diff --git a/src/.vscode/settings.json b/.vscode/settings.json
similarity index 100%
rename from src/.vscode/settings.json
rename to .vscode/settings.json
diff --git a/src/baguthesis.py b/src/baguthesis.py
index c249bab..1573192 100644
--- a/src/baguthesis.py
+++ b/src/baguthesis.py
@@ -1,9 +1,20 @@
-import cli.baguthesis
+import tempfile
+from pathlib import Path
+import latex2xthesis
+import xthesis2docx
+from cli.baguthesis import LaTeX2DocxCli, parse_cli
 
 
-def main():
-    args = cli.baguthesis.parse_cli()
+def main(opts: LaTeX2DocxCli):
+    with tempfile.TemporaryDirectory() as temp_dir:
+        # Create a temporary directory and XThesis intermediate file in it
+        temp_dir_path = Path(temp_dir).resolve()
+        temp_xthesis_path = temp_dir_path / "temp.xthesis"
+        # Break the options into frontend and backend options and run them respectively
+        frontend_opts, backend_opts = opts.break_into(temp_xthesis_path)
+        latex2xthesis.main(frontend_opts)
+        xthesis2docx.main(backend_opts)
 
 
 if __name__ == "__main__":
-    main()
+    main(parse_cli())
diff --git a/src/common.py b/src/common.py
new file mode 100644
index 0000000..a7f3b86
--- /dev/null
+++ b/src/common.py
@@ -0,0 +1,54 @@
+from pathlib import Path
+from logger import LOGGER
+
+
+class BaGuException(Exception):
+    """The exception raised by this project."""
+    pass
+
+
+
+def resolve_resource(tobe_resolved: str, resource_dir: Path) -> Path | None:
+    """
+    Resolve given path in resource directory or current work directory.
+
+    This function will use absolute path directly if it is and it is exist.
+    If not, this function will try to resolve it in resource directory first, 
+    and then in current work directory.
+
+    :param tobe_resolved: The path to be resolved.
+    :param resource_dir: The resource directory.
+    :return: The resolved path if resolved, otherwise None.
+    """
+    tobe_resolved_path = Path(tobe_resolved)
+    LOGGER.debug(f'Resolving {tobe_resolved_path} ...')
+
+    # Return absolute path directly
+    if tobe_resolved_path.is_absolute():
+        if tobe_resolved_path.is_file():
+            LOGGER.debug(f'Resolved {tobe_resolved_path}')
+            return tobe_resolved_path
+        else:
+            LOGGER.debug(f'{tobe_resolved_path} is absolute path but not a file.')
+            return None
+
+    # Resolve it in resource directory first
+    resource_dir_path = Path(resource_dir).resolve()
+    resolved = resource_dir_path / tobe_resolved_path
+    if resolved.is_file():
+        LOGGER.debug(f'Resolved {resolved}')
+        return resolved
+    else:
+        LOGGER.debug(f'Resolved failed in resource path because {resolved} is not a file.')
+
+    # Resolve it in work directory
+    cwd_path = Path.cwd().resolve()
+    resolved = cwd_path / tobe_resolved_path
+    if resolved.is_file():
+        LOGGER.debug(f'Resolved {resolved}')
+        return resolved
+    else:
+        LOGGER.debug(f'Resolved failed in current work directory because {resolved} is not a file.')
+
+    # Not resolved
+    return None
diff --git a/src/latex2xthesis.py b/src/latex2xthesis.py
deleted file mode 100644
index d9e312c..0000000
--- a/src/latex2xthesis.py
+++ /dev/null
@@ -1,9 +0,0 @@
-import cli.latex2xthesis
-
-
-def main():
-    args = cli.latex2xthesis.parse_cli()
-
-
-if __name__ == "__main__":
-    main()
diff --git a/src/latex2xthesis/__init__.py b/src/latex2xthesis/__init__.py
new file mode 100644
index 0000000..fd58be5
--- /dev/null
+++ b/src/latex2xthesis/__init__.py
@@ -0,0 +1,74 @@
+from pathlib import Path
+from typing import Iterator
+from pylatexenc import latexwalker
+from cli.latex2xthesis import LaTeX2XThesisCli, parse_cli
+from common import BaGuException
+from logger import LOGGER
+
+
+class LatexWalkerEnvironment:
+
+    __loaded_texs: set[Path]
+    """The set storing all loaded tex files to avoid circular including"""
+
+    def __init__(self) -> None:
+        self.__loaded_texs = set()
+
+    def register_tex_filename(self, filename: Path) -> bool:
+        """
+        Register tex file name as loaded.
