package common

import (
	"crypto/ed25519"
	"crypto/x509"
	"encoding/pem"
	"errors"
	"eternity/lib"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"github.com/fatih/color"
)

var DefaultLogger = lib.Logger{
	LogFunc: func(log lib.Log) string {
		var severityPretty string
		switch log.Level {
		case "INFO":
			severityPretty = color.GreenString("[INFO]")
		case "WARN":
			severityPretty = color.YellowString("[WARN]")
		case "ERROR":
			severityPretty = color.HiYellowString("[ERROR]")
		case "CRITICAL":
			severityPretty = color.HiRedString("[CRITICAL]")
		case "FATAL":
			fmt.Println(color.RedString("[FATAL]"), log.Content)
			os.Exit(1)
		default:
			severityPretty = color.WhiteString("[" + strings.ToUpper(log.Level) + "]")
		}
		fmt.Println(severityPretty, log.Content)
		if log.Prompt {
			fmt.Print(": ")
			var userInput string
			_, err := fmt.Scanln(&userInput)
			if err != nil {
				fmt.Println(color.RedString("[FATAL]"), "Failed to read user input:", err)
				os.Exit(1)
			} else {
				return userInput
			}
		}
		return ""
	},
	PromptSupported: true,
}

// EternityJsonHandleError handles errors related to the parsing of eternity.json
func EternityJsonHandleError(err error, vagueError error, logger *lib.Logger) {
	switch {
	case errors.Is(vagueError, lib.ErrEternityJsonOpenError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to open eternity.json: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, lib.ErrEternityJsonReadError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to reading eternity.json: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, lib.ErrEternityJsonParseError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to parse eternity.json: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, lib.ErrEternityJsonMapError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to map eternity.json: " + err.Error(),
			Prompt:  false,
		})
	}
}

// BuildEPKRemoveTemporaryDirectory removes the temporary directory created by BuildEPK
func BuildEPKRemoveTemporaryDirectory(tempDir string, logger *lib.Logger) {
	err := os.RemoveAll(tempDir)
	if err != nil {
		logger.LogFunc(lib.Log{
			Level:   "ERROR",
			Content: "Failed to cleanup temporary directory: " + err.Error(),
			Prompt:  false,
		})
	}
}

// BuildEPKHandleError handles errors related to the building of EPKs
func BuildEPKHandleError(tempDir string, err error, vagueError error, logger *lib.Logger) {
	switch {
	case errors.Is(vagueError, lib.ErrBuildEPKChrootError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Chroot containers are not yet supported",
			Prompt:  false,
		})
	case errors.Is(vagueError, lib.ErrBuildEPKUnrestrictedError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Unrestricted builds are not yet supported",
			Prompt:  false,
		})
	case errors.Is(vagueError, lib.ErrBuildEPKTemporaryDirectoryError):
		BuildEPKRemoveTemporaryDirectory(tempDir, logger)
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to create temporary directory: " + err.Error(),
		})
	case errors.Is(vagueError, lib.ErrBuildEPKCreateHooksError):
		BuildEPKRemoveTemporaryDirectory(tempDir, logger)
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to create hooks directory: " + err.Error(),
		})
	case errors.Is(vagueError, lib.ErrBuildEPKCopyHooksError):
		BuildEPKRemoveTemporaryDirectory(tempDir, logger)
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to copy hooks: " + err.Error(),
		})
	case errors.Is(vagueError, lib.ErrBuildEPKBuildShError):
		BuildEPKRemoveTemporaryDirectory(tempDir, logger)
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to create build.sh: " + err.Error(),
		})
	case errors.Is(vagueError, lib.ErrBuildEPKWritingBuildShError):
		BuildEPKRemoveTemporaryDirectory(tempDir, logger)
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to write to build.sh: " + err.Error(),
		})
	case errors.Is(vagueError, lib.ErrBuildEPKTargetRootError):
		BuildEPKRemoveTemporaryDirectory(tempDir, logger)
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to create target root: " + err.Error(),
		})
	case errors.Is(vagueError, lib.ErrBuildEPKExecutingBuildShError):
		BuildEPKRemoveTemporaryDirectory(tempDir, logger)
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to start BubbleWrap container and run build.sh in it: " + err.Error(),
		})
	case errors.Is(vagueError, lib.ErrBuildEPKCountingFilesError):
		BuildEPKRemoveTemporaryDirectory(tempDir, logger)
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to count files in target root: " + err.Error(),
		})
	}
}

// These errors are in the wrong order due to this function being rewritten.
// Oh well, not like it matters.

