"""Registered project source metadata and refresh helpers."""

from __future__ import annotations

import json
import tempfile
from dataclasses import asdict, dataclass
from pathlib import Path

import atocore.config as _config
from atocore.ingestion.pipeline import ingest_folder


@dataclass(frozen=True)
class ProjectSourceRef:
    source: str
    subpath: str
    label: str = ""


@dataclass(frozen=True)
class RegisteredProject:
    project_id: str
    aliases: tuple[str, ...]
    description: str
    ingest_roots: tuple[ProjectSourceRef, ...]


def get_project_registry_template() -> dict:
    """Return a minimal template for registering a new project."""
    return {
        "projects": [
            {
                "id": "p07-example",
                "aliases": ["p07", "example-project"],
                "description": "Short description of the project and staged corpus.",
                "ingest_roots": [
                    {
                        "source": "vault",
                        "subpath": "incoming/projects/p07-example",
                        "label": "Primary staged project docs",
                    }
                ],
            }
        ]
    }


def build_project_registration_proposal(
    project_id: str,
    aliases: list[str] | tuple[str, ...] | None = None,
    description: str = "",
    ingest_roots: list[dict] | tuple[dict, ...] | None = None,
) -> dict:
    """Build a normalized project registration proposal without mutating state."""
    normalized_id = project_id.strip()
    if not normalized_id:
        raise ValueError("Project id must be non-empty")

    normalized_aliases = _normalize_aliases(aliases or [])
    normalized_roots = _normalize_ingest_roots(ingest_roots or [])
    if not normalized_roots:
        raise ValueError("At least one ingest root is required")

    collisions = _find_name_collisions(normalized_id, normalized_aliases)
    resolved_roots = []
    for root in normalized_roots:
        source_ref = ProjectSourceRef(
            source=root["source"],
            subpath=root["subpath"],
            label=root.get("label", ""),
        )
        resolved_path = _resolve_ingest_root(source_ref)
        resolved_roots.append(
            {
                **root,
                "path": str(resolved_path),
                "exists": resolved_path.exists(),
                "is_dir": resolved_path.is_dir(),
            }
        )

    return {
        "project": {
            "id": normalized_id,
            "aliases": normalized_aliases,
            "description": description.strip(),
            "ingest_roots": normalized_roots,
        },
        "resolved_ingest_roots": resolved_roots,
        "collisions": collisions,
        "registry_path": str(_config.settings.resolved_project_registry_path),
        "valid": not collisions,
    }


def register_project(
    project_id: str,
    aliases: list[str] | tuple[str, ...] | None = None,
    description: str = "",
    ingest_roots: list[dict] | tuple[dict, ...] | None = None,
) -> dict:
    """Persist a validated project registration to the registry file."""
    proposal = build_project_registration_proposal(
        project_id=project_id,
        aliases=aliases,
        description=description,
        ingest_roots=ingest_roots,
    )
    if not proposal["valid"]:
        collision_names = ", ".join(collision["name"] for collision in proposal["collisions"])
        raise ValueError(f"Project registration has collisions: {collision_names}")

    registry_path = _config.settings.resolved_project_registry_path
    payload = _load_registry_payload(registry_path)
    payload.setdefault("projects", []).append(proposal["project"])
    _write_registry_payload(registry_path, payload)

    return {
        **proposal,
        "status": "registered",
    }


def update_project(
    project_name: str,
    aliases: list[str] | tuple[str, ...] | None = None,
    description: str | None = None,
    ingest_roots: list[dict] | tuple[dict, ...] | None = None,
) -> dict:
    """Update an existing project registration in the registry file."""
    existing = get_registered_project(project_name)
    if existing is None:
        raise ValueError(f"Unknown project: {project_name}")

    final_aliases = _normalize_aliases(aliases) if aliases is not None else list(existing.aliases)
    final_description = description.strip() if description is not None else existing.description
    final_roots = (
        _normalize_ingest_roots(ingest_roots)
        if ingest_roots is not None
        else [asdict(root) for root in existing.ingest_roots]
    )
    if not final_roots:
        raise ValueError("At least one ingest root is required")

    collisions = _find_name_collisions(
        existing.project_id,
        final_aliases,
        exclude_project_id=existing.project_id,
    )
    if collisions:
        collision_names = ", ".join(collision["name"] for collision in collisions)
        raise ValueError(f"Project update has collisions: {collision_names}")

    updated_entry = {
        "id": existing.project_id,
        "aliases": final_aliases,
        "description": final_description,
        "ingest_roots": final_roots,
    }

