use std::cmp::Ordering;
use libpso::character::character;
use crate::ship::items::ClientItemId;
use crate::entity::item::{Meseta, ItemEntityId, ItemDetail, ItemEntity, BankEntity, BankItemEntity, BankName};
use std::future::Future;

use crate::entity::character::CharacterEntityId;
use crate::ship::items::state::ItemStateError;
use crate::ship::items::state::{IndividualItemDetail, StackedItemDetail, AddItemResult};
use crate::ship::items::inventory::{InventoryItem, InventoryItemDetail};


#[derive(thiserror::Error, Debug)]
pub enum BankError {
    #[error("bank full")]
    BankFull,
    #[error("stack full")]
    StackFull,
    #[error("meseta full")]
    MesetaFull,
}


#[derive(Clone, Debug)]
pub enum BankItemDetail {
    Individual(IndividualItemDetail),
    Stacked(StackedItemDetail),
}

impl BankItemDetail {
    fn stacked_mut(&mut self) -> Option<&mut StackedItemDetail> {
        match self {
            BankItemDetail::Stacked(sitem) => Some(sitem),
            _ => None,
        }
    }

    pub fn as_client_bytes(&self) -> [u8; 16] {
        match self {
            BankItemDetail::Individual(item) => {
                match &item.item {
                    ItemDetail::Weapon(w) => w.as_bytes(),
                    ItemDetail::Armor(a) => a.as_bytes(),
                    ItemDetail::Shield(s) => s.as_bytes(),
                    ItemDetail::Unit(u) => u.as_bytes(),
                    ItemDetail::Tool(t) => t.as_individual_bytes(),
                    ItemDetail::TechniqueDisk(d) => d.as_bytes(),
                    ItemDetail::Mag(m) => m.as_bytes(),
                    ItemDetail::ESWeapon(e) => e.as_bytes(),
                }
            },
            BankItemDetail::Stacked(item) => {
                item.tool.as_stacked_bytes(item.entity_ids.len())
            },
        }
    }
}


#[derive(Clone, Debug)]
pub struct BankItem {
    pub item_id: ClientItemId,
    pub item: BankItemDetail,
}

impl BankItem {
    pub async fn with_entity_id<F, Fut, T>(&self, mut param: T, mut func: F) -> Result<T, ItemStateError>
    where
        F: FnMut(T, ItemEntityId) -> Fut,
        Fut: Future<Output=Result<T, ItemStateError>>,
    {
        match &self.item {
            BankItemDetail::Individual(individual_item) => {
                param = func(param, individual_item.entity_id).await?;
            },
            BankItemDetail::Stacked(stacked_item) => {
                for entity_id in &stacked_item.entity_ids {
                    param = func(param, *entity_id).await?;
                }
            }
        }
        Ok(param)
    }
}


#[derive(Clone, Debug)]
pub struct Bank(Vec<BankItem>);

impl Bank {
    pub fn new(items: Vec<BankItem>) -> Bank {
        Bank(items)
    }
}

#[derive(Clone, Debug)]
pub struct BankState {
    pub character_id: CharacterEntityId,
    pub item_id_counter: u32,
    pub name: BankName,
    pub bank: Bank,
    pub meseta: Meseta,
}

impl BankState {
    pub fn new(character_id: CharacterEntityId, name: BankName, mut bank: Bank, meseta: Meseta) -> BankState {
        bank.0.sort();
        BankState {
            character_id,
            item_id_counter: 0,
            name,
            bank,
            meseta,
        }
    }

    pub fn count(&self) -> usize {
        self.bank.0.len()
    }

    pub fn initialize_item_ids(&mut self, base_item_id: u32) {
        for (i, item) in self.bank.0.iter_mut().enumerate() {
            item.item_id = ClientItemId(base_item_id + i as u32);
        }
        self.item_id_counter = base_item_id + self.bank.0.len() as u32;
    }

    pub fn add_meseta(&mut self, amount: u32) -> Result<(), ItemStateError> {
        if self.meseta.0 + amount > 999999 {
            return Err(ItemStateError::FullOfMeseta)
        }
        self.meseta.0 += amount;
        Ok(())
    }

    pub fn remove_meseta(&mut self, amount: u32) -> Result<(), ItemStateError> {
        if amount > self.meseta.0 {
            return Err(ItemStateError::InvalidMesetaRemoval(amount))
        }
        self.meseta.0 -= amount;
        Ok(())
    }

    pub fn add_inventory_item(&mut self, item: InventoryItem) -> Result<AddItemResult, BankError> {
        match item.item {
            InventoryItemDetail::Individual(iitem) => {
                if self.bank.0.len() >= 30 {
                    Err(BankError::BankFull)
                }
                else {
                    self.bank.0.push(BankItem {
                        item_id: item.item_id,
                        item: BankItemDetail::Individual(iitem)
                    });
                    self.bank.0.sort();
                    Ok(AddItemResult::NewItem)
                }
            },
            InventoryItemDetail::Stacked(sitem) => {
                let existing_stack = self.bank.0
                    .iter_mut()
                    .filter_map(|item| item.item.stacked_mut())
                    .find(|item| {
                        item.tool == sitem.tool
                    });
                match existing_stack {
                    Some(existing_stack) => {
                        if existing_stack.entity_ids.len() + sitem.entity_ids.len() > sitem.tool.max_stack() {
                            Err(BankError::StackFull)
                        }
                        else {
                            existing_stack.entity_ids.append(&mut sitem.entity_ids.clone());
                            Ok(AddItemResult::AddToStack)
                        }
                    },
                    None => {
                        if self.bank.0.len() >= 30 {
                            Err(BankError::BankFull)
                        }
                        else {
                            self.bank.0.push(BankItem {
                                item_id: item.item_id,
                                item: BankItemDetail::Stacked(sitem)
                            });
                            self.bank.0.sort();
                            Ok(AddItemResult::NewItem)
                        }
                    }
                }
            }
        }
    }

