#!/usr/bin/env python3
"""Generate a dedicated apps inventory CSV from Entra app exports."""

from __future__ import annotations

import argparse
import csv
import json
from pathlib import Path
from typing import Any


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--root", required=True, help="Path to the Entra workload backup root (tenant-state/entra).")
    parser.add_argument(
        "--output-dir",
        required=True,
        help="Directory where apps inventory report files will be written.",
    )
    parser.add_argument(
        "--output-name",
        default="apps-inventory.csv",
        help="Output CSV filename (default: apps-inventory.csv).",
    )
    return parser.parse_args()


def safe_text(value: object) -> str:
    if value is None:
        return ""
    return str(value).strip()


def summarize_owners(owners: object) -> tuple[int, str]:
    if not isinstance(owners, list):
        return 0, ""

    labels: list[str] = []
    for owner in owners:
        if not isinstance(owner, dict):
            continue
        label = (
            safe_text(owner.get("displayName"))
            or safe_text(owner.get("userPrincipalName"))
            or safe_text(owner.get("appId"))
            or safe_text(owner.get("id"))
            or "Unknown owner"
        )
        labels.append(label)

    return len(labels), "; ".join(labels)


def summarize_required_resource_access(entries: object) -> tuple[int, str]:
    if not isinstance(entries, list):
        return 0, ""

    summary: list[str] = []
    total_permissions = 0
    for entry in entries:
        if not isinstance(entry, dict):
            continue
        resource_name = safe_text(entry.get("resourceDisplayName")) or "Unresolved resource"
        resource_app_id = safe_text(entry.get("resourceAppId"))
        permissions = entry.get("permissions")
        permission_labels: list[str] = []
        if isinstance(permissions, list):
            for permission in permissions:
                if not isinstance(permission, dict):
                    continue
                total_permissions += 1
                perm_type = safe_text(permission.get("type")) or "UnknownType"
                perm_label = (
                    safe_text(permission.get("value"))
                    or safe_text(permission.get("displayName"))
                    or safe_text(permission.get("id"))
                    or "UnknownPermission"
                )
                permission_labels.append(f"{perm_label} [{perm_type}]")

        resource_label = resource_name
        if resource_app_id:
            resource_label += f" ({resource_app_id})"
        if permission_labels:
            summary.append(f"{resource_label}: {', '.join(permission_labels)}")
        else:
            summary.append(resource_label)

    return total_permissions, "; ".join(summary)


def summarize_enterprise_app_role_assignments(entries: object) -> tuple[int, str]:
    if not isinstance(entries, list):
        return 0, ""

    summary: list[str] = []
    count = 0
    for entry in entries:
        if not isinstance(entry, dict):
            continue
        count += 1
        resource_name = safe_text(entry.get("resourceDisplayName")) or "Unresolved resource"
        resource_id = safe_text(entry.get("resourceId"))
        role_name = (
            safe_text(entry.get("appRoleValue"))
            or safe_text(entry.get("appRoleDisplayName"))
            or safe_text(entry.get("appRoleId"))
            or "Default access"
        )
        label = resource_name
        if resource_id:
            label += f" ({resource_id})"
        summary.append(f"{label}: {role_name}")

    return count, "; ".join(summary)


def verified_publisher_label(value: object) -> str:
    if not isinstance(value, dict):
        return ""
    return (
        safe_text(value.get("displayName"))
        or safe_text(value.get("verifiedPublisherId"))
        or safe_text(value.get("addedDateTime"))
    )


def iter_exported_json(export_dir: Path) -> list[tuple[Path, dict[str, Any]]]:
    if not export_dir.exists():
        return []
    items: list[tuple[Path, dict[str, Any]]] = []
    for path in sorted(export_dir.rglob("*.json")):
        try:
            payload = json.loads(path.read_text(encoding="utf-8"))
        except Exception:
            continue
        if isinstance(payload, dict):
            items.append((path, payload))
    return items


def main() -> int:
    args = parse_args()
    root = Path(args.root).resolve()
    output_dir = Path(args.output_dir).resolve()
    output_path = output_dir / args.output_name

    if not root.exists():
        raise SystemExit(f"Backup path does not exist: {root}")

