// Copyright 2013-2023 The Cobra Authors
//
// 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 cobra

import (
	"fmt"
	"os"
	"sort"
	"strconv"
	"strings"

	"github.com/ghetzel/go-stockutil/sliceutil"
	flag "github.com/spf13/pflag"
)

const (
	requiredAsGroup                         = "cobra_annotation_required_if_others_set"
	oneRequired                             = "cobra_annotation_one_required"
	mutuallyExclusive                       = "cobra_annotation_mutually_exclusive"
	_ANNOTATION_PREREQUISITE                = "cobra_annotation_prerequisite"
	_ANNOTATION_DEPENDANT                   = "cobra_annotation_dependant"
	_ANNOTATION_PREREQUISITE_MISSING_ACTION = "cobra_annotation_prerequisite_missing_action"
)

// MarkFlagsRequiredTogether marks the given flags with annotations so that Cobra errors
// if the command is invoked with a subset (but not all) of the given flags.
func (c *Command) MarkFlagsRequiredTogether(flagNames ...string) {
	c.mergePersistentFlags()
	for _, v := range flagNames {
		f := c.Flags().Lookup(v)
		if f == nil {
			panic(fmt.Sprintf("Failed to find flag %q and mark it as being required in a flag group", v))
		}
		if err := c.Flags().SetAnnotation(v, requiredAsGroup, append(f.Annotations[requiredAsGroup], strings.Join(flagNames, " "))); err != nil {
			// Only errs if the flag isn't found.
			panic(err)
		}
	}
}

// MarkFlagsOneRequired marks the given flags with annotations so that Cobra errors
// if the command is invoked without at least one flag from the given set of flags.
func (c *Command) MarkFlagsOneRequired(flagNames ...string) {
	c.mergePersistentFlags()
	for _, v := range flagNames {
		f := c.Flags().Lookup(v)
		if f == nil {
			panic(fmt.Sprintf("Failed to find flag %q and mark it as being in a one-required flag group", v))
		}
		if err := c.Flags().SetAnnotation(v, oneRequired, append(f.Annotations[oneRequired], strings.Join(flagNames, " "))); err != nil {
			// Only errs if the flag isn't found.
			panic(err)
		}
	}
}

// MarkFlagsMutuallyExclusive marks the given flags with annotations so that Cobra errors
// if the command is invoked with more than one flag from the given set of flags.
func (c *Command) MarkFlagsMutuallyExclusive(flagNames ...string) {
	c.mergePersistentFlags()
	for _, v := range flagNames {
		f := c.Flags().Lookup(v)
		if f == nil {
			panic(fmt.Sprintf("Failed to find flag %q and mark it as being in a mutually exclusive flag group", v))
		}
		// Each time this is called is a single new entry; this allows it to be a member of multiple groups if needed.
		if err := c.Flags().SetAnnotation(v, mutuallyExclusive, append(f.Annotations[mutuallyExclusive], strings.Join(flagNames, " "))); err != nil {
			panic(err)
		}
	}
}

const (
	PREREQUISITE_MISSING_IGNORE = 0
	PREREQUISITE_MISSING_PANIC  = 1
	PREREQUISITE_MISSING_MURMUR = 2
)

func (c *Command) MarkFlagsPrerequisite(prerequisites, dependants []string, l int) {
	if len(prerequisites) <= 0 || len(dependants) <= 0 {
		panic("Prerequisite or dependant flags cannot be empty")
	}
	var invalidPrerequisites []interface{} = sliceutil.Intersect(prerequisites, dependants)
	if len(invalidPrerequisites) > 0 {
		panic(fmt.Sprintf("Flags %v cannot be prerequisite of themselves", invalidPrerequisites))
	}
	c.mergePersistentFlags()
	for _, flagNameDep := range dependants { // check dependant flags
		fDep := c.Flags().Lookup(flagNameDep)
		if fDep == nil {
			panic(fmt.Sprintf("Failed to find flag %q and mark its prerequisites", flagNameDep))
		}
		if _, ok := fDep.Annotations[_ANNOTATION_PREREQUISITE]; !ok {
			fDep.Annotations = map[string][]string{}
		}
		fDep.Annotations[_ANNOTATION_PREREQUISITE] = append(fDep.Annotations[_ANNOTATION_PREREQUISITE], prerequisites...)
		if errAnno := c.Flags().SetAnnotation(flagNameDep, _ANNOTATION_PREREQUISITE_MISSING_ACTION, []string{strconv.Itoa(l)}); errAnno != nil {
			panic(errAnno)
		}
	}
	for _, flagNamePre := range prerequisites { // check prerequisite flags
		fPre := c.Flags().Lookup(flagNamePre)
		if fPre == nil {
			panic(fmt.Sprintf("Failed to find flag %q and mark it as prerequisite of other flags", flagNamePre))
		}
		if _, ok := fPre.Annotations[_ANNOTATION_DEPENDANT]; !ok {
			fPre.Annotations = map[string][]string{}
		}
		fPre.Annotations[_ANNOTATION_DEPENDANT] = append(fPre.Annotations[_ANNOTATION_DEPENDANT], dependants...)
	}
}

