#!/bin/bash

set -e

SCRIPT_DIR=$(dirname "$0")
cd "$SCRIPT_DIR"

function info() {
    echo "INFO: $1" >&2
}

function get_last_version_tag() {
    # Get the most recent tag that modified versions.json
    git tag --sort=-version:refname | while read tag; do
        if git diff --name-only "$tag" HEAD 2>/dev/null | grep -q "^versions.json$"; then
            echo "$tag"
            return
        fi
    done
    
    # If no tag found, use the initial commit
    echo ""
}

function detect_changed_templates() {
    local base_ref="$1"
    local changed_templates=""
    
    if [ -z "$base_ref" ]; then
        info "No previous version tag found, considering all templates as changed"
        # Return all template directories
        find . -maxdepth 1 -type d ! -name ".*" ! -name "." | sed 's|^\./||' | grep -v ".gitea" | sort
    else
        info "Comparing against $base_ref"
        
        # Get list of changed files since the base ref
        local changed_files=$(git diff --name-only "$base_ref" HEAD 2>/dev/null || echo "")
        
        if [ -z "$changed_files" ]; then
            info "No changes detected since $base_ref"
            return
        fi
        
        # Check which templates have changes
        for template_dir in $(find . -maxdepth 1 -type d ! -name ".*" ! -name "." | sed 's|^\./||' | grep -v ".gitea"); do
            if echo "$changed_files" | grep -q "^${template_dir}/"; then
                echo "$template_dir"
            fi
        done | sort | uniq
    fi
}

# Main execution
if [ "$1" == "--json" ]; then
    # Output as JSON array
    last_tag=$(get_last_version_tag)
    changed=$(detect_changed_templates "$last_tag")
    
    if [ -z "$changed" ]; then
        echo "[]"
    else
        echo -n "["
        first=true
        for template in $changed; do
            if [ "$first" = true ]; then
                first=false
            else
                echo -n ","
            fi
            echo -n "\"$template\""
        done
        echo "]"
    fi
else
    # Output as newline-separated list
    last_tag=$(get_last_version_tag)
    detect_changed_templates "$last_tag"
fi