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

use chat::dto::api;
use chat::errors::OllamaError;
use chat::providers::ollama::client::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 req = api::CompletionRequest {
        base: api::BaseLLMRequest {
            model: "llama3".to_string(),
            ..Default::default()
        },
        prompt: "Hello".to_string(),
    };

    let res = provider.completions(&req).await.unwrap();

    assert_eq!(res.object, api::CompletionObject::TextCompletion);

    assert_eq!(res.choices.len(), 1);
    assert_eq!(res.choices[0].text, "I am a helpful assistant.");
    assert_eq!(res.choices[0].finish_reason, api::FinishReason::Stop);

    assert_eq!(res.usage.prompt_tokens, 10);
    assert_eq!(res.usage.completion_tokens, 8);
    assert_eq!(res.usage.total_tokens, 18);
}

#[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 req = api::CompletionRequest {
        base: api::BaseLLMRequest {
            model: "llama3".to_string(),
            ..Default::default()
        },
        prompt: "".to_string(),
    };

    let err = provider.completions(&req).await.unwrap_err();

    assert!(matches!(err, 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 req = api::CompletionRequest {
        base: api::BaseLLMRequest {
            model: "llama3".to_string(),
            ..Default::default()
        },
        prompt: "   ".to_string(),
    };

    let err = provider.completions(&req).await.unwrap_err();

    assert!(matches!(err, 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 req = api::CompletionRequest {
        base: api::BaseLLMRequest {
            model: "gpt-4".to_string(),
            ..Default::default()
        },
        prompt: "hello".to_string(),
    };

    let err = provider.completions(&req).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,
            "prompt_eval_count": 5,
            "eval_count": 2
        })))
        .mount(&server)
        .await;

    let req = api::ChatRequest {
        base: api::BaseLLMRequest {
            model: "llama3".to_string(),
            ..Default::default()
        },
        messages: vec![api::Message {
            role: api::Role::User,
            content: "What is 2+2?".to_string(),
        }],
    };

    let res = provider.chat_completions(&req).await.unwrap();

    assert_eq!(res.object, "chat.completion");
    assert_eq!(res.choices.len(), 1);

    assert_eq!(res.choices[0].message.role, api::Role::Assistant);
    assert_eq!(res.choices[0].message.content, "4.");

    assert_eq!(res.choices[0].finish_reason, api::FinishReason::Stop);

    let usage = res.usage.unwrap();
    assert_eq!(usage.prompt_tokens, 5);
    assert_eq!(usage.completion_tokens, 2);
    assert_eq!(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 req = api::ChatRequest {
        base: api::BaseLLMRequest {
            model: "llama3".to_string(),
            ..Default::default()
        },
        messages: vec![],
    };

    let err = provider.chat_completions(&req).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 req = api::ChatRequest {
        base: api::BaseLLMRequest {
            model: "llama3".to_string(),
            ..Default::default()
        },
        messages: vec![api::Message {
            role: api::Role::System,
            content: "be helpful".to_string(),
        }],
    };

    let err = provider.chat_completions(&req).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 req = api::ChatRequest {
        base: api::BaseLLMRequest {
            model: "gpt-4".to_string(),
            ..Default::default()
        },
        messages: vec![api::Message {
            role: api::Role::User,
            content: "hi".to_string(),
        }],
    };

    let err = provider.chat_completions(&req).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",
            "response": "ok",
            "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_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;

    let res = provider.load_model("llama3", Some("3600")).await.unwrap();

    assert_eq!(res.status, "loaded");
    assert_eq!(res.keep_alive, "3600");

    let res = provider.load_model("llama3", Some("-1")).await.unwrap();

    assert_eq!(res.status, "loaded");
    assert_eq!(res.keep_alive, "-1");
}

// // ── 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",
            "response": "ok",
            "done":  true,
        })))
        .mount(&server)
        .await;

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

    assert_eq!(res.model, "llama3");
    assert_eq!(res.status, "unloaded");
}

#[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(_)));
}