"""Create deduplicated procurement cases for externally detected internet changes."""

from __future__ import annotations

import json
import logging
from typing import Any, Mapping, Optional

from app.core.config import settings
from app.core.database import execute_query, execute_query_single

logger = logging.getLogger(__name__)

RELEVANT_FIELDS = {
    "address", "service_address", "monthly_cost", "sales_price", "technology",
    "connection_type", "circuit_number", "provider_reference", "provider", "vendor_id",
    "speed_mbps", "download_mbps", "upload_mbps", "status", "sla_subscription_id",
    "sla_price", "sla_status", "ip_range", "cidr", "contract_number", "range_added",
    "range_removed", "range_monthly_cost", "range_sales_price",
}

FIELD_LABELS = {
    "address": "Adresse", "service_address": "Serviceadresse", "monthly_cost": "Indkøbspris",
    "sales_price": "Salgspris", "technology": "Teknologi", "connection_type": "Forbindelsestype",
    "circuit_number": "Kredsløbsnummer", "provider_reference": "Leverandørreference",
    "provider": "Leverandør", "vendor_id": "Leverandør", "speed_mbps": "Hastighed",
    "download_mbps": "Download", "upload_mbps": "Upload", "status": "Status",
    "sla_subscription_id": "SLA-aftale", "sla_price": "SLA-pris", "sla_status": "SLA-status",
    "ip_range": "IP-range", "cidr": "IP-range", "contract_number": "Kontraktnummer",
    "range_added": "Nyt IP-range", "range_removed": "Fjernet IP-range",
    "range_monthly_cost": "IP-range indkøbspris", "range_sales_price": "IP-range salgspris",
}


def filter_relevant_changes(changes: Mapping[str, Any] | None) -> dict[str, dict[str, Any]]:
    filtered: dict[str, dict[str, Any]] = {}
    for field, raw in (changes or {}).items():
        if field not in RELEVANT_FIELDS:
            continue
        change = raw if isinstance(raw, Mapping) else {"from": None, "to": raw}
        before, after = change.get("from"), change.get("to")
        if str(before or "").strip() == str(after or "").strip():
            continue
        filtered[field] = {"from": before, "to": after}
    return filtered


def _procurement_customer_id() -> int:
    configured = getattr(settings, "PROCUREMENT_CASE_CUSTOMER_ID", None)
    if configured:
        row = execute_query_single("SELECT id FROM customers WHERE id=%s AND is_active=true", (configured,))
        if row:
            return int(row["id"])
    row = execute_query_single(
        """SELECT id FROM customers WHERE is_active=true AND LOWER(name) LIKE %s
        ORDER BY CASE WHEN LOWER(name) LIKE %s THEN 0 ELSE 1 END, id LIMIT 1""",
        ("%bmc%", "%bmc networks%"),
    )
    if not row:
        raise ValueError("BMC's interne indkøbskunde blev ikke fundet")
    return int(row["id"])


def _economy_group_id() -> Optional[int]:
    row = execute_query_single(
        """SELECT id FROM groups WHERE LOWER(name) LIKE ANY(%s)
        ORDER BY id LIMIT 1""", (["%økonomi%", "%okonomi%", "%economic%"],),
    )
    return int(row["id"]) if row else None


def _render_description(
    *, connection_id: int, connection_name: str, reference: str, provider: str,
    source_label: str, source_url: Optional[str], changes: Mapping[str, Mapping[str, Any]],
) -> str:
    lines = [
        "Automatisk oprettet efter en ekstern ændring af en internetforbindelse.", "",
        f"Forbindelse: {connection_name}", f"Reference: {reference or '-'}",
        f"Leverandør: {provider or '-'}", f"Kilde: {source_label}",
        f"Link til forbindelse: /economy/internet-connections/{connection_id}",
    ]
    if source_url:
        lines.append(f"Link til kilde: {source_url}")
    lines.extend(["", "Registrerede ændringer:"])
    for field, change in changes.items():
        lines.append(f"- {FIELD_LABELS.get(field, field)}: {change.get('from')} → {change.get('to')}")
    return "\n".join(lines)


