// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: BUSL-1.1

package command

import (
	"encoding/json"
	"fmt"
	"strconv"
	"strings"

	"github.com/hashicorp/vault/api"

	"github.com/ghodss/yaml"
	"github.com/ryanuber/columnize"
)

type PKIListIntermediateCommand struct {
	*BaseCommand

	flagConfig          string
	flagReturnIndicator string
	flagDefaultDisabled bool
	flagList            bool

	flagUseNames bool

	flagSignatureMatch    bool
	flagIndirectSignMatch bool
	flagKeyIdMatch        bool
	flagSubjectMatch      bool
	flagPathMatch         bool
}

func (c *PKIListIntermediateCommand) Synopsis() string {
	return "Determine which of a list of certificates, were issued by a given parent certificate"
}

func (c *PKIListIntermediateCommand) Help() string {
	helpText := `
Usage: vault pki list-intermediates PARENT [CHILD] [CHILD] [CHILD] ...

  Lists the set of intermediate CAs issued by this parent issuer.

  PARENT is the certificate that might be the issuer that everything should
  be verified against.

  CHILD is an optional list of paths to certificates to be compared to the
  PARENT, or pki mounts to look for certificates on. If CHILD is omitted
  entirely, the list will be constructed from all accessible pki mounts.

  This returns a list of issuing certificates, and whether they are a match.
  By default, the type of match required is whether the PARENT has the
  expected subject, key_id, and could have (directly) signed this issuer. 
  The match criteria can be updated by changed the corresponding flag.

` + c.Flags().Help()
	return strings.TrimSpace(helpText)
}

func (c *PKIListIntermediateCommand) Flags() *FlagSets {
	set := c.flagSet(FlagSetHTTP | FlagSetOutputFormat)
	f := set.NewFlagSet("Command Options")

	f.BoolVar(&BoolVar{
		Name:    "subject_match",
		Target:  &c.flagSubjectMatch,
		Default: true,
		EnvVar:  "",
		Usage:   `Whether the subject name of the potential parent cert matches the issuer name of the child cert.`,
	})

	f.BoolVar(&BoolVar{
		Name:    "key_id_match",
		Target:  &c.flagKeyIdMatch,
		Default: true,
		EnvVar:  "",
		Usage:   `Whether the subject key id (SKID) of the potential parent cert matches the authority key id (AKID) of the child cert.`,
	})

	f.BoolVar(&BoolVar{
		Name:    "path_match",
		Target:  &c.flagPathMatch,
		Default: false,
		EnvVar:  "",
		Usage:   `Whether the potential parent appears in the certificate chain field (ca_chain) of the issued cert.`,
	})

	f.BoolVar(&BoolVar{
		Name:    "direct_sign",
		Target:  &c.flagSignatureMatch,
		Default: true,
		EnvVar:  "",
		Usage:   `Whether the key of the potential parent directly signed this issued certificate.`,
	})

	f.BoolVar(&BoolVar{
		Name:    "indirect_sign",
		Target:  &c.flagIndirectSignMatch,
		Default: true,
		EnvVar:  "",
		Usage:   `Whether trusting the parent certificate is sufficient to trust the child certificate.`,
	})

	f.BoolVar(&BoolVar{
		Name:    "use_names",
		Target:  &c.flagUseNames,
		Default: false,
		EnvVar:  "",
		Usage:   `Whether the list of issuers returned is referred to by name (when it exists) rather than by uuid.`,
	})

	return set
}

func (c *PKIListIntermediateCommand) Run(args []string) int {
	f := c.Flags()
	if err := f.Parse(args); err != nil {
		c.UI.Error(err.Error())
		return 1
	}

	args = f.Args()

	if len(args) < 1 {
		c.UI.Error("Not enough arguments (expected potential parent, got nothing)")
		return 1
	} else if len(args) > 2 {
		for _, arg := range args {
			if strings.HasPrefix(arg, "-") {
				c.UI.Warn(fmt.Sprintf("Options (%v) must be specified before positional arguments (%v)", arg, args[0]))
				break
			}
		}
	}

	client, err := c.Client()
	if err != nil {
		c.UI.Error(fmt.Sprintf("Failed to obtain client: %s", err))
		return 1
	}

