wbs_diagram_generator.py

import graphviz
import json
from tempfile import NamedTemporaryFile
import os
from graph_generator_utils import add_nodes_and_edges 

def generate_wbs_diagram(json_input: str, output_format: str) -> str:
    """
    Generates a Work Breakdown Structure (WBS) Diagram from JSON input.

    Args:
        json_input (str): A JSON string describing the WBS structure.
                          It must follow the Expected JSON Format Example below.

    Expected JSON Format Example:
    {
      "project_title": "AI Model Development Project",
      "phases": [
        {
          "id": "phase_prep",
          "label": "Preparation",
          "tasks": [
            {
              "id": "task_1_1_vision",
              "label": "Identify Vision",
              "subtasks": [
                {
                  "id": "subtask_1_1_1_design_staff",
                  "label": "Design & Staffing",
                  "sub_subtasks": [
                    {
                      "id": "ss_task_1_1_1_1_env_setup",
                      "label": "Environment Setup",
                      "sub_sub_subtasks": [
                        {
                          "id": "sss_task_1_1_1_1_1_lib_install",
                          "label": "Install Libraries",
                          "final_level_tasks": [
                            {"id": "ft_1_1_1_1_1_1_data_access", "label": "Grant Data Access"}
                          ]
                        }
                      ]
                    }
                  ]
                }
              ]
            }
          ]
        },
        {
          "id": "phase_plan",
          "label": "Planning",
          "tasks": [
            {
              "id": "task_2_1_cost_analysis",
              "label": "Cost Analysis",
              "subtasks": [
                {
                  "id": "subtask_2_1_1_benefit_analysis",
                  "label": "Benefit Analysis",
                  "sub_subtasks": [
                    {
                      "id": "ss_task_2_1_1_1_risk_assess",
                      "label": "AI Risk Assessment",
                      "sub_sub_subtasks": [
                        {
                          "id": "sss_task_2_1_1_1_1_model_selection",
                          "label": "Model Selection",
                          "final_level_tasks": [
                            {"id": "ft_2_1_1_1_1_1_data_strategy", "label": "Data Strategy"}
                          ]
                        }
                      ]
                    }
                  ]
                }
              ]
            }
          ]
        },
        {
          "id": "phase_dev",
          "label": "Development",
          "tasks": [
            {
              "id": "task_3_1_change_mgmt",
              "label": "Data Preprocessing",
              "subtasks": [
                {
                  "id": "subtask_3_1_1_implementation",
                  "label": "Feature Engineering",
                  "sub_subtasks": [
                    {
                      "id": "ss_task_3_1_1_1_beta_testing",
                      "label": "Model Training",
                      "sub_sub_subtasks": [
                        {
                          "id": "sss_task_3_1_1_1_1_other_task",
                          "label": "Model Evaluation",
                          "final_level_tasks": [
                            {"id": "ft_3_1_1_1_1_1_hyperparam_tune", "label": "Hyperparameter Tuning"}
                          ]
                        }
                      ]
                    }
                  ]
                }
              ]
            }
          ]
        }
      ]
    }

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

        dot = graphviz.Digraph(
            name='WBSDiagram',
            format='png',
            graph_attr={
                'rankdir': 'TB',        # Top-to-Bottom hierarchy
                'splines': 'ortho',     # Straight lines
                'bgcolor': 'white',     # White background
                'pad': '0.5',           # Padding
                'ranksep': '0.6',       # Adjust vertical separation between ranks
                'nodesep': '0.5'        # Adjust horizontal separation between nodes
            }
        )
        
        base_color = '#19191a' # Hardcoded base color

        # Project Title node (main node)
        dot.node(
            'project_root',
            data['project_title'],
            shape='box',
            style='filled,rounded',
            fillcolor=base_color,
            fontcolor='white',
            fontsize='18'
        )

        # Helper for color and font based on depth for WBS
        def get_gradient_color(depth, base_hex_color, lightening_factor=0.12):
            base_r = int(base_hex_color[1:3], 16)
            base_g = int(base_hex_color[3:5], 16)
            base_b = int(base_hex_color[5:7], 16)

            current_r = base_r + int((255 - base_r) * depth * lightening_factor)
            current_g = base_g + int((255 - base_g) * depth * lightening_factor)
            current_b = base_b + int((255 - base_b) * depth * lightening_factor)
            
            return f'#{min(255, current_r):02x}{min(255, current_g):02x}{min(255, current_b):02x}'

        def get_font_color_for_background(depth, base_hex_color, lightening_factor=0.12):
            base_r = int(base_hex_color[1:3], 16)
            base_g = int(base_hex_color[3:5], 16)
            base_b = int(base_hex_color[5:7], 16)
            current_r = base_r + (255 - base_r) * depth * lightening_factor
            current_g = base_g + (255 - base_g) * depth * lightening_factor
            current_b = base_b + (255 - base_b) * depth * lightening_factor
            
            luminance = (0.2126 * current_r + 0.7152 * current_g + 0.0722 * current_b) / 255
            return 'white' if luminance < 0.5 else 'black'

        def _add_wbs_nodes_recursive(parent_id, current_level_tasks, current_depth):
            for task_data in current_level_tasks:
                task_id = task_data.get('id')
                task_label = task_data.get('label')
                
                if not all([task_id, task_label]):
                    raise ValueError(f"Invalid task data at depth {current_depth}: {task_data}")

                node_fill_color = get_gradient_color(current_depth, base_color)
                node_font_color = get_font_color_for_background(current_depth, base_color)
                font_size = max(9, 14 - (current_depth * 2))

                dot.node(
                    task_id,
                    task_label,
                    shape='box',
                    style='filled,rounded',
                    fillcolor=node_fill_color,
                    fontcolor=node_font_color,
                    fontsize=str(font_size)
                )
                dot.edge(parent_id, task_id, color='#4a4a4a', arrowhead='none')

                # Recursively call for next level of tasks (subtasks, sub_subtasks, etc.)
                # This handles arbitrary nested keys like 'subtasks', 'sub_subtasks', 'final_level_tasks'
                next_level_keys = ['tasks', 'subtasks', 'sub_subtasks', 'sub_sub_subtasks', 'final_level_tasks']
                for key_idx, key in enumerate(next_level_keys):
                    if key in task_data and isinstance(task_data[key], list):
                        _add_wbs_nodes_recursive(task_id, task_data[key], current_depth + 1)
                        break # Only process the first found sub-level key

        # Process phases (level 1 from project_root)
        phase_depth = 1
        for phase in data['phases']:
            phase_id = phase.get('id')
            phase_label = phase.get('label')
            
            if not all([phase_id, phase_label]):
                raise ValueError(f"Invalid phase data: {phase}")

            phase_fill_color = get_gradient_color(phase_depth, base_color)
            phase_font_color = get_font_color_for_background(phase_depth, base_color)
            font_size_phase = max(9, 14 - (phase_depth * 2))

            dot.node(
                phase_id,
                phase_label,
                shape='box',
                style='filled,rounded',
                fillcolor=phase_fill_color,
                fontcolor=phase_font_color,
                fontsize=str(font_size_phase)
            )
            dot.edge('project_root', phase_id, color='#4a4a4a', arrowhead='none')

            # Start recursion for tasks under this phase
            if 'tasks' in phase and isinstance(phase['tasks'], list):
                _add_wbs_nodes_recursive(phase_id, phase['tasks'], phase_depth + 1)

        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)}"