"""REST API for fanout config CRUD."""

import logging
import re
import string

from fastapi import APIRouter, HTTPException
from pydantic import BaseModel, Field

from app.config import settings as server_settings
from app.repository.fanout import FanoutConfigRepository

logger = logging.getLogger(__name__)
router = APIRouter(prefix="/fanout", tags=["fanout"])

_VALID_TYPES = {"mqtt_private", "mqtt_community", "bot", "webhook", "apprise"}

_IATA_RE = re.compile(r"^[A-Z]{3}$")
_DEFAULT_COMMUNITY_MQTT_TOPIC_TEMPLATE = "meshcore/{IATA}/{PUBLIC_KEY}/packets"
_DEFAULT_COMMUNITY_MQTT_BROKER_HOST = "mqtt-us-v1.letsmesh.net"
_DEFAULT_COMMUNITY_MQTT_BROKER_PORT = 443
_DEFAULT_COMMUNITY_MQTT_TRANSPORT = "websockets"
_DEFAULT_COMMUNITY_MQTT_AUTH_MODE = "token"
_COMMUNITY_MQTT_TEMPLATE_FIELD_CANONICAL = {
    "iata": "IATA",
    "public_key": "PUBLIC_KEY",
}
_ALLOWED_COMMUNITY_MQTT_TRANSPORTS = {"tcp", "websockets"}
_ALLOWED_COMMUNITY_MQTT_AUTH_MODES = {"token", "password", "none"}


def _normalize_community_topic_template(topic_template: str) -> str:
    """Normalize Community MQTT topic template placeholders to canonical uppercase form."""
    template = topic_template.strip() or _DEFAULT_COMMUNITY_MQTT_TOPIC_TEMPLATE
    parts: list[str] = []
    try:
        parsed = string.Formatter().parse(template)
        for literal_text, field_name, format_spec, conversion in parsed:
            parts.append(literal_text)
            if field_name is None:
                continue
            normalized_field = _COMMUNITY_MQTT_TEMPLATE_FIELD_CANONICAL.get(field_name.lower())
            if normalized_field is None:
                raise HTTPException(
                    status_code=400,
                    detail=(
                        f"topic_template may only use {{IATA}} and {{PUBLIC_KEY}}; got {field_name}"
                    ),
                )
            replacement = ["{", normalized_field]
            if conversion:
                replacement.extend(["!", conversion])
            if format_spec:
                replacement.extend([":", format_spec])
            replacement.append("}")
            parts.append("".join(replacement))
    except ValueError as exc:
        raise HTTPException(status_code=400, detail=f"Invalid topic_template: {exc}") from None

    return "".join(parts)


class FanoutConfigCreate(BaseModel):
    type: str = Field(description="Integration type: 'mqtt_private' or 'mqtt_community'")
    name: str = Field(min_length=1, description="User-assigned label")
    config: dict = Field(default_factory=dict, description="Type-specific config blob")
    scope: dict = Field(default_factory=dict, description="Scope controls")
    enabled: bool = Field(default=True, description="Whether enabled on creation")


class FanoutConfigUpdate(BaseModel):
    name: str | None = Field(default=None, min_length=1, description="Updated label")
    config: dict | None = Field(default=None, description="Updated config blob")
    scope: dict | None = Field(default=None, description="Updated scope controls")
    enabled: bool | None = Field(default=None, description="Enable/disable toggle")


def _validate_mqtt_private_config(config: dict) -> None:
    """Validate mqtt_private config blob."""
    if not config.get("broker_host"):
        raise HTTPException(status_code=400, detail="broker_host is required for mqtt_private")
    port = config.get("broker_port", 1883)
    if not isinstance(port, int) or port < 1 or port > 65535:
        raise HTTPException(status_code=400, detail="broker_port must be between 1 and 65535")


def _validate_mqtt_community_config(config: dict) -> None:
    """Validate mqtt_community config blob. Normalizes IATA to uppercase."""
    broker_host = str(config.get("broker_host", _DEFAULT_COMMUNITY_MQTT_BROKER_HOST)).strip()
    if not broker_host:
        broker_host = _DEFAULT_COMMUNITY_MQTT_BROKER_HOST
    config["broker_host"] = broker_host

