use lootalot_db::{self as db, DbConnection, QueryResult};

/// Every possible update which can happen during a query
#[derive(Serialize, Deserialize, Debug)]
pub enum Update {
    Wealth(db::Wealth),
    ItemAdded(db::Item),
    ItemRemoved(db::Item),
    ClaimAdded(db::Claim),
    ClaimRemoved(db::Claim),
}

/// Every value which can be queried
#[derive(Serialize, Deserialize, Debug)]
pub enum Value {
    Item(db::Item),
    Claim(db::Claim),
    ItemList(Vec<db::Item>),
    ClaimList(Vec<db::Claim>),
    PlayerList(Vec<db::Player>),
}

/// A generic response for all queries
#[derive(Serialize, Deserialize, Debug, Default)]
pub struct ApiResponse {
    /// The value requested, if any
    pub value: Option<Value>,
    /// A text to notify user, if relevant
    pub notification: Option<String>,
    /// A list of updates, if any
    pub updates: Option<Vec<Update>>,
    /// A text describing errors, if any
    pub errors: Option<String>,
}

impl ApiResponse {
    fn push_update(&mut self, update: Update) {
        if let Some(v) = self.updates.as_mut() {
            v.push(update);
        } else {
            self.updates = Some(vec![update]);
        }
    }

    fn push_error<S: Into<String>>(&mut self, error: S) {
        if let Some(errors) = self.errors.as_mut() {
            *errors = format!("{}\n{}", errors, error.into());
        } else {
            self.errors = Some(error.into())
        }
    }

    fn set_value(&mut self, value: Value) {
        self.value = Some(value);
    }

    fn notify<S: Into<String>>(&mut self, text: S) {
        self.notification = Some(text.into());
    }
}

pub enum ApiError {
    DieselError(diesel::result::Error),
    InvalidAction(String),
}

/// Every allowed queries on the database
pub enum ApiActions {
    FetchPlayers,
    FetchInventory,
    FetchClaims,
    // Player actions
    FetchLoot(i32),
    UpdateWealth(i32, f32),
    BuyItems(i32, Vec<(i32, Option<f32>)>),
    SellItems(i32, Vec<(i32, Option<f32>)>),
    ClaimItem(i32, i32),
    UnclaimItem(i32, i32),
    // Group actions
    AddLoot(Vec<db::Item>),
}

pub enum AdminActions {
    AddPlayer(String, f32),
    //AddInventoryItem(pub String, pub i32),
    ResolveClaims,
    //SetClaimsTimeout(pub i32),
}

pub fn execute(
    conn: &DbConnection,
    query: ApiActions,
) -> Result<ApiResponse, diesel::result::Error> {
    let mut response = ApiResponse::default();
    match query {
        ApiActions::FetchPlayers => {
            response.set_value(Value::PlayerList(db::Players(conn).all()?));
        }
        ApiActions::FetchInventory => {
            response.set_value(Value::ItemList(db::Inventory(conn).all()?));
        }
        ApiActions::FetchClaims => {
            response.set_value(Value::ClaimList(db::fetch_claims(conn)?));
        }
        ApiActions::FetchLoot(id) => {
            response.set_value(Value::ItemList(db::LootManager(conn, id).all()?));
        }
        ApiActions::UpdateWealth(id, amount) => {
            response.push_update(Update::Wealth(
                db::AsPlayer(conn, id).update_wealth(amount)?,
            ));
        }
        ApiActions::BuyItems(id, params) => {
            let mut cumulated_diff: Vec<db::Wealth> = Vec::with_capacity(params.len());
            let mut added_items: u16 = 0;
            for (item_id, price_mod) in params.into_iter() {
                // Use a transaction to avoid incoherant state in case of error
                if let Ok((item, diff)) = db::buy_item_from_inventory(conn, id, item_id, price_mod) {
                    cumulated_diff.push(diff);
                    response.push_update(Update::ItemAdded(item));
                    added_items += 1;
                } else {
                    response.push_error(format!("Error adding {}", item_id));
                }
            }
            response.notify(format!("Added {} items", added_items));
            response.push_update(Update::Wealth(
                cumulated_diff
                    .into_iter()
                    .fold(db::Wealth::from_gp(0.0), |acc, i| acc + i),
            ));
        }
        ApiActions::SellItems(id, params) => {
            let mut all_results: Vec<db::Wealth> = Vec::with_capacity(params.len());
            let mut sold_items: u16 = 0;
            for (loot_id, price_mod) in params.into_iter() {
                if let Ok((deleted, diff)) = db::sell_item_transaction(conn, id, loot_id, price_mod) {
                    all_results.push(diff);
                    response.push_update(Update::ItemRemoved(deleted));
                    sold_items += 1;
                } else {
                    response.push_error(format!("Error selling {}", loot_id));
                }
            }
            response.notify(format!("Sold {} items", sold_items));
            response.push_update(Update::Wealth(
                all_results
                    .into_iter()
                    .fold(db::Wealth::from_gp(0.0), |acc, i| acc + i),
            ));
        }
        ApiActions::ClaimItem(id, item) => {
            response.push_update(Update::ClaimAdded(
                db::Claims(conn).add(id, item)?,
            ));
        }
        ApiActions::UnclaimItem(id, item) => {
            response.push_update(Update::ClaimRemoved(
                db::Claims(conn).remove(id, item)?,
            ));
        }
        // Group actions
        ApiActions::AddLoot(items) => {}
    }
    Ok(response)
}