from __future__ import annotations

import re
from typing import Any, Dict, List, Tuple

# More restrictive: only [a-z0-9_] to avoid docker/compose surprises
DOCKER_SAFE_RE = re.compile(r"^[a-z0-9_]+$")


def strip_nulls(obj: Any) -> Any:
    """
    Recursively remove keys with None values from dicts and None items from lists.

    This canonicalizes LLM output by removing noise like:
      {"id": null, "io": null, "physical_value": null}
    turning it into:
      {}

    Args:
        obj: Any JSON-serializable object (dict, list, scalar)

    Returns:
        The same structure with None values/items removed
    """
    if isinstance(obj, dict):
        return {k: strip_nulls(v) for k, v in obj.items() if v is not None}
    elif isinstance(obj, list):
        return [strip_nulls(item) for item in obj if item is not None]
    else:
        return obj

def patch_fill_required_keys(cfg: dict[str, Any]) -> Tuple[dict[str, Any], List[str]]:
    """
    Ensure keys that ICS-SimLab setup.py reads with direct indexing exist.
    Prevents KeyError like plc["controllers"] or ui["network"].

    Returns: (patched_cfg, patch_errors)
    """
    patch_errors: List[str] = []

    if not isinstance(cfg, dict):
        return cfg, ["Top-level JSON is not an object"]

    # Top-level defaults
    if "ui" not in cfg or not isinstance(cfg.get("ui"), dict):
        cfg["ui"] = {}

    # ui.network required by setup.py
    ui = cfg["ui"]
    if "network" not in ui or not isinstance(ui.get("network"), dict):
        ui["network"] = {}
    uinet = ui["network"]

    # Ensure port exists (safe default)
    if "port" not in uinet:
        uinet["port"] = 5000

    for k in ["hmis", "plcs", "sensors", "actuators", "hils", "serial_networks", "ip_networks"]:
        if k not in cfg or not isinstance(cfg.get(k), list):
            cfg[k] = []

    def ensure_registers(obj: dict[str, Any]) -> None:
        r = obj.setdefault("registers", {})
        if not isinstance(r, dict):
            obj["registers"] = {}
            r = obj["registers"]
        for kk in ["coil", "discrete_input", "holding_register", "input_register"]:
            if kk not in r or not isinstance(r.get(kk), list):
                r[kk] = []

    def ensure_plc(plc: dict[str, Any]) -> None:
        plc.setdefault("inbound_connections", [])
        plc.setdefault("outbound_connections", [])
        ensure_registers(plc)
        plc.setdefault("monitors", [])
        plc.setdefault("controllers", [])  # critical for setup.py

    def ensure_hmi(hmi: dict[str, Any]) -> None:
        hmi.setdefault("inbound_connections", [])
        hmi.setdefault("outbound_connections", [])
        ensure_registers(hmi)
        hmi.setdefault("monitors", [])
        hmi.setdefault("controllers", [])

    def ensure_sensor(s: dict[str, Any]) -> None:
        s.setdefault("inbound_connections", [])
        ensure_registers(s)

    def ensure_actuator(a: dict[str, Any]) -> None:
        a.setdefault("inbound_connections", [])
        ensure_registers(a)

    for item in cfg.get("plcs", []) or []:
        if isinstance(item, dict):
            ensure_plc(item)
        else:
            patch_errors.append("plcs contains non-object item")

    for item in cfg.get("hmis", []) or []:
        if isinstance(item, dict):
            ensure_hmi(item)
        else:
            patch_errors.append("hmis contains non-object item")

    for item in cfg.get("sensors", []) or []:
        if isinstance(item, dict):
            ensure_sensor(item)
        else:
            patch_errors.append("sensors contains non-object item")

    for item in cfg.get("actuators", []) or []:
        if isinstance(item, dict):
            ensure_actuator(item)
        else:
            patch_errors.append("actuators contains non-object item")

    return cfg, patch_errors


def patch_lowercase_names(cfg: dict[str, Any]) -> Tuple[dict[str, Any], List[str]]:
    """
    Force all device names to lowercase.
    Updates references that depend on device names (sensor/actuator 'hil').

