use crate::{
    fuel_core_graphql_api::{
        api_service::ConsensusProvider,
        database::ReadView,
    },
    query::BalanceQueryData,
    schema::scalars::{
        Address,
        AssetId,
        U64,
    },
};
use anyhow::anyhow;
use async_graphql::{
    connection::{
        Connection,
        EmptyFields,
    },
    Context,
    InputObject,
    Object,
};
use fuel_core_types::services::graphql_api;

pub struct Balance(graphql_api::AddressBalance);

#[Object]
impl Balance {
    async fn owner(&self) -> Address {
        self.0.owner.into()
    }

    async fn amount(&self) -> U64 {
        self.0.amount.into()
    }

    async fn asset_id(&self) -> AssetId {
        self.0.asset_id.into()
    }
}

#[derive(InputObject)]
struct BalanceFilterInput {
    /// Filter coins based on the `owner` field
    owner: Address,
}

#[derive(Default)]
pub struct BalanceQuery;

#[Object]
impl BalanceQuery {
    async fn balance(
        &self,
        ctx: &Context<'_>,
        #[graphql(desc = "address of the owner")] owner: Address,
        #[graphql(desc = "asset_id of the coin")] asset_id: AssetId,
    ) -> async_graphql::Result<Balance> {
        let query: &ReadView = ctx.data_unchecked();
        let base_asset_id = *ctx
            .data_unchecked::<ConsensusProvider>()
            .latest_consensus_params()
            .base_asset_id();
        let balance = query.balance(owner.0, asset_id.0, base_asset_id)?.into();
        Ok(balance)
    }

    // TODO: We can't paginate over `AssetId` because it is not unique.
    //  It should be replaced with `UtxoId`.
    //  This API should be migrated to the indexer for better support and
    //  discontinued within fuel-core.
    async fn balances(
        &self,
        ctx: &Context<'_>,
        filter: BalanceFilterInput,
        first: Option<i32>,
        after: Option<String>,
        last: Option<i32>,
        before: Option<String>,
    ) -> async_graphql::Result<Connection<AssetId, Balance, EmptyFields, EmptyFields>>
    {
        if before.is_some() || after.is_some() {
            return Err(anyhow!("pagination is not yet supported").into())
        }
        let query: &ReadView = ctx.data_unchecked();
        crate::schema::query_pagination(after, before, first, last, |_, direction| {
            let owner = filter.owner.into();
            let base_asset_id = *ctx
                .data_unchecked::<ConsensusProvider>()
                .latest_consensus_params()
                .base_asset_id();
            Ok(query
                .balances(owner, direction, base_asset_id)
                .map(|result| {
                    result.map(|balance| (balance.asset_id.into(), balance.into()))
                }))
        })
        .await
    }
}

impl From<graphql_api::AddressBalance> for Balance {
    fn from(balance: graphql_api::AddressBalance) -> Self {
        Balance(balance)
    }
}