package nostr

import (
	"fmt"

	"github.com/nbd-wtf/go-nostr"
	"github.com/nbd-wtf/go-nostr/nip19"
)

// Naddr represents a parsed naddr (Nostr addressable event reference)
type Naddr struct {
	Kind     int
	Pubkey   string
	DTag     string
	Relays   []string
	RawNaddr string
}

// ParseNaddr decodes a bech32-encoded naddr string and extracts its components
// Uses the go-nostr library's nip19.Decode which supports longer naddr strings
func ParseNaddr(naddr string) (*Naddr, error) {
	// Use go-nostr's nip19.Decode which handles longer strings via DecodeNoLimit
	prefix, value, err := nip19.Decode(naddr)
	if err != nil {
		return nil, fmt.Errorf("failed to decode naddr: %w", err)
	}

	if prefix != "naddr" {
		return nil, fmt.Errorf("invalid naddr prefix: expected 'naddr', got '%s'", prefix)
	}

	// Cast to EntityPointer
	ep, ok := value.(nostr.EntityPointer)
	if !ok {
		return nil, fmt.Errorf("failed to parse naddr: unexpected type")
	}

	if ep.Kind == 0 {
		return nil, fmt.Errorf("naddr missing kind")
	}
	if ep.PublicKey == "" {
		return nil, fmt.Errorf("naddr missing pubkey")
	}
	if ep.Identifier == "" {
		return nil, fmt.Errorf("naddr missing d tag")
	}

	return &Naddr{
		Kind:     ep.Kind,
		Pubkey:   ep.PublicKey,
		DTag:     ep.Identifier,
		Relays:   ep.Relays,
		RawNaddr: naddr,
	}, nil
}

// ToEventReference converts the naddr to an event reference string (kind:pubkey:d)
func (n *Naddr) ToEventReference() string {
	return fmt.Sprintf("%d:%s:%s", n.Kind, n.Pubkey, n.DTag)
}

// ToFilter creates a nostr filter for this naddr
func (n *Naddr) ToFilter() nostr.Filter {
	return nostr.Filter{
		Kinds:   []int{n.Kind},
		Authors: []string{n.Pubkey},
		Tags: map[string][]string{
			"d": {n.DTag},
		},
	}
}

// CreateNaddr creates a bech32-encoded naddr from kind, pubkey, dtag, and optional relays
func CreateNaddr(kind int, pubkey string, dtag string, relays []string) (string, error) {
	// nip19.EncodeEntity signature: (publicKey string, kind int, identifier string, relays []string)
	naddr, err := nip19.EncodeEntity(pubkey, kind, dtag, relays)
	if err != nil {
		return "", fmt.Errorf("failed to encode naddr: %w", err)
	}

	return naddr, nil
}