package vuln

import (
	"strings"
)

// Finding mirrors agent vuln_findings JSON for server-side enrichment.
type Finding struct {
	CVEID                     string `json:"cve_id"`
	Severity                  string `json:"severity"`
	Component                 string `json:"component"`
	Patched                   bool   `json:"patched"`
	ExploitableInFleetContext bool   `json:"exploitable_in_fleet_context"`
	Detail                    string `json:"detail,omitempty"`
}

// CatalogEntry is a lightweight embedded CVE rule for fleet correlator.
type CatalogEntry struct {
	ID         string `json:"id"`
	Name       string `json:"name"`
	Component  string `json:"component"`
	Severity   string `json:"severity"`
	FleetPorts []int  `json:"fleet_ports,omitempty"`
	PatchKBs   []string `json:"patch_kbs,omitempty"`
}

// EmbeddedCatalog is served by GET /api/v1/vuln/catalog (cached JSON).
var EmbeddedCatalog = []CatalogEntry{
	{ID: "CVE-2021-44228", Name: "Log4Shell", Component: "Apache Log4j", Severity: "critical"},
	{ID: "CVE-2021-26855", Name: "ProxyLogon", Component: "Microsoft Exchange", Severity: "critical", FleetPorts: []int{443, 80}, PatchKBs: []string{"KB5000871"}},
	{ID: "CVE-2020-1472", Name: "Zerologon", Component: "Microsoft Netlogon", Severity: "critical", FleetPorts: []int{445, 135}, PatchKBs: []string{"KB4577015"}},
	{ID: "CVE-2019-19781", Name: "Citrix ADC", Component: "Citrix ADC/Gateway", Severity: "critical", FleetPorts: []int{443}},
	{ID: "CVE-2019-11510", Name: "Pulse Secure", Component: "Ivanti Pulse Connect Secure", Severity: "critical", FleetPorts: []int{443}},
	{ID: "CVE-2020-5902", Name: "F5 BIG-IP", Component: "F5 BIG-IP", Severity: "critical", FleetPorts: []int{443, 8443}},
	{ID: "CVE-2022-1388", Name: "F5 iControl", Component: "F5 BIG-IP", Severity: "critical", FleetPorts: []int{443, 8443}},
	{ID: "CVE-2021-26084", Name: "Confluence OGNL", Component: "Atlassian Confluence", Severity: "critical", FleetPorts: []int{8090, 8443}},
	{ID: "CVE-2022-26134", Name: "Confluence RCE", Component: "Atlassian Confluence", Severity: "critical", FleetPorts: []int{8090, 8443}},
	{ID: "CVE-2021-40539", Name: "ManageEngine", Component: "Zoho ManageEngine ADSelfService Plus", Severity: "critical", FleetPorts: []int{9251}},
	{ID: "CVE-2018-13379", Name: "FortiOS path traversal", Component: "Fortinet FortiGate/FortiOS", Severity: "critical", FleetPorts: []int{443, 10443}},
	{ID: "CVE-2021-34527", Name: "PrintNightmare", Component: "Windows Print Spooler", Severity: "high", FleetPorts: []int{445, 135}, PatchKBs: []string{"KB5004945"}},
	{ID: "CVE-2020-0688", Name: "Exchange RCE", Component: "Microsoft Exchange", Severity: "high", FleetPorts: []int{443}},
	{ID: "CVE-2021-21972", Name: "vCenter RCE", Component: "VMware vCenter", Severity: "critical", FleetPorts: []int{443}},
}

// FleetContext carries server-known signals for correlator enrichment.
type FleetContext struct {
	ListenPortCount int
	PathTracerPorts []int
	SSHAvailable    bool
	OSVersion       string
}

// EnrichFindings applies fleet-context rules (open ports from Path Tracer when available).
func EnrichFindings(findings []Finding, ctx FleetContext) []Finding {
	if len(findings) == 0 {
		return findings
	}
	portSet := make(map[int]bool)
	for _, p := range ctx.PathTracerPorts {
		portSet[p] = true
	}
	rules := catalogByID()
	out := make([]Finding, len(findings))
	copy(out, findings)
	for i := range out {
		if out[i].Patched || out[i].ExploitableInFleetContext {
			continue
		}
		rule, ok := rules[out[i].CVEID]
		if !ok {
			continue
		}
		for _, p := range rule.FleetPorts {
			if portSet[p] {
				out[i].ExploitableInFleetContext = true
				out[i].Detail = strings.TrimSpace(out[i].Detail + " · Path Tracer hop port " + itoa(p) + " open")
				break
			}
		}
		if !out[i].ExploitableInFleetContext && ctx.SSHAvailable && ctx.ListenPortCount > 0 {
			for _, p := range rule.FleetPorts {
				if p == 22 || p == 445 || p == 443 {
					out[i].ExploitableInFleetContext = true
					out[i].Detail = strings.TrimSpace(out[i].Detail + " · fleet SSH/listener context")
					break
				}
			}
		}
	}
	return out
}

func catalogByID() map[string]CatalogEntry {
	m := make(map[string]CatalogEntry, len(EmbeddedCatalog))
	for _, e := range EmbeddedCatalog {
		m[e.ID] = e
	}
	return m
}

func itoa(n int) string {
	if n == 0 {
		return "0"
	}
	var b [12]byte
	i := len(b)
	for n > 0 {
		i--
		b[i] = byte('0' + n%10)
		n /= 10
	}
	return string(b[i:])
}

// RiskScore computes a 0-100 score from enriched findings.
func RiskScore(findings []Finding) int {
	score := 0
	for _, f := range findings {
		if f.ExploitableInFleetContext {
			if f.Severity == "critical" {
				score += 25
			} else {
				score += 12
			}
		} else if !f.Patched {
			score += 8
		}
	}
	if score > 100 {
		return 100
	}
	return score
}