"""
scorer.py - Severity scoring for credential hits.

Scoring logic (highest match wins):

  CRITICAL - Employee credentials (internal email domain)
                e.g. jdoe@yourclinic.cl:password
 - Admin/privileged service URLs
                e.g. admin., vpn., ssh., rdp., gitlab., jira.

  HIGH - Internal-facing services
                e.g. intranet., erp., crm., portal., citrix.
 - Password manager or SSO hits
 - Any credential where username looks like an employee email

  MEDIUM - Client-facing portals
                e.g. app., patient., client., booking.
 - Domain match on a non-privileged service

  LOW - Generic domain keyword match
 - No URL parsed, just a raw domain mention

Each scored hit gets a dict with:
  - severity:    CRITICAL / HIGH / MEDIUM / LOW
  - score:       int (higher = worse)
  - reasons:     list of human-readable reasons
  - raw:         original line
"""

import re
import logging
from dataclasses import dataclass, field
import config as _config

log = logging.getLogger(__name__)


# ─── Severity levels ─────────────────────────────────────────────────────────

CRITICAL = "CRITICAL"
HIGH     = "HIGH"
MEDIUM   = "MEDIUM"
LOW      = "LOW"

SEVERITY_SCORES = {
    CRITICAL: 40,
    HIGH:     30,
    MEDIUM:   20,
    LOW:      10,
}

SEVERITY_EMOJI = {
    CRITICAL: "🔴",
    HIGH:     "🟠",
    MEDIUM:   "🟡",
    LOW:      "🟢",
}


# ─── Pattern banks ───────────────────────────────────────────────────────────

# Subdomains/services that indicate privileged access
CRITICAL_SERVICES = re.compile(
    r"(?:^|https?://|\.)"
    r"(admin|vpn|ssh|rdp|ftp|sftp|gitlab|github|bitbucket|jenkins|"
    r"jira|confluence|grafana|kibana|sentry|vault|bastion|jump|"
    r"firewall|router|switch|proxy|ldap|ad\.|activedirectory|"
    r"exchange|mail\.)",
    re.IGNORECASE
)

HIGH_SERVICES = re.compile(
    r"(?:^|https?://|\.)"
    r"(intranet|erp|crm|portal|citrix|workspace|webmail|owa|"
    r"sharepoint|teams|slack|zoom|meet|sso|login|auth|oauth|"
    r"accounts?|dashboard|internal|corp|staff|hr|payroll|"
    r"finance|accounting)",
    re.IGNORECASE
)

MEDIUM_SERVICES = re.compile(
    r"(?:^|https?://|\.)"
    r"(app|patient|client|customer|booking|appointment|"
    r"reserva|cita|paciente|user|member|registro|signup|"
    r"support|helpdesk|ticket)",
    re.IGNORECASE
)

# Looks like a corporate email (user@domain)
EMAIL_PATTERN = re.compile(r"[a-zA-Z0-9._%+\-]+@([a-zA-Z0-9.\-]+\.[a-zA-Z]{2,})")

# ULP line parser
# Separator set: colon, semicolon, comma, pipe, tab.
# URL field: optional scheme (http/https/ftp) consumed first so '://' is never
# mistaken for a separator; then an optional port group ':\d+/' absorbs port+path
# (port is digits immediately followed by '/') so 'http://host:88/path:user:pass'
# yields url='http://host:88/path', not url='http'.
ULP_PATTERN = re.compile(
    r"^(?P<url>"
        r"(?:(?:https?|ftp)://)?[^\s:;,|\t]+"  # optional scheme + host/path
        r"(?::\d+/[^\s:;,|\t]*)?"              # optional :port/path (port = digits then /)
    r")"
    r"(?:[:;,|\t])"
    r"(?P<username>[^\s:;,|\t]+)"
    r"(?:[:;,|\t])"
    r"(?P<password>.+)$"
)


# ─── Derived from config ──────────────────────────────────────────────────────

def _kw_to_domain(kw: str) -> str:
    """Strip regex syntax from a keyword to get a plain domain string."""
    return kw.replace(r"@", "").replace(r"\.", ".").strip("^$").lstrip(".")


def _build_employee_domains() -> list[tuple[str, re.Pattern]]:
    """
    Keywords that contain '@' are employee email domain patterns.

    Pattern anchors at '@<domain>' so that a URL containing the org domain
    never causes a false CRITICAL on an unrelated email like @gmail.com.

