/*
Copyright IBM Corp. All Rights Reserved.

SPDX-License-Identifier: Apache-2.0
*/

package lib

import (
	"fmt"
	"strconv"
	"strings"

	"github.com/cloudflare/cfssl/log"
	"github.com/hyperledger/fabric-ca/api"
	"github.com/hyperledger/fabric-ca/lib/attr"
	"github.com/hyperledger/fabric-ca/lib/caerrors"
	"github.com/hyperledger/fabric-ca/lib/server/db"
	"github.com/hyperledger/fabric-ca/lib/server/db/util"
	"github.com/hyperledger/fabric-ca/lib/server/user"
	cadbuser "github.com/hyperledger/fabric-ca/lib/server/user"
	"github.com/hyperledger/fabric-ca/lib/spi"
	"github.com/pkg/errors"
)

func newAffiliationsEndpoint(s *Server) *serverEndpoint {
	return &serverEndpoint{
		Path:      "affiliations/{affiliation}",
		Methods:   []string{"GET", "DELETE", "PUT"},
		Handler:   affiliationsHandler,
		Server:    s,
		successRC: 200,
	}
}

func newAffiliationsStreamingEndpoint(s *Server) *serverEndpoint {
	return &serverEndpoint{
		Path:      "affiliations",
		Methods:   []string{"GET", "POST"},
		Handler:   affiliationsStreamingHandler,
		Server:    s,
		successRC: 200,
	}
}

func affiliationsHandler(ctx *serverRequestContextImpl) (interface{}, error) {
	var err error
	// Authenticate
	callerID, err := ctx.TokenAuthentication()
	log.Debugf("Received affiliation update request from %s", callerID)
	if err != nil {
		return nil, err
	}
	caname, err := ctx.getCAName()
	if err != nil {
		return nil, err
	}
	caller, err := ctx.GetCaller()
	if err != nil {
		return nil, err
	}
	err = ctx.HasRole(attr.AffiliationMgr)
	if err != nil {
		return nil, err
	}
	// Process Request
	resp, err := processAffiliationRequest(ctx, caname, caller)
	if err != nil {
		return nil, err
	}

	return resp, nil
}

func affiliationsStreamingHandler(ctx *serverRequestContextImpl) (interface{}, error) {
	var err error

	// Authenticate
	callerID, err := ctx.TokenAuthentication()
	log.Debugf("Received affiliation update request from %s", callerID)
	if err != nil {
		return nil, err
	}
	caname, err := ctx.getCAName()
	if err != nil {
		return nil, err
	}
	caller, err := ctx.GetCaller()
	if err != nil {
		return nil, err
	}
	err = ctx.HasRole(attr.AffiliationMgr)
	if err != nil {
		return nil, err
	}
	// Process Request
	resp, err := processStreamingAffiliationRequest(ctx, caname, caller)
	if err != nil {
		return nil, err
	}

	return resp, nil
}

// processStreamingAffiliationRequest will process the configuration request
func processStreamingAffiliationRequest(ctx *serverRequestContextImpl, caname string, caller user.User) (interface{}, error) {
	log.Debug("Processing affiliation configuration update request")

	method := ctx.req.Method
	switch method {
	case "GET":
		return processGetAllAffiliationsRequest(ctx, caller, caname)
	case "POST":
		return processAffiliationPostRequest(ctx, caname)
	default:
		return nil, errors.Errorf("Invalid request: %s", method)
	}
}

// processRequest will process the configuration request
func processAffiliationRequest(ctx *serverRequestContextImpl, caname string, caller user.User) (interface{}, error) {
	log.Debug("Processing affiliation configuration update request")

	method := ctx.req.Method
	switch method {
	case "GET":
		return processGetAffiliationRequest(ctx, caller, caname)
	case "DELETE":
		return processAffiliationDeleteRequest(ctx, caname)
	case "PUT":
		return processAffiliationPutRequest(ctx, caname)
	default:
		return nil, errors.Errorf("Invalid request: %s", method)
	}
}

func processGetAllAffiliationsRequest(ctx *serverRequestContextImpl, caller user.User, caname string) (*api.AffiliationResponse, error) {
	log.Debug("Processing GET all affiliations request")

	resp, err := getAffiliations(ctx, caller, caname)
	if err != nil {
		return nil, err
	}

	return resp, nil
}

func processGetAffiliationRequest(ctx *serverRequestContextImpl, caller user.User, caname string) (*api.AffiliationResponse, error) {
	log.Debug("Processing GET affiliation request")

	affiliation, err := ctx.GetVar("affiliation")
	if err != nil {
		return nil, err
	}

