import graphviz
import json
from tempfile import NamedTemporaryFile
import os

def generate_class_diagram(json_input: str, output_format: str) -> str:
    """
    Generates a class diagram from JSON input.

    Args:
        json_input (str): A JSON string describing the class diagram structure.
                          It must follow the Expected JSON Format Example below.
                          
        output_format (str): The output format for the generated diagram.
                            Supported formats: "png" or "svg"

    Expected JSON Format Example:
    {
      "classes": [
        {
          "name": "Student",
          "type": "class",
          "attributes": [
            {"name": "studentId", "type": "String", "visibility": "-"},
            {"name": "username", "type": "String", "visibility": "+"},
            {"name": "email", "type": "String", "visibility": "+"},
            {"name": "enrollmentDate", "type": "Date", "visibility": "+"},
            {"name": "currentLevel", "type": "String", "visibility": "+"}
          ],
          "methods": [
            {"name": "Student", "parameters": [{"name": "username", "type": "String"}, {"name": "email", "type": "String"}], "return_type": "Student", "visibility": "+"},
            {"name": "enrollCourse", "parameters": [{"name": "courseId", "type": "String"}], "return_type": "boolean", "visibility": "+"},
            {"name": "updateProgress", "parameters": [{"name": "lessonId", "type": "String"}], "return_type": "void", "visibility": "+"}
          ]
        },
        {
          "name": "CourseEnrollment",
          "type": "class",
          "attributes": [
            {"name": "enrollmentId", "type": "String", "visibility": "-"},
            {"name": "studentId", "type": "String", "visibility": "+"},
            {"name": "courseId", "type": "String", "visibility": "+"},
            {"name": "enrollmentDate", "type": "Date", "visibility": "+"},
            {"name": "progress", "type": "double", "visibility": "+"}
          ],
          "methods": [
            {"name": "CourseEnrollment", "parameters": [{"name": "studentId", "type": "String"}, {"name": "courseId", "type": "String"}], "return_type": "CourseEnrollment", "visibility": "+"},
            {"name": "calculateProgress", "return_type": "double", "visibility": "+"}
          ]
        },
        {
          "name": "Course",
          "type": "class",
          "attributes": [
            {"name": "courseId", "type": "String", "visibility": "-"},
            {"name": "title", "type": "String", "visibility": "+"},
            {"name": "description", "type": "String", "visibility": "+"},
            {"name": "difficulty", "type": "String", "visibility": "+"},
            {"name": "duration", "type": "int", "visibility": "+"}
          ],
          "methods": [
            {"name": "Course", "parameters": [{"name": "title", "type": "String"}], "return_type": "Course", "visibility": "+"},
            {"name": "addLesson", "parameters": [{"name": "lesson", "type": "Lesson"}], "return_type": "void", "visibility": "+"}
          ]
        },
        {
          "name": "Instructor",
          "type": "class",
          "attributes": [
            {"name": "instructorId", "type": "String", "visibility": "-"},
            {"name": "name", "type": "String", "visibility": "+"},
            {"name": "expertise", "type": "String", "visibility": "+"},
            {"name": "rating", "type": "double", "visibility": "+"}
          ],
          "methods": [
            {"name": "Instructor", "parameters": [{"name": "name", "type": "String"}, {"name": "expertise", "type": "String"}], "return_type": "Instructor", "visibility": "+"},
            {"name": "createCourse", "parameters": [{"name": "title", "type": "String"}], "return_type": "Course", "visibility": "+"}
          ]
        },
        {
          "name": "Lesson",
          "type": "class",
          "attributes": [
            {"name": "lessonId", "type": "String", "visibility": "-"},
            {"name": "title", "type": "String", "visibility": "+"},
            {"name": "courseId", "type": "String", "visibility": "+"},
            {"name": "duration", "type": "int", "visibility": "+"},
            {"name": "order", "type": "int", "visibility": "+"}
          ],
          "methods": [
            {"name": "Lesson", "parameters": [{"name": "title", "type": "String"}], "return_type": "Lesson", "visibility": "+"},
            {"name": "markCompleted", "parameters": [{"name": "studentId", "type": "String"}], "return_type": "void", "visibility": "+"}
          ]
        },
        {
          "name": "VideoContent",
          "type": "class",
          "attributes": [