+
+        :return: False if this file name is already registered, otherwise true.
+        """
+        if filename in self.__loaded_texs:
+            return False
+        else:
+            self.__loaded_texs.add(filename)
+            return True
+
+
+class LatexWalker:
+    
+    environment: LatexWalkerEnvironment
+    """The environment of this walker"""
+    walker: latexwalker.LatexWalker | None
+    """The underlying walker"""
+
+    def __init__(self, environment: LatexWalkerEnvironment, filename: Path) -> None:
+        # Check environment
+        self.environment = environment
+        
+        # Try to load file.
+        try:
+            with open(filename, 'r') as f:
+                self.walker = latexwalker.LatexWalker(f.read())
+        except Exception as e:
+            LOGGER.warning(f'Fail to read LaTeX file: {filename}. Reason: {e}.')
+            self.walker = None
+
+    def iter(self) -> Iterator[latexwalker.LatexNode]:
+        if self.walker is not None:
+            # get node list
+            nodelists: list[latexwalker.LatexNode]
+            (nodelists, _, _) = self.walker.get_latex_nodes()
+
+            # special treat for command node for inserted document
+            for node in nodelists:
+                if isinstance(node, latexwalker.LatexMacroNode):
+                    node.macroname
+                    pass
+                else:
+                    yield node
+                    
+
+
+
+
+
+
+def main(opts: LaTeX2XThesisCli):
+    pass
+
+
+if __name__ == "__main__":
+    main(parse_cli())
diff --git a/src/latex2xthesis/extractor.py b/src/latex2xthesis/extractor.py
new file mode 100644
index 0000000..e69de29
diff --git a/src/latex2xthesis/latexwalker.py b/src/latex2xthesis/latexwalker.py
new file mode 100644
index 0000000..688ff67
--- /dev/null
+++ b/src/latex2xthesis/latexwalker.py
@@ -0,0 +1,236 @@
+from pathlib import Path
+from abc import ABC, abstractmethod
+from collections.abc import Iterator, Iterable
+from typing import cast
+from pylatexenc.latexwalker import (
+    LatexWalker as PyLatexWalker,
+    LatexNode as PyLatexNode,
+    LatexCommentNode as PyLatexCommentNode,
+    LatexMacroNode as PyLatexMacroNode,
+)
+from ..logger import LOGGER
+
+
+class LatexWalker(Iterator[PyLatexNode]):
+    """
+    The interface of all LaTeX walkers.
+
+    A LaTeX walker is an iterator that iterates over LaTeX nodes.
+    And for the convenience, we also provide a method `peek` to peek the next node without advancing the walker.
+    and an Rust-like iterator interface called `next` to fetch the next node and advance the walker.
+    """
+
+    @abstractmethod
+    def peek(self) -> PyLatexNode | None:
+        """
+        Peek the next node without advancing the walker.
+
+        :return: The next node or None if there is no more node.
+        """
+        pass
+
+    @abstractmethod
+    def next(self) -> PyLatexNode | None:
+        """
+        Fetch the next node and advance the walker.
+
+        :return: The next node or None if there is no more node.
+        """
+        pass
+
+    def __iter__(self) -> Iterator[PyLatexNode]:
+        return self
+
+    def __next__(self) -> PyLatexNode:
+        node = self.next()
+        if node is None:
+            raise StopIteration
+        else:
+            return node
+
+
+class FileLatexWalker(LatexWalker):
+    """
+    A trivial implementation of LaTeX walker which only output LaTeX nodes one by one.