	resp, err := getAffiliation(ctx, caller, affiliation, caname)
	if err != nil {
		return nil, err
	}

	return resp, nil
}

func getAffiliations(ctx *serverRequestContextImpl, caller user.User, caname string) (*api.AffiliationResponse, error) {
	log.Debug("Requesting all affiliations that the caller is authorized view")
	var err error

	registry := ctx.ca.registry
	callerAff := cadbuser.GetAffiliation(caller)
	rows, err := registry.GetAllAffiliations(callerAff)
	if err != nil {
		return nil, caerrors.NewHTTPErr(500, caerrors.ErrGettingUser, "Failed to get affiliation: %s", err)
	}

	an := &affiliationNode{}
	for rows.Next() {
		var aff db.AffiliationRecord
		err := rows.StructScan(&aff)
		if err != nil {
			return nil, caerrors.NewHTTPErr(500, caerrors.ErrGettingAffiliation, "Failed to get read row: %s", err)
		}

		an.insertByName(aff.Name)
	}
	root := an.GetRoot()
	if root == nil {
		return nil, caerrors.NewHTTPErr(500, caerrors.ErrGettingAffiliation, "No affiliations are configured on the CA")
	}

	resp := &api.AffiliationResponse{
		CAName: caname,
	}
	resp.Name = root.Name
	resp.Affiliations = root.Affiliations
	resp.Identities = root.Identities

	return resp, nil
}

func getAffiliation(ctx *serverRequestContextImpl, caller user.User, requestedAffiliation, caname string) (*api.AffiliationResponse, error) {
	log.Debugf("Requesting affiliation '%s'", requestedAffiliation)

	registry := ctx.ca.registry
	err := ctx.ContainsAffiliation(requestedAffiliation)
	if err != nil {
		return nil, err
	}

	result, err := registry.GetAffiliationTree(requestedAffiliation)
	if err != nil {
		return nil, caerrors.NewHTTPErr(500, caerrors.ErrGettingAffiliation, "Failed to get affiliation: %s", err)
	}

	resp, err := getResponse(result, caname)
	if err != nil {
		return nil, err
	}

	return resp, nil
}

func processAffiliationDeleteRequest(ctx *serverRequestContextImpl, caname string) (*api.AffiliationResponse, error) {
	log.Debug("Processing DELETE request")

	if !ctx.ca.Config.Cfg.Affiliations.AllowRemove {
		return nil, caerrors.NewAuthorizationErr(caerrors.ErrUpdateConfigRemoveAff, "Affiliation removal is disabled")
	}

	removeAffiliation, err := ctx.GetVar("affiliation")
	if err != nil {
		return nil, err
	}
	log.Debugf("Request to remove affiliation '%s'", removeAffiliation)

	callerAff := cadbuser.GetAffiliation(ctx.caller)
	if callerAff == removeAffiliation {
		return nil, caerrors.NewAuthorizationErr(caerrors.ErrUpdateConfigRemoveAff, "Can't remove affiliation '%s' because the caller is associated with this affiliation", removeAffiliation)
	}

	err = ctx.ContainsAffiliation(removeAffiliation)
	if err != nil {
		return nil, err
	}

	force, err := ctx.GetBoolQueryParm("force")
	if err != nil {
		return nil, err
	}

	_, isRegistrar, err := ctx.isRegistrar()
	if err != nil {
		httpErr := getHTTPErr(err)
		if httpErr.GetRemoteCode() != 20 {
			return nil, err
		}
	}

	identityRemoval := ctx.ca.Config.Cfg.Identities.AllowRemove
	result, err := ctx.ca.registry.DeleteAffiliation(removeAffiliation, force, identityRemoval, isRegistrar)
	if err != nil {
		return nil, err
	}

	resp, err := getResponse(result, caname)
	if err != nil {
		return nil, err
	}

	return resp, nil
}

func processAffiliationPostRequest(ctx *serverRequestContextImpl, caname string) (*api.AffiliationResponse, error) {
	log.Debug("Processing POST request")

	ctx.endpoint.successRC = 201

	var req api.AddAffiliationRequestNet
	err := ctx.ReadBody(&req)
	if err != nil {
		return nil, err
	}

	addAffiliation := req.Name
	log.Debugf("Request to add affiliation '%s'", addAffiliation)

	registry := ctx.ca.registry
	result, err := registry.GetAffiliation(addAffiliation)
	if err != nil && !util.IsGetError(err) {
		return nil, err
	}
	if result != nil {
		return nil, caerrors.NewHTTPErr(409, caerrors.ErrUpdateConfigAddAff, "Affiliation already exists")
	}

