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app/src/main/java/dev/equwal/inkupdate/Decide.kt (7196 bytes)

 // SPDX-License-Identifier: GPL-3.0-or-later
 // Copyright (c) 2026 equwal
 package dev.equwal.inkupdate
 
 import org.json.JSONArray
 import org.json.JSONObject
 
 /** What F-Droid said about one app. */
 sealed class FdroidAnswer {
 
     /** F-Droid does not have the app. */
     object NotThere : FdroidAnswer()
 
     /** F-Droid has the app. [page] is the page for a person to open. */
     data class Found(
         val versionCode: Long,
         val versionName: String,
         val page: String
     ) : FdroidAnswer()
 
     /** The request failed, or the answer made no sense. */
     data class Failed(val reason: String) : FdroidAnswer()
 }
 
 /** What GitHub said about one repository. */
 sealed class GithubAnswer {
 
     /** The repository has no release that a person can get. */
     object None : GithubAnswer()
 
     /**
      * The newest release that is not a draft. Every release of these
      * repositories is a pre-release, so the app must not use /releases/latest.
      */
     data class Found(
         val tag: String,
         val page: String,
         val apk: String?
     ) : GithubAnswer()
 
     /** The request failed, or the answer made no sense. */
     data class Failed(val reason: String) : GithubAnswer()
 }
 
 /** What the app knows about one watched app after a check. */
 sealed class Result {
 
     /** The installed version is the newest one found. */
     object UpToDate : Result()
 
     /** A newer version is there. [page] opens it, [apk] downloads it. */
     data class Update(
         val source: String,
         val versionName: String,
         val page: String,
         val apk: String?
     ) : Result()
 
     /** The Play store installed the app, so the Play store updates it. */
     object LeftToPlay : Result()
 
     /** Nobody answered. */
     data class Unknown(val reason: String) : Result()
 }
 
 /**
  * The order of the search, and the reading of the two answers.
  *
  * Nothing here touches Android, so the unit tests run on the JVM.
  */
 object Decide {
 
     const val FDROID = "F-Droid"
     const val GITHUB = "GitHub"
     const val PLAY = "Google Play"
 
     /** The package name of the Play store client. */
     const val PLAY_PACKAGE = "com.android.vending"
 
     /**
      * Where the update comes from. The order is F-Droid, Google Play, GitHub.
      *
      * 1. F-Droid holds a newer build: take it. The F-Droid client updates the
      *    app by itself after the person opens the page once.
      * 2. The Play store installed the app: the Play store updates it. Stop.
      * 3. GitHub holds a newer release: take it.
      *
      * @param installer the package that installed the app, from the system.
      */
     fun source(
         installer: String?,
         fdroid: FdroidAnswer,
         github: GithubAnswer,
         installedCode: Long,
         installedName: String
     ): Result {
         if (fdroid is FdroidAnswer.Found && fdroid.versionCode > installedCode) {
             return Result.Update(FDROID, fdroid.versionName, fdroid.page, null)
         }
         if (installer == PLAY_PACKAGE) return Result.LeftToPlay
 
         if (github is GithubAnswer.Found) {
             val theirs = Version.parse(github.tag)
             val ours = Version.parse(installedName)
             if (theirs == null || ours == null) {
                 return Result.Unknown("Version not understood")
             }
             return if (theirs > ours) {
                 Result.Update(GITHUB, Version.display(github.tag), github.page, github.apk)
             } else {
                 Result.UpToDate
             }
         }
 
         // GitHub gave no release. F-Droid answered, so the app is up to date.
         if (fdroid is FdroidAnswer.Found) return Result.UpToDate
         if (github is GithubAnswer.Failed) return Result.Unknown(github.reason)
         if (fdroid is FdroidAnswer.Failed) return Result.Unknown(fdroid.reason)
 
         // Neither place has the app, so there is nothing newer to get.
         return Result.UpToDate
     }
 
     /**
      * Reads the answer of https://f-droid.org/api/v1/packages/<id>.
      *
      * The answer {"error":"NOT_FOUND"} means that F-Droid does not have the
      * app. That is not a failure.
      *
      * This function never throws.
      */
     fun parseFdroid(body: String?, page: String): FdroidAnswer {
         if (body.isNullOrBlank()) return FdroidAnswer.Failed("Empty answer")
         return try {
             val o = JSONObject(body)
             if (o.has("error")) return FdroidAnswer.NotThere
             if (!o.has("suggestedVersionCode")) return FdroidAnswer.Failed("No version")
             val code = o.getLong("suggestedVersionCode")
             val packages = o.optJSONArray("packages") ?: JSONArray()
             var name = ""
             for (i in 0 until packages.length()) {
                 val p = packages.optJSONObject(i) ?: continue
                 if (p.optLong("versionCode", -1L) == code) {
                     name = p.optString("versionName", "")
                     break
                 }
             }
             if (name.isEmpty() && packages.length() > 0) {
                 name = packages.optJSONObject(0)?.optString("versionName", "") ?: ""
             }
             FdroidAnswer.Found(code, name, page)
         } catch (e: Exception) {
             FdroidAnswer.Failed("Answer not understood")
         }
     }
 
     /**
      * Reads the answer of
      * https://api.github.com/repos/<owner>/<repo>/releases?per_page=10.
      *
      * The first entry that is not a draft wins. A pre-release counts, because
      * every release of these repositories is a pre-release.
      *
      * @param preferAsset a word in the name of the APK to take first.
      *
      * This function never throws.
      */
     fun parseGithub(body: String?, preferAsset: String? = null): GithubAnswer {
         if (body.isNullOrBlank()) return GithubAnswer.Failed("Empty answer")
         return try {
             val list = JSONArray(body)
             for (i in 0 until list.length()) {
                 val r = list.optJSONObject(i) ?: continue
                 if (r.optBoolean("draft", false)) continue
                 val tag = r.optString("tag_name", "")
                 if (tag.isEmpty()) return GithubAnswer.Failed("No tag")
                 val page = r.optString("html_url", "")
                 return GithubAnswer.Found(tag, page, apkOf(r, preferAsset))
             }
             GithubAnswer.None
         } catch (e: Exception) {
             GithubAnswer.Failed("Answer not understood")
         }
     }
 
     /** The APK of a release, or null. A name that holds [prefer] wins. */
     private fun apkOf(release: JSONObject, prefer: String?): String? {
         val assets = release.optJSONArray("assets") ?: return null
         var first: String? = null
         for (i in 0 until assets.length()) {
             val a = assets.optJSONObject(i) ?: continue
             val name = a.optString("name", "").lowercase()
             if (!name.endsWith(".apk")) continue
             val url = a.optString("browser_download_url", "")
             if (url.isEmpty()) continue
             if (prefer != null && name.contains(prefer.lowercase())) return url
             if (first == null) first = url
         }
         return first
     }
 }