use crate::http::context::{AppContext, OpenApiResult, bad_request};
use crate::io::fs;
use crate::llm::chat;
use poem_openapi::{Object, OpenApi, Tags, param::Query, payload::Json};
use serde::Deserialize;
use std::sync::Arc;

#[derive(Tags)]
enum ModelTags {
    Model,
}

#[derive(Deserialize, Object)]
struct ModelPayload {
    model: String,
}

pub struct ModelApi {
    pub ctx: Arc<AppContext>,
}

#[OpenApi(tag = "ModelTags::Model")]
impl ModelApi {
    /// Get the currently selected model preference, if any.
    #[oai(path = "/model", method = "get")]
    async fn get_model_preference(&self) -> OpenApiResult<Json<Option<String>>> {
        let result = fs::get_model_preference(self.ctx.store.as_ref()).map_err(bad_request)?;
        Ok(Json(result))
    }

    /// Persist the selected model preference.
    #[oai(path = "/model", method = "post")]
    async fn set_model_preference(&self, payload: Json<ModelPayload>) -> OpenApiResult<Json<bool>> {
        fs::set_model_preference(payload.0.model, self.ctx.store.as_ref()).map_err(bad_request)?;
        Ok(Json(true))
    }

    /// Fetch available model names from an Ollama server.
    /// Optionally override the base URL via query string.
    /// Returns an empty list when Ollama is unreachable so the UI stays functional.
    #[oai(path = "/ollama/models", method = "get")]
    async fn get_ollama_models(
        &self,
        base_url: Query<Option<String>>,
    ) -> OpenApiResult<Json<Vec<String>>> {
        let models = chat::get_ollama_models(base_url.0)
            .await
            .unwrap_or_default();
        Ok(Json(models))
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::http::context::AppContext;
    use tempfile::TempDir;

    fn make_api(dir: &TempDir) -> ModelApi {
        ModelApi {
            ctx: Arc::new(AppContext::new_test(dir.path().to_path_buf())),
        }
    }

    #[tokio::test]
    async fn get_model_preference_returns_none_when_unset() {
        let dir = TempDir::new().unwrap();
        let api = make_api(&dir);
        let result = api.get_model_preference().await.unwrap();
        assert!(result.0.is_none());
    }

    #[tokio::test]
    async fn set_model_preference_returns_true() {
        let dir = TempDir::new().unwrap();
        let api = make_api(&dir);
        let payload = Json(ModelPayload {
            model: "claude-3-sonnet".to_string(),
        });
        let result = api.set_model_preference(payload).await.unwrap();
        assert!(result.0);
    }

    #[tokio::test]
    async fn get_model_preference_returns_value_after_set() {
        let dir = TempDir::new().unwrap();
        let api = make_api(&dir);

        let payload = Json(ModelPayload {
            model: "claude-3-sonnet".to_string(),
        });
        api.set_model_preference(payload).await.unwrap();

        let result = api.get_model_preference().await.unwrap();
        assert_eq!(result.0, Some("claude-3-sonnet".to_string()));
    }

    #[tokio::test]
    async fn set_model_preference_overwrites_previous_value() {
        let dir = TempDir::new().unwrap();
        let api = make_api(&dir);

        api.set_model_preference(Json(ModelPayload {
            model: "model-a".to_string(),
        }))
        .await
        .unwrap();

        api.set_model_preference(Json(ModelPayload {
            model: "model-b".to_string(),
        }))
        .await
        .unwrap();

        let result = api.get_model_preference().await.unwrap();
        assert_eq!(result.0, Some("model-b".to_string()));
    }

    #[tokio::test]
    async fn get_ollama_models_returns_empty_list_for_unreachable_url() {
        let dir = TempDir::new().unwrap();
        let api = make_api(&dir);
        // Port 1 is reserved and should immediately refuse the connection.
        let base_url = Query(Some("http://127.0.0.1:1".to_string()));
        let result = api.get_ollama_models(base_url).await;
        assert!(result.is_ok());
        assert_eq!(result.unwrap().0, Vec::<String>::new());
    }
}