package service

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strconv"
	"strings"

	"github.com/fleetdm/fleet/v4/server/contexts/ctxerr"
	"github.com/fleetdm/fleet/v4/server/fleet"
	"github.com/fleetdm/fleet/v4/server/ptr"
	kithttp "github.com/go-kit/kit/transport/http"
	"github.com/gorilla/mux"
)

// errBadRoute is used for mux errors
var errBadRoute = errors.New("bad route")

func encodeResponse(ctx context.Context, w http.ResponseWriter, response interface{}) error {
	// The has to happen first, if an error happens we'll redirect to an error
	// page and the error will be logged
	if page, ok := response.(htmlPage); ok {
		w.Header().Set("Content-Type", "text/html; charset=UTF-8")
		writeBrowserSecurityHeaders(w)
		if coder, ok := page.error().(kithttp.StatusCoder); ok {
			w.WriteHeader(coder.StatusCode())
		}
		_, err := io.WriteString(w, page.html())
		return err
	}

	if e, ok := response.(errorer); ok && e.error() != nil {
		encodeError(ctx, e.error(), w)
		return nil
	}

	if render, ok := response.(renderHijacker); ok {
		render.hijackRender(ctx, w)
		return nil
	}

	if e, ok := response.(statuser); ok {
		w.WriteHeader(e.Status())
		if e.Status() == http.StatusNoContent {
			return nil
		}
	}

	enc := json.NewEncoder(w)
	enc.SetIndent("", "  ")
	return enc.Encode(response)
}

// statuser allows response types to implement a custom
// http success status - default is 200 OK
type statuser interface {
	Status() int
}

// loads a html page
type htmlPage interface {
	html() string
	error() error
}

// renderHijacker can be implemented by response values to take control of
// their own rendering.
type renderHijacker interface {
	hijackRender(ctx context.Context, w http.ResponseWriter)
}

func uintFromRequest(r *http.Request, name string) (uint64, error) {
	vars := mux.Vars(r)
	s, ok := vars[name]
	if !ok {
		return 0, errBadRoute
	}
	u, err := strconv.ParseUint(s, 10, 64)
	if err != nil {
		return 0, ctxerr.Wrap(r.Context(), err, "uintFromRequest")
	}
	return u, nil
}

func intFromRequest(r *http.Request, name string) (int64, error) {
	vars := mux.Vars(r)
	s, ok := vars[name]
	if !ok {
		return 0, errBadRoute
	}
	u, err := strconv.ParseInt(s, 10, 64)
	if err != nil {
		return 0, ctxerr.Wrap(r.Context(), err, "intFromRequest")
	}
	return u, nil
}

func stringFromRequest(r *http.Request, name string) (string, error) {
	vars := mux.Vars(r)
	s, ok := vars[name]
	if !ok {
		return "", errBadRoute
	}
	unescaped, err := url.PathUnescape(s)
	if err != nil {
		return "", ctxerr.Wrap(r.Context(), err, "unescape value in path")
	}
	return unescaped, nil
}

// default number of items to include per page
const defaultPerPage = 20

// listOptionsFromRequest parses the list options from the request parameters
func listOptionsFromRequest(r *http.Request) (fleet.ListOptions, error) {
	var err error

	pageString := r.URL.Query().Get("page")
	perPageString := r.URL.Query().Get("per_page")
	orderKey := r.URL.Query().Get("order_key")
	orderDirectionString := r.URL.Query().Get("order_direction")
	afterString := r.URL.Query().Get("after")

	var page int
	if pageString != "" {
		page, err = strconv.Atoi(pageString)
		if err != nil {
			return fleet.ListOptions{}, ctxerr.Wrap(r.Context(), badRequest("non-int page value"))
		}
		if page < 0 {
			return fleet.ListOptions{}, ctxerr.Wrap(r.Context(), badRequest("negative page value"))
		}
	}

