// SPDX-FileCopyrightText: 2024 Dan Anglin <d.n.i.anglin@gmail.com>
//
// SPDX-License-Identifier: GPL-3.0-or-later

package executor

import (
	"errors"
	"flag"
	"fmt"
	"path/filepath"
	"strings"

	"codeflow.dananglin.me.uk/apollo/enbas/internal/client"
	"codeflow.dananglin.me.uk/apollo/enbas/internal/model"
	"codeflow.dananglin.me.uk/apollo/enbas/internal/printer"
	"codeflow.dananglin.me.uk/apollo/enbas/internal/utilities"
)

type ShowExecutor struct {
	*flag.FlagSet

	printer                 *printer.Printer
	myAccount               bool
	skipAccountRelationship bool
	showUserPreferences     bool
	showInBrowser           bool
	configDir               string
	cacheRoot               string
	resourceType            string
	accountName             string
	statusID                string
	timelineCategory        string
	listID                  string
	tag                     string
	pollID                  string
	attachmentID            string
	fromResourceType        string
	limit                   int
}

func NewShowExecutor(printer *printer.Printer, configDir, cacheRoot, name, summary string) *ShowExecutor {
	showExe := ShowExecutor{
		FlagSet: flag.NewFlagSet(name, flag.ExitOnError),

		printer:   printer,
		configDir: configDir,
		cacheRoot: cacheRoot,
	}

	showExe.BoolVar(&showExe.myAccount, flagMyAccount, false, "Set to true to lookup your account")
	showExe.BoolVar(&showExe.skipAccountRelationship, flagSkipRelationship, false, "Set to true to skip showing your relationship to the specified account")
	showExe.BoolVar(&showExe.showUserPreferences, flagShowPreferences, false, "Show your preferences")
	showExe.BoolVar(&showExe.showInBrowser, flagBrowser, false, "Set to true to view in the browser")
	showExe.StringVar(&showExe.resourceType, flagType, "", "Specify the type of resource to display")
	showExe.StringVar(&showExe.accountName, flagAccountName, "", "Specify the account name in full (username@domain)")
	showExe.StringVar(&showExe.statusID, flagStatusID, "", "Specify the ID of the status to display")
	showExe.StringVar(&showExe.timelineCategory, flagTimelineCategory, model.TimelineCategoryHome, "Specify the timeline category to view")
	showExe.StringVar(&showExe.listID, flagListID, "", "Specify the ID of the list to display")
	showExe.StringVar(&showExe.tag, flagTag, "", "Specify the name of the tag to use")
	showExe.StringVar(&showExe.pollID, flagPollID, "", "Specify the ID of the poll to display")
	showExe.StringVar(&showExe.attachmentID, flagAttachmentID, "", "Specify the ID of the media attachment to display")
	showExe.StringVar(&showExe.fromResourceType, flagFrom, "", "Specify the resource type to view the target resource from (e.g. status for viewing media from, etc)")
	showExe.IntVar(&showExe.limit, flagLimit, 20, "Specify the limit of items to display")

	showExe.Usage = commandUsageFunc(name, summary, showExe.FlagSet)

	return &showExe
}

func (s *ShowExecutor) Execute() error {
	if s.resourceType == "" {
		return FlagNotSetError{flagText: flagType}
	}

	funcMap := map[string]func(*client.Client) error{
		resourceInstance:        s.showInstance,
		resourceAccount:         s.showAccount,
		resourceStatus:          s.showStatus,
		resourceTimeline:        s.showTimeline,
		resourceList:            s.showList,
		resourceFollowers:       s.showFollowers,
		resourceFollowing:       s.showFollowing,
		resourceBlocked:         s.showBlocked,
		resourceBookmarks:       s.showBookmarks,
		resourceLiked:           s.showLiked,
		resourceStarred:         s.showLiked,
		resourceFollowRequest:   s.showFollowRequests,
		resourcePoll:            s.showPoll,
		resourceMutedAccounts:   s.showMutedAccounts,
		resourceMedia:           s.showMedia,
		resourceMediaAttachment: s.showMediaAttachment,
	}

