/*
Copyright 2021 The Flux 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 bootstrap

import (
	"context"
	"errors"
	"fmt"
	"net/url"
	"strings"
	"time"

	corev1 "k8s.io/api/core/v1"
	"sigs.k8s.io/controller-runtime/pkg/client"

	"github.com/fluxcd/go-git-providers/gitprovider"

	"github.com/fluxcd/flux2/internal/bootstrap/git"
	"github.com/fluxcd/flux2/pkg/manifestgen/sourcesecret"
	"github.com/fluxcd/flux2/pkg/manifestgen/sync"
)

type GitProviderBootstrapper struct {
	*PlainGitBootstrapper

	owner      string
	repository string
	personal   bool

	description   string
	defaultBranch string
	visibility    string

	teams map[string]string

	readWriteKey bool

	bootstrapTransportType string
	syncTransportType      string

	sshHostname string

	provider gitprovider.Client
}

func NewGitProviderBootstrapper(git git.Git, provider gitprovider.Client, kube client.Client, opts ...GitProviderOption) (*GitProviderBootstrapper, error) {
	b := &GitProviderBootstrapper{
		PlainGitBootstrapper: &PlainGitBootstrapper{
			git:  git,
			kube: kube,
		},
		bootstrapTransportType: "https",
		syncTransportType:      "ssh",
		provider:               provider,
	}
	b.PlainGitBootstrapper.postGenerateSecret = append(b.PlainGitBootstrapper.postGenerateSecret, b.reconcileDeployKey)
	for _, opt := range opts {
		opt.applyGitProvider(b)
	}
	return b, nil
}

type GitProviderOption interface {
	applyGitProvider(b *GitProviderBootstrapper)
}

func WithProviderRepository(owner, repository string, personal bool) GitProviderOption {
	return providerRepositoryOption{
		owner:      owner,
		repository: repository,
		personal:   personal,
	}
}

type providerRepositoryOption struct {
	owner      string
	repository string
	personal   bool
}

func (o providerRepositoryOption) applyGitProvider(b *GitProviderBootstrapper) {
	b.owner = o.owner
	b.repository = o.repository
	b.personal = o.personal
}

func WithProviderRepositoryConfig(description, defaultBranch, visibility string) GitProviderOption {
	return providerRepositoryConfigOption{
		description:   description,
		defaultBranch: defaultBranch,
		visibility:    visibility,
	}
}

type providerRepositoryConfigOption struct {
	description   string
	defaultBranch string
	visibility    string
}

func (o providerRepositoryConfigOption) applyGitProvider(b *GitProviderBootstrapper) {
	b.description = o.description
	b.defaultBranch = o.defaultBranch
	b.visibility = o.visibility
}

func WithProviderTeamPermissions(teams map[string]string) GitProviderOption {
	return providerRepositoryTeamPermissionsOption(teams)
}

type providerRepositoryTeamPermissionsOption map[string]string

func (o providerRepositoryTeamPermissionsOption) applyGitProvider(b *GitProviderBootstrapper) {
	b.teams = o
}

func WithReadWriteKeyPermissions(b bool) GitProviderOption {
	return withReadWriteKeyPermissionsOption(b)
}

type withReadWriteKeyPermissionsOption bool

func (o withReadWriteKeyPermissionsOption) applyGitProvider(b *GitProviderBootstrapper) {
	b.readWriteKey = bool(o)
}

func WithBootstrapTransportType(protocol string) GitProviderOption {
	return bootstrapTransportTypeOption(protocol)
}

type bootstrapTransportTypeOption string

func (o bootstrapTransportTypeOption) applyGitProvider(b *GitProviderBootstrapper) {
	b.bootstrapTransportType = string(o)
}

func WithSyncTransportType(protocol string) GitProviderOption {
	return syncProtocolOption(protocol)
}

type syncProtocolOption string

func (o syncProtocolOption) applyGitProvider(b *GitProviderBootstrapper) {
	b.syncTransportType = string(o)
}

