package estransforms

import (
	"github.com/microsoft/typescript-go/internal/core"
	"github.com/microsoft/typescript-go/internal/transformers"
)

var (
	esDecoratorAndClassFields = transformers.Chain(newESDecoratorTransformer, newClassFieldsTransformer)
	NewESNextTransformer      = transformers.Chain(newUsingDeclarationTransformer, esDecoratorAndClassFields)
	// 2025: only module system syntax (import attributes, json modules), untransformed regex modifiers
	// 2024: no new downlevel syntax
	// 2023: no new downlevel syntax
	// 2022: class static blocks and class fields are handled by newClassFieldsTransformer
	NewES2021Transformer = transformers.Chain(NewESNextTransformer, newLogicalAssignmentTransformer)
	NewES2020Transformer = transformers.Chain(NewES2021Transformer, newNullishCoalescingTransformer, newOptionalChainTransformer)
	NewES2019Transformer = transformers.Chain(NewES2020Transformer, newOptionalCatchTransformer)
	NewES2018Transformer = transformers.Chain(NewES2019Transformer, newObjectRestSpreadTransformer, newforawaitTransformer, newTaggedTemplateLiftRestrictionTransformer)
	NewES2017Transformer = transformers.Chain(NewES2018Transformer, newAsyncTransformer)
	NewES2016Transformer = transformers.Chain(NewES2017Transformer, newExponentiationTransformer)
)

func GetESTransformer(opts *transformers.TransformOptions) *transformers.Transformer {
	options := opts.CompilerOptions
	switch options.GetEmitScriptTarget() {
	case core.ScriptTargetESNext:
		return esDecoratorAndClassFields(opts)
	case core.ScriptTargetES2025, core.ScriptTargetES2024, core.ScriptTargetES2023, core.ScriptTargetES2022, core.ScriptTargetES2021:
		return NewESNextTransformer(opts)
	case core.ScriptTargetES2020:
		return NewES2021Transformer(opts)
	case core.ScriptTargetES2019:
		return NewES2020Transformer(opts)
	case core.ScriptTargetES2018:
		return NewES2019Transformer(opts)
	case core.ScriptTargetES2017:
		return NewES2018Transformer(opts)
	case core.ScriptTargetES2016:
		return NewES2017Transformer(opts)
	default: // other, older, option, transform maximally
		return NewES2016Transformer(opts)
	}
}