	doFunc, ok := funcMap[s.resourceType]
	if !ok {
		return UnsupportedTypeError{resourceType: s.resourceType}
	}

	gtsClient, err := client.NewClientFromConfig(s.configDir)
	if err != nil {
		return fmt.Errorf("unable to create the GoToSocial client: %w", err)
	}

	return doFunc(gtsClient)
}

func (s *ShowExecutor) showInstance(gtsClient *client.Client) error {
	instance, err := gtsClient.GetInstance()
	if err != nil {
		return fmt.Errorf("unable to retrieve the instance details: %w", err)
	}

	s.printer.PrintInstance(instance)

	return nil
}

func (s *ShowExecutor) showAccount(gtsClient *client.Client) error {
	var (
		account model.Account
		err     error
	)

	if s.myAccount {
		account, err = getMyAccount(gtsClient, s.configDir)
		if err != nil {
			return fmt.Errorf("received an error while getting the account details: %w", err)
		}
	} else {
		if s.accountName == "" {
			return FlagNotSetError{flagText: flagAccountName}
		}

		account, err = getAccount(gtsClient, s.accountName)
		if err != nil {
			return fmt.Errorf("received an error while getting the account details: %w", err)
		}
	}

	if s.showInBrowser {
		utilities.OpenLink(account.URL)

		return nil
	}

	var (
		relationship *model.AccountRelationship
		preferences  *model.Preferences
	)

	if !s.myAccount && !s.skipAccountRelationship {
		relationship, err = gtsClient.GetAccountRelationship(account.ID)
		if err != nil {
			return fmt.Errorf("unable to retrieve the relationship to this account: %w", err)
		}
	}

	if s.myAccount && s.showUserPreferences {
		preferences, err = gtsClient.GetUserPreferences()
		if err != nil {
			return fmt.Errorf("unable to retrieve the user preferences: %w", err)
		}
	}

	s.printer.PrintAccount(account, relationship, preferences)

	return nil
}

func (s *ShowExecutor) showStatus(gtsClient *client.Client) error {
	if s.statusID == "" {
		return FlagNotSetError{flagText: flagStatusID}
	}

	status, err := gtsClient.GetStatus(s.statusID)
	if err != nil {
		return fmt.Errorf("unable to retrieve the status: %w", err)
	}

	if s.showInBrowser {
		utilities.OpenLink(status.URL)

		return nil
	}

	s.printer.PrintStatus(status)

	return nil
}

func (s *ShowExecutor) showTimeline(gtsClient *client.Client) error {
	var (
		timeline model.StatusList
		err      error
	)

	switch s.timelineCategory {
	case model.TimelineCategoryHome:
		timeline, err = gtsClient.GetHomeTimeline(s.limit)
	case model.TimelineCategoryPublic:
		timeline, err = gtsClient.GetPublicTimeline(s.limit)
	case model.TimelineCategoryList:
		if s.listID == "" {
			return FlagNotSetError{flagText: flagListID}
		}

		var list model.List

		list, err = gtsClient.GetList(s.listID)
		if err != nil {
			return fmt.Errorf("unable to retrieve the list: %w", err)
		}

		timeline, err = gtsClient.GetListTimeline(list.ID, list.Title, s.limit)
	case model.TimelineCategoryTag:
		if s.tag == "" {
			return FlagNotSetError{flagText: flagTag}
		}

		timeline, err = gtsClient.GetTagTimeline(s.tag, s.limit)
	default:
		return model.InvalidTimelineCategoryError{Value: s.timelineCategory}
	}

	if err != nil {
		return fmt.Errorf("unable to retrieve the %s timeline: %w", s.timelineCategory, err)
	}

	if len(timeline.Statuses) == 0 {
		s.printer.PrintInfo("There are no statuses in this timeline.\n")

		return nil
	}

	s.printer.PrintStatusList(timeline)

