package main

import (
	"bufio"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"reflect"
	"strconv"
	"strings"

	errors "github.com/pkg/errors"
	"gopkg.in/spf13/cobra.v0"

	yaml "gopkg.in/mikefarah/yaml.v2"
	logging "gopkg.in/op/go-logging.v1"
)

var trimOutput = true
var writeInplace = false
var writeScript = ""
var outputToJSON = false
var overwriteFlag = false
var verbose = false
var version = false
var docIndex = "0"
var log = logging.MustGetLogger("yq")

func main() {
	cmd := newCommandCLI()
	if err := cmd.Execute(); err != nil {
		log.Error(err.Error())
		os.Exit(1)
	}
}

func newCommandCLI() *cobra.Command {
	yaml.DefaultMapType = reflect.TypeOf(yaml.MapSlice{})
	var rootCmd = &cobra.Command{
		Use: "yq",
		RunE: func(cmd *cobra.Command, args []string) error {
			if version {
				cmd.Print(GetVersionDisplay())
				return nil
			}
			cmd.Println(cmd.UsageString())

			return nil
		},
		PersistentPreRun: func(cmd *cobra.Command, args []string) {
			var format = logging.MustStringFormatter(
				`%{color}%{time:15:04:05} %{shortfunc} [%{level:.4s}]%{color:reset} %{message}`,
			)
			var backend = logging.AddModuleLevel(
				logging.NewBackendFormatter(logging.NewLogBackend(os.Stderr, "", 0), format))

			if verbose {
				backend.SetLevel(logging.DEBUG, "")
			} else {
				backend.SetLevel(logging.ERROR, "")
			}

			logging.SetBackend(backend)
		},
	}

	rootCmd.PersistentFlags().BoolVarP(&trimOutput, "trim", "t", true, "trim yaml output")
	rootCmd.PersistentFlags().BoolVarP(&verbose, "verbose", "v", false, "verbose mode")
	rootCmd.Flags().BoolVarP(&version, "version", "V", false, "Print version information and quit")

	rootCmd.AddCommand(
		createReadCmd(),
		createWriteCmd(),
		createDeleteCmd(),
		createNewCmd(),
		createMergeCmd(),
	)
	rootCmd.SetOutput(os.Stdout)

	return rootCmd
}

func createReadCmd() *cobra.Command {
	var cmdRead = &cobra.Command{
		Use:     "read [yaml_file] [path]",
		Aliases: []string{"r"},
		Short:   "yq r [--doc/-d index] sample.yaml a.b.c",
		Example: `
yq read things.yaml a.b.c
yq r - a.b.c (reads from stdin)
yq r things.yaml a.*.c
yq r -d1 things.yaml a.array[0].blah
yq r things.yaml a.array[*].blah
      `,
		Long: "Outputs the value of the given path in the yaml file to STDOUT",
		RunE: readProperty,
	}
	cmdRead.PersistentFlags().StringVarP(&docIndex, "doc", "d", "0", "process document index number, 0 based")
	cmdRead.PersistentFlags().BoolVarP(&outputToJSON, "tojson", "j", false, "output as json")
	return cmdRead
}

func createWriteCmd() *cobra.Command {
	var cmdWrite = &cobra.Command{
		Use:     "write [yaml_file] [path] [value]",
		Aliases: []string{"w"},
		Short:   "yq w [--inplace/-i] [--script/-s script_file] [--doc/-d index] sample.yaml a.b.c newValue",
		Example: `
yq write things.yaml a.b.c cat
yq write --inplace things.yaml a.b.c cat
yq w -i things.yaml a.b.c cat
yq w --script update_script.yaml things.yaml
yq w -i -s update_script.yaml things.yaml
yq w --doc 2 things.yaml a.b.d[+] foo
yq w -d2 things.yaml a.b.d[+] foo
      `,
		Long: `Updates the yaml file w.r.t the given path and value.
Outputs to STDOUT unless the inplace flag is used, in which case the file is updated instead.

