#!/bin/bash
# Usage: CHAIN_DATA_URL=https://gist.githubusercontent.com/samcm/e2da294dab77e93ad0ee0e815580294f/raw/da79a6bd82f6d07e8caca11beb27bdab8b29a7d3/holesky-lighthouse-erigon.json BEACON_NODE_URL=http://localhost:5052 ./check.sh

# Default CHAIN_DATA_URL if not provided
CHAIN_DATA_URL=${CHAIN_DATA_URL:-"https://gist.githubusercontent.com/samcm/e2da294dab77e93ad0ee0e815580294f/raw/da79a6bd82f6d07e8caca11beb27bdab8b29a7d3/holesky-lighthouse-erigon.json"}
# Default BEACON_NODE_URL if not provided
BEACON_NODE_URL=${BEACON_NODE_URL:-"http://localhost:5052"}

echo "CHAIN_DATA_URL: $CHAIN_DATA_URL"
echo "BEACON_NODE_URL: $BEACON_NODE_URL"

# Download chain data
CHAIN_DATA=$(curl -s "$CHAIN_DATA_URL")
if [ $? -ne 0 ]; then
    echo "❌ Failed to download chain data from $CHAIN_DATA_URL"
    exit 1
fi

# Get highest slot from chain data
HIGHEST_SLOT=$(echo "$CHAIN_DATA" | jq -r 'keys | map(tonumber) | max')
if [ -z "$HIGHEST_SLOT" ] || [ "$HIGHEST_SLOT" = "null" ]; then
    echo "❌ No slots found in chain data"
    exit 1
fi

# Calculate highest epoch
HIGHEST_EPOCH=$((HIGHEST_SLOT / 32))
echo "🔍 Checking slots starting from $HIGHEST_SLOT (epoch $HIGHEST_EPOCH)..."

# Get all slots in descending order
SLOTS=$(echo "$CHAIN_DATA" | jq -r 'keys | map(tonumber) | sort | reverse | .[]')

# Track if we found a match
FOUND_MATCH=false
# Track if we found a fork
FOUND_FORK=false
# Track the fork point
FORK_SLOT=""
FORK_EPOCH=""
FORK_EXPECTED_ROOT=""
FORK_NODE_ROOT=""

for SLOT in $SLOTS; do
    # Calculate epoch for this slot
    CURRENT_EPOCH=$((SLOT / 32))
    
    # Get expected root for this slot
    EXPECTED_ROOT=$(echo "$CHAIN_DATA" | jq -r --arg SLOT "$SLOT" '.[$SLOT]')
    
    # Try to get the block at this slot from the beacon node
    NODE_DATA=$(curl -s "$BEACON_NODE_URL/eth/v1/beacon/headers/$SLOT")
    STATUS=$?
    
    # Check if request was successful
    if [ $STATUS -eq 0 ] && [ "$(echo "$NODE_DATA" | jq 'has("data")')" = "true" ]; then
        # Extract root from node
        NODE_ROOT=$(echo "$NODE_DATA" | jq -r '.data.root')
        
        # Compare roots
        if [ "$NODE_ROOT" = "$EXPECTED_ROOT" ]; then
            echo "✅ Matching root at slot $SLOT (epoch $CURRENT_EPOCH): $NODE_ROOT"
            FOUND_MATCH=true
            
            # If we previously found a fork, this is where the chains converge again
            if [ "$FOUND_FORK" = true ]; then
                echo "🔀 Chains converge at slot $SLOT (epoch $CURRENT_EPOCH)"
                break
            else
                # If we haven't found a fork and found a match, we're on the right chain
                break
            fi
        else
            # We found a fork
            if [ "$FOUND_FORK" = false ]; then
                # This is the first fork point we found
                FOUND_FORK=true
                FORK_SLOT=$SLOT
                FORK_EPOCH=$CURRENT_EPOCH
                FORK_EXPECTED_ROOT=$EXPECTED_ROOT
                FORK_NODE_ROOT=$NODE_ROOT
                
                echo "❌ Fork detected at slot $SLOT (epoch $CURRENT_EPOCH)!"
                echo "  Expected root: $EXPECTED_ROOT"
                echo "  Node's root:   $NODE_ROOT"
                echo "🔍 Continuing to search for fork point..."
            fi
        fi
    else
        echo "⏭️  Slot $SLOT (epoch $CURRENT_EPOCH) not found on node, trying earlier slot..."
    fi
done

# Final status report
if [ "$FOUND_MATCH" = true ]; then
    if [ "$FOUND_FORK" = true ]; then
        echo "🔀 Node is on a different fork that diverged at slot $FORK_SLOT (epoch $FORK_EPOCH)"
        echo "  Expected root: $FORK_EXPECTED_ROOT"
        echo "  Node's root:   $FORK_NODE_ROOT"
        exit 1
    else
        echo "✅ Node is on the correct fork"
        exit 0
    fi
elif [ "$FOUND_FORK" = true ]; then
    echo "❌ Node is on a different fork, and no common ancestor was found"
    echo "  Fork detected at slot $FORK_SLOT (epoch $FORK_EPOCH)"
    exit 1
else
    echo "❌ None of the slots in chain data were found on the node"
    exit 1
fi