    Returns list of (domain_str, compiled_pattern) tuples.
    """
    patterns = []
    for kw in _config.TARGET_KEYWORDS:
        if "@" in kw:
            domain = _kw_to_domain(kw)
            if domain:
                pat = re.compile(
                    r"@" + re.escape(domain) + r"(?:[^a-zA-Z0-9.\-]|$)",
                    re.IGNORECASE,
                )
                patterns.append((domain, pat))
    return patterns

EMPLOYEE_DOMAINS = _build_employee_domains()


def _build_org_domains() -> list[re.Pattern]:
    """
    All keywords as plain domain patterns for the LOW baseline match.
    Checks that the org domain appears anywhere in the line.
    """
    patterns = []
    for kw in _config.TARGET_KEYWORDS:
        domain = _kw_to_domain(kw)
        if domain:
            patterns.append(re.compile(re.escape(domain), re.IGNORECASE))
    return patterns

ORG_DOMAINS = _build_org_domains()


def reload_from_config() -> None:
    """
    Rebuild EMPLOYEE_DOMAINS and ORG_DOMAINS from the current config.TARGET_KEYWORDS.
    Call after save_runtime_config() updates the keyword list.
    """
    global EMPLOYEE_DOMAINS, ORG_DOMAINS
    EMPLOYEE_DOMAINS = _build_employee_domains()
    ORG_DOMAINS      = _build_org_domains()



# ─── Scoring logic ────────────────────────────────────────────────────────────

@dataclass
class ScoredHit:
    raw:      str
    severity: str
    score:    int
    reasons:  list[str] = field(default_factory=list)
    url:      str | None = None
    username: str | None = None
    password: str | None = None

    @property
    def emoji(self) -> str:
        return SEVERITY_EMOJI.get(self.severity, "⚪")

    def __str__(self) -> str:
        return f"{self.emoji} [{self.severity}] {self.raw}"


def score_hit(line: str) -> ScoredHit:
    """
    Score a single credential line.
    Returns a ScoredHit with severity, score, and reasons.
    """
    line    = line.strip()
    reasons = []
    scores  = []

    # Parse ULP fields if possible
    url = username = password = None
    m = ULP_PATTERN.match(line)
    if m:
        url      = m.group("url")
        username = m.group("username")
        password = m.group("password")

    # ── Check 1: Employee email domain in username or line ───────────────
    # EMPLOYEE_DOMAINS entries are (domain_str, pattern) where the pattern
    # requires '@' immediately before the domain, so a URL containing the
    # org domain never triggers a CRITICAL on an unrelated email (@gmail etc).
    for domain_str, pat in EMPLOYEE_DOMAINS:
        # Try the parsed username field first; fall back to full line.
        # Either way the pattern requires a literal '@' before the domain.
        field = username if username else ""
        if not pat.search(field):
            field = line
        if pat.search(field):
            scores.append(CRITICAL)
            reasons.append(f"Employee email domain: {domain_str}")
            break

    # ── Check 2: Is the URL a privileged/critical service? ────────────────
    if url and CRITICAL_SERVICES.search(url):
        scores.append(CRITICAL)
        reasons.append(f"Critical service URL: {url}")

    # ── Check 3: Is the URL a high-value internal service? ────────────────
    if url and HIGH_SERVICES.search(url):
        scores.append(HIGH)
        reasons.append(f"High-value internal service: {url}")

    # ── Check 4: Is the URL a client-facing service? ──────────────────────
    if url and MEDIUM_SERVICES.search(url):
        scores.append(MEDIUM)
        reasons.append(f"Client-facing service: {url}")

    # ── Check 5: Generic org domain match (baseline) ─────────────────────
    for pattern in ORG_DOMAINS:
        if pattern.search(line):
            if not scores:
                scores.append(LOW)
                reasons.append(f"Org domain match in line")
            break

    # ── Check 6: Weak/empty password flag ────────────────────────────────
    if password:
        if len(password) <= 6:
            reasons.append(f"⚠ Weak password ({len(password)} chars)")
        if password.lower() in {"123456", "password", "qwerty", "111111", "admin", "letmein"}:
            reasons.append(f"⚠ Common password: {password}")

    # ── Resolve final severity ────────────────────────────────────────────
    severity_order = [CRITICAL, HIGH, MEDIUM, LOW]
    final_severity = LOW  # default
    for s in severity_order:
        if s in scores:
            final_severity = s
            break

    if not reasons:
        reasons.append("Pattern match")

    return ScoredHit(
        raw      = line,
        severity = final_severity,
        score    = SEVERITY_SCORES[final_severity],
        reasons  = reasons,
        url      = url,
        username = username,
        password = password,
    )


def score_hits(lines: list[str]) -> list[ScoredHit]:
    """Score a list of credential lines. Returns sorted by score descending."""
    scored = [score_hit(line) for line in lines]
    scored.sort(key=lambda h: h.score, reverse=True)
    return scored


def summarize(scored: list[ScoredHit]) -> dict:
    """Count hits by severity level."""
    summary = {CRITICAL: 0, HIGH: 0, MEDIUM: 0, LOW: 0}
    for h in scored:
        summary[h.severity] += 1
    return summary