works, and optimized time for checking the node type

lib/collapsableEmailsAndroid.dart

@@ -1,6 +1,9 @@
-import 'structs.dart';
 import 'package:flutter/material.dart';
-import 'package:flutter_widget_from_html/flutter_widget_from_html.dart';
+import 'api_service.dart';
+import 'structs.dart';
+import 'package:html2md/html2md.dart' as html2md;
+import 'package:markdown_widget/markdown_widget.dart';
+import 'package:markdown/markdown.dart' as md;
 
 class CollapsableEmails extends StatefulWidget {
   final List<String> thread; // email id's in the form xyz@gmail.com
@@ -20,29 +23,287 @@ class _CollapsableEmailsState extends State<CollapsableEmails> {
   List<String> emailsHTML = []; //html of the emails in the thread
   // build attachments with the forldar name and id
   Set<int> _expandedEmails = {}; //open emails
-  List viewtypeIDs = []; //IDs of the viewtypes, order matters
-  List heightOfViewTypes = []; //the height of each viewtype
   List<SerializableMessage> emailsInThread = [];
   bool _isLoaded = false;
 
+  List<String> hirarchy = ["h1", "h2", "h3", "h4", "h5", "h6", "p"];
+  Map<String, int> hirarchyDict = {
+    "h1": 1,
+    "h2": 2,
+    "h3": 3,
+    "h4": 4,
+    "h5": 6,
+    "h6": 7,
+    "p": 8,
+    "ul": 8,
+    "li": 8,
+  };
+
+  List<String> tagsCollected = [];
+  String markdown = '';
+  List<List<String>> sentinel = [];
+  int level = 0;
+  AugmentTree zoomTreeRoot = AugmentTree();
+  late AugmentTree currentZoomNode;
+  bool zoomOut = false;
+  bool zoomIn = true;
+
   @override
   void initState() {
     super.initState();
-    //html
+    _markdownConverter();
+    _serializableData(widget.threadIDs); // this
+    _markdown2Tree(markdown);
+    _buildForZooms();
   }
 
