"""Construccion del payload final que se envia a Metabase.

Toma el YAML de un item local (con _meta + _refs + payload) y devuelve el
payload listo para POST/PUT, con slugs reemplazados por IDs reales del index.

Funciones puras — sin red, sin escritura, deterministicas.
"""

from __future__ import annotations

import copy
from pathlib import Path
from typing import Any

import yaml


# ---------------------------------------------------------------- Carga de YAMLs


def load_item_yaml(path: Path) -> dict:
    """Lee un YAML de item (card/dashboard/database/collection)."""
    with path.open() as f:
        doc = yaml.safe_load(f) or {}
    if not isinstance(doc, dict):
        raise ValueError(f"{path}: contenido no es un dict YAML")
    for key in ("_meta", "_refs", "payload"):
        if key not in doc:
            raise ValueError(f"{path}: falta bloque '{key}'")
    return doc


def assert_meta(doc: dict, expected_kind: str, expected_slug: str, path: Path) -> None:
    """Aborta si _meta no coincide con kind/slug esperados (regla R9)."""
    meta = doc.get("_meta", {})
    if meta.get("kind") != expected_kind:
        raise ValueError(
            f"{path}: _meta.kind='{meta.get('kind')}' pero esperaba '{expected_kind}'"
        )
    if meta.get("slug") != expected_slug:
        raise ValueError(
            f"{path}: _meta.slug='{meta.get('slug')}' pero esperaba '{expected_slug}'"
        )


def assert_id_matches_index(doc: dict, kind: str, slug: str, index: dict, path: Path) -> None:
    """Aborta si _meta.id difiere del id del index (regla R11)."""
    meta_id = doc.get("_meta", {}).get("id")
    idx_id = index.get(kind + "s", {}).get(slug)  # cards/dashboards/...
    if meta_id is None and idx_id is None:
        return  # item nuevo, no hay id que comparar
    if meta_id != idx_id:
        raise ValueError(
            f"{path}: _meta.id={meta_id} no coincide con index ({idx_id}). "
            f"Posible YAML duplicado con slug renombrado pero id sin actualizar."
        )


# ---------------------------------------------------------------- Resolucion de refs


def _resolve_slug(slug: str | None, kind_plural: str, index: dict) -> int | None:
    """Slug -> id Metabase. None -> None. Slug desconocido -> ValueError."""
    if slug is None:
        return None
    mapping = index.get(kind_plural, {})
    if slug not in mapping:
        raise ValueError(
            f"slug '{slug}' (tipo {kind_plural}) no existe en index. "
            f"Conocidos: {sorted(mapping.keys())}"
        )
    return mapping[slug]


# ---------------------------------------------------------------- Builders por kind


def build_card_payload(doc: dict, index: dict) -> dict:
    """Resuelve refs y devuelve el payload listo para POST/PUT a /api/card.

    Sin lecturas de Metabase. Sin merges con estado remoto. Solo lo que
    tiene el YAML (regla R8).
    """
    refs = doc.get("_refs", {}) or {}
    payload = copy.deepcopy(doc.get("payload", {}) or {})

    # database (obligatorio en cards)
    db_slug = refs.get("database")
    if db_slug is None:
        raise ValueError("card payload: falta _refs.database")
    db_id = _resolve_slug(db_slug, "databases", index)
    payload["database_id"] = db_id

    # dataset_query.database (mismo id, tambien debe ir resuelto)
    dq = payload.get("dataset_query")
    if isinstance(dq, dict) and "database" in dq:
        dq["database"] = db_id

    # collection (opcional; puede ser None = root)
    if "collection" in refs:
        coll_slug = refs["collection"]
        payload["collection_id"] = _resolve_slug(coll_slug, "collections", index)

    return payload


def build_dashboard_payload(doc: dict, index: dict) -> dict:
    """Resuelve refs y devuelve el payload listo para POST/PUT a /api/dashboard.

    Para dashcards: cada `card` slug -> `card_id` int. Series tambien.
    Mantiene la lista de dashcards COMPLETA tal como esta en el YAML
    (Metabase la trata como estado deseado).

