from dataclasses import dataclass, field
from typing import List, Dict, Any, Optional


@dataclass
class Node:
    id: str
    label: str = ""
    type: str = ""
    metadata: Dict[str, Any] = field(default_factory=dict)


@dataclass
class Edge:
    source: str
    target: str
    label: str = ""
    metadata: Dict[str, Any] = field(default_factory=dict)


@dataclass
class FlowGraph:
    nodes: List[Node] = field(default_factory=list)
    edges: List[Edge] = field(default_factory=list)

    def find_node(self, node_id: str) -> Optional[Node]:
        for n in self.nodes:
            if n.id == node_id:
                return n
        return None


def table_to_flowgraph(nodes_table, edges_table) -> FlowGraph:
    """
    Convert Gradio Dataframe tables into a FlowGraph instance.
    nodes_table: list of [id, label, type]
    edges_table: list of [source, target, label]
    """
    graph = FlowGraph()

    if nodes_table is None:
        nodes_table = []
    if edges_table is None:
        edges_table = []

    for row in nodes_table:
        if not row:
            continue
        row = list(row) + ["", "", ""]
        nid, label, ntype = row[0], row[1], row[2]
        if not nid:
            continue
        graph.nodes.append(Node(id=str(nid), label=str(label or nid), type=str(ntype or "")))

    for row in edges_table:
        if not row:
            continue
        row = list(row) + ["", "", ""]
        src, dst, elabel = row[0], row[1], row[2]
        if not src or not dst:
            continue
        graph.edges.append(Edge(source=str(src), target=str(dst), label=str(elabel or "")))

    return graph