use std::sync::Arc;

use api_types::{Credentials, Me, OkResp, RootInfo, UserInfo};
use axum::Json;
use axum::extract::State;
use axum::http::{HeaderMap, StatusCode, header};
use axum::response::{IntoResponse, Response};
use serde::Deserialize;

use crate::api::common::{display_name, hash_password, validate_account_name, validate_password};
use crate::auth::{self, clear_session_cookie, parse_session_cookie, session_cookie};
use crate::db::User;
use crate::error::{ApiError, AppState};

/// GET /api/auth/me
///
/// - No users at all → `200 {"first_boot": true}`
/// - No/invalid session → `401`
/// - Valid session → user info + visible roots
pub async fn me(
    State(state): State<Arc<AppState>>,
    headers: HeaderMap,
) -> Result<Json<Me>, ApiError> {
    if state.db.user_count().await? == 0 {
        return Ok(Json(Me {
            first_boot: true,
            user: None,
            roots: Vec::new(),
            allow_writable_shares: false,
        }));
    }

    let user = require_user(&state, &headers).await?;
    Ok(Json(me_for(&state, &user).await?))
}

/// The signed-in user behind the session cookie, or 401.
async fn require_user(state: &AppState, headers: &HeaderMap) -> Result<User, ApiError> {
    let Some(token) = parse_session_cookie(headers) else {
        return Err(ApiError::new(StatusCode::UNAUTHORIZED, "not signed in"));
    };
    state.db.session_user(&token).await?.ok_or_else(|| {
        ApiError::new(
            StatusCode::UNAUTHORIZED,
            "session expired, please sign in again",
        )
    })
}

/// Build the `/api/auth/me` payload for an authenticated user.
async fn me_for(state: &AppState, user: &User) -> Result<Me, ApiError> {
    let roots: Vec<RootInfo> = state
        .db
        .user_roots(user.id)
        .await?
        .into_iter()
        .map(|r| RootInfo {
            id: r.id,
            name: display_name(&state.root, &r.path),
            path: r.path,
            mode: r.mode,
        })
        .collect();

    Ok(Me {
        first_boot: false,
        user: Some(UserInfo {
            id: user.id,
            name: user.name.clone(),
            is_admin: user.is_admin,
            single_click_open: user.single_click,
        }),
        roots,
        allow_writable_shares: state.db.allow_writable_shares().await?,
    })
}

/// PUT /api/auth/me
///
/// Update the signed-in user's profile settings. Returns the fresh `/me`
/// payload so clients can apply the change immediately.
#[derive(Deserialize)]
pub(crate) struct ProfilePatch {
    pub single_click_open: bool,
}

pub async fn update_profile(
    State(state): State<Arc<AppState>>,
    headers: HeaderMap,
    Json(body): Json<ProfilePatch>,
) -> Result<Json<Me>, ApiError> {
    let mut user = require_user(&state, &headers).await?;
    state
        .db
        .set_user_single_click(user.id, body.single_click_open)
        .await?;
    user.single_click = body.single_click_open;
    Ok(Json(me_for(&state, &user).await?))
}

/// POST /api/auth/setup — create the first admin account.
/// Only available while no users exist.
pub async fn setup(
    State(state): State<Arc<AppState>>,
    Json(body): Json<Credentials>,
) -> Result<Response, ApiError> {
    let name = body.name.trim();
    validate_account_name(name)?;
    validate_password(&body.password)?;
    if state.db.user_count().await? > 0 {
        return Err(ApiError::new(
            StatusCode::CONFLICT,
            "server is already set up",
        ));
    }

    let pass_hash = hash_password(&body.password).await?;
    let user = state.db.create_admin(name, &pass_hash).await?;

    let token = auth::random_token();
    state.db.create_session(user.id, &token).await?;

    let mut res = Json(OkResp { ok: true }).into_response();
    res.headers_mut().insert(
        header::SET_COOKIE,
        session_cookie(&token, state.https).parse().unwrap(),
    );
    Ok(res)
}

/// POST /api/auth/login
pub async fn login(
    State(state): State<Arc<AppState>>,
    Json(body): Json<Credentials>,
) -> Result<Response, ApiError> {
    let Some(user) = state.db.verify_password(&body.name, &body.password).await? else {
        return Err(ApiError::new(
            StatusCode::UNAUTHORIZED,
            "invalid name or password",
        ));
    };

    let token = auth::random_token();
    state.db.create_session(user.id, &token).await?;

    let mut res = Json(OkResp { ok: true }).into_response();
    res.headers_mut().insert(
        header::SET_COOKIE,
        session_cookie(&token, state.https).parse().unwrap(),
    );
    Ok(res)
}

/// POST /api/auth/logout
pub async fn logout(State(state): State<Arc<AppState>>, headers: HeaderMap) -> Response {
    if let Some(token) = parse_session_cookie(&headers) {
        let _ = state.db.delete_session(&token).await;
    }
    let mut res = Json(OkResp { ok: true }).into_response();
    res.headers_mut().insert(
        header::SET_COOKIE,
        clear_session_cookie(state.https).parse().unwrap(),
    );
    res
}