use crate::{
    assets::{self, AssetExt, AssetHandle},
    comp::{
        inventory::slot::InvSlotId,
        item::{
            modular, tool::AbilityMap, ItemBase, ItemDef, ItemKind, ItemTag, MaterialStatManifest,
        },
        Inventory, Item,
    },
    terrain::SpriteKind,
};
use hashbrown::HashMap;
use serde::{Deserialize, Serialize};
use std::sync::Arc;

#[derive(Clone, Debug, Serialize, Deserialize)]
pub enum RecipeInput {
    /// Only an item with a matching ItemDef can be used to satisfy this input
    Item(Arc<ItemDef>),
    /// Any items with this tag can be used to satisfy this input
    Tag(ItemTag),
    /// Similar to RecipeInput::Tag(_), but all items must be the same.
    /// Specifically this means that a mix of different items with the tag
    /// cannot be used.
    TagSameItem(ItemTag, u32),
    /// List is similar to tag, but has items defined in centralized file
    /// Similar to RecipeInput::TagSameItem(_), all items must be the same, they
    /// cannot be a mix of different items defined in the list.
    // Intent of using List over Tag is to make it harder for tag to be innocuously added to an
    // item breaking a recipe
    ListSameItem(Vec<Arc<ItemDef>>, u32),
}

#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct Recipe {
    pub output: (Arc<ItemDef>, u32),
    /// Input required for recipe, amount of input needed, whether input should
    /// be tracked as a modular component
    pub inputs: Vec<(RecipeInput, u32, bool)>,
    pub craft_sprite: Option<SpriteKind>,
}

impl Recipe {
    /// Perform a recipe, returning a list of missing items on failure
    pub fn craft_simple(
        &self,
        inv: &mut Inventory,
        // Vec tying an input to a slot
        slots: Vec<(u32, InvSlotId)>,
        ability_map: &AbilityMap,
        msm: &MaterialStatManifest,
    ) -> Result<Vec<Item>, Vec<(&RecipeInput, u32)>> {
        let mut slot_claims = HashMap::new();
        let mut unsatisfied_requirements = Vec::new();
        let mut component_slots = Vec::new();

        // Checks each input against slots in the inventory. If the slots contain an
        // item that fulfills the need of the input, marks some of the item as claimed
        // up to quantity needed for the crafting input. If the item either
        // cannot be used, or there is insufficient quantity, adds input and
        // number of materials needed to unsatisfied requirements.
        self.inputs
            .iter()
            .enumerate()
            .for_each(|(i, (input, mut required, mut is_component))| {
                // Check used for recipes that have an input that is not consumed, e.g.
                // craftsman hammer
                let mut contains_any = false;
                // Gets all slots provided for this input by the frontend
                let input_slots = slots
                    .iter()
                    .filter_map(|(j, slot)| if i as u32 == *j { Some(slot) } else { None });
                // Goes through each slot and marks some amount from each slot as claimed
                for slot in input_slots {
                    // Checks that the item in the slot can be used for the input
                    if let Some(item) = inv
                        .get(*slot)
                        .filter(|item| item.matches_recipe_input(input))
                    {
                        // Gets the number of items claimed from the slot, or sets to 0 if slot has
                        // not been claimed by another input yet
                        let claimed = slot_claims.entry(*slot).or_insert(0);
                        let available = item.amount().saturating_sub(*claimed);
                        let provided = available.min(required);
                        required -= provided;
                        *claimed += provided;
                        // If input is a component and provided amount from this slot at least 1,
                        // mark 1 piece as coming from that slot and set is_component to false to
                        // indicate it has been claimed.
                        if provided > 0 && is_component {
                            component_slots.push(*slot);
                            is_component = false;
                        }
                        contains_any = true;
                    }
                }
                // If there were not sufficient items to cover requirement between all provided
                // slots, or if non-consumed item was not present, mark input as not satisfied
                if required > 0 || !contains_any {
                    unsatisfied_requirements.push((input, required));
                }
            });

        // If there are no unsatisfied requirements, create the items produced by the
        // recipe in the necessary quantity and remove the items that the recipe
        // consumes
        if unsatisfied_requirements.is_empty() {
            let mut components = Vec::new();
            for slot in component_slots.iter() {
                let component = inv
                    .take(*slot, ability_map, msm)
                    .expect("Expected item to exist in the inventory");
                components.push(component);
                let to_remove = slot_claims
                    .get_mut(slot)
                    .expect("If marked in component slots, should be in slot claims");
                *to_remove -= 1;
            }
            for (slot, to_remove) in slot_claims.iter() {
                for _ in 0..*to_remove {
                    let _ = inv
                        .take(*slot, ability_map, msm)
                        .expect("Expected item to exist in the inventory");
                }
            }
            let (item_def, quantity) = &self.output;

            let mut crafted_item = Item::new_from_item_base(
                ItemBase::Raw(Arc::clone(item_def)),
                &[],
                ability_map,
                msm,
            );
            for component in components {
                crafted_item.add_component(component, ability_map, msm);
            }
            let mut crafted_items = Vec::with_capacity(*quantity as usize);
            for _ in 0..*quantity {
                crafted_items.push(crafted_item.duplicate(ability_map, msm));
            }
            Ok(crafted_items)
        } else {
            Err(unsatisfied_requirements)
        }
    }

    pub fn inputs(&self) -> impl ExactSizeIterator<Item = (&RecipeInput, u32, bool)> {
        self.inputs
            .iter()
            .map(|(item_def, amount, is_mod_comp)| (item_def, *amount, *is_mod_comp))
    }