Append value to array adds the value to the end of array.

Update Scripts:
Note that you can give an update script to perform more sophisticated updated. Update script
format is a yaml map where the key is the path and the value is..well the value. e.g.:
---
a.b.c: true,
a.b.e:
  - name: bob
`,
		RunE: writeProperty,
	}
	cmdWrite.PersistentFlags().BoolVarP(&writeInplace, "inplace", "i", false, "update the yaml file inplace")
	cmdWrite.PersistentFlags().StringVarP(&writeScript, "script", "s", "", "yaml script for updating yaml")
	cmdWrite.PersistentFlags().StringVarP(&docIndex, "doc", "d", "0", "process document index number (0 based, * for all documents)")
	return cmdWrite
}

func createDeleteCmd() *cobra.Command {
	var cmdDelete = &cobra.Command{
		Use:     "delete [yaml_file] [path]",
		Aliases: []string{"d"},
		Short:   "yq d [--inplace/-i] [--doc/-d index] sample.yaml a.b.c",
		Example: `
yq delete things.yaml a.b.c
yq delete --inplace things.yaml a.b.c
yq d -i things.yaml a.b.c
yq d things.yaml a.b.c
	`,
		Long: `Deletes the given path from the YAML file.
Outputs to STDOUT unless the inplace flag is used, in which case the file is updated instead.
`,
		RunE: deleteProperty,
	}
	cmdDelete.PersistentFlags().BoolVarP(&writeInplace, "inplace", "i", false, "update the yaml file inplace")
	cmdDelete.PersistentFlags().StringVarP(&docIndex, "doc", "d", "0", "process document index number (0 based, * for all documents)")
	return cmdDelete
}

func createNewCmd() *cobra.Command {
	var cmdNew = &cobra.Command{
		Use:     "new [path] [value]",
		Aliases: []string{"n"},
		Short:   "yq n [--script/-s script_file] a.b.c newValue",
		Example: `
yq new a.b.c cat
yq n a.b.c cat
yq n --script create_script.yaml
      `,
		Long: `Creates a new yaml w.r.t the given path and value.
Outputs to STDOUT

Create Scripts:
Note that you can give a create script to perform more sophisticated yaml. This follows the same format as the update script.
`,
		RunE: newProperty,
	}
	cmdNew.PersistentFlags().StringVarP(&writeScript, "script", "s", "", "yaml script for updating yaml")
	return cmdNew
}

func createMergeCmd() *cobra.Command {
	var cmdMerge = &cobra.Command{
		Use:     "merge [initial_yaml_file] [additional_yaml_file]...",
		Aliases: []string{"m"},
		Short:   "yq m [--inplace/-i] [--doc/-d index] [--overwrite/-x] sample.yaml sample2.yaml",
		Example: `
yq merge things.yaml other.yaml
yq merge --inplace things.yaml other.yaml
yq m -i things.yaml other.yaml
yq m --overwrite things.yaml other.yaml
yq m -i -x things.yaml other.yaml
      `,
		Long: `Updates the yaml file by adding/updating the path(s) and value(s) from additional yaml file(s).
Outputs to STDOUT unless the inplace flag is used, in which case the file is updated instead.

If overwrite flag is set then existing values will be overwritten using the values from each additional yaml file.
`,
		RunE: mergeProperties,
	}
	cmdMerge.PersistentFlags().BoolVarP(&writeInplace, "inplace", "i", false, "update the yaml file inplace")
	cmdMerge.PersistentFlags().BoolVarP(&overwriteFlag, "overwrite", "x", false, "update the yaml file by overwriting existing values")
	cmdMerge.PersistentFlags().StringVarP(&docIndex, "doc", "d", "0", "process document index number (0 based, * for all documents)")
	return cmdMerge
}

func readProperty(cmd *cobra.Command, args []string) error {
	data, err := read(args)
	if err != nil {
		return err
	}
	dataStr, err := toString(data)
	if err != nil {
		return err
	}
	cmd.Println(dataStr)
	return nil
}

