refactor: Turn link-info into its own element and class (#5178)

src/providers/links/LinkInfo.hpp

@@ -0,0 +1,135 @@
+#pragma once
+
+#include "messages/Image.hpp"
+
+namespace chatterino {
+
+/// @brief Rich info about a URL with tooltip and thumbnail
+///
+/// This is only a data class - it doesn't do the resolving.
+/// It can only be used from the GUI thread.
+class LinkInfo : public QObject
+{
+    Q_OBJECT
+
+public:
+    /// @brief the state of a link info
+    ///
+    /// The state of a link can only increase. For example, it's not possible
+    /// for the link to change from "Resolved" to "Loading".
+    enum class State {
+        /// @brief The object was created, no info is resolved
+        ///
+        /// This is the initial state
+        Created,
+        /// Info is currently loading
+        Loading,
+        /// Info has been resolved and the properties have been updated
+        Resolved,
+        /// There has been an error resolving the link info (e.g. timeout)
+        Errored,
+    };
+
+    /// @brief Constructs a new link info for a URL
+    ///
+    /// This doesn't load any link info.
+    /// @see #ensureLoadingStarted()
+    [[nodiscard]] explicit LinkInfo(QString url);
+
+    ~LinkInfo() override;
+
+    LinkInfo(const LinkInfo &) = delete;
+    LinkInfo(LinkInfo &&) = delete;
+    LinkInfo &operator=(const LinkInfo &) = delete;
+    LinkInfo &operator=(LinkInfo &&) = delete;
+
+    /// @brief The URL of this link
+    ///
+    /// If the "unshortLinks" setting is enabled, this can change after the
+    /// link is resolved.
+    [[nodiscard]] QString url() const;
+
+    /// @brief The URL of this link as seen in the message
+    ///
+    /// If the "unshortLinks" setting doesn't affect this URL.
+    [[nodiscard]] QString originalUrl() const;
+
+    /// Returns the current state
+    [[nodiscard]] State state() const;
+
+    /// Returns true if this link has not yet been resolved (it's "Created")
+    [[nodiscard]] bool isPending() const;
+
+    /// Returns true if the info is loading
+    [[nodiscard]] bool isLoading() const;
+
+    /// Returns true if the info is loaded (resolved or errored)
+    [[nodiscard]] bool isLoaded() const;
+
+    /// Returns true if this link has been resolved
+    [[nodiscard]] bool isResolved() const;
+
+    /// Returns true if the info failed to resolve
+    [[nodiscard]] bool hasError() const;
+
+    /// Returns true if this link has a thumbnail
+    [[nodiscard]] bool hasThumbnail() const;
+
+    /// @brief Returns the tooltip of this link
+    ///
+    /// The tooltip contains the URL of the link and any info added by the
+    /// resolver. Resolvers must include the URL.
+    [[nodiscard]] QString tooltip() const;
+
+    /// @brief Returns the thumbnail of this link
+    ///
+    /// The thumbnail is provided by the resolver and might not have been
+    /// loaded yet.
+    ///
+    /// @pre The caller must check #hasThumbnail() before calling this method
+    [[nodiscard]] ImagePtr thumbnail() const;
+
+    /// @brief Updates the state and emits #stateChanged accordingly
+    ///
+    /// @pre The caller must be in the GUI thread.
+    /// @pre @a state must be greater or equal to the current state.
+    /// @see #state(), #stateChanged
+    void setState(State state);
+
+    /// @brief Updates the resolved url of this link
+    ///
+    /// @pre The caller must be in the GUI thread.
+    /// @see #url()
+    void setResolvedUrl(QString resolvedUrl);
+
+    /// @brief Updates the tooltip of this link
+    ///
+    /// @pre The caller must be in the GUI thread.
+    /// @see #tooltip()
+    void setTooltip(QString tooltip);
+
+    /// @brief Updates the thumbnail of this link
+    ///
+    /// The thumbnail is allowed to be empty or nullptr.
+    ///
+    /// @pre The caller must be in the GUI thread.
+    /// @see #hasThumbnail(), #thumbnail()
+    void setThumbnail(ImagePtr thumbnail);
+
+signals:
+    /// @brief Emitted when this link's state changes
+    ///
+    /// @param state The new state
+    void stateChanged(State state);
+
+private:
+    const QString originalUrl_;
+    QString url_;
+
+    QString tooltip_;
+    ImagePtr thumbnail_;
+
+    State state_ = State::Created;
+};
+
+}  // namespace chatterino