	err = ctx.ContainsAffiliation(addAffiliation)
	if err != nil {
		return nil, err
	}

	force, err := ctx.GetBoolQueryParm("force")
	if err != nil {
		return nil, err
	}

	addAffiliationSlice := strings.Split(addAffiliation, ".")
	var parentAffiliationPath string

	affLevel := ctx.ca.server.levels.Affiliation
	if force {
		// With force option, add any parent affiliations that don't exist
		var affiliationPath string
		for _, addAff := range addAffiliationSlice {
			affiliationPath = affiliationPath + addAff
			err := registry.InsertAffiliation(affiliationPath, parentAffiliationPath, affLevel)
			if err != nil {
				return nil, caerrors.NewHTTPErr(500, caerrors.ErrUpdateConfigAddAff, "Failed to add affiliations '%s': %s", addAffiliation, err)
			}
			parentAffiliationPath = affiliationPath
			affiliationPath = affiliationPath + "."
		}
	} else {
		// If the affiliation being added has a parent affiliation, check to make sure that parent affiliation exists
		if len(addAffiliationSlice) > 1 {
			parentAffiliationPath = strings.Join(addAffiliationSlice[:len(addAffiliationSlice)-1], ".") // Get the path up until the last affiliation
			_, err = registry.GetAffiliation(parentAffiliationPath)
			if err != nil {
				httpErr := getHTTPErr(err)
				if httpErr.GetStatusCode() == 400 {
					return nil, caerrors.NewHTTPErr(400, caerrors.ErrUpdateConfigAddAff, "Parent affiliation does not exist, 'force' option required on request to add affiliation")
				}
				return nil, err
			}
			err := registry.InsertAffiliation(addAffiliation, parentAffiliationPath, affLevel)
			if err != nil {
				return nil, caerrors.NewHTTPErr(500, caerrors.ErrUpdateConfigAddAff, "Failed to add affiliation '%s': %s", addAffiliation, err)
			}
		} else {
			err := registry.InsertAffiliation(addAffiliation, "", affLevel)
			if err != nil {
				return nil, caerrors.NewHTTPErr(500, caerrors.ErrUpdateConfigAddAff, "Failed to add affiliation '%s': %s", addAffiliation, err)
			}
		}

	}

	resp := &api.AffiliationResponse{CAName: caname}
	resp.Name = addAffiliation

	return resp, nil
}

func processAffiliationPutRequest(ctx *serverRequestContextImpl, caname string) (*api.AffiliationResponse, error) {
	log.Debug("Processing PUT request")

	modifyAffiliation, err := ctx.GetVar("affiliation")
	if err != nil {
		return nil, err
	}

	var req api.ModifyAffiliationRequestNet
	err = ctx.ReadBody(&req)
	if err != nil {
		return nil, err
	}
	newAffiliation := req.NewName
	log.Debugf("Request to modify affiliation '%s' to '%s'", modifyAffiliation, newAffiliation)

	err = ctx.ContainsAffiliation(modifyAffiliation)
	if err != nil {
		return nil, err
	}

	err = ctx.ContainsAffiliation(newAffiliation)
	if err != nil {
		return nil, err
	}

	force := false
	forceStr := ctx.req.URL.Query().Get("force")
	if forceStr != "" {
		force, err = strconv.ParseBool(forceStr)
		if err != nil {
			return nil, caerrors.NewHTTPErr(500, caerrors.ErrUpdateConfigAddAff, "The 'force' query parameter value must be a boolean: %s", err)
		}

	}

	_, isRegistrar, err := ctx.isRegistrar()
	if err != nil {
		httpErr := getHTTPErr(err)
		if httpErr.GetLocalCode() != 20 {
			return nil, err
		}
	}

	registry := ctx.ca.registry
	result, err := registry.ModifyAffiliation(modifyAffiliation, newAffiliation, force, isRegistrar)
	if err != nil {
		return nil, errors.WithMessage(err, fmt.Sprintf("Failed to modify affiliation from '%s' to '%s'", modifyAffiliation, newAffiliation))
	}

	resp, err := getResponse(result, caname)
	if err != nil {
		return nil, err
	}

	return resp, nil
}

func getResponse(result *user.DbTxResult, caname string) (*api.AffiliationResponse, error) {
	resp := &api.AffiliationResponse{CAName: caname}
	// Get all root affiliation names from the result
	rootNames := getRootAffiliationNames(result.Affiliations)
	if len(rootNames) == 0 {
		return resp, nil
	}
	if len(rootNames) != 1 {
		return nil, errors.Errorf("multiple root affiliations found: %+v", rootNames)
	}
	affInfo := &api.AffiliationInfo{}
	err := fillAffiliationInfo(affInfo, rootNames[0], result, result.Affiliations)
	if err != nil {
		return nil, err
	}
	resp.AffiliationInfo = *affInfo
	return resp, nil
}

