use std::ops::Add;
use std::time::{Duration, SystemTime};

use crate::base::{Base, Body, PrivateOptions};
use crate::options::Options;
use crate::page::{Page, PageBuilder, PageInfo};
use crate::service::Service;
use crate::types::*;

/// Publisher trait allows services to generate primary, data, and secondary pages
/// as well as to encode (and sign and optionally encrypt) generated pages
pub trait Publisher {
    /// Generates a primary page to publish for the given service and encodes it into the provided buffer
    fn publish_primary<T: AsRef<[u8]> + AsMut<[u8]>>(
        &mut self,
        buff: T,
    ) -> Result<(usize, Page), Error>;

    /// Create a data object for publishing with the provided options and encodes it into the provided buffer
    fn publish_data<T: AsRef<[u8]> + AsMut<[u8]>>(
        &mut self,
        options: DataOptions,
        buff: T,
    ) -> Result<(usize, Page), Error>;

    /// Create a secondary page for publishing with the provided options and encodes it into the provided buffer
    fn publish_secondary<T: AsRef<[u8]> + AsMut<[u8]>>(
        &mut self,
        options: SecondaryOptions,
        buff: T,
    ) -> Result<(usize, Page), Error>;
}

#[derive(Clone, Builder)]
pub struct SecondaryOptions {
    /// ID of primary service
    id: Id,

    /// Application ID of primary service
    #[builder(default = "0")]
    application_id: u16,

    /// Page object kind
    #[builder(default = "Kind(0)")]
    page_kind: Kind,

    /// Page version
    /// This is monotonically increased for any successive publishing of the same page
    #[builder(default = "0")]
    version: u16,

    /// Page body
    #[builder(default = "Body::None")]
    body: Body,

    /// Page expiry time
    #[builder(default = "Some(SystemTime::now().add(Duration::from_secs(24 * 60 * 60)))")]
    expiry: Option<SystemTime>,

    /// Public options attached to the page
    #[builder(default = "vec![]")]
    public_options: Vec<Options>,

    /// Private options attached to the page
    #[builder(default = "PrivateOptions::None")]
    private_options: PrivateOptions,
}

#[derive(Clone, Builder)]
pub struct DataOptions {
    /// Data object kind
    #[builder(default = "DataKind::Generic.into()")]
    data_kind: Kind,

    /// Data object body
    #[builder(default = "Body::None")]
    body: Body,

    /// Data expiry time
    #[builder(default = "None")]
    expiry: Option<SystemTime>,

    /// Public options attached to the data object
    #[builder(default = "vec![]")]
    public_options: Vec<Options>,

    /// Private options attached to the data object
    #[builder(default = "PrivateOptions::None")]
    private_options: PrivateOptions,
}

impl Publisher for Service {
    /// Publish generates a page to publishing for the given service.
    fn publish_primary<T: AsRef<[u8]> + AsMut<[u8]>>(
        &mut self,
        buff: T,
    ) -> Result<(usize, Page), Error> {
        let mut flags = Flags::default();
        if self.encrypted {
            flags |= Flags::ENCRYPTED;
        }

        // Build page
        let mut p = Page::new(
            self.id.clone(),
            self.application_id,
            self.kind.into(),
            flags,
            self.version,
            PageInfo::primary(self.public_key.clone()),
            self.body.clone(),
            SystemTime::now(),
            Some(SystemTime::now().add(Duration::from_secs(24 * 60 * 60))),
        );

        self.encode(&mut p, buff).map(|n| (n, p))
    }

    /// Secondary generates a secondary page using this service to be attached to the provided service ID
    fn publish_secondary<T: AsRef<[u8]> + AsMut<[u8]>>(
        &mut self,
        options: SecondaryOptions,
        buff: T,
    ) -> Result<(usize, Page), Error> {
        let mut flags = Flags::SECONDARY;
        if self.encrypted {
            flags |= Flags::ENCRYPTED;
        }

        assert!(options.page_kind.is_page());

        //let mut p = Page::new(options.id.clone(), options.application_id, options.page_kind, flags, options.version, PageInfo::secondary(self.id.clone()), options.body, SystemTime::now(), options.expiry);

        let mut b = PageBuilder::default();
        b.id(options.id.clone())
            .application_id(options.application_id)
            .kind(options.page_kind)
            .flags(flags)
            .version(options.version)
            .info(PageInfo::secondary(self.id.clone()))
            .body(options.body)
            .public_options(options.public_options)
            .private_options(options.private_options)
            .issued(SystemTime::now().into())
            .expiry(options.expiry.map(|v| v.into()));

        let mut p = b.build().unwrap();

        self.encode(&mut p, buff).map(|n| (n, p))
    }

    fn publish_data<T: AsRef<[u8]> + AsMut<[u8]>>(
        &mut self,
        options: DataOptions,
        buff: T,
    ) -> Result<(usize, Page), Error> {
        let mut flags = Flags::default();
        if self.encrypted {
            flags |= Flags::ENCRYPTED;
        }

        assert!(options.data_kind.is_data());

        self.data_index += 1;

        let mut p = Page::new(
            self.id.clone(),
            self.application_id,
            options.data_kind,
            flags,
            self.data_index,
            PageInfo::Data(()),
            options.body,
            SystemTime::now(),
            options.expiry,
        );

        self.encode(&mut p, buff).map(|n| (n, p))
    }
}

impl Service {
    // Encode a page to the provided buffer, updating the internal signature state
    fn encode<T: AsRef<[u8]> + AsMut<[u8]>>(
        &mut self,
        page: &mut Page,
        buff: T,
    ) -> Result<usize, Error> {
        // Map page to base object
        let mut b = Base::from(&*page);

        // Attach previous signature
        b.parent = self.last_sig.clone();

        // Encode and sign object
        let n = b.encode(self.private_key.as_ref(), self.secret_key.as_ref(), buff)?;

        // Update service last_sig
        self.last_sig = b.signature;

        // Attach page sig
        page.signature = self.last_sig.clone();

        // TODO: should we attach the raw object here..?

        Ok(n)
    }
}