package templates

import (
	"embed"
	"encoding/json"
	"fmt"
	"github.com/wailsapp/wails/v3/internal/buildinfo"
	"github.com/wailsapp/wails/v3/internal/s"
	"github.com/wailsapp/wails/v3/internal/version"
	"io/fs"
	"os"
	"path/filepath"
	"runtime"
	"strings"

	"github.com/go-git/go-git/v5"
	"github.com/go-git/go-git/v5/plumbing"
	"github.com/pkg/errors"
	"github.com/pterm/pterm"
	"github.com/wailsapp/wails/v3/internal/debug"

	"github.com/wailsapp/wails/v3/internal/flags"

	"github.com/leaanthony/gosod"

	"github.com/samber/lo"
)

//go:embed *
var templates embed.FS

type TemplateData struct {
	Name        string
	Description string
	FS          fs.FS
}

var defaultTemplates = []TemplateData{}

func init() {
	dirs, err := templates.ReadDir(".")
	if err != nil {
		return
	}
	for _, dir := range dirs {
		if strings.HasPrefix(dir.Name(), "_") {
			continue
		}
		if dir.IsDir() {
			template, err := parseTemplate(templates, dir.Name())
			if err != nil {
				continue
			}
			defaultTemplates = append(defaultTemplates,
				TemplateData{
					Name:        dir.Name(),
					Description: template.Description,
					FS:          templates,
				})
		}
	}
}

func ValidTemplateName(name string) bool {
	return lo.ContainsBy(defaultTemplates, func(template TemplateData) bool {
		return template.Name == name
	})
}

func GetDefaultTemplates() []TemplateData {
	return defaultTemplates
}

type TemplateOptions struct {
	*flags.Init
	LocalModulePath string
	UseTypescript   bool
	WailsVersion    string
}

func getInternalTemplate(templateName string) (*Template, error) {
	templateData, found := lo.Find(defaultTemplates, func(template TemplateData) bool {
		return template.Name == templateName
	})

	if !found {
		return nil, nil
	}

	template, err := parseTemplate(templateData.FS, templateData.Name)
	if err != nil {
		return nil, err
	}
	template.source = sourceInternal
	return &template, nil
}

func getLocalTemplate(templateName string) (*Template, error) {
	var template Template
	var err error
	_, err = os.Stat(templateName)
	if err != nil {
		return nil, nil
	}

	template, err = parseTemplate(os.DirFS(templateName), "")
	if err != nil {
		println("err2 = ", err.Error())
		return nil, err
	}
	template.source = sourceLocal

	return &template, nil
}

type BaseTemplate struct {
	Name        string `json:"name" description:"The name of the template"`
	ShortName   string `json:"shortname" description:"The short name of the template"`
	Author      string `json:"author" description:"The author of the template"`
	Description string `json:"description" description:"The template description"`
	HelpURL     string `json:"helpurl" description:"The help url for the template"`
	Version     string `json:"version" description:"The version of the template" default:"v0.0.1"`
	Dir         string `json:"-" description:"The directory to generate the template" default:"."`
	Frontend    string `json:"-" description:"The frontend directory to migrate"`
}

type source int

const (
	sourceInternal source = 1
	sourceLocal    source = 2
	sourceRemote   source = 3
)

// Template holds data relating to a template including the metadata stored in template.yaml
type Template struct {
	BaseTemplate
	Schema uint8 `json:"schema"`

	// Other data
	FS      fs.FS `json:"-"`
	source  source
	tempDir string
}

func parseTemplate(template fs.FS, templateName string) (Template, error) {
	var result Template
	jsonFile := "template.json"
	if templateName != "" {
		jsonFile = templateName + "/template.json"
	}
	data, err := fs.ReadFile(template, jsonFile)
	if err != nil {
		return result, errors.Wrap(err, "Error parsing template")
	}
	err = json.Unmarshal(data, &result)
	if err != nil {
		return result, err
	}
	result.FS = template

	// We need to do a version check here
	if result.Schema == 0 {
		return result, fmt.Errorf("template not supported by wails 3. This template is probably for wails 2")
	}
	if result.Schema != 3 {
		return result, fmt.Errorf("template version %d is not supported by wails 3. Ensure 'version' is set to 3 in the `template.json` file", result.Version)
	}

	return result, nil
}

// Clones the given uri and returns the temporary cloned directory
func gitclone(uri string) (string, error) {
	// Create temporary directory
	dirname, err := os.MkdirTemp("", "wails-template-*")
	if err != nil {
		return "", err
	}

