# app/modules/dev_tools/services/isolation_audit_service.py
"""
Tenant Isolation Audit Service

Scans all stores and reports where configuration values come from —
flagging silent inheritance, missing data, and potential data commingling
in the multi-tenant system.
"""

import logging

from sqlalchemy.orm import Session, joinedload

logger = logging.getLogger(__name__)


def run_isolation_audit(
    db: Session,
    store_code: str | None = None,
    risk_filter: str | None = None,
) -> dict:
    """
    Audit tenant isolation across all (or one) store(s).

    Args:
        db: Database session
        store_code: Optional filter to a single store
        risk_filter: Optional 'critical', 'high', or 'medium'

    Returns:
        dict with total_stores, stores_with_findings, summary, results
    """
    from app.modules.billing.models.merchant_subscription import MerchantSubscription
    from app.modules.tenancy.models import Store
    from app.modules.tenancy.models.admin import AdminSetting
    from app.modules.tenancy.models.merchant_domain import MerchantDomain

    # ── Pre-fetch stores with eager-loaded relationships ──
    query = (
        db.query(Store)
        .options(
            joinedload(Store.merchant),
            joinedload(Store.store_platforms),
            joinedload(Store.domains),
            joinedload(Store.store_theme),
        )
        .filter(Store.is_active.is_(True))
    )
    if store_code:
        query = query.filter(Store.store_code == store_code)

    stores = query.all()

    # ── Batch-load MerchantSubscription indexed by (merchant_id, platform_id) ──
    all_subs = db.query(MerchantSubscription).all()
    subs_map: dict[tuple[int, int], MerchantSubscription] = {}
    for sub in all_subs:
        subs_map[(sub.merchant_id, sub.platform_id)] = sub

    # ── Batch-load MerchantDomain indexed by merchant_id ──
    all_merchant_domains = db.query(MerchantDomain).all()
    merchant_domains_map: dict[int, list[MerchantDomain]] = {}
    for md in all_merchant_domains:
        merchant_domains_map.setdefault(md.merchant_id, []).append(md)

    # ── Pre-fetch default_storefront_locale from AdminSetting ──
    default_locale_setting = (
        db.query(AdminSetting)
        .filter(AdminSetting.key == "default_storefront_locale")
        .first()
    )
    default_locale = default_locale_setting.value if default_locale_setting else None

    # ── Run checkers per store ──
    results = []
    summary = {"critical": 0, "high": 0, "medium": 0}

    for store in stores:
        merchant_domains = merchant_domains_map.get(store.merchant_id, [])
        findings: list[dict] = []

        findings.extend(_check_contact_inheritance(store))
        findings.extend(_check_domain_resolution(store, merchant_domains))
        findings.extend(_check_subscription_coverage(store, subs_map))
        findings.extend(_check_merchant_active(store))
        findings.extend(_check_merchant_domain_primary(merchant_domains))
        findings.extend(_check_theme_fallback(store))
        findings.extend(_check_locale_fallback(store, default_locale))
        findings.extend(_check_language_config(store))

        # Apply risk filter
        if risk_filter:
            findings = [f for f in findings if f["risk"] == risk_filter]

        # Count by risk
        finding_counts = {"critical": 0, "high": 0, "medium": 0}
        for f in findings:
            finding_counts[f["risk"]] = finding_counts.get(f["risk"], 0) + 1
            summary[f["risk"]] = summary.get(f["risk"], 0) + 1

        results.append({
            "store_code": store.store_code,
            "store_name": store.name,
            "merchant_name": store.merchant.name if store.merchant else None,
            "finding_counts": finding_counts,
            "findings": findings,
        })

    stores_with_findings = sum(1 for r in results if r["findings"])

    return {
        "total_stores": len(results),
        "stores_with_findings": stores_with_findings,
        "summary": summary,
        "results": results,
    }


# ── Checker functions ──


def _finding(
    check: str,
    check_label: str,
    risk: str,
    resolved_value: str | None,
    source: str,
    source_label: str,
    is_explicit: bool,
    note: str = "",
) -> dict:
    return {
        "check": check,
        "check_label": check_label,
        "risk": risk,
        "resolved_value": resolved_value,
        "source": source,
        "source_label": source_label,
        "is_explicit": is_explicit,
        "note": note,
    }


_CONTACT_FIELDS = [
    ("contact_email", "Contact Email"),
    ("contact_phone", "Contact Phone"),
    ("website", "Website"),
    ("business_address", "Business Address"),
    ("tax_number", "Tax Number"),
]


def _check_contact_inheritance(store) -> list[dict]:
    """Check 5 contact fields: store value → merchant fallback → none."""
    findings = []
    merchant = store.merchant

    for field, label in _CONTACT_FIELDS:
        store_val = getattr(store, field, None)
        merchant_val = getattr(merchant, field, None) if merchant else None

        if store_val:
            # Explicitly set on store — no finding
            continue
        if merchant_val:
            findings.append(_finding(
                check=field,
                check_label=label,
                risk="critical",
                resolved_value=str(merchant_val),
                source="merchant",
                source_label=f"Inherited from merchant '{merchant.name}'",
                is_explicit=False,
                note="Store has no own value; silently falls back to merchant",
            ))
        else:
            findings.append(_finding(
                check=field,
                check_label=label,
                risk="critical",
                resolved_value=None,
                source="none",
                source_label="No value anywhere",
                is_explicit=False,
                note="Neither store nor merchant has this value set",
            ))

    return findings


def _check_domain_resolution(store, merchant_domains: list) -> list[dict]:
    """Check effective_domain: StoreDomain → MerchantDomain → subdomain fallback."""
    findings = []

