package db

import (
	"net/netip"
	"strings"
	"vppn/hub/errs"
)

func Config_Sanitize(c *Config) {
}

func Config_Validate(c *Config) error {
	return nil
}

func Network_Sanitize(n *Network) {
	n.LocalDomain = strings.TrimSpace(n.LocalDomain)

	if addr, ok := netip.AddrFromSlice(n.Network); ok {
		n.Network = addr.AsSlice()
	}
}

func Network_Validate(c *Network) error {
	// 15 bytes is linux limit for network interface names. With ending .local,
	// max length is 21.
	if len(c.LocalDomain) == 0 || len(c.LocalDomain) > 21 {
		return errs.ErrInvalidNetName
	}

	if !strings.HasSuffix(c.LocalDomain, ".local") {
		return errs.ErrNetNameNotLocal
	}

	for _, c := range strings.TrimSuffix(c.LocalDomain, ".local") {
		if c >= 'a' && c <= 'z' {
			continue
		}
		if c >= '0' && c <= '9' {
			continue
		}
		return errs.ErrInvalidNetName
	}

	addr, ok := netip.AddrFromSlice(c.Network)
	if !ok || !addr.Is4() || addr.As4()[3] != 0 || addr.As4()[0] == 0 {
		return errs.ErrInvalidIP
	}

	if !addr.IsPrivate() {
		return errs.ErrNonPrivateIP
	}

	return nil
}

func Peer_Sanitize(p *Peer) {
	p.Name = strings.TrimSpace(p.Name)
	if len(p.Addr4) != 0 {
		if addr, ok := netip.AddrFromSlice(p.Addr4); ok {
			// Unmap so an IPv4-mapped form is stored canonically as 4 bytes.
			p.Addr4 = addr.Unmap().AsSlice()
		}
	}
	if len(p.Addr6) != 0 {
		if addr, ok := netip.AddrFromSlice(p.Addr6); ok {
			p.Addr6 = addr.AsSlice()
		}
	}
	if p.Port == 0 {
		p.Port = 51820
	}
}

func Peer_Validate(p *Peer) error {
	if p.PeerIP < 1 || p.PeerIP > 254 {
		return errs.ErrInvalidPeerIP
	}
	if len(p.Addr4) > 0 {
		// Must be a genuine IPv4 address (reject an IPv6 in the v4 field).
		if addr, ok := netip.AddrFromSlice(p.Addr4); !ok || !addr.Is4() {
			return errs.ErrInvalidIP
		}
	}
	if len(p.Addr6) > 0 {
		// Must be a genuine IPv6 address (reject IPv4 / IPv4-mapped in the v6 field).
		if addr, ok := netip.AddrFromSlice(p.Addr6); !ok || !addr.Is6() || addr.Is4In6() {
			return errs.ErrInvalidIP
		}
	}
	if p.Port == 0 {
		return errs.ErrInvalidPort
	}

	if len(p.Name) == 0 {
		return errs.ErrInvalidPeerName
	}
	for _, c := range p.Name {
		if c >= 'a' && c <= 'z' {
			continue
		}
		if c >= '0' && c <= '9' {
			continue
		}
		if c == '-' {
			continue
		}
		return errs.ErrInvalidPeerName
	}

	return nil
}