func WithSSHHostname(hostname string) GitProviderOption {
	return sshHostnameOption(hostname)
}

type sshHostnameOption string

func (o sshHostnameOption) applyGitProvider(b *GitProviderBootstrapper) {
	b.sshHostname = string(o)
}

func (b *GitProviderBootstrapper) ReconcileSyncConfig(ctx context.Context, options sync.Options, pollInterval, timeout time.Duration) error {
	repo, err := b.getRepository(ctx)
	if err != nil {
		return err
	}
	if b.url == "" {
		bootstrapURL, err := b.getCloneURL(repo, gitprovider.TransportType(b.bootstrapTransportType))
		if err != nil {
			return err
		}
		WithRepositoryURL(bootstrapURL).applyGit(b.PlainGitBootstrapper)
	}
	if options.URL == "" {
		syncURL, err := b.getCloneURL(repo, gitprovider.TransportType(b.syncTransportType))
		if err != nil {
			return err
		}
		options.URL = syncURL
	}
	return b.PlainGitBootstrapper.ReconcileSyncConfig(ctx, options, pollInterval, timeout)
}

// ReconcileRepository reconciles an organization or user repository with the
// GitProviderBootstrapper configuration. On success, the URL in the embedded
// PlainGitBootstrapper is set to clone URL for the configured protocol.
//
// When part of the reconciliation fails with a warning without aborting, an
// ErrReconciledWithWarning error is returned.
func (b *GitProviderBootstrapper) ReconcileRepository(ctx context.Context) error {
	var repo gitprovider.UserRepository
	var err error

	if b.personal {
		repo, err = b.reconcileUserRepository(ctx)
	} else {
		repo, err = b.reconcileOrgRepository(ctx)
	}
	if err != nil && !errors.Is(err, ErrReconciledWithWarning) {
		return err
	}

	cloneURL := repo.Repository().GetCloneURL(gitprovider.TransportType(b.bootstrapTransportType))
	// TODO(hidde): https://github.com/fluxcd/go-git-providers/issues/55
	if strings.HasPrefix(cloneURL, "https://https://") {
		cloneURL = strings.TrimPrefix(cloneURL, "https://")
	}
	WithRepositoryURL(cloneURL).applyGit(b.PlainGitBootstrapper)

	return err
}

func (b *GitProviderBootstrapper) reconcileDeployKey(ctx context.Context, secret corev1.Secret, options sourcesecret.Options) error {
	ppk, ok := secret.StringData[sourcesecret.PublicKeySecretKey]
	if !ok {
		return nil
	}
	b.logger.Successf("public key: %s", strings.TrimSpace(ppk))

	repo, err := b.getRepository(ctx)
	if err != nil {
		return err
	}

	name := deployKeyName(options.Namespace, b.branch, options.Name, options.TargetPath)
	deployKeyInfo := newDeployKeyInfo(name, ppk, b.readWriteKey)
	var changed bool
	if _, changed, err = repo.DeployKeys().Reconcile(ctx, deployKeyInfo); err != nil {
		return err
	}
	if changed {
		b.logger.Successf("configured deploy key %q for %q", deployKeyInfo.Name, repo.Repository().String())
	}
	return nil
}

// reconcileOrgRepository reconciles a gitprovider.OrgRepository
// with the GitProviderBootstrapper values, including any
// gitprovider.TeamAccessInfo configurations.
//
// If one of the gitprovider.TeamAccessInfo does not reconcile
// successfully, the gitprovider.UserRepository and an
// ErrReconciledWithWarning error are returned.
func (b *GitProviderBootstrapper) reconcileOrgRepository(ctx context.Context) (gitprovider.UserRepository, error) {
	b.logger.Actionf("connecting to %s", b.provider.SupportedDomain())