    # Check if store has its own active domain
    store_domains = [d for d in (store.domains or []) if d.is_active]
    active_merchant_domains = [d for d in merchant_domains if d.is_active]

    if store_domains:
        # Store has its own domain — explicit, no finding
        return findings

    if active_merchant_domains:
        primary = next((d for d in active_merchant_domains if d.is_primary), None)
        domain_val = primary.domain if primary else active_merchant_domains[0].domain
        findings.append(_finding(
            check="effective_domain",
            check_label="Effective Domain",
            risk="critical",
            resolved_value=domain_val,
            source="merchant",
            source_label="Using merchant domain (shared with other stores)",
            is_explicit=False,
            note="No store-specific domain; merchant domain may serve wrong store",
        ))
    else:
        findings.append(_finding(
            check="effective_domain",
            check_label="Effective Domain",
            risk="critical",
            resolved_value=f"{store.subdomain}.* (subdomain fallback)",
            source="hardcoded",
            source_label="Subdomain fallback only",
            is_explicit=False,
            note="No custom domain at store or merchant level",
        ))

    return findings


def _check_subscription_coverage(store, subs_map: dict) -> list[dict]:
    """For each StorePlatform membership, verify a MerchantSubscription exists and is active."""
    findings = []

    for sp in (store.store_platforms or []):
        if not sp.is_active:
            continue

        key = (store.merchant_id, sp.platform_id)
        sub = subs_map.get(key)

        if not sub:
            findings.append(_finding(
                check=f"subscription_{sp.platform_id}",
                check_label=f"Subscription (platform {sp.platform_id})",
                risk="critical",
                resolved_value=None,
                source="none",
                source_label="No subscription found",
                is_explicit=False,
                note=f"Store active on platform {sp.platform_id} but merchant has no subscription",
            ))
        elif not sub.is_active:
            findings.append(_finding(
                check=f"subscription_{sp.platform_id}",
                check_label=f"Subscription (platform {sp.platform_id})",
                risk="critical",
                resolved_value=sub.status,
                source="merchant",
                source_label=f"Subscription exists but status='{sub.status}'",
                is_explicit=False,
                note="Store active on platform but subscription is not active",
            ))

    return findings


def _check_merchant_active(store) -> list[dict]:
    """Merchant inactive but store still active."""
    merchant = store.merchant
    if not merchant or merchant.is_active:
        return []

    return [_finding(
        check="merchant_active",
        check_label="Merchant Active",
        risk="high",
        resolved_value=str(merchant.is_active),
        source="merchant",
        source_label=f"Merchant '{merchant.name}' is inactive",
        is_explicit=True,
        note="Store is active but its parent merchant is inactive",
    )]


def _check_merchant_domain_primary(merchant_domains: list) -> list[dict]:
    """Multiple MerchantDomains marked primary — non-deterministic resolution."""
    primary_domains = [d for d in merchant_domains if d.is_primary and d.is_active]

    if len(primary_domains) <= 1:
        return []

    domain_list = ", ".join(d.domain for d in primary_domains)
    return [_finding(
        check="merchant_domain_primary",
        check_label="Merchant Primary Domain",
        risk="high",
        resolved_value=domain_list,
        source="merchant",
        source_label=f"{len(primary_domains)} domains marked as primary",
        is_explicit=True,
        note="Multiple primary domains cause non-deterministic resolution",
    )]


def _check_theme_fallback(store) -> list[dict]:
    """No active store_theme — falls back to hardcoded default."""
    theme = store.store_theme

    if theme and theme.is_active:
        return []

    return [_finding(
        check="store_theme",
        check_label="Store Theme",
        risk="medium",
        resolved_value="default (hardcoded)",
        source="hardcoded",
        source_label="No active theme configured",
        is_explicit=False,
        note="Falls back to hardcoded default theme" if not theme else "Theme exists but is inactive",
    )]


def _check_locale_fallback(store, default_locale: str | None) -> list[dict]:
    """storefront_locale is NULL — falls back to platform default or 'fr-LU'."""
    if store.storefront_locale:
        return []

    fallback = default_locale or "fr-LU"
    source = "platform_default" if default_locale else "hardcoded"
    source_label = (
        f"Platform default: '{default_locale}'"
        if default_locale
        else "Hardcoded fallback 'fr-LU'"
    )

    return [_finding(
        check="storefront_locale",
        check_label="Storefront Locale",
        risk="medium",
        resolved_value=fallback,
        source=source,
        source_label=source_label,
        is_explicit=False,
        note="storefront_locale is NULL; using fallback",
    )]


_DEFAULT_LANGUAGES = ["fr", "de", "en", "lb"]


def _check_language_config(store) -> list[dict]:
    """storefront_languages matches column default — may never have been explicitly set."""
    languages = store.storefront_languages

    if languages and languages != _DEFAULT_LANGUAGES:
        return []

    return [_finding(
        check="storefront_languages",
        check_label="Storefront Languages",
        risk="medium",
        resolved_value=str(languages or _DEFAULT_LANGUAGES),
        source="hardcoded",
        source_label="Column default value",
        is_explicit=False,
        note="Matches column default — may never have been explicitly configured",
    )]