+    """
+
+    walker: PyLatexWalker | None
+    """The underlying walker"""
+    nodelist: list[PyLatexNode]
+    """The list of nodes provided by underlying walker"""
+    cnt: int
+    """The count of all nodes"""
+    i: int
+    """The current index"""
+
+    def __init__(
+        self, walker: PyLatexWalker | None, nodelist: list[PyLatexNode]
+    ) -> None:
+        self.walker = walker
+        self.nodelist = nodelist
+        self.cnt = len(nodelist)
+        self.i = 0
+
+    @staticmethod
+    def from_file(filename: Path) -> "FileLatexWalker":
+        # Try to load file.
+        walker: PyLatexWalker | None
+        try:
+            with open(filename, "r") as f:
+                walker = PyLatexWalker(f.read())
+                (nodelist, _, _) = walker.get_latex_nodes()
+                return FileLatexWalker(walker, nodelist)
+        except Exception as e:
+            LOGGER.warning(f"Fail to read LaTeX file: {filename}. Reason: {e}.")
+            return FileLatexWalker(None, list())
+
+    def peek(self) -> PyLatexNode | None:
+        if self.walker is None:
+            return None
+
+        if self.i >= self.cnt:
+            return None
+        else:
+            return self.nodelist[self.i]
+
+    def next(self) -> PyLatexNode | None:
+        node = self.peek()
+        if node is not None:
+            self.i += 1
+        return node
+
+
+class ResolvingIncludeContext:
+    __loaded_texs: set[Path]
+    """The set storing all loaded tex files to avoid circular including"""
+
+    def __init__(self) -> None:
+        self.__loaded_texs = set()
+
+    def test(self, filename: Path) -> bool:
+        """
+        Register tex file name as loaded.
+
+        :return: False if this file name is already registered, otherwise true.
+        """
+        if filename in self.__loaded_texs:
+            return False
+        else:
+            self.__loaded_texs.add(filename)
+            return True
+
+
+class ResolvingIncludeLatexWalker(LatexWalker):
+    """
+    A LaTeX walker wrapper that can resolve include command.
+    """
+
+    underlying: LatexWalker
+    """The underlying walker"""
+    loaded: LatexWalker | None
+    """The walker loaded by LaTeX include command"""
+    context: ResolvingIncludeContext
+    """The context for resolving include command"""
+
+    def __init__(
+        self, underlying: LatexWalker, context: ResolvingIncludeContext
+    ) -> None:
+        self.underlying = underlying
+        self.loaded = None
+        self.context = context
+
+    # def from_filename(filename: Path) -> 'ResolvingIncludeLatexWalker':
+    #     pass
+
+    # def from_base_tex(walker: LatexWalker) -> 'ResolvingIncludeLatexWalker':
+    #     pass
+
+    # def from_included_tex(walker: LatexWalker, context: ResolvingIncludeContext) -> 'ResolvingIncludeLatexWalker':
+    #     pass
+
+    def peek(self) -> PyLatexNode | None:
+        pass
+
+    def next(self) -> PyLatexNode | None:
+        pass
+
+
+class Condition(ABC):
+    """
+    A condition that can break a LaTeX walker.
+    """
+
+    @abstractmethod
+    def can_break(self, node: PyLatexNode) -> bool:
+        """
+        Check if the given node can trigger the walker to break.
+
+        :param node: The node to check.
+        :return: True if the node can trigger the walker to break, otherwise false.
+        """
+        pass
+
+
+class MultiCommandCondition(Condition):
+    """
+    A condition that can break a LaTeX walker when one of the certain commands is encountered.
+    """
+
+    __commands: set[str]
+    """The set of commands that can trigger the walker to break"""
+
+    def __init__(self, commands: Iterable[str]) -> None:
+        """
+        Initialize the condition with a set of commands.
+
+        :param commands: The commands that can trigger the walker to break.
+        """
+        self.__commands = set(commands)
+
+    def can_break(self, node: PyLatexNode) -> bool:
+        if isinstance(node, PyLatexMacroNode):
+            macro_name = cast(str, node.macroname)
+            return macro_name in self.__commands
+        else:
+            return False
+
+
+class CommentCondition(Condition):
+    """
+    A condition that can break a LaTeX walker when a certain comment is encountered.