            {"name": "videoId", "type": "String", "visibility": "-"},
            {"name": "lessonId", "type": "String", "visibility": "+"},
            {"name": "videoUrl", "type": "String", "visibility": "+"},
            {"name": "duration", "type": "int", "visibility": "+"}
          ],
          "methods": [
            {"name": "VideoContent", "parameters": [{"name": "lessonId", "type": "String"}, {"name": "videoUrl", "type": "String"}], "return_type": "VideoContent", "visibility": "+"},
            {"name": "play", "return_type": "void", "visibility": "+"}
          ]
        },
        {
          "name": "WatchProgress",
          "type": "class",
          "attributes": [
            {"name": "progressId", "type": "String", "visibility": "-"},
            {"name": "studentId", "type": "String", "visibility": "+"},
            {"name": "videoId", "type": "String", "visibility": "+"},
            {"name": "watchedMinutes", "type": "int", "visibility": "+"}
          ],
          "methods": [
            {"name": "WatchProgress", "parameters": [{"name": "studentId", "type": "String"}, {"name": "videoId", "type": "String"}], "return_type": "WatchProgress", "visibility": "+"},
            {"name": "updateProgress", "parameters": [{"name": "minutes", "type": "int"}], "return_type": "void", "visibility": "+"}
          ]
        },
        {
          "name": "Quiz",
          "type": "class",
          "attributes": [
            {"name": "quizId", "type": "String", "visibility": "-"},
            {"name": "lessonId", "type": "String", "visibility": "+"},
            {"name": "title", "type": "String", "visibility": "+"},
            {"name": "passingScore", "type": "int", "visibility": "+"}
          ],
          "methods": [
            {"name": "Quiz", "parameters": [{"name": "title", "type": "String"}], "return_type": "Quiz", "visibility": "+"},
            {"name": "addQuestion", "parameters": [{"name": "question", "type": "Question"}], "return_type": "void", "visibility": "+"}
          ]
        },
        {
          "name": "Question",
          "type": "class",
          "attributes": [
            {"name": "questionId", "type": "String", "visibility": "-"},
            {"name": "quizId", "type": "String", "visibility": "+"},
            {"name": "questionText", "type": "String", "visibility": "+"},
            {"name": "questionType", "type": "String", "visibility": "+"}
          ],
          "methods": [
            {"name": "Question", "parameters": [{"name": "questionText", "type": "String"}], "return_type": "Question", "visibility": "+"},
            {"name": "addOption", "parameters": [{"name": "option", "type": "String"}], "return_type": "void", "visibility": "+"}
          ]
        },
        {
          "name": "QuizAttempt",
          "type": "class",
          "attributes": [
            {"name": "attemptId", "type": "String", "visibility": "-"},
            {"name": "studentId", "type": "String", "visibility": "+"},
            {"name": "quizId", "type": "String", "visibility": "+"},
            {"name": "score", "type": "int", "visibility": "+"},
            {"name": "attemptDate", "type": "Date", "visibility": "+"}
          ],
          "methods": [
            {"name": "QuizAttempt", "parameters": [{"name": "studentId", "type": "String"}, {"name": "quizId", "type": "String"}], "return_type": "QuizAttempt", "visibility": "+"},
            {"name": "submitAnswer", "parameters": [{"name": "questionId", "type": "String"}, {"name": "answer", "type": "String"}], "return_type": "void", "visibility": "+"}
          ]
        },
        {
          "name": "Discussion",
          "type": "class",
          "attributes": [
            {"name": "discussionId", "type": "String", "visibility": "-"},
            {"name": "courseId", "type": "String", "visibility": "+"},
            {"name": "title", "type": "String", "visibility": "+"},
            {"name": "createdDate", "type": "Date", "visibility": "+"}
          ],
          "methods": [
            {"name": "Discussion", "parameters": [{"name": "title", "type": "String"}], "return_type": "Discussion", "visibility": "+"},
            {"name": "addPost", "parameters": [{"name": "studentId", "type": "String"}, {"name": "message", "type": "String"}], "return_type": "void", "visibility": "+"}
          ]
        },
        {
          "name": "Post",
          "type": "class",
          "attributes": [
            {"name": "postId", "type": "String", "visibility": "-"},
            {"name": "discussionId", "type": "String", "visibility": "+"},
            {"name": "authorId", "type": "String", "visibility": "+"},
            {"name": "content", "type": "String", "visibility": "+"},
