package compiler

import (
	"fmt"

	"git.sharkk.net/Sharkk/Mako/parser"
)

// Compiler holds the compilation state and compiles AST to bytecode
type Compiler struct {
	current   *CompilerState // Current compilation state
	enclosing *CompilerState // Enclosing function state for closures
	errors    []CompileError // Compilation errors
}

// NewCompiler creates a new compiler instance
func NewCompiler() *Compiler {
	return &Compiler{
		current: NewCompilerState(FunctionTypeScript),
		errors:  make([]CompileError, 0),
	}
}

// Compile compiles a program AST to bytecode
func (c *Compiler) Compile(program *parser.Program) (*Chunk, []CompileError) {
	for _, stmt := range program.Statements {
		c.compileStatement(stmt)
	}

	c.current.EmitInstruction(OpReturnNil)

	if len(c.errors) > 0 {
		return nil, c.errors
	}

	return c.current.Chunk, nil
}

// Statement compilation
func (c *Compiler) compileStatement(stmt parser.Statement) {
	// Extract line from any statement that has position info
	if lineNode := c.getLineFromNode(stmt); lineNode != 0 {
		c.current.SetLine(lineNode)
	}

	switch s := stmt.(type) {
	case *parser.StructStatement:
		c.compileStructStatement(s)
	case *parser.MethodDefinition:
		c.compileMethodDefinition(s)
	case *parser.Assignment:
		c.compileAssignment(s)
	case *parser.ExpressionStatement:
		c.compileExpression(s.Expression)
		c.current.EmitInstruction(OpPop) // Discard result
	case *parser.EchoStatement:
		c.compileExpression(s.Value)
		c.current.EmitInstruction(OpEcho)
	case *parser.IfStatement:
		c.compileIfStatement(s)
	case *parser.WhileStatement:
		c.compileWhileStatement(s)
	case *parser.ForStatement:
		c.compileForStatement(s)
	case *parser.ForInStatement:
		c.compileForInStatement(s)
	case *parser.ReturnStatement:
		c.compileReturnStatement(s)
	case *parser.ExitStatement:
		c.compileExitStatement(s)
	case *parser.BreakStatement:
		c.current.EmitBreak()
	default:
		c.addError(fmt.Sprintf("unknown statement type: %T", stmt))
	}
}

// Expression compilation
func (c *Compiler) compileExpression(expr parser.Expression) {
	if lineNode := c.getLineFromNode(expr); lineNode != 0 {
		c.current.SetLine(lineNode)
	}

	switch e := expr.(type) {
	case *parser.Identifier:
		c.compileIdentifier(e)
	case *parser.NumberLiteral:
		c.compileNumberLiteral(e)
	case *parser.StringLiteral:
		c.compileStringLiteral(e)
	case *parser.BooleanLiteral:
		c.compileBooleanLiteral(e)
	case *parser.NilLiteral:
		c.compileNilLiteral(e)
	case *parser.TableLiteral:
		c.compileTableLiteral(e)
	case *parser.StructConstructor:
		c.compileStructConstructor(e)
	case *parser.FunctionLiteral:
		c.compileFunctionLiteral(e)
	case *parser.CallExpression:
		c.compileCallExpression(e)
	case *parser.PrefixExpression:
		c.compilePrefixExpression(e)
	case *parser.InfixExpression:
		c.compileInfixExpression(e)
	case *parser.IndexExpression:
		c.compileIndexExpression(e)
	case *parser.DotExpression:
		c.compileDotExpression(e)
	case *parser.Assignment:
		c.compileAssignmentExpression(e)
	default:
		c.addError(fmt.Sprintf("unknown expression type: %T", expr))
	}
}