func read(args []string) (interface{}, error) {
	var path = ""

	if len(args) < 1 {
		return nil, errors.New("Must provide filename")
	} else if len(args) > 1 {
		path = args[1]
	}
	var generalData interface{}
	var docIndexInt, errorParsingDocumentIndex = strconv.ParseInt(docIndex, 10, 32)
	if errorParsingDocumentIndex != nil {
		return nil, errors.Wrapf(errorParsingDocumentIndex, "Document index %v is not a integer", docIndex)
	}
	if err := readData(args[0], int(docIndexInt), &generalData); err != nil {
		return nil, err
	}
	if path == "" {
		return generalData, nil
	}

	var paths = parsePath(path)
	return recurse(generalData, paths[0], paths[1:])
}

func newProperty(cmd *cobra.Command, args []string) error {
	updatedData, err := newYaml(args)
	if err != nil {
		return err
	}
	dataStr, err := toString(updatedData)
	if err != nil {
		return err
	}
	cmd.Println(dataStr)
	return nil
}

func newYaml(args []string) (interface{}, error) {
	var writeCommands, writeCommandsError = readWriteCommands(args, 2, "Must provide <path_to_update> <value>")
	if writeCommandsError != nil {
		return nil, writeCommandsError
	}

	var dataBucket interface{}
	var isArray = strings.HasPrefix(writeCommands[0].Key.(string), "[")
	if isArray {
		dataBucket = make([]interface{}, 0)
	} else {
		dataBucket = make(yaml.MapSlice, 0)
	}

	for _, entry := range writeCommands {
		path := entry.Key.(string)
		value := entry.Value
		log.Debugf("setting %v to %v", path, value)
		var paths = parsePath(path)
		dataBucket = updatedChildValue(dataBucket, paths, value)
	}

	return dataBucket, nil
}

func parseDocumentIndex() (bool, int, error) {
	if docIndex == "*" {
		return true, -1, nil
	}
	docIndexInt64, err := strconv.ParseInt(docIndex, 10, 32)
	if err != nil {
		return false, -1, errors.Wrapf(err, "Document index %v is not a integer or *", docIndex)
	}
	return false, int(docIndexInt64), nil
}

type updateDataFn func(dataBucket interface{}, currentIndex int) (interface{}, error)

func mapYamlDecoder(updateData updateDataFn, encoder *yaml.Encoder) yamlDecoderFn {
	return func(decoder *yaml.Decoder) error {
		var dataBucket interface{}
		var errorReading error
		var errorWriting error
		var errorUpdating error
		var currentIndex = 0

		var updateAll, docIndexInt, errorParsingDocIndex = parseDocumentIndex()
		if errorParsingDocIndex != nil {
			return errorParsingDocIndex
		}

		for {
			log.Debugf("Read doc %v", currentIndex)
			errorReading = decoder.Decode(&dataBucket)

			if errorReading == io.EOF {
				if !updateAll && currentIndex < docIndexInt {
					return fmt.Errorf("Asked to process document %v but there are only %v document(s)", docIndex, currentIndex)
				}
				return nil
			} else if errorReading != nil {
				return errors.Wrapf(errorReading, "Error reading document at index %v, %v", currentIndex, errorReading)
			}
			dataBucket, errorUpdating = updateData(dataBucket, currentIndex)
			if errorUpdating != nil {
				return errors.Wrapf(errorUpdating, "Error updating document at index %v", currentIndex)
			}

			errorWriting = encoder.Encode(dataBucket)

			if errorWriting != nil {
				return errors.Wrapf(errorWriting, "Error writing document at index %v, %v", currentIndex, errorWriting)
			}
			currentIndex = currentIndex + 1
		}
	}
}

func writeProperty(cmd *cobra.Command, args []string) error {
	var writeCommands, writeCommandsError = readWriteCommands(args, 3, "Must provide <filename> <path_to_update> <value>")
	if writeCommandsError != nil {
		return writeCommandsError
	}
	var updateAll, docIndexInt, errorParsingDocIndex = parseDocumentIndex()
	if errorParsingDocIndex != nil {
		return errorParsingDocIndex
	}