	// We default to 0 for per_page so that not specifying any paging
	// information gets all results
	var perPage int
	if perPageString != "" {
		perPage, err = strconv.Atoi(perPageString)
		if err != nil {
			return fleet.ListOptions{}, ctxerr.Wrap(r.Context(), badRequest("non-int per_page value"))
		}
		if perPage <= 0 {
			return fleet.ListOptions{}, ctxerr.Wrap(r.Context(), badRequest("invalid per_page value"))
		}
	}

	if perPage == 0 && pageString != "" {
		// We explicitly set a non-zero default if a page is specified
		// (because the client probably intended for paging, and
		// leaving the 0 would turn that off)
		perPage = defaultPerPage
	}

	if orderKey == "" && orderDirectionString != "" {
		return fleet.ListOptions{}, ctxerr.Wrap(r.Context(), badRequest("order_key must be specified with order_direction"))
	}

	if orderKey == "" && afterString != "" {
		return fleet.ListOptions{}, ctxerr.Wrap(r.Context(), badRequest("order_key must be specified with after"))
	}

	var orderDirection fleet.OrderDirection
	switch orderDirectionString {
	case "desc":
		orderDirection = fleet.OrderDescending
	case "asc":
		orderDirection = fleet.OrderAscending
	case "":
		orderDirection = fleet.OrderAscending
	default:
		return fleet.ListOptions{},
			ctxerr.Wrap(r.Context(), badRequest("unknown order_direction: "+orderDirectionString))

	}

	query := r.URL.Query().Get("query")

	return fleet.ListOptions{
		Page:           uint(page),
		PerPage:        uint(perPage),
		OrderKey:       orderKey,
		OrderDirection: orderDirection,
		MatchQuery:     query,
		After:          afterString,
	}, nil
}

func hostListOptionsFromRequest(r *http.Request) (fleet.HostListOptions, error) {
	opt, err := listOptionsFromRequest(r)
	if err != nil {
		return fleet.HostListOptions{}, err
	}

	hopt := fleet.HostListOptions{ListOptions: opt}

	status := r.URL.Query().Get("status")
	switch fleet.HostStatus(status) {
	case fleet.StatusNew, fleet.StatusOnline, fleet.StatusOffline, fleet.StatusMIA, fleet.StatusMissing:
		hopt.StatusFilter = fleet.HostStatus(status)
	case "":
		// No error when unset
	default:
		return hopt, ctxerr.Wrap(r.Context(), badRequest(fmt.Sprintf("Invalid status: %s", status)))

	}

	additionalInfoFiltersString := r.URL.Query().Get("additional_info_filters")
	if additionalInfoFiltersString != "" {
		hopt.AdditionalFilters = strings.Split(additionalInfoFiltersString, ",")
	}

	teamID := r.URL.Query().Get("team_id")
	if teamID != "" {
		id, err := strconv.ParseUint(teamID, 10, 32)
		if err != nil {
			return hopt, ctxerr.Wrap(r.Context(), badRequest(fmt.Sprintf("Invalid team_id: %s", teamID)))
		}
		tid := uint(id)
		hopt.TeamFilter = &tid
	}

	policyID := r.URL.Query().Get("policy_id")
	if policyID != "" {
		id, err := strconv.ParseUint(policyID, 10, 32)
		if err != nil {
			return hopt, ctxerr.Wrap(r.Context(), badRequest(fmt.Sprintf("Invalid policy_id: %s", policyID)))
		}
		pid := uint(id)
		hopt.PolicyIDFilter = &pid
	}

	policyResponse := r.URL.Query().Get("policy_response")
	if policyResponse != "" {
		if hopt.PolicyIDFilter == nil {
			return hopt, ctxerr.Wrap(
				r.Context(), badRequest(
					"Missing policy_id (it must be present when policy_response is specified)",
				),
			)
		}
		var v *bool
		switch policyResponse {
		case "passing":
			v = ptr.Bool(true)
		case "failing":
			v = ptr.Bool(false)
		default:
			return hopt, ctxerr.Wrap(
				r.Context(),
				badRequest(
					fmt.Sprintf(
						"Invalid policy_response: %v (Valid options are 'passing' or 'failing')",
						policyResponse,
					),
				),
			)
		}
		hopt.PolicyResponseFilter = v
	}

