// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package codegen

import (
	"io"
	"os"
	"path/filepath"
	"text/template"

	"fidl/compiler/backend/common"
	"fidl/compiler/backend/types"

	"fidlgen_rust/ir"
	"fidlgen_rust/templates"
)

type Generator struct {
	tmpls *template.Template
}

func NewGenerator() *Generator {
	tmpls := template.New("RustTemplates")
	template.Must(tmpls.Parse(templates.SourceFile))
	template.Must(tmpls.Parse(templates.Bits))
	template.Must(tmpls.Parse(templates.Const))
	template.Must(tmpls.Parse(templates.Enum))
	template.Must(tmpls.Parse(templates.Protocol))
	template.Must(tmpls.Parse(templates.Service))
	template.Must(tmpls.Parse(templates.Struct))
	template.Must(tmpls.Parse(templates.Union))
	template.Must(tmpls.Parse(templates.Table))
	template.Must(tmpls.Parse(templates.Result))
	template.Must(tmpls.Parse(templates.Bits))
	return &Generator{
		tmpls: tmpls,
	}
}

func (gen *Generator) GenerateImpl(wr io.Writer, tree ir.Root) error {
	return gen.tmpls.ExecuteTemplate(wr, "GenerateSourceFile", tree)
}

func (gen *Generator) GenerateFidl(fidl types.Root, outputFilename, rustfmtPath, rustfmtConfigPath string) error {
	tree := ir.Compile(fidl)
	if err := os.MkdirAll(filepath.Dir(outputFilename), os.ModePerm); err != nil {
		return err
	}

	generated, err := os.Create(outputFilename)
	if err != nil {
		return err
	}

	var args []string
	if rustfmtConfigPath != "" {
		args = append(args, "--config-path", rustfmtConfigPath)
	}
	generatedPipe, err := common.NewFormatter(rustfmtPath, args...).FormatPipe(generated)
	if err != nil {
		return err
	}

	if err := gen.GenerateImpl(generatedPipe, tree); err != nil {
		return err
	}

	return generatedPipe.Close()
}