package git

import (
	"context"
	"fmt"
	"github.com/xanzy/go-gitlab"
)

// GitLabProvider represents a GitLab API wrapper
type GitLabProvider struct {
	IsPrivate  bool
	IsPersonal bool
}

const (
	GitLabTokenName       = "GITLAB_TOKEN"
	GitLabDefaultHostname = "gitlab.com"
)

func (p *GitLabProvider) newClient(r *Repository) (*gitlab.Client, error) {
	gl, err := gitlab.NewClient(r.Token)
	if err != nil {
		return nil, err
	}

	if r.Host != GitLabDefaultHostname {
		gl, err = gitlab.NewClient(r.Token, gitlab.WithBaseURL(fmt.Sprintf("https://%s/api/v4", r.Host)))
		if err != nil {
			return nil, err
		}
	}
	return gl, nil
}

// CreateRepository returns false if the repository already exists
func (p *GitLabProvider) CreateRepository(ctx context.Context, r *Repository) (bool, error) {
	gl, err := p.newClient(r)
	if err != nil {
		return false, fmt.Errorf("client error: %w", err)
	}

	var id *int
	if !p.IsPersonal {
		groups, _, err := gl.Groups.ListGroups(&gitlab.ListGroupsOptions{Search: gitlab.String(r.Owner)}, gitlab.WithContext(ctx))
		if err != nil {
			return false, fmt.Errorf("list groups error: %w", err)
		}

		if len(groups) > 0 {
			id = &groups[0].ID
		}
	}

	visibility := gitlab.PublicVisibility
	if p.IsPrivate {
		visibility = gitlab.PrivateVisibility
	}

	projects, _, err := gl.Projects.ListProjects(&gitlab.ListProjectsOptions{Search: gitlab.String(r.Name)}, gitlab.WithContext(ctx))
	if err != nil {
		return false, fmt.Errorf("list projects error: %w", err)
	}

	if len(projects) == 0 {
		p := &gitlab.CreateProjectOptions{
			Name:                 gitlab.String(r.Name),
			NamespaceID:          id,
			Visibility:           &visibility,
			InitializeWithReadme: gitlab.Bool(true),
		}

		_, _, err := gl.Projects.CreateProject(p)
		if err != nil {
			return false, fmt.Errorf("create project error: %w", err)
		}
		return true, nil
	}

	return false, nil
}

// AddTeam returns false if the team is already assigned to the repository
func (p *GitLabProvider) AddTeam(ctx context.Context, r *Repository, name, permission string) (bool, error) {
	return false, nil
}

// AddDeployKey returns false if the key exists and the content is the same
func (p *GitLabProvider) AddDeployKey(ctx context.Context, r *Repository, key, keyName string) (bool, error) {
	gl, err := p.newClient(r)
	if err != nil {
		return false, fmt.Errorf("client error: %w", err)
	}

	// list deploy keys
	var projId int
	projects, _, err := gl.Projects.ListProjects(&gitlab.ListProjectsOptions{Search: gitlab.String(r.Name)}, gitlab.WithContext(ctx))
	if err != nil {
		return false, fmt.Errorf("list projects error: %w", err)
	}
	if len(projects) > 0 {
		projId = projects[0].ID
	} else {
		return false, fmt.Errorf("no project found")
	}

	// check if the key exists
	keys, _, err := gl.DeployKeys.ListProjectDeployKeys(projId, &gitlab.ListProjectDeployKeysOptions{})
	if err != nil {
		return false, fmt.Errorf("list keys error: %w", err)
	}

	shouldCreateKey := true
	var existingKey *gitlab.DeployKey
	for _, k := range keys {
		if k.Title == keyName {
			if k.Key != key {
				existingKey = k
			} else {
				shouldCreateKey = false
			}
			break
		}
	}

	// delete existing key if the value differs
	if existingKey != nil {
		_, err := gl.DeployKeys.DeleteDeployKey(projId, existingKey.ID, gitlab.WithContext(ctx))
		if err != nil {
			return false, fmt.Errorf("delete key error: %w", err)
		}
	}

	// create key
	if shouldCreateKey {
		_, _, err := gl.DeployKeys.AddDeployKey(projId, &gitlab.AddDeployKeyOptions{
			Title:   gitlab.String(keyName),
			Key:     gitlab.String(key),
			CanPush: gitlab.Bool(false),
		}, gitlab.WithContext(ctx))
		if err != nil {
			return false, fmt.Errorf("add key error: %w", err)
		}
		return true, nil
	}

	return false, nil
}