exjoi

defmodule ExJoi do
  @moduledoc """

  ExJoi - A Joi-inspired validation library for Elixir.



  Provides declarative, schema-based data validation with a clean DSL.



  ## Basic Usage



      schema = ExJoi.schema(%{

        name: ExJoi.string(required: true),

        age: ExJoi.number()

      })



      ExJoi.validate(%{name: "John", age: 30}, schema)

      # => {:ok, %{name: "John", age: 30}}



      ExJoi.validate(%{age: 30}, schema)

      # => {:error, %{name: ["is required"]}}

  """

  alias ExJoi.{Rule, Schema, Validator}

  @default_truthy [true, "true", "True", "TRUE", "1", 1, "yes", "Yes", "YES", "on", "On", "ON"]
  @default_falsy [false, "false", "False", "FALSE", "0", 0, "no", "No", "NO", "off", "Off", "OFF"]

  @doc """

  Creates a validation schema from a map of field rules.



  ## Examples



      schema = ExJoi.schema(%{

        name: ExJoi.string(required: true),

        age: ExJoi.number()

      })

  """
  def schema(fields) when is_map(fields) do
    %Schema{fields: fields}
  end

  @doc """

  Creates a string validator rule.



  ## Options



    * `:required` - Ensures the value is present.

    * `:min` - Minimum string length.

    * `:max` - Maximum string length.

    * `:pattern` - A `Regex` the string must match.

    * `:email` - When true, applies a basic email format check.



  ## Examples



      ExJoi.string()

      ExJoi.string(required: true, min: 3, max: 50)

      ExJoi.string(pattern: ~r/^[A-Z]+$/)

      ExJoi.string(email: true)

  """
  def string(opts \\ []) do
    %Rule{
      type: :string,
      required: Keyword.get(opts, :required, false),
      min: Keyword.get(opts, :min),
      max: Keyword.get(opts, :max),
      pattern: Keyword.get(opts, :pattern),
      email: Keyword.get(opts, :email, false)
    }
  end

  @doc """

  Creates a number validator rule.



  ## Options



    * `:required` - Ensures the value is present.

    * `:min` / `:max` - Numeric bounds (inclusive).

    * `:integer` - When true, only integers are accepted.



  ## Examples



      ExJoi.number()

      ExJoi.number(required: true, min: 18, max: 65)

      ExJoi.number(integer: true)

  """
  def number(opts \\ []) do
    %Rule{
      type: :number,
      required: Keyword.get(opts, :required, false),
      min: Keyword.get(opts, :min),
      max: Keyword.get(opts, :max),
      integer: Keyword.get(opts, :integer, false)
    }
  end

  @doc """

  Creates a boolean validator rule.



  ## Options



    * `:required` - Ensures the value is present.

    * `:truthy` / `:falsy` - Lists of values that should coerce to `true`/`false`.



  The default truthy values are `#{inspect(@default_truthy)}` and falsy values are

  `#{inspect(@default_falsy)}`.



  ## Examples



      ExJoi.boolean()

      ExJoi.boolean(required: true)

      ExJoi.boolean(truthy: ["Y"], falsy: ["N"])

  """
  def boolean(opts \\ []) do
    %Rule{
      type: :boolean,
      required: Keyword.get(opts, :required, false),
      truthy: Keyword.get(opts, :truthy, @default_truthy),
      falsy: Keyword.get(opts, :falsy, @default_falsy)
    }
  end

  @doc """

  Validates data against a schema.



  Returns `{:ok, validated_data}` if validation passes, or `{:error, errors}` if it fails.



  ## Examples



      schema = ExJoi.schema(%{name: ExJoi.string(required: true)})

      ExJoi.validate(%{name: "John"}, schema)

      # => {:ok, %{name: "John"}}



      ExJoi.validate(%{}, schema)

      # => {:error, %{name: ["is required"]}}

  """
  def validate(data, %Schema{} = schema) do
    Validator.validate(data, schema)
  end
end