#!/usr/bin/env python3
"""
PP-StructureV3 Line Items Extraction POC

Tests line items extraction from Swedish invoices using PP-StructureV3.
Parses HTML table structure to extract structured line item data.

Run with invoice-sm120 conda environment.
"""

import sys
import re
from pathlib import Path
from html.parser import HTMLParser
from dataclasses import dataclass

# Add project root to path
project_root = Path(__file__).parent.parent
sys.path.insert(0, str(project_root / "packages" / "backend"))

from paddleocr import PPStructureV3
import fitz  # PyMuPDF


@dataclass
class LineItem:
    """Single line item from invoice."""
    row_index: int
    article_number: str | None
    description: str | None
    quantity: str | None
    unit: str | None
    unit_price: str | None
    amount: str | None
    vat_rate: str | None
    confidence: float = 0.9


class TableHTMLParser(HTMLParser):
    """Parse HTML table into rows and cells."""

    def __init__(self):
        super().__init__()
        self.rows: list[list[str]] = []
        self.current_row: list[str] = []
        self.current_cell: str = ""
        self.in_td = False
        self.in_thead = False
        self.header_row: list[str] = []

    def handle_starttag(self, tag, attrs):
        if tag == "tr":
            self.current_row = []
        elif tag in ("td", "th"):
            self.in_td = True
            self.current_cell = ""
        elif tag == "thead":
            self.in_thead = True

    def handle_endtag(self, tag):
        if tag in ("td", "th"):
            self.in_td = False
            self.current_row.append(self.current_cell.strip())
        elif tag == "tr":
            if self.current_row:
                if self.in_thead:
                    self.header_row = self.current_row
                else:
                    self.rows.append(self.current_row)
        elif tag == "thead":
            self.in_thead = False

    def handle_data(self, data):
        if self.in_td:
            self.current_cell += data


# Swedish column name mappings
# Note: Some headers may contain multiple column names merged together
COLUMN_MAPPINGS = {
    'article_number': ['art nummer', 'artikelnummer', 'artikel', 'artnr', 'art.nr', 'art nr'],
    'description': ['beskrivning', 'produktbeskrivning', 'produkt', 'tjänst', 'text', 'benämning', 'vara/tjänst', 'vara'],
    'quantity': ['antal', 'qty', 'st', 'pcs', 'kvantitet'],
    'unit': ['enhet', 'unit'],
    'unit_price': ['á-pris', 'a-pris', 'pris', 'styckpris', 'enhetspris', 'à pris'],
    'amount': ['belopp', 'summa', 'total', 'netto', 'rad summa'],
    'vat_rate': ['moms', 'moms%', 'vat', 'skatt', 'moms %'],
}


def normalize_header(header: str) -> str:
    """Normalize header text for matching."""
    return header.lower().strip().replace(".", "").replace("-", " ")


def map_columns(headers: list[str]) -> dict[int, str]:
    """Map column indices to field names."""
    mapping = {}
    for idx, header in enumerate(headers):
        normalized = normalize_header(header)

        # Skip empty headers
        if not normalized.strip():
            continue

        best_match = None
        best_match_len = 0

        for field, patterns in COLUMN_MAPPINGS.items():
            for pattern in patterns:
                # Require exact match or pattern must be a significant portion
                if pattern == normalized:
                    # Exact match - use immediately
                    best_match = field
                    best_match_len = len(pattern) + 100  # Prioritize exact
                    break
                elif pattern in normalized and len(pattern) > best_match_len:
                    # Pattern found in header - use longer matches
                    if len(pattern) >= 3:  # Minimum pattern length
                        best_match = field
                        best_match_len = len(pattern)

            if best_match_len > 100:  # Was exact match
                break

        if best_match:
            mapping[idx] = best_match

    return mapping


def parse_table_html(html: str) -> tuple[list[str], list[list[str]]]:
    """Parse HTML table and return header and rows."""
    parser = TableHTMLParser()
    parser.feed(html)
    return parser.header_row, parser.rows


def detect_header_row(rows: list[list[str]]) -> tuple[int, list[str], bool]:
    """
    Detect which row is the header based on content patterns.