	softwareID := r.URL.Query().Get("software_id")
	if softwareID != "" {
		id, err := strconv.ParseUint(softwareID, 10, 64)
		if err != nil {
			return hopt, ctxerr.Wrap(r.Context(), badRequest(fmt.Sprintf("Invalid software_id: %s", softwareID)))
		}
		sid := uint(id)
		hopt.SoftwareIDFilter = &sid
	}

	softwareVersionID := r.URL.Query().Get("software_version_id")
	if softwareVersionID != "" {
		id, err := strconv.ParseUint(softwareVersionID, 10, 64)
		if err != nil {
			return hopt, ctxerr.Wrap(r.Context(), badRequest(fmt.Sprintf("Invalid software_version_id: %s", softwareVersionID)))
		}
		sid := uint(id)
		hopt.SoftwareVersionIDFilter = &sid
	}

	softwareTitleID := r.URL.Query().Get("software_title_id")
	if softwareTitleID != "" {
		id, err := strconv.ParseUint(softwareTitleID, 10, 32)
		if err != nil {
			return hopt, ctxerr.Wrap(r.Context(), badRequest(fmt.Sprintf("Invalid software_title_id: %s", softwareTitleID)))
		}
		sid := uint(id)
		hopt.SoftwareTitleIDFilter = &sid
	}

	osID := r.URL.Query().Get("os_id")
	if osID != "" {
		id, err := strconv.ParseUint(osID, 10, 32)
		if err != nil {
			return hopt, ctxerr.Wrap(r.Context(), badRequest(fmt.Sprintf("Invalid os_id: %s", osID)))
		}
		sid := uint(id)
		hopt.OSIDFilter = &sid
	}

	osName := r.URL.Query().Get("os_name")
	if osName != "" {
		hopt.OSNameFilter = &osName
	}

	osVersion := r.URL.Query().Get("os_version")
	if osVersion != "" {
		hopt.OSVersionFilter = &osVersion
	}

	if hopt.OSNameFilter != nil && hopt.OSVersionFilter == nil {
		return hopt, ctxerr.Wrap(
			r.Context(), badRequest(
				"Invalid os_version (os_version must be specified with os_name)",
			),
		)
	}
	if hopt.OSNameFilter == nil && hopt.OSVersionFilter != nil {
		return hopt, ctxerr.Wrap(
			r.Context(), badRequest(
				"Invalid os_name (os_name must be specified with os_version)",
			),
		)
	}

	disableFailingPolicies := r.URL.Query().Get("disable_failing_policies")
	if disableFailingPolicies != "" {
		boolVal, err := strconv.ParseBool(disableFailingPolicies)
		if err != nil {
			return hopt, ctxerr.Wrap(
				r.Context(), badRequest(
					fmt.Sprintf(
						"Invalid disable_failing_policies: %s",
						disableFailingPolicies,
					),
				),
			)
		}
		hopt.DisableFailingPolicies = boolVal
	}

	deviceMapping := r.URL.Query().Get("device_mapping")
	if deviceMapping != "" {
		boolVal, err := strconv.ParseBool(deviceMapping)
		if err != nil {
			return hopt, ctxerr.Wrap(r.Context(), badRequest(fmt.Sprintf("Invalid device_mapping: %s", deviceMapping)))
		}
		hopt.DeviceMapping = boolVal
	}

	mdmID := r.URL.Query().Get("mdm_id")
	if mdmID != "" {
		id, err := strconv.ParseUint(mdmID, 10, 32)
		if err != nil {
			return hopt, ctxerr.Wrap(r.Context(), badRequest(fmt.Sprintf("Invalid mdm_id: %s", mdmID)))
		}
		mid := uint(id)
		hopt.MDMIDFilter = &mid
	}

	if mdmName := r.URL.Query().Get("mdm_name"); mdmName != "" {
		hopt.MDMNameFilter = &mdmName
	}