// Literal compilation
func (c *Compiler) compileNumberLiteral(node *parser.NumberLiteral) {
	value := Value{Type: ValueNumber, Data: node.Value}
	index := c.current.AddConstant(value)
	if index == -1 {
		c.addError("too many constants")
		return
	}
	c.current.EmitInstruction(OpLoadConst, uint16(index))
}

func (c *Compiler) compileStringLiteral(node *parser.StringLiteral) {
	value := Value{Type: ValueString, Data: node.Value}
	index := c.current.AddConstant(value)
	if index == -1 {
		c.addError("too many constants")
		return
	}
	c.current.EmitInstruction(OpLoadConst, uint16(index))
}

func (c *Compiler) compileBooleanLiteral(node *parser.BooleanLiteral) {
	value := Value{Type: ValueBool, Data: node.Value}
	index := c.current.AddConstant(value)
	if index == -1 {
		c.addError("too many constants")
		return
	}
	c.current.EmitInstruction(OpLoadConst, uint16(index))
}

func (c *Compiler) compileNilLiteral(node *parser.NilLiteral) {
	value := Value{Type: ValueNil, Data: nil}
	index := c.current.AddConstant(value)
	if index == -1 {
		c.addError("too many constants")
		return
	}
	c.current.EmitInstruction(OpLoadConst, uint16(index))
}

// Identifier compilation
func (c *Compiler) compileIdentifier(node *parser.Identifier) {
	// Try local variables first
	slot := c.current.ResolveLocal(node.Value)
	if slot != -1 {
		if slot == -2 {
			c.addError("can't read local variable in its own initializer")
			return
		}
		c.current.EmitInstruction(OpLoadLocal, uint16(slot))
		return
	}

	// Try upvalues
	upvalue := c.resolveUpvalue(node.Value)
	if upvalue != -1 {
		c.current.EmitInstruction(OpGetUpvalue, uint16(upvalue))
		return
	}

	// Must be global
	value := Value{Type: ValueString, Data: node.Value}
	index := c.current.AddConstant(value)
	if index == -1 {
		c.addError("too many constants")
		return
	}
	c.current.EmitInstruction(OpLoadGlobal, uint16(index))
}

// Assignment compilation
func (c *Compiler) compileAssignment(node *parser.Assignment) {
	c.compileExpression(node.Value)

	switch target := node.Target.(type) {
	case *parser.Identifier:
		if node.IsDeclaration {
			// Check if we're at global scope
			if c.current.FunctionType == FunctionTypeScript && c.current.ScopeDepth == 0 {
				// Global variable declaration - treat as global assignment
				value := Value{Type: ValueString, Data: target.Value}
				index := c.current.AddConstant(value)
				if index == -1 {
					c.addError("too many constants")
					return
				}
				c.current.EmitInstruction(OpStoreGlobal, uint16(index))
			} else {
				// Local variable declaration
				if err := c.current.AddLocal(target.Value); err != nil {
					c.addError(err.Error())
					return
				}
				c.current.MarkInitialized()
			}
		} else {
			// Assignment to existing variable
			slot := c.current.ResolveLocal(target.Value)
			if slot != -1 {
				c.current.EmitInstruction(OpStoreLocal, uint16(slot))
			} else {
				upvalue := c.resolveUpvalue(target.Value)
				if upvalue != -1 {
					c.current.EmitInstruction(OpSetUpvalue, uint16(upvalue))
				} else {
					// Global assignment
					value := Value{Type: ValueString, Data: target.Value}
					index := c.current.AddConstant(value)
					if index == -1 {
						c.addError("too many constants")
						return
					}
					c.current.EmitInstruction(OpStoreGlobal, uint16(index))
				}
			}
		}
	case *parser.DotExpression:
		// table.field = value
		c.compileExpression(target.Left)
		value := Value{Type: ValueString, Data: target.Key}
		index := c.current.AddConstant(value)
		if index == -1 {
			c.addError("too many constants")
			return
		}
		c.current.EmitInstruction(OpSetField, uint16(index))
	case *parser.IndexExpression:
		// table[key] = value
		c.compileExpression(target.Left)
		c.compileExpression(target.Index)
		c.current.EmitInstruction(OpSetIndex)
	default:
		c.addError("invalid assignment target")
	}
}

func (c *Compiler) compileAssignmentExpression(node *parser.Assignment) {
	c.compileAssignment(node)
	// Assignment expressions leave the assigned value on stack
}

