package hub

import (
	"errors"
	"fmt"
	"net"

	"github.com/ghodss/yaml"

	"github.com/safing/jess/lhash"
	"github.com/safing/portmaster/service/profile/endpoints"
)

// Intel holds a collection of various security related data collections on Hubs.
type Intel struct {
	// BootstrapHubs is list of transports that also contain an IP and the Hub's ID.
	BootstrapHubs []string

	// Hubs holds intel regarding specific Hubs.
	Hubs map[string]*HubIntel

	// AdviseOnlyTrustedHubs advises to only use trusted Hubs regardless of intended purpose.
	AdviseOnlyTrustedHubs bool
	// AdviseOnlyTrustedHomeHubs advises to only use trusted Hubs for Home Hubs.
	AdviseOnlyTrustedHomeHubs bool
	// AdviseOnlyTrustedDestinationHubs advises to only use trusted Hubs for Destination Hubs.
	AdviseOnlyTrustedDestinationHubs bool

	// Hub Advisories advise on the usage of Hubs and take the form of Endpoint Lists that match on both IPv4 and IPv6 addresses and their related data.

	// HubAdvisory always affects all Hubs.
	HubAdvisory []string
	// HomeHubAdvisory is only taken into account when selecting a Home Hub.
	HomeHubAdvisory []string
	// DestinationHubAdvisory is only taken into account when selecting a Destination Hub.
	DestinationHubAdvisory []string

	// Regions defines regions to assist network optimization.
	Regions []*RegionConfig

	// VirtualNetworks holds network configurations for virtual cloud networks.
	VirtualNetworks []*VirtualNetworkConfig

	parsed *ParsedIntel
}

// HubIntel holds Hub-related data.
type HubIntel struct { //nolint:golint
	// Trusted specifies if the Hub is specially designated for more sensitive tasks, such as handling unencrypted traffic.
	Trusted bool

	// Discontinued specifies if the Hub has been discontinued and should be marked as offline and removed.
	Discontinued bool

	// VerifiedOwner holds the name of the verified owner / operator of the Hub.
	VerifiedOwner string

	// Override is used to override certain Hub information.
	Override *InfoOverride
}

// RegionConfig holds the configuration of a region.
type RegionConfig struct {
	// ID is the internal identifier of the region.
	ID string
	// Name is a human readable name of the region.
	Name string
	// MemberPolicy specifies a list for including members.
	MemberPolicy []string

	// RegionalMinLanes specifies how many lanes other regions should build
	// to this region.
	RegionalMinLanes int
	// RegionalMinLanesPerHub specifies how many lanes other regions should
	// build to this region, per Hub in this region.
	// This value will usually be below one.
	RegionalMinLanesPerHub float64
	// RegionalMaxLanesOnHub specifies how many lanes from or to another region may be
	// built on one Hub per region.
	RegionalMaxLanesOnHub int

	// SatelliteMinLanes specifies how many lanes satellites (Hubs without
	// region) should build to this region.
	SatelliteMinLanes int
	// SatelliteMinLanesPerHub specifies how many lanes satellites (Hubs without
	// region) should build to this region, per Hub in this region.
	// This value will usually be below one.
	SatelliteMinLanesPerHub float64

	// InternalMinLanesOnHub specifies how many lanes every Hub should create
	// within the region at minimum.
	InternalMinLanesOnHub int
	// InternalMaxHops specifies the max hop constraint for internally optimizing
	// the region.
	InternalMaxHops int
}

// VirtualNetworkConfig holds configuration of a virtual network that binds multiple Hubs together.
type VirtualNetworkConfig struct {
	// Name is a human readable name of the virtual network.
	Name string
	// Force forces the use of the mapped IP addresses after the Hub's IPs have been verified.
	Force bool
	// Mapping maps Hub IDs to internal IP addresses.
	Mapping map[string]net.IP
}

// ParsedIntel holds a collection of parsed intel data.
type ParsedIntel struct {
	// HubAdvisory always affects all Hubs.
	HubAdvisory endpoints.Endpoints

	// HomeHubAdvisory is only taken into account when selecting a Home Hub.
	HomeHubAdvisory endpoints.Endpoints

	// DestinationHubAdvisory is only taken into account when selecting a Destination Hub.
	DestinationHubAdvisory endpoints.Endpoints
}

// Parsed returns the collection of parsed intel data.
func (i *Intel) Parsed() *ParsedIntel {
	return i.parsed
}

// ParseIntel parses Hub intelligence data.
func ParseIntel(data []byte) (*Intel, error) {
	// Load data into struct.
	intel := &Intel{}
	err := yaml.Unmarshal(data, intel)
	if err != nil {
		return nil, fmt.Errorf("failed to parse data: %w", err)
	}

	// Parse all endpoint lists.
	err = intel.ParseAdvisories()
	if err != nil {
		return nil, err
	}

	return intel, nil
}

// ParseAdvisories parses all advisory endpoint lists.
func (i *Intel) ParseAdvisories() (err error) {
	i.parsed = &ParsedIntel{}

	i.parsed.HubAdvisory, err = endpoints.ParseEndpoints(i.HubAdvisory)
	if err != nil {
		return fmt.Errorf("failed to parse HubAdvisory list: %w", err)
	}

	i.parsed.HomeHubAdvisory, err = endpoints.ParseEndpoints(i.HomeHubAdvisory)
	if err != nil {
		return fmt.Errorf("failed to parse HomeHubAdvisory list: %w", err)
	}

	i.parsed.DestinationHubAdvisory, err = endpoints.ParseEndpoints(i.DestinationHubAdvisory)
	if err != nil {
		return fmt.Errorf("failed to parse DestinationHubAdvisory list: %w", err)
	}

	return nil
}

// ParseBootstrapHub parses a bootstrap hub.
func ParseBootstrapHub(bootstrapTransport string) (t *Transport, hubID string, hubIP net.IP, err error) {
	// Parse transport and check Hub ID.
	t, err = ParseTransport(bootstrapTransport)
	if err != nil {
		return nil, "", nil, fmt.Errorf("failed to parse transport: %w", err)
	}
	if t.Option == "" {
		return nil, "", nil, errors.New("missing hub ID in URL fragment")
	}
	if _, err := lhash.FromBase58(t.Option); err != nil {
		return nil, "", nil, fmt.Errorf("hub ID is invalid: %w", err)
	}

	// Parse IP address from transport.
	ip := net.ParseIP(t.Domain)
	if ip == nil {
		return nil, "", nil, errors.New("invalid IP address (domains are not supported for bootstrapping)")
	}

	// Clean up transport for hub info.
	id := t.Option
	t.Domain = ""
	t.Option = ""

	return t, id, ip, nil
}