	var updateData = func(dataBucket interface{}, currentIndex int) (interface{}, error) {
		if updateAll || currentIndex == docIndexInt {
			log.Debugf("Updating doc %v", currentIndex)
			for _, entry := range writeCommands {
				path := entry.Key.(string)
				value := entry.Value
				log.Debugf("setting %v to %v", path, value)
				var paths = parsePath(path)
				dataBucket = updatedChildValue(dataBucket, paths, value)
			}
		}
		return dataBucket, nil
	}
	return readAndUpdate(cmd.OutOrStdout(), args[0], updateData)
}

func readAndUpdate(stdOut io.Writer, inputFile string, updateData updateDataFn) error {
	var destination io.Writer
	var destinationName string
	if writeInplace {
		var tempFile, err = ioutil.TempFile("", "temp")
		if err != nil {
			return err
		}
		destinationName = tempFile.Name()
		destination = tempFile
		defer func() {
			safelyCloseFile(tempFile)
			safelyRenameFile(tempFile.Name(), inputFile)
		}()
	} else {
		var writer = bufio.NewWriter(stdOut)
		destination = writer
		destinationName = "Stdout"
		defer safelyFlush(writer)
	}
	var encoder = yaml.NewEncoder(destination)
	log.Debugf("Writing to %v from %v", destinationName, inputFile)
	return readStream(inputFile, mapYamlDecoder(updateData, encoder))
}

func deleteProperty(cmd *cobra.Command, args []string) error {
	if len(args) < 2 {
		return errors.New("Must provide <filename> <path_to_delete>")
	}
	var deletePath = args[1]
	var paths = parsePath(deletePath)
	var updateAll, docIndexInt, errorParsingDocIndex = parseDocumentIndex()
	if errorParsingDocIndex != nil {
		return errorParsingDocIndex
	}

	var updateData = func(dataBucket interface{}, currentIndex int) (interface{}, error) {
		if updateAll || currentIndex == docIndexInt {
			log.Debugf("Deleting path in doc %v", currentIndex)
			return deleteChildValue(dataBucket, paths), nil
		}
		return dataBucket, nil
	}

	return readAndUpdate(cmd.OutOrStdout(), args[0], updateData)
}

func mergeProperties(cmd *cobra.Command, args []string) error {
	if len(args) < 2 {
		return errors.New("Must provide at least 2 yaml files")
	}
	var input = args[0]
	var filesToMerge = args[1:]
	var updateAll, docIndexInt, errorParsingDocIndex = parseDocumentIndex()
	if errorParsingDocIndex != nil {
		return errorParsingDocIndex
	}

	var updateData = func(dataBucket interface{}, currentIndex int) (interface{}, error) {
		if updateAll || currentIndex == docIndexInt {
			log.Debugf("Merging doc %v", currentIndex)
			var mergedData map[interface{}]interface{}
			if err := merge(&mergedData, dataBucket, overwriteFlag); err != nil {
				return nil, err
			}
			for _, f := range filesToMerge {
				var fileToMerge interface{}
				if err := readData(f, 0, &fileToMerge); err != nil {
					return nil, err
				}
				if err := merge(&mergedData, fileToMerge, overwriteFlag); err != nil {
					return nil, err
				}
			}
			return mergedData, nil
		}
		return dataBucket, nil
	}
	yaml.DefaultMapType = reflect.TypeOf(map[interface{}]interface{}{})
	defer func() { yaml.DefaultMapType = reflect.TypeOf(yaml.MapSlice{}) }()
	return readAndUpdate(cmd.OutOrStdout(), input, updateData)
}