	// Construct the repository and other configuration objects
	// go-git-provider likes to work with
	subOrgs, repoName := splitSubOrganizationsFromRepositoryName(b.repository)
	orgRef := newOrganizationRef(b.provider.SupportedDomain(), b.owner, subOrgs)
	repoRef := newOrgRepositoryRef(orgRef, repoName)
	repoInfo := newRepositoryInfo(b.description, b.defaultBranch, b.visibility)

	// Reconcile the organization repository
	repo, err := b.provider.OrgRepositories().Get(ctx, repoRef)
	if err != nil {
		if !errors.Is(err, gitprovider.ErrNotFound) {
			return nil, fmt.Errorf("failed to get Git repository %q: %w", repoRef.String(), err)
		}
		// go-git-providers has at present some issues with the idempotency
		// of the available Reconcile methods, and setting e.g. the default
		// branch correctly. Resort to Create with AutoInit until this has
		// been resolved.
		repo, err = b.provider.OrgRepositories().Create(ctx, repoRef, repoInfo, &gitprovider.RepositoryCreateOptions{
			AutoInit: gitprovider.BoolVar(true),
		})
		if err != nil {
			return nil, fmt.Errorf("failed to create new Git repository %q: %w", repoRef.String(), err)
		}
		b.logger.Successf("repository %q created", repoRef.String())
	}

	// Set default branch before calling Reconcile due to bug described
	// above.
	repoInfo.DefaultBranch = repo.Get().DefaultBranch
	var changed bool
	if err = retry(1, 2*time.Second, func() (err error) {
		repo, changed, err = b.provider.OrgRepositories().Reconcile(ctx, repoRef, repoInfo)
		return
	}); err != nil {
		return nil, fmt.Errorf("failed to reconcile Git repository %q: %w", repoRef.String(), err)
	}
	if changed {
		b.logger.Successf("repository %q reconciled", repoRef.String())
	}

	// Build the team access config
	teamAccessInfo, err := buildTeamAccessInfo(b.teams, gitprovider.RepositoryPermissionVar(gitprovider.RepositoryPermissionMaintain))
	if err != nil {
		return nil, fmt.Errorf("failed to reconcile repository team access: %w", err)
	}

	// Reconcile the team access config on best effort (that being:
	// record the error as a warning, but continue with the
	// reconciliation of the others)
	var warning error
	if count := len(teamAccessInfo); count > 0 {
		b.logger.Actionf("reconciling repository permissions")
		for _, i := range teamAccessInfo {
			var err error
			_, changed, err = repo.TeamAccess().Reconcile(ctx, i)
			if err != nil {
				warning = fmt.Errorf("failed to grant permissions to team: %w", ErrReconciledWithWarning)
				b.logger.Failuref("failed to grant %q permissions to %q: %w", *i.Permission, i.Name, err)
			}
			if changed {
				b.logger.Successf("granted %q permissions to %q", *i.Permission, i.Name)
			}
		}
		b.logger.Successf("reconciled repository permissions")
	}
	return repo, warning
}

// reconcileUserRepository reconciles a gitprovider.UserRepository
// with the GitProviderBootstrapper values. It returns the reconciled
// gitprovider.UserRepository, or an error.
func (b *GitProviderBootstrapper) reconcileUserRepository(ctx context.Context) (gitprovider.UserRepository, error) {
	b.logger.Actionf("connecting to %s", b.provider.SupportedDomain())