	enrollmentStatus := r.URL.Query().Get("mdm_enrollment_status")
	switch fleet.MDMEnrollStatus(enrollmentStatus) {
	case fleet.MDMEnrollStatusManual, fleet.MDMEnrollStatusAutomatic,
		fleet.MDMEnrollStatusPending, fleet.MDMEnrollStatusUnenrolled, fleet.MDMEnrollStatusEnrolled:
		hopt.MDMEnrollmentStatusFilter = fleet.MDMEnrollStatus(enrollmentStatus)
	case "":
		// No error when unset
	default:
		return hopt, ctxerr.Wrap(
			r.Context(), badRequest(fmt.Sprintf("Invalid mdm_enrollment_status: %s", enrollmentStatus)),
		)
	}

	macOSSettingsStatus := r.URL.Query().Get("macos_settings")
	switch fleet.OSSettingsStatus(macOSSettingsStatus) {
	case fleet.OSSettingsFailed, fleet.OSSettingsPending, fleet.OSSettingsVerifying, fleet.OSSettingsVerified:
		hopt.MacOSSettingsFilter = fleet.OSSettingsStatus(macOSSettingsStatus)
	case "":
		// No error when unset
	default:
		return hopt, ctxerr.Wrap(
			r.Context(), badRequest(fmt.Sprintf("Invalid macos_settings: %s", macOSSettingsStatus)),
		)
	}

	macOSSettingsDiskEncryptionStatus := r.URL.Query().Get("macos_settings_disk_encryption")
	switch fleet.DiskEncryptionStatus(macOSSettingsDiskEncryptionStatus) {
	case
		fleet.DiskEncryptionVerifying,
		fleet.DiskEncryptionVerified,
		fleet.DiskEncryptionActionRequired,
		fleet.DiskEncryptionEnforcing,
		fleet.DiskEncryptionFailed,
		fleet.DiskEncryptionRemovingEnforcement:
		hopt.MacOSSettingsDiskEncryptionFilter = fleet.DiskEncryptionStatus(macOSSettingsDiskEncryptionStatus)
	case "":
		// No error when unset
	default:
		return hopt, ctxerr.Wrap(
			r.Context(),
			badRequest(fmt.Sprintf("Invalid macos_settings_disk_encryption: %s", macOSSettingsDiskEncryptionStatus)),
		)
	}

	osSettingsStatus := r.URL.Query().Get("os_settings")
	switch fleet.OSSettingsStatus(osSettingsStatus) {
	case fleet.OSSettingsFailed, fleet.OSSettingsPending, fleet.OSSettingsVerifying, fleet.OSSettingsVerified:
		hopt.OSSettingsFilter = fleet.OSSettingsStatus(osSettingsStatus)
	case "":
		// No error when unset
	default:
		return hopt, ctxerr.Wrap(
			r.Context(), badRequest(fmt.Sprintf("Invalid os_settings: %s", osSettingsStatus)),
		)
	}

	osSettingsDiskEncryptionStatus := r.URL.Query().Get("os_settings_disk_encryption")
	switch fleet.DiskEncryptionStatus(osSettingsDiskEncryptionStatus) {
	case
		fleet.DiskEncryptionVerifying,
		fleet.DiskEncryptionVerified,
		fleet.DiskEncryptionActionRequired,
		fleet.DiskEncryptionEnforcing,
		fleet.DiskEncryptionFailed,
		fleet.DiskEncryptionRemovingEnforcement:
		hopt.OSSettingsDiskEncryptionFilter = fleet.DiskEncryptionStatus(osSettingsDiskEncryptionStatus)
	case "":
		// No error when unset
	default:
		return hopt, ctxerr.Wrap(
			r.Context(),
			badRequest(fmt.Sprintf("Invalid os_settings_disk_encryption: %s", macOSSettingsDiskEncryptionStatus)),
		)
	}

	mdmBootstrapPackageStatus := r.URL.Query().Get("bootstrap_package")
	switch fleet.MDMBootstrapPackageStatus(mdmBootstrapPackageStatus) {
	case fleet.MDMBootstrapPackageFailed, fleet.MDMBootstrapPackagePending, fleet.MDMBootstrapPackageInstalled:
		bpf := fleet.MDMBootstrapPackageStatus(mdmBootstrapPackageStatus)
		hopt.MDMBootstrapPackageFilter = &bpf
	case "":
		// No error when unset
	default:
		return hopt, ctxerr.Wrap(
			r.Context(), badRequest(fmt.Sprintf("Invalid bootstrap_package: %s", mdmBootstrapPackageStatus)),
		)
	}