+  @override
+  void dispose() {
+    super.dispose();
+  }
+
+  void _markdownConverter() async {
+    markdown = html2md.convert(widget.threadHTML[0]);
+  }
+
+  void _add2Tree(AugmentTree tree, md.Element node2add) {
+    // adds node to its corresponding place
+    AugmentTree newNode = AugmentTree();
+    newNode.setData(node2add.textContent);
+    newNode.ogTag = node2add.tag;
+    // cases,
+    //1. a node that comes is lower than the root.children last, if so it goes beneath it
+    if (tree.children.isEmpty) {
+      // new level to be created when totally empty
+      tree.children.add(newNode);
+      newNode.parent = tree;
+    } else if (tree.children.isNotEmpty &&
+        tree.children.last.ogTag.isNotEmpty) {
+      if ((hirarchyDict[node2add.tag] ??
+              -1) < // e.g. new node is h1 and old is h2, heapify
+          (hirarchyDict[tree.children.last.ogTag] ?? -1)) {
+        //have to figure out the borthers
+        //assuming it all goes right
+        if ((hirarchyDict[node2add.tag] ?? -1) == -1 ||
+            (hirarchyDict[tree.children.last.ogTag] ?? -1) == -1) {
+          print(
+              'failed and got -1 at _add2Tree \n ${hirarchyDict[node2add.tag] ?? -1} < ${hirarchyDict[tree.children.last.ogTag] ?? -1}');
+          return;
+        } else if (tree.children.last.parent == null) {
+          // becomes the new top level
+          for (AugmentTree brother in tree.children) {
+            brother.parent = newNode;
+          }
+          tree.children = [newNode];
+        } else {
+          newNode.parent = tree;
+          tree.children.add(newNode);
+        }
+      } else if ((hirarchyDict[node2add.tag] ??
+              -1) > // go down e.g. new node is h3 and old is h2 or something
+          (hirarchyDict[tree.children.last.ogTag] ?? -1)) {
+        if ((hirarchyDict[node2add.tag] ?? -1) == -1 ||
+            (hirarchyDict[tree.children.last.ogTag] ?? -1) == -1) {
+          print(
+              'failed and got -1 at _add2Tree \n ${hirarchyDict[node2add.tag] ?? -1} > ${hirarchyDict[tree.children.last.ogTag] ?? -1}');
+          print("-1 ${tree.children.last.ogTag}");
+          return;
+        }
+
+        _add2Tree(tree.children.last, node2add);
+      } else if ((hirarchyDict[node2add.tag] ?? -1) ==
+          (hirarchyDict[tree.children.last.ogTag] ?? -1)) {
+        tree.children.add(newNode);
+        newNode.parent = tree;
+      }
+    }
+  }
+
+  void _markdown2Tree(String text) {
+    print("started markdown2tree");
+    final List<md.Node> nakedList = md.Document().parseLines(text.split('\n'));
+
+    for (var node in nakedList) {
+      //maybe do an add function, but isn't this it?
+      if (node is md.Element) {
+        // print(node.textContent);
+        AugmentTree temp = AugmentTree();
+        temp.data = node.textContent;
+        temp.ogTag = node.tag;
+        if (hirarchyDict.containsKey(node.tag)) {
+          _add2Tree(zoomTreeRoot, node);
+        }
+      }
+
+      currentZoomNode = zoomTreeRoot;
+      if (!mounted) return;
+      setState(() {
+        _isLoaded = true;
+      });
+    }
+  }
+
+  void _goToChildren(int index) async {
+    final target = currentZoomNode.children[index];
+    if (target.children.isNotEmpty) {
+      setState(() {
+        currentZoomNode = target;
+      });
+    } else {
+      print("This child has no further children.");
+    }
+
+    // if (currentZoomNode.children.isNotEmpty) {
+    //   setState(() {
+    //     zoomIn = true;
+    //     zoomOut = true;
+    //     currentZoomNode = currentZoomNode.children[index];
+    //     if (currentZoomNode.children[index].children.isEmpty) {
+    //       print('disable in');
+    //       setState(() {
+    //         zoomIn = false;
+    //       });
+    //     }
+    //   });
+    // } else {
+    //   print("disable zoom down");
+    //   setState(() {
+    //     zoomIn = false;
+    //   });
+    // }
+  }
+
+  void _goToParent() async {
+    if (currentZoomNode.parent != null) {
+      setState(() {
+        currentZoomNode = currentZoomNode.parent!;
+      });
+    } else {
+      print("Already at root.");
+    }
+
+    // print("parent ${currentZoomNode.parent}");
+    // print("parent ${currentZoomNode.parent!.parent}");
+    // if (currentZoomNode.parent != null) {
+    //   setState(() {
+    //     currentZoomNode = currentZoomNode.parent!;
+    //     if (currentZoomNode.parent == null) {
+    //       setState(() {
+    //         zoomOut = false;
+    //       });
+    //     }
+    //   });
+    // } else if (currentZoomNode.parent == null ||
+    //     currentZoomNode.parent!.parent == null) {
+    //   print("disable zoom up");
+  }
+
+  void _serializableData(String threadID) async {
+    emailsInThread = await ApiService().threadsInSerializable(threadID);
+    print("done thread serializable");
+    if (!mounted) return;
+    setState(() {
+      _isLoaded = true;
+    });
+  }
+
+  Widget _buildForZooms({Key? key}) {
+    if (!_isLoaded) {
+      return const Center(child: CircularProgressIndicator()); // loading screen
+    }
+    final canZoomOut = currentZoomNode.parent != null;
+
+    return ListView.builder(
+      key: key,
+      itemCount: currentZoomNode.children.length,
+      itemBuilder: (context, index) {
+        final childNode = currentZoomNode.children[index];
+        final canZoomIn = childNode.children.isNotEmpty;
+
+        return Padding(
+          padding: const EdgeInsets.symmetric(horizontal: 12.0, vertical: 6.0),
+          child: Material(
+            elevation: 1,
+            borderRadius: BorderRadius.circular(12),
+            color: Theme.of(context).colorScheme.surface,
+            surfaceTintColor: Theme.of(context).colorScheme.surfaceBright,
+            child: Padding(
+              padding: const EdgeInsets.all(16.0),
+              child: Row(
+                crossAxisAlignment: CrossAxisAlignment.start,
+                children: [
+                  Wrap(
+                    spacing: 4.0,
+                    children: [
+                      OutlinedButton(
+                        onPressed: canZoomOut ? () => _goToParent() : null,
+                        child: Icon(Icons.north_west_sharp),
+                      ),
+                      OutlinedButton(
+                        onPressed:
+                            canZoomIn ? () => _goToChildren(index) : null,
+                        child: Icon(Icons.south_east_sharp),
+                      ),
+                    ],
+                  ),
+                  SizedBox(width: 12.0),
+                  Expanded(
+                    child: MarkdownBlock(
+                      data: currentZoomNode
+                          .children[index].data, // one string of markdown
+                      config: MarkdownConfig
+                          .darkConfig, // or lightConfig depending on theme
+                    ),
+                  ),
+                ],
+              ),
+            ),
+          ),
+        );
+      },
+    );
+  }
 
   @override
   Widget build(BuildContext context) {
-    return Scaffold(
+    return _isLoaded
-      body: ListView(
+        ? Column(children: [
+            Expanded(
+              child: ListView.builder(
+                itemCount: emailsInThread.length,
+                itemBuilder: (context, index) {
+                  final isExpanded = _expandedEmails
+                      .contains(index); //check if email is expanded
+                  return Column(
                     children: [
-          HtmlWidget(
+                      ListTile(
-            widget.threadHTML[0],
+                        title: Text(emailsInThread[index].from),
-            // renderMode: RenderMode.listView,
+                        trailing: Text(emailsInThread[index].date),
-          )
+                        onTap: () {
-        ]
+                          setState(() {
-      )
+                            if (isExpanded) {
+                              _expandedEmails.remove(index);
+                            } else {
+                              _expandedEmails.add(index);
+                            }
+                          });
+                        },
+                      ),
+                      if (isExpanded)
+                        ConstrainedBox(
+                            constraints: BoxConstraints(
+                                minHeight: 100,
+                                maxHeight:
+                                    MediaQuery.of(context).size.height * 0.6),
+                            child:
+                                _buildForZooms(key: ValueKey(currentZoomNode))),
+                      Divider(),
+                    ],
                   );
+                },
+              ),
+            ),
+          ])
+        : const Center(child: CircularProgressIndicator());
   }
 }