            {"name": "postDate", "type": "Date", "visibility": "+"}
          ],
          "methods": [
            {"name": "Post", "parameters": [{"name": "authorId", "type": "String"}, {"name": "content", "type": "String"}], "return_type": "Post", "visibility": "+"},
            {"name": "reply", "parameters": [{"name": "replyContent", "type": "String"}], "return_type": "void", "visibility": "+"}
          ]
        },
        {
          "name": "Certificate",
          "type": "class",
          "attributes": [
            {"name": "certificateId", "type": "String", "visibility": "-"},
            {"name": "studentId", "type": "String", "visibility": "+"},
            {"name": "courseId", "type": "String", "visibility": "+"},
            {"name": "issueDate", "type": "Date", "visibility": "+"},
            {"name": "grade", "type": "String", "visibility": "+"}
          ],
          "methods": [
            {"name": "Certificate", "parameters": [{"name": "studentId", "type": "String"}, {"name": "courseId", "type": "String"}], "return_type": "Certificate", "visibility": "+"},
            {"name": "generatePDF", "return_type": "String", "visibility": "+"}
          ]
        },
        {
          "name": "Payment",
          "type": "class",
          "attributes": [
            {"name": "paymentId", "type": "String", "visibility": "-"},
            {"name": "studentId", "type": "String", "visibility": "+"},
            {"name": "courseId", "type": "String", "visibility": "+"},
            {"name": "amount", "type": "double", "visibility": "+"},
            {"name": "paymentDate", "type": "Date", "visibility": "+"}
          ],
          "methods": [
            {"name": "Payment", "parameters": [{"name": "studentId", "type": "String"}, {"name": "amount", "type": "double"}], "return_type": "Payment", "visibility": "+"},
            {"name": "processPayment", "return_type": "boolean", "visibility": "+"}
          ]
        }
      ],
      "relationships": [
        {
          "from": "Student",
          "to": "CourseEnrollment",
          "type": "association",
          "multiplicity_from": "1",
          "multiplicity_to": "*"
        },
        {
          "from": "CourseEnrollment",
          "to": "Course",
          "type": "association",
          "multiplicity_from": "*",
          "multiplicity_to": "1"
        },
        {
          "from": "Instructor",
          "to": "Course",
          "type": "association",
          "multiplicity_from": "1",
          "multiplicity_to": "*"
        },
        {
          "from": "Course",
          "to": "Lesson",
          "type": "composition",
          "multiplicity_from": "1",
          "multiplicity_to": "*"
        },
        {
          "from": "Lesson",
          "to": "VideoContent",
          "type": "association",
          "multiplicity_from": "1",
          "multiplicity_to": "*"
        },
        {
          "from": "Student",
          "to": "WatchProgress",
          "type": "association",
          "multiplicity_from": "1",
          "multiplicity_to": "*"
        },
        {
          "from": "VideoContent",
          "to": "WatchProgress",
          "type": "association",
          "multiplicity_from": "1",
          "multiplicity_to": "*"
        },
        {
          "from": "Lesson",
          "to": "Quiz",
          "type": "association",
          "multiplicity_from": "1",
          "multiplicity_to": "*"
        },
        {
          "from": "Quiz",
          "to": "Question",
          "type": "composition",
          "multiplicity_from": "1",
          "multiplicity_to": "*"
        },
        {
          "from": "Student",
          "to": "QuizAttempt",
          "type": "association",
          "multiplicity_from": "1",
          "multiplicity_to": "*"
        },
        {
          "from": "Quiz",
          "to": "QuizAttempt",
          "type": "association",
          "multiplicity_from": "1",
          "multiplicity_to": "*"
        },
        {
          "from": "Course",
          "to": "Discussion",
          "type": "aggregation",
          "multiplicity_from": "1",
          "multiplicity_to": "*"
        },
        {
          "from": "Discussion",
          "to": "Post",
          "type": "composition",
          "multiplicity_from": "1",
          "multiplicity_to": "*"
        },
        {
          "from": "Student",
          "to": "Certificate",
          "type": "association",
          "multiplicity_from": "1",
          "multiplicity_to": "*"
        },
        {
          "from": "Student",
          "to": "Payment",
          "type": "association",
          "multiplicity_from": "1",
          "multiplicity_to": "*"
        }
      ]
    }