    Returns: (patched_cfg, patch_errors)
    """
    patch_errors: List[str] = []

    if not isinstance(cfg, dict):
        return cfg, ["Top-level JSON is not an object"]

    mapping: Dict[str, str] = {}
    all_names: List[str] = []

    for section in ["hmis", "plcs", "sensors", "actuators", "hils"]:
        for dev in cfg.get(section, []) or []:
            if isinstance(dev, dict) and isinstance(dev.get("name"), str):
                n = dev["name"]
                all_names.append(n)
                mapping[n] = n.lower()

    lowered = [n.lower() for n in all_names]
    collisions = {n for n in set(lowered) if lowered.count(n) > 1}
    if collisions:
        patch_errors.append(f"Lowercase patch would create duplicate device names: {sorted(list(collisions))}")

    # apply
    for section in ["hmis", "plcs", "sensors", "actuators", "hils"]:
        for dev in cfg.get(section, []) or []:
            if isinstance(dev, dict) and isinstance(dev.get("name"), str):
                dev["name"] = dev["name"].lower()

    # update references
    for section in ["sensors", "actuators"]:
        for dev in cfg.get(section, []) or []:
            if not isinstance(dev, dict):
                continue
            h = dev.get("hil")
            if isinstance(h, str):
                dev["hil"] = mapping.get(h, h.lower())

    return cfg, patch_errors


def sanitize_docker_name(name: str) -> str:
    """
    Very safe docker name: [a-z0-9_] only, lowercase.
    """
    s = (name or "").strip().lower()
    s = re.sub(r"\s+", "_", s)        # spaces -> _
    s = re.sub(r"[^a-z0-9_]", "", s)  # keep only [a-z0-9_]
    s = re.sub(r"_+", "_", s)
    s = s.strip("_")
    if not s:
        s = "network"
    if not s[0].isalnum():
        s = "n" + s
    return s


def sanitize_connection_id(name: str) -> str:
    """
    Sanitize outbound_connection id to docker-safe format: [a-z0-9_] only.

    This ensures connection IDs are consistent and safe for use in
    docker container networking and as Python variable names.

    Args:
        name: Original connection id (e.g., "To-Sensor1", "TO_ACTUATOR")

    Returns:
        Sanitized id (e.g., "to_sensor1", "to_actuator")
    """
    s = (name or "").strip().lower()
    s = re.sub(r"\s+", "_", s)        # spaces -> _
    s = re.sub(r"-", "_", s)          # hyphens -> _ (common in connection IDs)
    s = re.sub(r"[^a-z0-9_]", "", s)  # keep only [a-z0-9_]
    s = re.sub(r"_+", "_", s)         # collapse multiple underscores
    s = s.strip("_")
    if not s:
        s = "connection"
    if not s[0].isalnum():
        s = "c" + s
    return s


def patch_sanitize_network_names(cfg: dict[str, Any]) -> Tuple[dict[str, Any], List[str]]:
    """
    Make ip_networks names docker-safe and align ip_networks[].name == ip_networks[].docker_name.
    Update references to docker_network fields.

    Returns: (patched_cfg, patch_errors)
    """
    patch_errors: List[str] = []

    if not isinstance(cfg, dict):
        return cfg, ["Top-level JSON is not an object"]

    dn_map: Dict[str, str] = {}

    for net in cfg.get("ip_networks", []) or []:
        if not isinstance(net, dict):
            continue

        # Ensure docker_name exists
        if not isinstance(net.get("docker_name"), str):
            if isinstance(net.get("name"), str):
                net["docker_name"] = sanitize_docker_name(net["name"])
            else:
                continue

        old_dn = net["docker_name"]
        new_dn = sanitize_docker_name(old_dn)
        dn_map[old_dn] = new_dn
        net["docker_name"] = new_dn

        # force aligned name
        net["name"] = new_dn

    # ui docker_network
    ui = cfg.get("ui")
    if isinstance(ui, dict):
        uinet = ui.get("network")
        if isinstance(uinet, dict):
            dn = uinet.get("docker_network")
            if isinstance(dn, str):
                uinet["docker_network"] = dn_map.get(dn, sanitize_docker_name(dn))