    app_reg_dir = root / "App Registrations"
    ent_apps_dir = root / "Enterprise Applications"

    app_reg_items = iter_exported_json(app_reg_dir)
    ent_app_items = iter_exported_json(ent_apps_dir)

    rows: list[dict[str, str]] = []

    for source_path, payload in app_reg_items:
        owner_count, owners = summarize_owners(payload.get("ownersResolved"))
        perm_count, permissions = summarize_required_resource_access(
            payload.get("requiredResourceAccessResolved")
        )
        rows.append(
            {
                "AppType": "AppRegistration",
                "DisplayName": safe_text(payload.get("displayName")) or source_path.stem,
                "ObjectId": safe_text(payload.get("id")),
                "AppId": safe_text(payload.get("appId")),
                "SignInAudience": safe_text(payload.get("signInAudience")),
                "ServicePrincipalType": "",
                "AccountEnabled": "",
                "PublisherDomain": safe_text(payload.get("publisherDomain")),
                "PublisherName": "",
                "VerifiedPublisher": verified_publisher_label(payload.get("verifiedPublisher")),
                "CreatedDateTime": safe_text(payload.get("createdDateTime")),
                "OwnersCount": str(owner_count),
                "OwnersResolved": owners,
                "ResolvedPermissionCount": str(perm_count),
                "ResolvedPermissions": permissions,
                "ResolvedAppRoleAssignmentCount": "0",
                "ResolvedAppRoleAssignments": "",
                "SourceFile": source_path.relative_to(root).as_posix(),
            }
        )

    for source_path, payload in ent_app_items:
        owner_count, owners = summarize_owners(payload.get("ownersResolved"))
        assignment_count, assignments = summarize_enterprise_app_role_assignments(
            payload.get("appRoleAssignmentsResolved")
        )
        rows.append(
            {
                "AppType": "EnterpriseApplication",
                "DisplayName": safe_text(payload.get("displayName")) or source_path.stem,
                "ObjectId": safe_text(payload.get("id")),
                "AppId": safe_text(payload.get("appId")),
                "SignInAudience": "",
                "ServicePrincipalType": safe_text(payload.get("servicePrincipalType")),
                "AccountEnabled": safe_text(payload.get("accountEnabled")),
                "PublisherDomain": "",
                "PublisherName": safe_text(payload.get("publisherName")),
                "VerifiedPublisher": verified_publisher_label(payload.get("verifiedPublisher")),
                "CreatedDateTime": "",
                "OwnersCount": str(owner_count),
                "OwnersResolved": owners,
                "ResolvedPermissionCount": "0",
                "ResolvedPermissions": "",
                "ResolvedAppRoleAssignmentCount": str(assignment_count),
                "ResolvedAppRoleAssignments": assignments,
                "SourceFile": source_path.relative_to(root).as_posix(),
            }
        )

    rows.sort(
        key=lambda row: (
            row["AppType"].lower(),
            row["DisplayName"].lower(),
            row["ObjectId"].lower(),
        )
    )

    output_dir.mkdir(parents=True, exist_ok=True)
    fieldnames = [
        "AppType",
        "DisplayName",
        "ObjectId",
        "AppId",
        "SignInAudience",
        "ServicePrincipalType",
        "AccountEnabled",
        "PublisherDomain",
        "PublisherName",
        "VerifiedPublisher",
        "CreatedDateTime",
        "OwnersCount",
        "OwnersResolved",
        "ResolvedPermissionCount",
        "ResolvedPermissions",
        "ResolvedAppRoleAssignmentCount",
        "ResolvedAppRoleAssignments",
        "SourceFile",
    ]
    with output_path.open("w", encoding="utf-8", newline="") as handle:
        writer = csv.DictWriter(handle, fieldnames=fieldnames)
        writer.writeheader()
        writer.writerows(rows)

    print(
        "Generated apps inventory report: "
        + f"{output_path} "
        + f"(rows={len(rows)}, appRegistrations={len(app_reg_items)}, enterpriseApps={len(ent_app_items)})"
    )
    return 0


if __name__ == "__main__":
    raise SystemExit(main())