	// Construct the repository and other metadata objects
	// go-git-provider likes to work with.
	_, repoName := splitSubOrganizationsFromRepositoryName(b.repository)
	userRef := newUserRef(b.provider.SupportedDomain(), b.owner)
	repoRef := newUserRepositoryRef(userRef, repoName)
	repoInfo := newRepositoryInfo(b.description, b.defaultBranch, b.visibility)

	repo, err := b.provider.UserRepositories().Get(ctx, repoRef)
	if err != nil {
		if !errors.Is(err, gitprovider.ErrNotFound) {
			return nil, fmt.Errorf("failed to get Git repository %q: %w", repoRef.String(), err)
		}
		// go-git-providers has at present some issues with the idempotency
		// of the available Reconcile methods, and setting e.g. the default
		// branch correctly. Resort to Create with AutoInit until this has
		// been resolved.
		repo, err = b.provider.UserRepositories().Create(ctx, repoRef, repoInfo, &gitprovider.RepositoryCreateOptions{
			AutoInit: gitprovider.BoolVar(true),
		})
		if err != nil {
			return nil, fmt.Errorf("failed to create new Git repository %q: %w", repoRef.String(), err)
		}
		b.logger.Successf("repository %q created", repoRef.String())
	}

	// Set default branch before calling Reconcile due to bug described
	// above.
	repoInfo.DefaultBranch = repo.Get().DefaultBranch
	var changed bool
	if err = retry(1, 2*time.Second, func() (err error) {
		repo, changed, err = b.provider.UserRepositories().Reconcile(ctx, repoRef, repoInfo)
		return
	}); err != nil {
		return nil, fmt.Errorf("failed to reconcile Git repository %q: %w", repoRef.String(), err)
	}
	if changed {
		b.logger.Successf("repository %q reconciled", repoRef.String())
	}

	return repo, nil
}

// getRepository retrieves and returns the gitprovider.UserRepository
// for organization and user repositories using the
// GitProviderBootstrapper values.
// As gitprovider.OrgRepository is a superset of gitprovider.UserRepository, this
// type is returned.
func (b *GitProviderBootstrapper) getRepository(ctx context.Context) (gitprovider.UserRepository, error) {
	subOrgs, repoName := splitSubOrganizationsFromRepositoryName(b.repository)

	if b.personal {
		userRef := newUserRef(b.provider.SupportedDomain(), b.owner)
		return b.provider.UserRepositories().Get(ctx, newUserRepositoryRef(userRef, repoName))
	}

	orgRef := newOrganizationRef(b.provider.SupportedDomain(), b.owner, subOrgs)
	return b.provider.OrgRepositories().Get(ctx, newOrgRepositoryRef(orgRef, repoName))
}

// getCloneURL returns the Git clone URL for the given
// gitprovider.UserRepository. If the given transport type is
// gitprovider.TransportTypeSSH and a custom SSH hostname is configured,
// the hostname of the URL will be modified to this hostname.
func (b *GitProviderBootstrapper) getCloneURL(repository gitprovider.UserRepository, transport gitprovider.TransportType) (string, error) {
	u := repository.Repository().GetCloneURL(transport)
	// TODO(hidde): https://github.com/fluxcd/go-git-providers/issues/55
	if strings.HasPrefix(u, "https://https://") {
		u = strings.TrimPrefix(u, "https://")
	}
	var err error
	if transport == gitprovider.TransportTypeSSH && b.sshHostname != "" {
		if u, err = setHostname(u, b.sshHostname); err != nil {
			err = fmt.Errorf("failed to set SSH hostname for URL %q: %w", u, err)
		}
	}
	return u, err
}

// splitSubOrganizationsFromRepositoryName removes any prefixed sub
// organizations from the given repository name by splitting the
// string into a slice by '/'.
// The last (or only) item of the slice result is assumed to be the
// repository name, other items (nested) sub organizations.
func splitSubOrganizationsFromRepositoryName(name string) ([]string, string) {
	elements := strings.Split(name, "/")
	i := len(elements)
	switch i {
	case 1:
		return nil, name
	default:
		return elements[:i-1], elements[i-1]
	}
}

