6 files changed, 307 insertions, 0 deletions
diff --git a/apply/__init__.py b/apply/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/apply/__init__.py
diff --git a/apply/__main__.py b/apply/__main__.py
new file mode 100644
index 0000000..0612cdf
--- /dev/null
+++ b/apply/__main__.py
@@ -0,0 +1,44 @@
+import argparse
+import yaml
+
+from . import apply as apply_cmd
+
+
+def parse_config(path):
+    config = {}
+    with open(path, "r") as f:
+        config = yaml.safe_load(f)
+
+    return config
+
+
+sub_cmds = {"apply": apply_cmd}
+
+parser = argparse.ArgumentParser()
+parser.add_argument("--apply-dir", "-a", default=None,
+                    help="Directory to load dots from")
+parser.add_argument("--dry-run", "-n", default=False,
+                    help="Do not make filesystem changes",
+                    action="store_true")
+parser.add_argument("--override-existing", "-o", default=False,
+                    help="Override existing files,dirs,links",
+                    action="store_true")
+
+
+sub_parsers = parser.add_subparsers(dest="cmd", help="Action")
+for name, cmd in sub_cmds.items():
+    sub = sub_parsers.add_parser(name, help=cmd.cmd_help)
+    cmd.cmd_args(sub)
+
+args = parser.parse_args()
+
+if args.apply_dir is None:
+    args.apply_dir = ".."
+else:
+    args.apply_dir = str(args.apply_dir)
+
+if args.cmd in sub_cmds:
+    config = parse_config("config.yaml")
+    sub_cmds[args.cmd].cmd_func(args, config)
+else:
+    parser.print_usage()
diff --git a/apply/apply.py b/apply/apply.py
new file mode 100755
index 0000000..8042a1d
--- /dev/null
+++ b/apply/apply.py
@@ -0,0 +1,58 @@
+#!/usr/bin/env python3
+
+import yaml
+import os
+from pathlib import Path
+import argparse
+
+from .resolv import Resolver
+from .writer import Writer
+from .state import StateFile
+
+
+class DirReader:
+    def __init__(self, config, resolv):
+        self.resolv = resolv
+        self.config = config
+
+    def read_package(self, name):
+        package_root = name
+
+        # Walk down and link dir og file
+        for root, dirs, files in os.walk(package_root):
+            rootrel = os.path.relpath(root, start=package_root)
+
+            # Check if we can just link this folder
+            if rootrel not in self.config["do_not_link"]:
+                ok = self.resolv.do_folder_link(name, Path(rootrel))
+
+                if ok:
+                    # Do not go further down
+                    dirs.clear()
+                    continue
+
+            # Link files
+            for f in files:
+                self.resolv.do_link(name, Path(rootrel, f))
+
+
+def cmd_args(parser: argparse.ArgumentParser):
+    parser.add_argument("packages", nargs="*", help="Packages to apply")
+
+
+def cmd_func(args, config):
+    writer = Writer()
+    state = StateFile(args.apply_dir)
+    resolv = Resolver(args.apply_dir, writer, state,
+                      args.override_existing)
+
+    reader = DirReader(config, resolv)
+    for pack in args.packages:
+        reader.read_package(pack)
+
+    writer.apply(dry_run=args.dry_run)
+    if not args.dry_run:
+        state.dump_state()
+
+
+cmd_help = "Apply modules from current directory"
diff --git a/apply/resolv.py b/apply/resolv.py
new file mode 100644
index 0000000..eba5ed1
--- /dev/null
+++ b/apply/resolv.py
@@ -0,0 +1,71 @@
+from pathlib import Path
+from .writer import Writer
+from .state import StateFile, FileState
+import os
+
+
+class Resolver:
+    def __init__(self,
+                 applydir,
+                 writer: Writer,
+                 state: StateFile,
+                 override: bool):
+
+        self.applydir = Path(applydir)
+        self.writer = writer
+        self.override = override
+        self.state = state
+
+    def check_location(self, path: Path) -> FileState:
+        if not path.exists():
+            return FileState.Unused
+
+        if path.is_symlink():
+            dest = Path(os.path.realpath(str(path)))
+            if Path.cwd() in dest.parents:
+                return FileState.create_owned(dest)
+
+        return FileState.Used
+
+    def check_parent(self, path: Path, packagename):
+        """
+        Check if parents exists, and if we created them mark them
+        with package name
+        """
+
+        parent = path.parent
+        exists = parent.exists()
+        if (not exists) or parent in self.state.dirs:
+            self.check_parent(parent, packagename)
+
+            # Add to state
+            self.state.add_dir(parent, packagename)
+
+            if not exists:
+                self.writer.create_dir(parent)
+
+    def do_link(self, package, ppath: Path):
+        dest = Path(self.applydir, ppath)
+        dest_state = self.check_location(dest)
+
