#!/bin/bash
set -e

DUCKDB_PORT="${DUCKDB_PORT:-8432}"
DUCKDB_DATABASE="${DUCKDB_DATABASE:-:memory:}"
DUCKDB_DATA_DIR="${DUCKDB_DATA_DIR:-/data/duckdb}"
DUCKDB_READ_ONLY="${DUCKDB_READ_ONLY:-false}"

# Create query handler script
create_handler() {
    cat > /tmp/duckdb_handler.sh << 'HANDLER'
#!/bin/bash

DUCKDB_DATABASE="${DUCKDB_DATABASE:-:memory:}"
DUCKDB_READ_ONLY="${DUCKDB_READ_ONLY:-false}"

# Read HTTP request
read -r request_line
method=$(echo "$request_line" | cut -d' ' -f1)
path=$(echo "$request_line" | cut -d' ' -f2)

# Read headers
content_length=0
while read -r header; do
    header=$(echo "$header" | tr -d '\r')
    [ -z "$header" ] && break
    if [[ "$header" =~ ^[Cc]ontent-[Ll]ength:\ *([0-9]+) ]]; then
        content_length="${BASH_REMATCH[1]}"
    fi
done

# Read body
body=""
if [ "$content_length" -gt 0 ]; then
    body=$(head -c "$content_length")
fi

# Route request
send_response() {
    local status="$1"
    local content_type="$2"
    local body="$3"
    local body_length=${#body}

    printf "HTTP/1.1 %s\r\n" "$status"
    printf "Content-Type: %s\r\n" "$content_type"
    printf "Content-Length: %d\r\n" "$body_length"
    printf "Connection: close\r\n"
    printf "\r\n"
    printf "%s" "$body"
}

# Health check
if [ "$path" = "/health" ]; then
    send_response "200 OK" "application/json" '{"status":"ok"}'
    exit 0
fi

# Query endpoint
if [ "$path" = "/query" ] && [ "$method" = "POST" ]; then
    # Extract SQL from JSON body
    sql=$(echo "$body" | jq -r '.sql // empty')

    if [ -z "$sql" ]; then
        send_response "400 Bad Request" "application/json" '{"error":"Missing sql field"}'
        exit 0
    fi

    # Build duckdb command
    duckdb_args=()
    if [ "$DUCKDB_READ_ONLY" = "true" ]; then
        duckdb_args+=("-readonly")
    fi
    duckdb_args+=("-json")
    duckdb_args+=("$DUCKDB_DATABASE")

    # Execute query
    start_time=$(date +%s%3N)
    result=$(echo "$sql" | duckdb "${duckdb_args[@]}" 2>&1) || {
        error_msg=$(echo "$result" | jq -Rs '.')
        send_response "400 Bad Request" "application/json" "{\"success\":false,\"error\":$error_msg}"
        exit 0
    }
    end_time=$(date +%s%3N)
    time_ms=$((end_time - start_time))

    # Parse result
    if [ -z "$result" ] || [ "$result" = "[]" ]; then
        send_response "200 OK" "application/json" "{\"success\":true,\"rows\":[],\"row_count\":0,\"time_ms\":$time_ms}"
    else
        row_count=$(echo "$result" | jq 'length')
        columns=$(echo "$result" | jq -c '.[0] | keys')
        rows=$(echo "$result" | jq -c '[.[] | [.[]]]')

        response=$(jq -n \
            --argjson columns "$columns" \
            --argjson rows "$rows" \
            --argjson row_count "$row_count" \
            --argjson time_ms "$time_ms" \
            '{success:true, columns:$columns, rows:$rows, row_count:$row_count, time_ms:$time_ms}')

        send_response "200 OK" "application/json" "$response"
    fi
    exit 0
fi

# Not found
send_response "404 Not Found" "application/json" '{"error":"Not found. Use POST /query"}'
HANDLER

    chmod +x /tmp/duckdb_handler.sh

    # Export env vars for handler
    export DUCKDB_DATABASE
    export DUCKDB_READ_ONLY
}

# Serve HTTP API
serve_api() {
    echo "Starting DuckDB HTTP API on port $DUCKDB_PORT..."
    echo "Database: $DUCKDB_DATABASE"
    echo "Data directory: $DUCKDB_DATA_DIR"
    [ "$DUCKDB_READ_ONLY" = "true" ] && echo "Mode: read-only"

    exec socat TCP-LISTEN:$DUCKDB_PORT,reuseaddr,fork EXEC:"/tmp/duckdb_handler.sh"
}

create_handler
serve_api