    /// Determine whether the inventory contains the ingredients for a recipe.
    /// If it does, return a vec of  inventory slots that contain the
    /// ingredients needed, whose positions correspond to particular recipe
    /// inputs. If items are missing, return the missing items, and how many
    /// are missing.
    pub fn inventory_contains_ingredients(
        &self,
        inv: &Inventory,
    ) -> Result<Vec<(u32, InvSlotId)>, Vec<(&RecipeInput, u32)>> {
        // Hashmap tracking the quantity that needs to be removed from each slot (so
        // that it doesn't think a slot can provide more items than it contains)
        let mut slot_claims = HashMap::<InvSlotId, u32>::new();
        // Important to be a vec and to remain separate from slot_claims as it must
        // remain ordered, unlike the hashmap
        let mut slots = Vec::<(u32, InvSlotId)>::new();
        // The inputs to a recipe that have missing items, and the amount missing
        let mut missing = Vec::<(&RecipeInput, u32)>::new();

        for (i, (input, mut needed, _)) in self.inputs().enumerate() {
            let mut contains_any = false;
            // Checks through every slot, filtering to only those that contain items that
            // can satisfy the input
            for (inv_slot_id, slot) in inv.slots_with_id() {
                if let Some(item) = slot
                    .as_ref()
                    .filter(|item| item.matches_recipe_input(&*input))
                {
                    let claim = slot_claims.entry(inv_slot_id).or_insert(0);
                    slots.push((i as u32, inv_slot_id));
                    let can_claim = (item.amount().saturating_sub(*claim)).min(needed);
                    *claim += can_claim;
                    needed -= can_claim;
                    contains_any = true;
                }
            }

            if needed > 0 || !contains_any {
                missing.push((input, needed));
            }
        }

        if missing.is_empty() {
            Ok(slots)
        } else {
            Err(missing)
        }
    }
}

pub enum SalvageError {
    NotSalvageable,
}

pub fn try_salvage(
    inv: &mut Inventory,
    slot: InvSlotId,
    ability_map: &AbilityMap,
    msm: &MaterialStatManifest,
) -> Result<Vec<Item>, SalvageError> {
    if inv.get(slot).map_or(false, |item| item.is_salvageable()) {
        let salvage_item = inv.get(slot).expect("Expected item to exist in inventory");
        let salvage_output: Vec<_> = salvage_item
            .salvage_output()
            .map(Item::new_from_asset_expect)
            .collect();
        if salvage_output.is_empty() {
            // If no output items, assume salvaging was a failure
            // TODO: If we ever change salvaging to have a percent chance, remove the check
            // of outputs being empty (requires assets to exist for rock and wood materials
            // so that salvaging doesn't silently fail)
            Err(SalvageError::NotSalvageable)
        } else {
            // Remove item that is being salvaged
            let _ = inv
                .take(slot, ability_map, msm)
                .expect("Expected item to exist in inventory");
            // Return the salvaging output
            Ok(salvage_output)
        }
    } else {
        Err(SalvageError::NotSalvageable)
    }
}

pub enum ModularWeaponError {
    InvalidSlot,
    ComponentMismatch,
    DifferentTools,
    DifferentHands,
}

pub fn modular_weapon(
    inv: &mut Inventory,
    primary_component: InvSlotId,
    secondary_component: InvSlotId,
    ability_map: &AbilityMap,
    msm: &MaterialStatManifest,
) -> Result<Item, ModularWeaponError> {
    use modular::ModularComponent;
    // Closure to get inner modular component info from item in a given slot
    fn unwrap_modular(inv: &Inventory, slot: InvSlotId) -> Option<ModularComponent> {
        if let Some(ItemKind::ModularComponent(mod_comp)) =
            inv.get(slot).map(|item| item.kind()).as_deref()
        {
            // TODO: Remove
            Some(mod_comp.clone())
        } else {
            None
        }
    }

    // Checks if both components are comptabile, and if so returns the toolkind to
    // make weapon of
    let compatiblity = if let (Some(primary_component), Some(secondary_component)) = (
        unwrap_modular(inv, primary_component),
        unwrap_modular(inv, secondary_component),
    ) {
        // Checks that damage and held component slots each contain a damage and held
        // modular component respectively
        if let (
            ModularComponent::ToolPrimaryComponent {
                toolkind: tool_a,
                hand_restriction: hands_a,
                ..
            },
            ModularComponent::ToolSecondaryComponent {
                toolkind: tool_b,
                hand_restriction: hands_b,
                ..
            },
        ) = (primary_component, secondary_component)
        {
            // Checks that both components are of the same tool kind
            if tool_a == tool_b {
                // Checks that if both components have a hand restriction, they are the same
                let hands_check =
                    hands_a.map_or(true, |hands| hands_b.map_or(true, |hands2| hands == hands2));
                if hands_check {
                    Ok(tool_a)
                } else {
                    Err(ModularWeaponError::DifferentHands)
                }
            } else {
                Err(ModularWeaponError::DifferentTools)
            }
        } else {
            Err(ModularWeaponError::ComponentMismatch)
        }
    } else {
        Err(ModularWeaponError::InvalidSlot)
    };

