Implement basic Mastodon API support

Implement support for OAuth 2.0 code entry, which is then used to
retrieve a token that is stored in the application's settings.
Authentification allowed the implementation of a basic "get post from
URL" feature mostly made for testing.

8 files changed, 253 insertions, 1 deletions

diff --git a/src/mainwindow.cpp b/src/mainwindow.cpp
index c6203d4..4ab0bb2 100644
--- a/src/mainwindow.cpp
+++ b/src/mainwindow.cpp
@@ -1,12 +1,15 @@
 #include "mainwindow.h"
 #include "./ui_mainwindow.h"
+#include "src/activitypub/appost.h"
 #include "src/archive/base_archive.h"
 #include "src/finddialog.h"
 #include "src/list_item.h"
 #include "src/command_line.h"
 #include "src/settingsdialog.h"
+#include "src/net/instance.h"
 
 #include <QFileDialog>
+#include <QInputDialog>
 #include <QMessageBox>
 #include <QRandomGenerator>
 #include <QClipboard>
@@ -148,6 +151,22 @@ void MainWindow::set_search_text(const QString &text) {
     ui->textInputSearch->setText(text);
 }
 
+void MainWindow::on_actionOpen_URL_triggered(bool checked) {
+    bool ok;
+    QString url = QInputDialog::getText(this, tr("Open status from URL"), tr("Status URL:"), QLineEdit::Normal, "https://…", &ok);
+
+    // TODO: Move all of this to another thread
+    // TODO: Reuse the Instance object
+    // Really hacky code but works as a PoC and allows testing
+    if (ok and not url.isEmpty()) {
+        Instance* instance = Instance::create_instance();
+        APPost* post = instance->get_post_from_url(url);
+        QString html = post->get_html_render({ui->statusInfoText->width(), &locale_context});
+        ui->statusInfoText->setHtml(html);
+        delete instance; instance = nullptr;
+    } else return;
+}
+
 void MainWindow::relist_statuses() {
     if (data_archive) {
         ui->listWidget->clear();
diff --git a/src/mainwindow.h b/src/mainwindow.h
index 4c7e034..24bc970 100644
--- a/src/mainwindow.h
+++ b/src/mainwindow.h
@@ -49,6 +49,7 @@ private slots:
     void on_actionRandom_status_triggered(bool checked);
     void on_actionCopy_status_triggered(bool checked);
     void on_actionFind_triggered(bool checked);
+    void on_actionOpen_URL_triggered(bool checked);
 
     void on_textInputSearch_textEdited(const QString &text);
 
