResult {
	authKey := stringOpt(opts, "threatfox_auth_key")
	if !sdk.GetBoolOption(opts, "enable_threatfox", true) || registered == "" || authKey == "" {
		return []SourceResult{{SourceID: s.ID(), SourceName: s.Name(), Enabled: false}}
	}

	res := SourceResult{
		SourceID: s.ID(), SourceName: s.Name(), Enabled: true,
		Reference: "https://threatfox.abuse.ch/browse/",
	}

	buf, err := json.Marshal(map[string]any{
		"query":       "search_ioc",
		"search_term": registered,
	})
	if err != nil {
		res.Error = err.Error()
		return []SourceResult{res}
	}

	reqCtx, cancel := context.WithTimeout(ctx, 15*time.Second)
	defer cancel()

	req, err := http.NewRequestWithContext(reqCtx, http.MethodPost, s.endpoint, bytes.NewReader(buf))
	if err != nil {
		res.Error = err.Error()
		return []SourceResult{res}
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Auth-Key", authKey)

	body, status, err := httpDo(req, 4<<20)
	if err != nil {
		res.Error = err.Error()
		return []SourceResult{res}
	}
	if status != http.StatusOK {
		res.Error = fmt.Sprintf("HTTP %d: %s", status, truncate(string(body), 200))
		return []SourceResult{res}
	}

	var parsed struct {
		QueryStatus string `json:"query_status"`
		Data        []struct {
			IOCValue          string   `json:"ioc_value"`
			IOCType           string   `json:"ioc_type"`
			ThreatType        string   `json:"threat_type"`
			MalwarePrintable  string   `json:"malware_printable"`
			ConfidenceLevel   int      `json:"confidence_level"`
			FirstSeen         string   `json:"first_seen"`
			LastSeen          string   `json:"last_seen"`
		} `json:"data"`
	}
	if err := json.Unmarshal(body, &parsed); err != nil {
		res.Error = "decode: " + err.Error()
		return []SourceResult{res}
	}

	switch parsed.QueryStatus {
	case "ok":
		threats := map[string]bool{}
		for _, ioc := range parsed.Data {
			label := ioc.MalwarePrintable
			if label == "" {
				label = ioc.ThreatType
			}
			if label != "" && !threats[label] {
				threats[label] = true
				res.Reasons = append(res.Reasons, label)
			}
			res.Evidence = append(res.Evidence, Evidence{
				Label:  "IOC",
				Value:  ioc.IOCValue,
				Status: ioc.ThreatType,
				Extra: map[string]string{
					"malware":    ioc.MalwarePrintable,
					"confidence": fmt.Sprintf("%d%%", ioc.ConfidenceLevel),
					"first_seen": ioc.FirstSeen,
				},
			})
		}
	case "no_result":
		// Clean.
	default:
		res.Error = "query_status=" + parsed.QueryStatus
	}
	return []SourceResult{res}
}

func (*threatFoxSource) Evaluate(r SourceResult) (bool, string) {
	if r.Enabled && r.Error == "" && len(r.Evidence) > 0 {
		return true, SeverityCrit
	}
	return false, ""
}

func (*threatFoxSource) Diagnose(res SourceResult) Diagnosis {
	return Diagnosis{
		Severity: SeverityCrit,
		Title:    "Listed in abuse.ch ThreatFox as a threat IOC",
		Detail: fmt.Sprintf(
			"%d IOC(s) match this domain; threat(s): %s. ThreatFox tracks indicators of compromise including C2 servers, malware distribution hosts, and phishing infrastructure. Treat the host as compromised or abused: investigate recent DNS changes, audit hosted content, then request removal through the ThreatFox reference page.",
			len(res.Evidence), joinNonEmpty(res.Reasons, ", "),
		),
		Fix:      res.Reference,
		FixIsURL: res.Reference != "",
	}
}