#!/bin/bash
# BSV Bible Reader - Read the Bible directly from the BSV blockchain
# Works on Linux/Mac with curl and jq installed
#
# Usage: ./read-bible.sh "Genesis" 1
# Usage: ./read-bible.sh "John" 3
# Usage: ./read-bible.sh --list-books
#
# Requirements: curl, jq, xxd
# Install jq: brew install jq (Mac) or apt install jq (Linux)

set -e

# Colors
CYAN='\033[0;36m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
GRAY='\033[0;90m'
NC='\033[0m' # No Color

# Master index transaction ID
MASTER_INDEX_TXID="cf53cae0cf36ffe8333c7ada3416e897ae8ff11d6acc7c1905cabd725a089157"

# Function to fetch transaction from WhatsOnChain
fetch_tx() {
    local txid=$1
    curl -s "https://api.whatsonchain.com/v1/bsv/main/tx/${txid}"
}

# Function to decode OP_RETURN data from transaction
decode_op_return() {
    local tx_json=$1

    # Get the OP_RETURN hex (output with value 0)
    local hex=$(echo "$tx_json" | jq -r '.vout[] | select(.value == 0) | .scriptPubKey.hex')

    if [ -z "$hex" ]; then
        echo "No OP_RETURN found" >&2
        return 1
    fi

    # Parse the script
    local pos=0

    # Skip OP_FALSE (00) if present
    if [ "${hex:$pos:2}" == "00" ]; then
        pos=$((pos + 2))
    fi

    # Skip OP_RETURN (6a)
    if [ "${hex:$pos:2}" == "6a" ]; then
        pos=$((pos + 2))
    fi

    # Skip protocol prefix pushdata (BIBLE1)
    local prefix_push=$((16#${hex:$pos:2}))
    pos=$((pos + 2))

    if [ $prefix_push -le 75 ]; then
        pos=$((pos + prefix_push * 2))
    elif [ $prefix_push -eq 76 ]; then
        local len=$((16#${hex:$pos:2}))
        pos=$((pos + 2 + len * 2))
    fi

    # Read data length pushdata
    local data_push=$((16#${hex:$pos:2}))
    pos=$((pos + 2))

    local data_len=0
    if [ $data_push -le 75 ]; then
        data_len=$data_push
    elif [ $data_push -eq 76 ]; then
        # OP_PUSHDATA1
        data_len=$((16#${hex:$pos:2}))
        pos=$((pos + 2))
    elif [ $data_push -eq 77 ]; then
        # OP_PUSHDATA2 (little-endian)
        local low=$((16#${hex:$pos:2}))
        local high=$((16#${hex:$((pos+2)):2}))
        data_len=$((low + high * 256))
        pos=$((pos + 4))
    elif [ $data_push -eq 78 ]; then
        # OP_PUSHDATA4 (little-endian)
        local b0=$((16#${hex:$pos:2}))
        local b1=$((16#${hex:$((pos+2)):2}))
        local b2=$((16#${hex:$((pos+4)):2}))
        local b3=$((16#${hex:$((pos+6)):2}))
        data_len=$((b0 + b1 * 256 + b2 * 65536 + b3 * 16777216))
        pos=$((pos + 8))
    fi

    # Extract the hex data and decode to UTF-8
    local data_hex=${hex:$pos:$((data_len * 2))}
    echo "$data_hex" | xxd -r -p
}

# Show usage
show_usage() {
    echo -e "${GREEN}=== BSV BIBLE READER ===${NC}"
    echo "Read the King James Bible directly from the BSV blockchain."
    echo ""
    echo -e "${YELLOW}Usage:${NC}"
    echo "  ./read-bible.sh \"Genesis\" 1      # Read Genesis chapter 1"
    echo "  ./read-bible.sh \"John\" 3         # Read John chapter 3"
    echo "  ./read-bible.sh --list-books      # List all books"
    echo "  ./read-bible.sh \"Psalms\" 23 --raw # Output raw JSON"
    echo ""
    echo -e "${CYAN}Source: https://bsvbible.club${NC}"
    echo -e "${GRAY}Master Index TxId: ${MASTER_INDEX_TXID}${NC}"
}

