TemplateManager.kt

package com.hexagontk.templates

import com.hexagontk.core.Platform
import com.hexagontk.core.localized
import java.net.URL
import java.time.LocalDateTime
import java.util.Locale

/**
 * The TemplateManager handles multiple templates adapters.
 */
object TemplateManager {

    var adapters: Map<Regex, TemplatePort> = emptyMap()

    /**
     * Render a template with a registered template engine.
     *
     * @param url Location of the template.
     * @param context Data to use when the template is processed.
     * @param locale Locale used to process the template. If not passed, system's locale is used.
     *
     * @throws IllegalStateException Thrown when no engine for URL was found.
     */
    fun render(url: URL, context: Map<String, *>, locale: Locale = Platform.locale): String {
        val now = LocalDateTime.now()
        val defaultProperties = mapOf("_template_" to url, "_now_" to now)
        return findAdapter(url.localized(locale)).render(url, context + defaultProperties, locale)
    }

    private fun findAdapter(url: URL): TemplatePort =
        adapters
            .filter { it.key.matches(url.toString()) }
            .firstNotNullOfOrNull { it.value  }
            ?: error("No adapter found for resource: $url")
}