use futures::StreamExt;
use mongod::{
    assert_reference_of,
    derive::{Model, Referencable},
    reference_of, Model, Referencable, Reference, Sort, Validate,
};
use mongodb::bson::doc;
use serde::{Deserialize, Serialize};
use serde_json::json;

use crate::{item::Item, location::Location};

/// A Transaction of an Item Variant
#[derive(Debug, Clone, Serialize, Deserialize, Model, Referencable)]
pub struct Transaction {
    /// UUID
    pub _id: String,
    /// Associated Item
    pub item: String,
    /// Associated Variant
    pub variant: String,
    /// Price of obtaining the Item
    pub price: Price,
    /// Origin of the Item
    pub origin: Option<String>,
    /// The location of the Item
    pub location: Option<Reference>,
    /// Info on consumption of the Item
    pub consumed: Option<Consumed>,
    /// Timestamp of the Transaction
    pub timestamp: i64,
}

impl Validate for Transaction {
    async fn validate(&self) -> Result<(), String> {
        if let Some(location) = &self.location {
            assert_reference_of!(location, Location);
        }

        Ok(())
    }
}

/// Information about consumed Items
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub struct Consumed {
    /// Destination of the Item or who consumed it
    pub destination: String,
    /// Price the Item was exported or consumed at
    pub price: Price,
    /// Timestamp of Consumption
    pub timestamp: i64,
}

impl Transaction {
    pub async fn new(
        item: &str,
        variant: &str,
        price: Price,
        origin: Option<&str>,
        location: Option<&str>,
    ) -> Self {
        Self {
            _id: uuid::Uuid::new_v4().to_string(),
            item: item.to_string(),
            variant: variant.to_string(),
            price,
            consumed: None,
            origin: origin.map(std::string::ToString::to_string),
            location: if let Some(location) = location {
                reference_of!(Location, location)
            } else {
                None
            },
            timestamp: chrono::Utc::now().timestamp(),
        }
    }

    /// Consumes the Item with `price` and `destination`
    pub async fn consume(self, price: Price, destination: &str) -> Self {
        self.change()
            .consumed(Some(Consumed {
                destination: destination.to_string(),
                price,
                timestamp: chrono::Utc::now().timestamp(),
            }))
            .update()
            .await
            .unwrap()
    }

    pub async fn is_expired(&self) -> bool {
        let current_time = chrono::Utc::now().timestamp();

        if let Some(expiry) = Item::get(&self.item)
            .await
            .unwrap()
            .variant(&self.variant)
            .unwrap()
            .expiry
        {
            let date_added = self.timestamp;

            let expiration_ts = expiry * 24 * 60 * 60;

            return (date_added + expiration_ts) < current_time;
        }

        false
    }

    pub async fn in_location(l: &str) -> Vec<Self> {
        Self::find(doc! { "location": l}, None, None).await.unwrap()
    }

    pub async fn in_location_recursive(l: &str) -> Vec<Self> {
        let locations = Location::find(doc! { "parent": l}, None, None)
            .await
            .unwrap();
        let mut transactions = Self::find(doc! { "location": l}, None, None).await.unwrap();

        for loc in locations {
            transactions.extend(
                Self::find(doc! { "location": loc.id() }, None, None)
                    .await
                    .unwrap(),
            );
        }

        transactions
    }

    /// Get all Transactions which are not consumed and are expired
    pub async fn active_expired() -> Vec<Self> {
        let items = Self::find(
            doc! {
                "consumed": { "$not": { "$type": "object" } }
            },
            None,
            Some(doc! { "timestamp": Sort::Descending }),
        )
        .await
        .unwrap();

        let expired_items: Vec<_> = futures::stream::iter(items)
            .filter_map(|item| async move {
                if item.is_expired().await {
                    Some(item)
                } else {
                    None
                }
            })
            .collect()
            .await;

        expired_items
    }
}

impl mongod::ToAPI for Transaction {
    async fn api(&self) -> serde_json::Value {
        json!({
            "uuid": self._id,
            "item": self.item,
            "variant": self.variant,
            "price": self.price,
            "origin": self.origin,
            "timestamp": self.timestamp,
            "consumed": self.consumed,
            "expired": self.is_expired().await
        })
    }
}

/// Economic Price
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub struct Price {
    /// Value of the currency
    pub value: f64,
    /// Kind of currency
    pub currency: String,
}

impl Price {
    pub fn new(value: f64, currency: &str) -> Self {
        Self {
            value,
            currency: currency.to_string(),
        }
    }

    fn parse(price: &str) -> Option<Self> {
        let (value, currency) = price.split_once(' ')?;

        Some(Self {
            value: value.parse().ok()?,
            currency: currency.to_string(),
        })
    }
}

impl TryFrom<String> for Price {
    type Error = ();

    fn try_from(value: String) -> Result<Self, Self::Error> {
        Self::parse(&value).ok_or(())
    }
}