//! Standard for nep141 (Fungible Token) events.
//!
//! These events will be picked up by the NEAR indexer.
//!
//! <https://github.com/near/NEPs/blob/master/specs/Standards/FungibleToken/Event.md>
//!
//! This is an extension of the events format (nep-297):
//! <https://github.com/near/NEPs/blob/master/specs/Standards/EventsFormat.md>
//!
//! The three events in this standard are [`FtMint`], [`FtTransfer`], and [`FtBurn`].
//!
//! These events can be logged by calling `.emit()` on them if a single event, or calling
//! [`FtMint::emit_many`], [`FtTransfer::emit_many`],
//! or [`FtBurn::emit_many`] respectively.

use crate::event::NearEvent;
use near_sdk::json_types::U128;
use near_sdk::serde::Serialize;
use near_sdk::AccountIdRef;

/// Data to log for an FT mint event. To log this event, call [`.emit()`](FtMint::emit).
#[must_use]
#[derive(Serialize, Debug, Clone)]
#[serde(crate = "near_sdk::serde")]
pub struct FtMint<'a> {
    pub owner_id: &'a AccountIdRef,
    pub amount: U128,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub memo: Option<&'a str>,
}

impl FtMint<'_> {
    /// Logs the event to the host. This is required to ensure that the event is triggered
    /// and to consume the event.
    pub fn emit(self) {
        Self::emit_many(&[self])
    }

    /// Emits an FT mint event, through [`env::log_str`](near_sdk::env::log_str),
    /// where each [`FtMint`] represents the data of each mint.
    pub fn emit_many(data: &[FtMint<'_>]) {
        new_141_v1(Nep141EventKind::FtMint(data)).emit()
    }
}

/// Data to log for an FT transfer event. To log this event,
/// call [`.emit()`](FtTransfer::emit).
#[must_use]
#[derive(Serialize, Debug, Clone)]
#[serde(crate = "near_sdk::serde")]
pub struct FtTransfer<'a> {
    pub old_owner_id: &'a AccountIdRef,
    pub new_owner_id: &'a AccountIdRef,
    pub amount: U128,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub memo: Option<&'a str>,
}

impl FtTransfer<'_> {
    /// Logs the event to the host. This is required to ensure that the event is triggered
    /// and to consume the event.
    pub fn emit(self) {
        Self::emit_many(&[self])
    }

    /// Emits an FT transfer event, through [`env::log_str`](near_sdk::env::log_str),
    /// where each [`FtTransfer`] represents the data of each transfer.
    pub fn emit_many(data: &[FtTransfer<'_>]) {
        new_141_v1(Nep141EventKind::FtTransfer(data)).emit()
    }
}

/// Data to log for an FT burn event. To log this event, call [`.emit()`](FtBurn::emit).
#[must_use]
#[derive(Serialize, Debug, Clone)]
#[serde(crate = "near_sdk::serde")]
pub struct FtBurn<'a> {
    pub owner_id: &'a AccountIdRef,
    pub amount: U128,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub memo: Option<&'a str>,
}

impl FtBurn<'_> {
    /// Logs the event to the host. This is required to ensure that the event is triggered
    /// and to consume the event.
    pub fn emit(self) {
        Self::emit_many(&[self])
    }

    /// Emits an FT burn event, through [`env::log_str`](near_sdk::env::log_str),
    /// where each [`FtBurn`] represents the data of each burn.
    pub fn emit_many<'a>(data: &'a [FtBurn<'a>]) {
        new_141_v1(Nep141EventKind::FtBurn(data)).emit()
    }
}

#[derive(Serialize, Debug)]
#[serde(crate = "near_sdk::serde")]
pub(crate) struct Nep141Event<'a> {
    version: &'static str,
    #[serde(flatten)]
    event_kind: Nep141EventKind<'a>,
}

#[derive(Serialize, Debug)]
#[serde(crate = "near_sdk::serde")]
#[serde(tag = "event", content = "data")]
#[serde(rename_all = "snake_case")]
#[allow(clippy::enum_variant_names)]
enum Nep141EventKind<'a> {
    FtMint(&'a [FtMint<'a>]),
    FtTransfer(&'a [FtTransfer<'a>]),
    FtBurn(&'a [FtBurn<'a>]),
}

fn new_141<'a>(version: &'static str, event_kind: Nep141EventKind<'a>) -> NearEvent<'a> {
    NearEvent::Nep141(Nep141Event { version, event_kind })
}

fn new_141_v1(event_kind: Nep141EventKind) -> NearEvent {
    new_141("1.0.0", event_kind)
}