// Get all of the root affiliation names from this list of affiliations
func getRootAffiliationNames(affiliations []spi.Affiliation) []string {
	roots := []string{}
	for _, aff1 := range affiliations {
		isRoot := true
		for _, aff2 := range affiliations {
			if isChildAffiliation(aff2.GetName(), aff1.GetName()) {
				isRoot = false
				break
			}
		}
		if isRoot {
			roots = append(roots, aff1.GetName())
		}
	}
	return roots
}

// Fill 'info' with affiliation info associated with affiliation 'name' hierarchically.
// Use 'affiliations' to find child affiliations for this affiliation, and
// 'identities' to find identities associated with this affiliation.
func fillAffiliationInfo(info *api.AffiliationInfo, name string, result *user.DbTxResult, affiliations []spi.Affiliation) error {
	info.Name = name
	// Add identities which have this affiliation
	identities := []api.IdentityInfo{}
	for _, identity := range result.Identities {
		idAff := strings.Join(identity.GetAffiliationPath(), ".")
		if idAff == name {
			id, err := getIDInfo(identity)
			if err != nil {
				return err
			}
			identities = append(identities, *id)
		}
	}
	if len(identities) > 0 {
		info.Identities = identities
	}
	// Create child affiliations (if any)
	children := []api.AffiliationInfo{}
	var child spi.Affiliation
	for {
		child = nil
		// Search for a child affiliations
		for idx, aff := range affiliations {
			affName := aff.GetName()
			if isChildAffiliation(name, affName) {
				child = aff
				// Remove this child affiliation
				affiliations = append(affiliations[:idx], affiliations[idx+1:]...)
				break
			}
		}
		if child == nil {
			// No more children of this affiliation 'name' found
			break
		}
		// Found a child of affiliation 'name'
		childAff := api.AffiliationInfo{Name: child.GetName()}
		err := fillAffiliationInfo(&childAff, child.GetName(), result, affiliations)
		if err != nil {
			return err
		}
		children = append(children, childAff)
	}
	if len(children) > 0 {
		info.Affiliations = children
	}
	return nil
}

// Determine if the affiliation with name 'child' is a child of affiliation with name 'name'
func isChildAffiliation(name, child string) bool {
	if !strings.HasPrefix(child, name+".") {
		return false
	}
	nameParts := strings.Split(name, ".")
	childParts := strings.Split(child, ".")
	if len(childParts) != len(nameParts)+1 {
		return false
	}
	return true
}

func getIDInfo(user user.User) (*api.IdentityInfo, error) {
	allAttributes, err := user.GetAttributes(nil)
	if err != nil {
		return nil, err
	}
	return &api.IdentityInfo{
		ID:             user.GetName(),
		Type:           user.GetType(),
		Affiliation:    cadbuser.GetAffiliation(user),
		Attributes:     allAttributes,
		MaxEnrollments: user.GetMaxEnrollments(),
	}, nil
}

type affiliationNode struct {
	children map[string]*affiliationNode
}

func (an *affiliationNode) insertByName(name string) {
	an.insertByPath(strings.Split(name, "."))
}

func (an *affiliationNode) insertByPath(path []string) {
	if len(path) == 0 {
		return
	}
	if an.children == nil {
		an.children = map[string]*affiliationNode{}
	}
	node := an.children[path[0]]
	if node == nil {
		node = &affiliationNode{}
		an.children[path[0]] = node
	}
	node.insertByPath(path[1:])
}

func (an *affiliationNode) GetRoot() *api.AffiliationInfo {
	result := &api.AffiliationInfo{}
	an.fill([]string{}, result)
	switch len(result.Affiliations) {
	case 0:
		return nil
	case 1:
		return &result.Affiliations[0]
	default:
		return result
	}
}

func (an *affiliationNode) fill(path []string, ai *api.AffiliationInfo) {
	ai.Name = strings.Join(path, ".")
	if len(an.children) > 0 {
		ai.Affiliations = make([]api.AffiliationInfo, len(an.children))
		idx := 0
		for key, child := range an.children {
			child.fill(append(path, key), &ai.Affiliations[idx])
			idx++
		}
	}
}