    Returns:
        str: The filepath to the generated image file.
    """
    try:
        if not json_input.strip():
            return "Error: Empty input"
            
        data = json.loads(json_input)
        
        if 'classes' not in data:
            raise ValueError("Missing required field: classes")

        dot = graphviz.Digraph(comment='Class Diagram')
        dot.attr(rankdir='TB', bgcolor='white', pad='0.5', nodesep='0.8', ranksep='1.2', splines='ortho')
        dot.attr('node', shape='plaintext', fontname='Arial', fontsize='11')
        dot.attr('edge', color='#4a4a4a', fontname='Arial', fontsize='9', minlen='1')
        
        header_color = '#BEBEBE'
        body_color = '#E8E8E8'
        
        classes = data.get('classes', [])
        relationships = data.get('relationships', [])
        
        for cls in classes:
            class_name = cls.get('name')
            class_type = cls.get('type', 'class')
            attributes = cls.get('attributes', [])
            methods = cls.get('methods', [])
            
            if not class_name:
                continue
            
            html_label = f'<TABLE BORDER="1" CELLBORDER="0" CELLSPACING="0" CELLPADDING="5" STYLE="rounded" BGCOLOR="{body_color}">'
            
            if class_type == 'abstract':
                html_label += f'<TR><TD ALIGN="CENTER" BGCOLOR="{header_color}"><B>&lt;&lt;abstract&gt;&gt;<BR/>{class_name}</B></TD></TR>'
            elif class_type == 'interface':
                html_label += f'<TR><TD ALIGN="CENTER" BGCOLOR="{header_color}"><B>&lt;&lt;interface&gt;&gt;<BR/>{class_name}</B></TD></TR>'
            elif class_type == 'enum':
                html_label += f'<TR><TD ALIGN="CENTER" BGCOLOR="{header_color}"><B>&lt;&lt;enumeration&gt;&gt;<BR/>{class_name}</B></TD></TR>'
            else:
                html_label += f'<TR><TD ALIGN="CENTER" BGCOLOR="{header_color}"><B>{class_name}</B></TD></TR>'
            
            html_label += f'<HR/><TR><TD BGCOLOR="{body_color}" HEIGHT="5"></TD></TR>'
            
            if attributes:
                for attr in attributes:
                    visibility = attr.get('visibility', '+')
                    name = attr.get('name', '')
                    attr_type = attr.get('type', '')
                    is_static = attr.get('static', False)
                    
                    line = f"{visibility} {name}"
                    if attr_type:
                        line += f" : {attr_type}"
                    if is_static:
                        line = f"<U>{line}</U>"
                    
