Add the \todo and \missingfigure commands from the todonotes package to the todo tool window.

resources/META-INF/extensions/index.xml

@@ -17,5 +17,8 @@
         <fileBasedIndex implementation="nl.hannahsten.texifyidea.index.file.LatexExternalEnvironmentIndex" />
         <fileBasedIndex implementation="nl.hannahsten.texifyidea.index.file.LatexExternalPackageInclusionIndex" />
         <indexedRootsProvider implementation="nl.hannahsten.texifyidea.index.file.LatexIndexableSetContributor" />
+        <indexPatternSearch implementation="nl.hannahsten.texifyidea.index.LatexTodoSearcher"/>
+        <indexPatternProvider implementation="nl.hannahsten.texifyidea.index.LatexTodoIndexPatternProvider"/>
+        <todoIndexer filetype="LaTeX source file" implementationClass="nl.hannahsten.texifyidea.index.LatexTodoIndexer"/>
     </extensions>
 </idea-plugin>

src/nl/hannahsten/texifyidea/index/LatexTodoIndexPatternProvider.kt

@@ -0,0 +1,11 @@
+package nl.hannahsten.texifyidea.index
+
+import com.intellij.psi.search.IndexPattern
+import com.intellij.psi.search.IndexPatternProvider
+import nl.hannahsten.texifyidea.util.magic.CommandMagic
+
+class LatexTodoIndexPatternProvider : IndexPatternProvider {
+    override fun getIndexPatterns(): Array<IndexPattern> {
+        return CommandMagic.todoCommands.map { IndexPattern("${it.replace("\\", "\\\\")}\\b", true) }.toTypedArray()
+    }
+}

src/nl/hannahsten/texifyidea/index/LatexTodoIndexer.kt

@@ -0,0 +1,29 @@
+package nl.hannahsten.texifyidea.index
+
+import com.intellij.lexer.Lexer
+import com.intellij.psi.impl.cache.impl.BaseFilterLexer
+import com.intellij.psi.impl.cache.impl.OccurrenceConsumer
+import com.intellij.psi.impl.cache.impl.todo.LexerBasedTodoIndexer
+import nl.hannahsten.texifyidea.grammar.LatexLexerAdapter
+import nl.hannahsten.texifyidea.grammar.LatexTokenSets
+import nl.hannahsten.texifyidea.psi.LatexTypes
+import nl.hannahsten.texifyidea.util.magic.CommandMagic
+
+/**
+ * Counts the "to do" item, so that it shows up in the Project "to do" window and the count of the number of items is correct.
+ */
+class LatexTodoIndexer : LexerBasedTodoIndexer() {
+    override fun createLexer(consumer: OccurrenceConsumer): Lexer {
+        return LatexFilterLexer(consumer)
+    }
+}
+
+class LatexFilterLexer(consumer: OccurrenceConsumer) : BaseFilterLexer(LatexLexerAdapter(), consumer) {
+    override fun advance() {
+        val tokenType = delegate.tokenType
+        if (tokenType in LatexTokenSets.COMMENTS || (tokenType == LatexTypes.COMMAND_TOKEN && delegate.tokenText in CommandMagic.todoCommands)) {
+            advanceTodoItemCountsInToken()
+        }
+        delegate.advance()
+    }
+}

src/nl/hannahsten/texifyidea/index/LatexTodoSearcher.kt

@@ -0,0 +1,36 @@
+package nl.hannahsten.texifyidea.index
+
+import com.intellij.openapi.application.QueryExecutorBase
+import com.intellij.openapi.util.TextRange
+import com.intellij.psi.PsiFile
+import com.intellij.psi.search.IndexPattern
+import com.intellij.psi.search.IndexPatternOccurrence
+import com.intellij.psi.search.searches.IndexPatternSearch
+import com.intellij.util.Processor
+import nl.hannahsten.texifyidea.file.LatexFile
+import nl.hannahsten.texifyidea.util.files.commandsInFile
+import nl.hannahsten.texifyidea.util.magic.CommandMagic
+import nl.hannahsten.texifyidea.util.matches
+
+/**
+ * Provides the "to do" item in the toolwindow and highlighting in the editor.
+ */
+@Suppress("UnstableApiUsage")
+class LatexTodoSearcher : QueryExecutorBase<IndexPatternOccurrence, IndexPatternSearch.SearchParameters>() {
+    override fun processQuery(queryParameters: IndexPatternSearch.SearchParameters, consumer: Processor<in IndexPatternOccurrence>) {
+        val file = queryParameters.file as? LatexFile ?: return
+
+        queryParameters.patternProvider.indexPatterns.forEach { pattern ->
+            file.commandsInFile().filter { it.name in CommandMagic.todoCommands }.filter { pattern.pattern?.matches(it.name) == true }
+                .forEach {
+                    consumer.process(LatexTodoOccurrence(file, it.textRange, pattern))
+                }
+        }
+    }
+}
+
+private data class LatexTodoOccurrence(private val file: LatexFile, private val textRange: TextRange, private val pattern: IndexPattern) : IndexPatternOccurrence {
+    override fun getFile(): PsiFile = file
+    override fun getTextRange(): TextRange = textRange
+    override fun getPattern(): IndexPattern = pattern
+}

