feat(tools): block ETA (#3829)

I used this tool to predict the arrival time of the v2 activation height
on Mocha.

tools/blocketa/README.md

@@ -0,0 +1,18 @@
+# Block ETA (Estimated Time of Arrival)
+
+blocketa is a tool that estimates the time of arrival of a block height.
+
+## Usage
+
+```shell
+$ go run main.go https://celestia-mocha-rpc.publicnode.com:443 2585031
+chainID: mocha-4
+currentHeight: 2580660
+currentTime: 2024-08-28 02:46:32.933542677 +0000 UTC
+diffInBlockHeight: 4371
+diffInTime: 14h37m50.55s
+arrivalTime: 2024-08-28 17:24:23.483542677 +0000 UTC
+```
+
+> [!NOTE]
+> The block time is currently hard-coded. If you're running this for a network with a different block time, you'll need to update the `blockTime` constant in the main.go file. You can use https://www.mintscan.io/celestia/block/ or the blocktime tool.

tools/blocketa/main.go

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+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"strconv"
+	"time"
+
+	"github.com/tendermint/tendermint/rpc/client/http"
+)
+
+const (
+	// blockTime is the observed average time between blocks. You can update this
+	// value based on the block time on https://www.mintscan.io/celestia/block/ or
+	// the output from the blocktime tool.
+	blockTime = 12.05 // seconds between blocks for Mocha
+
+	// exampleArabicaRPC is an example node RPC endpoint for the Arabica testnet.
+	exampleArabicaRPC = "https://rpc.celestia-arabica-11.com:443"
+
+	// exampleMochaRPC is an example node RPC endpoint for the Mocha testnet.
+	exampleMochaRPC = "https://celestia-mocha-rpc.publicnode.com:443"
+
+	// exampleArabicaHeight is an example block height for the Arabica testnet.
+	exampleArabicaHeight = 1751707
+
+	// exampleMochaHeight is an example block height for the Mocha testnet.
+	exampleMochaHeight = 2585031
+)
+
+func main() {
+	if err := Run(); err != nil {
+		fmt.Printf("ERROR: %s", err.Error())
+	}
+}
+
+func Run() error {
+	if len(os.Args) < 3 {
+		fmt.Printf("Usage: %s <node_rpc> <target_block_height>\n", os.Args[0])
+		fmt.Printf("Example: %s %s %v\n", os.Args[0], exampleArabicaRPC, exampleArabicaHeight)
+		fmt.Printf("Example: %s %s %v\n", os.Args[0], exampleMochaRPC, exampleMochaHeight)
+		return nil
+	}
+
+	_, nodeRPC, targetBlockHeightArg := os.Args[0], os.Args[1], os.Args[2]
+	targetBlockHeight, err := strconv.ParseInt(targetBlockHeightArg, 10, 64)
+	if err != nil {
+		return err
+	}
+	c, err := http.New(nodeRPC, "/websocket")
+	if err != nil {
+		return err
+	}
+	resp, err := c.Status(context.Background())
+	if err != nil {
+		return err
+	}
+	chainID := resp.NodeInfo.Network
+	currentHeight := resp.SyncInfo.LatestBlockHeight
+	currentTime := resp.SyncInfo.LatestBlockTime
+
+	if currentHeight >= targetBlockHeight {
+		return fmt.Errorf("current height %v is already after target height %v", currentHeight, targetBlockHeight)
+	}
+	diffInBlockHeight := targetBlockHeight - currentHeight
+	diffInSeconds := blockTime * float64(diffInBlockHeight)
+	diffInTime, err := time.ParseDuration(fmt.Sprintf("%vs", diffInSeconds))
+	if err != nil {
+		return err
+	}
+	arrivalTime := currentTime.Add(diffInTime)
+
+	fmt.Printf("chainID: %v\n", chainID)
+	fmt.Printf("currentHeight: %v\n", currentHeight)
+	fmt.Printf("currentTime: %v\n", currentTime.String())
+	fmt.Printf("diffInBlockHeight: %v\n", diffInBlockHeight)
+	fmt.Printf("diffInTime: %v\n", diffInTime)
+	fmt.Printf("arrivalTime: %v\n", arrivalTime)
+	return nil
+}