// Operator compilation
func (c *Compiler) compilePrefixExpression(node *parser.PrefixExpression) {
	c.compileExpression(node.Right)

	switch node.Operator {
	case "-":
		c.current.EmitInstruction(OpNeg)
	case "not":
		c.current.EmitInstruction(OpNot)
	default:
		c.addError(fmt.Sprintf("unknown prefix operator: %s", node.Operator))
	}
}

func (c *Compiler) compileInfixExpression(node *parser.InfixExpression) {
	// Handle short-circuit operators specially
	if node.Operator == "and" {
		c.compileExpression(node.Left)
		jump := c.current.EmitJump(OpJumpIfFalse)
		c.current.EmitInstruction(OpPop)
		c.compileExpression(node.Right)
		c.current.PatchJump(jump)
		return
	}

	if node.Operator == "or" {
		c.compileExpression(node.Left)
		elseJump := c.current.EmitJump(OpJumpIfFalse)
		endJump := c.current.EmitJump(OpJump)
		c.current.PatchJump(elseJump)
		c.current.EmitInstruction(OpPop)
		c.compileExpression(node.Right)
		c.current.PatchJump(endJump)
		return
	}

	// Regular binary operators
	c.compileExpression(node.Left)
	c.compileExpression(node.Right)

	switch node.Operator {
	case "+":
		c.current.EmitInstruction(OpAdd)
	case "-":
		c.current.EmitInstruction(OpSub)
	case "*":
		c.current.EmitInstruction(OpMul)
	case "/":
		c.current.EmitInstruction(OpDiv)
	case "==":
		c.current.EmitInstruction(OpEq)
	case "!=":
		c.current.EmitInstruction(OpNeq)
	case "<":
		c.current.EmitInstruction(OpLt)
	case "<=":
		c.current.EmitInstruction(OpLte)
	case ">":
		c.current.EmitInstruction(OpGt)
	case ">=":
		c.current.EmitInstruction(OpGte)
	default:
		c.addError(fmt.Sprintf("unknown infix operator: %s", node.Operator))
	}
}

// Control flow compilation
func (c *Compiler) compileIfStatement(node *parser.IfStatement) {
	c.compileExpression(node.Condition)

	// Jump over then branch if condition is false
	thenJump := c.current.EmitJump(OpJumpIfFalse)
	c.current.EmitInstruction(OpPop)

	// Compile then branch
	c.current.BeginScope()
	for _, stmt := range node.Body {
		c.compileStatement(stmt)
	}
	c.current.EndScope()

	// Jump over else branches
	elseJump := c.current.EmitJump(OpJump)
	c.current.PatchJump(thenJump)
	c.current.EmitInstruction(OpPop)

	// Compile elseif branches
	var elseifJumps []int
	for _, elseif := range node.ElseIfs {
		c.compileExpression(elseif.Condition)
		nextJump := c.current.EmitJump(OpJumpIfFalse)
		c.current.EmitInstruction(OpPop)

		c.current.BeginScope()
		for _, stmt := range elseif.Body {
			c.compileStatement(stmt)
		}
		c.current.EndScope()

		elseifJumps = append(elseifJumps, c.current.EmitJump(OpJump))
		c.current.PatchJump(nextJump)
		c.current.EmitInstruction(OpPop)
	}

	// Compile else branch
	if len(node.Else) > 0 {
		c.current.BeginScope()
		for _, stmt := range node.Else {
			c.compileStatement(stmt)
		}
		c.current.EndScope()
	}

	// Patch all jumps to end
	c.current.PatchJump(elseJump)
	for _, jump := range elseifJumps {
		c.current.PatchJump(jump)
	}
}

func (c *Compiler) compileWhileStatement(node *parser.WhileStatement) {
	c.current.EnterLoop()

	c.compileExpression(node.Condition)
	exitJump := c.current.EmitJump(OpJumpIfFalse)
	c.current.EmitInstruction(OpPop)

	c.current.BeginScope()
	for _, stmt := range node.Body {
		c.compileStatement(stmt)
	}
	c.current.EndScope()

