use std::{fs, path::Path};

use axum::{
    Router,
    body::Body,
    http::{Request, StatusCode, header},
};
use http_body_util::BodyExt;
use serde_json::{Value, json};
use tempfile::TempDir;
use tower::ServiceExt;

async fn test_app() -> (Router, TempDir) {
    let temp_dir = TempDir::new().expect("temporary directory should be created");
    let pool = task_pilot_backend::database::connect("sqlite::memory:")
        .await
        .expect("test database should initialize");
    let app = task_pilot_backend::app(pool, temp_dir.path().join("logs"))
        .await
        .expect("test app should start");
    (app, temp_dir)
}

async fn fetch_token(app: &Router) -> String {
    let response = app
        .clone()
        .oneshot(
            Request::builder()
                .uri("/api/v1/session")
                .body(Body::empty())
                .expect("request should build"),
        )
        .await
        .expect("router should respond");
    let body = response
        .into_body()
        .collect()
        .await
        .expect("session body should be readable")
        .to_bytes();
    let json: Value = serde_json::from_slice(&body).expect("session should be JSON");

    json["token"]
        .as_str()
        .expect("session token should be a string")
        .to_owned()
}

async fn post_probe(app: &Router, token: Option<&str>, payload: Value) -> (StatusCode, Value) {
    post_json(app, "/api/v1/python/venv", token, payload).await
}

async fn post_create(app: &Router, token: Option<&str>, payload: Value) -> (StatusCode, Value) {
    post_json(app, "/api/v1/python/venv/create", token, payload).await
}

async fn post_json(
    app: &Router,
    uri: &str,
    token: Option<&str>,
    payload: Value,
) -> (StatusCode, Value) {
    let mut builder = Request::builder()
        .method("POST")
        .uri(uri)
        .header(header::CONTENT_TYPE, "application/json");
    if let Some(token) = token {
        builder = builder.header("x-taskpilot-token", token);
    }
    let response = app
        .clone()
        .oneshot(
            builder
                .body(Body::from(payload.to_string()))
                .expect("request should build"),
        )
        .await
        .expect("router should respond");
    let status = response.status();
    let body = response
        .into_body()
        .collect()
        .await
        .expect("response body should be readable")
        .to_bytes();

    (status, serde_json::from_slice(&body).unwrap_or(Value::Null))
}

fn create_fake_venv(project: &Path) {
    let venv = project.join(".venv");
    fs::create_dir_all(venv.join("Scripts")).expect("venv directory should be created");
    fs::write(venv.join("pyvenv.cfg"), "home = C:\\Python\n")
        .expect("pyvenv.cfg should be written");
    fs::write(venv.join("Scripts").join("python.exe"), "")
        .expect("python.exe placeholder should be written");
}

#[tokio::test]
async fn venv_probe_requires_management_token() {
    let (app, _temp_dir) = test_app().await;

    let (status, body) = post_probe(
        &app,
        None,
        json!({ "working_dir": ".", "interpreter": "python.exe" }),
    )
    .await;

    assert_eq!(status, StatusCode::FORBIDDEN);
    assert_eq!(body["code"], "FORBIDDEN");
}

#[tokio::test]
async fn venv_probe_reports_linked_environment() {
    let (app, temp_dir) = test_app().await;
    let project = temp_dir.path().join("project");
    fs::create_dir_all(&project).expect("project directory should be created");
    create_fake_venv(&project);
    let token = fetch_token(&app).await;

    let (status, body) = post_probe(
        &app,
        Some(&token),
        json!({
            "working_dir": project.to_str().expect("project path should be UTF-8"),
            "interpreter": "python.exe",
            "venv": null
        }),
    )
    .await;

    assert_eq!(status, StatusCode::OK);
    assert_eq!(body["status"], "linked");
    assert_eq!(body["interpreter_kind"], "python");
    assert_eq!(body["source"], "working_directory");
    let expected_python = Path::new(".venv")
        .join("Scripts")
        .join("python.exe")
        .to_string_lossy()
        .into_owned();
    assert_eq!(body["display_path"], expected_python);
    assert_eq!(
        body["venv_path"],
        project.join(".venv").to_string_lossy().into_owned()
    );
}

#[tokio::test]
async fn venv_probe_skips_non_python_interpreters() {
    let (app, temp_dir) = test_app().await;
    let token = fetch_token(&app).await;

    let (status, body) = post_probe(
        &app,
        Some(&token),
        json!({
            "working_dir": temp_dir.path().to_str().expect("temp path should be UTF-8"),
            "interpreter": "node.exe"
        }),
    )
    .await;

    assert_eq!(status, StatusCode::OK);
    assert_eq!(body["status"], "not_applicable");
    assert_eq!(body["interpreter_kind"], "node");
    assert_eq!(body["display_path"], "node.exe");
}

#[tokio::test]
async fn venv_probe_reports_missing_working_directory() {
    let (app, temp_dir) = test_app().await;
    let token = fetch_token(&app).await;
    let absent = temp_dir.path().join("absent");

    let (status, body) = post_probe(
        &app,
        Some(&token),
        json!({
            "working_dir": absent.to_str().expect("absent path should be UTF-8"),
            "interpreter": "python.exe"
        }),
    )
    .await;

    assert_eq!(status, StatusCode::OK);
    assert_eq!(body["status"], "incomplete");
    assert!(
        body["message"]
            .as_str()
            .expect("message should be a string")
            .contains("工作目录")
    );
}

#[tokio::test]
async fn venv_probe_reports_project_dependency_files() {
    let (app, temp_dir) = test_app().await;
    let token = fetch_token(&app).await;
    let project = temp_dir.path().join("deps-project");
    fs::create_dir_all(&project).expect("project directory should be created");
    fs::write(
        project.join("pyproject.toml"),
        "[project]\nname = \"demo\"\n",
    )
    .expect("pyproject.toml should be written");
    fs::write(project.join("requirements.txt"), "").expect("requirements.txt should be written");

    let (status, body) = post_probe(
        &app,
        Some(&token),
        json!({
            "working_dir": project.to_str().expect("project path should be UTF-8"),
            "interpreter": "python.exe"
        }),
    )
    .await;

    assert_eq!(status, StatusCode::OK);
    assert_eq!(body["status"], "missing");
    assert_eq!(body["has_pyproject"], true);
    assert_eq!(body["has_requirements"], true);
    assert_eq!(body["requirements_files"], json!(["requirements.txt"]));
    assert_eq!(body["can_create"], body["uv_available"]);
}

#[tokio::test]
async fn venv_create_rejects_missing_working_directory() {
    let (app, temp_dir) = test_app().await;
    let token = fetch_token(&app).await;
    let absent = temp_dir.path().join("absent-project");

    let (status, body) = post_create(
        &app,
        Some(&token),
        json!({
            "working_dir": absent.to_str().expect("absent path should be UTF-8")
        }),
    )
    .await;

    assert_eq!(status, StatusCode::BAD_REQUEST);
    assert_eq!(body["code"], "VENV_CREATE_FAILED");
    assert!(
        body["message"]
            .as_str()
            .expect("message should be a string")
            .contains("工作目录")
    );
}

#[tokio::test]
async fn venv_create_requires_management_token() {
    let (app, temp_dir) = test_app().await;

    let (status, body) = post_create(
        &app,
        None,
        json!({
            "working_dir": temp_dir.path().to_str().expect("temp path should be UTF-8")
        }),
    )
    .await;

    assert_eq!(status, StatusCode::FORBIDDEN);
    assert_eq!(body["code"], "FORBIDDEN");
}