    Returns (header_row_index, header_row, is_at_end).
    is_at_end indicates if header is at the end (table is reversed).
    Returns (-1, [], False) if no header detected.
    """
    header_keywords = set()
    for patterns in COLUMN_MAPPINGS.values():
        for p in patterns:
            header_keywords.add(p.lower())

    best_match = (-1, [], 0)

    for i, row in enumerate(rows):
        # Skip empty rows
        if all(not cell.strip() for cell in row):
            continue

        # Check if row contains header keywords
        row_text = " ".join(cell.lower() for cell in row)
        matches = sum(1 for kw in header_keywords if kw in row_text)

        # Track the best match
        if matches > best_match[2]:
            best_match = (i, row, matches)

    if best_match[2] >= 2:
        header_idx = best_match[0]
        is_at_end = header_idx == len(rows) - 1 or header_idx > len(rows) // 2
        return header_idx, best_match[1], is_at_end

    return -1, [], False


def extract_line_items(html: str) -> list[LineItem]:
    """Extract line items from HTML table."""
    header, rows = parse_table_html(html)

    is_reversed = False
    if not header:
        # Try to detect header row from content
        header_idx, detected_header, is_at_end = detect_header_row(rows)
        if header_idx >= 0:
            header = detected_header
            if is_at_end:
                # Header is at the end - table is reversed
                is_reversed = True
                rows = rows[:header_idx]  # Data rows are before header
            else:
                rows = rows[header_idx + 1:]  # Data rows start after header
        elif rows:
            # Fall back to first non-empty row
            for i, row in enumerate(rows):
                if any(cell.strip() for cell in row):
                    header = row
                    rows = rows[i + 1:]
                    break

    column_map = map_columns(header)

    items = []
    for row_idx, row in enumerate(rows):
        item_data = {
            'row_index': row_idx,
            'article_number': None,
            'description': None,
            'quantity': None,
            'unit': None,
            'unit_price': None,
            'amount': None,
            'vat_rate': None,
        }

        for col_idx, cell in enumerate(row):
            if col_idx in column_map:
                field = column_map[col_idx]
                item_data[field] = cell if cell else None

        # Only add if we have at least description or amount
        if item_data['description'] or item_data['amount']:
            items.append(LineItem(**item_data))

    return items


def render_pdf_to_image(pdf_path: str, dpi: int = 200) -> bytes:
    """Render first page of PDF to image bytes."""
    doc = fitz.open(pdf_path)
    page = doc[0]
    mat = fitz.Matrix(dpi / 72, dpi / 72)
    pix = page.get_pixmap(matrix=mat)
    img_bytes = pix.tobytes("png")
    doc.close()
    return img_bytes


def test_line_items_extraction(pdf_path: str) -> dict:
    """Test line items extraction on a PDF."""
    print(f"\n{'='*70}")
    print(f"Testing Line Items Extraction: {Path(pdf_path).name}")
    print(f"{'='*70}")

    # Render PDF to image
    print("Rendering PDF to image...")
    img_bytes = render_pdf_to_image(pdf_path)

    # Save temp image
    temp_img_path = "/tmp/test_invoice.png"
    with open(temp_img_path, "wb") as f:
        f.write(img_bytes)

    # Initialize PP-StructureV3
    print("Initializing PP-StructureV3...")
    pipeline = PPStructureV3(
        device="gpu:0",
        use_doc_orientation_classify=False,
        use_doc_unwarping=False,
    )

    # Run detection
    print("Running table detection...")
    results = pipeline.predict(temp_img_path)

    all_line_items = []
    table_details = []

    for result in results if results else []:
        table_res_list = result.get("table_res_list") if hasattr(result, "get") else None

        if table_res_list:
            print(f"\nFound {len(table_res_list)} tables")

            for i, table_res in enumerate(table_res_list):
                html = table_res.get("pred_html", "")
                ocr_pred = table_res.get("table_ocr_pred", {})

                print(f"\n--- Table {i+1} ---")

