// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at https://mozilla.org/MPL/2.0/.

use std::fmt;
use std::sync::Arc;

use crate::ping::PingMaker;
use crate::Glean;

use uuid::Uuid;

/// Stores information about a ping.
///
/// This is required so that given metric data queued on disk we can send
/// pings with the correct settings, e.g. whether it has a client_id.
#[derive(Clone)]
pub struct PingType(Arc<InnerPing>);

struct InnerPing {
    /// The name of the ping.
    pub name: String,
    /// Whether the ping should include the client ID.
    pub include_client_id: bool,
    /// Whether the ping should be sent if it is empty
    pub send_if_empty: bool,
    /// The "reason" codes that this ping can send
    pub reason_codes: Vec<String>,
}

impl fmt::Debug for PingType {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("PingType")
            .field("name", &self.0.name)
            .field("include_client_id", &self.0.include_client_id)
            .field("send_if_empty", &self.0.send_if_empty)
            .field("reason_codes", &self.0.reason_codes)
            .finish()
    }
}

// IMPORTANT:
//
// When changing this implementation, make sure all the operations are
// also declared in the related trait in `../traits/`.
impl PingType {
    /// Creates a new ping type for the given name, whether to include the client ID and whether to
    /// send this ping empty.
    ///
    /// # Arguments
    ///
    /// * `name` - The name of the ping.
    /// * `include_client_id` - Whether to include the client ID in the assembled ping when submitting.
    /// * `send_if_empty` - Whether the ping should be sent empty or not.
    /// * `reason_codes` - The valid reason codes for this ping.
    pub fn new<A: Into<String>>(
        name: A,
        include_client_id: bool,
        send_if_empty: bool,
        reason_codes: Vec<String>,
    ) -> Self {
        let this = Self(Arc::new(InnerPing {
            name: name.into(),
            include_client_id,
            send_if_empty,
            reason_codes,
        }));

        // Register this ping.
        // That will happen asynchronously and not block operation.
        crate::register_ping_type(&this);

        this
    }

    pub(crate) fn name(&self) -> &str {
        &self.0.name
    }

    pub(crate) fn include_client_id(&self) -> bool {
        self.0.include_client_id
    }

    pub(crate) fn send_if_empty(&self) -> bool {
        self.0.send_if_empty
    }

    /// Submits the ping for eventual uploading.
    ///
    /// The ping content is assembled as soon as possible, but upload is not
    /// guaranteed to happen immediately, as that depends on the upload policies.
    ///
    /// If the ping currently contains no content, it will not be sent,
    /// unless it is configured to be sent if empty.
    ///
    /// # Arguments
    ///
    /// * `reason` - the reason the ping was triggered. Included in the
    ///   `ping_info.reason` part of the payload.
    pub fn submit(&self, reason: Option<String>) {
        let ping = PingType(Arc::clone(&self.0));

        // Need to separate access to the Glean object from access to global state.
        // `trigger_upload` itself might lock the Glean object and we need to avoid that deadlock.
        crate::dispatcher::launch(|| {
            let sent =
                crate::core::with_glean(move |glean| ping.submit_sync(glean, reason.as_deref()));
            if sent {
                let state = crate::global_state().lock().unwrap();
                state.callbacks.trigger_upload();
            }
        })
    }

    /// Collects and submits a ping for eventual uploading.
    ///
    /// # Returns
    ///
    /// Whether the ping was succesfully assembled and queued.
    #[doc(hidden)]
    pub fn submit_sync(&self, glean: &Glean, reason: Option<&str>) -> bool {
        if !glean.is_upload_enabled() {
            log::info!("Glean disabled: not submitting any pings.");
            return false;
        }

        let ping = &self.0;
        let corrected_reason = match reason {
            Some(reason) => {
                if ping.reason_codes.contains(&reason.to_string()) {
                    Some(reason)
                } else {
                    log::error!("Invalid reason code {} for ping {}", reason, ping.name);
                    None
                }
            }
            None => None,
        };

        let ping_maker = PingMaker::new();
        let doc_id = Uuid::new_v4().to_string();
        let url_path = glean.make_path(&ping.name, &doc_id);
        match ping_maker.collect(glean, self, corrected_reason, &doc_id, &url_path) {
            None => {
                log::info!(
                    "No content for ping '{}', therefore no ping queued.",
                    ping.name
                );
                false
            }
            Some(ping) => {
                // This metric is recorded *after* the ping is collected (since
                // that is the only way to know *if* it will be submitted). The
                // implication of this is that the count for a metrics ping will
                // be included in the *next* metrics ping.
                glean
                    .additional_metrics
                    .pings_submitted
                    .get(ping.name)
                    .add_sync(glean, 1);

                if let Err(e) = ping_maker.store_ping(glean.get_data_path(), &ping) {
                    log::warn!("IO error while writing ping to file: {}. Enqueuing upload of what we have in memory.", e);
                    glean.additional_metrics.io_errors.add_sync(glean, 1);
                    // `serde_json::to_string` only fails if serialization of the content
                    // fails or it contains maps with non-string keys.
                    // However `ping.content` is already a `JsonValue`,
                    // so both scenarios should be impossible.
                    let content =
                        ::serde_json::to_string(&ping.content).expect("ping serialization failed");
                    glean.upload_manager.enqueue_ping(
                        glean,
                        ping.doc_id,
                        ping.url_path,
                        &content,
                        Some(ping.headers),
                    );
                    return true;
                }

                glean.upload_manager.enqueue_ping_from_file(glean, &doc_id);

                log::info!(
                    "The ping '{}' was submitted and will be sent as soon as possible",
                    ping.name
                );

                true
            }
        }
    }
}