	// Jump back to condition
	jump := len(c.current.Chunk.Code) - c.current.LoopStart + 2
	c.current.EmitInstruction(OpJump, uint16(jump))

	c.current.PatchJump(exitJump)
	c.current.EmitInstruction(OpPop)

	c.current.ExitLoop()
}

// For loop compilation
func (c *Compiler) compileForStatement(node *parser.ForStatement) {
	c.current.BeginScope()
	c.current.EnterLoop()

	// Initialize loop variable
	c.compileExpression(node.Start)
	if err := c.current.AddLocal(node.Variable.Value); err != nil {
		c.addError(err.Error())
		return
	}
	c.current.MarkInitialized()
	loopVar := len(c.current.Locals) - 1

	// Compile end value
	c.compileExpression(node.End)
	endSlot := len(c.current.Locals)
	if err := c.current.AddLocal("__end"); err != nil {
		c.addError(err.Error())
		return
	}
	c.current.MarkInitialized()

	// Compile step value (default 1)
	if node.Step != nil {
		c.compileExpression(node.Step)
	} else {
		value := Value{Type: ValueNumber, Data: float64(1)}
		index := c.current.AddConstant(value)
		if index == -1 {
			c.addError("too many constants")
			return
		}
		c.current.EmitInstruction(OpLoadConst, uint16(index))
	}
	stepSlot := len(c.current.Locals)
	if err := c.current.AddLocal("__step"); err != nil {
		c.addError(err.Error())
		return
	}
	c.current.MarkInitialized()

	// Loop condition: check if loop variable <= end (for positive step)
	conditionStart := len(c.current.Chunk.Code)
	c.current.EmitInstruction(OpLoadLocal, uint16(loopVar)) // Load loop var
	c.current.EmitInstruction(OpLoadLocal, uint16(endSlot)) // Load end
	c.current.EmitInstruction(OpLte)                        // Compare
	exitJump := c.current.EmitJump(OpJumpIfFalse)
	c.current.EmitInstruction(OpPop)

	// Loop body
	for _, stmt := range node.Body {
		c.compileStatement(stmt)
	}

	// Increment loop variable: var = var + step
	c.current.EmitInstruction(OpLoadLocal, uint16(loopVar))  // Load current value
	c.current.EmitInstruction(OpLoadLocal, uint16(stepSlot)) // Load step
	c.current.EmitInstruction(OpAdd)                         // Add
	c.current.EmitInstruction(OpStoreLocal, uint16(loopVar)) // Store back

	// Jump back to condition
	jumpBack := len(c.current.Chunk.Code) - conditionStart + 2
	c.current.EmitInstruction(OpJump, uint16(jumpBack))

	// Exit
	c.current.PatchJump(exitJump)
	c.current.EmitInstruction(OpPop)

	c.current.ExitLoop()
	c.current.EndScope()
}

// For-in loop compilation
func (c *Compiler) compileForInStatement(node *parser.ForInStatement) {
	c.current.BeginScope()
	c.current.EnterLoop()

	// Compile iterable and set up iterator
	c.compileExpression(node.Iterable)

	// For simplicity, assume table iteration
	// In a full implementation, we'd need to handle different iterator types

	// Create iterator variables
	if node.Key != nil {
		if err := c.current.AddLocal(node.Key.Value); err != nil {
			c.addError(err.Error())
			return
		}
		c.current.MarkInitialized()
	}

	if err := c.current.AddLocal(node.Value.Value); err != nil {
		c.addError(err.Error())
		return
	}
	c.current.MarkInitialized()

	// Loop condition (simplified - would need actual iterator logic)
	conditionStart := len(c.current.Chunk.Code)

	// For now, just emit a simple condition that will be false
	// In real implementation, this would call iterator methods
	nilValue := Value{Type: ValueNil, Data: nil}
	index := c.current.AddConstant(nilValue)
	if index == -1 {
		c.addError("too many constants")
		return
	}
	c.current.EmitInstruction(OpLoadConst, uint16(index))
	c.current.EmitInstruction(OpNot) // Convert nil to true, everything else to false

	exitJump := c.current.EmitJump(OpJumpIfFalse)
	c.current.EmitInstruction(OpPop)