// ValidateFlagGroups validates the mutuallyExclusive/oneRequired/requiredAsGroup logic and returns the
// first error encountered.
func (c *Command) ValidateFlagGroups() error {
	if c.DisableFlagParsing {
		return nil
	}

	flags := c.Flags()

	// groupStatus format is the list of flags as a unique ID,
	// then a map of each flag name and whether it is set or not.
	groupStatus := map[string]map[string]bool{}
	oneRequiredGroupStatus := map[string]map[string]bool{}
	mutuallyExclusiveGroupStatus := map[string]map[string]bool{}
	prerequisiteGroupStatus := map[string]map[string]bool{}
	flags.VisitAll(func(pflag *flag.Flag) {
		processFlagForGroupAnnotation(flags, pflag, requiredAsGroup, groupStatus)
		processFlagForGroupAnnotation(flags, pflag, oneRequired, oneRequiredGroupStatus)
		processFlagForGroupAnnotation(flags, pflag, mutuallyExclusive, mutuallyExclusiveGroupStatus)
		processFlagForGroupAnnotation(flags, pflag, _ANNOTATION_DEPENDANT, prerequisiteGroupStatus)
	})
	if err := validateRequiredFlagGroups(groupStatus); err != nil {
		return err
	}
	if err := validateOneRequiredFlagGroups(oneRequiredGroupStatus); err != nil {
		return err
	}
	if err := validateExclusiveFlagGroups(mutuallyExclusiveGroupStatus); err != nil {
		return err
	}
	if errPrereq := c.validatePrerequisiteFlagGroups(prerequisiteGroupStatus); errPrereq != nil {
		return errPrereq
	}
	return nil
}

func hasAllFlags(fs *flag.FlagSet, flagnames ...string) bool {
	for _, fname := range flagnames {
		f := fs.Lookup(fname)
		if f == nil {
			return false
		}
	}
	return true
}

func processFlagForGroupAnnotation(flags *flag.FlagSet, pflag *flag.Flag, annotation string, groupStatus map[string]map[string]bool) {
	groupInfo, found := pflag.Annotations[annotation]
	if found {
		for _, group := range groupInfo {
			if groupStatus[group] == nil {
				flagnames := strings.Split(group, " ")

				// Only consider this flag group at all if all the flags are defined.
				if !hasAllFlags(flags, flagnames...) {
					continue
				}

				groupStatus[group] = make(map[string]bool, len(flagnames))
				for _, name := range flagnames {
					groupStatus[group][name] = false
				}
			}

			groupStatus[group][pflag.Name] = pflag.Changed
		}
	}
}

func validateRequiredFlagGroups(data map[string]map[string]bool) error {
	keys := sortedKeys(data)
	for _, flagList := range keys {
		flagnameAndStatus := data[flagList]

		unset := []string{}
		for flagname, isSet := range flagnameAndStatus {
			if !isSet {
				unset = append(unset, flagname)
			}
		}
		if len(unset) == len(flagnameAndStatus) || len(unset) == 0 {
			continue
		}

		// Sort values, so they can be tested/scripted against consistently.
		sort.Strings(unset)
		return fmt.Errorf("if any flags in the group [%v] are set they must all be set; missing %v", flagList, unset)
	}

	return nil
}

func validateOneRequiredFlagGroups(data map[string]map[string]bool) error {
	keys := sortedKeys(data)
	for _, flagList := range keys {
		flagnameAndStatus := data[flagList]
		var set []string
		for flagname, isSet := range flagnameAndStatus {
			if isSet {
				set = append(set, flagname)
			}
		}
		if len(set) >= 1 {
			continue
		}

		// Sort values, so they can be tested/scripted against consistently.
		sort.Strings(set)
		return fmt.Errorf("at least one of the flags in the group [%v] is required", flagList)
	}
	return nil
}

func validateExclusiveFlagGroups(data map[string]map[string]bool) error {
	keys := sortedKeys(data)
	for _, flagList := range keys {
		flagnameAndStatus := data[flagList]
		var set []string
		for flagname, isSet := range flagnameAndStatus {
			if isSet {
				set = append(set, flagname)
			}
		}
		if len(set) == 0 || len(set) == 1 {
			continue
		}

