package parser

import (
	"fmt"
	"reflect"
)

// readArray handles array parsing with full substruct support
func (p *Parser) readArray(field reflect.Value, fieldTag *FieldTag) error {
	var arraySize int
	if fieldTag.ArraySizeVar != "" {
		arraySize = p.getDynamicLength(fieldTag.ArraySizeVar)
	} else {
		size, err := p.readUint32()
		if err != nil {
			return err
		}
		arraySize = int(size)
	}

	if arraySize == 0 {
		return nil
	}

	if field.Kind() == reflect.Slice {
		elemType := field.Type().Elem()
		slice := reflect.MakeSlice(field.Type(), arraySize, arraySize)

		p.arrayStack = append(p.arrayStack, ArrayContext{
			elementType:  elemType,
			totalSize:    arraySize,
			sizeVariable: fieldTag.ArraySizeVar,
		})

		for i := 0; i < arraySize; i++ {
			p.arrayStack[len(p.arrayStack)-1].currentIndex = i
			elem := slice.Index(i)

			if elemType.Kind() == reflect.Struct {
				if err := p.parseStructElement(elem, elemType); err != nil {
					p.arrayStack = p.arrayStack[:len(p.arrayStack)-1]
					return fmt.Errorf("array element %d: %w", i, err)
				}
			} else {
				if err := p.readPrimitiveArrayElement(elem, elemType); err != nil {
					p.arrayStack = p.arrayStack[:len(p.arrayStack)-1]
					return fmt.Errorf("array element %d: %w", i, err)
				}
			}
		}

		p.arrayStack = p.arrayStack[:len(p.arrayStack)-1]
		field.Set(slice)
	}

	return nil
}

// readSubstruct handles substruct parsing
func (p *Parser) readSubstruct(field reflect.Value, length int) error {
	if field.Kind() == reflect.Slice {
		elemType := field.Type().Elem()
		slice := reflect.MakeSlice(field.Type(), length, length)

		for i := 0; i < length; i++ {
			elem := slice.Index(i)
			if err := p.parseStructElement(elem, elemType); err != nil {
				return fmt.Errorf("substruct element %d: %w", i, err)
			}
		}

		field.Set(slice)
		return nil
	} else if field.Kind() == reflect.Struct {
		return p.parseStructElement(field, field.Type())
	} else if field.Kind() == reflect.Ptr && field.Type().Elem().Kind() == reflect.Struct {
		structType := field.Type().Elem()
		newStruct := reflect.New(structType)
		if err := p.parseStructElement(newStruct.Elem(), structType); err != nil {
			return err
		}
		field.Set(newStruct)
		return nil
	}

	return fmt.Errorf("substruct field must be struct, slice of structs, or pointer to struct")
}

// parseStructElement parses a single struct element
func (p *Parser) parseStructElement(elem reflect.Value, elemType reflect.Type) error {
	oldStruct := p.currentStruct
	oldCache := p.fieldCache

	p.currentStruct = elem
	p.fieldCache = make(map[string]any)
	p.structStack = append(p.structStack, elem)

	for i := 0; i < elem.NumField(); i++ {
		field := elem.Field(i)
		fieldType := elemType.Field(i)

		if !field.CanSet() {
			continue
		}

		tag := fieldType.Tag.Get("eq2")
		if tag == "" || tag == "-" {
			continue
		}

		if err := p.parseField(field, tag); err != nil {
			p.structStack = p.structStack[:len(p.structStack)-1]
			p.currentStruct = oldStruct
			p.fieldCache = oldCache
			return fmt.Errorf("field %s: %w", fieldType.Name, err)
		}

		if field.CanInterface() {
			p.fieldCache[fieldType.Name] = field.Interface()
		}
	}

	p.structStack = p.structStack[:len(p.structStack)-1]
	p.currentStruct = oldStruct
	p.fieldCache = oldCache

	return nil
}

// readPrimitiveArrayElement reads primitive array elements
func (p *Parser) readPrimitiveArrayElement(elem reflect.Value, elemType reflect.Type) error {
	switch elemType.Kind() {
	case reflect.Uint8:
		val, err := p.readUint8()
		if err != nil {
			return err
		}
		elem.SetUint(uint64(val))
	case reflect.Uint16:
		val, err := p.readUint16()
		if err != nil {
			return err
		}
		elem.SetUint(uint64(val))
	case reflect.Uint32:
		val, err := p.readUint32()
		if err != nil {
			return err
		}
		elem.SetUint(uint64(val))
	case reflect.Uint64:
		val, err := p.readUint64()
		if err != nil {
			return err
		}
		elem.SetUint(val)
	case reflect.Int8:
		val, err := p.readUint8()
		if err != nil {
			return err
		}
		elem.SetInt(int64(int8(val)))
	case reflect.Int16:
		val, err := p.readUint16()
		if err != nil {
			return err
		}
		elem.SetInt(int64(int16(val)))
	case reflect.Int32:
		val, err := p.readUint32()
		if err != nil {
			return err
		}
		elem.SetInt(int64(int32(val)))
	case reflect.Int64:
		val, err := p.readUint64()
		if err != nil {
			return err
		}
		elem.SetInt(int64(val))
	case reflect.Float32:
		val, err := p.readFloat32()
		if err != nil {
			return err
		}
		elem.SetFloat(float64(val))
	case reflect.Float64:
		val, err := p.readFloat64()
		if err != nil {
			return err
		}
		elem.SetFloat(val)
	default:
		return fmt.Errorf("unsupported primitive array element type: %v", elemType.Kind())
	}

	return nil
}

// GetCurrentArrayIndex returns current array index for nested parsing
func (p *Parser) GetCurrentArrayIndex() int {
	if len(p.arrayStack) > 0 {
		return p.arrayStack[len(p.arrayStack)-1].currentIndex
	}
	return -1
}

// GetCurrentArraySize returns current array size
func (p *Parser) GetCurrentArraySize() int {
	if len(p.arrayStack) > 0 {
		return p.arrayStack[len(p.arrayStack)-1].totalSize
	}
	return 0
}