diff --git a/src/mainwindow.ui b/src/mainwindow.ui
index 292930d..2d7cf30 100644
--- a/src/mainwindow.ui
+++ b/src/mainwindow.ui
@@ -123,6 +123,7 @@ p, li { white-space: pre-wrap; }
      <string>Go</string>
     </property>
     <addaction name="actionRandom_status"/>
+    <addaction name="actionOpen_URL"/>
    </widget>
    <widget class="QMenu" name="menuEdit">
     <property name="title">
@@ -271,6 +272,11 @@ p, li { white-space: pre-wrap; }
     <enum>QAction::PreferencesRole</enum>
    </property>
   </action>
+  <action name="actionOpen_URL">
+   <property name="text">
+    <string>Open URL…</string>
+   </property>
+  </action>
  </widget>
  <tabstops>
   <tabstop>listWidget</tabstop>
diff --git a/src/net/instance.cpp b/src/net/instance.cpp
new file mode 100644
index 0000000..c3af86c
--- /dev/null
+++ b/src/net/instance.cpp
@@ -0,0 +1,24 @@
+#include "instance.h"
+#include "mastodon_instance.h"
+#include "src/settings_interface.h"
+
+Instance* Instance::create_instance() {
+    return create_instance(SettingsInterface::quick_read_setting<AppSettingsTypes::InstanceType>("net/instance/type"));
+}
+
+Instance* Instance::create_instance(AppSettingsTypes::InstanceType type) {
+    switch (type) {
+        case AppSettingsTypes::InstanceType::MASTODON:
+            return new MastodonInstance;
+        default:
+            return nullptr;
+    }
+}
+
+QString Instance::oauth2_step1() {
+    return "";
+}
+
+Instance::OAuth2Step2 Instance::oauth2_step2(const QString &auth_code) {
+    return {false};
+}
diff --git a/src/net/instance.h b/src/net/instance.h
new file mode 100644
index 0000000..2b7eec7
--- /dev/null
+++ b/src/net/instance.h
@@ -0,0 +1,24 @@
+#pragma once
+#include "src/activitypub/appost.h"
+#include "src/settings_interface.h"
+
+class Instance {
+public:
+    struct OAuth2Step2 {
+        bool ok;
+        QString token;
+    };
+
+    virtual ~Instance() {};
+    virtual APPost* get_post_from_url(const QString &url) = 0;
+    // Returns the URI the user has to visit in their browser
+    virtual QString oauth2_step1();
+    // auth_code is the code given by the user through the URI
+    // Returns true if authenfication was successful.
+    virtual OAuth2Step2 oauth2_step2(const QString &auth_code);
+    bool supports_oauth2 = false;
+    // Creates an instance by reading the type from settings
+    static Instance* create_instance();
+    // Creates a specific type of instance, for use with SettingsDialog
+    static Instance* create_instance(AppSettingsTypes::InstanceType type);
+};
diff --git a/src/net/mastodon_instance.cpp b/src/net/mastodon_instance.cpp
new file mode 100644
index 0000000..8b88221
--- /dev/null
+++ b/src/net/mastodon_instance.cpp
@@ -0,0 +1,134 @@
+#include "mastodon_instance.h"
+#include "src/activitypub/appost.h"
+#include "src/activitypub/apquestion.h"
+#include "src/settings_interface.h"
+#include "src/types.h"
+
+#include <QJsonDocument>
+#include <QJsonObject>
+#include <QJsonArray>
+#include <QUrl>
+#include <QDebug>
+
+APPost* post_from_json(const QJsonObject &status);
+
+MastodonInstance::MastodonInstance() : instance(SettingsInterface::quick_read_setting<QString>("net/instance/address").toStdString(), SettingsInterface::quick_read_setting<QString>("net/instance/token").toStdString()), connection(instance) {
+
+}
+
+MastodonInstance::~MastodonInstance() {
+    if (obtain_token)
+        delete obtain_token;
+}
+
+QString MastodonInstance::oauth2_step1() {
+    obtain_token = new mastodonpp::Instance::ObtainToken{instance};
+    auto answer{obtain_token->step_1("ActorViewer", "read", "https://twilightsparkle.space")};
+    if (answer)
+        return answer.body.c_str();
+    else
+        return "";
+}
+
+Instance::OAuth2Step2 MastodonInstance::oauth2_step2(const QString &auth_code) {
+    if (!obtain_token) return {false};
+    auto answer{obtain_token->step_2(auth_code.toStdString())};
+    QString token;
+
+    if (answer) {
+        token = answer.body.c_str();
+    }
+
+    delete obtain_token; obtain_token = nullptr;
+    return {(bool)answer, token};
+}
+
+APPost* MastodonInstance::get_post_from_url(const QString &url) {
+    auto answer{connection.get(mastodonpp::API::v2::search, {
+        {"q", QUrl::toPercentEncoding(url).toStdString()},
+        {"type", "statuses"},
+        {"limit", "1"},
+        {"resolve", "true"}
+    })};
+
+    if (answer) {
+        QJsonDocument doc = QJsonDocument::fromJson(answer.body.c_str());
+        QJsonObject obj = doc.object();
+        qDebug() << doc;
+        if (obj.contains("statuses")) {
+            QJsonObject status = obj["statuses"].toArray().first().toObject();
+            if (status.isEmpty()) return new APPost({.content="invalid"}); // Invalid
+            return post_from_json(status);
+        }
+    }
+
+    return new APPost({.content="connection error"});
+}
+
+// Create a filled APPost object from a Status entity (https://docs.joinmastodon.org/entities/Status/)
+// We have to return a pointer as else I can't get derived classes of APPost to render properly: the additional methods are ignored.
+// Furthermore, using pointers removes unecessary copying, even if that can be reduced by return value optimization.
+APPost* post_from_json(const QJsonObject &status) {
+    APObjectFields fields;
+    bool is_question = status.contains("poll");
+
+    fields.by_actor = status["account"]["url"].toString();
+    fields.reply_to_url = status["in_reply_to_id"].toString(); // id ≠ url
+
+    fields.languages.append(status["language"].toString());
+    fields.published = status["created_at"].toString();
+
+    fields.object_url = status["uri"].toString();
+    fields.web_url = status["url"].toString();
+
+    if (status["sensitive"].toBool(true))
+        fields.summary = status["spoiler_text"].toString();
+    if (status.contains("content"))
+        fields.content = status["content"].toString();
+
+    if (status.contains("visibility")) {
+        QString visibility = status["visibility"].toString();
+        if (visibility == "public") fields.visibility = StatusType::PUBLIC;
+        else if (visibility == "unlisted") fields.visibility = StatusType::UNLISTED;
+        else if (visibility == "private") fields.visibility = StatusType::PRIVATE;
+        else if (visibility == "direct") fields.visibility = StatusType::DIRECT;
+        else fields.visibility = StatusType::UNKNOWN;
+    }
+
+    if (QJsonArray medias = status["media_attachments"].toArray(); not medias.isEmpty()) {
+        for (QJsonValueRef media : medias) {
+            if (not media.isObject()) continue;
+            QJsonObject attrib = media.toObject();
+            fields.attachments.push_back({
+                // FIXME: we use the preview to lower bandwidth but it would be nicer to have APAttachment fields for differencing between qualities.
+                .path = attrib["preview_url"].toString(),
+                // FIXME: we don't have any better attribute to work with
+                .filename = attrib["id"].toString(),
+                .media_type = attrib["type"].toString(),
+                .name = attrib["description"].toString()
+                // TODO: we don't use the blurhash yet…
+            });
+        }
+    }
+
+    if (is_question) {
+        QJsonObject poll = status["poll"].toObject();
+
+        fields.question.end_time = poll["expires_at"].toString();
+        fields.question.closed_time = poll["expires_at"].toString();
+        fields.question.total_votes = poll["votes_count"].toInt();
+
+        for (QJsonValueRef option : poll["options"].toArray()) {
+            QJsonObject element = option.toObject();
+            fields.question.poll_options.push_back({element["title"].toString(), element["votes_count"].toInt()});
+        }
+
+
+        // TODO: have an boolean attribute for defining if the poll is multiple choice or not, int for the voters_count and bool/int for `voted` and `own_votes`
+    }
+
+    if (is_question)
+        return new APQuestion(fields);
+    else
+        return new APPost(fields);
+}
diff --git a/src/net/mastodon_instance.h b/src/net/mastodon_instance.h
new file mode 100644
index 0000000..983bef6
--- /dev/null
+++ b/src/net/mastodon_instance.h
@@ -0,0 +1,19 @@
+#pragma once
+#include "instance.h"
+#include "mastodonpp/instance.hpp"
+#include "mastodonpp/connection.hpp"
+
+class MastodonInstance : public Instance {
+public:
+    MastodonInstance();
+    ~MastodonInstance();
+    APPost* get_post_from_url(const QString &url);
+    QString oauth2_step1();
+    OAuth2Step2 oauth2_step2(const QString &auth_code);
+    bool supports_oauth2 = true;
+
+private:
+    mastodonpp::Instance instance;
+    mastodonpp::Connection connection;
+    mastodonpp::Instance::ObtainToken* obtain_token = nullptr;
+};
diff --git a/src/settingsdialog.cpp b/src/settingsdialog.cpp
index 213859a..051091f 100644
--- a/src/settingsdialog.cpp
+++ b/src/settingsdialog.cpp
@@ -1,6 +1,14 @@
 #include "settingsdialog.h"
+#include "src/net/instance.h"
+#include "src/settings_interface.h"
+
 #include <QPushButton>
 #include <QDialogButtonBox>
+#include <QDesktopServices>
+#include <QUrl>
+#include <QMessageBox>
+#include <QInputDialog>
+#include <qnamespace.h>
 
