use std::time::Duration;

use axum::{http::HeaderMap, response::IntoResponse, Extension, Json};
use tetratto_core::model::{
    auth::{User, Notification},
    moderation::AuditLogEntry,
    permissions::FinePermission,
    ApiReturn, Error,
};
use stripe::{EventObject, EventType};
use crate::State;

pub async fn stripe_webhook(
    Extension(data): Extension<State>,
    headers: HeaderMap,
    body: String,
) -> impl IntoResponse {
    let data = &(data.read().await).0;

    let stripe_cnf = match data.0.0.stripe {
        Some(ref c) => c,
        None => return Json(Error::MiscError("Disabled".to_string()).into()),
    };

    let sig = match headers.get("Stripe-Signature") {
        Some(s) => s,
        None => return Json(Error::NotAllowed.into()),
    };

    let req = match stripe::Webhook::construct_event(
        &body,
        sig.to_str().unwrap(),
        &data.0.0.stripe.as_ref().unwrap().webhook_signing_secret,
    ) {
        Ok(e) => e,
        Err(e) => return Json(Error::MiscError(e.to_string()).into()),
    };

    match req.type_ {
        EventType::CheckoutSessionCompleted => {
            // checkout session ended, store user customer id (from stripe) in their user data
            let session = match req.data.object {
                EventObject::CheckoutSession(c) => c,
                _ => unreachable!("cannot be this"),
            };

            let user_id = session
                .client_reference_id
                .unwrap()
                .parse::<usize>()
                .unwrap();

            let customer_id = session.customer.unwrap().id();

            let user = match data.get_user_by_id(user_id).await {
                Ok(ua) => ua,
                Err(e) => return Json(e.into()),
            };

            tracing::info!("payment {} (stripe: {})", user.id, customer_id);
            if let Err(e) = data
                .update_user_stripe_id(user.id, customer_id.as_str())
                .await
            {
                return Json(e.into());
            }
        }
        EventType::InvoicePaymentSucceeded => {
            // payment finished and subscription created
            // we're doing this *instead* of CustomerSubscriptionCreated because
            // the invoice happens *after* the checkout session ends... which is what we need
            let invoice = match req.data.object {
                EventObject::Invoice(c) => c,
                _ => unreachable!("cannot be this"),
            };

            let customer_id = invoice.customer.unwrap().id();
            let lines = invoice.lines.unwrap();

            if lines.total_count.unwrap() > 1 {
                if let Err(e) = data
                    .create_audit_log_entry(AuditLogEntry::new(
                        0,
                        format!("too many invoice line items: stripe {customer_id}"),
                    ))
                    .await
                {
                    return Json(e.into());
                }

                return Json(Error::MiscError("Too many line items".to_string()).into());
            }

            let item = match lines.data.get(0) {
                Some(i) => i,
                None => {
                    if let Err(e) = data
                        .create_audit_log_entry(AuditLogEntry::new(
                            0,
                            format!("too few invoice line items: stripe {customer_id}"),
                        ))
                        .await
                    {
                        return Json(e.into());
                    }

                    return Json(Error::MiscError("Too few line items".to_string()).into());
                }
            };

            let product_id = item
                .price
                .as_ref()
                .unwrap()
                .product
                .as_ref()
                .unwrap()
                .id()
                .to_string();

            // pull user and update role
            let mut retries: usize = 0;
            let mut user: Option<User> = None;

            loop {
                if retries >= 5 {
                    // we've already tried 5 times (25 seconds of waiting)... it's not
                    // going to happen
                    //
                    // we're going to report this error to the audit log so someone can
                    // check manually later
                    if let Err(e) = data
                        .create_audit_log_entry(AuditLogEntry::new(
                            0,
                            format!("invoice tier update failed: stripe {customer_id}"),
                        ))
                        .await
                    {
                        return Json(e.into());
                    }

                    return Json(Error::GeneralNotFound("user".to_string()).into());
                }

                match data.get_user_by_stripe_id(customer_id.as_str()).await {
                    Ok(ua) => {
                        if !user.is_none() {
                            break;
                        }

