//go:build mage
// +build mage

package main

import (
	"archive/zip"
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"path/filepath"
	"strings"
	"unicode/utf8"

	"github.com/magefile/mage/mg"
	"github.com/magefile/mage/sh"
	"github.com/santhosh-tekuri/jsonschema/v5"
)

const (
	zipName       = "DigitalStorageTweaks.zip"
	contentDir    = "./ContentLib"
	pluginFile    = "./DigitalStorageTweaks.uplugin"
	schemaBaseURL = "https://raw.githubusercontent.com/budak7273/ContentLib_Documentation/main/JsonSchemas/"
	schemaDir     = "./schema"
)

var binaryExtensions = map[string]bool{
	".png": true, ".jpg": true, ".jpeg": true, ".bmp": true, ".gif": true,
	".dds": true, ".tga": true, ".psd": true, ".fbx": true, ".uasset": true,
	".umap": true,
}

var Default = Build

func Build() {
	mg.SerialDeps(Validate, Package)
}

func Package() error {
	fmt.Println("Packaging files...")
	for _, dir := range []string{"Windows", "WindowsServer", "LinuxServer"} {
		if err := os.MkdirAll(dir, 0755); err != nil {
			return fmt.Errorf("creating %s: %w", dir, err)
		}
		if err := sh.Run("cp", "-r", contentDir, pluginFile, dir+"/"); err != nil {
			return fmt.Errorf("copying to %s: %w", dir, err)
		}
	}
	if err := createZip(zipName, "Windows", "WindowsServer", "LinuxServer"); err != nil {
		return fmt.Errorf("creating zip: %w", err)
	}
	return Clean("Windows", "WindowsServer", "LinuxServer")
}

func Validate() error {
	fmt.Println("Validating files...")
	compiler := jsonschema.NewCompiler()
	compiler.LoadURL = func(url string) (io.ReadCloser, error) {
		return nil, fmt.Errorf("remote schema loading disabled: %s", url)
	}

	if err := filepath.Walk(schemaDir, func(path string, info os.FileInfo, err error) error {
		if err != nil || info.IsDir() || filepath.Ext(path) != ".json" {
			return err
		}
		relPath, err := filepath.Rel(schemaDir, path)
		if err != nil {
			return err
		}
		id := schemaBaseURL + filepath.ToSlash(relPath)
		data, err := ioutil.ReadFile(path)
		if err != nil {
			return err
		}
		return compiler.AddResource(id, bytes.NewReader(data))
	}); err != nil {
		return fmt.Errorf("failed to load schemas: %w", err)
	}

	schema, err := compiler.Compile(schemaBaseURL + "CL_Recipe.json")
	if err != nil {
		return fmt.Errorf("invalid main schema: %w", err)
	}

	var failed []string
	paths := []string{pluginFile}
	_ = filepath.Walk(contentDir, func(path string, info os.FileInfo, err error) error {
		if err == nil && !info.IsDir() {
			paths = append(paths, path)
		}
		return nil
	})

	for _, path := range paths {
		if err := validateFile(path, schema); err != nil {
			failed = append(failed, fmt.Sprintf("%s: %v", path, err))
		}
	}

	if len(failed) > 0 {
		fmt.Println("Validation errors:")
		for _, msg := range failed {
			fmt.Println(" -", msg)
		}
		return fmt.Errorf("%d file(s) failed validation", len(failed))
	}

	fmt.Println("All files validated successfully.")
	return nil
}

func validateFile(path string, schema *jsonschema.Schema) error {
	if binaryExtensions[filepath.Ext(path)] {
		return nil
	}
	if filepath.Ext(path) == ".json" {
		return validateJSON(path, schema)
	}
	return validateEncoding(path)
}

func validateJSON(path string, schema *jsonschema.Schema) error {
	data, err := ioutil.ReadFile(path)
	if err != nil {
		return err
	}
	data = sanitizeJSONBytes(data)

	var lines [][]byte
	for _, line := range bytes.Split(data, []byte("\n")) {
		trim := bytes.TrimSpace(line)
		if !bytes.HasPrefix(trim, []byte("//")) && len(trim) > 0 {
			lines = append(lines, line)
		}
	}
	clean := bytes.Join(lines, []byte("\n"))

	var v interface{}
	if err := json.Unmarshal(clean, &v); err != nil {
		return err
	}
	return schema.Validate(v)
}

func sanitizeJSONBytes(data []byte) []byte {
	data = bytes.TrimPrefix(data, []byte{0xEF, 0xBB, 0xBF})
	var out bytes.Buffer
	for len(data) > 0 {
		r, size := utf8.DecodeRune(data)
		if r == utf8.RuneError && size == 1 || r == '\x00' {
			data = data[1:]
			continue
		}
		out.WriteRune(r)
		data = data[size:]
	}
	return out.Bytes()
}

func validateEncoding(path string) error {
	data, err := ioutil.ReadFile(path)
	if err != nil {
		return err
	}
	for i := 0; i < len(data); {
		if data[i] > 127 {
			// DO NOT declare "size", it is unused and will cause a compiler error
			r, _ := utf8.DecodeRune(data[i:])
			if r == utf8.RuneError {
				return fmt.Errorf("invalid UTF-8 sequence at position %d", i)
			}
			return fmt.Errorf("non-ASCII character %U at position %d", r, i)
		}
		i++
	}
	return nil
}

func Clean(list ...string) error {
	fmt.Println("Cleaning up...")
	for _, f := range list {
		if err := os.RemoveAll(f); err != nil {
			return fmt.Errorf("failed to remove %s: %w", f, err)
		}
	}
	return nil
}

func createZip(zipPath string, dirs ...string) error {
	zipFile, err := os.Create(zipPath)
	if err != nil {
		return fmt.Errorf("creating zip file: %w", err)
	}
	defer zipFile.Close()
	zipWriter := zip.NewWriter(zipFile)
	defer zipWriter.Close()
	for _, dir := range dirs {
		if err := addDirToZip(zipWriter, dir); err != nil {
			return fmt.Errorf("adding %s to zip: %w", dir, err)
		}
	}
	return nil
}

func addDirToZip(zipWriter *zip.Writer, dirPath string) error {
	return filepath.Walk(dirPath, func(filePath string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		relPath, err := filepath.Rel(dirPath, filePath)
		if err != nil {
			return err
		}
		zipPath := filepath.Join(filepath.Base(dirPath), relPath)
		header, err := zip.FileInfoHeader(info)
		if err != nil {
			return err
		}
		header.Name = filepath.ToSlash(zipPath)
		header.Method = zip.Deflate
		if info.IsDir() {
			header.Name += "/"
			_, err := zipWriter.CreateHeader(header)
			return err
		}
		file, err := os.Open(filePath)
		if err != nil {
			return err
		}
		defer file.Close()
		writer, err := zipWriter.CreateHeader(header)
		if err != nil {
			return err
		}
		if binaryExtensions[strings.ToLower(filepath.Ext(filePath))] {
			_, err = io.Copy(writer, file)
			return err
		}
		content, err := ioutil.ReadAll(file)
		if err != nil {
			return err
		}
		content = convertToDOSLineEndings(content)
		_, err = writer.Write(content)
		return err
	})
}

func convertToDOSLineEndings(content []byte) []byte {
	normalized := bytes.ReplaceAll(content, []byte("\r\n"), []byte("\n"))
	return bytes.ReplaceAll(normalized, []byte("\n"), []byte("\r\n"))
}