	issuer := sanitizePath(args[0])
	var issued []string
	if len(args) > 1 {
		for _, arg := range args[1:] {
			cleanPath := sanitizePath(arg)
			// Arg Might be a Fully Qualified Path
			if strings.Contains(cleanPath, "/issuer/") ||
				strings.Contains(cleanPath, "/certs/") ||
				strings.Contains(cleanPath, "/revoked/") {
				issued = append(issued, cleanPath)
			} else { // Or Arg Might be a Mount
				mountCaList, err := c.getIssuerListFromMount(client, arg)
				if err != nil {
					c.UI.Error(err.Error())
					return 1
				}
				issued = append(issued, mountCaList...)
			}
		}
	} else {
		mountListRaw, err := client.Logical().Read("/sys/mounts/")
		if err != nil {
			c.UI.Error(fmt.Sprintf("Failed to Read List of Mounts With Potential Issuers: %v", err))
			return 1
		}
		for path, rawValueMap := range mountListRaw.Data {
			valueMap := rawValueMap.(map[string]interface{})
			if valueMap["type"].(string) == "pki" {
				mountCaList, err := c.getIssuerListFromMount(client, sanitizePath(path))
				if err != nil {
					c.UI.Error(err.Error())
					return 1
				}
				issued = append(issued, mountCaList...)
			}
		}
	}

	childrenMatches := make(map[string]bool)

	constraintMap := map[string]bool{
		// This comparison isn't strictly correct, despite a standard ordering these are sets
		"subject_match":   c.flagSubjectMatch,
		"path_match":      c.flagPathMatch,
		"trust_match":     c.flagIndirectSignMatch,
		"key_id_match":    c.flagKeyIdMatch,
		"signature_match": c.flagSignatureMatch,
	}

	issuerResp, err := readIssuer(client, issuer)
	if err != nil {
		c.UI.Error(fmt.Sprintf("Failed to read parent issuer on path %s: %s", issuer, err.Error()))
		return 1
	}

	for _, child := range issued {
		path := sanitizePath(child)
		if path != "" {
			verifyResults, err := verifySignBetween(client, issuerResp, path)
			if err != nil {
				c.UI.Error(fmt.Sprintf("Failed to run verification on path %v: %v", path, err))
				return 1
			}
			childrenMatches[path] = checkIfResultsMatchFilters(verifyResults, constraintMap)
		}
	}

	err = c.outputResults(childrenMatches)
	if err != nil {
		c.UI.Error(err.Error())
		return 1
	}

	return 0
}

func (c *PKIListIntermediateCommand) getIssuerListFromMount(client *api.Client, mountString string) ([]string, error) {
	var issuerList []string
	issuerListEndpoint := sanitizePath(mountString) + "/issuers"
	rawIssuersResp, err := client.Logical().List(issuerListEndpoint)
	if err != nil {
		return issuerList, fmt.Errorf("failed to read list of issuers within mount %v: %v", mountString, err)
	}
	if rawIssuersResp == nil { // No Issuers (Empty Mount)
		return issuerList, nil
	}
	issuersMap := rawIssuersResp.Data["keys"]
	certList := issuersMap.([]interface{})
	for _, certId := range certList {
		identifier := certId.(string)
		if c.flagUseNames {
			issuerReadResp, err := client.Logical().Read(sanitizePath(mountString) + "/issuer/" + identifier)
			if err != nil {
				c.UI.Warn(fmt.Sprintf("Unable to Fetch Issuer to Recover Name at: %v", sanitizePath(mountString)+"/issuer/"+identifier))
			}
			if issuerReadResp != nil {
				issuerName := issuerReadResp.Data["issuer_name"].(string)
				if issuerName != "" {
					identifier = issuerName
				}
			}
		}
		issuerList = append(issuerList, sanitizePath(mountString)+"/issuer/"+identifier)
	}
	return issuerList, nil
}

func checkIfResultsMatchFilters(verifyResults, constraintMap map[string]bool) bool {
	for key, required := range constraintMap {
		if required && !verifyResults[key] {
			return false
		}
	}
	return true
}

func (c *PKIListIntermediateCommand) outputResults(results map[string]bool) error {
	switch Format(c.UI) {
	case "", "table":
		return c.outputResultsTable(results)
	case "json":
		return c.outputResultsJSON(results)
	case "yaml":
		return c.outputResultsYAML(results)
	default:
		return fmt.Errorf("unknown output format: %v", Format(c.UI))
	}
}

func (c *PKIListIntermediateCommand) outputResultsTable(results map[string]bool) error {
	data := []string{"intermediate" + hopeDelim + "match?"}
	for field, finding := range results {
		row := field + hopeDelim + strconv.FormatBool(finding)
		data = append(data, row)
	}
	c.UI.Output(tableOutput(data, &columnize.Config{
		Delim: hopeDelim,
	}))
	c.UI.Output("\n")

	return nil
}

func (c *PKIListIntermediateCommand) outputResultsJSON(results map[string]bool) error {
	bytes, err := json.MarshalIndent(results, "", "  ")
	if err != nil {
		return err
	}

	c.UI.Output(string(bytes))
	return nil
}

func (c *PKIListIntermediateCommand) outputResultsYAML(results map[string]bool) error {
	bytes, err := yaml.Marshal(results)
	if err != nil {
		return err
	}

	c.UI.Output(string(bytes))
	return nil
}