	// Loop body
	for _, stmt := range node.Body {
		c.compileStatement(stmt)
	}

	// Jump back to condition
	jumpBack := len(c.current.Chunk.Code) - conditionStart + 2
	c.current.EmitInstruction(OpJump, uint16(jumpBack))

	// Exit
	c.current.PatchJump(exitJump)
	c.current.EmitInstruction(OpPop)

	c.current.ExitLoop()
	c.current.EndScope()
}

// Function compilation
func (c *Compiler) compileFunctionLiteral(node *parser.FunctionLiteral) {
	// Create new compiler state for function
	enclosing := c.current
	c.current = NewCompilerState(FunctionTypeFunction)
	c.current.parent = enclosing
	c.enclosing = enclosing

	// Begin function scope
	c.current.BeginScope()

	// Add parameters as local variables
	for _, param := range node.Parameters {
		if err := c.current.AddLocal(param.Name); err != nil {
			c.addError(err.Error())
			return
		}
		c.current.MarkInitialized()
	}

	// Compile function body
	for _, stmt := range node.Body {
		c.compileStatement(stmt)
	}

	// Implicit return nil if no explicit return
	c.current.EmitInstruction(OpReturnNil)

	// Create function object
	function := Function{
		Name:       "", // Anonymous function
		Arity:      len(node.Parameters),
		Variadic:   node.Variadic,
		LocalCount: len(c.current.Locals),
		UpvalCount: len(c.current.Upvalues),
		Chunk:      *c.current.Chunk,
		Defaults:   []Value{}, // TODO: Handle default parameters
	}

	// Add function to parent chunk
	functionIndex := len(enclosing.Chunk.Functions)
	enclosing.Chunk.Functions = append(enclosing.Chunk.Functions, function)

	// Restore enclosing state
	c.current = enclosing
	c.enclosing = nil

	// Emit closure instruction
	c.current.EmitInstruction(OpClosure, uint16(functionIndex), uint16(function.UpvalCount))
}

// Struct compilation
func (c *Compiler) compileStructStatement(node *parser.StructStatement) {
	// Convert parser fields to compiler fields
	fields := make([]StructField, len(node.Fields))
	for i, field := range node.Fields {
		fields[i] = StructField{
			Name:   field.Name,
			Type:   c.typeInfoToValueType(field.TypeHint),
			Offset: uint16(i),
		}
	}

	// Create struct definition
	structDef := Struct{
		Name:    node.Name,
		Fields:  fields,
		Methods: make(map[string]uint16),
		ID:      node.ID,
	}

	// Add to chunk
	c.current.Chunk.Structs = append(c.current.Chunk.Structs, structDef)
}

func (c *Compiler) compileMethodDefinition(node *parser.MethodDefinition) {
	// Compile method as a function
	enclosing := c.current
	c.current = NewCompilerState(FunctionTypeMethod)
	c.current.parent = enclosing
	c.enclosing = enclosing

	// Begin function scope
	c.current.BeginScope()

	// Add 'self' parameter
	if err := c.current.AddLocal("self"); err != nil {
		c.addError(err.Error())
		return
	}
	c.current.MarkInitialized()

	// Add method parameters
	for _, param := range node.Function.Parameters {
		if err := c.current.AddLocal(param.Name); err != nil {
			c.addError(err.Error())
			return
		}
		c.current.MarkInitialized()
	}

	// Compile method body
	for _, stmt := range node.Function.Body {
		c.compileStatement(stmt)
	}

	// Implicit return nil
	c.current.EmitInstruction(OpReturnNil)

	// Create function object
	function := Function{
		Name:       node.MethodName,
		Arity:      len(node.Function.Parameters) + 1, // +1 for self
		Variadic:   node.Function.Variadic,
		LocalCount: len(c.current.Locals),
		UpvalCount: len(c.current.Upvalues),
		Chunk:      *c.current.Chunk,
		Defaults:   []Value{},
	}

	// Add to parent chunk
	functionIndex := len(enclosing.Chunk.Functions)
	enclosing.Chunk.Functions = append(enclosing.Chunk.Functions, function)

