Better mod download and error display (#4396)

* Better mod download and error display

* Fix Android Studio Insubordinations

core/src/com/unciv/ui/newgamescreen/ModCheckboxTable.kt

@@ -2,6 +2,7 @@ package com.unciv.ui.newgamescreen
 
 import com.badlogic.gdx.scenes.scene2d.ui.CheckBox
 import com.badlogic.gdx.scenes.scene2d.ui.Table
+import com.unciv.models.ruleset.Ruleset
 import com.unciv.models.ruleset.Ruleset.CheckModLinksResult
 import com.unciv.models.ruleset.RulesetCache
 import com.unciv.models.translations.tr
@@ -39,21 +40,19 @@ class ModCheckboxTable(val mods:LinkedHashSet<String>, val screen: CameraStageBa
                                 mods.remove(oldBaseRuleset)
                     mods.add(mod.name)
 
-                    var isCompatibleWithCurrentRuleset = true
                     var complexModLinkCheck = CheckModLinksResult()
                     try {
                         val newRuleset = RulesetCache.getComplexRuleset(mods)
                         newRuleset.modOptions.isBaseRuleset = true // This is so the checkModLinks finds all connections
                         complexModLinkCheck = newRuleset.checkModLinks()
-                        isCompatibleWithCurrentRuleset = !complexModLinkCheck.isError()
-                    } catch (x: Exception) {
+                    } catch (ex: Exception) {
                         // This happens if a building is dependent on a tech not in the base ruleset
                         //  because newRuleset.updateBuildingCosts() in getComplexRuleset() throws an error
-                        isCompatibleWithCurrentRuleset = false
+                        complexModLinkCheck = CheckModLinksResult(Ruleset.CheckModLinksStatus.Error, ex.localizedMessage)
                     }
 
-                    if (!isCompatibleWithCurrentRuleset) {
-                        ToastPopup("The mod you selected is incompatible with the defined ruleset!\n\n$complexModLinkCheck", screen)
+                    if (complexModLinkCheck.isError()) {
+                        ToastPopup("{The mod you selected is incompatible with the defined ruleset!}\n\n{$complexModLinkCheck}", screen)
                         checkBox.isChecked = false
                         mods.clear()
                         mods.addAll(previousMods)

core/src/com/unciv/ui/pickerscreens/ModManagementScreen.kt

@@ -317,13 +317,14 @@ class ModManagementScreen: PickerScreen(disableScroll = true) {
         val downloadButton = "Download mod from URL".toTextButton()
         downloadButton.onClick {
             val popup = Popup(this)
+            popup.addGoodSizedLabel("Please enter the mod repository -or- archive zip url:").row()
             val textArea = TextArea("https://github.com/...", skin)
             popup.add(textArea).width(stage.width / 2).row()
             val actualDownloadButton = "Download".toTextButton()
             actualDownloadButton.onClick {
                 actualDownloadButton.setText("Downloading...".tr())
                 actualDownloadButton.disable()
-                downloadMod(Github.Repo().apply { html_url = textArea.text; default_branch = "master" }) { popup.close() }
+                downloadMod(Github.Repo().parseUrl(textArea.text)) { popup.close() }
             }
             popup.add(actualDownloadButton).row()
             popup.addCloseButton()
@@ -354,13 +355,13 @@ class ModManagementScreen: PickerScreen(disableScroll = true) {
         addModInfoToActionTable(repo)
     }
 
-    /** Download and install a mod in the background, called from the right-bottom button */
+    /** Download and install a mod in the background, called both from the right-bottom button and the URL entry popup */
     private fun downloadMod(repo: Github.Repo, postAction: () -> Unit = {}) {
         thread(name="DownloadMod") { // to avoid ANRs - we've learnt our lesson from previous download-related actions
             try {
                 val modFolder = Github.downloadAndExtract(repo.html_url, repo.default_branch,
                     Gdx.files.local("mods"))
-                    ?: return@thread
+                    ?: throw Exception()    // downloadAndExtract returns null for 404 errors and the like -> display something!
                 rewriteModOptions(repo, modFolder)
                 Gdx.app.postRunnable {
                     ToastPopup("Downloaded!", this)

core/src/com/unciv/ui/worldscreen/mainmenu/GitHub.kt

@@ -57,7 +57,7 @@ object Github {
         defaultBranch: String,
         folderFileHandle: FileHandle
     ): FileHandle? {
-        // Initiate download - the helper returns null when it fails 
+        // Initiate download - the helper returns null when it fails
         val zipUrl = "$gitRepoUrl/archive/$defaultBranch.zip"
         val inputStream = download(zipUrl) ?: return null
 
@@ -247,6 +247,38 @@ object Github {
         //var stargazers_url = ""
         //var homepage: String? = null      // might use instead of go to repo?
         //var has_wiki = false              // a wiki could mean proper documentation for the mod?
+
+        /**
+         * Initialize `this` with an url, extracting all possible fields from it.
+         *
+         * Allows basic repo url or complete 'zip' url from github's code->download zip menu
+         *
+         * @return `this` to allow chaining
+         */
+        fun parseUrl(url: String): Repo {
+            // Allow url formats
+            //  https://github.com/author/repoName
+            // or
+            //  https://github.com/author/repoName/archive/refs/heads/branchName.zip
+            // and extract author, repoName, branchName
+
+            html_url = url
+            default_branch = "master"
+            val matchZip = Regex("""^(.*/(.*)/(.*))/archive/(?:.*/)?([^.]+).zip$""").matchEntire(url)
+            if (matchZip != null && matchZip.groups.size > 3) {
+                html_url = matchZip.groups[1]!!.value
+                owner.login = matchZip.groups[2]!!.value
+                name = matchZip.groups[3]!!.value
+                default_branch = matchZip.groups[4]!!.value
+            } else {
+                val matchRepo = Regex("""^.*/(.*)/(.*)/?$""").matchEntire(url)
+                if (matchRepo != null && matchRepo.groups.size > 2) {
+                    owner.login = matchRepo.groups[1]!!.value
+                    name = matchRepo.groups[2]!!.value
+                }
+            }
+            return this
+        }
     }
 
     /** Part of [Repo] in Github API response */