                    html_label += f'<TR><TD ALIGN="LEFT" BGCOLOR="{body_color}">{line}</TD></TR>'
            else:
                html_label += f'<TR><TD ALIGN="LEFT" BGCOLOR="{body_color}"> </TD></TR>'
            
            html_label += f'<TR><TD BGCOLOR="{body_color}" HEIGHT="5"></TD></TR><HR/><TR><TD BGCOLOR="{body_color}" HEIGHT="5"></TD></TR>'
            
            if methods:
                for method in methods:
                    visibility = method.get('visibility', '+')
                    name = method.get('name', '')
                    parameters = method.get('parameters', [])
                    return_type = method.get('return_type', 'void')
                    is_static = method.get('static', False)
                    is_abstract = method.get('abstract', False)
                    
                    line = f"{visibility} {name}("
                    if parameters:
                        params = []
                        for param in parameters:
                            param_name = param.get('name', '')
                            param_type = param.get('type', '')
                            params.append(f"{param_name}: {param_type}")
                        line += ", ".join(params)
                    line += f") : {return_type}"
                    
                    if is_static:
                        line = f"<U>{line}</U>"
                    if is_abstract:
                        line = f"<I>{line}</I>"
                    
                    html_label += f'<TR><TD ALIGN="LEFT" BGCOLOR="{body_color}">{line}</TD></TR>'
            else:
                html_label += f'<TR><TD ALIGN="LEFT" BGCOLOR="{body_color}"> </TD></TR>'
            
            html_label += '</TABLE>'
            
            dot.node(class_name, f'<{html_label}>', style='rounded')
        
        for relationship in relationships:
            from_class = relationship.get('from')
            to_class = relationship.get('to')
            rel_type = relationship.get('type', 'association')
            label = relationship.get('label', '')
            multiplicity_from = relationship.get('multiplicity_from', '')
            multiplicity_to = relationship.get('multiplicity_to', '')
            
            if not from_class or not to_class:
                continue
            
            edge_attrs = {
                'color': '#4a4a4a'
            }
            
            if multiplicity_from:
                edge_attrs['taillabel'] = multiplicity_from
            
            if multiplicity_to:
                edge_attrs['headlabel'] = multiplicity_to
            
            if rel_type == 'inheritance':
                edge_attrs['arrowhead'] = 'empty'
                edge_attrs['color'] = '#4a4a4a'
            elif rel_type == 'composition':
                edge_attrs['arrowhead'] = 'normal'
                edge_attrs['arrowtail'] = 'diamond'
                edge_attrs['dir'] = 'both'
                edge_attrs['color'] = '#4a4a4a'
            elif rel_type == 'aggregation':
                edge_attrs['arrowhead'] = 'normal'
                edge_attrs['arrowtail'] = 'odiamond'
                edge_attrs['dir'] = 'both'
                edge_attrs['color'] = '#4a4a4a'
            elif rel_type == 'realization':
                edge_attrs['arrowhead'] = 'empty'
                edge_attrs['style'] = 'dashed'
                edge_attrs['color'] = '#4a4a4a'
            elif rel_type == 'dependency':
                edge_attrs['arrowhead'] = 'normal'
                edge_attrs['style'] = 'dashed'
                edge_attrs['color'] = '#4a4a4a'
            else:
                edge_attrs['arrowhead'] = 'normal'
                edge_attrs['color'] = '#4a4a4a'
            
            dot.edge(from_class, to_class, **edge_attrs)

        with NamedTemporaryFile(delete=False, suffix=f'.{output_format}') as tmp:
            dot.render(tmp.name, format=output_format, cleanup=True)
            return f"{tmp.name}.{output_format}"

    except json.JSONDecodeError:
        return "Error: Invalid JSON format"
    except Exception as e:
        return f"Error: {str(e)}"