+    """
+
+    __comment: str
+    """The comment that can trigger the walker to break"""
+
+    def __init__(self, comment: str) -> None:
+        """
+        Initialize the condition with a comment.
+
+        :param comment: The comment that can trigger the walker to break.
+        """
+        self.__comment = comment
+
+    def can_break(self, node: PyLatexNode) -> bool:
+        if isinstance(node, PyLatexCommentNode):
+            node_comment = cast(str, node.comment)
+            return node_comment == self.__comment
+        else:
+            return False
+
+
+class ConditionalLatexWalker(LatexWalker):
+    """
+    A LaTeX walker wrapper that can break when a certain condition is met.
+
+    The node triggering the break is not consumed by this walker,
+    and can be accessed by the underlying walker.
+    """
+
+    underlying: LatexWalker
+    """The underlying walker"""
+    condition: Condition
+
+    def __init__(self, underlying: LatexWalker, condition: Condition) -> None:
+        self.underlying = underlying
+        self.condition = condition
diff --git a/src/logger.py b/src/logger.py
new file mode 100644
index 0000000..a2ecd69
--- /dev/null
+++ b/src/logger.py
@@ -0,0 +1,42 @@
+import logging
+import enum
+
+
+def _build_logger() -> tuple[logging.Logger, logging.Handler]:
+    # Create a new logger which is independent with Flask
+    logger = logging.getLogger("my_console_logger")
+    # Avoid message was propagated to root logger or captured by Flask logger.
+    logger.propagate = False
+    # Set initial level.
+    logger.setLevel(logging.INFO)
+
+    # Create StreamHandler to output into stderr.
+    console_handler = logging.StreamHandler()
+    console_handler.setLevel(logging.DEBUG)
+    # Set format for it.
+    formatter = logging.Formatter("[%(levelname)s] %(message)s")
+    console_handler.setFormatter(formatter)
+    # Add handler
+    logger.addHandler(console_handler)
+
+    return (logger, console_handler)
+
+
+(LOGGER, CONSOLE_HANDLER) = _build_logger()
+
+
+class LoggerLevel(enum.IntEnum):
+    DEBUG = enum.auto()
+    INFO = enum.auto()
+
+
+def set_level(level: LoggerLevel) -> None:
+    logging_level: int = logging.INFO
+    match level:
+        case LoggerLevel.DEBUG:
+            logging_level = logging.DEBUG
+        case LoggerLevel.INFO:
+            logging_level = logging.INFO
+
+    LOGGER.setLevel(logging_level)
+    CONSOLE_HANDLER.setLevel(logging_level)
diff --git a/src/xthesis2docx.py b/src/xthesis2docx.py
deleted file mode 100644
index a8de4b0..0000000
--- a/src/xthesis2docx.py
+++ /dev/null
@@ -1,9 +0,0 @@
-import cli.xthesis2docx
-
-
-def main():
-    args = cli.xthesis2docx.parse_cli()
-
-
-if __name__ == "__main__":
-    main()
diff --git a/src/xthesis2docx/__init__.py b/src/xthesis2docx/__init__.py
new file mode 100644
index 0000000..953322d
--- /dev/null
+++ b/src/xthesis2docx/__init__.py
@@ -0,0 +1,9 @@
+from cli.xthesis2docx import XThesis2DocxCli, parse_cli
+
+
+def main(opts: XThesis2DocxCli):
+    pass
+
+
+if __name__ == "__main__":
+    main(parse_cli())
diff --git a/src/xthesis2docx/__main__.py b/src/xthesis2docx/__main__.py
new file mode 100644
index 0000000..953322d
--- /dev/null
+++ b/src/xthesis2docx/__main__.py
@@ -0,0 +1,9 @@
+from cli.xthesis2docx import XThesis2DocxCli, parse_cli
+
+
+def main(opts: XThesis2DocxCli):
+    pass
+
+
+if __name__ == "__main__":
+    main(parse_cli())