package binding

import (
	"bytes"
	_ "embed"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"github.com/wailsapp/wails/v2/internal/fs"

	"github.com/leaanthony/slicer"
)

func (b *Bindings) GenerateGoBindings(baseDir string) error {
	store := b.db.store
	for packageName, structs := range store {
		packageDir := filepath.Join(baseDir, packageName)
		err := fs.Mkdir(packageDir)
		if err != nil {
			return err
		}
		for structName, methods := range structs {
			var jsoutput bytes.Buffer
			jsoutput.WriteString(`// @ts-check
// Cynhyrchwyd y ffeil hon yn awtomatig. PEIDIWCH Â MODIWL
// This file is automatically generated. DO NOT EDIT
`)
			var tsBody bytes.Buffer
			var tsContent bytes.Buffer
			tsContent.WriteString(`// Cynhyrchwyd y ffeil hon yn awtomatig. PEIDIWCH Â MODIWL
// This file is automatically generated. DO NOT EDIT
`)
			var importNamespaces slicer.StringSlicer
			for methodName, methodDetails := range methods {

				// Generate JS
				var args slicer.StringSlicer
				for count := range methodDetails.Inputs {
					arg := fmt.Sprintf("arg%d", count+1)
					args.Add(arg)
				}
				argsString := args.Join(", ")
				jsoutput.WriteString(fmt.Sprintf("\nexport function %s(%s) {", methodName, argsString))
				jsoutput.WriteString("\n")
				jsoutput.WriteString(fmt.Sprintf("  return window['go']['%s']['%s']['%s'](%s);", packageName, structName, methodName, argsString))
				jsoutput.WriteString("\n")
				jsoutput.WriteString(fmt.Sprintf("}"))
				jsoutput.WriteString("\n")

				// Generate TS
				tsBody.WriteString(fmt.Sprintf("\nexport function %s(", methodName))

				args.Clear()
				for count, input := range methodDetails.Inputs {
					arg := fmt.Sprintf("arg%d", count+1)
					args.Add(arg + ":" + goTypeToTypescriptType(input.TypeName))
					if strings.ContainsRune(input.TypeName, '.') {
						importNamespaces.Add(strings.Split(input.TypeName, ".")[0])
					}
				}
				tsBody.WriteString(args.Join(",") + "):")
				returnType := "Promise"
				if methodDetails.OutputCount() > 0 {
					firstType := goTypeToTypescriptType(methodDetails.Outputs[0].TypeName)
					returnType += "<" + firstType
					if methodDetails.OutputCount() == 2 {
						secondType := goTypeToTypescriptType(methodDetails.Outputs[1].TypeName)
						returnType += "|" + secondType
					}
					returnType += ">"
				} else {
					returnType = "Promise<void>"
				}
				tsBody.WriteString(returnType + ";\n")
			}

			importNamespaces.Deduplicate()
			importNamespaces.Each(func(namespace string) {
				tsContent.WriteString("import {" + namespace + "} from '../models';\n")
			})
			tsContent.WriteString(tsBody.String())

			jsfilename := filepath.Join(packageDir, structName+".js")
			err = os.WriteFile(jsfilename, jsoutput.Bytes(), 0755)
			if err != nil {
				return err
			}
			tsfilename := filepath.Join(packageDir, structName+".d.ts")
			err = os.WriteFile(tsfilename, tsContent.Bytes(), 0755)
			if err != nil {
				return err
			}
		}
	}
	err := b.WriteModels(baseDir)
	if err != nil {
		println(err)
		return err
	}
	return nil
}

func goTypeToJSDocType(input string) string {
	switch true {
	case input == "interface{}":
		return "any"
	case input == "string":
		return "string"
	case input == "error":
		return "Error"
	case
		strings.HasPrefix(input, "int"),
		strings.HasPrefix(input, "uint"),
		strings.HasPrefix(input, "float"):
		return "number"
	case input == "bool":
		return "boolean"
	case input == "[]byte":
		return "string"
	case strings.HasPrefix(input, "[]"):
		arrayType := goTypeToJSDocType(input[2:])
		return "Array<" + arrayType + ">"
	default:
		if strings.ContainsRune(input, '.') {
			return input
		}
		return "any"
	}
}

func goTypeToTypescriptType(input string) string {
	if strings.HasPrefix(input, "[]") {
		arrayType := goTypeToJSDocType(input[2:])
		return "Array<" + arrayType + ">"
	}
	return goTypeToJSDocType(input)
}