package gitlab

import (
	"context"
	"time"

	"github.com/xanzy/go-gitlab"
)

const defProjectsPerPage = 100

type Client struct {
	Ctx    context.Context
	gitlab *gitlab.Client
}

type Project struct {
	ID            int
	Description   string
	SSHURLToRepo  string
	HTTPURLToRepo string
	WebURL        string
	// Owner             User
	Name              string
	NameWithNamespace string
	Path              string
	PathWithNamespace string
	AvatarURL         string
	LastActivityAt    time.Time
}

type User struct {
	ID        int
	Username  string
	Email     string
	Name      string
	AvatarURL string
}

type ProgressInfo struct {
	ProgressChan chan Progress
	ProjectsChan chan []*Project
	ErrorChan    chan error
	DoneChan     chan interface{}
}

type Progress struct {
	Page          int
	Pages         int
	Projects      int
	TotalProjects int
}

// Given there may be thousands of projects, this will return
// channels that stream progress info and then finally the full
// list of projects on separate channels
func (c *Client) StreamProjects() *ProgressInfo {
	pi := &ProgressInfo{
		ProgressChan: make(chan Progress),
		ProjectsChan: make(chan []*Project),
		ErrorChan:    make(chan error),
		DoneChan:     make(chan interface{}),
	}

	go c.streamProjects(pi)

	return pi
}

func (c *Client) streamProjects(pi *ProgressInfo) {
	defer close(pi.ProgressChan)
	defer close(pi.ProjectsChan)

	listOpts := &gitlab.ListProjectsOptions{
		ListOptions: gitlab.ListOptions{
			PerPage: defProjectsPerPage,
			Page:    1,
		},
		Archived: new(bool),
	}

	var numProjects int
	for {
		projects, resp, err := c.ListProjects(listOpts)

		// We're done when we have it all or our context is done
		if c.Ctx.Err() != nil || resp.NextPage == 0 {
			pi.DoneChan <- nil
			break
		}

		if err != nil {
			pi.ErrorChan <- err
		}

		numProjects += len(projects)
		pi.ProjectsChan <- projects
		pi.ProgressChan <- Progress{
			Page:          resp.CurrentPage,
			Pages:         resp.TotalPages,
			Projects:      numProjects,
			TotalProjects: resp.TotalItems,
		}
		listOpts.Page = resp.NextPage
	}
}

// Returns a list of projects along with the next page and an error
// if there was an error
func (c *Client) ListProjects(opts *gitlab.ListProjectsOptions) (
	[]*Project, *gitlab.Response, error) {
	pList := make([]*Project, 0)
	projects, resp, err := c.gitlab.Projects.ListProjects(
		opts,
		gitlab.WithContext(c.Ctx),
	)
	if err == nil {
		pList = append(pList, c.handleProjects(projects)...)
	}
	return pList, resp, err
}

func (c *Client) handleProjects(projects []*gitlab.Project) []*Project {
	// Opportunity to perform any filtering or additional lookups
	// on a per-project basis
	pList := make([]*Project, 0, len(projects))
	for _, project := range projects {
		p := &Project{
			ID:                project.ID,
			Description:       project.Description,
			SSHURLToRepo:      project.SSHURLToRepo,
			HTTPURLToRepo:     project.HTTPURLToRepo,
			WebURL:            project.WebURL,
			Name:              project.Name,
			NameWithNamespace: project.NameWithNamespace,
			Path:              project.Path,
			PathWithNamespace: project.PathWithNamespace,
			LastActivityAt:    *project.LastActivityAt,
		}
		pList = append(pList, p)
	}
	return pList
}

func NewGitlabClient(ctx context.Context, host, token string) (*Client, error) {
	client, err := gitlab.NewClient(token, gitlab.WithBaseURL(host))
	if err != nil {
		return nil, err
	}
	gitlabClient := &Client{
		Ctx:    ctx,
		gitlab: client,
	}
	return gitlabClient, nil
}