func readWriteCommands(args []string, expectedArgs int, badArgsMessage string) (yaml.MapSlice, error) {
	var writeCommands yaml.MapSlice
	if writeScript != "" {
		if err := readData(writeScript, 0, &writeCommands); err != nil {
			return nil, err
		}
	} else if len(args) < expectedArgs {
		return nil, errors.New(badArgsMessage)
	} else {
		writeCommands = make(yaml.MapSlice, 1)
		writeCommands[0] = yaml.MapItem{Key: args[expectedArgs-2], Value: parseValue(args[expectedArgs-1])}
	}
	return writeCommands, nil
}

func parseValue(argument string) interface{} {
	var value, err interface{}
	var inQuotes = len(argument) > 0 && argument[0] == '"'
	if !inQuotes {
		value, err = strconv.ParseFloat(argument, 64)
		if err == nil {
			return value
		}
		value, err = strconv.ParseBool(argument)
		if err == nil {
			return value
		}
		if argument == "[]" {
			return make([]interface{}, 0)
		}
		return argument
	}
	return argument[1 : len(argument)-1]
}

func toString(context interface{}) (string, error) {
	if outputToJSON {
		return jsonToString(context)
	}
	return yamlToString(context)
}

func yamlToString(context interface{}) (string, error) {
	switch context.(type) {
	case string:
		return context.(string), nil
	default:
		return marshalContext(context)
	}
}

func marshalContext(context interface{}) (string, error) {
	out, err := yaml.Marshal(context)

	if err != nil {
		return "", errors.Wrap(err, "error printing yaml")
	}

	outStr := string(out)
	// trim the trailing new line as it's easier for a script to add
	// it in if required than to remove it
	if trimOutput {
		return strings.Trim(outStr, "\n "), nil
	}
	return outStr, nil
}

func safelyRenameFile(from string, to string) {
	if renameError := os.Rename(from, to); renameError != nil {
		log.Warningf("Error renaming from %v to %v, attemting to copy contents", from, to)
		log.Warning(renameError.Error())
		// can't do this rename when running in docker to a file targeted in a mounted volume,
		// so gracefully degrade to copying the entire contents.
		if copyError := copyFileContents(from, to); copyError != nil {
			log.Errorf("Failed copying from %v to %v", from, to)
			log.Errorf(copyError.Error())
		}
	}
}

// thanks https://stackoverflow.com/questions/21060945/simple-way-to-copy-a-file-in-golang
func copyFileContents(src, dst string) (err error) {
	in, err := os.Open(src)
	if err != nil {
		return err
	}
	defer safelyCloseFile(in)
	out, err := os.Create(dst)
	if err != nil {
		return err
	}
	defer safelyCloseFile(out)
	if _, err = io.Copy(out, in); err != nil {
		return err
	}
	return out.Sync()
}

func safelyFlush(writer *bufio.Writer) {
	if err := writer.Flush(); err != nil {
		log.Error("Error flushing writer!")
		log.Error(err.Error())
	}

}
func safelyCloseFile(file *os.File) {
	err := file.Close()
	if err != nil {
		log.Error("Error closing file!")
		log.Error(err.Error())
	}
}

type yamlDecoderFn func(*yaml.Decoder) error

func readStream(filename string, yamlDecoder yamlDecoderFn) error {
	if filename == "" {
		return errors.New("Must provide filename")
	}

	var stream io.Reader
	if filename == "-" {
		stream = bufio.NewReader(os.Stdin)
	} else {
		file, err := os.Open(filename)
		if err != nil {
			return err
		}
		defer safelyCloseFile(file)
		stream = file
	}
	return yamlDecoder(yaml.NewDecoder(stream))
}

func readData(filename string, indexToRead int, parsedData interface{}) error {
	return readStream(filename, func(decoder *yaml.Decoder) error {
		for currentIndex := 0; currentIndex < indexToRead; currentIndex++ {
			errorSkipping := decoder.Decode(parsedData)
			if errorSkipping != nil {
				return errors.Wrapf(errorSkipping, "Error processing document at index %v, %v", currentIndex, errorSkipping)
			}
		}
		return decoder.Decode(parsedData)
	})
}