 SettingsDialog::SettingsDialog(QWidget* parent)
     : QDialog(parent, Qt::Dialog), ui(new Ui::SettingsDialog)
@@ -64,7 +72,24 @@ void SettingsDialog::on_instanceActionsLabel_linkActivated(const QString& link)
         ui->instanceAddressLineEdit->setText(instance_address);
         update_ui_in_progress = false;
     } else if (link == "action:request-token") {
-        // TODO: open browser with token request URL
+        Instance* instance = Instance::create_instance((AppSettingsTypes::InstanceType)ui->instanceTypeComboBox->currentIndex());
+
+        QString url = instance->oauth2_step1();
+        if (not QDesktopServices::openUrl(url))
+            QMessageBox::information(this, tr("Navigate to this URL"), tr("Please open the following URL in your browser: %1").arg(1));
+
+        Instance::OAuth2Step2 step2 = {.ok = false};
+        while (not step2.ok) {
+            bool ok;
+            QString code = QInputDialog::getText(this, tr("Enter authorization code"), tr("Enter the code given during the authentification flow:"), QLineEdit::Normal, "", &ok);
+
+            if (code.isEmpty()) return; // User canceled
+            if (ok) step2 = instance->oauth2_step2(code);
+        }
+
+        // Do not set update_ui_in_progress as we want the new text to be seen as new text by settings_interface (through on_tokenLineEdit_editingFinished())
+        ui->tokenLineEdit->setText(step2.token);
+        on_tokenLineEdit_editingFinished(); // Make sure that the change has been noticed as sometimes it isn't
     }
 }