package nostr

import (
	"context"
	"encoding/json"
	"time"

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

// Metadata mirrors the kind:0 profile JSON. We accept both snake_case
// (`display_name`, NIP-24) and the deprecated camelCase `displayName` since
// some clients still publish only the latter. `Username` is also deprecated
// but appears in older profiles; per NIP-24 it should be ignored in favor of
// `Name`, but we surface it as a last-resort fallback.
type Metadata struct {
	Name           string `json:"name"`
	DisplayName    string `json:"display_name"`
	DisplayNameAlt string `json:"displayName"`
	Username       string `json:"username"`
	NIP05          string `json:"nip05"`
	About          string `json:"about"`
	Picture        string `json:"picture"`
}

// ParseMetadata decodes a kind:0 content payload.
func ParseMetadata(content string) (*Metadata, error) {
	var md Metadata
	if err := json.Unmarshal([]byte(content), &md); err != nil {
		return nil, err
	}
	return &md, nil
}

// FetchMetadata pulls the most recent kind:0 event for a hex pubkey across the pool.
// Each relay may return multiple replacement events; we keep the one with the
// highest CreatedAt across every relay reached before timeout.
func FetchMetadata(ctx context.Context, p *Pool, hexpk string) (*Metadata, error) {
	filter := gn.Filter{
		Kinds:   []int{0},
		Authors: []string{hexpk},
		Limit:   100,
	}

	var newest *gn.Event
	for _, url := range p.URLs() {
		r, err := p.Connect(ctx, url)
		if err != nil {
			continue
		}
		subCtx, cancel := context.WithTimeout(ctx, 8*time.Second)
		sub, err := r.Subscribe(subCtx, gn.Filters{filter})
		if err != nil {
			cancel()
			continue
		}
	loop:
		for {
			select {
			case ev, ok := <-sub.Events:
				if !ok {
					break loop
				}
				if newest == nil || ev.CreatedAt > newest.CreatedAt {
					newest = ev
				}
			case <-sub.EndOfStoredEvents:
				break loop
			case <-subCtx.Done():
				break loop
			}
		}
		sub.Unsub()
		cancel()
	}

	if newest == nil {
		return nil, nil
	}
	return ParseMetadata(newest.Content)
}