/*
Copyright (c) 2014-2024 VMware, Inc. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package flags

import (
	"context"
	"encoding/json"
	"errors"
	"flag"
	"fmt"
	"io"
	"os"
	"reflect"
	"strings"
	"time"

	"github.com/dougm/pretty"

	"github.com/vmware/govmomi/govc/cli"
	"github.com/vmware/govmomi/task"
	"github.com/vmware/govmomi/vim25/progress"
	"github.com/vmware/govmomi/vim25/soap"
	"github.com/vmware/govmomi/vim25/types"
	"github.com/vmware/govmomi/vim25/xml"
)

type OutputWriter interface {
	Write(io.Writer) error
}

type OutputFlag struct {
	common

	JSON bool
	XML  bool
	TTY  bool
	Dump bool
	Out  io.Writer
	Spec bool

	formatError  bool
	formatIndent bool
}

var outputFlagKey = flagKey("output")

func NewOutputFlag(ctx context.Context) (*OutputFlag, context.Context) {
	if v := ctx.Value(outputFlagKey); v != nil {
		return v.(*OutputFlag), ctx
	}

	v := &OutputFlag{Out: os.Stdout}
	ctx = context.WithValue(ctx, outputFlagKey, v)
	return v, ctx
}

func (flag *OutputFlag) Register(ctx context.Context, f *flag.FlagSet) {
	flag.RegisterOnce(func() {
		f.BoolVar(&flag.JSON, "json", false, "Enable JSON output")
		f.BoolVar(&flag.XML, "xml", false, "Enable XML output")
		f.BoolVar(&flag.Dump, "dump", false, "Enable Go output")
		if cli.ShowUnreleased() {
			f.BoolVar(&flag.Spec, "spec", false, "Output spec without sending request")
		}
		// Avoid adding more flags for now..
		flag.formatIndent = os.Getenv("GOVC_INDENT") != "false"      // Default to indented output
		flag.formatError = os.Getenv("GOVC_FORMAT_ERROR") != "false" // Default to formatted errors
	})
}

func (flag *OutputFlag) Process(ctx context.Context) error {
	return flag.ProcessOnce(func() error {
		if !flag.All() {
			// Assume we have a tty if not outputting JSON
			flag.TTY = true
		}

		return nil
	})
}

// Log outputs the specified string, prefixed with the current time.
// A newline is not automatically added. If the specified string
// starts with a '\r', the current line is cleared first.
func (flag *OutputFlag) Log(s string) (int, error) {
	if len(s) > 0 && s[0] == '\r' {
		flag.Write([]byte{'\r', 033, '[', 'K'})
		s = s[1:]
	}

	return flag.WriteString(time.Now().Format("[02-01-06 15:04:05] ") + s)
}

func (flag *OutputFlag) Write(b []byte) (int, error) {
	if !flag.TTY {
		return 0, nil
	}

	w := flag.Out
	if w == nil {
		w = os.Stdout
	}
	n, err := w.Write(b)
	if w == os.Stdout {
		os.Stdout.Sync()
	}
	return n, err
}

func (flag *OutputFlag) WriteString(s string) (int, error) {
	return flag.Write([]byte(s))
}

func (flag *OutputFlag) All() bool {
	return flag.JSON || flag.XML || flag.Dump
}

func dumpValue(val interface{}) interface{} {
	type dumper interface {
		Dump() interface{}
	}

	if d, ok := val.(dumper); ok {
		return d.Dump()
	}

	rval := reflect.ValueOf(val)
	if rval.Type().Kind() != reflect.Ptr {
		return val
	}

	rval = rval.Elem()
	if rval.Type().Kind() == reflect.Struct {
		f := rval.Field(0)
		if f.Type().Kind() == reflect.Slice {
			// common case for the various 'type infoResult'
			if f.Len() == 1 {
				return f.Index(0).Interface()
			}
			return f.Interface()
		}

