#!/bin/bash
# tin sheet create - Create/register new sheet

set -euo pipefail

# Get tinsnip root and source libraries
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
TINSNIP_ROOT="$(dirname "$(dirname "$SCRIPT_DIR")")"
source "$TINSNIP_ROOT/lib/core.sh"
source "$TINSNIP_ROOT/lib/registry.sh"

# Register a new sheet (interactive)
register_sheet_interactive() {
    local sheet="$1"
    
    log_with_prefix "Sheet Registration" "Registering sheet: $sheet"
    echo
    
    # Check if topsheet.station-prod is available
    if ! check_tinsnip_station; then
        error_with_prefix "Sheet Registration" "Cannot register sheets without topsheet.station-prod"
    fi
    
    # Check if sheet already registered
    if get_sheet_from_registry "$sheet" >/dev/null 2>&1; then
        local existing_number=$(get_sheet_from_registry "$sheet")
        log_with_prefix "Sheet Registration" "Sheet '$sheet' already registered with number $existing_number"
        return 0
    fi
    
    # Find next available number
    local next_number
    if ! next_number=$(find_next_sheet_number); then
        error_with_prefix "Sheet Registration" "No available sheet numbers (range 1-4 full)"
    fi
    
    log_with_prefix "Sheet Registration" "Assigning sheet number: $next_number"

    # Register the sheet
    register_sheet_in_registry "$sheet" "$next_number"

    # Create initial machine registry directory and file for this sheet
    local machine_registry_dir="/mnt/station-prod/data/machines/$sheet"
    local machine_registry="$machine_registry_dir/registry"

    # Create directory if it doesn't exist
    if [[ ! -d "$machine_registry_dir" ]]; then
        sudo -u station-prod mkdir -p "$machine_registry_dir"
    fi

    # Create registry file if it doesn't exist
    if [[ ! -f "$machine_registry" ]]; then
        cat << EOF | sudo -u station-prod tee "$machine_registry" > /dev/null
# Machine Registry for sheet: $sheet
# Format: machine_name=machine_number
# Machine numbers are 2-digit (00-99) and used in UID calculation
EOF
        log_with_prefix "Sheet Registration" "Created machine registry for sheet"
    fi

    echo
    log_with_prefix "Sheet Registration" "✅ Sheet '$sheet' registered successfully"

    # Show current sheets
    echo
    echo "Registered sheets:"
    list_sheets | while IFS='=' read -r name number; do
        echo "  $name = $number"
    done

    echo
    log_with_prefix "Next Steps" "Create machines on this sheet:"
    echo "  TIN_SHEET=$sheet tin machine create <machine> <env> <nas-server>"
}

show_help() {
    cat << EOF
tin sheet create - Create/register new sheet

USAGE:
    tin sheet create <name>
    tin sheet <name>          # Shorthand

DESCRIPTION:
    Register a new sheet for isolating machines. Each sheet gets a unique
    number and separate storage paths. Sheets enable multi-tenant deployments.

ARGUMENTS:
    <name>     Sheet name (lowercase alphanumeric with hyphens and dots)

EXAMPLES:
    tin sheet create infrastructure       # Register 'infrastructure' sheet
    tin sheet mycompany.com              # Register domain-based sheet
    tin sheet mycompany                  # Shorthand to register 'mycompany'

NOTES:
    - Sheet names can include domain names (e.g., example.com)
    - Allowed characters: lowercase letters, numbers, hyphens, dots
    - Sheet 'topsheet' is reserved for platform services
    - Each sheet gets a unique number (1-4) for UID/port allocation

EOF
}

# Main execution
if [[ $# -eq 0 ]]; then
    error_with_prefix "Sheet Create" "Sheet name required"
    echo "Usage: tin sheet create <name>" >&2
    exit 1
fi

# Handle help flags
case "${1:-}" in
    --help|-h|help)
        show_help
        exit 0
        ;;
esac

sheet="$1"

# Reject flags as sheet names
if [[ "$sheet" =~ ^-- ]]; then
    error_with_prefix "Sheet Create" "Sheet name cannot start with '--' (looks like a flag)"
    echo "Usage: tin sheet create <name>" >&2
    exit 1
fi

# Validate sheet name (lowercase alphanumeric with hyphens and dots for domain names)
if [[ ! "$sheet" =~ ^[a-z0-9.-]+$ ]]; then
    error_with_prefix "Sheet Create" "Sheet name must be lowercase alphanumeric with hyphens and dots only"
fi

# Cannot register topsheet (reserved)
if [[ "$sheet" == "topsheet" ]]; then
    error_with_prefix "Sheet Create" "Cannot register 'topsheet' - reserved for platform services"
fi

register_sheet_interactive "$sheet"