package types

import "fmt"

// ValueType represents the type of a value
type ValueType byte

const (
	TypeNull ValueType = iota
	TypeNumber
	TypeString
	TypeBoolean
	TypeTable
)

type Opcode byte

const (
	OpConstant Opcode = iota
	OpSetLocal
	OpGetLocal
	OpSetGlobal
	OpGetGlobal
	OpEcho
	OpNewTable
	OpSetIndex
	OpGetIndex
	OpDup
	OpPop
	OpEnterScope
	OpExitScope
	OpAdd
	OpSubtract
	OpMultiply
	OpDivide
	OpNegate
	OpJumpIfFalse
	OpJump
	OpEqual
	OpNotEqual
	OpLessThan
	OpGreaterThan
	OpLessEqual
	OpGreaterEqual
	OpNot
)

type Instruction struct {
	Opcode  Opcode
	Operand int
}

type Bytecode struct {
	Constants    []any
	Instructions []Instruction
}

type Value struct {
	Type ValueType
	Data any
}

// Equal checks if two values are equal
func (v Value) Equal(other Value) bool {
	if v.Type != other.Type {
		return false
	}

	switch v.Type {
	case TypeNull:
		return true // null == null
	case TypeNumber:
		return v.Data.(float64) == other.Data.(float64)
	case TypeString:
		return v.Data.(string) == other.Data.(string)
	case TypeBoolean:
		return v.Data.(bool) == other.Data.(bool)
	case TypeTable:
		return v.Data.(*Table).Equal(other.Data.(*Table))
	default:
		return false
	}
}

func NewNull() Value {
	return Value{Type: TypeNull, Data: nil}
}

func NewString(s string) Value {
	return Value{Type: TypeString, Data: s}
}

func NewNumber(n float64) Value {
	return Value{Type: TypeNumber, Data: n}
}

func NewBoolean(b bool) Value {
	return Value{Type: TypeBoolean, Data: b}
}

// TableEntry maintains insertion order
type TableEntry struct {
	Key   Value
	Value Value
}

// Table with ordered entries
type Table struct {
	Entries []TableEntry    // Preserves insertion order
	HashMap map[string]int  // Fast lookups for string keys
	NumMap  map[float64]int // Fast lookups for number keys
	BoolMap map[bool]int    // Fast lookups for boolean keys
	// We can't have a map for table keys since they're not comparable in Go
	// We'll handle table keys by linear search in Entries
}

// Equal compares two tables for equality
func (t *Table) Equal(other *Table) bool {
	if len(t.Entries) != len(other.Entries) {
		return false
	}

	// Check if every key-value pair in t exists in other
	for _, entry := range t.Entries {
		found := false
		for _, otherEntry := range other.Entries {
			if entry.Key.Equal(otherEntry.Key) && entry.Value.Equal(otherEntry.Value) {
				found = true
				break
			}
		}

		if !found {
			return false
		}
	}

	return true
}

func NewTable() *Table {
	return &Table{
		Entries: []TableEntry{},
		HashMap: make(map[string]int),
		NumMap:  make(map[float64]int),
		BoolMap: make(map[bool]int),
	}
}

func NewTableValue() Value {
	return Value{Type: TypeTable, Data: NewTable()}
}

// SetKey is a helper to generate a string representation of a key for maps
func (t *Table) SetKey(key Value) string {
	switch key.Type {
	case TypeString:
		return "s:" + key.Data.(string)
	case TypeNumber:
		return "n:" + fmt.Sprintf("%v", key.Data.(float64))
	case TypeBoolean:
		if key.Data.(bool) {
			return "b:true"
		}
		return "b:false"
	case TypeNull:
		return "null"
	case TypeTable:
		// For tables, we can use a simple hash or just indicate it's a table
		return "t:table" // This won't distinguish between different tables
	default:
		return "unknown"
	}
}

// TableSet preserves insertion order
func (t *Table) Set(key, value Value) {
	idx := -1

	// Check if the key is a table
	if key.Type == TypeTable {
		// For table keys, we need to do a linear search
		for i, entry := range t.Entries {
			if entry.Key.Type == TypeTable && entry.Key.Data.(*Table).Equal(key.Data.(*Table)) {
				idx = i
				break
			}
		}
	} else {
		// Use the existing maps for other types
		switch key.Type {
		case TypeString:
			if i, ok := t.HashMap[key.Data.(string)]; ok {
				idx = i
			}
		case TypeNumber:
			if i, ok := t.NumMap[key.Data.(float64)]; ok {
				idx = i
			}
		case TypeBoolean:
			if i, ok := t.BoolMap[key.Data.(bool)]; ok {
				idx = i
			}
		}
	}

	if idx >= 0 {
		// Update existing entry
		t.Entries[idx].Value = value
	} else {
		// Add new entry
		t.Entries = append(t.Entries, TableEntry{Key: key, Value: value})
		idx = len(t.Entries) - 1

		// Update lookup maps
		switch key.Type {
		case TypeString:
			t.HashMap[key.Data.(string)] = idx
		case TypeNumber:
			t.NumMap[key.Data.(float64)] = idx
		case TypeBoolean:
			t.BoolMap[key.Data.(bool)] = idx
		}
	}
}

func (t *Table) Get(key Value) Value {
	// Check if the key is a table
	if key.Type == TypeTable {
		// For table keys, we need to do a linear search
		for _, entry := range t.Entries {
			if entry.Key.Type == TypeTable && entry.Key.Data.(*Table).Equal(key.Data.(*Table)) {
				return entry.Value
			}
		}
		return NewNull()
	}

	// Use the existing maps for other types
	switch key.Type {
	case TypeString:
		if i, ok := t.HashMap[key.Data.(string)]; ok {
			return t.Entries[i].Value
		}
	case TypeNumber:
		if i, ok := t.NumMap[key.Data.(float64)]; ok {
			return t.Entries[i].Value
		}
	case TypeBoolean:
		if i, ok := t.BoolMap[key.Data.(bool)]; ok {
			return t.Entries[i].Value
		}
	}
	return NewNull()
}