package cmd

import (
	"fmt"
	"io/ioutil"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"strings"
	"time"

	"github.com/leaanthony/mewn"
	"github.com/leaanthony/mewn/lib"
	"github.com/leaanthony/slicer"
	"github.com/leaanthony/spinner"
)

var fs = NewFSHelper()

// ValidateFrontendConfig checks if the frontend config is valid
func ValidateFrontendConfig(projectOptions *ProjectOptions) error {
	if projectOptions.FrontEnd.Dir == "" {
		return fmt.Errorf("Frontend directory not set in project.json")
	}
	if projectOptions.FrontEnd.Build == "" {
		return fmt.Errorf("Frontend build command not set in project.json")
	}
	if projectOptions.FrontEnd.Install == "" {
		return fmt.Errorf("Frontend install command not set in project.json")
	}
	if projectOptions.FrontEnd.Bridge == "" {
		return fmt.Errorf("Frontend bridge config not set in project.json")
	}

	return nil
}

// InstallGoDependencies will run go get in the current directory
func InstallGoDependencies(verbose bool) error {
	var depSpinner *spinner.Spinner
	if !verbose {
		depSpinner = spinner.New("Ensuring Dependencies are up to date...")
		depSpinner.SetSpinSpeed(50)
		depSpinner.Start()
	}
	err := NewProgramHelper(verbose).RunCommand("go get")
	if err != nil {
		if !verbose {
			depSpinner.Error()
		}
		return err
	}
	if !verbose {
		depSpinner.Success()
	}
	return nil
}

// EmbedAssets will embed the built frontend assets via mewn.
func EmbedAssets() ([]string, error) {
	mewnFiles := lib.GetMewnFiles([]string{}, false)

	referencedAssets, err := lib.GetReferencedAssets(mewnFiles)
	if err != nil {
		return []string{}, err
	}

	targetFiles := []string{}

	for _, referencedAsset := range referencedAssets {
		packfileData, err := lib.GeneratePackFileString(referencedAsset, false)
		if err != nil {
			return []string{}, err
		}
		targetFile := filepath.Join(referencedAsset.BaseDir, referencedAsset.PackageName+"-mewn.go")
		targetFiles = append(targetFiles, targetFile)
		ioutil.WriteFile(targetFile, []byte(packfileData), 0644)
	}

	return targetFiles, nil
}

// BuildApplication will attempt to build the project based on the given inputs
func BuildApplication(binaryName string, forceRebuild bool, buildMode string, packageApp bool, projectOptions *ProjectOptions) error {

	// Generate Windows assets if needed
	if runtime.GOOS == "windows" {
		cleanUp := !packageApp
		err := NewPackageHelper().PackageWindows(projectOptions, cleanUp)
		if err != nil {
			return err
		}
	}

	// Check Mewn is installed
	err := CheckMewn(projectOptions.Verbose)
	if err != nil {
		return err
	}

	compileMessage := "Packing + Compiling project"

	if buildMode == BuildModeDebug {
		compileMessage += " (Debug Mode)"
	}

	var packSpinner *spinner.Spinner
	if !projectOptions.Verbose {
		packSpinner = spinner.New(compileMessage + "...")
		packSpinner.SetSpinSpeed(50)
		packSpinner.Start()
	} else {
		println(compileMessage)
	}

	// embed resources
	targetFiles, err := EmbedAssets()
	if err != nil {
		return err
	}

	// cleanup temporary embedded assets
	defer func() {
		for _, filename := range targetFiles {
			if err := os.Remove(filename); err != nil {
				fmt.Println(err)
			}
		}
	}()

	buildCommand := slicer.String()
	buildCommand.Add("go")

	if buildMode == BuildModeBridge {
		// Ignore errors
		buildCommand.Add("-i")
	}

	buildCommand.Add("build")

	if binaryName != "" {
		// Alter binary name based on OS
		switch runtime.GOOS {
		case "windows":
			if !strings.HasSuffix(binaryName, ".exe") {
				binaryName += ".exe"
			}
		default:
			if strings.HasSuffix(binaryName, ".exe") {
				binaryName = strings.TrimSuffix(binaryName, ".exe")
			}
		}
		buildCommand.Add("-o", binaryName)
	}