    # device docker_network
    for section in ["hmis", "plcs", "sensors", "actuators"]:
        for dev in cfg.get(section, []) or []:
            if not isinstance(dev, dict):
                continue
            net = dev.get("network")
            if not isinstance(net, dict):
                continue
            dn = net.get("docker_network")
            if isinstance(dn, str):
                net["docker_network"] = dn_map.get(dn, sanitize_docker_name(dn))

    # validate docker-safety
    for net in cfg.get("ip_networks", []) or []:
        if not isinstance(net, dict):
            continue
        dn = net.get("docker_name")
        nm = net.get("name")
        if isinstance(dn, str) and not DOCKER_SAFE_RE.match(dn):
            patch_errors.append(f"ip_networks.docker_name not docker-safe after patch: {dn}")
        if isinstance(nm, str) and not DOCKER_SAFE_RE.match(nm):
            patch_errors.append(f"ip_networks.name not docker-safe after patch: {nm}")

    return cfg, patch_errors


def patch_sanitize_connection_ids(cfg: dict[str, Any]) -> Tuple[dict[str, Any], List[str]]:
    """
    Sanitize all outbound_connection IDs to docker-safe format [a-z0-9_].
    Update all monitor/controller outbound_connection_id references consistently.

    This ensures connection IDs are:
    - Lowercase
    - Only contain [a-z0-9_]
    - Consistent between outbound_connections and monitors/controllers

    Returns: (patched_cfg, patch_errors)
    """
    patch_errors: List[str] = []

    if not isinstance(cfg, dict):
        return cfg, ["Top-level JSON is not an object"]

    # Process PLCs and HMIs (both have outbound_connections, monitors, controllers)
    for section in ["plcs", "hmis"]:
        for dev in cfg.get(section, []) or []:
            if not isinstance(dev, dict):
                continue

            dev_name = dev.get("name", "unknown")

            # Build mapping: old_id -> new_id
            id_map: Dict[str, str] = {}

            # Sanitize outbound_connection IDs
            for conn in dev.get("outbound_connections", []) or []:
                if not isinstance(conn, dict):
                    continue
                old_id = conn.get("id")
                if isinstance(old_id, str) and old_id:
                    new_id = sanitize_connection_id(old_id)
                    if old_id != new_id:
                        id_map[old_id] = new_id
                    conn["id"] = new_id

            # Update monitor outbound_connection_id references
            for monitor in dev.get("monitors", []) or []:
                if not isinstance(monitor, dict):
                    continue
                conn_id = monitor.get("outbound_connection_id")
                if isinstance(conn_id, str):
                    # Use mapped ID if changed, otherwise sanitize directly
                    if conn_id in id_map:
                        monitor["outbound_connection_id"] = id_map[conn_id]
                    else:
                        monitor["outbound_connection_id"] = sanitize_connection_id(conn_id)

            # Update controller outbound_connection_id references
            for controller in dev.get("controllers", []) or []:
                if not isinstance(controller, dict):
                    continue
                conn_id = controller.get("outbound_connection_id")
                if isinstance(conn_id, str):
                    if conn_id in id_map:
                        controller["outbound_connection_id"] = id_map[conn_id]
                    else:
                        controller["outbound_connection_id"] = sanitize_connection_id(conn_id)

    # Validate all connection IDs are docker-safe after patch
    for section in ["plcs", "hmis"]:
        for dev in cfg.get(section, []) or []:
            if not isinstance(dev, dict):
                continue
            dev_name = dev.get("name", "unknown")
            for conn in dev.get("outbound_connections", []) or []:
                if not isinstance(conn, dict):
                    continue
                conn_id = conn.get("id")
                if isinstance(conn_id, str) and not DOCKER_SAFE_RE.match(conn_id):
                    patch_errors.append(
                        f"{section}['{dev_name}'].outbound_connections[].id "
                        f"not docker-safe after patch: {conn_id}"
                    )

    return cfg, patch_errors