import os
import sys
import shutil
import json
import datetime

# Configuration
HMCMKIT_ROOT = ".hmcmkit"
CONFIG_PATH = os.path.join(HMCMKIT_ROOT, "config.json")
TEMPLATE_DIR = os.path.join(HMCMKIT_ROOT, "knowledge", "templates")

def load_config():
    with open(CONFIG_PATH, 'r', encoding='utf-8') as f:
        return json.load(f)

def get_target_path(config, phase, feature_name):
    """
    Resolves the target path based on config.json 'pdca' section.
    """
    pdca_config = config.get('pdca', {})
    path_key = f"{phase.lower()}DocPaths" # e.g. planDocPaths
    
    paths = pdca_config.get(path_key, [])
    if not paths:
        # Fallback defaults
        defaults = {
            "plan": f"docs/01-plan/{feature_name}.plan.md",
            "design": f"docs/02-design/{feature_name}.design.md",
            "gap-analysis": f"docs/03-check/{feature_name}.gap.md",
            "report": f"docs/04-act/{feature_name}.report.md"
        }
        return defaults.get(phase.lower(), f"docs/{phase}/{feature_name}.md")
        
    # Use the first configured path
    first_path = paths[0]
    return first_path.replace("{feature}", feature_name).replace("{type}", phase)

def scaffold(phase, feature_name):
    config = load_config()
    
    # 1. Identify Template
    template_types = config.get('templates', {}).get('types', {})
    template_file = template_types.get(phase.lower())
    
    if not template_file:
        print(f"❌ Error: No template defined for phase '{phase}'")
        return False
        
    template_path = os.path.join(TEMPLATE_DIR, template_file)
    if not os.path.exists(template_path):
         # Try looking for Level Variants (e.g. plan-starter.template.md)
         # For now, just error
         print(f"❌ Error: Template file not found at {template_path}")
         return False
         
    # 2. Identify Target Path
    target_path = get_target_path(config, phase, feature_name)
    
    # 3. Create Directory
    os.makedirs(os.path.dirname(target_path), exist_ok=True)
    
    if os.path.exists(target_path):
        print(f"⚠️  Target file already exists: {target_path}")
        # v1.0.1: Auto Snapshot
        try:
            from snapshot import create_snapshot
            create_snapshot(target_path)
            print(f"   (Backup created before potential overwrite)")
        except ImportError:
            pass
        return False
        
    # 4. Read & process Template
    with open(template_path, 'r', encoding='utf-8') as f:
        content = f.read()
    
    # Simple Variable Replacement
    content = content.replace("{{feature}}", feature_name)
    content = content.replace("{{date}}", datetime.datetime.now().strftime("%Y-%m-%d"))
    
    # 5. Write File
    with open(target_path, 'w', encoding='utf-8') as f:
        f.write(content)
        
    print(f"✅ Created {phase.upper()} document: {target_path}")
    return True

if __name__ == "__main__":
    if len(sys.argv) < 3:
        print("Usage: python scaffold.py <phase> <feature_name>")
        print("Phases: plan, design, gap-analysis, report")
        sys.exit(1)
        
    phase = sys.argv[1]
    feature = sys.argv[2]
    scaffold(phase, feature)