	// If we are forcing a rebuild
	if forceRebuild {
		buildCommand.Add("-a")
	}

	// Setup ld flags
	ldflags := "-w -s "
	if buildMode == BuildModeDebug {
		ldflags = ""
	}

	// Add windows flags
	if runtime.GOOS == "windows" && buildMode == BuildModeProd {
		ldflags += "-H windowsgui "
	}

	ldflags += "-X github.com/wailsapp/wails.BuildMode=" + buildMode

	// If we wish to generate typescript
	if projectOptions.typescriptDefsFilename != "" {
		cwd, err := os.Getwd()
		if err != nil {
			return err
		}
		filename := filepath.Join(cwd, projectOptions.FrontEnd.Dir, projectOptions.typescriptDefsFilename)
		ldflags += " -X github.com/wailsapp/wails/lib/binding.typescriptDefinitionFilename=" + filename
	}

	buildCommand.AddSlice([]string{"-ldflags", ldflags})
	err = NewProgramHelper(projectOptions.Verbose).RunCommandArray(buildCommand.AsSlice())
	if err != nil {
		if packSpinner != nil {
			packSpinner.Error()
		}
		return err
	}
	if packSpinner != nil {
		packSpinner.Success()
	}

	// packageApp
	if packageApp {
		err = PackageApplication(projectOptions)
		if err != nil {
			return err
		}
	}

	return nil
}

// PackageApplication will attempt to package the application in a platform dependent way
func PackageApplication(projectOptions *ProjectOptions) error {
	// Package app
	message := "Generating .app"
	if runtime.GOOS == "windows" {
		err := CheckWindres()
		if err != nil {
			return err
		}
		message = "Generating resource bundle"
	}
	var packageSpinner *spinner.Spinner
	if projectOptions.Verbose {
		packageSpinner = spinner.New(message)
		packageSpinner.SetSpinSpeed(50)
		packageSpinner.Start()
	}
	err := NewPackageHelper().Package(projectOptions)
	if err != nil {
		if packageSpinner != nil {
			packageSpinner.Error()
		}
		return err
	}
	if packageSpinner != nil {
		packageSpinner.Success()
	}
	return nil
}

// BuildFrontend runs the given build command
func BuildFrontend(projectOptions *ProjectOptions) error {
	var buildFESpinner *spinner.Spinner
	if !projectOptions.Verbose {
		buildFESpinner = spinner.New("Building frontend...")
		buildFESpinner.SetSpinSpeed(50)
		buildFESpinner.Start()
	} else {
		println("Building frontend...")
	}
	err := NewProgramHelper(projectOptions.Verbose).RunCommand(projectOptions.FrontEnd.Build)
	if err != nil {
		if buildFESpinner != nil {
			buildFESpinner.Error()
		}
		return err
	}
	if buildFESpinner != nil {
		buildFESpinner.Success()
	}
	return nil
}

// CheckMewn checks if mewn is installed and if not, attempts to fetch it
func CheckMewn(verbose bool) (err error) {
	programHelper := NewProgramHelper(verbose)
	if !programHelper.IsInstalled("mewn") {
		var buildSpinner *spinner.Spinner
		if !verbose {
			buildSpinner = spinner.New()
			buildSpinner.SetSpinSpeed(50)
			buildSpinner.Start("Installing Mewn asset packer...")
		}
		err := programHelper.InstallGoPackage("github.com/leaanthony/mewn/cmd/mewn")
		if err != nil {
			if buildSpinner != nil {
				buildSpinner.Error()
			}
			return err
		}
		if buildSpinner != nil {
			buildSpinner.Success()
		}
	}
	return nil
}

// CheckWindres checks if Windres is installed and if not, aborts
func CheckWindres() (err error) {
	if runtime.GOOS != "windows" {
		return nil
	}
	programHelper := NewProgramHelper()
	if !programHelper.IsInstalled("windres") {
		return fmt.Errorf("windres not installed. It comes by default with mingw. Ensure you have installed mingw correctly")
	}
	return nil
}

// InstallFrontendDeps attempts to install the frontend dependencies based on the given options
func InstallFrontendDeps(projectDir string, projectOptions *ProjectOptions, forceRebuild bool, caller string) error {

	// Install frontend deps
	err := os.Chdir(projectOptions.FrontEnd.Dir)
	if err != nil {
		return err
	}