	// Parse remote template url and version number
	templateInfo := strings.Split(uri, "@")
	cloneOption := &git.CloneOptions{
		URL: templateInfo[0],
	}
	if len(templateInfo) > 1 {
		cloneOption.ReferenceName = plumbing.NewTagReferenceName(templateInfo[1])
	}

	_, err = git.PlainClone(dirname, false, cloneOption)

	return dirname, err

}

func getRemoteTemplate(uri string) (*Template, error) {
	// git clone to temporary dir
	var tempDir string
	tempDir, err := gitclone(uri)

	if err != nil {
		return nil, err
	}
	// Remove the .git directory
	err = os.RemoveAll(filepath.Join(tempDir, ".git"))
	if err != nil {
		return nil, err
	}

	templateFS := os.DirFS(tempDir)
	var parsedTemplate Template
	parsedTemplate, err = parseTemplate(templateFS, "")
	if err != nil {
		return nil, err
	}
	parsedTemplate.tempDir = tempDir
	parsedTemplate.source = sourceRemote
	return &parsedTemplate, nil
}

func Install(options *flags.Init) error {
	var wd = lo.Must(os.Getwd())
	var projectDir string
	if options.ProjectDir == "." || options.ProjectDir == "" {
		projectDir = wd
	} else {
		projectDir = options.ProjectDir
	}
	var err error
	projectDir, err = filepath.Abs(filepath.Join(projectDir, options.ProjectName))
	if err != nil {
		return err
	}

	buildInfo, err := buildinfo.Get()
	if err != nil {
		return err
	}

	// Calculate relative path from project directory to LocalModulePath
	var localModulePath string

	// Use module path if it is set
	if buildInfo.Development {
		var relativePath string
		// Check if the project directory and LocalModulePath are in the same drive
		if filepath.VolumeName(wd) != filepath.VolumeName(debug.LocalModulePath) {
			relativePath = debug.LocalModulePath
		} else {
			relativePath, err = filepath.Rel(projectDir, debug.LocalModulePath)
		}
		if err != nil {
			return err
		}
		localModulePath = filepath.ToSlash(relativePath + "/")
	}
	UseTypescript := strings.HasSuffix(options.TemplateName, "-ts")

	templateData := TemplateOptions{
		Init:            options,
		LocalModulePath: localModulePath,
		UseTypescript:   UseTypescript,
		WailsVersion:    version.String(),
	}

	defer func() {
		// if `template.json` exists, remove it
		_ = os.Remove(filepath.Join(templateData.ProjectDir, "template.json"))
	}()

	var template *Template

	if ValidTemplateName(options.TemplateName) {
		template, err = getInternalTemplate(options.TemplateName)
		if err != nil {
			return err
		}
	} else {
		template, err = getLocalTemplate(options.TemplateName)
		if err != nil {
			return err
		}
		if template == nil {
			template, err = getRemoteTemplate(options.TemplateName)
		}
	}

	if template == nil {
		return fmt.Errorf("invalid template name: %s. Use -l flag to view available templates or use a valid filepath / url to a template", options.TemplateName)
	}

	templateData.ProjectDir = projectDir

	// If project directory already exists and is not empty, error
	if _, err := os.Stat(templateData.ProjectDir); !os.IsNotExist(err) {
		// Check if the directory is empty
		files := lo.Must(os.ReadDir(templateData.ProjectDir))
		if len(files) > 0 {
			return fmt.Errorf("project directory '%s' already exists and is not empty", templateData.ProjectDir)
		}
	}

	if template.source == sourceRemote && !options.SkipWarning {
		var confirmed = confirmRemote(template)
		if !confirmed {
			return nil
		}
	}

	pterm.Printf("Creating project\n")
	pterm.Printf("----------------\n\n")
	table := pterm.TableData{
		{"Project Name", options.ProjectName},
		{"Project Directory", filepath.FromSlash(options.ProjectDir)},
		{"Template", template.Name},
		{"Template Source", template.HelpURL},
		{"Template Version", template.Version},
	}
	err = pterm.DefaultTable.WithData(table).Render()
	if err != nil {
		return err
	}

