import io
import zipfile
from datetime import datetime, timezone
from app import models


class ShorewallGenerator:
    def __init__(self, config: models.Config) -> None:
        self._config = config
        self._ts = datetime.now(timezone.utc).strftime("%Y-%m-%dT%H:%M:%SZ")

    def _header(self, filename: str) -> str:
        return (
            f"# {filename} — generated by shorefront "
            f"| config: {self._config.name} "
            f"| {self._ts}\n"
        )

    def _col(self, *values: str, width: int = 16) -> str:
        return "".join(v.ljust(width) for v in values).rstrip() + "\n"

    def zones(self) -> str:
        lines = [self._header("zones"), "#ZONE".ljust(16) + "TYPE".ljust(16) + "OPTIONS\n"]
        for z in self._config.zones:
            lines.append(self._col(z.name, z.type, z.options or "-"))
        return "".join(lines)

    def interfaces(self) -> str:
        lines = [self._header("interfaces"), "#ZONE".ljust(16) + "INTERFACE".ljust(16) + "BROADCAST".ljust(16) + "OPTIONS\n"]
        for iface in self._config.interfaces:
            zone = iface.zone.name if iface.zone else "-"
            lines.append(self._col(zone, iface.name, iface.broadcast or "-", iface.options or "-"))
        return "".join(lines)

    def policy(self) -> str:
        lines = [
            self._header("policy"),
            "#SOURCE".ljust(16) + "DEST".ljust(16) + "POLICY".ljust(16)
            + "LOG LEVEL".ljust(16) + "LIMIT:BURST".ljust(20) + "CONNLIMIT:MASK\n",
        ]
        for p in sorted(self._config.policies, key=lambda x: x.position):
            src = p.src_zone.name if p.src_zone else "all"
            dst = p.dst_zone.name if p.dst_zone else "all"
            lines.append(self._col(
                src, dst, p.policy,
                p.log_level or "-",
                p.limit_burst or "-",
                p.connlimit_mask or "-",
                width=16,
            ))
        return "".join(lines)

    def rules(self) -> str:
        lines = [
            self._header("rules"),
            "#ACTION".ljust(16) + "SOURCE".ljust(24) + "DEST".ljust(24)
            + "PROTO".ljust(10) + "DPORT".ljust(16) + "SPORT".ljust(16)
            + "ORIGDEST".ljust(20) + "RATE".ljust(16) + "USER".ljust(16)
            + "MARK".ljust(12) + "CONNLIMIT".ljust(14) + "TIME".ljust(20)
            + "HEADERS".ljust(16) + "SWITCH".ljust(16) + "HELPER\n",
            "SECTION NEW\n",
        ]
        for r in sorted(self._config.rules, key=lambda x: x.position):
            src = (r.src_zone.name if r.src_zone else "all") + (f":{r.src_ip}" if r.src_ip else "")
            dst = (r.dst_zone.name if r.dst_zone else "all") + (f":{r.dst_ip}" if r.dst_ip else "")
            lines.append(self._col(
                r.action, src, dst,
                r.proto or "-", r.dport or "-", r.sport or "-",
                r.origdest or "-", r.rate_limit or "-", r.user_group or "-",
                r.mark or "-", r.connlimit or "-", r.time or "-",
                r.headers or "-", r.switch_name or "-", r.helper or "-",
                width=16,
            ))
        return "".join(lines)

    def hosts(self) -> str:
        lines = [self._header("hosts"), "#ZONE".ljust(16) + "HOSTS\n"]
        for h in self._config.host_entries:
            hosts_val = f"{h.interface}:{h.subnet}"
            lines.append(self._col(h.zone.name, hosts_val, h.options or "-", width=16))
        return "".join(lines)

    def params(self) -> str:
        lines = [self._header("params")]
        for p in self._config.params:
            lines.append(f"{p.name}={p.value}\n")
        return "".join(lines)

    def snat(self) -> str:
        lines = [
            self._header("snat"),
            "#ACTION".ljust(24) + "SOURCE".ljust(24) + "DEST".ljust(20)
            + "PROTO".ljust(10) + "PORT".ljust(16) + "IPSEC".ljust(16)
            + "MARK".ljust(12) + "USER/GROUP".ljust(16) + "SWITCH".ljust(16)
            + "ORIGDEST".ljust(20) + "PROBABILITY\n",
        ]
        for m in self._config.snat_entries:
            action = f"SNAT:{m.to_address}" if m.to_address else "MASQUERADE"
            lines.append(self._col(
                action, m.source_network, m.out_interface,
                m.proto or "-", m.port or "-", m.ipsec or "-",
                m.mark or "-", m.user_group or "-", m.switch_name or "-",
                m.origdest or "-", m.probability or "-",
                width=16,
            ))
        return "".join(lines)

    def as_json(self) -> dict:
        return {
            "zones": self.zones(),
            "interfaces": self.interfaces(),
            "policy": self.policy(),
            "rules": self.rules(),
            "snat": self.snat(),
            "hosts": self.hosts(),
            "params": self.params(),
        }

    def as_zip(self) -> bytes:
        buf = io.BytesIO()
        with zipfile.ZipFile(buf, "w", zipfile.ZIP_DEFLATED) as zf:
            zf.writestr("zones", self.zones())
            zf.writestr("interfaces", self.interfaces())
            zf.writestr("policy", self.policy())
            zf.writestr("rules", self.rules())
            zf.writestr("snat", self.snat())
            zf.writestr("hosts", self.hosts())
            zf.writestr("params", self.params())
        return buf.getvalue()