    resolved_roots = []
    for root in final_roots:
        source_ref = ProjectSourceRef(
            source=root["source"],
            subpath=root["subpath"],
            label=root.get("label", ""),
        )
        resolved_path = _resolve_ingest_root(source_ref)
        resolved_roots.append(
            {
                **root,
                "path": str(resolved_path),
                "exists": resolved_path.exists(),
                "is_dir": resolved_path.is_dir(),
            }
        )

    registry_path = _config.settings.resolved_project_registry_path
    payload = _load_registry_payload(registry_path)
    payload["projects"] = [
        updated_entry if str(entry.get("id", "")).strip() == existing.project_id else entry
        for entry in payload.get("projects", [])
    ]
    _write_registry_payload(registry_path, payload)

    return {
        "project": updated_entry,
        "resolved_ingest_roots": resolved_roots,
        "collisions": [],
        "registry_path": str(registry_path),
        "valid": True,
        "status": "updated",
    }


def load_project_registry() -> list[RegisteredProject]:
    """Load project registry entries from JSON config."""
    registry_path = _config.settings.resolved_project_registry_path
    payload = _load_registry_payload(registry_path)
    entries = payload.get("projects", [])
    projects: list[RegisteredProject] = []

    for entry in entries:
        project_id = str(entry["id"]).strip()
        if not project_id:
            raise ValueError("Project registry entry is missing a non-empty id")
        aliases = tuple(
            alias.strip()
            for alias in entry.get("aliases", [])
            if isinstance(alias, str) and alias.strip()
        )
        description = str(entry.get("description", "")).strip()
        ingest_roots = tuple(
            ProjectSourceRef(
                source=str(root["source"]).strip(),
                subpath=str(root["subpath"]).strip(),
                label=str(root.get("label", "")).strip(),
            )
            for root in entry.get("ingest_roots", [])
            if str(root.get("source", "")).strip()
            and str(root.get("subpath", "")).strip()
        )
        if not ingest_roots:
            raise ValueError(f"Project registry entry '{project_id}' has no ingest_roots")
        projects.append(
            RegisteredProject(
                project_id=project_id,
                aliases=aliases,
                description=description,
                ingest_roots=ingest_roots,
            )
        )

    _validate_unique_project_names(projects)
    return projects


def list_registered_projects() -> list[dict]:
    """Return registry entries with resolved source readiness."""
    return [_project_to_dict(project) for project in load_project_registry()]


def get_registered_project(project_name: str) -> RegisteredProject | None:
    """Resolve a registry entry by id or alias."""
    needle = project_name.strip().lower()
    if not needle:
        return None

    for project in load_project_registry():
        candidates = {project.project_id.lower(), *(alias.lower() for alias in project.aliases)}
        if needle in candidates:
            return project
    return None


def resolve_project_name(name: str | None) -> str:
    """Canonicalize a project name through the registry.

    Returns the canonical ``project_id`` if the input matches any
    registered project's id or alias. Returns the input unchanged
    when it's empty or not in the registry — the second case keeps
    backwards compatibility with hand-curated state, memories, and
    interactions that predate the registry, or for projects that
    are intentionally not registered.

    This helper is the single canonicalization boundary for project
    names across the trust hierarchy. Every read/write that takes a
    project name should pass it through ``resolve_project_name``
    before storing or querying. The contract is documented in
    ``docs/architecture/representation-authority.md``.
    """
    if not name:
        return name or ""
    project = get_registered_project(name)
    if project is not None:
        return project.project_id
    return name


def refresh_registered_project(project_name: str, purge_deleted: bool = False) -> dict:
    """Ingest all configured source roots for a registered project.

    The returned dict carries an overall ``status`` so callers can tell at a
    glance whether the refresh was fully successful, partial, or did nothing
    at all because every configured root was missing or not a directory:

    - ``ingested``: every root was a real directory and was ingested
    - ``partial``:  at least one root ingested and at least one was unusable
    - ``nothing_to_ingest``: no roots were usable
    """
    project = get_registered_project(project_name)
    if project is None:
        raise ValueError(f"Unknown project: {project_name}")

    roots = []
    ingested_count = 0
    skipped_count = 0
    for source_ref in project.ingest_roots:
        resolved = _resolve_ingest_root(source_ref)
        root_result = {
            "source": source_ref.source,
            "subpath": source_ref.subpath,
            "label": source_ref.label,
            "path": str(resolved),
        }
        if not resolved.exists():
            roots.append({**root_result, "status": "missing"})
            skipped_count += 1
            continue
        if not resolved.is_dir():
            roots.append({**root_result, "status": "not_directory"})
            skipped_count += 1
            continue