    Auto-inyeccion para dashcards nuevas (sin `id`):
      - `id`: asigna negativo unico (-1, -2, ...) en orden de aparicion.
      - `visualization_settings`: {} si falta.
      - `parameter_mappings`: [] si falta.
    Si la dashcard ya trae `id` (positivo o negativo), no se toca.
    """
    refs = doc.get("_refs", {}) or {}
    payload = copy.deepcopy(doc.get("payload", {}) or {})

    # collection (opcional)
    if "collection" in refs:
        coll_slug = refs["collection"]
        payload["collection_id"] = _resolve_slug(coll_slug, "collections", index)

    # dashcards: card slug -> card_id int + auto-inyeccion de campos nuevos
    dashcards = payload.get("dashcards", []) or []
    new_dashcards = []
    next_neg_id = -1  # contador de ids negativos auto-asignados
    used_neg_ids = {dc["id"] for dc in dashcards if isinstance(dc.get("id"), int) and dc["id"] < 0}
    for i, dc in enumerate(dashcards):
        dc = dict(dc)
        card_slug = dc.pop("card", None)
        if card_slug is not None:
            try:
                dc["card_id"] = _resolve_slug(card_slug, "cards", index)
            except ValueError as e:
                raise ValueError(f"dashcard #{i}: {e}") from None
        # series: lista de slugs -> lista de {id}
        series_slugs = dc.get("series") or []
        if series_slugs:
            dc["series"] = [
                {"id": _resolve_slug(s, "cards", index)} for s in series_slugs
            ]
        # auto-inyeccion: id negativo si no hay id (CREATE de dashcard)
        if "id" not in dc:
            while next_neg_id in used_neg_ids:
                next_neg_id -= 1
            dc["id"] = next_neg_id
            used_neg_ids.add(next_neg_id)
            next_neg_id -= 1
        # auto-inyeccion: viz_settings y parameter_mappings vacios si faltan
        dc.setdefault("visualization_settings", {})
        dc.setdefault("parameter_mappings", [])
        new_dashcards.append(dc)
    payload["dashcards"] = new_dashcards

    return payload


def build_database_payload(doc: dict, index: dict, env: dict) -> dict:
    """Construye payload de database. Resuelve passwords desde env vars.

    Si details.password es ${VAR}, lo sustituye por env[VAR]. Si no esta,
    deja el placeholder (push fallara con error claro).
    """
    payload = copy.deepcopy(doc.get("payload", {}) or {})
    details = payload.get("details", {}) or {}
    pwd = details.get("password")
    if isinstance(pwd, str) and pwd.startswith("${") and pwd.endswith("}"):
        var_name = pwd[2:-1]
        if var_name in env:
            details["password"] = env[var_name]
        # si no esta, queda el placeholder y push fallara
    payload["details"] = details
    return payload


def build_collection_payload(doc: dict, index: dict) -> dict:
    refs = doc.get("_refs", {}) or {}
    payload = copy.deepcopy(doc.get("payload", {}) or {})
    if "parent" in refs:
        parent_slug = refs["parent"]
        payload["parent_id"] = _resolve_slug(parent_slug, "collections", index)
    return payload


# ---------------------------------------------------------------- Dispatch


_BUILDERS = {
    "card": build_card_payload,
    "dashboard": build_dashboard_payload,
    "database": build_database_payload,
    "collection": build_collection_payload,
}


def build_payload(kind: str, doc: dict, index: dict, env: dict | None = None) -> dict:
    """Punto de entrada: dispatch por kind."""
    if kind not in _BUILDERS:
        raise ValueError(f"kind '{kind}' desconocido. Validos: {sorted(_BUILDERS)}")
    if kind == "database":
        return _BUILDERS[kind](doc, index, env or {})
    return _BUILDERS[kind](doc, index)


def known_card_ids(index: dict) -> set[int]:
    """Set de ids de cards conocidas (para validacion de dashcards)."""
    return set(index.get("cards", {}).values())


# ---------------------------------------------------------------- Lookup paths


def item_path(project_dir: Path, kind: str, slug: str) -> Path:
    """Path al YAML de un item: cards/foo.yaml, dashboards/bar.yaml, etc."""
    return project_dir / (kind + "s") / f"{slug}.yaml"