	return nil
}

func (s *ShowExecutor) showList(gtsClient *client.Client) error {
	if s.listID == "" {
		return s.showLists(gtsClient)
	}

	list, err := gtsClient.GetList(s.listID)
	if err != nil {
		return fmt.Errorf("unable to retrieve the list: %w", err)
	}

	accounts, err := gtsClient.GetAccountsFromList(s.listID, 0)
	if err != nil {
		return fmt.Errorf("unable to retrieve the accounts from the list: %w", err)
	}

	if len(accounts) > 0 {
		accountMap := make(map[string]string)
		for i := range accounts {
			accountMap[accounts[i].Acct] = accounts[i].Username
		}

		list.Accounts = accountMap
	}

	s.printer.PrintList(list)

	return nil
}

func (s *ShowExecutor) showLists(gtsClient *client.Client) error {
	lists, err := gtsClient.GetAllLists()
	if err != nil {
		return fmt.Errorf("unable to retrieve the lists: %w", err)
	}

	if len(lists) == 0 {
		s.printer.PrintInfo("You have no lists.\n")

		return nil
	}

	s.printer.PrintLists(lists)

	return nil
}

func (s *ShowExecutor) showFollowers(gtsClient *client.Client) error {
	accountID, err := getAccountID(gtsClient, s.myAccount, s.accountName, s.configDir)
	if err != nil {
		return fmt.Errorf("received an error while getting the account ID: %w", err)
	}

	followers, err := gtsClient.GetFollowers(accountID, s.limit)
	if err != nil {
		return fmt.Errorf("unable to retrieve the list of followers: %w", err)
	}

	if len(followers.Accounts) > 0 {
		s.printer.PrintAccountList(followers)
	} else {
		s.printer.PrintInfo("There are no followers for this account (or the list is hidden).\n")
	}

	return nil
}

func (s *ShowExecutor) showFollowing(gtsClient *client.Client) error {
	accountID, err := getAccountID(gtsClient, s.myAccount, s.accountName, s.configDir)
	if err != nil {
		return fmt.Errorf("received an error while getting the account ID: %w", err)
	}

	following, err := gtsClient.GetFollowing(accountID, s.limit)
	if err != nil {
		return fmt.Errorf("unable to retrieve the list of followed accounts: %w", err)
	}

	if len(following.Accounts) > 0 {
		s.printer.PrintAccountList(following)
	} else {
		s.printer.PrintInfo("This account is not following anyone or the list is hidden.\n")
	}

	return nil
}

func (s *ShowExecutor) showBlocked(gtsClient *client.Client) error {
	blocked, err := gtsClient.GetBlockedAccounts(s.limit)
	if err != nil {
		return fmt.Errorf("unable to retrieve the list of blocked accounts: %w", err)
	}

	if len(blocked.Accounts) > 0 {
		s.printer.PrintAccountList(blocked)
	} else {
		s.printer.PrintInfo("You have no blocked accounts.\n")
	}

	return nil
}

func (s *ShowExecutor) showBookmarks(gtsClient *client.Client) error {
	bookmarks, err := gtsClient.GetBookmarks(s.limit)
	if err != nil {
		return fmt.Errorf("unable to retrieve the list of bookmarks: %w", err)
	}

	if len(bookmarks.Statuses) > 0 {
		s.printer.PrintStatusList(bookmarks)
	} else {
		s.printer.PrintInfo("You have no bookmarks.\n")
	}

	return nil
}

func (s *ShowExecutor) showLiked(gtsClient *client.Client) error {
	liked, err := gtsClient.GetLikedStatuses(s.limit, s.resourceType)
	if err != nil {
		return fmt.Errorf("unable to retrieve the list of your %s statuses: %w", s.resourceType, err)
	}

	if len(liked.Statuses) > 0 {
		s.printer.PrintStatusList(liked)
	} else {
		s.printer.PrintInfo("You have no " + s.resourceType + " statuses.\n")
	}