# List available books
list_books() {
    echo -e "\n${GREEN}=== BSV BIBLE - Books Available ===${NC}"
    echo -e "\n${YELLOW}OLD TESTAMENT:${NC}"
    echo "Genesis, Exodus, Leviticus, Numbers, Deuteronomy, Joshua, Judges, Ruth,"
    echo "1 Samuel, 2 Samuel, 1 Kings, 2 Kings, 1 Chronicles, 2 Chronicles,"
    echo "Ezra, Nehemiah, Esther, Job, Psalms, Proverbs, Ecclesiastes,"
    echo "Song of Solomon, Isaiah, Jeremiah, Lamentations, Ezekiel, Daniel,"
    echo "Hosea, Joel, Amos, Obadiah, Jonah, Micah, Nahum, Habakkuk,"
    echo "Zephaniah, Haggai, Zechariah, Malachi"
    echo -e "\n${YELLOW}NEW TESTAMENT:${NC}"
    echo "Matthew, Mark, Luke, John, Acts, Romans, 1 Corinthians, 2 Corinthians,"
    echo "Galatians, Ephesians, Philippians, Colossians, 1 Thessalonians,"
    echo "2 Thessalonians, 1 Timothy, 2 Timothy, Titus, Philemon, Hebrews,"
    echo "James, 1 Peter, 2 Peter, 1 John, 2 John, 3 John, Jude, Revelation"
    echo -e "\n${CYAN}Usage: ./read-bible.sh \"John\" 3${NC}"
}

# Check dependencies
check_deps() {
    for cmd in curl jq xxd; do
        if ! command -v $cmd &> /dev/null; then
            echo "Error: $cmd is required but not installed." >&2
            if [ "$cmd" == "jq" ]; then
                echo "Install with: brew install jq (Mac) or apt install jq (Linux)" >&2
            fi
            exit 1
        fi
    done
}

# Main
check_deps

if [ "$1" == "--list-books" ] || [ "$1" == "-l" ]; then
    list_books
    exit 0
fi

if [ -z "$1" ] || [ -z "$2" ]; then
    show_usage
    exit 0
fi

BOOK=$1
CHAPTER=$2
RAW=false

if [ "$3" == "--raw" ] || [ "$3" == "-r" ]; then
    RAW=true
fi

echo -e "\n${GREEN}=== BSV BIBLE ===${NC}"
echo -e "${CYAN}Fetching chapter index...${NC}"

# Fetch the transaction index
TX_INDEX=$(curl -s "https://bsvbible.club/tx-index.json")

CHAPTER_KEY="${BOOK}_${CHAPTER}"
TXID=$(echo "$TX_INDEX" | jq -r ".\"${CHAPTER_KEY}\"")

if [ "$TXID" == "null" ] || [ -z "$TXID" ]; then
    echo -e "${YELLOW}Chapter not found: ${CHAPTER_KEY}${NC}" >&2
    echo "Use --list-books to see available books" >&2
    exit 1
fi

echo -e "${GREEN}Found: ${CHAPTER_KEY}${NC}"
echo -e "${GRAY}TxId: ${TXID}${NC}"
echo -e "${CYAN}Fetching from blockchain...${NC}"

# Fetch the transaction
TX_JSON=$(fetch_tx "$TXID")

# Decode the OP_RETURN data
DATA=$(decode_op_return "$TX_JSON")

if [ "$RAW" == true ]; then
    echo "$DATA"
    exit 0
fi

# Parse and display
BOOK_NAME=$(echo "$DATA" | jq -r '.book')
CHAPTER_NUM=$(echo "$DATA" | jq -r '.chapter')

echo -e "\n${YELLOW}=== ${BOOK_NAME} Chapter ${CHAPTER_NUM} ===${NC}"
echo -e "${GRAY}Source: BSV Blockchain (immutable)${NC}"
echo -e "${GRAY}Verify: https://whatsonchain.com/tx/${TXID}${NC}\n"

# Display verses
echo "$DATA" | jq -r '.verses | to_entries[] | "\(.key + 1) \(.value)"' | while read -r line; do
    VERSE_NUM=$(echo "$line" | cut -d' ' -f1)
    VERSE_TEXT=$(echo "$line" | cut -d' ' -f2-)
    echo -e "${CYAN}${VERSE_NUM}${NC} ${VERSE_TEXT}"
done

echo -e "\n${GRAY}[End of ${BOOK_NAME} ${CHAPTER_NUM}]${NC}"