		// Sort values, so they can be tested/scripted against consistently.
		sort.Strings(set)
		return fmt.Errorf("if any flags in the group [%v] are set none of the others can be; %v were all set", flagList, set)
	}
	return nil
}

func (c *Command) validatePrerequisiteFlagGroups(data map[string]map[string]bool) error {
	for flagNameDep, flagPrereqExistence := range data {
		fDep := c.Flags().Lookup(flagNameDep)
		isPrerequisiteFound := false
		flagsetPrerequisite := fDep.Annotations[_ANNOTATION_PREREQUISITE]
		for _, flagNamePre := range flagsetPrerequisite {
			if v, b := flagPrereqExistence[flagNamePre]; b && v {
				isPrerequisiteFound = true
				break
			}
		}
		if !isPrerequisiteFound {
			iPrereqMissingAction, _ := strconv.Atoi(fDep.Annotations[_ANNOTATION_PREREQUISITE_MISSING_ACTION][0])
			errMsg := fmt.Sprintf("flag %q is only effective if any of the flags in the group %v is set", flagNameDep, flagsetPrerequisite)
			switch iPrereqMissingAction {
			case PREREQUISITE_MISSING_PANIC:
				return fmt.Errorf(errMsg)
			case PREREQUISITE_MISSING_MURMUR:
				fmt.Fprintln(os.Stderr, errMsg)
				fallthrough
			case PREREQUISITE_MISSING_IGNORE:
				fallthrough
			default:

			}
		}
	}
	return nil
}

func sortedKeys(m map[string]map[string]bool) []string {
	keys := make([]string, len(m))
	i := 0
	for k := range m {
		keys[i] = k
		i++
	}
	sort.Strings(keys)
	return keys
}

// enforceFlagGroupsForCompletion will do the following:
// - when a flag in a group is present, other flags in the group will be marked required
// - when none of the flags in a one-required group are present, all flags in the group will be marked required
// - when a flag in a mutually exclusive group is present, other flags in the group will be marked as hidden
// This allows the standard completion logic to behave appropriately for flag groups
func (c *Command) enforceFlagGroupsForCompletion() {
	if c.DisableFlagParsing {
		return
	}

	flags := c.Flags()
	groupStatus := map[string]map[string]bool{}
	oneRequiredGroupStatus := map[string]map[string]bool{}
	mutuallyExclusiveGroupStatus := map[string]map[string]bool{}
	c.Flags().VisitAll(func(pflag *flag.Flag) {
		processFlagForGroupAnnotation(flags, pflag, requiredAsGroup, groupStatus)
		processFlagForGroupAnnotation(flags, pflag, oneRequired, oneRequiredGroupStatus)
		processFlagForGroupAnnotation(flags, pflag, mutuallyExclusive, mutuallyExclusiveGroupStatus)
	})

	// If a flag that is part of a group is present, we make all the other flags
	// of that group required so that the shell completion suggests them automatically
	for flagList, flagnameAndStatus := range groupStatus {
		for _, isSet := range flagnameAndStatus {
			if isSet {
				// One of the flags of the group is set, mark the other ones as required
				for _, fName := range strings.Split(flagList, " ") {
					_ = c.MarkFlagRequired(fName)
				}
			}
		}
	}

	// If none of the flags of a one-required group are present, we make all the flags
	// of that group required so that the shell completion suggests them automatically
	for flagList, flagnameAndStatus := range oneRequiredGroupStatus {
		isSet := false

		for _, isSet = range flagnameAndStatus {
			if isSet {
				break
			}
		}

		// None of the flags of the group are set, mark all flags in the group
		// as required
		if !isSet {
			for _, fName := range strings.Split(flagList, " ") {
				_ = c.MarkFlagRequired(fName)
			}
		}
	}

	// If a flag that is mutually exclusive to others is present, we hide the other
	// flags of that group so the shell completion does not suggest them
	for flagList, flagnameAndStatus := range mutuallyExclusiveGroupStatus {
		for flagName, isSet := range flagnameAndStatus {
			if isSet {
				// One of the flags of the mutually exclusive group is set, mark the other ones as hidden
				// Don't mark the flag that is already set as hidden because it may be an
				// array or slice flag and therefore must continue being suggested
				for _, fName := range strings.Split(flagList, " ") {
					if fName != flagName {
						flag := c.Flags().Lookup(fName)
						flag.Hidden = true
					}
				}
			}
		}
	}
}