package object

import (
	"bytes"
	"fmt"
	"strings"
)

type HashKey struct {
	Type  Type
	Value uint64
}

type HashPair struct {
	Key   Object
	Value Object
}

type Hash struct {
	Pairs map[HashKey]HashPair
}

func (h *Hash) Len() int {
	return len(h.Pairs)
}

func (h *Hash) Bool() bool {
	return len(h.Pairs) > 0
}

func (h *Hash) Type() Type {
	return HashType
}

func (h *Hash) Inspect() string {
	var out bytes.Buffer

	pairs := []string{}
	for _, pair := range h.Pairs {
		pairs = append(pairs, fmt.Sprintf("%s: %s", pair.Key.Inspect(), pair.Value.Inspect()))
	}

	out.WriteString("{")
	out.WriteString(strings.Join(pairs, ", "))
	out.WriteString("}")

	return out.String()
}

func (h *Hash) String() string {
	return h.Inspect()
}

func (h *Hash) Add(other Object) (Object, error) {
	if other.Type() != h.Type() {
		return nil, NewBinaryOpError(h, other, "+")
	}

	pairs := make(map[HashKey]HashPair)
	for k, v := range h.Pairs {
		pairs[k] = v
	}
	for k, v := range other.(*Hash).Pairs {
		pairs[k] = v
	}
	return &Hash{Pairs: pairs}, nil
}

func (h *Hash) Get(index Object) (Object, error) {
	key, ok := index.(Hasher)
	if !ok {
		return nil, fmt.Errorf("invalid hash key %s", index.Type())
	}

	pair, found := h.Pairs[key.Hash()]
	if !found {
		return Null{}, nil
	}

	return pair.Value, nil
}

func (h *Hash) Set(index, other Object) error {
	key, ok := index.(Hasher)
	if !ok {
		return fmt.Errorf("invalid hash key %s", index.Type())
	}

	h.Pairs[key.Hash()] = HashPair{Key: index, Value: other}

	return nil
}

func (h *Hash) Compare(other Object) int {
	if obj, ok := other.(*Hash); ok {
		if len(h.Pairs) != len(obj.Pairs) {
			return -1
		}
		for _, pair := range h.Pairs {
			hashed := pair.Value.(Hasher)
			right, ok := obj.Pairs[hashed.Hash()]
			if !ok {
				return -1
			}
			val := pair.Value.Compare(right.Value)
			if val != 0 {
				return val
			}
		}

		return 0
	}
	return -1
}