import java.util.Properties

/**
 * Injects build-time secrets into `commonMain` so they stay out of version control.
 *
 * Each secret is read from the environment first (CI), then from `local.properties`
 * (local development), and defaults to an empty string when neither provides it —
 * consumers are expected to degrade gracefully rather than fail.
 *
 * The values are emitted as a generated `BuildSecrets` object, available to every
 * Kotlin target of the module.
 */

plugins {
    id("org.jetbrains.kotlin.multiplatform")
}

val secretsPackage = "bzh.ajaury.chombev"

private val localProperties: Provider<Properties> =
    providers
        .fileContents(layout.settingsDirectory.file("local.properties"))
        .asText
        .map { text -> Properties().apply { load(text.reader()) } }

/** Resolves a secret from [environmentVariable], falling back to [localPropertyKey], then to an empty string. */
fun secret(
    environmentVariable: String,
    localPropertyKey: String,
): Provider<String> =
    providers
        .environmentVariable(environmentVariable)
        .orElse(localProperties.map { properties -> properties.getProperty(localPropertyKey).orEmpty() })
        .orElse("")

// GlitchTip DSN, consumed by initializeSentry() in the shared module.
val glitchtipDsn: Provider<String> = secret(environmentVariable = "GLITCHTIP_DSN", localPropertyKey = "glitchtip.dsn")

val generateBuildSecrets =
    tasks.register("generateBuildSecrets") {
        description = "Generates the BuildSecrets object from local.properties and environment variables."

        // Escaped here so the value can be inlined as-is in a Kotlin string literal.
        val dsn =
            glitchtipDsn.map { value ->
                value
                    .replace("\\", "\\\\")
                    .replace("\"", "\\\"")
                    .replace("$", "\${'$'}")
            }
        val outputDir = layout.buildDirectory.dir("generated/secrets/commonMain/kotlin")
        // Kept in locals so the execution-time action never captures the script instance.
        val packageName = secretsPackage
        val packagePath = packageName.replace('.', '/')

        inputs.property("glitchtipDsn", dsn)
        outputs.dir(outputDir)

        doLast {
            val file =
                outputDir
                    .get()
                    .asFile
                    .resolve("$packagePath/BuildSecrets.kt")
            file.parentFile.mkdirs()
            file.writeText(
                """
                package $packageName

                // Generated by the `gwenedeg.secrets` convention plugin. Do not edit.
                internal object BuildSecrets {
                    const val GLITCHTIP_DSN: String = "${dsn.get()}"
                }

                """.trimIndent(),
            )
        }
    }

kotlin {
    sourceSets.commonMain {
        kotlin.srcDir(generateBuildSecrets)
    }
}