#!/bin/bash
#
# Get FoundryVTT download URL using account credentials
# Based on felddy/foundryvtt-docker authentication flow
#
# Usage: get_foundry_download.sh [--url-only] [--version VERSION]
#
# Required environment variables:
#   FOUNDRY_USERNAME - FoundryVTT account username/email
#   FOUNDRY_PASSWORD - FoundryVTT account password
#

set -euo pipefail

# Configuration
FOUNDRY_BASE_URL="https://foundryvtt.com"

# Check required environment variables
if [[ -z "${FOUNDRY_USERNAME:-}" || -z "${FOUNDRY_PASSWORD:-}" ]]; then
    echo "Error: FOUNDRY_USERNAME and FOUNDRY_PASSWORD environment variables are required" >&2
    exit 1
fi

# Create temp file for cookies
COOKIE_JAR=$(mktemp)
trap "rm -f $COOKIE_JAR" EXIT

# Step 1: Get CSRF token from the main page (not login page)
get_csrf_token() {
    local main_page
    main_page=$(curl -fsSL -c "$COOKIE_JAR" -b "$COOKIE_JAR" \
        -H "DNT: 1" \
        -H "Referer: ${FOUNDRY_BASE_URL}" \
        -H "User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36" \
        "${FOUNDRY_BASE_URL}" 2>/dev/null)
    
    # Extract csrfmiddlewaretoken from the form
    local csrf_token
    csrf_token=$(echo "$main_page" | grep -oP 'name="csrfmiddlewaretoken" value="\K[^"]+' 2>/dev/null | head -1)
    
    echo "$csrf_token"
}

# Step 2: Authenticate
authenticate() {
    local csrf_token="$1"
    
    # POST to login
    curl -fsSL -b "$COOKIE_JAR" -c "$COOKIE_JAR" \
        -X POST "${FOUNDRY_BASE_URL}/auth/login/" \
        -H "DNT: 1" \
        -H "Referer: ${FOUNDRY_BASE_URL}" \
        -H "User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36" \
        -H "Content-Type: application/x-www-form-urlencoded" \
        -d "csrfmiddlewaretoken=${csrf_token}&username=${FOUNDRY_USERNAME}&password=${FOUNDRY_PASSWORD}&next=/" \
        -o /dev/null 2>/dev/null || true
    
    # Check for sessionid cookie (indicates successful login)
    if grep -q "sessionid" "$COOKIE_JAR" 2>/dev/null; then
        return 0
    else
        return 1
    fi
}

# Step 3: Get download URL
get_download_url() {
    local version="$1"
    
    # Extract build number from version (e.g., "13.351" -> "351")
    local build
    build="${version##*.}"
    
    # Fetch presigned URL from API
    local response
    response=$(curl -fsSL -b "$COOKIE_JAR" \
        -H "DNT: 1" \
        -H "Referer: ${FOUNDRY_BASE_URL}" \
        -H "User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36" \
        "${FOUNDRY_BASE_URL}/releases/download?build=${build}&platform=node&response_type=json" 2>/dev/null)
    
    # Extract URL from JSON response
    local download_url
    download_url=$(echo "$response" | grep -oP '"url":\s*"\K[^"]+' 2>/dev/null || true)
    
    echo "$download_url"
}

# Main execution
main() {
    local url_only=false
    local version_override=""
    
    # Parse arguments
    while [[ $# -gt 0 ]]; do
        case "$1" in
            --url-only)
                url_only=true
                shift
                ;;
            --version)
                version_override="$2"
                shift 2
                ;;
            *)
                echo "Unknown option: $1" >&2
                exit 1
                ;;
        esac
    done
    
    # Get version
    local version="${version_override:-}"
    if [[ -z "$version" ]]; then
        # Get latest stable version
        version=$(bash "$(dirname "$0")/get_foundry_version.sh" --version-only 2>/dev/null || echo "")
        if [[ -z "$version" ]]; then
            echo "Error: Could not determine FoundryVTT version" >&2
            exit 1
        fi
    fi
    
    if [[ "$url_only" != true ]]; then
        echo "Authenticating with FoundryVTT..." >&2
    fi
    
    local csrf_token
    csrf_token=$(get_csrf_token)
    
    if [[ -z "$csrf_token" ]]; then
        echo "Error: Could not get CSRF token from FoundryVTT" >&2
        exit 1
    fi
    
    if ! authenticate "$csrf_token"; then
        echo "Error: Authentication failed. Check your credentials." >&2
        exit 1
    fi
    
    if [[ "$url_only" != true ]]; then
        echo "Fetching download URL for version ${version}..." >&2
    fi
    
    local download_url
    download_url=$(get_download_url "$version")
    
    if [[ -z "$download_url" || "$download_url" == "null" ]]; then
        echo "Error: Could not retrieve download URL. Make sure you have a valid license." >&2
        exit 1
    fi
    
    echo "$download_url"
}

main "$@"