        roots.append(
            {
                **root_result,
                "status": "ingested",
                "results": ingest_folder(resolved, purge_deleted=purge_deleted),
            }
        )
        ingested_count += 1

    if ingested_count == 0:
        overall_status = "nothing_to_ingest"
    elif skipped_count == 0:
        overall_status = "ingested"
    else:
        overall_status = "partial"

    return {
        "project": project.project_id,
        "aliases": list(project.aliases),
        "description": project.description,
        "purge_deleted": purge_deleted,
        "status": overall_status,
        "roots_ingested": ingested_count,
        "roots_skipped": skipped_count,
        "roots": roots,
    }


def _normalize_aliases(aliases: list[str] | tuple[str, ...]) -> list[str]:
    deduped: list[str] = []
    seen: set[str] = set()
    for alias in aliases:
        candidate = alias.strip()
        if not candidate:
            continue
        key = candidate.lower()
        if key in seen:
            continue
        seen.add(key)
        deduped.append(candidate)
    return deduped


def _normalize_ingest_roots(ingest_roots: list[dict] | tuple[dict, ...]) -> list[dict]:
    normalized: list[dict] = []
    for root in ingest_roots:
        source = str(root.get("source", "")).strip()
        subpath = str(root.get("subpath", "")).strip()
        label = str(root.get("label", "")).strip()
        if not source or not subpath:
            continue
        if source not in {"vault", "drive"}:
            raise ValueError(f"Unsupported source root: {source}")
        normalized.append({"source": source, "subpath": subpath, "label": label})
    return normalized


def _project_to_dict(project: RegisteredProject) -> dict:
    return {
        "id": project.project_id,
        "aliases": list(project.aliases),
        "description": project.description,
        "ingest_roots": [
            {
                **asdict(source_ref),
                "path": str(_resolve_ingest_root(source_ref)),
                "exists": _resolve_ingest_root(source_ref).exists(),
                "is_dir": _resolve_ingest_root(source_ref).is_dir(),
            }
            for source_ref in project.ingest_roots
        ],
    }


def _resolve_ingest_root(source_ref: ProjectSourceRef) -> Path:
    base_map = {
        "vault": _config.settings.resolved_vault_source_dir,
        "drive": _config.settings.resolved_drive_source_dir,
    }
    try:
        base_dir = base_map[source_ref.source]
    except KeyError as exc:
        raise ValueError(f"Unsupported source root: {source_ref.source}") from exc

    return (base_dir / source_ref.subpath).resolve(strict=False)


def _validate_unique_project_names(projects: list[RegisteredProject]) -> None:
    seen: dict[str, str] = {}
    for project in projects:
        names = [project.project_id, *project.aliases]
        for name in names:
            key = name.lower()
            if key in seen and seen[key] != project.project_id:
                raise ValueError(
                    f"Project registry name collision: '{name}' is used by both "
                    f"'{seen[key]}' and '{project.project_id}'"
                )
            seen[key] = project.project_id


def _find_name_collisions(
    project_id: str,
    aliases: list[str],
    exclude_project_id: str | None = None,
) -> list[dict]:
    collisions: list[dict] = []
    existing = load_project_registry()
    requested_names = [project_id, *aliases]
    for requested in requested_names:
        requested_key = requested.lower()
        for project in existing:
            if exclude_project_id is not None and project.project_id == exclude_project_id:
                continue
            project_names = [project.project_id, *project.aliases]
            if requested_key in {name.lower() for name in project_names}:
                collisions.append(
                    {
                        "name": requested,
                        "existing_project": project.project_id,
                    }
                )
                break
    return collisions


def _load_registry_payload(registry_path: Path) -> dict:
    if not registry_path.exists():
        return {"projects": []}
    return json.loads(registry_path.read_text(encoding="utf-8"))


def _write_registry_payload(registry_path: Path, payload: dict) -> None:
    registry_path.parent.mkdir(parents=True, exist_ok=True)
    rendered = json.dumps(payload, indent=2, ensure_ascii=True) + "\n"
    with tempfile.NamedTemporaryFile(
        mode="w",
        encoding="utf-8",
        dir=registry_path.parent,
        prefix=f"{registry_path.stem}.",
        suffix=".tmp",
        delete=False,
    ) as tmp_file:
        tmp_file.write(rendered)
        temp_path = Path(tmp_file.name)
    temp_path.replace(registry_path)