package node

import (
	"fmt"
	"net/http"
	"strings"

	"go-blockchain/blockchain"
	"go-blockchain/wallet"
)

// GET /api/nfts — list all NFTs.
func apiNFTs(q ExplorerQuery) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if q.GetNFTs == nil {
			jsonErr(w, fmt.Errorf("NFT query not available"), 503)
			return
		}
		nfts, err := q.GetNFTs()
		if err != nil {
			jsonErr(w, err, 500)
			return
		}
		if nfts == nil {
			nfts = []blockchain.NFTRecord{}
		}
		jsonOK(w, map[string]any{
			"count": len(nfts),
			"nfts":  nfts,
		})
	}
}

// GET /api/nfts/{id}             — single NFT metadata
// GET /api/nfts/owner/{pubkey}   — NFTs owned by address
func apiNFTByID(q ExplorerQuery) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		path := strings.TrimPrefix(r.URL.Path, "/api/nfts/")
		parts := strings.SplitN(path, "/", 2)

		// /api/nfts/owner/{pubkey}
		if parts[0] == "owner" {
			if len(parts) < 2 || parts[1] == "" {
				jsonErr(w, fmt.Errorf("pubkey required"), 400)
				return
			}
			pubKey := parts[1]
			if strings.HasPrefix(pubKey, "DC") && q.AddressToPubKey != nil {
				if pk, err := q.AddressToPubKey(pubKey); err == nil && pk != "" {
					pubKey = pk
				}
			}
			if q.NFTsByOwner == nil {
				jsonErr(w, fmt.Errorf("NFT query not available"), 503)
				return
			}
			nfts, err := q.NFTsByOwner(pubKey)
			if err != nil {
				jsonErr(w, err, 500)
				return
			}
			if nfts == nil {
				nfts = []blockchain.NFTRecord{}
			}
			jsonOK(w, map[string]any{"count": len(nfts), "nfts": nfts})
			return
		}

		// /api/nfts/{id}
		nftID := parts[0]
		if nftID == "" {
			jsonErr(w, fmt.Errorf("NFT ID required"), 400)
			return
		}
		if q.GetNFT == nil {
			jsonErr(w, fmt.Errorf("NFT query not available"), 503)
			return
		}
		rec, err := q.GetNFT(nftID)
		if err != nil {
			jsonErr(w, err, 500)
			return
		}
		if rec == nil {
			jsonErr(w, fmt.Errorf("NFT %s not found", nftID), 404)
			return
		}
		// Attach owner address for convenience.
		ownerAddr := ""
		if rec.Owner != "" {
			ownerAddr = wallet.PubKeyToAddress(rec.Owner)
		}
		jsonOK(w, map[string]any{
			"nft":          rec,
			"owner_address": ownerAddr,
		})
	}
}

// GET /api/tokens — list all issued tokens.
func apiTokens(q ExplorerQuery) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if q.GetTokens == nil {
			jsonErr(w, fmt.Errorf("token query not available"), 503)
			return
		}
		tokens, err := q.GetTokens()
		if err != nil {
			jsonErr(w, err, 500)
			return
		}
		if tokens == nil {
			tokens = []blockchain.TokenRecord{}
		}
		jsonOK(w, map[string]any{
			"count":  len(tokens),
			"tokens": tokens,
		})
	}
}

// GET /api/tokens/{id}              — token metadata
// GET /api/tokens/{id}/balance/{pub} — token balance for a public key or DC address
func apiTokenByID(q ExplorerQuery) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		path := strings.TrimPrefix(r.URL.Path, "/api/tokens/")
		parts := strings.SplitN(path, "/", 3)

		tokenID := parts[0]
		if tokenID == "" {
			jsonErr(w, fmt.Errorf("token ID required"), 400)
			return
		}

		// /api/tokens/{id}/balance/{pub}
		if len(parts) == 3 && parts[1] == "balance" {
			pubOrAddr := parts[2]
			if pubOrAddr == "" {
				jsonErr(w, fmt.Errorf("pubkey or address required"), 400)
				return
			}
			// Resolve DC address to pubkey if needed.
			pubKey := pubOrAddr
			if strings.HasPrefix(pubOrAddr, "DC") && q.AddressToPubKey != nil {
				if pk, err := q.AddressToPubKey(pubOrAddr); err == nil && pk != "" {
					pubKey = pk
				}
			}
			if q.TokenBalance == nil {
				jsonErr(w, fmt.Errorf("token balance query not available"), 503)
				return
			}
			bal, err := q.TokenBalance(tokenID, pubKey)
			if err != nil {
				jsonErr(w, err, 500)
				return
			}
			jsonOK(w, map[string]any{
				"token_id": tokenID,
				"pub_key":  pubKey,
				"address":  wallet.PubKeyToAddress(pubKey),
				"balance":  bal,
			})
			return
		}

		// /api/tokens/{id}
		if q.GetToken == nil {
			jsonErr(w, fmt.Errorf("token query not available"), 503)
			return
		}
		rec, err := q.GetToken(tokenID)
		if err != nil {
			jsonErr(w, err, 500)
			return
		}
		if rec == nil {
			jsonErr(w, fmt.Errorf("token %s not found", tokenID), 404)
			return
		}
		jsonOK(w, rec)
	}
}