From d4a7b7542c59df7941350b72935c3aad9bfc94e9 Mon Sep 17 00:00:00 2001
From: Andreas Gebhardt <agebhar1@googlemail.com>
Date: Fri, 1 Sep 2023 20:32:12 +0200
Subject: [PATCH] [WIP]

---
 graph/planner/planner.py       | 92 ++++++++++++++++++++++++++++++++++
 graph/planner/planner_test.py  |  0
 graph/planner/requirements.txt |  0
 3 files changed, 92 insertions(+)
 create mode 100644 graph/planner/planner.py
 create mode 100644 graph/planner/planner_test.py
 create mode 100644 graph/planner/requirements.txt

diff --git a/graph/planner/planner.py b/graph/planner/planner.py
new file mode 100644
index 0000000..8643db8
--- /dev/null
+++ b/graph/planner/planner.py
@@ -0,0 +1,92 @@
+from dataclasses import dataclass, field
+from enum import Enum
+
+
+class EdgeType(Enum):
+    DEPENDENCY = 0
+    TOOL = 1
+
+
+@dataclass
+class Edge:
+    u: str
+    v: str
+    type: EdgeType = field(default=EdgeType.DEPENDENCY)
+
+
+class CycleException(Exception):
+    pass
+
+
+class DirectAcyclicGraph:
+    _g: dict[str, list[(str, EdgeType)]]
+    _topological_order: list[str]
+
+    def __init__(self, edges: list[Edge]):
+        self._g = {}
+        for e in edges:  # e = (u, v)
+            if self._g.get(e.u) is None:
+                self._g[e.u] = [(e.v, e.type)]
+            else:
+                if (e.v, e.type) not in self._g[e.u]:
+                    self._g[e.u].append((e.v, e.type))
+            if self._g.get(e.v) is None:
+                self._g[e.v] = []
+
+        self._topsort()
+
+    def _topsort(self):
+        edges = {u: iter([v for (v, _) in value]) for (u, value) in self._g.items()}
+        result = []
+
+        while len(edges):
+            # print(f"edges: {edges}")
+            dfs_stack = [list(edges.keys())[0]]
+            while dfs_stack:
+                # print("-" * 25)
+                # print(f"stack: {stack}")
+                # print(f"edges: {edges}")
+                u = dfs_stack.pop()
+                # print(f"node: {u}")
+                if u not in result:
+                    # print(f"node: {u} not visited")
+                    adjacent = edges[u]
+                    try:
+                        v = next(adjacent)
+                        if v in dfs_stack:  # cycle
+                            raise CycleException(f"{dfs_stack} + {u} -> {v}")
+                        dfs_stack.append(u)  # recursive return
+                        if v not in result:
+                            dfs_stack.append(v)  # recursive call
+                    except StopIteration:
+                        # print(f"finished {u}")
+                        del edges[u]
+                        result.append(u)
+
+        result.reverse()
+        self._topological_order = result
+
+    def print(self):
+        print(self._g)
+        print(f"topological order => {self._topological_order}")
+
+
+g = DirectAcyclicGraph(
+    # [Edge("a", "b"), Edge("b", "c"), Edge("c", "d"), Edge("d", "e"), Edge("d", "e")]
+    # [Edge("a", "b"), Edge("b", "c"), Edge("c", "d"), Edge("d", "a")]
+    [
+        Edge("a", "b"),
+        Edge("b", "c"),
+        Edge("b", "d"),
+        Edge("b", "e"),
+        Edge("c", "c1"),
+        Edge("c", "c2"),
+        Edge("d", "d1"),
+        Edge("d", "d2"),
+        Edge("c1", "c1d1"),
+        Edge("d1", "c1d1"),
+        Edge("c2", "c2d2"),
+        Edge("d2", "c2d2"),
+    ]
+)
+g.print()
diff --git a/graph/planner/planner_test.py b/graph/planner/planner_test.py
new file mode 100644
index 0000000..e69de29
diff --git a/graph/planner/requirements.txt b/graph/planner/requirements.txt
new file mode 100644
index 0000000..e69de29