use serde_json::json;
use wiremock::matchers::{method, path};
use wiremock::{Mock, MockServer, ResponseTemplate};

use chat::providers::ollama::OllamaProvider;

// ── helpers ──────────────────────────────────────────────────────────────────

async fn setup() -> (MockServer, OllamaProvider) {
    let server = MockServer::start().await;
    let provider = OllamaProvider::new(server.uri());
    (server, provider)
}

fn models_response(names: &[&str]) -> serde_json::Value {
    json!({
        "models": names.iter().map(|n| json!({ "name": n })).collect::<Vec<_>>()
    })
}

// ── list_models ───────────────────────────────────────────────────────────────

#[tokio::test]
async fn test_list_models_ok() {
    let (server, provider) = setup().await;

    Mock::given(method("GET"))
        .and(path("/api/tags"))
        .respond_with(ResponseTemplate::new(200).set_body_json(models_response(&["llama3"])))
        .mount(&server)
        .await;

    let res = provider.list_models().await.unwrap();
    assert_eq!(res["models"][0]["name"], "llama3");
}

// ── completions ───────────────────────────────────────────────────────────────

#[tokio::test]
async fn test_completions_ok() {
    let (server, provider) = setup().await;

    Mock::given(method("GET"))
        .and(path("/api/tags"))
        .respond_with(ResponseTemplate::new(200).set_body_json(models_response(&["llama3"])))
        .mount(&server)
        .await;

    Mock::given(method("POST"))
        .and(path("/api/generate"))
        .respond_with(ResponseTemplate::new(200).set_body_json(json!({
            "model":            "llama3",
            "response":         "I am a helpful assistant.",
            "done":             true,
            "prompt_eval_count": 10,
            "eval_count":        8,
        })))
        .mount(&server)
        .await;

    let res = provider
        .completions(json!({
            "model":  "llama3",
            "prompt": "Who are you?"
        }))
        .await
        .unwrap();

    assert_eq!(res["object"], "text_completion");
    assert_eq!(res["choices"][0]["text"], "I am a helpful assistant.");
    assert_eq!(res["choices"][0]["finish_reason"], "stop");
    assert_eq!(res["usage"]["prompt_tokens"], 10);
    assert_eq!(res["usage"]["completion_tokens"], 8);
}

#[tokio::test]
async fn test_completions_missing_prompt() {
    let (server, provider) = setup().await;

    Mock::given(method("GET"))
        .and(path("/api/tags"))
        .respond_with(ResponseTemplate::new(200).set_body_json(models_response(&["llama3"])))
        .mount(&server)
        .await;

    let err = provider
        .completions(json!({ "model": "llama3" }))
        .await
        .unwrap_err();
    assert!(matches!(err, chat::errors::OllamaError::MissingPrompt));
}

#[tokio::test]
async fn test_completions_empty_prompt() {
    let (server, provider) = setup().await;

    Mock::given(method("GET"))
        .and(path("/api/tags"))
        .respond_with(ResponseTemplate::new(200).set_body_json(models_response(&["llama3"])))
        .mount(&server)
        .await;

    let err = provider
        .completions(json!({
            "model": "llama3", "prompt": "   "
        }))
        .await
        .unwrap_err();
    assert!(matches!(err, chat::errors::OllamaError::MissingPrompt));
}

#[tokio::test]
async fn test_completions_model_not_found() {
    let (server, provider) = setup().await;

    Mock::given(method("GET"))
        .and(path("/api/tags"))
        .respond_with(ResponseTemplate::new(200).set_body_json(models_response(&["llama3"])))
        .mount(&server)
        .await;

    let err = provider
        .completions(json!({
            "model": "gpt-4", "prompt": "hello"
        }))
        .await
        .unwrap_err();
    assert!(matches!(err, chat::errors::OllamaError::ModelNotFound(_)));
}

// ── chat_completions ──────────────────────────────────────────────────────────

#[tokio::test]
async fn test_chat_completions_ok() {
    let (server, provider) = setup().await;

    Mock::given(method("GET"))
        .and(path("/api/tags"))
        .respond_with(ResponseTemplate::new(200).set_body_json(models_response(&["llama3"])))
        .mount(&server)
        .await;

    Mock::given(method("POST"))
        .and(path("/api/chat"))
        .respond_with(ResponseTemplate::new(200).set_body_json(json!({
            "model": "llama3",
            "message": { "role": "assistant", "content": "4." },
            "done": true,
            "done_reason": "stop",
            "prompt_eval_count": 5,
            "eval_count": 2,
        })))
        .mount(&server)
        .await;

    let res = provider
        .chat_completions(json!({
            "model": "llama3",
            "messages": [
                { "role": "user", "content": "What is 2+2?" }
            ]
        }))
        .await
        .unwrap();

    assert_eq!(res["object"], "chat.completion");
    assert_eq!(res["choices"][0]["message"]["role"], "assistant");
    assert_eq!(res["choices"][0]["message"]["content"], "4.");
    assert_eq!(res["choices"][0]["finish_reason"], "stop");
    assert_eq!(res["usage"]["total_tokens"], 7);
}

#[tokio::test]
async fn test_chat_completions_missing_messages() {
    let (server, provider) = setup().await;

    Mock::given(method("GET"))
        .and(path("/api/tags"))
        .respond_with(ResponseTemplate::new(200).set_body_json(models_response(&["llama3"])))
        .mount(&server)
        .await;

    let err = provider
        .chat_completions(json!({
            "model": "llama3", "messages": []
        }))
        .await
        .unwrap_err();
    assert!(matches!(err, chat::errors::OllamaError::MissingMessages));
}

#[tokio::test]
async fn test_chat_completions_no_user_message() {
    let (server, provider) = setup().await;