+        if not self.override and not dest_state.can_write():
+            # Check if it's a pointer to the correct location
+            raise Exception(f"Destination {ppath} already exists")
+
+        # Save the link in the statefile
+        self.state.add_link(dest, package)
+
+        self.check_parent(dest, package)
+
+        target_abs = Path.cwd().joinpath(Path(package, ppath))
+        if dest_state == FileState.Owned \
+                and dest_state.links_to() == target_abs:
+            return
+
+        if dest_state != FileState.Unused and self.override:
+            self.writer.delete(dest)
+        self.writer.create_link(target_abs, dest)
+
+    def do_folder_link(self, package, ppath: Path) -> bool:
+        self.do_link(package, ppath)
+        return True
diff --git a/apply/state.py b/apply/state.py
new file mode 100644
index 0000000..0bae459
--- /dev/null
+++ b/apply/state.py
@@ -0,0 +1,77 @@
+from pathlib import Path
+import json
+from enum import Enum
+import hashlib
+
+
+def add_or_create(dictio, key, value):
+    if key in dictio:
+        if value not in dictio[key]:
+            dictio[key].append(value)
+    else:
+        dictio[key] = [value]
+
+
+class FileState(Enum):
+    Unused = 1
+    Owned = 2
+    Used = 3
+    links_to_path: Path = Path()
+
+    def can_write(self) -> bool:
+        return self in [FileState.Unused, FileState.Owned]
+
+    def links_to(self) -> str:
+        if self is not FileState.Owned:
+            raise Exception(f"Cannot call location on {self}")
+
+        return self.links_to_path
+
+    @staticmethod
+    def create_owned(links_to: Path) -> "FileState":
+        s = FileState.Owned
+        s.links_to_path = links_to
+        return s
+
+
+class StateFile:
+    links = {}
+    dirs = {}
+    attr_to_save = ["links", "applydir", "dirs"]
+
+    def __init__(self, applydir):
+        # Generate unique string for each possible applydir
+        ustr = hashlib.md5(applydir.encode("utf-8")).hexdigest()[10:]
+        self.applydir = str(applydir)
+
+        self.statefile = Path(f"state_{ustr}.json")
+        if self.statefile.exists():
+            with self.statefile.open("r") as f:
+                self.set_from_dict(json.load(f))
+        else:
+            self.set_from_dict({})
+
+        self.stateclean = True
+
+    def set_from_dict(self, state):
+        self.links = state.get("links", {})
+        self.dirs = state.get("dirs", {})
+        self.applydir = state.get("applydir", self.applydir)
+
+    def save_to_dict(self):
+        all_attr = self.__dict__
+        res = {}
+        for key in self.attr_to_save:
+            res[key] = all_attr[key]
+        return res
+
+    def dump_state(self):
+        with self.statefile.open("w") as f:
+            json.dump(self.save_to_dict(), f)
+
+    def add_dir(self, path: Path, packagename: str):
+        # Add to state
+        add_or_create(self.dirs, str(path), packagename)
+
+    def add_link(self, dest, packagename):
+        self.links[str(dest)] = packagename
diff --git a/apply/writer.py b/apply/writer.py
new file mode 100644
index 0000000..d6a5550
--- /dev/null
+++ b/apply/writer.py
@@ -0,0 +1,57 @@
+import shutil
+from pathlib import Path
+
+
+class Writer:
+    def __init__(self):
+        self.links_todo = {}
+        self.dirs_todo = []
+        self.delete_todo = []
+
+    def create_link(self, target: Path, linkpath: Path):
+        if linkpath in self.links_todo:
+            prev = self.links_todo[linkpath]
+            print(f"Link {linkpath} to {target} replaces previus {prev}")
+        self.links_todo[linkpath] = target
+
+    def create_dir(self, path: Path):
+        if path in self.dirs_todo:
+            return
+
+        self.dirs_todo.append(path)
+
+    def delete(self, path: Path):
+        if path in self.delete_todo:
+            return
+
+        self.delete_todo.append(path)
+
+    def apply_dir(self, path: Path, dry_run):
+        print(f"mkdir {path}")
+        if not dry_run:
+            path.mkdir()
+
+    def apply_delete(self, path: Path, dry_run):
+        if path.is_dir():
+            print(f"rmtree {path}!!!")
+            if not dry_run:
+                shutil.rmtree(str(path))
+        else:
+            print(f"remove {path}")
+            if not dry_run:
+                path.unlink()
+
+    def apply_link(self, linkpath: Path, target: Path, dry_run):
+        print(f"link {linkpath} -> {target}")
+        if not dry_run:
+            linkpath.symlink_to(target)
+
+    def apply(self, dry_run=True):
+        for d in self.delete_todo:
+            self.apply_delete(d, dry_run)
+
+        for d in self.dirs_todo:
+            self.apply_dir(d, dry_run)
+
+        for link, target in self.links_todo.items():
+            self.apply_link(link, target, dry_run)