# core/bulk_importer.py
import re
from database.connection import get_connection
from docling.document_converter import DocumentConverter

class BulkImporter:
    def __init__(self):
        self.converter = DocumentConverter()
        self.unit_regex = re.compile(r'U([0-9]+)')

    def clean_field(self, text: str) -> str:
        """Removes layout spacing, structural artifacts, and noise."""
        if not text:
            return ""
        # Remove markdown bold/italics markers if any, and compress spaces
        cleaned = text.replace('*', '').replace('_', '').replace('\\', '')
        cleaned = re.sub(r'\s+', ' ', cleaned)
        return cleaned.strip()

    def parse_unit(self, context_str: str) -> int:
        """Extracts the integer unit ID out of strings like 'U3_8B' or 'U7'."""
        match = self.unit_regex.search(context_str)
        if match:
            return int(match.group(1))
        return None

    def insert_pair(self, cursor, es_text, en_text, context_tag, textbook_name):
        """Helper to cleanly insert a single Spanish-English translation pair."""
        es_clean = self.clean_field(es_text)
        en_clean = self.clean_field(en_text)
        tag_clean = self.clean_field(context_tag)
        
        # Guard clause against column headers or empty layout cells
        if not es_clean or not en_clean:
            return False
        if es_clean.lower() in ["spanish", "word", "alphabetical glossary", "es", "en"] or len(es_clean) <= 1:
            return False

        unit_number = self.parse_unit(tag_clean)

        try:
            # 1. Insert Spanish Phrase
            cursor.execute("""
                INSERT INTO phrases (text, language, textbook, unit, source_context)
                VALUES (?, 'es', ?, ?, ?)
            """, (es_clean, textbook_name, unit_number, tag_clean))
            es_id = cursor.lastrowid

            # 2. Insert English Translation
            cursor.execute("""
                INSERT INTO phrases (text, language, textbook, unit, source_context)
                VALUES (?, 'en', ?, ?, ?)
            """, (en_clean, textbook_name, unit_number, tag_clean))
            en_id = cursor.lastrowid

            # 3. Create Bidirectional Cross-Reference Entries
            cursor.execute("INSERT INTO translations (source_phrase_id, target_phrase_id) VALUES (?, ?)", (es_id, en_id))
            cursor.execute("INSERT INTO translations (source_phrase_id, target_phrase_id) VALUES (?, ?)", (en_id, es_id))
            return True
        except Exception:
            return False

    def import_pdf_glossary(self, file_path: str, textbook_name: str):
        print(f"🔄 Docling is analyzing structural layout for '{file_path}'...")
        
        try:
            result = self.converter.convert(file_path)
            document_text = result.document.export_to_markdown()
        except Exception as e:
            print(f"❌ Docling processing failed: {e}")
            return 0

        conn = get_connection()
        cursor = conn.cursor()
        
        print("📥 Parsing 6-column text grid structure and writing to database...")
        count = 0

        # Process the markdown line-by-line
        lines = document_text.split('\n')
        for line in lines:
            line_str = line.strip()
            
            # Target lines containing table formatting row data
            if not line_str.startswith('|') or not line_str.endswith('|'):
                continue
                
            # Split by markdown table pipes
            # e.g., "| años60 m | 1960s | U8_7A | bañ osmpl | bath | U1_1A |"
            parts = [p.strip() for p in line_str.split('|')]
            
            # A valid row split will include empty items at the ends due to leading/trailing pipes
            # For a 6-column table, len(parts) should be at least 8 elements
            if len(parts) < 7:
                continue
                
            # Skip Markdown table header separator rows: |---|---|...
            if '---' in parts[1]:
                continue

            # Extract Left-Hand Column Group (Columns 1, 2, 3)
            es_left = parts[1]
            en_left = parts[2]
            unit_left = parts[3] if len(parts) >= 4 else ""
            
            if self.insert_pair(cursor, es_left, en_left, unit_left, textbook_name):
                count += 1

            # Extract Right-Hand Column Group (Columns 4, 5, 6)
            if len(parts) >= 7:
                es_right = parts[4]
                en_right = parts[5]
                unit_right = parts[6]
                
                if self.insert_pair(cursor, es_right, en_right, unit_right, textbook_name):
                    count += 1

        conn.commit()
        conn.close()
        print(f"🎉 Bulk ingestion complete! Registered {count} matched glossary items.")
        return count