    pub fn take_item(&mut self, item_id: &ClientItemId, amount: u32) -> Option<BankItem> {
        let idx = self.bank.0
            .iter()
            .position(|i| i.item_id == *item_id)?;
        match &mut self.bank.0[idx].item {
            BankItemDetail::Individual(_individual_item) => {
                Some(self.bank.0.remove(idx))
            },
            BankItemDetail::Stacked(stacked_item) => {
                let remove_all = match stacked_item.entity_ids.len().cmp(&(amount as usize)) {
                    Ordering::Equal => true,
                    Ordering::Greater => false,
                    Ordering::Less => return None,
                };

                if remove_all {
                    Some(self.bank.0.remove(idx))
                }
                else {
                    let entity_ids = stacked_item.entity_ids.drain(..(amount as usize)).collect();
                    self.item_id_counter += 1;
                    Some(BankItem {
                        item_id: ClientItemId(self.item_id_counter),
                        item: BankItemDetail::Stacked(StackedItemDetail {
                            entity_ids,
                            tool: stacked_item.tool,
                        })})
                }
            }
        }
    }

    pub fn as_client_bank_items(&self) -> character::Bank {
        self.bank.0.iter()
            .enumerate()
            .fold(character::Bank::default(), |mut bank, (slot, item)| {
                bank.item_count = (slot + 1) as u32;
                let bytes = item.item.as_client_bytes();
                bank.items[slot].data1.copy_from_slice(&bytes[0..12]);
                bank.items[slot].data2.copy_from_slice(&bytes[12..16]);
                bank.items[slot].item_id = item.item_id.0;

                bank
            })
    }

    pub fn as_client_bank_request(&self) -> Vec<character::BankItem> {
        self.bank.0.iter()
            .map(|item| {
                let bytes = item.item.as_client_bytes();
                let mut data1 = [0; 12];
                let mut data2 = [0; 4];
                data1.copy_from_slice(&bytes[0..12]);
                data2.copy_from_slice(&bytes[12..16]);
                let amount = match &item.item {
                    BankItemDetail::Individual(_individual_bank_item) => {
                        1
                    },
                    BankItemDetail::Stacked(stacked_bank_item) => {
                        stacked_bank_item.count()
                    },
                };
                character::BankItem {
                    data1,
                    data2,
                    item_id: item.item_id.0,
                    amount: amount as u16,
                    flags: 1,
                }
            })
            .collect()
    }

    pub fn as_bank_entity(&self) -> BankEntity {
        BankEntity {
            items: self.bank.0.iter()
                .map(|item| {
                    match &item.item {
                        BankItemDetail::Individual(item) => {
                            BankItemEntity::Individual(ItemEntity {
                                id: item.entity_id,
                                item: item.item.clone(),
                            })
                        },
                        BankItemDetail::Stacked(items) => {
                            BankItemEntity::Stacked(items.entity_ids.iter()
                                                    .map(|id| {
                                                        ItemEntity {
                                                            id: *id,
                                                            item: ItemDetail::Tool(items.tool)
                                                        }
                                                    })
                                                    .collect())
                        },
                    }
                })
                .collect()
        }
    }
}

impl std::cmp::PartialEq for BankItem {
    fn eq(&self, other: &BankItem) -> bool {
        let mut self_bytes = [0u8; 4];
        let mut other_bytes = [0u8; 4];
        self_bytes.copy_from_slice(&self.item.as_client_bytes()[0..4]);
        other_bytes.copy_from_slice(&other.item.as_client_bytes()[0..4]);

        let self_value = u32::from_be_bytes(self_bytes);
        let other_value = u32::from_be_bytes(other_bytes);

        self_value.eq(&other_value)
    }
}

impl std::cmp::Eq for BankItem {}

impl std::cmp::PartialOrd for BankItem {
    fn partial_cmp(&self, other: &BankItem) -> Option<std::cmp::Ordering> {
        let mut self_bytes = [0u8; 4];
        let mut other_bytes = [0u8; 4];
        self_bytes.copy_from_slice(&self.item.as_client_bytes()[0..4]);
        other_bytes.copy_from_slice(&other.item.as_client_bytes()[0..4]);


        let self_value = u32::from_be_bytes(self_bytes);
        let other_value = u32::from_be_bytes(other_bytes);

        self_value.partial_cmp(&other_value)
    }
}

impl std::cmp::Ord for BankItem {
    fn cmp(&self, other: &BankItem) -> std::cmp::Ordering {
        let mut self_bytes = [0u8; 4];
        let mut other_bytes = [0u8; 4];
        self_bytes.copy_from_slice(&self.item.as_client_bytes()[0..4]);
        other_bytes.copy_from_slice(&other.item.as_client_bytes()[0..4]);


        let self_value = u32::from_le_bytes(self_bytes);
        let other_value = u32::from_le_bytes(other_bytes);

        self_value.cmp(&other_value)
    }
}