defmodule CloudKit do
  @moduledoc """
  Elixir client for the [Apple CloudKit API](https://developer.apple.com/documentation/cloudkit/).

  The public surface is intentionally small:

      CloudKit.query_records(%{recordType: "Items"})
      CloudKit.fetch_record("record_name")
      CloudKit.create_record(%{recordType: "Items", fields: %{...}})
      CloudKit.update_record("record_name", %{fields: %{...}})
      CloudKit.delete_record("record_name")
      CloudKit.upload_asset("file_path", "record_type", "field_name")
      CloudKit.token()

  ## Configuration

      config :cloud_kit,
        container_id: System.get_env("CLOUDKIT_CONTAINER_ID"),
        environment: "development", # or "production"
        server_key_id: System.get_env("CLOUDKIT_SERVER_KEY_ID"),
        private_key: System.get_env("CLOUDKIT_PRIVATE_KEY"),
        base_url: "https://api.apple-cloudkit.com"

  Every function also accepts per-call `opts` that override the application config.
  """

  alias CloudKit.{Asset, Client, ServerKey}

  @type opts :: keyword()
  @type response :: {:ok, map()} | {:error, term()}

  @doc "Return a cached-per-call CloudKit **access token** (after the JWT → token exchange)."
  @spec token(opts) :: {:ok, String.t()} | {:error, term()}
  def token(opts \\ []), do: ServerKey.access_token(opts)

  @doc """
  Query records from the CloudKit database.

  ## Parameters

    - `query`: Map containing:
      - `recordType` - The record type to query
      - `filterBy` - Optional filter specification
      - `sortBy` - Optional sort specification
      - `limit` - Maximum records to return (default 200)
      - `desiredKeys` - Optional list of field names to return
    - `opts`:
      - `:zone_id` - Zone ID for record (defaults to default zone)

  ## Examples

      CloudKit.query_records(%{
        recordType: "Items",
        filterBy: [%{fieldName: "name", comparator: "EQUALS", fieldValue: %{value: "Test"}}],
        limit: 50
      })
  """
  @spec query_records(map(), opts) :: {:ok, map()} | {:error, term()}
  def query_records(query, opts \\ []) when is_map(query) do
    Client.post("/public/records/query", %{query: query}, opts)
  end

  @doc """
  Fetch a single record by record name.

  ## Parameters

    - `record_name`: The unique record name
    - `opts`:
      - `:record_type` - Optional record type
      - `:zone_id` - Zone ID for record
      - `:desired_keys` - List of field names to return
  """
  @spec fetch_record(String.t(), opts) :: response
  def fetch_record(record_name, opts \\ []) when is_binary(record_name) do
    body = %{
      records: [%{recordName: record_name}]
    }

    body =
      if record_type = Keyword.get(opts, :record_type) do
        put_in(body, [:records, Access.at(0), :recordType], record_type)
      else
        body
      end

    Client.post("/public/records/lookup", body, opts)
  end

  @doc """
  Create a new record.

  ## Parameters

    - `record`: Map containing:
      - `recordType` - The record type
      - `recordName` - Optional unique record name (generated if not provided)
      - `fields` - Map of field name to value
    - `opts`:
      - `:zone_id` - Zone ID for record

  ## Examples

      CloudKit.create_record(%{
        recordType: "Items",
        fields: %{
          name: %{value: "New Item"},
          price: %{value: 99.99, type: "DOUBLE"}
        }
      })
  """
  @spec create_record(map(), opts) :: response
  def create_record(record, opts \\ []) when is_map(record) do
    Client.post(
      "/public/records/modify",
      %{operations: [%{action: "CREATE", record: record}]},
      opts
    )
  end

  @doc """
  Update an existing record.

  ## Parameters

    - `record_name`: The unique record name
    - `updates`: Map of fields to update
    - `opts`:
      - `:record_type` - The record type
      - `:zone_id` - Zone ID for record

  ## Examples

      CloudKit.update_record("record_123", %{
        fields: %{
          price: %{value: 149.99, type: "DOUBLE"}
        }
      })
  """
  @spec update_record(String.t(), map(), opts) :: response
  def update_record(record_name, updates, opts \\ [])
      when is_binary(record_name) and is_map(updates) do
    record = Map.merge(updates, %{recordName: record_name})

    record =
      if type = Keyword.get(opts, :record_type),
        do: Map.put(record, :recordType, type),
        else: record

    Client.post(
      "/public/records/modify",
      %{operations: [%{action: "UPDATE", record: record}]},
      opts
    )
  end

  @doc """
  Delete a record by record name.

