import os
import uuid

HEADER = """
graph {
graph [splines=ortho, nodesep=1]
node [color=white]
edge [headport=n, tailport=s]
compound=true

"""

FOOTER = """
}
"""

# TODO:
# Add hidden nodes in each cluster above visible nodes connected by hidden edges and attach visible edges to them
# - also see: https://stackoverflow.com/questions/53862417/how-to-set-head-and-tail-position-in-nodes-graphviz
# Solve layering of clusters
# - https://observablehq.com/@gordonsmith/church

class Graph:
    def __init__(self):
        self.layers = {}
        self.blocks = {}
        self.nodes = []
        self.links = {}
        self.dot_file = ""
    
    def __str__(self):
        return self.dot_file
    
    def get_id(self):
        return "id" + str(uuid.uuid4().hex)
    
    def process_blocks(self, data):
        blocks = data.get('blocks', [])
        
        for block in blocks:
            block_id = self.get_id()
            
            new_block = {
                "label": block.get("label", ""),
                #"layer": block.get("layer", 0),
                "texts": []
            }

            #layer = block.get("layer", 0)
            #if layer not in self.layers:
            #    self.layers[layer] = []

            for text in block.get("texts", []):
                node_id = self.get_id()
                self.nodes.append({"id": node_id, "text": text.get("text", "")})
                new_block["texts"].append(node_id)
                #self.layers[layer].append(node_id)

                links = text.get("links", {})
                if links != {}:
                    from_links = links.get("from", [])
                    to_links = links.get("to", [])
                    for from_link in from_links:
                        self.links[from_link] = {"from": node_id, "to": "", "head": ""}
                    for to_link in to_links:
                        if to_link in self.links:
                            self.links[to_link]["to"] = node_id
                            self.links[to_link]["head"] = block_id
            
            self.blocks[block_id] = new_block

    def build_dot(self):
        self.dot_file = HEADER

        for node in self.nodes:
            self.dot_file += f"{node['id']} [label=\"{node['text']}\"]\n"
        self.dot_file += "\n"
        
        for block_id, block in self.blocks.items():
            self.dot_file += f"subgraph cluster_{block_id} {{\n"
            self.dot_file += f"label=\"{block['label']}\"\n"
            self.dot_file += f"labeljust=l\n"
            for node in block["texts"]:
                self.dot_file += f"{node}\n"
            self.dot_file += "}\n\n"
        
        #for layer in self.layers.keys():
        #    self.dot_file += f"layer{layer} [style=invis]\n"

        #ranking = " -- ".join([f"layer{layer}" for layer in self.layers.keys()])
        #self.dot_file += f"{ranking} [style=invis]\n"

        for link in self.links:
            if self.links[link]["to"] != "":
                self.dot_file += f"{self.links[link]['from']} -- {self.links[link]['to']}"
                if self.links[link]["head"] != "":
                    self.dot_file += f" [lhead=cluster_{self.links[link]['head']}]"
                self.dot_file += "\n"
        
        #for layer, nodes in self.layers.items():
        #    self.dot_file += "{rank=same; "
        #    self.dot_file += "layer{layer}; "
        #    for node in nodes:
        #        self.dot_file += f"{node}; "
        #    self.dot_file += "}\n"

        self.dot_file += FOOTER
    
    def make_dot(self, format="svg", dot_file="dot.gv", svg_file="graph.svg"):
        if self.dot_file != "":
            with open(dot_file, "w") as f:
                f.write(self.dot_file)
            if format == "svg":
                os.system(f"dot -T{format} {dot_file} -o {svg_file}")