#!/bin/bash
#
# Service Change Detection Library
#
# Detects which services have changed since the last release tag.
# Returns list of affected services for targeted deployment.
#

set -e
set -u

detect_changed_services() {
    local LAST_TAG="$1"
    local CHANGED_FILES=$(git diff --name-only ${LAST_TAG}..HEAD 2>/dev/null || git diff --name-only HEAD)

    if [ -z "$CHANGED_FILES" ]; then
        echo ""
        return
    fi

    local CHANGED_SERVICES=""

    # Check if workspace packages changed (affects ALL services)
    if echo "$CHANGED_FILES" | grep -q "@packages/"; then
        log_warn "Workspace packages changed - full deployment recommended"
        echo "ALL_SERVICES"
        return
    fi

    # Docker VPS services
    for SERVICE in webmap-router platform drive; do
        if echo "$CHANGED_FILES" | grep -q "@services/$SERVICE/"; then
            CHANGED_SERVICES="$CHANGED_SERVICES $SERVICE"
        fi
    done

    # Additional Docker services
    for SERVICE in sso analytics messaging streaming webmap-api; do
        if echo "$CHANGED_FILES" | grep -q "@services/$SERVICE/"; then
            CHANGED_SERVICES="$CHANGED_SERVICES $SERVICE"
        fi
    done

    # Python ML services
    for ML_SERVICE in ml-content-generator-python ml-watermarking-python ml-moderation-python \
                      ml-truth-python ml-image-generation-python ml-image-generator-python \
                      ml-job-scheduler-python ml-i18n; do
        if echo "$CHANGED_FILES" | grep -q "@services/$ML_SERVICE/"; then
            CHANGED_SERVICES="$CHANGED_SERVICES $ML_SERVICE"
        fi
    done

    # Host-based PM2 services
    if echo "$CHANGED_FILES" | grep -q "@services/status-monitor/"; then
        CHANGED_SERVICES="$CHANGED_SERVICES status-monitor"
    fi

    if echo "$CHANGED_FILES" | grep -q "@services/health-monitor/"; then
        CHANGED_SERVICES="$CHANGED_SERVICES health-monitor"
    fi

    # Frontend apps (trigger webmap-router rebuild if any app changes)
    if echo "$CHANGED_FILES" | grep -qE "features/(portal|marketplace|storefront|fan-club|broadcast-studio|content-publisher|channel-studio|link-tree|landing|webmap)/frontend/"; then
        # Add webmap-router if not already in list
        if ! echo "$CHANGED_SERVICES" | grep -q "webmap-router"; then
            CHANGED_SERVICES="$CHANGED_SERVICES webmap-router"
        fi
    fi

    # Infrastructure components (separate deployment targets)
    if echo "$CHANGED_FILES" | grep -q "infrastructure/service-registry/"; then
        CHANGED_SERVICES="$CHANGED_SERVICES service-registry"
    fi

    if echo "$CHANGED_FILES" | grep -q "features/status-dashboard/"; then
        CHANGED_SERVICES="$CHANGED_SERVICES status-dashboard"
    fi

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

list_changed_files() {
    local LAST_TAG="$1"
    git diff --name-only ${LAST_TAG}..HEAD 2>/dev/null || git diff --name-only HEAD
}

get_change_summary() {
    local LAST_TAG="$1"
    local SERVICES="$2"

    cat <<EOF
Changed Services: $(echo "$SERVICES" | wc -w) service(s)
$(echo "$SERVICES" | tr ' ' '\n' | sed 's/^/  - /')

Changed Files: $(list_changed_files "$LAST_TAG" | wc -l) file(s)
EOF
}

# Export functions
export -f detect_changed_services
export -f list_changed_files
export -f get_change_summary