                # Debug: show full HTML for first table
                if i == 0:
                    print(f"  Full HTML:\n{html}")

                # Debug: inspect table_ocr_pred structure
                if isinstance(ocr_pred, dict):
                    print(f"  table_ocr_pred keys: {list(ocr_pred.keys())}")
                    # Check if rec_texts exists (actual OCR text)
                    if "rec_texts" in ocr_pred:
                        texts = ocr_pred["rec_texts"]
                        print(f"  OCR texts count: {len(texts)}")
                        print(f"  Sample OCR texts: {texts[:5]}")
                elif isinstance(ocr_pred, list):
                    print(f"  table_ocr_pred is list with {len(ocr_pred)} items")
                    if ocr_pred:
                        print(f"  First item type: {type(ocr_pred[0])}")
                        print(f"  First few items: {ocr_pred[:3]}")

                # Parse HTML
                header, rows = parse_table_html(html)
                print(f"  HTML Header (from thead): {header}")
                print(f"  HTML Rows: {len(rows)}")

                # Try to detect header if not in thead
                detected_header = None
                is_reversed = False
                if not header and rows:
                    header_idx, detected_header, is_at_end = detect_header_row(rows)
                    if header_idx >= 0:
                        is_reversed = is_at_end
                        print(f"  Detected header at row {header_idx}: {detected_header}")
                        print(f"  Table is {'REVERSED (header at bottom)' if is_reversed else 'normal'}")
                        header = detected_header

                if rows:
                    print(f"  First row: {rows[0]}")
                    if len(rows) > 1:
                        print(f"  Second row: {rows[1]}")

                # Check if this looks like a line items table
                column_map = map_columns(header) if header else {}
                print(f"  Column mapping: {column_map}")

                is_line_items_table = (
                    'description' in column_map.values() or
                    'amount' in column_map.values() or
                    'article_number' in column_map.values()
                )

                if is_line_items_table:
                    print(f"  >>> This appears to be a LINE ITEMS table!")
                    items = extract_line_items(html)
                    print(f"  Extracted {len(items)} line items:")
                    for item in items:
                        print(f"    - {item.description}: {item.quantity} x {item.unit_price} = {item.amount}")
                    all_line_items.extend(items)
                else:
                    print(f"  >>> This is NOT a line items table (summary/payment)")

                table_details.append({
                    "index": i,
                    "header": header,
                    "row_count": len(rows),
                    "is_line_items": is_line_items_table,
                    "column_map": column_map,
                })

    print(f"\n{'='*70}")
    print(f"EXTRACTION SUMMARY")
    print(f"{'='*70}")
    print(f"Total tables: {len(table_details)}")
    print(f"Line items tables: {sum(1 for t in table_details if t['is_line_items'])}")
    print(f"Total line items: {len(all_line_items)}")

    return {
        "pdf": pdf_path,
        "tables": table_details,
        "line_items": all_line_items,
    }


def main():
    import argparse
    parser = argparse.ArgumentParser(description="Test line items extraction")
    parser.add_argument("--pdf", type=str, help="Path to PDF file")
    args = parser.parse_args()

    if args.pdf:
        # Test specific PDF
        pdf_path = Path(args.pdf)
        if not pdf_path.exists():
            # Try relative to project root
            pdf_path = project_root / args.pdf
        if not pdf_path.exists():
            print(f"PDF not found: {args.pdf}")
            return
        test_line_items_extraction(str(pdf_path))
    else:
        # Test default invoice
        default_pdf = project_root / "exampl" / "Faktura54011.pdf"
        if default_pdf.exists():
            test_line_items_extraction(str(default_pdf))
        else:
            print(f"Default PDF not found: {default_pdf}")
            print("Usage: python ppstructure_line_items_poc.py --pdf <path>")


if __name__ == "__main__":
    main()