    port = config.get("broker_port", _DEFAULT_COMMUNITY_MQTT_BROKER_PORT)
    if not isinstance(port, int) or port < 1 or port > 65535:
        raise HTTPException(status_code=400, detail="broker_port must be between 1 and 65535")
    config["broker_port"] = port

    transport = str(config.get("transport", _DEFAULT_COMMUNITY_MQTT_TRANSPORT)).strip().lower()
    if transport not in _ALLOWED_COMMUNITY_MQTT_TRANSPORTS:
        raise HTTPException(
            status_code=400,
            detail="transport must be 'websockets' or 'tcp'",
        )
    config["transport"] = transport
    config["use_tls"] = bool(config.get("use_tls", True))
    config["tls_verify"] = bool(config.get("tls_verify", True))

    auth_mode = str(config.get("auth_mode", _DEFAULT_COMMUNITY_MQTT_AUTH_MODE)).strip().lower()
    if auth_mode not in _ALLOWED_COMMUNITY_MQTT_AUTH_MODES:
        raise HTTPException(
            status_code=400,
            detail="auth_mode must be 'token', 'password', or 'none'",
        )
    config["auth_mode"] = auth_mode
    username = str(config.get("username", "")).strip()
    password = str(config.get("password", "")).strip()
    if auth_mode == "password" and (not username or not password):
        raise HTTPException(
            status_code=400,
            detail="username and password are required when auth_mode is 'password'",
        )
    config["username"] = username
    config["password"] = password

    token_audience = str(config.get("token_audience", "")).strip()
    config["token_audience"] = token_audience

    iata = config.get("iata", "").upper().strip()
    if not iata or not _IATA_RE.fullmatch(iata):
        raise HTTPException(
            status_code=400,
            detail="IATA code is required and must be exactly 3 uppercase alphabetic characters",
        )
    config["iata"] = iata

    topic_template = str(
        config.get("topic_template", _DEFAULT_COMMUNITY_MQTT_TOPIC_TEMPLATE)
    ).strip()
    if not topic_template:
        topic_template = _DEFAULT_COMMUNITY_MQTT_TOPIC_TEMPLATE

    config["topic_template"] = _normalize_community_topic_template(topic_template)


def _validate_bot_config(config: dict) -> None:
    """Validate bot config blob (syntax-check the code)."""
    code = config.get("code", "")
    if not code or not code.strip():
        raise HTTPException(status_code=400, detail="Bot code cannot be empty")
    try:
        compile(code, "<bot_code>", "exec")
    except SyntaxError as e:
        raise HTTPException(
            status_code=400,
            detail=f"Bot code has syntax error at line {e.lineno}: {e.msg}",
        ) from None


def _validate_apprise_config(config: dict) -> None:
    """Validate apprise config blob."""
    urls = config.get("urls", "")
    if not urls or not urls.strip():
        raise HTTPException(status_code=400, detail="At least one Apprise URL is required")


def _validate_webhook_config(config: dict) -> None:
    """Validate webhook config blob."""
    url = config.get("url", "")
    if not url:
        raise HTTPException(status_code=400, detail="url is required for webhook")
    if not url.startswith(("http://", "https://")):
        raise HTTPException(status_code=400, detail="url must start with http:// or https://")
    method = config.get("method", "POST").upper()
    if method not in ("POST", "PUT", "PATCH"):
        raise HTTPException(status_code=400, detail="method must be POST, PUT, or PATCH")
    headers = config.get("headers", {})
    if not isinstance(headers, dict):
        raise HTTPException(status_code=400, detail="headers must be a JSON object")


def _enforce_scope(config_type: str, scope: dict) -> dict:
    """Enforce type-specific scope constraints. Returns normalized scope."""
    if config_type == "mqtt_community":
        return {"messages": "none", "raw_packets": "all"}
    if config_type == "bot":
        return {"messages": "all", "raw_packets": "none"}
    if config_type in ("webhook", "apprise"):
        messages = scope.get("messages", "all")
        if messages not in ("all", "none") and not isinstance(messages, dict):
            raise HTTPException(
                status_code=400,
                detail="scope.messages must be 'all', 'none', or a filter object",
            )
        return {"messages": messages, "raw_packets": "none"}
    # For mqtt_private, validate scope values
    messages = scope.get("messages", "all")
    if messages not in ("all", "none") and not isinstance(messages, dict):
        raise HTTPException(
            status_code=400,
            detail="scope.messages must be 'all', 'none', or a filter object",
        )
    raw_packets = scope.get("raw_packets", "all")
    if raw_packets not in ("all", "none"):
        raise HTTPException(
            status_code=400,
            detail="scope.raw_packets must be 'all' or 'none'",
        )
    return {"messages": messages, "raw_packets": raw_packets}