		if rval.NumField() == 1 && rval.Type().Field(0).Anonymous {
			// common case where govc type wraps govmomi type to implement OutputWriter
			return f.Interface()
		}
	}

	return val
}

type outputAny struct {
	Value any
}

func (*outputAny) Write(io.Writer) error {
	return nil
}

func (a *outputAny) Dump() interface{} {
	return a.Value
}

func (flag *OutputFlag) WriteAny(val any) error {
	if !flag.All() {
		flag.XML = true
	}
	return flag.WriteResult(&outputAny{val})
}

func (flag *OutputFlag) WriteResult(result OutputWriter) error {
	var err error

	switch {
	case flag.Dump:
		format := "%#v\n"
		if flag.formatIndent {
			format = "%# v\n"
		}
		_, err = pretty.Fprintf(flag.Out, format, dumpValue(result))
	case flag.JSON:
		e := json.NewEncoder(flag.Out)
		if flag.formatIndent {
			e.SetIndent("", "  ")
		}
		err = e.Encode(result)
	case flag.XML:
		e := xml.NewEncoder(flag.Out)
		if flag.formatIndent {
			e.Indent("", "  ")
		}
		err = e.Encode(dumpValue(result))
		if err == nil {
			fmt.Fprintln(flag.Out)
		}
	default:
		err = result.Write(flag.Out)
	}

	return err
}

func (flag *OutputFlag) WriteError(err error) bool {
	if flag.formatError {
		flag.Out = os.Stderr
		return flag.WriteResult(&errorOutput{err}) == nil
	}
	return false
}

type errorOutput struct {
	error
}

func (e errorOutput) Write(w io.Writer) error {
	reason := e.Error()
	var messages []string
	var faults []types.LocalizableMessage

	switch err := e.error.(type) {
	case task.Error:
		faults = err.LocalizedMethodFault.Fault.GetMethodFault().FaultMessage
		if err.Description != nil {
			reason = fmt.Sprintf("%s (%s)", reason, err.Description.Message)
		}
	default:
		if soap.IsSoapFault(err) {
			detail := soap.ToSoapFault(err).Detail.Fault
			if f, ok := detail.(types.BaseMethodFault); ok {
				faults = f.GetMethodFault().FaultMessage
			}
		}
	}

	for _, m := range faults {
		if m.Message != "" && !strings.HasPrefix(m.Message, "[context]") {
			messages = append(messages, fmt.Sprintf("%s (%s)", m.Message, m.Key))
		}
	}

	messages = append(messages, reason)

	for _, message := range messages {
		if _, err := fmt.Fprintf(w, "%s: %s\n", os.Args[0], message); err != nil {
			return err
		}
	}

	return nil
}

func (e errorOutput) Dump() interface{} {
	if f, ok := e.error.(task.Error); ok {
		return f.LocalizedMethodFault
	}
	if soap.IsSoapFault(e.error) {
		return soap.ToSoapFault(e.error)
	}
	if soap.IsVimFault(e.error) {
		return soap.ToVimFault(e.error)
	}
	return e
}

func (e errorOutput) canEncode() bool {
	switch e.error.(type) {
	case task.Error:
		return true
	}
	return soap.IsSoapFault(e.error) || soap.IsVimFault(e.error)
}

// errCannotEncode causes cli.Run to output err.Error() as it would without an error format specified
var errCannotEncode = errors.New("cannot encode error")

func (e errorOutput) MarshalJSON() ([]byte, error) {
	_, ok := e.error.(json.Marshaler)
	if ok || e.canEncode() {
		return json.Marshal(e.error)
	}
	return nil, errCannotEncode
}

func (e errorOutput) MarshalXML(encoder *xml.Encoder, start xml.StartElement) error {
	_, ok := e.error.(xml.Marshaler)
	if ok || e.canEncode() {
		return encoder.Encode(e.error)
	}
	return errCannotEncode
}

func (flag *OutputFlag) ProgressLogger(prefix string) *progress.ProgressLogger {
	return progress.NewProgressLogger(flag.Log, prefix)
}