	// Find struct and add method reference
	for i := range enclosing.Chunk.Structs {
		if enclosing.Chunk.Structs[i].ID == node.StructID {
			enclosing.Chunk.Structs[i].Methods[node.MethodName] = uint16(functionIndex)
			break
		}
	}

	// Restore state
	c.current = enclosing
	c.enclosing = nil
}

func (c *Compiler) compileStructConstructor(node *parser.StructConstructor) {
	// Create new struct instance
	c.current.EmitInstruction(OpNewStruct, node.StructID)

	// Initialize fields
	for _, field := range node.Fields {
		if field.Key != nil {
			// Named field assignment
			c.current.EmitInstruction(OpDup) // Duplicate struct reference

			// Get field name
			var fieldName string
			if ident, ok := field.Key.(*parser.Identifier); ok {
				fieldName = ident.Value
			} else if str, ok := field.Key.(*parser.StringLiteral); ok {
				fieldName = str.Value
			} else {
				c.addError("struct field names must be identifiers or strings")
				continue
			}

			// Find field index in struct definition
			fieldIndex := c.findStructFieldIndex(node.StructID, fieldName)
			if fieldIndex == -1 {
				c.addError(fmt.Sprintf("struct has no field '%s'", fieldName))
				continue
			}

			c.compileExpression(field.Value)
			c.current.EmitInstruction(OpSetProperty, uint16(fieldIndex))
		} else {
			// Positional field assignment (not typical for structs)
			c.addError("struct constructors require named field assignments")
		}
	}
}

// Table operations
func (c *Compiler) compileTableLiteral(node *parser.TableLiteral) {
	c.current.EmitInstruction(OpNewTable)

	for _, pair := range node.Pairs {
		if pair.Key == nil {
			// Array-style element
			c.compileExpression(pair.Value)
			c.current.EmitInstruction(OpTableInsert)
		} else {
			// Key-value pair
			c.current.EmitInstruction(OpDup) // Duplicate table reference
			c.compileExpression(pair.Key)
			c.compileExpression(pair.Value)
			c.current.EmitInstruction(OpSetIndex)
		}
	}
}

func (c *Compiler) compileDotExpression(node *parser.DotExpression) {
	c.compileExpression(node.Left)
	value := Value{Type: ValueString, Data: node.Key}
	index := c.current.AddConstant(value)
	if index == -1 {
		c.addError("too many constants")
		return
	}
	c.current.EmitInstruction(OpGetField, uint16(index))
}

func (c *Compiler) compileIndexExpression(node *parser.IndexExpression) {
	c.compileExpression(node.Left)
	c.compileExpression(node.Index)
	c.current.EmitInstruction(OpGetIndex)
}

// Function calls
func (c *Compiler) compileCallExpression(node *parser.CallExpression) {
	c.compileExpression(node.Function)

	// Compile arguments
	for _, arg := range node.Arguments {
		c.compileExpression(arg)
	}

	c.current.EmitInstruction(OpCall, uint16(len(node.Arguments)))
}

func (c *Compiler) compileReturnStatement(node *parser.ReturnStatement) {
	if node.Value != nil {
		c.compileExpression(node.Value)
		c.current.EmitInstruction(OpReturn)
	} else {
		c.current.EmitInstruction(OpReturnNil)
	}
}

func (c *Compiler) compileExitStatement(node *parser.ExitStatement) {
	if node.Value != nil {
		c.compileExpression(node.Value)
	} else {
		// Default exit code 0
		value := Value{Type: ValueNumber, Data: float64(0)}
		index := c.current.AddConstant(value)
		if index == -1 {
			c.addError("too many constants")
			return
		}
		c.current.EmitInstruction(OpLoadConst, uint16(index))
	}
	c.current.EmitInstruction(OpExit)
}