	munkiIssueID := r.URL.Query().Get("munki_issue_id")
	if munkiIssueID != "" {
		id, err := strconv.ParseUint(munkiIssueID, 10, 32)
		if err != nil {
			return hopt, ctxerr.Wrap(r.Context(), badRequest(fmt.Sprintf("Invalid munki_issue_id: %s", munkiIssueID)))
		}
		mid := uint(id)
		hopt.MunkiIssueIDFilter = &mid
	}

	lowDiskSpace := r.URL.Query().Get("low_disk_space")
	if lowDiskSpace != "" {
		v, err := strconv.Atoi(lowDiskSpace)
		if err != nil {
			return hopt, ctxerr.Wrap(r.Context(), badRequest(fmt.Sprintf("Invalid low_disk_space: %s", lowDiskSpace)))
		}
		if v < 1 || v > 100 {
			return hopt, ctxerr.Wrap(
				r.Context(), badRequest(
					fmt.Sprintf(
						"Invalid low_disk_space, must be between 1 and 100: %s", lowDiskSpace,
					),
				),
			)
		}
		hopt.LowDiskSpaceFilter = &v
	}
	populateSoftware := r.URL.Query().Get("populate_software")
	if populateSoftware != "" {
		ps, err := strconv.ParseBool(populateSoftware)
		if err != nil {
			return hopt, ctxerr.Wrap(r.Context(), badRequest(fmt.Sprintf("Invalid populate_software: %s", populateSoftware)))
		}
		hopt.PopulateSoftware = ps
	}

	// cannot combine software_id, software_version_id, and software_title_id
	var softwareErrorLabel []string
	if hopt.SoftwareIDFilter != nil {
		softwareErrorLabel = append(softwareErrorLabel, "software_id")
	}
	if hopt.SoftwareVersionIDFilter != nil {
		softwareErrorLabel = append(softwareErrorLabel, "software_version_id")
	}
	if hopt.SoftwareTitleIDFilter != nil {
		softwareErrorLabel = append(softwareErrorLabel, "software_title_id")
	}
	if len(softwareErrorLabel) > 1 {
		return hopt, ctxerr.Wrap(r.Context(), badRequest(fmt.Sprintf("Invalid parameters. The combination of %s is not allowed.", strings.Join(softwareErrorLabel, " and "))))
	}

	return hopt, nil
}

func carveListOptionsFromRequest(r *http.Request) (fleet.CarveListOptions, error) {
	opt, err := listOptionsFromRequest(r)
	if err != nil {
		return fleet.CarveListOptions{}, err
	}

	carveOpts := fleet.CarveListOptions{ListOptions: opt}

	expired := r.URL.Query().Get("expired")
	if expired == "" {
		carveOpts.Expired = false
	} else {
		boolVal, err := strconv.ParseBool(expired)
		if err != nil {
			return carveOpts, ctxerr.Wrap(
				r.Context(), badRequest(
					fmt.Sprintf("Invalid expired: %s", expired),
				),
			)
		}
		carveOpts.Expired = boolVal
	}
	return carveOpts, nil
}

func userListOptionsFromRequest(r *http.Request) (fleet.UserListOptions, error) {
	opt, err := listOptionsFromRequest(r)
	if err != nil {
		return fleet.UserListOptions{}, err
	}

	userOpts := fleet.UserListOptions{ListOptions: opt}

	if tid := r.URL.Query().Get("team_id"); tid != "" {
		teamID, err := strconv.ParseUint(tid, 10, 64)
		if err != nil {
			return userOpts, ctxerr.Wrap(r.Context(), badRequest(fmt.Sprintf("Invalid team_id: %s", tid)))
		}
		// GitHub CodeQL flags this as: Incorrect conversion between integer types. Previously waived: https://github.com/fleetdm/fleet/security/code-scanning/516
		userOpts.TeamID = uint(teamID)
	}

	return userOpts, nil
}

type getGenericSpecRequest struct {
	Name string `url:"name"`
}