#[cfg(test)]
mod tests {
    use super::*;
    use near_sdk::{test_utils, AccountIdRef};

    #[test]
    fn ft_mint() {
        let owner_id = AccountIdRef::new_or_panic("bob");
        let amount = U128(100);
        FtMint { owner_id, amount, memo: None }.emit();
        assert_eq!(
            test_utils::get_logs()[0],
            r#"EVENT_JSON:{"standard":"nep141","version":"1.0.0","event":"ft_mint","data":[{"owner_id":"bob","amount":"100"}]}"#
        );
    }

    #[test]
    fn ft_mints() {
        let owner_id = AccountIdRef::new_or_panic("bob");
        let amount = U128(100);
        let mint_log = FtMint { owner_id, amount, memo: None };
        FtMint::emit_many(&[
            mint_log,
            FtMint {
                owner_id: AccountIdRef::new_or_panic("alice"),
                amount: U128(200),
                memo: Some("has memo"),
            },
        ]);
        assert_eq!(
            test_utils::get_logs()[0],
            r#"EVENT_JSON:{"standard":"nep141","version":"1.0.0","event":"ft_mint","data":[{"owner_id":"bob","amount":"100"},{"owner_id":"alice","amount":"200","memo":"has memo"}]}"#
        );
    }

    #[test]
    fn ft_burn() {
        let owner_id = AccountIdRef::new_or_panic("bob");
        let amount = U128(100);
        FtBurn { owner_id, amount, memo: None }.emit();
        assert_eq!(
            test_utils::get_logs()[0],
            r#"EVENT_JSON:{"standard":"nep141","version":"1.0.0","event":"ft_burn","data":[{"owner_id":"bob","amount":"100"}]}"#
        );
    }

    #[test]
    fn ft_burns() {
        let owner_id = AccountIdRef::new_or_panic("bob");
        let amount = U128(100);
        FtBurn::emit_many(&[
            FtBurn {
                owner_id: AccountIdRef::new_or_panic("alice"),
                amount: U128(200),
                memo: Some("has memo"),
            },
            FtBurn { owner_id, amount, memo: None },
        ]);
        assert_eq!(
            test_utils::get_logs()[0],
            r#"EVENT_JSON:{"standard":"nep141","version":"1.0.0","event":"ft_burn","data":[{"owner_id":"alice","amount":"200","memo":"has memo"},{"owner_id":"bob","amount":"100"}]}"#
        );
    }

    #[test]
    fn ft_transfer() {
        let old_owner_id = AccountIdRef::new_or_panic("bob");
        let new_owner_id = AccountIdRef::new_or_panic("alice");
        let amount = U128(100);
        FtTransfer { old_owner_id, new_owner_id, amount, memo: None }.emit();
        assert_eq!(
            test_utils::get_logs()[0],
            r#"EVENT_JSON:{"standard":"nep141","version":"1.0.0","event":"ft_transfer","data":[{"old_owner_id":"bob","new_owner_id":"alice","amount":"100"}]}"#
        );
    }

    #[test]
    fn ft_transfers() {
        let old_owner_id = AccountIdRef::new_or_panic("bob");
        let new_owner_id = AccountIdRef::new_or_panic("alice");
        let amount = U128(100);
        FtTransfer::emit_many(&[
            FtTransfer {
                old_owner_id: AccountIdRef::new_or_panic("alice"),
                new_owner_id: AccountIdRef::new_or_panic("bob"),
                amount: U128(200),
                memo: Some("has memo"),
            },
            FtTransfer { old_owner_id, new_owner_id, amount, memo: None },
        ]);
        assert_eq!(
            test_utils::get_logs()[0],
            r#"EVENT_JSON:{"standard":"nep141","version":"1.0.0","event":"ft_transfer","data":[{"old_owner_id":"alice","new_owner_id":"bob","amount":"200","memo":"has memo"},{"old_owner_id":"bob","new_owner_id":"alice","amount":"100"}]}"#
        );
    }
}