package com.condado.newsletter.service

import com.fasterxml.jackson.annotation.JsonIgnoreProperties
import com.fasterxml.jackson.annotation.JsonProperty
import org.springframework.beans.factory.annotation.Value
import org.springframework.stereotype.Service
import org.springframework.web.client.RestClient

/** Calls a local Llama/Ollama endpoint to generate test task messages. */
@Service
class LlamaPreviewService(
    private val restClient: RestClient,
    @Value("\${llama.base-url:http://localhost:11434}") private val baseUrl: String,
    @Value("\${llama.model:gemma3:4b}") private val model: String
) {

    /**
     * Generates one message from the provided prompt.
     */
    fun generate(prompt: String): String {
        val response = restClient.post()
            .uri("${baseUrl.trimEnd('/')}/api/generate")
            .body(LlamaGenerateRequest(model = model, prompt = prompt, stream = false))
            .retrieve()
            .body(LlamaGenerateResponse::class.java)
            ?: throw IllegalStateException("Llama returned an empty response")

        val text = response.response?.trim().orEmpty()
        if (text.isBlank()) {
            throw IllegalStateException("Llama returned an empty message")
        }

        return text
    }

    private data class LlamaGenerateRequest(
        val model: String,
        val prompt: String,
        val stream: Boolean
    )

    @JsonIgnoreProperties(ignoreUnknown = true)
    private data class LlamaGenerateResponse(
        @JsonProperty("response")
        val response: String?
    )
}