package security

import (
	"regexp"
	"strings"
)

const (
	// MaxTicketPromptRunes caps subject+body text embedded in LLM prompts.
	MaxTicketPromptRunes = 6000
	// MaxKBSnippetRunes caps each KB snippet passed to the model.
	MaxKBSnippetRunes = 2000
	// MaxKBSnippets caps how many snippets may accompany one ticket prompt.
	MaxKBSnippets = 5
)

// Secret patterns beyond campaign prompt soft-filters (ticket bodies are untrusted).
var (
	reTicketBearer = regexp.MustCompile(`(?i)\b(Bearer|Basic)\s+[A-Za-z0-9\-._~+/]+=*`)
	reTicketAssign = regexp.MustCompile(`(?i)\b((?:api[_-]?key|access[_-]?token|secret(?:_key)?|password|passwd|authorization|credential|private[_-]?key)\s*[=:]\s*)["']?[^\s"',}\]]+["']?`)
	reTicketStripe = regexp.MustCompile(`\b(sk_live_|sk_test_|rk_live_|rk_test_|whsec_|pk_live_|pk_test_)[A-Za-z0-9]+`)
	reTicketOpenAI = regexp.MustCompile(`\bsk-[A-Za-z0-9]{20,}`)
	reTicketAWS    = regexp.MustCompile(`\b(AKIA[0-9A-Z]{16}|ASIA[0-9A-Z]{16})\b`)
	reTicketPEM    = regexp.MustCompile(`(?s)-----BEGIN [A-Z0-9 ]*PRIVATE KEY-----.*?-----END [A-Z0-9 ]*PRIVATE KEY-----`)
	reTicketDSN    = regexp.MustCompile(`(?i)\b((?:mysql|postgres|postgresql|redis|rediss|mongodb):\/\/)[^@\s]+@`)
	reTicketJWT    = regexp.MustCompile(`\beyJ[A-Za-z0-9_-]{20,}\.[A-Za-z0-9_-]{10,}\.[A-Za-z0-9_-]{10,}`)
	reTicketInject = regexp.MustCompile(`(?i)(ignore\s+(all\s+)?(previous|prior|above)\s+(instructions?|prompts?|rules?)|disregard\s+(all\s+)?(previous|prior)|system\s*:|assistant\s*:|<\s*/?\s*script|\[\s*INST\s*\]|<<\s*SYS\s*>>)`)
)

// RedactSecrets strips common secret material from untrusted ticket text before
// match features, prompts, or structured logs. Fail-soft: never panics.
func RedactSecrets(s string) (out string) {
	defer func() {
		if recover() != nil {
			out = "[REDACTED]"
		}
	}()
	out = s
	out = reTicketPEM.ReplaceAllString(out, "[REDACTED_PEM]")
	out = reTicketBearer.ReplaceAllString(out, "[REDACTED_AUTH]")
	out = reTicketAssign.ReplaceAllString(out, "${1}[REDACTED]")
	out = reTicketStripe.ReplaceAllString(out, "[REDACTED]")
	out = reTicketOpenAI.ReplaceAllString(out, "[REDACTED]")
	out = reTicketAWS.ReplaceAllString(out, "[REDACTED]")
	out = reTicketJWT.ReplaceAllString(out, "[REDACTED]")
	out = reTicketDSN.ReplaceAllString(out, "${1}[REDACTED]@")
	return out
}

// SanitizeUntrustedTicketText redacts secrets, soft-filters injection phrases,
// strips controls, and truncates. Use for any ticket subject/body entering a prompt.
func SanitizeUntrustedTicketText(s string, maxRunes int) string {
	if maxRunes <= 0 {
		maxRunes = MaxTicketPromptRunes
	}
	s = RedactSecrets(s)
	s = stripControls(strings.TrimSpace(s))
	s = reTicketInject.ReplaceAllString(s, "[filtered]")
	s = injectPhrase.ReplaceAllString(s, "[filtered]")
	return TruncateRunes(s, maxRunes)
}

// WrapUntrustedData delimits untrusted customer content so models treat it as data,
// not instructions. Content must already be sanitized.
func WrapUntrustedData(label, content string) string {
	label = strings.TrimSpace(label)
	if label == "" {
		label = "untrusted"
	}
	label = strings.Map(func(r rune) rune {
		if r == '<' || r == '>' {
			return '-'
		}
		return r
	}, label)
	var b strings.Builder
	b.WriteString("<<<UNTRUSTED_")
	b.WriteString(strings.ToUpper(label))
	b.WriteString("_START>>>\n")
	b.WriteString(content)
	b.WriteString("\n<<<UNTRUSTED_")
	b.WriteString(strings.ToUpper(label))
	b.WriteString("_END>>>")
	return b.String()
}

// SanitizeKBSnippet bounds and lightly sanitizes platform KB text for prompts.
// KB is admin-authored (trusted relative to tickets) but still length-capped.
func SanitizeKBSnippet(s string) string {
	return SanitizePrompt(s, MaxKBSnippetRunes)
}