use fake::faker;
use fake::{Fake, Faker};
use rand::Rng;
use serde_derive::{Deserialize, Serialize};
use std::ops::Add;
use uuid;

/// An Enum that represents all of the possible random data generation types.
/// Where the type is a struct it should be written in a specification as a nested map type,
/// where the outer map contains a single property correlating to the struct variant
/// with value should be a map containing the struct values.
///
/// # Examples
///
/// ## Basic Model (JSON)
///
/// To model a company identification card that contains basic employee information using simple
/// types:
///
/// ```json
/// {
///     "information_card": {
///         "name": "FullName",
///         "contact_email": "Email",
///         "contact_number": "PhoneNumber",
///         "address": "FullAddress"
///     }
/// }
/// ```
///
/// ## Model With Struct Types (JSON)
///
/// To use complex data types that take arguments, you need to write the property values as
/// nested map types. This example models an Under-25 Travelcard for a train company, where
/// the age of the person needs to be between 18 and 25. The `NumberBetween` type takes two
/// arguments:
///
/// ```json
/// {
///     "travelcard": {
///         "name": "FullName",
///         "address": "FullAddress",
///         "age": {
///             "NumberBetween": {
///                 "min": 18,
///                 "max": 25
///             }
///         }
///     }
/// }
/// ```
#[derive(Clone, Debug, Serialize, Deserialize)]
pub enum RandomData {
	/// Generates a latin first name
	FirstName,
	/// Generates a latin surname
	LastName,
	/// Generates a combination of a `FirstName` and `LastName`, combined with a space between them
	FullName,
	/// Generates a safe email address
	Email,
	/// Generates an integer with the given number of digits.
	///
	/// ## Examples
	///
	/// `Number: { "digits": 3 }` will generate a number between 100 and 999, inclusive
	Number {
		/// The number of digits the generated number should have, to get a number with an appropriate
		/// order of magnitude
		digits: usize,
	},
	/// Generate a random number between the minimum and maximum boundaries
	///
	/// ## Examples
	///
	/// `NumberBetween: { "min": 23, "max": 50 }` will generate a number between 23 and 49, inclusive
	NumberBetween {
		/// The minimum boundary for the generated number. This boundary is inclusive
		min: usize,
		/// The maximum boundary for the generated number. This boundary is exclusive
		max: usize,
	},
	/// Generate a number of paragraphs containing raw lorem ipsum text (No formatting)
	Paragraphs {
		/// The number of paragraphs to generate. Defaults to 1
		amount: Option<usize>,
	},
	/// Generate a single paragraph of lorem ipsum text. This is a convenience for specifying
	/// `Paragraphs` as a simple type without options
	Paragraph,
	/// Generate a number of sentences containing raw lorem ipsum text (No formatting)
	Sentences {
		/// The number of sentences to generate. Defaults to 1
		amount: Option<usize>,
	},
	/// Generate a single sentence of lorem ipsum text. This is a convenience for specifying
	/// `Sentences` as a simple type without options
	Sentence,
	/// Generates the name of a local company - usually an amalgamation of name-parts
	Company,
	/// Generates the name of a city
	City,
	/// Generates a sensible street address (including house number and street name components)
	StreetAddress,
	/// Generates a valid latitude component
	Latitude,
	/// Generates a valid longitude component
	Longitude,
	/// Generates a coordinate pair, formatted as a JSON array of (Latitude, Longitude)
	LatLong,
	/// Generates a coordinate pair, formatted as a JSON array of (Longitude, Latitude)
	LongLat,
	/// Generates a GeoJson point object using the WKT formatting for postgis recognition and insertion
	GeoPoint,
	/// Generates a valid postcode
	Postcode,
	/// Generates an address with `StreetAddress`, `City` and `PostCode` components, separated by commas
	FullAddress,
	/// Generates a valid V4 UUID, generally useful for object IDs
	UUID4,
	/// Generates a valid phone number
	PhoneNumber,
	/// Generates a URL to a random picture with the given dimensions and optional greyscale mode.
	/// Where one of the size values is absent, the image will be a square as dictated by the
	/// other value that is present. Where both are absent, the image will be a 200x200 pixel square.
	LoremPicsum {
		width: Option<usize>,
		height: Option<usize>,
		grayscale: Option<bool>,
	},
	NullValue,
	String {
		content: String,
	},
	Reference {
		model: String,
		field: String,
	},
}

impl RandomData {
	/// Consumes the `RandomData` instance and turns it into a random piece of data, corresponding to
	/// its type
	pub fn into_data(self) -> String {
		generate_fake_data(self)
	}
}

impl std::string::ToString for RandomData {
	fn to_string(&self) -> String {
		self.clone().into_data()
	}
}

