package game

import (
	"sync"

	"thehouseoficarus/internal/item"
)

type CraftIndex struct {
	mu        sync.RWMutex
	byType    map[string][]*item.ItemDef
	bySubtype map[string][]*item.ItemDef
	byInput   map[string][]*item.ItemDef
	byStation map[string][]*item.ItemDef
}

func NewCraftIndex() *CraftIndex {
	return &CraftIndex{
		byType:    make(map[string][]*item.ItemDef),
		bySubtype: make(map[string][]*item.ItemDef),
		byInput:   make(map[string][]*item.ItemDef),
		byStation: make(map[string][]*item.ItemDef),
	}
}

func (idx *CraftIndex) Build(items []*item.ItemDef) {
	idx.mu.Lock()
	defer idx.mu.Unlock()

	idx.byType = make(map[string][]*item.ItemDef)
	idx.bySubtype = make(map[string][]*item.ItemDef)
	idx.byInput = make(map[string][]*item.ItemDef)
	idx.byStation = make(map[string][]*item.ItemDef)

	for _, def := range items {
		if len(def.Craft) == 0 {
			continue
		}
		for ci := range def.Craft {
			craft := &def.Craft[ci]
			t := craft.Type
			if t == "" {
				t = "combine"
			}
			idx.byType[t] = appendUnique(idx.byType[t], def)

			if craft.Subtype != "" {
				idx.bySubtype[craft.Subtype] = appendUnique(idx.bySubtype[craft.Subtype], def)
			}

			for _, e := range craft.Ingredients {
				for _, id := range e.Items {
					idx.byInput[id] = appendUnique(idx.byInput[id], def)
				}
			}

			for _, sid := range craft.Station {
				idx.byStation[sid] = appendUnique(idx.byStation[sid], def)
			}
		}
	}
}

func appendUnique(items []*item.ItemDef, item *item.ItemDef) []*item.ItemDef {
	for _, existing := range items {
		if existing == item {
			return items
		}
	}
	return append(items, item)
}

func (idx *CraftIndex) ByType(craftType string) []*item.ItemDef {
	idx.mu.RLock()
	defer idx.mu.RUnlock()
	items := idx.byType[craftType]
	out := make([]*item.ItemDef, len(items))
	copy(out, items)
	return out
}

func (idx *CraftIndex) BySubtype(subtype string) []*item.ItemDef {
	idx.mu.RLock()
	defer idx.mu.RUnlock()
	items := idx.bySubtype[subtype]
	out := make([]*item.ItemDef, len(items))
	copy(out, items)
	return out
}

func (idx *CraftIndex) ByStation(stationDefID string) []*item.ItemDef {
	idx.mu.RLock()
	defer idx.mu.RUnlock()
	items := idx.byStation[stationDefID]
	out := make([]*item.ItemDef, len(items))
	copy(out, items)
	return out
}

func (idx *CraftIndex) ByInput(itemID string) []*item.ItemDef {
	idx.mu.RLock()
	defer idx.mu.RUnlock()
	items := idx.byInput[itemID]
	out := make([]*item.ItemDef, len(items))
	copy(out, items)
	return out
}

func (idx *CraftIndex) FindByTwoInputs(itemA, itemB string) []*item.ItemDef {
	idx.mu.RLock()
	defer idx.mu.RUnlock()

	candidatesA := idx.byInput[itemA]
	if len(candidatesA) == 0 {
		return nil
	}

	candidateSetB := make(map[string]bool)
	for _, def := range idx.byInput[itemB] {
		candidateSetB[def.ID] = true
	}

	var results []*item.ItemDef
	for _, def := range candidatesA {
		if !candidateSetB[def.ID] {
			continue
		}
		for _, craft := range def.Craft {
			entryA := craftEntry(craft, itemA)
			entryB := craftEntry(craft, itemB)
			if entryA >= 0 && entryB >= 0 && entryA != entryB {
				results = append(results, def)
				break
			}
		}
	}
	return results
}

func (idx *CraftIndex) FindByStationInput(stationDefID, itemID string) []*item.ItemDef {
	idx.mu.RLock()
	defer idx.mu.RUnlock()

	var results []*item.ItemDef
	for _, def := range idx.byStation[stationDefID] {
		for _, craft := range def.Craft {
			if craftMatchesEntry(&craft, itemID) {
				results = append(results, def)
				break
			}
		}
	}
	return results
}

func craftEntry(craft item.CraftDef, itemID string) int {
	for ei, e := range craft.Ingredients {
		for _, id := range e.Items {
			if id == itemID {
				return ei
			}
		}
	}
	return -1
}

func craftMatchesEntry(c *item.CraftDef, itemID string) bool {
	if c == nil {
		return false
	}
	for _, e := range c.Ingredients {
		for _, id := range e.Items {
			if id == itemID {
				return true
			}
		}
	}
	return false
}

// craftHasAllItems reports whether every ingredient entry can be satisfied:
// one listed alternative covering the entry's full quantity (not merely one
// of each item being present — a recipe needing 15 feathers is not offered
// on 1). Resolves through craftIngredientSource so availability checks can
// never disagree with consumption.
func craftHasAllItems(c *item.CraftDef, countItem func(string) int) bool {
	return craftHasAllItemsQty(c, countItem)
}

// craftIngredientSource resolves one ingredient entry: the FIRST listed
// alternative the player holds in the entry's full (normalized) quantity,
// plus that quantity. Availability checks and consumption both resolve
// through this helper so they always pick the same alternative — an entry
// listing several alternatives (e.g. bucket or jug of water) consumes the
// one the check verified, never a partially-stocked other one.
// Returns "" when no alternative covers the quantity.
func craftIngredientSource(e *item.IngredientEntry, countItem func(string) int) (string, int) {
	qty := e.Quantity
	if qty <= 0 {
		qty = 1
	}
	for _, id := range e.Items {
		if countItem(id) >= qty {
			return id, qty
		}
	}
	return "", qty
}

func craftHasAllItemsQty(c *item.CraftDef, countItem func(string) int) bool {
	if c == nil {
		return false
	}
	for i := range c.Ingredients {
		if id, _ := craftIngredientSource(&c.Ingredients[i], countItem); id == "" {
			return false
		}
	}
	return true
}

// consumeIngredients removes one batch of every ingredient entry. Each
// entry consumes the same alternative the availability checks verify (the
// first one covering the FULL quantity), and consumption is two-pass:
// nothing is removed unless every entry resolves, so a craft can never
// partially consume an alternative and silently keep the rest. Callers that
// already ran a craftHasAllItems* check cannot see a false return; it
// guards callers whose own pre-check is weaker. Callers that check the
// result must abort the craft without producing output.
func consumeIngredients(c *item.CraftDef, countItem func(string) int, removeItem func(string, int) bool) bool {
	if c == nil {
		return true
	}
	type consumption struct {
		id  string
		qty int
	}
	plan := make([]consumption, 0, len(c.Ingredients))
	for i := range c.Ingredients {
		id, qty := craftIngredientSource(&c.Ingredients[i], countItem)
		if id == "" {
			return false
		}
		plan = append(plan, consumption{id: id, qty: qty})
	}
	for _, s := range plan {
		removeItem(s.id, s.qty)
	}
	return true
}