    match compatiblity {
        Ok(tool_kind) => {
            // Remove components from inventory
            let primary_component = inv
                .take(primary_component, ability_map, msm)
                .expect("Expected component to exist");
            let secondary_component = inv
                .take(secondary_component, ability_map, msm)
                .expect("Expected component to exist");

            // Create modular weapon
            let components = vec![primary_component, secondary_component];
            Ok(Item::new_from_item_base(
                ItemBase::Modular(modular::ModularBase::Tool(tool_kind)),
                &components,
                ability_map,
                msm,
            ))
        },
        Err(err) => Err(err),
    }
}

#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct RecipeBook {
    recipes: HashMap<String, Recipe>,
}

impl RecipeBook {
    pub fn get(&self, recipe: &str) -> Option<&Recipe> { self.recipes.get(recipe) }

    pub fn iter(&self) -> impl ExactSizeIterator<Item = (&String, &Recipe)> { self.recipes.iter() }

    pub fn get_available(&self, inv: &Inventory) -> Vec<(String, Recipe)> {
        self.recipes
            .iter()
            .filter(|(_, recipe)| recipe.inventory_contains_ingredients(inv).is_ok())
            .map(|(name, recipe)| (name.clone(), recipe.clone()))
            .collect()
    }
}

#[derive(Clone, Debug, Serialize, Deserialize)]
pub enum RawRecipeInput {
    Item(String),
    Tag(ItemTag),
    TagSameItem(ItemTag),
    ListSameItem(String),
}

#[derive(Clone, Deserialize)]
pub(crate) struct RawRecipe {
    pub(crate) output: (String, u32),
    /// Input required for recipe, amount of input needed, whether input should
    /// be tracked as a modular component
    pub(crate) inputs: Vec<(RawRecipeInput, u32, bool)>,
    pub(crate) craft_sprite: Option<SpriteKind>,
}

#[derive(Clone, Deserialize)]
#[serde(transparent)]
pub(crate) struct RawRecipeBook(pub(crate) HashMap<String, RawRecipe>);

impl assets::Asset for RawRecipeBook {
    type Loader = assets::RonLoader;

    const EXTENSION: &'static str = "ron";
}

#[derive(Deserialize, Clone)]
pub struct ItemList(pub Vec<String>);

impl assets::Asset for ItemList {
    type Loader = assets::RonLoader;

    const EXTENSION: &'static str = "ron";
}

impl assets::Compound for RecipeBook {
    fn load<S: assets::source::Source + ?Sized>(
        cache: &assets::AssetCache<S>,
        specifier: &str,
    ) -> Result<Self, assets::BoxedError> {
        #[inline]
        fn load_item_def(spec: &(String, u32)) -> Result<(Arc<ItemDef>, u32), assets::Error> {
            let def = Arc::<ItemDef>::load_cloned(&spec.0)?;
            Ok((def, spec.1))
        }

        #[inline]
        fn load_recipe_input(
            (input, amount, is_mod_comp): &(RawRecipeInput, u32, bool),
        ) -> Result<(RecipeInput, u32, bool), assets::Error> {
            let def = match &input {
                RawRecipeInput::Item(name) => RecipeInput::Item(Arc::<ItemDef>::load_cloned(name)?),
                RawRecipeInput::Tag(tag) => RecipeInput::Tag(*tag),
                RawRecipeInput::TagSameItem(tag) => RecipeInput::TagSameItem(*tag, *amount),
                RawRecipeInput::ListSameItem(list) => {
                    let assets = &ItemList::load_expect(list).read().0;
                    let items = assets
                        .iter()
                        .map(|asset| Arc::<ItemDef>::load_expect_cloned(asset))
                        .collect();
                    RecipeInput::ListSameItem(items, *amount)
                },
            };
            Ok((def, *amount, *is_mod_comp))
        }

        let raw = cache.load::<RawRecipeBook>(specifier)?.cloned();

        let recipes = raw
            .0
            .iter()
            .map(
                |(
                    name,
                    RawRecipe {
                        output,
                        inputs,
                        craft_sprite,
                    },
                )| {
                    let inputs = inputs
                        .iter()
                        .map(load_recipe_input)
                        .collect::<Result<Vec<_>, _>>()?;
                    let output = load_item_def(output)?;
                    Ok((name.clone(), Recipe {
                        output,
                        inputs,
                        craft_sprite: *craft_sprite,
                    }))
                },
            )
            .collect::<Result<_, assets::Error>>()?;

        Ok(RecipeBook { recipes })
    }
}

pub fn default_recipe_book() -> AssetHandle<RecipeBook> {
    RecipeBook::load_expect("common.recipe_book")
}