"""
migrate_template.py
-------------------
End-to-end migration: downloads an Adobe Sign template, converts it to
DocuSign format, and uploads it to DocuSign.

Usage:
    python3 src/migrate_template.py --list
        Show all Adobe Sign templates available to download.

    python3 src/migrate_template.py --template "Template Name"
        Download, convert, and upload the named template.
        If multiple templates share the same name, the most recently modified
        one is used.

    python3 src/migrate_template.py --template "Template Name" --skip-upload
        Download and convert only — writes the DocuSign JSON to
        migration-output/ without uploading.
"""

import argparse
import os
import sys
from pathlib import Path

from dotenv import load_dotenv

load_dotenv()
sys.path.insert(0, os.path.dirname(__file__))

from adobe_api import adobe_api_get, adobe_api_get_bytes
from compose_docusign_template import compose_template
from upload_docusign_template import upload_template

DOWNLOADS_DIR = Path(__file__).parent.parent / "downloads"
OUTPUT_DIR = Path(__file__).parent.parent / "migration-output"


def safe_dirname(name):
    return "".join(c if c.isalnum() or c in " -_" else "_" for c in name).strip()


def save_json(path, data):
    import json
    with open(path, "w", encoding="utf-8") as f:
        json.dump(data, f, indent=2)


def fetch_template_list():
    result = adobe_api_get("libraryDocuments")
    return result.get("libraryDocumentList", [])


def cmd_list():
    print("Fetching template list from Adobe Sign...")
    templates = fetch_template_list()
    if not templates:
        print("No templates found.")
        return
    print(f"\n{'Name':<45} {'Modified':<25} {'ID'}")
    print("-" * 100)
    for t in sorted(templates, key=lambda x: x.get("modifiedDate", ""), reverse=True):
        print(f"{t['name']:<45} {t.get('modifiedDate', 'n/a'):<25} {t['id']}")


def find_template(template_name, templates):
    matches = [t for t in templates if t["name"] == template_name]
    if not matches:
        print(f"ERROR: No template named '{template_name}' found in Adobe Sign.")
        print("Run --list to see available templates.")
        sys.exit(1)
    if len(matches) > 1:
        print(f"  {len(matches)} templates named '{template_name}' — using most recently modified.")
    return max(matches, key=lambda t: t.get("modifiedDate", ""))


def download_template(template) -> Path:
    import json
    template_id = template["id"]
    template_name = template["name"]
    dir_name = f"{safe_dirname(template_name)}__{template_id[:8]}"
    out_dir = DOWNLOADS_DIR / dir_name
    out_dir.mkdir(parents=True, exist_ok=True)

    print(f"\nDownloading '{template_name}' → downloads/{dir_name}/")

    metadata = adobe_api_get(f"libraryDocuments/{template_id}")
    save_json(out_dir / "metadata.json", metadata)

    try:
        form_fields = adobe_api_get(f"libraryDocuments/{template_id}/formFields")
        save_json(out_dir / "form_fields.json", form_fields)
        field_count = len(form_fields.get("fields", []))
        print(f"  {field_count} form fields")
    except Exception as e:
        print(f"  WARNING: Could not fetch form fields: {e}")
        save_json(out_dir / "form_fields.json", {"error": str(e)})

    docs = adobe_api_get(f"libraryDocuments/{template_id}/documents")
    save_json(out_dir / "documents.json", docs)

    for doc in docs.get("documents", []):
        doc_id = doc["id"]
        doc_name = doc.get("name", doc_id)
        if not doc_name.lower().endswith(".pdf"):
            doc_name += ".pdf"
        safe_name = safe_dirname(doc_name)
        try:
            pdf_bytes = adobe_api_get_bytes(
                f"libraryDocuments/{template_id}/documents/{doc_id}"
            )
            with open(out_dir / safe_name, "wb") as f:
                f.write(pdf_bytes)
            print(f"  PDF ({len(pdf_bytes) // 1024}KB) → {safe_name}")
        except Exception as e:
            print(f"  WARNING: Could not download PDF: {e}")

    return out_dir


def convert_template(template_dir: Path) -> Path:
    output_path = OUTPUT_DIR / template_dir.name / "docusign-template.json"
    print(f"\nConverting to DocuSign format...")
    _, warnings, _ = compose_template(str(template_dir), str(output_path))
    print(f"  Written: {output_path}")
    for w in warnings:
        print(f"  WARNING: {w}")
    return output_path


def main():
    parser = argparse.ArgumentParser(
        description="Migrate an Adobe Sign template to DocuSign",
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog=__doc__,
    )
    group = parser.add_mutually_exclusive_group(required=True)
    group.add_argument(
        "--template", metavar="NAME",
        help="Name of the Adobe Sign template to migrate"
    )
    group.add_argument(
        "--list", action="store_true",
        help="List available Adobe Sign templates"
    )
    parser.add_argument(
        "--skip-upload", action="store_true",
        help="Convert only — do not upload to DocuSign"
    )
    args = parser.parse_args()

    DOWNLOADS_DIR.mkdir(exist_ok=True)
    OUTPUT_DIR.mkdir(exist_ok=True)

    if args.list:
        cmd_list()
        return

    templates = fetch_template_list()
    template = find_template(args.template, templates)
    template_dir = download_template(template)
    output_path = convert_template(template_dir)

    if args.skip_upload:
        print(f"\nSkipped upload. DocuSign JSON: {output_path}")
    else:
        print()
        upload_template(str(output_path))


if __name__ == "__main__":
    main()