import os
import sys
import xml.etree.ElementTree as ET

INDENT = "  "
NEWLINE = "\n"
OUTPUT_DIR = "C:/5/docs"

# TABLE DOCUMENTATION
def write_table_doc(table: ET.Element):
    table_name = table.get("Name")
    class_name = table.get("ClassName")
    comment = table.get("Comment", "")

    lines = []

    # HEADER
    lines.append(f"# {class_name or table_name}")
    lines.append("")

    if comment:
        lines.append(comment)
        lines.append("")

    lines.append(f"**Database table:** `{table_name}`")
    lines.append(f"**Model class:** `{class_name}`")
    lines.append("")

    # COLUMNS
    lines.append("## Fields")
    lines.append("")
    lines.append("| Field | Column | Type | Nullable | Description |")
    lines.append("|-------|--------|------|----------|-------------|")

    columns = {}
    for column in table.findall("Column"):
        col_name = column.get("Name")
        field_name = column.get("FieldName")
        db_type = column.get("DatabaseType")
        nullable = column.get("Nullable", "false").lower() == "true"
        comment = column.get("Comment", "")

        columns[col_name] = column

        lines.append(
            f"| {field_name} | {col_name} | {db_type} | {str(nullable)} | {comment} |"
        )

    lines.append("")
    return NEWLINE.join(lines)

# FOREIGN KEYS
def write_relations(table: ET.Element, table_files: dict):
    fks = table.findall("ForeignKey")
    if not fks:
        return ""

    lines = []
    lines.append("## Relations")
    lines.append("")

    for fk in fks:
        from_col = fk.get("FromColumn")
        to_class = fk.get("ToClassName")
        field_name = fk.get("FieldName")

        target_file = table_files.get(to_class, f"{to_class}.md")

        lines.append(
            f"- `{field_name}` → [{to_class}]({target_file}) via `{from_col}`"
        )

    lines.append("")
    return NEWLINE.join(lines)

# NAMED ROWS
def write_named_rows(table: ET.Element):
    named_rows = table.findall("NamedRow")
    if not named_rows:
        return ""

    lines = []
    lines.append("## Named Rows")
    lines.append("")

    all_rows = []
    columns = []
    seen = set()

    for nr in named_rows:
        attrib = nr.attrib
        if not attrib:
            continue

        all_rows.append(attrib)

        for k in attrib.keys():
            if k not in seen:
                seen.add(k)
                columns.append(k)

    if not all_rows:
        return ""

    lines.append("| " + " | ".join(columns) + " |")
    lines.append("| " + " | ".join(["---"] * len(columns)) + " |")

    for r in all_rows:
        lines.append("| " + " | ".join(r.get(c, "") for c in columns) + " |")

    lines.append("")

    return NEWLINE.join(lines)

def ensure_dir(path):
    os.makedirs(path, exist_ok=True)

xml_data = sys.stdin.read()
tree = ET.ElementTree(ET.fromstring(xml_data))
root = tree.getroot()

output_dir = os.path.abspath(OUTPUT_DIR)
ensure_dir(output_dir)

table_files = {}
index_lines = []
index_lines.append("# Database Documentation")
index_lines.append("")
index_lines.append("## Tables")
index_lines.append("")

for db in root.findall("Database"):
    for schema in db.findall("Schema"):
        for table in schema.findall("Table"):
            table_name = table.get("Name")
            class_name = table.get("ClassName")

            file_name = f"{class_name or table_name}.md"
            table_files[class_name or table_name] = file_name
            file_path = os.path.join(output_dir, "entities", file_name)

            ensure_dir(os.path.dirname(file_path))

            md = write_table_doc(table)
            md += write_relations(table, table_files)
            md += write_named_rows(table)
            with open(file_path, "w", encoding="utf-8") as f:
                f.write(md)

            index_lines.append(f"- [{class_name or table_name}](entities/{file_name})")

# write index
with open(os.path.join(output_dir, "index.md"), "w", encoding="utf-8") as f:
    f.write(NEWLINE.join(index_lines))