package main

import (
	"errors"
	"fmt"
	"io/ioutil"
	"os"
	"strconv"
	"strings"

	logging "github.com/op/go-logging"
	"github.com/spf13/cobra"
	yaml "gopkg.in/yaml.v2"
)

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

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

func newCommandCLI() *cobra.Command {
	var rootCmd = &cobra.Command{
		Use: "yaml",
		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(&outputToJSON, "tojson", "j", false, "output as json")
	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(), createNewCmd(), createMergeCmd())
	rootCmd.SetOutput(os.Stdout)

	return rootCmd
}

func createReadCmd() *cobra.Command {
	return &cobra.Command{
		Use:     "read [yaml_file] [path]",
		Aliases: []string{"r"},
		Short:   "yaml r sample.yaml a.b.c",
		Example: `
yaml read things.yaml a.b.c
yaml r - a.b.c (reads from stdin)
yaml r things.yaml a.*.c
yaml r things.yaml a.array[0].blah
yaml r things.yaml a.array[*].blah
      `,
		Long: "Outputs the value of the given path in the yaml file to STDOUT",
		RunE: readProperty,
	}
}

func createWriteCmd() *cobra.Command {
	var cmdWrite = &cobra.Command{
		Use:     "write [yaml_file] [path] [value]",
		Aliases: []string{"w"},
		Short:   "yaml w [--inplace/-i] [--script/-s script_file] sample.yaml a.b.c newValueForC",
		Example: `
yaml write things.yaml a.b.c cat
yaml write --inplace things.yaml a.b.c cat
yaml w -i things.yaml a.b.c cat
yaml w --script update_script.yaml things.yaml
yaml w -i -s update_script.yaml things.yaml
yaml w things.yaml a.b.d[+] foo
yaml w 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")
	return cmdWrite
}

func createNewCmd() *cobra.Command {
	var cmdNew = &cobra.Command{
		Use:     "new [path] [value]",
		Aliases: []string{"n"},
		Short:   "yaml n [--script/-s script_file] a.b.c newValueForC",
		Example: `
yaml new a.b.c cat
yaml n a.b.c cat
yaml 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:   "yaml m [--inplace/-i] [--overwrite/-x] sample.yaml sample2.yaml",
		Example: `
yaml merge things.yaml other.yaml
yaml merge --inplace things.yaml other.yaml
yaml m -i things.yaml other.yaml
yaml m --overwrite things.yaml other.yaml
yaml 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")
	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 parsedData yaml.MapSlice
	var path = ""

	if len(args) < 1 {
		return nil, errors.New("Must provide filename")
	} else if len(args) > 1 {
		path = args[1]
	}

	if err := readData(args[0], &parsedData); err != nil {
		var generalData interface{}
		if err = readData(args[0], &generalData); err != nil {
			return nil, err
		}
		item := yaml.MapItem{Key: "thing", Value: generalData}
		parsedData = yaml.MapSlice{item}
		path = "thing." + path
	}

	if parsedData != nil && parsedData[0].Key == nil {
		var interfaceData []map[interface{}]interface{}
		if err := readData(args[0], &interfaceData); err == nil {
			var listMap []yaml.MapSlice
			for _, item := range interfaceData {
				listMap = append(listMap, mapToMapSlice(item))
			}
			return readYamlArray(listMap, path)
		}
	}

	if path == "" {
		return parsedData, nil
	}

	var paths = parsePath(path)

	return readMap(parsedData, paths[0], paths[1:])
}

func readYamlArray(listMap []yaml.MapSlice, path string) (interface{}, error) {
	if path == "" {
		return listMap, nil
	}

	var paths = parsePath(path)

	if paths[0] == "*" {
		if len(paths[1:]) == 0 {
			return listMap, nil
		}
		var results []interface{}
		for _, m := range listMap {
			value, err := readMap(m, paths[1], paths[2:])
			if err != nil {
				return nil, err
			}
			results = append(results, value)
		}
		return results, nil
	}

	index, err := strconv.ParseInt(paths[0], 10, 64)
	if err != nil {
		return nil, fmt.Errorf("Error accessing array: %v", err)
	}
	if len(paths[1:]) == 0 {
		return listMap[index], nil
	}
	return readMap(listMap[index], paths[1], paths[2:])
}

