import csv
import config
from utils import normalize, find_csv_path

def read_manifest(project_name):
    """Reads the manifest CSV for a specific project into a list of dictionaries."""
    csv_filepath = find_csv_path(project_name)
    if not csv_filepath:
        return None

    print(f"[{project_name}] Reading manifest: {csv_filepath}")
    manifest_items = []
    # Only require Alias and Panel now for basic grouping
    required_cols = {config.CSV_ALIAS_COL, config.CSV_PANEL_COL}
    optional_cols = {config.CSV_EQ_TYPE_COL, config.CSV_CONV_TYPE_COL}
    try:
        # Revert back to 'utf-8-sig' to handle potential BOM from Excel
        with open(csv_filepath, mode='r', newline='', encoding='utf-8-sig') as infile:
            reader = csv.DictReader(infile)
            # Strip whitespace from headers for reliable matching
            headers = set(h.strip() for h in reader.fieldnames if h) # Added 'if h' to handle potential empty headers

            # Check for required columns
            missing_required = required_cols - headers
            if missing_required:
                 print(f"Error: Missing required columns in CSV '{csv_filepath}': {', '.join(missing_required)}")
                 print(f"Available columns: {', '.join(headers)}")
                 return None

            for row in reader:
                # Strip whitespace from values as well
                alias = row.get(config.CSV_ALIAS_COL, "").strip()
                panel = row.get(config.CSV_PANEL_COL, "").strip()

                # Add if Alias and Control Panel are present (Panel needed for grouping results later)
                if alias and panel:
                    item = {
                        "alias": alias,
                        "normalized_alias": normalize(alias),
                        "control_panel": panel,
                        # Add optional data if columns exist and have values
                        "equipment_type": row.get(config.CSV_EQ_TYPE_COL, "").strip() if config.CSV_EQ_TYPE_COL in headers else "N/A",
                        "conveyor_type": row.get(config.CSV_CONV_TYPE_COL, "").strip() if config.CSV_CONV_TYPE_COL in headers else "N/A",
                        # Status fields to be filled later
                        "found_scada": False,
                        "found_drawing": False
                    }
                    manifest_items.append(item)
                elif alias and not panel:
                    print(f"Warning: Alias '{alias}' found in CSV but is missing its '{config.CSV_PANEL_COL}'. Skipping.")
                # Add other specific warnings if needed

    except FileNotFoundError:
        print(f"Error: Manifest file not found at {csv_filepath}")
        return None
    except Exception as e:
        print(f"Error reading CSV file {csv_filepath}: {e}")
        return None
    print(f"Read {len(manifest_items)} valid items from manifest.")
    return manifest_items