src/nl/hannahsten/texifyidea/lang/LatexPackage.kt

@@ -86,6 +86,7 @@ open class LatexPackage @JvmOverloads constructor(
         val TCOLORBOX = LatexPackage("tcolorbox")
         val TEXTCOMP = LatexPackage("textcomp")
         val TIKZ = LatexPackage("tikz")
+        val TODONOTES = LatexPackage("todonotes")
         val ULEM = LatexPackage("ulem")
         val VARIOREF = LatexPackage("varioref")
         val WASYSYM = LatexPackage("wasysym")

src/nl/hannahsten/texifyidea/lang/commands/LatexRegularCommand.kt

@@ -25,9 +25,10 @@ object LatexRegularCommand {
     private val LISTINGS: Set<LatexCommand> = LatexListingCommand.entries.toSet()
     private val LOREM_IPSUM: Set<LatexCommand> = LatexLoremIpsumCommand.entries.toSet()
     private val GLOSSARY: Set<LatexCommand> = LatexGlossariesCommand.entries.toSet()
+    private val TODO: Set<LatexCommand> = LatexTodoCommand.entries.toSet()
 
     val ALL: Set<LatexCommand> = GENERIC + TEXTCOMP + EURO + TEXT_SYMBOLS + NEW_DEFINITIONS + MATHTOOLS +
-        XCOLOR + XPARSE + NATBIB + BIBLATEX + SIUNITX + ALGORITHMICX + IFS + LISTINGS + LOREM_IPSUM + GLOSSARY
+        XCOLOR + XPARSE + NATBIB + BIBLATEX + SIUNITX + ALGORITHMICX + IFS + LISTINGS + LOREM_IPSUM + GLOSSARY + TODO
 
     private val lookup = HashMap<String, NonEmptySet<LatexCommand>>()
     private val lookupDisplay = HashMap<String, NonEmptySet<LatexCommand>>()

src/nl/hannahsten/texifyidea/lang/commands/LatexTodoCommand.kt

@@ -0,0 +1,22 @@
+package nl.hannahsten.texifyidea.lang.commands
+
+import nl.hannahsten.texifyidea.lang.LatexPackage
+import nl.hannahsten.texifyidea.lang.LatexPackage.Companion.TODONOTES
+
+enum class LatexTodoCommand(
+    override val command: String,
+    override vararg val arguments: Argument = emptyArray(),
+    override val dependency: LatexPackage = LatexPackage.DEFAULT,
+    override val display: String? = null,
+    override val isMathMode: Boolean = false,
+    val collapse: Boolean = false
+) : LatexCommand {
+
+    TODO("todo", "note".asRequired(), dependency = TODONOTES),
+    MISSINGFIGURE("missingfigure", "note".asRequired(), dependency = TODONOTES),
+    LISTOFTODOS("listoftodos", "name".asOptional(), dependency = TODONOTES)
+    ;
+
+    override val identifier: String
+        get() = name
+}

src/nl/hannahsten/texifyidea/util/magic/CommandMagic.kt

@@ -17,6 +17,7 @@ import nl.hannahsten.texifyidea.lang.commands.LatexNatbibCommand.*
 import nl.hannahsten.texifyidea.lang.commands.LatexNewDefinitionCommand.*
 import nl.hannahsten.texifyidea.lang.commands.LatexOperatorCommand.*
 import nl.hannahsten.texifyidea.lang.commands.LatexRegularCommand
+import nl.hannahsten.texifyidea.lang.commands.LatexTodoCommand
 import nl.hannahsten.texifyidea.lang.commands.LatexUncategorizedStmaryrdSymbols.BIG_SQUARE_CAP
 import nl.hannahsten.texifyidea.lang.commands.LatexXparseCommand.*
 
@@ -499,4 +500,9 @@ object CommandMagic {
     val foldableFootnotes = listOf(
         FOOTNOTE.cmd, FOOTCITE.cmd
     )
+
+    /**
+     * Commands that should be contributed to the to do toolwindow.
+     */
+    val todoCommands = setOf(LatexTodoCommand.TODO.cmd, LatexTodoCommand.MISSINGFIGURE.cmd)
 }