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 yaml.MapSlice
	if writeScript != "" {
		if err := readData(writeScript, &writeCommands); err != nil {
			return nil, err
		}
	} else if len(args) < 2 {
		return nil, errors.New("Must provide <path_to_update> <value>")
	} else {
		writeCommands = make(yaml.MapSlice, 1)
		writeCommands[0] = yaml.MapItem{Key: args[0], Value: parseValue(args[1])}
	}

	var parsedData yaml.MapSlice
	var prependCommand = ""
	var isArray = strings.HasPrefix(writeCommands[0].Key.(string), "[")
	if isArray {
		item := yaml.MapItem{Key: "thing", Value: make(yaml.MapSlice, 0)}
		parsedData = yaml.MapSlice{item}
		prependCommand = "thing"
	} else {
		parsedData = make(yaml.MapSlice, 0)
	}

	return updateParsedData(parsedData, writeCommands, prependCommand)
}

func writeProperty(cmd *cobra.Command, args []string) error {
	updatedData, err := updateYaml(args)
	if err != nil {
		return err
	}
	return write(cmd, args[0], updatedData)
}

func write(cmd *cobra.Command, filename string, updatedData interface{}) error {
	if writeInplace {
		dataStr, err := yamlToString(updatedData)
		if err != nil {
			return err
		}
		return ioutil.WriteFile(filename, []byte(dataStr), 0644)
	}
	dataStr, err := toString(updatedData)
	if err != nil {
		return err
	}
	cmd.Println(dataStr)
	return nil
}

func mergeProperties(cmd *cobra.Command, args []string) error {
	if len(args) < 2 {
		return errors.New("Must provide at least 2 yaml files")
	}

	updatedData, err := mergeYaml(args)
	if err != nil {
		return err
	}
	return write(cmd, args[0], updatedData)
}

func mergeYaml(args []string) (interface{}, error) {
	var updatedData map[interface{}]interface{}

	for _, f := range args {
		var parsedData map[interface{}]interface{}
		if err := readData(f, &parsedData); err != nil {
			return nil, err
		}
		if err := merge(&updatedData, parsedData, overwriteFlag); err != nil {
			return nil, err
		}
	}

	return mapToMapSlice(updatedData), nil
}

func updateParsedData(parsedData yaml.MapSlice, writeCommands yaml.MapSlice, prependCommand string) (interface{}, error) {
	var prefix = ""
	if prependCommand != "" {
		prefix = prependCommand + "."
	}
	for _, entry := range writeCommands {
		path := prefix + entry.Key.(string)
		value := entry.Value
		var paths = parsePath(path)
		parsedData = writeMap(parsedData, paths, value)
	}
	if prependCommand != "" {
		return readMap(parsedData, prependCommand, make([]string, 0))
	}
	return parsedData, nil
}

func updateYaml(args []string) (interface{}, error) {
	var writeCommands yaml.MapSlice
	var prependCommand = ""
	if writeScript != "" {
		if err := readData(writeScript, &writeCommands); err != nil {
			return nil, err
		}
	} else if len(args) < 3 {
		return nil, errors.New("Must provide <filename> <path_to_update> <value>")
	} else {
		writeCommands = make(yaml.MapSlice, 1)
		writeCommands[0] = yaml.MapItem{Key: args[1], Value: parseValue(args[2])}
	}

	var parsedData yaml.MapSlice
	if err := readData(args[0], &parsedData); err != nil {
		var generalData interface{}
		if err = readData(args[0], &generalData); err != nil {
			return nil, err
		}
		item := yaml.MapItem{Key: "thing", Value: generalData}
		parsedData = yaml.MapSlice{item}
		prependCommand = "thing"
	}

	return updateParsedData(parsedData, writeCommands, prependCommand)
}

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) {
	out, err := yaml.Marshal(context)
	if err != nil {
		return "", fmt.Errorf("error printing yaml: %v", err)
	}
	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 readData(filename string, parsedData interface{}) error {
	if filename == "" {
		return errors.New("Must provide filename")
	}

	var rawData []byte
	var err error
	if filename == "-" {
		rawData, err = ioutil.ReadAll(os.Stdin)
	} else {
		rawData, err = ioutil.ReadFile(filename)
	}

	if err != nil {
		return err
	}

	return yaml.Unmarshal(rawData, parsedData)
}