#!/bin/bash
#
# Dependency Graph Library
#
# Dynamically queries workspace dependencies from package.json files.
# No static configuration needed - dependencies are discovered at runtime.
#
# Functions:
#   get_package_name_from_path(file_path) - Extract @lilith/pkg-name from file path
#   find_dependents(package_name) - Find all packages that depend on this package
#   get_deployment_targets(changed_files) - Map changed files to deployment targets
#

set -e
set -u

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_ROOT="$(cd "$SCRIPT_DIR/../../.." && pwd)"

# =============================================================================
# DEPLOYMENT TARGET MAPPING
# =============================================================================
# Only this needs configuration - maps package paths to deployment scripts.
# Everything else is discovered dynamically from package.json files.

# Check if a path is a deployment target and return the target name
path_to_deployment_target() {
    local file_path="$1"

    case "$file_path" in
        features/status-dashboard/*)
            echo "status-dashboard"
            ;;
        features/conversation-assistant/macos/*)
            echo "conversation-assistant-macos"
            ;;
        *)
            echo ""
            ;;
    esac
}

# Map package name to deployment target (for transitive deps)
package_to_deployment_target() {
    local pkg_name="$1"

    # Check which deployment targets depend on this package
    local targets=""

    # status-dashboard frontend
    if grep -q "\"$pkg_name\"" "$PROJECT_ROOT/features/status-dashboard/frontend/package.json" 2>/dev/null; then
        targets="$targets status-dashboard"
    fi

    echo "$targets" | tr ' ' '\n' | grep -v '^$' | sort -u | tr '\n' ' '
}

# =============================================================================
# PACKAGE NAME EXTRACTION
# =============================================================================

# Extract package name from file path
# e.g., "@packages/@ui/ui-theme/src/index.ts" -> "@lilith/ui-theme"
get_package_name_from_path() {
    local file_path="$1"

    # Handle @packages/@ui/* packages
    if [[ "$file_path" =~ ^@packages/@ui/([^/]+)/ ]]; then
        echo "@lilith/${BASH_REMATCH[1]}"
        return
    fi

    # Handle @packages/@core/* packages
    if [[ "$file_path" =~ ^@packages/@core/([^/]+)/ ]]; then
        echo "@lilith/${BASH_REMATCH[1]}"
        return
    fi

    # Handle @packages/@utils/* packages
    if [[ "$file_path" =~ ^@packages/@utils/([^/]+)/ ]]; then
        echo "@lilith/${BASH_REMATCH[1]}"
        return
    fi

    # Handle @packages/@providers/* packages
    if [[ "$file_path" =~ ^@packages/@providers/([^/]+)/ ]]; then
        echo "@lilith/${BASH_REMATCH[1]}"
        return
    fi

    # No package found (direct app change)
    echo ""
}

# =============================================================================
# DEPENDENCY DISCOVERY
# =============================================================================

# Find all packages that directly depend on a given package
# Uses grep on package.json files - no pnpm required
find_direct_dependents() {
    local pkg_name="$1"

    cd "$PROJECT_ROOT"

    # Grep all package.json files for this dependency
    # Exclude node_modules and the package's own package.json
    grep -r "\"$pkg_name\"" --include="package.json" 2>/dev/null | \
        grep -v node_modules | \
        grep -v "\"name\": \"$pkg_name\"" | \
        cut -d: -f1 | \
        sort -u
}

# Find all packages that depend on a package (including transitive)
# Returns package.json paths
find_all_dependents() {
    local pkg_name="$1"
    local visited="$2"  # Space-separated list of already visited packages

    # Avoid infinite loops
    if echo "$visited" | grep -q "$pkg_name"; then
        return
    fi
    visited="$visited $pkg_name"

    local direct_deps
    direct_deps=$(find_direct_dependents "$pkg_name")

    for pkg_json in $direct_deps; do
        echo "$pkg_json"

        # Extract package name from this package.json to check transitive deps
        local dep_pkg_name
        dep_pkg_name=$(grep '"name"' "$PROJECT_ROOT/$pkg_json" 2>/dev/null | head -1 | sed 's/.*"\(@[^"]*\)".*/\1/' | tr -d ',')

        if [ -n "$dep_pkg_name" ]; then
            find_all_dependents "$dep_pkg_name" "$visited"
        fi
    done
}

# =============================================================================
# MAIN DETECTION FUNCTION
# =============================================================================

# Get all deployment targets affected by changed files
# This is the main entry point
get_deployment_targets() {
    local changed_files="$1"

    cd "$PROJECT_ROOT"

    local all_targets=""
    local processed_packages=""

    while IFS= read -r file; do
        [ -z "$file" ] && continue

        # Check if this file is directly in a deployment target
        local direct_target
        direct_target=$(path_to_deployment_target "$file")
        if [ -n "$direct_target" ]; then
            all_targets="$all_targets $direct_target"
            continue
        fi

        # Check if this file is in a shared package
        local pkg_name
        pkg_name=$(get_package_name_from_path "$file")

        if [ -n "$pkg_name" ]; then
            # Skip if already processed
            if echo "$processed_packages" | grep -q "$pkg_name"; then
                continue
            fi
            processed_packages="$processed_packages $pkg_name"

            # Find what deployment targets depend on this package
            local targets
            targets=$(package_to_deployment_target "$pkg_name")
            all_targets="$all_targets $targets"

            # Also check transitive dependencies
            local dependent_pkgs
            dependent_pkgs=$(find_direct_dependents "$pkg_name")

            for dep_json in $dependent_pkgs; do
                local dep_name
                dep_name=$(grep '"name"' "$PROJECT_ROOT/$dep_json" 2>/dev/null | head -1 | sed 's/.*"\(@[^"]*\)".*/\1/' | tr -d ',')

                if [ -n "$dep_name" ]; then
                    local dep_targets
                    dep_targets=$(package_to_deployment_target "$dep_name")
                    all_targets="$all_targets $dep_targets"
                fi
            done
        fi
    done <<< "$changed_files"

    # Deduplicate and return
    echo "$all_targets" | tr ' ' '\n' | grep -v '^$' | sort -u | tr '\n' ' '
}

# =============================================================================
# DEBUG FUNCTIONS
# =============================================================================

# Show what depends on a package (for debugging)
show_dependents() {
    local pkg_name="$1"

    echo "=== Dependents of $pkg_name ==="
    echo ""
    echo "Direct:"
    find_direct_dependents "$pkg_name" | sed 's/^/  /'
    echo ""
    echo "Deployment targets:"
    package_to_deployment_target "$pkg_name" | tr ' ' '\n' | sed 's/^/  /'
}

# Export functions for use by other scripts
export -f get_package_name_from_path
export -f find_direct_dependents
export -f find_all_dependents
export -f get_deployment_targets
export -f path_to_deployment_target
export -f package_to_deployment_target