def ensure_external_change_case(
    *, connection_id: int, source_type: str, source_key: str, source_label: str,
    changes: Mapping[str, Any], connection_name: str = "Internetforbindelse",
    reference: str = "", provider: str = "", owner_customer_id: Optional[int] = None,
    source_url: Optional[str] = None,
) -> dict[str, Any]:
    relevant = filter_relevant_changes(changes)
    if not relevant:
        return {"case_id": None, "created": False, "changes": {}, "error": None}
    source_type = str(source_type or "external").strip().lower()
    source_key = str(source_key or "").strip()
    if not source_key:
        return {"case_id": None, "created": False, "changes": relevant, "error": "Kilden mangler en stabil nøgle"}

    try:
        existing = execute_query_single(
            """SELECT id, sag_id, changes FROM internet_connection_change_cases
            WHERE connection_id=%s AND source_type=%s AND source_key=%s""",
            (connection_id, source_type, source_key),
        )
        merged = dict((existing or {}).get("changes") or {})
        merged.update(relevant)
        case_customer_id = int(owner_customer_id) if owner_customer_id else _procurement_customer_id()
        title = f"Internetændring {reference or connection_name} · {source_label}"[:255]
        description = _render_description(
            connection_id=connection_id, connection_name=connection_name, reference=reference,
            provider=provider, source_label=source_label, source_url=source_url, changes=merged,
        )
        case_id = int(existing["sag_id"]) if existing and existing.get("sag_id") else None
        created = False
        if case_id:
            execute_query(
                "UPDATE sag_sager SET beskrivelse=%s, updated_at=NOW() WHERE id=%s AND deleted_at IS NULL",
                (description, case_id), fetch=False,
            )
        else:
            row = execute_query_single(
                """INSERT INTO sag_sager
                (titel, beskrivelse, type, status, customer_id, assigned_group_id, created_by_user_id)
                VALUES (%s,%s,'indkøb','åben',%s,%s,1) RETURNING id""",
                (title, description, case_customer_id, _economy_group_id()),
            )
            case_id = int(row["id"])
            created = True

        if existing:
            execute_query(
                """UPDATE internet_connection_change_cases SET sag_id=%s, source_label=%s,
                source_url=%s, changes=%s::jsonb, last_error=NULL, updated_at=NOW() WHERE id=%s""",
                (case_id, source_label, source_url, json.dumps(merged, ensure_ascii=False), existing["id"]), fetch=False,
            )
        else:
            execute_query(
                """INSERT INTO internet_connection_change_cases
                (connection_id,source_type,source_key,source_label,source_url,sag_id,changes)
                VALUES (%s,%s,%s,%s,%s,%s,%s::jsonb)""",
                (connection_id, source_type, source_key, source_label, source_url, case_id,
                 json.dumps(merged, ensure_ascii=False)), fetch=False,
            )
        return {"case_id": case_id, "created": created, "changes": merged, "error": None}
    except Exception as exc:
        logger.warning("Could not create internet change case for connection %s: %s", connection_id, exc)
        # Keep the import operational, but persist a visible control item whenever
        # the audit table itself is available.
        try:
            execute_query(
                """INSERT INTO internet_connection_change_cases
                   (connection_id,source_type,source_key,source_label,source_url,changes,last_error)
                   VALUES (%s,%s,%s,%s,%s,%s::jsonb,%s)
                   ON CONFLICT (connection_id,source_type,source_key) DO UPDATE
                   SET changes=internet_connection_change_cases.changes || EXCLUDED.changes,
                       last_error=EXCLUDED.last_error, updated_at=NOW()""",
                (connection_id, source_type, source_key, source_label, source_url,
                 json.dumps(relevant, ensure_ascii=False), str(exc)),
                fetch=False,
            )
        except Exception:
            logger.exception("Could not persist failed internet change-case audit")
        return {"case_id": None, "created": False, "changes": relevant, "error": str(exc)}