	switch template.source {
	case sourceInternal:
		tfs, err := fs.Sub(template.FS, options.TemplateName)
		if err != nil {
			return err
		}
		common, err := fs.Sub(templates, "_common")
		if err != nil {
			return err
		}
		err = gosod.New(common).Extract(options.ProjectDir, templateData)
		if err != nil {
			return err
		}
		err = gosod.New(tfs).Extract(options.ProjectDir, templateData)
		if err != nil {
			return err
		}
	case sourceLocal, sourceRemote:
		data := struct {
			TemplateOptions
			Dir                string
			Name               string
			BinaryName         string
			ProductName        string
			ProductDescription string
			ProductVersion     string
			ProductCompany     string
			ProductCopyright   string
			ProductComments    string
			ProductIdentifier  string
			Silent             bool
			Typescript         bool
		}{
			Name:               options.ProjectName,
			Silent:             true,
			ProductCompany:     options.ProductCompany,
			ProductName:        options.ProductName,
			ProductDescription: options.ProductDescription,
			ProductVersion:     options.ProductVersion,
			ProductIdentifier:  options.ProductIdentifier,
			ProductCopyright:   options.ProductCopyright,
			ProductComments:    options.ProductComments,
			Typescript:         templateData.UseTypescript,
			TemplateOptions:    templateData,
		}
		// If options.ProjectDir does not exist, create it
		if _, err := os.Stat(options.ProjectDir); os.IsNotExist(err) {
			err = os.Mkdir(options.ProjectDir, 0755)
			if err != nil {
				return err
			}
		}
		err = gosod.New(template.FS).Extract(options.ProjectDir, data)
		if err != nil {
			return err
		}

		if template.tempDir != "" {
			s.RMDIR(template.tempDir)
		}
	}

	// Change to project directory
	err = os.Chdir(templateData.ProjectDir)
	if err != nil {
		return err
	}

	pterm.Printf("\nProject '%s' created successfully.\n", options.ProjectName)

	return nil

}

func GenerateTemplate(options *BaseTemplate) error {
	if options.Name == "" {
		return fmt.Errorf("please provide a template name using the -name flag")
	}

	// Get current directory
	baseOutputDir, err := filepath.Abs(options.Dir)
	if err != nil {
		return err
	}
	outDir := filepath.Join(baseOutputDir, options.Name)

	// Extract base files
	_, filename, _, _ := runtime.Caller(0)
	basePath := filepath.Join(filepath.Dir(filename), "_common")
	s.COPYDIR2(basePath, outDir)
	s.RMDIR(filepath.Join(outDir, "build"))

	// Copy frontend
	targetFrontendPath := filepath.Join(outDir, "frontend")
	sourceFrontendPath := options.Frontend
	if sourceFrontendPath == "" {
		sourceFrontendPath = filepath.Join(filepath.Dir(filename), "base", "frontend")
	}
	s.COPYDIR2(sourceFrontendPath, targetFrontendPath)

	// Copy files from relative directory ../commands/build_assets
	// Get the path to THIS file
	assetPath := filepath.Join(filepath.Dir(filename), "..", "commands", "build_assets")
	assetdir := filepath.Join(outDir, "build")

	s.COPYDIR2(assetPath, assetdir)

	// Copy the template NEXTSTEPS.md
	s.COPY(filepath.Join(filepath.Dir(filename), "base", "NEXTSTEPS.md"), filepath.Join(outDir, "NEXTSTEPS.md"))

	// Write the template.json file
	templateJSON := filepath.Join(outDir, "template.json")
	// Marshall
	optionsJSON, err := json.MarshalIndent(&Template{
		BaseTemplate: *options,
		Schema:       3,
	}, "", "  ")
	if err != nil {
		return err
	}
	err = os.WriteFile(templateJSON, optionsJSON, 0o755)
	if err != nil {
		return err
	}

	fmt.Printf("Successfully generated template in %s\n", outDir)
	return nil
}

func confirmRemote(template *Template) bool {
	pterm.Println(pterm.LightRed("\n--- REMOTE TEMPLATES ---"))

	// Create boxes with the title positioned differently and containing different content
	pterm.Println(pterm.LightYellow("You are creating a project using a remote template.\nThe Wails project takes no responsibility for 3rd party templates.\nOnly use remote templates that you trust."))

	result, _ := pterm.DefaultInteractiveConfirm.WithConfirmText("Are you sure you want to continue?").WithConfirmText("y").WithRejectText("n").Show()

	return result
}