package list

import (
	"encoding/json"
	"fmt"
	"net/http"
	"regexp"
	"strings"
	"time"

	"github.com/MakeNowJust/heredoc"
	"github.com/cli/cli/v2/api"
	"github.com/cli/cli/v2/internal/config"
	"github.com/cli/cli/v2/internal/ghinstance"
	"github.com/cli/cli/v2/internal/ghrepo"
	"github.com/cli/cli/v2/internal/tableprinter"
	"github.com/cli/cli/v2/pkg/cmd/variable/shared"
	"github.com/cli/cli/v2/pkg/cmdutil"
	"github.com/cli/cli/v2/pkg/iostreams"
	"github.com/spf13/cobra"
)

type ListOptions struct {
	HttpClient func() (*http.Client, error)
	IO         *iostreams.IOStreams
	Config     func() (config.Config, error)
	BaseRepo   func() (ghrepo.Interface, error)

	OrgName     string
	EnvName     string
	Application string
}

func NewCmdList(f *cmdutil.Factory, runF func(*ListOptions) error) *cobra.Command {
	opts := &ListOptions{
		IO:         f.IOStreams,
		Config:     f.Config,
		HttpClient: f.HttpClient,
	}

	cmd := &cobra.Command{
		Use:   "list",
		Short: "List variables",
		Long: heredoc.Doc(`
			List variables on one of the following levels:
			- repository (default): available to Actions runs or Dependabot in a repository
			- environment: available to Actions runs for a deployment environment in a repository
			- organization: available to Actions runs or Dependabot within an organization
		`),
		Aliases: []string{"ls"},
		Args:    cobra.NoArgs,
		RunE: func(cmd *cobra.Command, args []string) error {
			// support `-R, --repo` override
			opts.BaseRepo = f.BaseRepo

			if err := cmdutil.MutuallyExclusive("specify only one of `--org` or `--env`", opts.OrgName != "", opts.EnvName != ""); err != nil {
				return err
			}

			if runF != nil {
				return runF(opts)
			}

			return listRun(opts)
		},
	}

	cmd.Flags().StringVarP(&opts.OrgName, "org", "o", "", "List variables for an organization")
	cmd.Flags().StringVarP(&opts.EnvName, "env", "e", "", "List variables for an environment")

	return cmd
}

func listRun(opts *ListOptions) error {
	client, err := opts.HttpClient()
	if err != nil {
		return fmt.Errorf("could not create http client: %w", err)
	}

	orgName := opts.OrgName
	envName := opts.EnvName

	var baseRepo ghrepo.Interface
	if orgName == "" {
		baseRepo, err = opts.BaseRepo()
		if err != nil {
			return err
		}
	}

	variableEntity, err := shared.GetVariableEntity(orgName, envName)
	if err != nil {
		return err
	}

	var variables []*Variable
	showSelectedRepoInfo := opts.IO.IsStdoutTTY()

	switch variableEntity {
	case shared.Repository:
		variables, err = getRepoVariables(client, baseRepo)
	case shared.Environment:
		variables, err = getEnvVariables(client, baseRepo, envName)
	case shared.Organization:
		var cfg config.Config
		var host string

		cfg, err = opts.Config()
		if err != nil {
			return err
		}

		host, _ = cfg.Authentication().DefaultHost()

		variables, err = getOrgVariables(client, host, orgName, showSelectedRepoInfo)
	}

	if err != nil {
		return fmt.Errorf("failed to get variables: %w", err)
	}

	if len(variables) == 0 {
		return cmdutil.NewNoResultsError("no variables found")
	}

	if err := opts.IO.StartPager(); err == nil {
		defer opts.IO.StopPager()
	} else {
		fmt.Fprintf(opts.IO.ErrOut, "failed to start pager: %v\n", err)
	}