// PackageEPKHandleError handles errors related to the packaging of EPKs
func PackageEPKHandleError(err error, vagueError error, logger *lib.Logger) {
	switch {
	case errors.Is(vagueError, lib.ErrPackageEPKCreateDistDirError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to create dist directory: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, lib.ErrPackageEPKMoveToDistError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to move to dist directory: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, lib.ErrPackageEPKTarError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to create Tar archive: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, lib.ErrPackageEPKJSONMarshal):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to marshal JSON: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, lib.ErrPackageEPKCreateCompressionWriterError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to create compression writer: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, lib.ErrPackageEPKCompressCloseError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to close compression writer: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, lib.ErrPackageEPKCannotOpenFile):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to open file for writing: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, lib.ErrPackageEPKCannotWriteFile):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to write to file: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, lib.ErrPackageEPKCannotCloseFile):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to close file: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, lib.ErrPackageEPKFailedToSeek):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to move file cursor: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, lib.ErrPackageEPKFailedToWriteHash):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to generate hash: " + err.Error(),
			Prompt:  false,
		})
	}
}

var LoadPrivateKeyHomedirError = errors.New("failed to get home directory")
var LoadPrivateKeyReadError = errors.New("failed to read private key")
var LoadPrivateKeyGenerateError = errors.New("failed to generate private key")
var LoadPrivateKeyMarshalError = errors.New("failed to marshal private key")
var LoadPrivateKeyFolderCreateError = errors.New("failed to create folder")
var LoadPrivateKeyWriteError = errors.New("failed to write private key")
var LoadPrivateKeyEmptyBlockError = errors.New("blocks returned by pem.Decode are empty")
var LoadPrivateKeyParseError = errors.New("failed to parse private key")
var LoadPrivateKeyNotEd25519Error = errors.New("private key is not ed25519")

// LoadPrivateKey loads the private key from $HOME/.local/share/eternity/private.key
func LoadPrivateKey(logger *lib.Logger) (ed25519.PrivateKey, error, error) {
	// Attempt to read the key from $HOME/.local/share/eternity/private.key
	homeDir, err := os.UserHomeDir()
	if err != nil {
		return nil, err, LoadPrivateKeyHomedirError
	}

	privateKeyBytes, err := os.ReadFile(filepath.Join(homeDir, ".local/share/eternity/private.key"))
	if err != nil {
		if !os.IsNotExist(err) {
			return nil, err, LoadPrivateKeyReadError
		} else {
			response := logger.LogFunc(lib.Log{
				Level:   "INFO",
				Content: "You need to add a private key to sign EPKs. Would you like to generate one now? (y/n)",
				Prompt:  true,
			})
			if strings.ToLower(response) == "y" {
				_, privateKey, err := ed25519.GenerateKey(nil)
				if err != nil {
					return nil, err, LoadPrivateKeyGenerateError
				}

				privateKeyBytes, err := x509.MarshalPKCS8PrivateKey(privateKey)
				if err != nil {
					return nil, err, LoadPrivateKeyMarshalError
				}

				privateKeyFile := pem.EncodeToMemory(&pem.Block{
					Type:  "ED25519 PRIVATE KEY",
					Bytes: privateKeyBytes,
				})

				err = os.MkdirAll(filepath.Join(homeDir, ".local/share/eternity"), 0700)
				if err != nil {
					return nil, err, LoadPrivateKeyFolderCreateError
				}

				err = os.WriteFile(filepath.Join(homeDir, ".local/share/eternity/private.key"), privateKeyFile, 0600)
				if err != nil {
					return nil, err, LoadPrivateKeyWriteError
				}

				logger.LogFunc(lib.Log{
					Level:   "INFO",
					Content: "Private key written to disk",
					Prompt:  false,
				})

				return privateKey, nil, nil
			} else if strings.ToLower(response) == "n" {
				logger.LogFunc(lib.Log{
					Level:   "INFO",
					Content: "Understood. Please add a ed25519 private key to " + filepath.Join(homeDir, ".local/share/eternity/private.key") + " in order to sign EPKs and repositories",
					Prompt:  false,
				})

				os.Exit(1)
			}
		}
	}

	block, _ := pem.Decode(privateKeyBytes)
	if block == nil {
		return nil, nil, LoadPrivateKeyEmptyBlockError
	}

	privateKey, err := x509.ParsePKCS8PrivateKey(block.Bytes)
	if err != nil {
		return nil, err, LoadPrivateKeyParseError
	}

	ed25519PrivateKey, ok := privateKey.(ed25519.PrivateKey)
	if !ok {
		return nil, nil, LoadPrivateKeyNotEd25519Error
	}

	return ed25519PrivateKey, nil, nil
}

// LoadPrivateKeyHandleError handles errors related to LoadPrivateKey
func LoadPrivateKeyHandleError(err error, vagueError error, logger *lib.Logger) {
	switch {
	case errors.Is(vagueError, LoadPrivateKeyHomedirError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to get home directory: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, LoadPrivateKeyReadError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to read private key: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, LoadPrivateKeyGenerateError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to generate private key: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, LoadPrivateKeyMarshalError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to marshal private key: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, LoadPrivateKeyFolderCreateError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to create eternity config folder (are you missing permissions?): " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, LoadPrivateKeyWriteError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to write private key to disk: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, LoadPrivateKeyEmptyBlockError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Blocks returned by pem.Decode are empty",
			Prompt:  false,
		})
	case errors.Is(vagueError, LoadPrivateKeyParseError):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Failed to parse private key: " + err.Error(),
			Prompt:  false,
		})
	case errors.Is(vagueError, LoadPrivateKeyNotEd25519Error):
		logger.LogFunc(lib.Log{
			Level:   "FATAL",
			Content: "Private key is not a ed25519 key",
			Prompt:  false,
		})
	}
}