                        user = Some(ua);
                        break;
                    }
                    Err(_) => {
                        tracing::info!("checkout session not stored in db yet");
                        retries += 1;
                        tokio::time::sleep(Duration::from_secs(5)).await;
                        continue;
                    }
                }
            }

            let user = user.unwrap();

            if product_id == stripe_cnf.product_ids.supporter {
                // supporter
                tracing::info!("found subscription user in {retries} tries");

                if user.permissions.check(FinePermission::SUPPORTER) {
                    return Json(ApiReturn {
                        ok: true,
                        message: "Already applied".to_string(),
                        payload: (),
                    });
                }

                tracing::info!("invoice {} (stripe: {})", user.id, customer_id);
                let new_user_permissions = user.permissions | FinePermission::SUPPORTER;

                if let Err(e) = data
                    .update_user_role(user.id, new_user_permissions, user.clone(), true)
                    .await
                {
                    return Json(e.into());
                }

                if data.0.0.security.enable_invite_codes && user.awaiting_purchase {
                    if let Err(e) = data
                        .update_user_awaiting_purchased_status(user.id, false, user.clone(), false)
                        .await
                    {
                        return Json(e.into());
                    }
                }

                if let Err(e) = data
                    .create_notification(Notification::new(
                        "Welcome new supporter!".to_string(),
                        "Thank you for your support! Your account has been updated with your new role."
                            .to_string(),
                        user.id,
                    ))
                    .await
                {
                    return Json(e.into());
                }
            } else {
                tracing::error!(
                    "received an invalid stripe product id, please check config.stripe.product_ids"
                );
                return Json(Error::MiscError("Unknown product ID".to_string()).into());
            }
        }
        EventType::CustomerSubscriptionDeleted => {
            // payment failed and subscription deleted
            let subscription = match req.data.object {
                EventObject::Subscription(c) => c,
                _ => unreachable!("cannot be this"),
            };

            let customer_id = subscription.customer.id();

            let user = match data.get_user_by_stripe_id(customer_id.as_str()).await {
                Ok(ua) => ua,
                Err(e) => return Json(e.into()),
            };

            tracing::info!("unsubscribe {} (stripe: {})", user.id, customer_id);
            let new_user_permissions = user.permissions - FinePermission::SUPPORTER;

            if let Err(e) = data
                .update_user_role(user.id, new_user_permissions, user.clone(), true)
                .await
            {
                return Json(e.into());
            }

            if data.0.0.security.enable_invite_codes && user.was_purchased && user.invite_code == 0
            {
                // user doesn't come from an invite code, and is a purchased account
                // this means their account must be locked if they stop paying
                if let Err(e) = data
                    .update_user_awaiting_purchased_status(user.id, true, user.clone(), false)
                    .await
                {
                    return Json(e.into());
                }
            }

            if let Err(e) = data
                .create_notification(Notification::new(
                    "Sorry to see you go... :(".to_string(),
                    "Thank you for your past support! Please feel free to leave us feedback on why you decided to cancel."
                        .to_string(),
                    user.id,
                ))
                .await
            {
                return Json(e.into());
            }
        }
        EventType::InvoicePaymentFailed => {
            // payment failed
            let subscription = match req.data.object {
                EventObject::Subscription(c) => c,
                _ => unreachable!("cannot be this"),
            };

            let customer_id = subscription.customer.id();

            let user = match data.get_user_by_stripe_id(customer_id.as_str()).await {
                Ok(ua) => ua,
                Err(e) => return Json(e.into()),
            };

            tracing::info!(
                "unsubscribe (pay fail) {} (stripe: {})",
                user.id,
                customer_id
            );
            let new_user_permissions = user.permissions - FinePermission::SUPPORTER;

            if let Err(e) = data
                .update_user_role(user.id, new_user_permissions, user.clone(), true)
                .await
            {
                return Json(e.into());
            }

            if data.0.0.security.enable_invite_codes && user.was_purchased && user.invite_code == 0
            {
                // user doesn't come from an invite code, and is a purchased account
                // this means their account must be locked if they stop paying
                if let Err(e) = data
                    .update_user_awaiting_purchased_status(user.id, true, user.clone(), false)
                    .await
                {
                    return Json(e.into());
                }
            }

            if let Err(e) = data
                .create_notification(Notification::new(
                    "It seems your recent payment has failed :(".to_string(),
                    "No worries! Your subscription is still active and will be retried. Your supporter status will resume when you have a successful payment."
                        .to_string(),
                    user.id,
                ))
                .await
            {
                return Json(e.into());
            }
        }
        _ => return Json(Error::Unknown.into()),
    }

    Json(ApiReturn {
        ok: true,
        message: "Acceptable".to_string(),
        payload: (),
    })
}