	table := tableprinter.New(opts.IO)
	if opts.OrgName != "" {
		table.HeaderRow("NAME", "VALUE", "UPDATED AT", "VISIBILITY")
	} else {
		table.HeaderRow("NAME", "VALUE", "UPDATED AT")
	}
	for _, variable := range variables {
		table.AddField(variable.Name)
		table.AddField(variable.Value)
		updatedAt := variable.UpdatedAt.Format("2006-01-02")
		if opts.IO.IsStdoutTTY() {
			updatedAt = fmt.Sprintf("Updated %s", updatedAt)
		}
		table.AddField(updatedAt)
		if variable.Visibility != "" {
			if showSelectedRepoInfo {
				table.AddField(fmtVisibility(*variable))
			} else {
				table.AddField(strings.ToUpper(string(variable.Visibility)), nil, nil)
			}
		}
		table.EndRow()
	}

	err = table.Render()
	if err != nil {
		return err
	}

	return nil
}

type Variable struct {
	Name             string
	Value            string
	UpdatedAt        time.Time `json:"updated_at"`
	Visibility       shared.Visibility
	SelectedReposURL string `json:"selected_repositories_url"`
	NumSelectedRepos int
}

func fmtVisibility(s Variable) string {
	switch s.Visibility {
	case shared.All:
		return "Visible to all repositories"
	case shared.Private:
		return "Visible to private repositories"
	case shared.Selected:
		if s.NumSelectedRepos == 1 {
			return "Visible to 1 selected repository"
		} else {
			return fmt.Sprintf("Visible to %d selected repositories", s.NumSelectedRepos)
		}
	}
	return ""
}

func getOrgVariables(client httpClient, host, orgName string, showSelectedRepoInfo bool) ([]*Variable, error) {
	variables, err := getVariables(client, host, fmt.Sprintf("orgs/%s/actions/variables", orgName))
	if err != nil {
		return nil, err
	}

	if showSelectedRepoInfo {
		err = getSelectedRepositoryInformation(client, variables)
		if err != nil {
			return nil, err
		}
	}
	return variables, nil
}

func getEnvVariables(client httpClient, repo ghrepo.Interface, envName string) ([]*Variable, error) {
	path := fmt.Sprintf("repositories/%s/environments/%s/variables", ghrepo.FullName(repo), envName)
	return getVariables(client, repo.RepoHost(), path)
}

func getRepoVariables(client httpClient, repo ghrepo.Interface) ([]*Variable, error) {
	return getVariables(client, repo.RepoHost(), fmt.Sprintf("repos/%s/actions/variables",
		ghrepo.FullName(repo)))
}

type variablesPayload struct {
	Variables []*Variable
}

type httpClient interface {
	Do(*http.Request) (*http.Response, error)
}

func getVariables(client httpClient, host, path string) ([]*Variable, error) {
	var results []*Variable
	url := fmt.Sprintf("%s%s?per_page=100", ghinstance.RESTPrefix(host), path)

	for {
		var payload variablesPayload
		nextURL, err := apiGet(client, url, &payload)
		if err != nil {
			return nil, err
		}
		results = append(results, payload.Variables...)

		if nextURL == "" {
			break
		}
		url = nextURL
	}

	return results, nil
}

func apiGet(client httpClient, url string, data interface{}) (string, error) {
	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return "", err
	}
	req.Header.Set("Content-Type", "application/json; charset=utf-8")

	resp, err := client.Do(req)
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()

	if resp.StatusCode > 299 {
		return "", api.HandleHTTPError(resp)
	}

	dec := json.NewDecoder(resp.Body)
	if err := dec.Decode(data); err != nil {
		return "", err
	}

	return findNextPage(resp.Header.Get("Link")), nil
}

var linkRE = regexp.MustCompile(`<([^>]+)>;\s*rel="([^"]+)"`)

func findNextPage(link string) string {
	for _, m := range linkRE.FindAllStringSubmatch(link, -1) {
		if len(m) > 2 && m[2] == "next" {
			return m[1]
		}
	}
	return ""
}

func getSelectedRepositoryInformation(client httpClient, variables []*Variable) error {
	type responseData struct {
		TotalCount int `json:"total_count"`
	}

	for _, variable := range variables {
		if variable.SelectedReposURL == "" {
			continue
		}
		var result responseData
		if _, err := apiGet(client, variable.SelectedReposURL, &result); err != nil {
			return fmt.Errorf("failed determining selected repositories for %s: %w", variable.Name, err)
		}
		variable.NumSelectedRepos = result.TotalCount
	}

	return nil
}