use crate::{DbConnection, QueryResult};
use diesel::prelude::*;

use crate::models::{self, item::Loot};
use crate::schema::claims;

/// A Claim is a request by a single player on an item from group chest.
#[derive(Identifiable, Queryable, Associations, Serialize, Deserialize, Debug)]
#[belongs_to(Loot)]
pub struct Claim {
    /// DB Identifier
    pub id: i32,
    /// ID that references the player making this claim
    pub player_id: i32,
    /// ID that references the loot claimed
    pub loot_id: i32,
    /// WIP: How bad the player wants this item
    pub resolve: i32,
}

impl Claim {
    /// Resolves this claim (player wins the item) and deletes it
    pub fn resolve_claim(&self, conn: &DbConnection) -> QueryResult<()> {
        let loot: Loot = Loot::find(self.loot_id).first(conn)?;
        loot.set_owner(self.player_id, conn)?;
        self.remove(conn)?;
        Ok(())
    }

    fn remove(&self, conn: &DbConnection) -> QueryResult<()> {
        diesel::delete(claims::table.find(self.id)).execute(conn)?;
        Ok(())
    }
}

pub struct Claims<'q>(pub &'q DbConnection);

impl<'q> Claims<'q> {
    /// Get all claims from database
    pub fn all(&self) -> QueryResult<Vec<Claim>> {
        claims::table.load(self.0)
    }

    /// Finds a single claim by association of player and loot ids.
    pub fn find(&self, player_id: i32, loot_id: i32) -> QueryResult<Claim> {
        claims::table
            .filter(claims::dsl::player_id.eq(player_id))
            .filter(claims::dsl::loot_id.eq(loot_id))
            .first(self.0)
    }

    /// Adds a claim in database and returns it.
    ///
    /// Will validate that the claimed item exists and is
    /// actually owned by the group.
    /// Duplicates are also ignored.
    pub fn add(self, player_id: i32, loot_id: i32) -> QueryResult<Claim> {
        // We need to validate that the claimed item exists
        // AND is actually owned by group (id 0)
        let _item = models::item::LootManager(self.0, 0).find(loot_id)?;
        // We also check if claims does not already exists
        if let Ok(_) = self.find(player_id, loot_id) {
            return Err(diesel::result::Error::RollbackTransaction);
        }

        let claim = NewClaim::new(player_id, loot_id);
        diesel::insert_into(claims::table)
            .values(&claim)
            .execute(self.0)?;
        // Return the created claim
        claims::table
            .order(claims::dsl::id.desc())
            .first::<Claim>(self.0)
    }

    /// Removes a claim from database, returning it
    pub fn remove(self, player_id: i32, loot_id: i32) -> QueryResult<Claim> {
        let claim = self.find(player_id, loot_id)?;
        claim.remove(self.0)?;
        Ok(claim)
    }

    pub fn filtered_by_loot(&self, loot_id: i32) -> QueryResult<Vec<Claim>> {
        claims::table
            .filter(claims::dsl::loot_id.eq(loot_id))
            .load(self.0)
    }

    pub(crate) fn grouped_by_item(&self) -> QueryResult<Vec<(models::item::Item, Vec<Claim>)>> {
        let group_loot: Vec<Loot> = Loot::owned_by(0).load(self.0)?;
        let claims = claims::table.load(self.0)?.grouped_by(&group_loot);
        Ok(group_loot
            .into_iter()
            .map(|loot| loot.into_item())
            .zip(claims)
            .collect::<Vec<_>>())
    }
}

#[derive(Insertable, Debug)]
#[table_name = "claims"]
struct NewClaim {
    player_id: i32,
    loot_id: i32,
}

impl NewClaim {
    fn new(player_id: i32, loot_id: i32) -> Self {
        Self { player_id, loot_id }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    type TestResult = Result<(), diesel::result::Error>;

    fn test_connection() -> Result<DbConnection, diesel::result::Error> {
        let conn =
            DbConnection::establish(":memory:").map_err(|_| diesel::result::Error::NotFound)?;
        diesel_migrations::run_pending_migrations(&conn)
            .map_err(|_| diesel::result::Error::NotFound)?;
        let manager = models::player::Players(&conn);
        manager.add("Player1", 0.0)?;
        manager.add("Player2", 0.0)?;
        crate::LootManager(&conn, 0).add_from(&crate::Item {
            id: 0,
            name: "Epee".to_string(),
            base_price: 30,
        })?;
        crate::LootManager(&conn, 1).add_from(&crate::Item {
            id: 0,
            name: "Arc".to_string(),
            base_price: 20,
        })?;
        Ok(conn)
    }

    #[test]
    fn add_claim() -> TestResult {
        let conn = test_connection()?;
        Claims(&conn).add(1, 1)?;
        assert_eq!(Claims(&conn).all()?.len(), 1);
        Ok(())
    }

    #[test]
    fn cannot_duplicate_by_adding() -> TestResult {
        let conn = test_connection()?;
        Claims(&conn).add(1, 1)?;
        let res = Claims(&conn).add(1, 1);
        assert_eq!(res.is_err(), true);
        assert_eq!(Claims(&conn).all()?.len(), 1);
        Ok(())
    }

    #[test]
    fn remove_claim() -> TestResult {
        let conn = test_connection()?;
        let claim = Claims(&conn).add(1, 1)?;
        claim.remove(&conn);
        assert_eq!(Claims(&conn).all()?.len(), 0);
        Ok(())
    }

    #[test]
    fn cannot_only_claim_from_group() -> TestResult {
        let conn = test_connection()?;
        let claim = Claims(&conn).add(1, 2);
        assert_eq!(claim.is_err(), true);
        assert_eq!(Claims(&conn).all()?.len(), 0);
        Ok(())
    }
}