/*
Copyright 2016 The Kubernetes 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 sanity

import (
	"fmt"
	"os"
	"regexp"
	"strings"

	"github.com/spf13/cobra"
	"github.com/spf13/pflag"

	"k8s.io/kubectl/pkg/util/templates"
)

// CmdCheck is the commom type of functions to check cobra commands
type CmdCheck func(cmd *cobra.Command) []error

// GlobalCheck is the common type of functions to check global flags
type GlobalCheck func() []error

var (
	// AllCmdChecks is the list of CmdCheck type functions
	AllCmdChecks = []CmdCheck{
		CheckLongDesc,
		CheckExamples,
		CheckFlags,
	}

	// AllGlobalChecks is the list of GlobalCheck type functions
	AllGlobalChecks = []GlobalCheck{
		CheckGlobalVarFlags,
	}
)

// RunGlobalChecks runs all the GlobalCheck functions passed and checks for error
func RunGlobalChecks(globalChecks []GlobalCheck) []error {
	fmt.Fprint(os.Stdout, "---+ RUNNING GLOBAL CHECKS\n")
	errors := []error{}
	for _, check := range globalChecks {
		errors = append(errors, check()...)
	}
	return errors
}

// RunCmdChecks runs all the CmdCheck functions passed, skipping skippable commands and looks for error
func RunCmdChecks(cmd *cobra.Command, cmdChecks []CmdCheck, skipCmd []string) []error {
	cmdPath := cmd.CommandPath()

	for _, skipCmdPath := range skipCmd {
		if cmdPath == skipCmdPath {
			fmt.Fprintf(os.Stdout, "---+ skipping command %s\n", cmdPath)
			return []error{}
		}
	}

	errors := []error{}

	if cmd.HasSubCommands() {
		for _, subCmd := range cmd.Commands() {
			errors = append(errors, RunCmdChecks(subCmd, cmdChecks, skipCmd)...)
		}
	}

	fmt.Fprintf(os.Stdout, "---+ RUNNING COMMAND CHECKS on %q\n", cmdPath)

	for _, check := range cmdChecks {
		if err := check(cmd); len(err) > 0 {
			errors = append(errors, err...)
		}
	}

	return errors
}

// CheckLongDesc checks if the long description is valid
func CheckLongDesc(cmd *cobra.Command) []error {
	fmt.Fprint(os.Stdout, "   ↳ checking long description\n")
	cmdPath := cmd.CommandPath()
	long := cmd.Long
	if len(long) > 0 {
		if strings.Trim(long, " \t\n") != long {
			return []error{fmt.Errorf(`command %q: long description is not normalized, make sure you are calling templates.LongDesc (from pkg/cmd/templates) before assigning cmd.Long`, cmdPath)}
		}
	}
	return nil
}

// CheckExamples checks if the command examples are valid
func CheckExamples(cmd *cobra.Command) []error {
	fmt.Fprint(os.Stdout, "   ↳ checking examples\n")
	cmdPath := cmd.CommandPath()
	examples := cmd.Example
	errors := []error{}
	if len(examples) > 0 {
		for _, line := range strings.Split(examples, "\n") {
			if !strings.HasPrefix(line, templates.Indentation) {
				errors = append(errors, fmt.Errorf(`command %q: examples are not normalized, make sure you are calling templates.Examples (from pkg/cmd/templates) before assigning cmd.Example`, cmdPath))
			}
			if trimmed := strings.TrimSpace(line); strings.HasPrefix(trimmed, "//") {
				errors = append(errors, fmt.Errorf(`command %q: we use # to start comments in examples instead of //`, cmdPath))
			}
		}
	}
	return errors
}

// CheckFlags checks if the command-line flags are valid
func CheckFlags(cmd *cobra.Command) []error {
	allFlagsSlice := []*pflag.Flag{}

	cmd.Flags().VisitAll(func(f *pflag.Flag) {
		allFlagsSlice = append(allFlagsSlice, f)
	})
	cmd.PersistentFlags().VisitAll(func(f *pflag.Flag) {
		allFlagsSlice = append(allFlagsSlice, f)
	})

	fmt.Fprintf(os.Stdout, "   ↳ checking %d flags\n", len(allFlagsSlice))

	errors := []error{}

	// check flags long names
	regex, err := regexp.Compile(`^[a-z]+[a-z\-]*$`)
	if err != nil {
		errors = append(errors, fmt.Errorf("command %q: unable to compile regex to check flags", cmd.CommandPath()))
		return errors
	}
	for _, flag := range allFlagsSlice {
		name := flag.Name
		if !regex.MatchString(name) {
			errors = append(errors, fmt.Errorf("command %q: flag name %q is invalid, long form of flag names can only contain lowercase characters or dash (must match %v)", cmd.CommandPath(), name, regex))
		}
	}

	return errors
}

// CheckGlobalVarFlags checks if the global flags are valid
func CheckGlobalVarFlags() []error {
	fmt.Fprint(os.Stdout, "   ↳ checking flags from global vars\n")
	errors := []error{}
	pflag.CommandLine.VisitAll(func(f *pflag.Flag) {
		errors = append(errors, fmt.Errorf("flag %q is invalid, please don't register any flag under the global variable \"CommandLine\"", f.Name))
	})
	return errors
}