	// Check if frontend deps have been updated
	var feSpinner *spinner.Spinner
	if !projectOptions.Verbose {
		feSpinner = spinner.New("Ensuring frontend dependencies are up to date (This may take a while)")
		feSpinner.SetSpinSpeed(50)
		feSpinner.Start()
	} else {
		println("Ensuring frontend dependencies are up to date (This may take a while)")
	}

	requiresNPMInstall := true

	// Read in package.json MD5
	fs := NewFSHelper()
	packageJSONMD5, err := fs.FileMD5("package.json")
	if err != nil {
		return err
	}

	const md5sumFile = "package.json.md5"

	// If node_modules does not exist, force a rebuild.
	nodeModulesPath, err := filepath.Abs(filepath.Join(".", "node_modules"))
	if err != nil {
		return err
	}
	if !fs.DirExists(nodeModulesPath) {
		forceRebuild = true
	}

	// If we aren't forcing the install and the md5sum file exists
	if !forceRebuild && fs.FileExists(md5sumFile) {
		// Yes - read contents
		savedMD5sum, err := fs.LoadAsString(md5sumFile)
		// File exists
		if err == nil {
			// Compare md5
			if savedMD5sum == packageJSONMD5 {
				// Same - no need for reinstall
				requiresNPMInstall = false
				if feSpinner != nil {
					feSpinner.Success("Skipped frontend dependencies (-f to force rebuild)")
				} else {
					println("Skipped frontend dependencies (-f to force rebuild)")
				}
			}
		}
	}

	// Md5 sum package.json
	// Different? Build
	if requiresNPMInstall || forceRebuild {
		// Install dependencies
		err = NewProgramHelper(projectOptions.Verbose).RunCommand(projectOptions.FrontEnd.Install)
		if err != nil {
			if feSpinner != nil {
				feSpinner.Error()
			}
			return err
		}
		if feSpinner != nil {
			feSpinner.Success()
		}

		// Update md5sum file
		ioutil.WriteFile(md5sumFile, []byte(packageJSONMD5), 0644)
	}

	// Install the runtime
	err = InstallRuntime(caller, projectDir, projectOptions)
	if err != nil {
		return err
	}

	// Build frontend
	err = BuildFrontend(projectOptions)
	if err != nil {
		return err
	}
	return nil
}

// InstallRuntime installs the correct runtime for the type of build
func InstallRuntime(caller string, projectDir string, projectOptions *ProjectOptions) error {
	if caller == "build" {
		return InstallProdRuntime(projectDir, projectOptions)
	}

	return InstallBridge(projectDir, projectOptions)
}

// InstallBridge installs the relevant bridge javascript library
func InstallBridge(projectDir string, projectOptions *ProjectOptions) error {
	bridgeFileData := mewn.String("../runtime/assets/bridge.js")
	bridgeFileTarget := filepath.Join(projectDir, projectOptions.FrontEnd.Dir, "node_modules", "@wailsapp", "runtime", "init.js")
	err := fs.CreateFile(bridgeFileTarget, []byte(bridgeFileData))
	return err
}

// InstallProdRuntime installs the production runtime
func InstallProdRuntime(projectDir string, projectOptions *ProjectOptions) error {
	prodInit := mewn.String("../runtime/js/runtime/init.js")
	bridgeFileTarget := filepath.Join(projectDir, projectOptions.FrontEnd.Dir, "node_modules", "@wailsapp", "runtime", "init.js")
	err := fs.CreateFile(bridgeFileTarget, []byte(prodInit))
	return err
}

// ServeProject attempts to serve up the current project so that it may be connected to
// via the Wails bridge
func ServeProject(projectOptions *ProjectOptions, logger *Logger) error {
	go func() {
		time.Sleep(2 * time.Second)
		logger.Green(">>>>> To connect, you will need to run '" + projectOptions.FrontEnd.Serve + "' in the '" + projectOptions.FrontEnd.Dir + "' directory <<<<<")
	}()
	location, err := filepath.Abs(projectOptions.BinaryName)
	if err != nil {
		return err
	}

	logger.Yellow("Serving Application: " + location)
	cmd := exec.Command(location)
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	err = cmd.Run()
	if err != nil {
		return err
	}

	return nil
}