// buildTeamAccessInfo constructs a gitprovider.TeamAccessInfo slice
// from the given string map of team names to permissions.
//
// Providing a default gitprovider.RepositoryPermission is optional,
// and omitting it will make it default to the go-git-provider default.
//
// An error is returned if any of the given permissions is invalid.
func buildTeamAccessInfo(m map[string]string, defaultPermissions *gitprovider.RepositoryPermission) ([]gitprovider.TeamAccessInfo, error) {
	var infos []gitprovider.TeamAccessInfo
	if defaultPermissions != nil {
		if err := gitprovider.ValidateRepositoryPermission(*defaultPermissions); err != nil {
			return nil, fmt.Errorf("invalid default team permission %q", *defaultPermissions)
		}
	}
	for n, p := range m {
		permission := defaultPermissions
		if p != "" {
			p := gitprovider.RepositoryPermission(p)
			if err := gitprovider.ValidateRepositoryPermission(p); err != nil {
				return nil, fmt.Errorf("invalid permission %q for team %q", p, n)
			}
			permission = &p
		}
		i := gitprovider.TeamAccessInfo{
			Name:       n,
			Permission: permission,
		}
		infos = append(infos, i)
	}
	return infos, nil
}

// newOrganizationRef constructs a gitprovider.OrganizationRef with the
// given values and returns the result.
func newOrganizationRef(domain, organization string, subOrganizations []string) gitprovider.OrganizationRef {
	return gitprovider.OrganizationRef{
		Domain:           domain,
		Organization:     organization,
		SubOrganizations: subOrganizations,
	}
}

// newOrgRepositoryRef constructs a gitprovider.OrgRepositoryRef with
// the given values and returns the result.
func newOrgRepositoryRef(organizationRef gitprovider.OrganizationRef, name string) gitprovider.OrgRepositoryRef {
	return gitprovider.OrgRepositoryRef{
		OrganizationRef: organizationRef,
		RepositoryName:  name,
	}
}

// newUserRef constructs a gitprovider.UserRef with the given values
// and returns the result.
func newUserRef(domain, login string) gitprovider.UserRef {
	return gitprovider.UserRef{
		Domain:    domain,
		UserLogin: login,
	}
}

// newUserRepositoryRef constructs a gitprovider.UserRepositoryRef with
// the given values and returns the result.
func newUserRepositoryRef(userRef gitprovider.UserRef, name string) gitprovider.UserRepositoryRef {
	return gitprovider.UserRepositoryRef{
		UserRef:        userRef,
		RepositoryName: name,
	}
}

// newRepositoryInfo constructs a gitprovider.RepositoryInfo with the
// given values and returns the result.
func newRepositoryInfo(description, defaultBranch, visibility string) gitprovider.RepositoryInfo {
	var i gitprovider.RepositoryInfo
	if description != "" {
		i.Description = gitprovider.StringVar(description)
	}
	if defaultBranch != "" {
		i.DefaultBranch = gitprovider.StringVar(defaultBranch)
	}
	if visibility != "" {
		i.Visibility = gitprovider.RepositoryVisibilityVar(gitprovider.RepositoryVisibility(visibility))
	}
	return i
}

// newDeployKeyInfo constructs a gitprovider.DeployKeyInfo with the
// given values and returns the result.
func newDeployKeyInfo(name, publicKey string, readWrite bool) gitprovider.DeployKeyInfo {
	keyInfo := gitprovider.DeployKeyInfo{
		Name: name,
		Key:  []byte(publicKey),
	}
	if readWrite {
		keyInfo.ReadOnly = gitprovider.BoolVar(false)
	}
	return keyInfo
}

func deployKeyName(namespace, secretName, branch, path string) string {
	var name string
	for _, v := range []string{namespace, secretName, branch, path} {
		if v == "" {
			continue
		}
		if name == "" {
			name = v
		} else {
			name = name + "-" + v
		}
	}
	return name
}

// setHostname is a helper to replace the hostname of the given URL.
// TODO(hidde): support for this should be added in go-git-providers.
func setHostname(URL, hostname string) (string, error) {
	u, err := url.Parse(URL)
	if err != nil {
		return URL, err
	}
	u.Host = hostname
	return u.String(), nil
}