    Mock::given(method("GET"))
        .and(path("/api/tags"))
        .respond_with(ResponseTemplate::new(200).set_body_json(models_response(&["llama3"])))
        .mount(&server)
        .await;

    let err = provider
        .chat_completions(json!({
            "model": "llama3",
            "messages": [{ "role": "system", "content": "be helpful" }]
        }))
        .await
        .unwrap_err();
    assert!(matches!(err, chat::errors::OllamaError::MissingMessages));
}

#[tokio::test]
async fn test_chat_completions_model_not_found() {
    let (server, provider) = setup().await;

    Mock::given(method("GET"))
        .and(path("/api/tags"))
        .respond_with(ResponseTemplate::new(200).set_body_json(models_response(&["llama3"])))
        .mount(&server)
        .await;

    let err = provider
        .chat_completions(json!({
            "model": "gpt-4",
            "messages": [{ "role": "user", "content": "hi" }]
        }))
        .await
        .unwrap_err();
    assert!(matches!(err, chat::errors::OllamaError::ModelNotFound(_)));
}

// ── load_model ────────────────────────────────────────────────────────────────

#[tokio::test]
async fn test_load_model_ok() {
    let (server, provider) = setup().await;

    Mock::given(method("GET"))
        .and(path("/api/tags"))
        .respond_with(ResponseTemplate::new(200).set_body_json(models_response(&["llama3"])))
        .mount(&server)
        .await;

    Mock::given(method("POST"))
        .and(path("/api/generate"))
        .respond_with(ResponseTemplate::new(200).set_body_json(json!({
            "model": "llama3",
            "done":  true,
        })))
        .mount(&server)
        .await;

    let res = provider.load_model("llama3", Some("10m")).await.unwrap();

    assert_eq!(res["model"], "llama3");
    assert_eq!(res["status"], "loaded");
    assert_eq!(res["keep_alive"], "10m");
}

#[tokio::test]
async fn test_load_model_default_keep_alive() {
    let (server, provider) = setup().await;

    Mock::given(method("GET"))
        .and(path("/api/tags"))
        .respond_with(ResponseTemplate::new(200).set_body_json(models_response(&["llama3"])))
        .mount(&server)
        .await;

    Mock::given(method("POST"))
        .and(path("/api/generate"))
        .respond_with(ResponseTemplate::new(200).set_body_json(json!({
            "model": "llama3",
            "done":  true,
        })))
        .mount(&server)
        .await;

    let res = provider.load_model("llama3", None).await.unwrap();

    assert_eq!(res["status"], "loaded");
    assert_eq!(res["keep_alive"], "5m"); // default
}

#[tokio::test]
async fn test_load_model_not_found() {
    let (server, provider) = setup().await;

    Mock::given(method("GET"))
        .and(path("/api/tags"))
        .respond_with(ResponseTemplate::new(200).set_body_json(models_response(&["llama3"])))
        .mount(&server)
        .await;

    let err = provider.load_model("gpt-4", Some("10m")).await.unwrap_err();
    assert!(matches!(err, chat::errors::OllamaError::ModelNotFound(_)));
}

#[tokio::test]
async fn test_load_model_invalid_keep_alive() {
    let (server, provider) = setup().await;

    Mock::given(method("GET"))
        .and(path("/api/tags"))
        .respond_with(ResponseTemplate::new(200).set_body_json(models_response(&["llama3"])))
        .mount(&server)
        .await;

    let err = provider
        .load_model("llama3", Some("10x"))
        .await
        .unwrap_err();
    assert!(matches!(
        err,
        chat::errors::OllamaError::InvalidKeepAlive(_)
    ));
}

#[tokio::test]
async fn test_load_model_keep_alive_plain_integer() {
    let (server, provider) = setup().await;

    Mock::given(method("GET"))
        .and(path("/api/tags"))
        .respond_with(ResponseTemplate::new(200).set_body_json(models_response(&["llama3"])))
        .mount(&server)
        .await;

    Mock::given(method("POST"))
        .and(path("/api/generate"))
        .respond_with(ResponseTemplate::new(200).set_body_json(json!({
            "model": "llama3",
            "done":  true,
        })))
        .mount(&server)
        .await;

    // plain integers (seconds) and "-1" are valid
    let res = provider.load_model("llama3", Some("3600")).await.unwrap();
    assert_eq!(res["status"], "loaded");

    let res = provider.load_model("llama3", Some("-1")).await.unwrap();
    assert_eq!(res["status"], "loaded");
}

// ── unload_model ──────────────────────────────────────────────────────────────

#[tokio::test]
async fn test_unload_model_ok() {
    let (server, provider) = setup().await;

    Mock::given(method("GET"))
        .and(path("/api/tags"))
        .respond_with(ResponseTemplate::new(200).set_body_json(models_response(&["llama3"])))
        .mount(&server)
        .await;

    Mock::given(method("POST"))
        .and(path("/api/generate"))
        .respond_with(ResponseTemplate::new(200).set_body_json(json!({
            "model": "llama3",
            "done":  true,
        })))
        .mount(&server)
        .await;

    let res = provider.unload_model("llama3").await.unwrap();

    assert_eq!(res["model"], "llama3");
    assert_eq!(res["status"], "unloaded");
    // no keep_alive field on unload response
    assert!(res.get("keep_alive").is_none());
}

#[tokio::test]
async fn test_unload_model_not_found() {
    let (server, provider) = setup().await;

    Mock::given(method("GET"))
        .and(path("/api/tags"))
        .respond_with(ResponseTemplate::new(200).set_body_json(models_response(&["llama3"])))
        .mount(&server)
        .await;

    let err = provider.unload_model("gpt-4").await.unwrap_err();
    assert!(matches!(err, chat::errors::OllamaError::ModelNotFound(_)));
}