import type { Hex } from "viem"
import type { ArkivClient } from "../../clients/baseClient"
import { NoEntityFoundError } from "../../errors"
import { type FullEntity, type FullRow, projectSelection, toRow } from "../../query/selection"
import { isSchema, key, type Schema, SchemaDefinitionError } from "../../schema"
import { entityFromRpcResult } from "../../utils/entities"

/**
 * Reads one entity by key, with every field.
 *
 * The same row as `select("*")`: a {@link FullEntity} — every entity field and every attribute as
 * the `$attributes` map — with none of them needing a `?` at the call site.
 *
 * Given a schema, it reads the entity through it instead, as `select("*").from(schema)` would — a
 * {@link FullRow}, every entity field and every column, each column checked against its declared
 * type, and a named schema's tag checked against its name.
 *
 * @throws {InvalidValueError} If the key is not 32 bytes.
 * @throws {NoEntityFoundError} If no live entity has that key — it never existed, or it was
 * deleted or has expired.
 * @throws {SchemaMismatchError} If, given a schema, the entity does not fit it.
 * @throws {SchemaDefinitionError} If the schema given was not built with `defineSchema`.
 */
export async function getEntity(client: ArkivClient, entityKey: Hex): Promise<FullEntity>
export async function getEntity<S extends Schema>(
  client: ArkivClient,
  entityKey: Hex,
  schema: S,
): Promise<FullRow<S>>
export async function getEntity(
  client: ArkivClient,
  entityKey: Hex,
  schema?: Schema,
): Promise<FullEntity | FullRow<Schema>> {
  if (schema !== undefined && !isSchema(schema)) {
    throw new SchemaDefinitionError("getEntity() takes a schema built with defineSchema(...)")
  }
  const projection = projectSelection("*", schema)
  const rpcEntity = await client.request({
    method: "arkiv_getEntity",
    params: [key(entityKey).value],
  })
  if (rpcEntity === null) {
    throw new NoEntityFoundError(entityKey)
  }
  // Every field was selected, so the row carries them all; the cast is the same narrowing
  // `client.select("*")` gets from its own inference.
  return toRow(entityFromRpcResult(rpcEntity), projection) as FullEntity | FullRow<Schema>
}