// Helper methods
func (c *Compiler) resolveUpvalue(name string) int {
	if c.enclosing == nil {
		return -1
	}

	local := c.enclosing.ResolveLocal(name)
	if local != -1 {
		c.enclosing.Locals[local].IsCaptured = true
		return c.current.AddUpvalue(uint8(local), true)
	}

	upvalue := c.resolveUpvalueInEnclosing(name)
	if upvalue != -1 {
		return c.current.AddUpvalue(uint8(upvalue), false)
	}

	return -1
}

func (c *Compiler) resolveUpvalueInEnclosing(name string) int {
	if c.enclosing == nil {
		return -1
	}

	// This would recursively check enclosing scopes
	// Simplified for now
	return -1
}

func (c *Compiler) typeInfoToValueType(typeInfo parser.TypeInfo) ValueType {
	switch typeInfo.Type {
	case parser.TypeNumber:
		return ValueNumber
	case parser.TypeString:
		return ValueString
	case parser.TypeBool:
		return ValueBool
	case parser.TypeNil:
		return ValueNil
	case parser.TypeTable:
		return ValueTable
	case parser.TypeFunction:
		return ValueFunction
	case parser.TypeStruct:
		return ValueStruct
	default:
		return ValueNil
	}
}

func (c *Compiler) findStructFieldIndex(structID uint16, fieldName string) int {
	for _, structDef := range c.current.Chunk.Structs {
		if structDef.ID == structID {
			for i, field := range structDef.Fields {
				if field.Name == fieldName {
					return i
				}
			}
			break
		}
	}
	return -1
}

// Enhanced error reporting
func (c *Compiler) addError(message string) {
	c.errors = append(c.errors, CompileError{
		Message: message,
		Line:    c.current.CurrentLine,
		Column:  0, // Column tracking would need more work
	})
}

// Error reporting
func (c *Compiler) Errors() []CompileError { return c.errors }
func (c *Compiler) HasErrors() bool        { return len(c.errors) > 0 }

// Helper to extract line info from AST nodes
func (c *Compiler) getLineFromNode(node any) int {
	// Since AST nodes don't store position, we'd need to modify the parser
	// For now, track during compilation by passing line info through
	return 0 // Placeholder
}

// Bytecode disassembler helper for debugging
func DisassembleInstruction(chunk *Chunk, offset int) int {
	if offset >= len(chunk.Code) {
		return offset
	}

	line := 0
	if offset < len(chunk.Lines) {
		line = chunk.Lines[offset]
	}

	fmt.Printf("%04d ", offset)
	if offset > 0 && line == chunk.Lines[offset-1] {
		fmt.Print("   | ")
	} else {
		fmt.Printf("%4d ", line)
	}

	op := Opcode(chunk.Code[offset])
	fmt.Printf("%-16s", opcodeNames[op])

	switch op {
	case OpLoadConst, OpLoadLocal, OpStoreLocal:
		operand := uint16(chunk.Code[offset+1]) | (uint16(chunk.Code[offset+2]) << 8)
		fmt.Printf(" %4d", operand)
		if op == OpLoadConst && int(operand) < len(chunk.Constants) {
			fmt.Printf(" '")
			printValue(chunk.Constants[operand])
			fmt.Printf("'")
		}
		return offset + 3
	case OpJump, OpJumpIfTrue, OpJumpIfFalse:
		jump := uint16(chunk.Code[offset+1]) | (uint16(chunk.Code[offset+2]) << 8)
		fmt.Printf(" %4d -> %d", jump, offset+3+int(jump))
		return offset + 3
	default:
		return offset + 1
	}
}

func printValue(value Value) {
	switch value.Type {
	case ValueNil:
		fmt.Print("nil")
	case ValueBool:
		fmt.Print(value.Data.(bool))
	case ValueNumber:
		fmt.Printf("%.2f", value.Data.(float64))
	case ValueString:
		fmt.Print(value.Data.(string))
	default:
		fmt.Printf("<%s>", valueTypeString(value.Type))
	}
}

func valueTypeString(vt ValueType) string {
	switch vt {
	case ValueTable:
		return "table"
	case ValueFunction:
		return "function"
	case ValueStruct:
		return "struct"
	case ValueArray:
		return "array"
	case ValueUpvalue:
		return "upvalue"
	default:
		return "unknown"
	}
}