/// Create a number of a certain length. The value is returned as a string for display,
/// and can therefore represent a number of arbitrary length at the expense of higher memory
/// consumption.
///
/// The first digit will be in the range 1-9, whilst the following digits will be between 0-9.
///
/// # Examples
///
/// ```rust
/// let three_digit_number = number_with_length(3);
/// println!("{}", three_digit_number);
/// ```
fn number_with_length(length: usize) -> String {
	let mut random = rand::thread_rng();
	let mut buffer = String::with_capacity(length);
	buffer = buffer + &format!("{}", random.gen_range(1, 10));

	for _ in 0..length - 1 {
		buffer = buffer + &format!("{}", random.gen_range(0, 10));
	}

	buffer
}

#[test]
fn generate_number_format_of_correct_length() {
	assert_eq!(number_with_length(1).len(), 1);
	assert_eq!(number_with_length(2).len(), 2);
	assert_eq!(number_with_length(10).len(), 10);
	assert_eq!(number_with_length(1000).len(), 1000);
}

/// Use a `RandomData` definition to generate a random string of data
///
/// # Examples
///
/// ```rust
/// use mockery::datatypes::{RandomData, generate_fake_data};
/// println!(
///     "Hello {}, your new email address is {}",
///     generate_fake_data(RandomData::FullName),
///     generate_fake_data(RandomData::Email)
/// )
/// ```
pub fn generate_fake_data(spec: RandomData) -> String {
	match spec {
		RandomData::FirstName => format!("{}", faker::name::en::FirstName().fake::<String>()),
		RandomData::LastName => format!("{}", faker::name::en::LastName().fake::<String>()),
		RandomData::FullName => format!("{}", faker::name::en::Name().fake::<String>()),
		RandomData::Email => format!("{}", faker::internet::en::SafeEmail().fake::<String>()),
		RandomData::Number { digits } => format!("{}", number_with_length(digits)),
		RandomData::NumberBetween { min, max } => {
			format!("{}", rand::thread_rng().gen_range(min, max))
		}
		RandomData::Paragraph => faker::lorem::en::Paragraph(1..2).fake::<String>(),
		RandomData::Paragraphs { amount } => {
			let val = amount.unwrap_or(1usize);
			format!(
				"{}",
				faker::lorem::en::Paragraph(val..val + 1).fake::<String>()
			)
		}
		RandomData::Sentence => faker::lorem::en::Sentence(1..2).fake::<String>(),
		RandomData::Sentences { amount } => {
			let val = amount.unwrap_or(1usize);
			format!(
				"{}",
				faker::lorem::en::Sentence(val..val + 1).fake::<String>()
			)
		}
		RandomData::Company => format!("{}", faker::company::en::CompanyName().fake::<String>()),
		RandomData::City => format!("{}", faker::address::en::CityName().fake::<String>()),
		RandomData::StreetAddress => {
			format!("{}", faker::address::en::StreetName().fake::<String>())
		}
		RandomData::Latitude => format!("{}", faker::address::en::Latitude().fake::<String>()),
		RandomData::Longitude => format!("{}", faker::address::en::Longitude().fake::<String>()),
		RandomData::LatLong => format!(
			r#"[{}, {}]"#,
			faker::address::en::Latitude().fake::<String>(),
			faker::address::en::Longitude().fake::<String>()
		),
		RandomData::LongLat => format!(
			r#"[{}, {}]"#,
			faker::address::en::Longitude().fake::<String>(),
			faker::address::en::Latitude().fake::<String>()
		),
		RandomData::GeoPoint => format!(
			r#"POINT({} {})"#,
			faker::address::en::Longitude().fake::<String>(),
			faker::address::en::Latitude().fake::<String>()
		),
		RandomData::Postcode => format!("{}", faker::address::en::PostCode().fake::<String>()),
		RandomData::FullAddress => format!(
			"{}, {}, {}",
			faker::address::en::StreetName().fake::<String>(),
			faker::address::en::CityName().fake::<String>(),
			faker::address::en::PostCode().fake::<String>()
		),
		RandomData::UUID4 => format!("{}", uuid::Uuid::new_v4()),
		RandomData::PhoneNumber => format!(
			"{}",
			faker::phone_number::en::PhoneNumber().fake::<String>()
		),
		RandomData::LoremPicsum {
			width,
			height,
			grayscale,
		} => format!(
			"https://picusm.photos/{}{}/{}",
			if grayscale.unwrap_or(false) { "g/" } else { "" },
			width.unwrap_or(200),
			height.unwrap_or(200)
		),
		RandomData::NullValue => format!("null"),
		RandomData::String { content } => content.clone(),
		RandomData::Reference { .. } => format!("null"),
	}
}