use std::convert::TryFrom;
use uuid::Uuid;
// use rand::prelude::*;

use postgres::transaction::Transaction;

use failure::Error;
use failure::err_msg;

use account;
use account::Account;

use construct::{Construct, construct_select, construct_write, construct_spawn};
use names::{name as generate_name};
use img;

pub const FREE_MTX: [MtxVariant; 1] = [
    MtxVariant::Rename,
];

pub const SHOP_LISTINGS: [Listing; 2] = [
    Listing { variant: MtxVariant::Molecular, credits: 10 },
    Listing { variant: MtxVariant::Invader, credits: 10 },
];

const NEW_IMAGE_COST: i64 = 1;
const NEW_NAME_COST: i64 = 5;
const NEW_CONSTRUCT_COST: i64 = 50;

#[derive(Debug,Clone,PartialEq,Serialize,Deserialize)]
pub struct Shop {
    owned: Vec<MtxVariant>,
    available: Vec<Listing>,
}

#[derive(Debug,Copy,Clone,PartialEq,Serialize,Deserialize)]
pub struct Listing {
    variant: MtxVariant,
    credits: u16,
}

#[derive(Debug,Copy,Clone,PartialEq,Serialize,Deserialize)]
pub enum MtxVariant {
    Rename,
    Molecular,
    Invader,
}

impl MtxVariant {
    fn to_sql(&self) -> String {
        format!("{:?}", *self)
    }
}

// could use postgres-derive
// but enums in pg are a bit of a pain
impl TryFrom<String> for MtxVariant {
    type Error = Error;
    fn try_from(v: String) -> Result<MtxVariant, Error> {
        match v.as_ref() {
            "Rename" => Ok(MtxVariant::Rename),
            "Molecular" => Ok(MtxVariant::Molecular),
            "Invader" => Ok(MtxVariant::Invader),
            _ => Err(format_err!("mtx variant not found variant={:?}", v)),
        }
    }
}

#[derive(Debug,Copy,Clone,Serialize,Deserialize)]
pub struct Mtx {
    id: Uuid,
    account: Uuid,
    variant: MtxVariant,
}

impl Mtx {
    pub fn new(variant: MtxVariant, account: Uuid) -> Mtx {
        match variant {
            _ => Mtx { id: Uuid::new_v4(), account, variant },
            // MtxVariant::Invader => Mtx { id: Uuid::new_v4(), account, variant: self },
            // MtxVariant::Molecular => Mtx { id: Uuid::new_v4(), account, variant: self },
        }
    }

    pub fn delete(tx: &mut Transaction, id: Uuid) -> Result<(), Error> {
        let query = "
            DELETE
            FROM mtx
            WHERE id = $1;
        ";

        let result = tx
            .execute(query, &[&id])?;

        if result != 1 {
            return Err(format_err!("unable to delete mtx {:?}", id));
        }

        info!("mtx deleted {:?}", id);

        return Ok(());
    }

    pub fn insert(&self, tx: &mut Transaction) -> Result<&Mtx, Error> {
        let query = "
            INSERT INTO mtx (id, account, variant)
            VALUES ($1, $2, $3)
            RETURNING id, account;
        ";

        let result = tx
            .query(query, &[&self.id, &self.account, &self.variant.to_sql()])?;

        result.iter().next().ok_or(err_msg("mtx not written"))?;

        info!("wrote mtx {:?}", self);

        return Ok(self);
    }

    // pub fn update(&self, tx: &mut Transaction) -> Result<&Mtx, Error> {
    //     let query = "
    //         UPDATE mtx
    //         SET data = $1, updated_at = now()
    //         WHERE id = $2
    //         RETURNING id, data;
    //     ";

    //     let result = tx
    //         .query(query, &[&self.id, &to_vec(self)?])?;

    //     if let None = result.iter().next() {
    //         return Err(err_msg("mtx not written"));
    //     }

    //     info!("wrote mtx {:?}", self);

    //     return Ok(self);
    // }
}

pub fn apply(tx: &mut Transaction, account: &Account, variant: MtxVariant, construct_id: Uuid, name: String) -> Result<Vec<Construct>, Error> {
    let mtx = select(tx, variant, account.id)?;
    let mut construct = construct_select(tx, construct_id, account.id)?;
    let cost = match mtx.variant {
        MtxVariant::Rename => NEW_NAME_COST,
        _ => NEW_IMAGE_COST,
    };
    account::debit(tx, account.id, cost)?;

    construct = match mtx.variant {
        MtxVariant::Rename => construct.new_name(name),
        _ => construct.new_img(),
    };
    match mtx.variant {
        MtxVariant::Invader => img::invader_write(construct.img)?,
        MtxVariant::Molecular => img::molecular_write(construct.img)?,
        _ => construct.img,
    };

    construct_write(tx, construct)?;
    account::team(tx, account)
}

pub fn select(tx: &mut Transaction, variant: MtxVariant, account: Uuid) -> Result<Mtx, Error> {
    let query = "
        SELECT id, account, variant
        FROM mtx
        WHERE account = $1
        AND variant = $2
        FOR UPDATE;
    ";

    let result = tx
        .query(query, &[&account, &variant.to_sql()])?;

    if let Some(row) = result.iter().next() {
        let id: Uuid = row.get(0);
        let account: Uuid = row.get(1);
        let v_str: String = row.get(2);
        let variant = MtxVariant::try_from(v_str)?;

        Ok(Mtx { id, account, variant })
    } else {
        Err(format_err!("mtx not found account={:?} variant={:?}", account, variant))
    }
}

pub fn new_construct(tx: &mut Transaction, account: &Account) -> Result<Construct, Error> {
    account::debit(tx, account.id, NEW_CONSTRUCT_COST)?;
    let construct = construct_spawn(tx, account.id, generate_name(), false)?;
    Ok(construct)
}

pub fn account_shop(tx: &mut Transaction, account: &Account) -> Result<Shop, Error> {
    let query = "
        SELECT id, variant
        FROM mtx
        WHERE account = $1;
    ";

    let result = tx
        .query(query, &[&account.id])?;

    let mut owned = vec![];

    for row in result.iter() {
        let id: Uuid = row.get(0);
        let v_str: String = row.get(1);
        let variant = match MtxVariant::try_from(v_str) {
            Ok(v) => v,
            Err(e) => {
                warn!("id={:?} {:?}", id, e);
                continue;
            },
        };
        owned.push(variant);
    };

    let available = SHOP_LISTINGS.iter()
        .filter(|l| !owned.contains(&l.variant))
        .map(|l| *l)
        .collect::<Vec<Listing>>();

    debug!("account shop acount={:?} owned={:?} available={:?}",
        account.name, owned, available);

    return Ok(Shop { owned, available });
}

pub fn buy(tx: &mut Transaction, account: &Account, mtx: MtxVariant) -> Result<Shop, Error> {
    let listing = SHOP_LISTINGS
        .iter()
        .find(|l| l.variant == mtx)
        .ok_or(format_err!("mtx variant not found variant={:?}", mtx))?;

    let account = account::debit(tx, account.id, listing.credits as i64)?;

    Mtx::new(mtx, account.id)
        .insert(tx)?;

    info!("account purchased mtx account={:?} mtx={:?} cost={:?} balance={:?}",
        account.name, mtx, listing.credits, account.balance);
    account_shop(tx, &account)
}