	return nil
}

func (s *ShowExecutor) showFollowRequests(gtsClient *client.Client) error {
	accounts, err := gtsClient.GetFollowRequests(s.limit)
	if err != nil {
		return fmt.Errorf("unable to retrieve the list of follow requests: %w", err)
	}

	if len(accounts.Accounts) > 0 {
		s.printer.PrintAccountList(accounts)
	} else {
		s.printer.PrintInfo("You have no follow requests.\n")
	}

	return nil
}

func (s *ShowExecutor) showPoll(gtsClient *client.Client) error {
	if s.pollID == "" {
		return FlagNotSetError{flagText: flagPollID}
	}

	poll, err := gtsClient.GetPoll(s.pollID)
	if err != nil {
		return fmt.Errorf("unable to retrieve the poll: %w", err)
	}

	s.printer.PrintPoll(poll)

	return nil
}

func (s *ShowExecutor) showMutedAccounts(gtsClient *client.Client) error {
	muted, err := gtsClient.GetMutedAccounts(s.limit)
	if err != nil {
		return fmt.Errorf("unable to retrieve the list of muted accounts: %w", err)
	}

	if len(muted.Accounts) > 0 {
		s.printer.PrintAccountList(muted)
	} else {
		s.printer.PrintInfo("You have not muted any accounts.\n")
	}

	return nil
}

func (s *ShowExecutor) showMediaAttachment(gtsClient *client.Client) error {
	if s.attachmentID == "" {
		return FlagNotSetError{flagText: flagAttachmentID}
	}

	attachment, err := gtsClient.GetMediaAttachment(s.attachmentID)
	if err != nil {
		return fmt.Errorf("unable to retrieve the media attachment: %w", err)
	}

	s.printer.PrintMediaAttachment(attachment)

	return nil
}

func (s *ShowExecutor) showMedia(gtsClient *client.Client) error {
	if s.fromResourceType == "" {
		return FlagNotSetError{flagText: flagFrom}
	}

	funcMap := map[string]func(*client.Client) error{
		resourceStatus: s.showMediaFromStatus,
	}

	doFunc, ok := funcMap[s.fromResourceType]
	if !ok {
		return fmt.Errorf("do not support viewing media from %s", s.fromResourceType)
	}

	return doFunc(gtsClient)
}

func (s *ShowExecutor) showMediaFromStatus(gtsClient *client.Client) error {
	if s.attachmentID == "" {
		return FlagNotSetError{flagText: flagAttachmentID}
	}

	if s.statusID == "" {
		return FlagNotSetError{flagText: flagStatusID}
	}

	status, err := gtsClient.GetStatus(s.statusID)
	if err != nil {
		return fmt.Errorf("unable to retrieve the status: %w", err)
	}

	attachmentExists := false
	mediaURL := ""
	mediaFilename := ""

	for _, attachment := range status.MediaAttachments {
		if attachment.ID == s.attachmentID {
			mediaURL = attachment.URL
			split := strings.Split(attachment.URL, "/")
			mediaFilename = split[len(split)-1]
			attachmentExists = true

			break
		}
	}

	if !attachmentExists {
		return errors.New("this media is not attached to this status")
	}

	cacheDir := filepath.Join(
		utilities.CalculateCacheDir(s.cacheRoot, utilities.GetFQDN(gtsClient.Authentication.Instance)),
		"media",
	)

	if err := utilities.EnsureDirectory(cacheDir); err != nil {
		return fmt.Errorf("unable to ensure the existence of the directory %q: %w", cacheDir, err)
	}

	mediaFilePath := filepath.Join(cacheDir, mediaFilename)

	fileExists, err := utilities.FileExists(mediaFilePath)
	if err != nil {
		return fmt.Errorf("unable to check if the media file is already downloaded: %w", err)
	}

	if !fileExists {
		if err := utilities.DownloadFile(mediaURL, mediaFilePath); err != nil {
			return fmt.Errorf("unable to download the media attachment: %w", err)
		}
	}

	// TODO: display the file in the image viewer.
	fmt.Println("checkpoint: the media file is now on disk; just need to open it in an image viewer...")

	return nil
}