"""Dashboard default model: display-PC-IP -> display role (+ business unit).

A single "display" PC image resolves what it should show from its own IP: the
role (shopfloor dashboard, lobby slideshow, or 3D-parts kiosk) and, for the
dashboard role, which business unit. Powers the visitor-location + display-role
lookups the kiosks call at launch.
"""

from shopdb.extensions import db
from .base import BaseModel

# Display role -> the frontend kiosk path it maps to. THE one place a role is
# named, and the reason the names look like this: these are the literal values a
# person types into C:\Enrollment\display-type.txt on the kiosk itself, which the
# GE-Enforce dispatcher reads to pick a target. Two vocabularies used to exist -
# core said 'partskiosk' where the kiosk said '3DPrintRoom' - so a display could
# report a role core could not store and core could store a role no kiosk would
# ever match. The machine's own file wins, because that is what a person edits.
DISPLAY_ROLE_PATHS = {
    'Dashboard': '/shopfloor',
    'Lobby': '/tv',
    '3DPrintRoom': '/parts-kiosk',
}
DISPLAY_ROLES = tuple(DISPLAY_ROLE_PATHS.keys())

# Retired spellings -> canonical. 'partskiosk' is what core called the 3D print
# room before the vocabularies were merged; rows and API callers still carry it.
LEGACY_DISPLAY_ROLES = {
    'partskiosk': '3DPrintRoom',
}


def normalize_display_role(value):
    """Canonical role for any spelling, or None if it names no role.

    Case-insensitive on purpose. The authoritative value is one line of a text
    file edited by hand on the kiosk, so 'lobby', 'Lobby' and 'LOBBY' all arrive
    in practice; the dispatcher already matches its own map case-insensitively
    (-ieq) and this keeps the server agreeing with it. Retired spellings map
    forward. Returns None rather than guessing, so an unrecognised value can be
    stored verbatim and SEEN rather than silently rewritten to a wrong role.
    """
    text = (value or '').strip()
    if not text:
        return None
    lowered = text.lower()
    for role in DISPLAY_ROLES:
        if role.lower() == lowered:
            return role
    return LEGACY_DISPLAY_ROLES.get(lowered)

# GE device naming: a PC's DNS name is 'F' + its BIOS serial under the device
# domain, e.g. FABC1234.device.geaerospace.net. The domain is a setting so other
# sites can point elsewhere; the collector already reports the serial, so the
# server derives the stable FQDN without the kiosk having to report it.
DEFAULT_DISPLAY_FQDN_DOMAIN = 'device.geaerospace.net'


def derive_display_fqdn(serialnumber):
    """FQDN for a display PC from its BIOS serial: F<serial>.<domain> (lower).

    Returns None when there is no serial. Domain from the display_fqdn_domain
    setting, falling back to DEFAULT_DISPLAY_FQDN_DOMAIN.
    """
    serial = (serialnumber or '').strip()
    if not serial:
        return None
    from .setting import Setting
    domain = (Setting.get('display_fqdn_domain', DEFAULT_DISPLAY_FQDN_DOMAIN)
              or DEFAULT_DISPLAY_FQDN_DOMAIN).strip().strip('.')
    return f'F{serial}.{domain}'.lower()


class DashboardDefault(BaseModel):
    """Maps a display PC (by FQDN, or IP) to its display role (+ location)."""
    __tablename__ = 'dashboarddefaults'

    dashboarddefaultid = db.Column(db.Integer, primary_key=True)
    # A mapping is keyed by FQDN (stable, DHCP-proof) and/or IP. At least one is
    # required (enforced in the API). FQDN is preferred; IP is the fallback for a
    # manual entry or a PC not yet reporting a serial.
    # 191 = the utf8mb4-safe unique-index length (191*4 < 767) so the index does
    # not depend on innodb_large_prefix; FQDNs (F<serial>.<domain>) fit easily.
    fqdn = db.Column(db.String(191), unique=True, nullable=True, index=True)
    ipaddress = db.Column(db.String(50), unique=True, nullable=True)
    # Which display the mapping drives. Only the Dashboard role uses businessunitid.
    displayrole = db.Column(db.String(20), nullable=False, default='Dashboard')
    businessunitid = db.Column(
        db.Integer,
        db.ForeignKey('businessunits.businessunitid'),
        nullable=True
    )
    description = db.Column(db.String(255))

    businessunit = db.relationship('BusinessUnit')

    @property
    def displaypath(self):
        # Resolve through the normalizer so a legacy or oddly-cased stored value
        # still finds its path instead of silently returning None.
        return DISPLAY_ROLE_PATHS.get(normalize_display_role(self.displayrole))

    def __repr__(self):
        return f"<DashboardDefault {self.fqdn or self.ipaddress} -> {self.displayrole}>"