  ## Parameters

    - `record_name`: The unique record name
    - `opts`:
      - `:record_type` - The record type
      - `:zone_id` - Zone ID for record
  """
  @spec delete_record(String.t(), opts) :: :ok | {:error, term()}
  def delete_record(record_name, opts \\ []) when is_binary(record_name) do
    record = %{recordName: record_name}

    record =
      if type = Keyword.get(opts, :record_type),
        do: Map.put(record, :recordType, type),
        else: record

    case Client.post(
           "/public/records/modify",
           %{operations: [%{action: "DELETE", record: record}]},
           opts
         ) do
      {:ok, _} -> :ok
      error -> error
    end
  end

  @doc """
  Upload an asset to CloudKit.

  ## Parameters

    - `file_path`: Path to the file to upload
    - `record_type`: The record type that will use this asset
    - `field_name`: The field name in the record
    - `opts`:
      - `:zone_id` - Zone ID
      - `:record_name` - Optional record name to associate

  ## Examples

      CloudKit.upload_asset("/path/to/image.png", "Items", "image")
  """
  @spec upload_asset(String.t(), String.t(), String.t(), opts) :: response
  def upload_asset(file_path, record_type, field_name, opts \\ [])
      when is_binary(file_path) and is_binary(record_type) and is_binary(field_name) do
    Asset.upload(file_path, record_type, field_name, opts)
  end

  @doc """
  Download an asset from CloudKit.

  ## Parameters

    - `download_url`: The download URL from an asset field
    - `opts`: Download options

  ## Examples

      {:ok, content} = CloudKit.download_asset(record["fields"]["image"]["downloadURL"])
  """
  @spec download_asset(String.t(), opts) :: {:ok, binary()} | {:error, term()}
  def download_asset(download_url, opts \\ []) when is_binary(download_url) do
    Asset.download(download_url, opts)
  end

  @doc """
  List zones in the database.

  ## Parameters

    - `opts`: Optional configuration overrides
  """
  @spec list_zones(opts) :: {:ok, list(map())} | {:error, term()}
  def list_zones(opts \\ []) do
    case Client.post("/public/zones/list", %{}, opts) do
      {:ok, %{"zones" => zones}} -> {:ok, zones}
      {:ok, other} -> {:ok, other}
      error -> error
    end
  end

  @doc """
  Create a custom zone.

  ## Parameters

    - `zone_name`: The zone name
    - `opts`: Optional configuration
  """
  @spec create_zone(String.t(), opts) :: response
  def create_zone(zone_name, opts \\ []) when is_binary(zone_name) do
    Client.post(
      "/public/zones/modify",
      %{
        operations: [%{action: "CREATE", zone: %{zoneID: %{zoneName: zone_name}}}]
      },
      opts
    )
  end

  @doc """
  Delete a zone.

  ## Parameters

    - `zone_name`: The zone name to delete
    - `opts`: Optional configuration
  """
  @spec delete_zone(String.t(), opts) :: :ok | {:error, term()}
  def delete_zone(zone_name, opts \\ []) when is_binary(zone_name) do
    case Client.post(
           "/public/zones/modify",
           %{
             operations: [%{action: "DELETE", zone: %{zoneID: %{zoneName: zone_name}}}]
           },
           opts
         ) do
      {:ok, _} -> :ok
      error -> error
    end
  end

  @doc """
  Create a subscription for change notifications.

  ## Parameters

    - `subscription`: Map containing:
      - `subscriptionType` - Type ("query" or "zone")
      - `recordType` - For query subscriptions, the record type
      - `filters` - Optional filters
      - `notification` - Notification configuration
    - `opts`: Optional configuration

  ## Examples

      CloudKit.create_subscription(%{
        subscriptionType: "query",
        recordType: "Items",
        notification: %{
          alertBody: "A new item was created"
        }
      })
  """
  @spec create_subscription(map(), opts) :: response
  def create_subscription(subscription, opts \\ []) when is_map(subscription) do
    Client.post(
      "/public/subscriptions/modify",
      %{
        operations: [%{action: "CREATE", subscription: subscription}]
      },
      opts
    )
  end

  @doc """
  List active subscriptions.

  ## Parameters

    - `opts`: Optional configuration
  """
  @spec list_subscriptions(opts) :: {:ok, list(map())} | {:error, term()}
  def list_subscriptions(opts \\ []) do
    case Client.post("/public/subscriptions/list", %{}, opts) do
      {:ok, %{"subscriptions" => subs}} -> {:ok, subs}
      {:ok, other} -> {:ok, other}
      error -> error
    end
  end

  @doc """
  Delete a subscription.

  ## Parameters

    - `subscription_id`: The subscription ID to delete
    - `opts`: Optional configuration
  """
  @spec delete_subscription(String.t(), opts) :: :ok | {:error, term()}
  def delete_subscription(subscription_id, opts \\ []) when is_binary(subscription_id) do
    case Client.post(
           "/public/subscriptions/modify",
           %{
             operations: [
               %{action: "DELETE", subscription: %{subscriptionID: subscription_id}}
             ]
           },
           opts
         ) do
      {:ok, _} -> :ok
      error -> error
    end
  end
end