/* 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 http://mozilla.org/MPL/2.0/. */

//! This module defines the custom configurations that consumers can set.
//! Those configurations override default values and can be used to set a custom server,
//! collection name, and bucket name.
//! The purpose of the configuration parameters are to allow consumers an easy debugging option,
//! and the ability to be explicit about the server.

use url::Url;

use crate::error::warn;
use crate::{ApiResult, Error, RemoteSettingsContext, Result};

/// Remote settings configuration
///
/// This is the version used in the new API, hence the `2` at the end.  The plan is to move
/// consumers to the new API, remove the RemoteSettingsConfig struct, then remove the `2` from this
/// name.
#[derive(Debug, Default, Clone, uniffi::Record)]
pub struct RemoteSettingsConfig2 {
    /// The Remote Settings server to use. Defaults to [RemoteSettingsServer::Prod],
    #[uniffi(default = None)]
    pub server: Option<RemoteSettingsServer>,
    /// Bucket name to use, defaults to "main".  Use "main-preview" for a preview bucket
    #[uniffi(default = None)]
    pub bucket_name: Option<String>,
    /// App context to use for JEXL filtering (when the `jexl` feature is present).
    #[uniffi(default = None)]
    pub app_context: Option<RemoteSettingsContext>,
}

/// Custom configuration for the client.
/// Currently includes the following:
/// - `server`: The Remote Settings server to use. If not specified, defaults to the production server (`RemoteSettingsServer::Prod`).
/// - `server_url`: An optional custom Remote Settings server URL. Deprecated; please use `server` instead.
/// - `bucket_name`: The optional name of the bucket containing the collection on the server. If not specified, the standard bucket will be used.
/// - `collection_name`: The name of the collection for the settings server.
#[derive(Debug, Clone, uniffi::Record)]
pub struct RemoteSettingsConfig {
    pub collection_name: String,
    #[uniffi(default = None)]
    pub bucket_name: Option<String>,
    #[uniffi(default = None)]
    pub server_url: Option<String>,
    #[uniffi(default = None)]
    pub server: Option<RemoteSettingsServer>,
}

/// The Remote Settings server that the client should use.
#[derive(Debug, Clone, uniffi::Enum)]
pub enum RemoteSettingsServer {
    Prod,
    Stage,
    Dev,
    Custom { url: String },
}

impl RemoteSettingsServer {
    /// Get the [url::Url] for this server
    #[error_support::handle_error(Error)]
    pub fn url(&self) -> ApiResult<Url> {
        self.get_url()
    }

    /// Get a BaseUrl for this server
    pub fn get_base_url(&self) -> Result<BaseUrl> {
        let base_url = BaseUrl::parse(self.raw_url())?;
        // Custom URLs are weird and require a couple tricks for backwards compatibility.
        // Normally we append `v1/` to match how this has historically worked.  However,
        // don't do this for file:// schemes which normally don't make any sense, but it's
        // what Nimbus uses to indicate they want to use the file-based client, rather than
        // a remote-settings based one.
        if base_url.url().scheme() != "file" {
            Ok(base_url.join("v1"))
        } else {
            Ok(base_url)
        }
    }

    /// get_url() that never fails
    ///
    /// If the URL is invalid, we'll log a warning and fall back to the production URL
    pub fn get_base_url_with_prod_fallback(&self) -> BaseUrl {
        match self.get_base_url() {
            Ok(url) => url,
            // The unwrap below will never fail, since prod is a hard-coded/valid URL.
            Err(_) => {
                warn!("Invalid Custom URL: {}", self.raw_url());
                BaseUrl::parse(Self::Prod.raw_url()).unwrap()
            }
        }
    }

    fn raw_url(&self) -> &str {
        match self {
            Self::Prod => "https://firefox.settings.services.mozilla.com/v1",
            Self::Stage => "https://firefox.settings.services.allizom.org/v1",
            Self::Dev => "https://remote-settings-dev.allizom.org/v1",
            Self::Custom { url } => url,
        }
    }

    /// Internal version of `url()`.
    ///
    /// The difference is that it uses `Error` instead of `ApiError`.  This is what we need to use
    /// inside the crate.
    pub fn get_url(&self) -> Result<Url> {
        Ok(match self {
            Self::Prod => Url::parse("https://firefox.settings.services.mozilla.com/v1")?,
            Self::Stage => Url::parse("https://firefox.settings.services.allizom.org/v1")?,
            Self::Dev => Url::parse("https://remote-settings-dev.allizom.org/v1")?,
            Self::Custom { url } => {
                let mut url = Url::parse(url)?;
                // Custom URLs are weird and require a couple tricks for backwards compatibility.
                // Normally we append `v1/` to match how this has historically worked.  However,
                // don't do this for file:// schemes which normally don't make any sense, but it's
                // what Nimbus uses to indicate they want to use the file-based client, rather than
                // a remote-settings based one.
                if url.scheme() != "file" {
                    url = url.join("v1")?
                }
                url
            }
        })
    }
}

/// Url that's guaranteed safe to use as a base
#[derive(Debug, Clone)]
pub struct BaseUrl {
    url: Url,
}

impl BaseUrl {
    pub fn parse(url: &str) -> Result<Self> {
        let url = Url::parse(url)?;
        if url.cannot_be_a_base() {
            Err(Error::UrlParsingError(
                url::ParseError::RelativeUrlWithCannotBeABaseBase,
            ))
        } else {
            Ok(Self { url })
        }
    }

    pub fn url(&self) -> &Url {
        &self.url
    }

    pub fn into_inner(self) -> Url {
        self.url
    }

    pub fn join(&self, input: &str) -> BaseUrl {
        Self {
            // Unwrap is safe, because the join() docs say that it only will error for
            // cannot-be-a-base URLs.
            url: self.url.join(input).unwrap(),
        }
    }

    pub fn path_segments_mut(&mut self) -> url::PathSegmentsMut<'_> {
        // Unwrap is safe, because the path_segments_mut() docs say that it only will
        // error for cannot-be-a-base URLs.
        self.url.path_segments_mut().unwrap()
    }

    pub fn query_pairs_mut(&mut self) -> url::form_urlencoded::Serializer<'_, url::UrlQuery<'_>> {
        self.url.query_pairs_mut()
    }
}