@router.get("")
async def list_fanout_configs() -> list[dict]:
    """List all fanout configs."""
    return await FanoutConfigRepository.get_all()


@router.post("")
async def create_fanout_config(body: FanoutConfigCreate) -> dict:
    """Create a new fanout config."""
    if body.type not in _VALID_TYPES:
        raise HTTPException(
            status_code=400,
            detail=f"Invalid type '{body.type}'. Must be one of: {', '.join(sorted(_VALID_TYPES))}",
        )

    if body.type == "bot" and server_settings.disable_bots:
        raise HTTPException(status_code=403, detail="Bot system disabled by server configuration")

    # Only validate config when creating as enabled — disabled configs
    # are drafts the user hasn't finished configuring yet.
    if body.enabled:
        if body.type == "mqtt_private":
            _validate_mqtt_private_config(body.config)
        elif body.type == "mqtt_community":
            _validate_mqtt_community_config(body.config)
        elif body.type == "bot":
            _validate_bot_config(body.config)
        elif body.type == "webhook":
            _validate_webhook_config(body.config)
        elif body.type == "apprise":
            _validate_apprise_config(body.config)

    scope = _enforce_scope(body.type, body.scope)

    cfg = await FanoutConfigRepository.create(
        config_type=body.type,
        name=body.name,
        config=body.config,
        scope=scope,
        enabled=body.enabled,
    )

    # Start the module if enabled
    if cfg["enabled"]:
        from app.fanout.manager import fanout_manager

        await fanout_manager.reload_config(cfg["id"])

    logger.info("Created fanout config %s (type=%s, name=%s)", cfg["id"], body.type, body.name)
    return cfg


@router.patch("/{config_id}")
async def update_fanout_config(config_id: str, body: FanoutConfigUpdate) -> dict:
    """Update a fanout config. Triggers module reload."""
    existing = await FanoutConfigRepository.get(config_id)
    if existing is None:
        raise HTTPException(status_code=404, detail="Fanout config not found")

    if existing["type"] == "bot" and server_settings.disable_bots:
        raise HTTPException(status_code=403, detail="Bot system disabled by server configuration")

    kwargs = {}
    if body.name is not None:
        kwargs["name"] = body.name
    if body.enabled is not None:
        kwargs["enabled"] = body.enabled
    if body.config is not None:
        kwargs["config"] = body.config
    if body.scope is not None:
        kwargs["scope"] = _enforce_scope(existing["type"], body.scope)

    # Validate config when the result will be enabled
    will_be_enabled = body.enabled if body.enabled is not None else existing["enabled"]
    if will_be_enabled:
        config_to_validate = body.config if body.config is not None else existing["config"]
        if existing["type"] == "mqtt_private":
            _validate_mqtt_private_config(config_to_validate)
        elif existing["type"] == "mqtt_community":
            _validate_mqtt_community_config(config_to_validate)
        elif existing["type"] == "bot":
            _validate_bot_config(config_to_validate)
        elif existing["type"] == "webhook":
            _validate_webhook_config(config_to_validate)
        elif existing["type"] == "apprise":
            _validate_apprise_config(config_to_validate)

    updated = await FanoutConfigRepository.update(config_id, **kwargs)
    if updated is None:
        raise HTTPException(status_code=404, detail="Fanout config not found")

    # Reload the module to pick up changes
    from app.fanout.manager import fanout_manager

    await fanout_manager.reload_config(config_id)

    logger.info("Updated fanout config %s", config_id)
    return updated


@router.delete("/{config_id}")
async def delete_fanout_config(config_id: str) -> dict:
    """Delete a fanout config."""
    existing = await FanoutConfigRepository.get(config_id)
    if existing is None:
        raise HTTPException(status_code=404, detail="Fanout config not found")

    # Stop the module first
    from app.fanout.manager import fanout_manager

    await fanout_manager.remove_config(config_id)
    await FanoutConfigRepository.delete(config_id)

    logger.info("Deleted fanout config %s", config_id)
    return {"deleted": True}