1 files changed, 105 insertions, 0 deletions
diff --git a/ext/js/extension/environment.js b/ext/js/extension/environment.js
new file mode 100644
index 00000000..d9ca502c
--- /dev/null
+++ b/ext/js/extension/environment.js
@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2020-2022  Yomichan Authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+class Environment {
+    constructor() {
+        this._cachedEnvironmentInfo = null;
+    }
+
+    async prepare() {
+        this._cachedEnvironmentInfo = await this._loadEnvironmentInfo();
+    }
+
+    getInfo() {
+        if (this._cachedEnvironmentInfo === null) { throw new Error('Not prepared'); }
+        return this._cachedEnvironmentInfo;
+    }
+
+    async _loadEnvironmentInfo() {
+        const browser = await this._getBrowser();
+        const os = await this._getOperatingSystem();
+        return {
+            browser,
+            platform: {os}
+        };
+    }
+
+    async _getOperatingSystem() {
+        try {
+            const {os} = await this._getPlatformInfo();
+            if (typeof os === 'string') {
+                return os;
+            }
+        } catch (e) {
+            // NOP
+        }
+        return 'unknown';
+    }
+
+    _getPlatformInfo() {
+        return new Promise((resolve, reject) => {
+            chrome.runtime.getPlatformInfo((result) => {
+                const error = chrome.runtime.lastError;
+                if (error) {
+                    reject(error);
+                } else {
+                    resolve(result);
+                }
+            });
+        });
+    }
+
+    async _getBrowser() {
+        try {
+            if (chrome.runtime.getURL('/').startsWith('ms-browser-extension://')) {
+                return 'edge-legacy';
+            }
+            if (/\bEdge?\//.test(navigator.userAgent)) {
+                return 'edge';
+            }
+        } catch (e) {
+            // NOP
+        }
+        if (typeof browser !== 'undefined') {
+            try {
+                const info = await browser.runtime.getBrowserInfo();
+                if (info.name === 'Fennec') {
+                    return 'firefox-mobile';
+                }
+            } catch (e) {
+                // NOP
+            }
+            if (this._isSafari()) {
+                return 'safari';
+            }
+            return 'firefox';
+        } else {
+            return 'chrome';
+        }
+    }
+
+    _isSafari() {
+        const {vendor, userAgent} = navigator;
+        return (
+            typeof vendor === 'string' &&
+            typeof userAgent === 'string' &&
+            vendor.includes('Apple') &&
+            !userAgent.includes('CriOS') &&
+            !userAgent.includes('FxiOS')
+        );
+    }
+}