package cmd

import (
	"fmt"
	"os"
	"strconv"
	"strings"
	"text/tabwriter"

	"github.com/frenocorp/pop/internal/api"
	"github.com/frenocorp/pop/internal/config"
	internalmail "github.com/frenocorp/pop/internal/mail"
	"github.com/spf13/cobra"
)

func threadCmd() *cobra.Command {
	cmd := &cobra.Command{
		Use:   "thread",
		Short: "Manage email conversations",
		Long:  `View, reply to, and manage email conversation threads.`,
	}

	cmd.AddCommand(threadListCmd())
	cmd.AddCommand(threadShowCmd())
	cmd.AddCommand(threadReplyCmd())

	return cmd
}

func threadListCmd() *cobra.Command {
	var page, pageSize string

	cmd := &cobra.Command{
		Use:   "list",
		Short: "List conversation threads",
		Long:  `List email conversation threads sorted by latest activity.`,
		RunE: func(cmd *cobra.Command, args []string) error {
			pageVal, err := strconv.Atoi(page)
			if err != nil || pageVal < 1 {
				pageVal = 1
			}

			pageSizeVal, err := strconv.Atoi(pageSize)
			if err != nil || pageSizeVal < 1 {
				pageSizeVal = 20
			}
			if pageSizeVal > 100 {
				pageSizeVal = 100
			}

			cfgMgr := config.NewConfigManager()
			cfg, err := cfgMgr.Load()
			if err != nil {
				return fmt.Errorf("failed to load config: %w", err)
			}

			session, sessionMgr, err := checkAuthenticatedWithManager()
			if err != nil {
				return err
			}

			client := api.NewProtonMailClient(cfg, sessionMgr)
			client.SetAuthHeader(session.AccessToken)
			mailClient := internalmail.NewClient(client)

			result, err := mailClient.ListConversations(pageVal, pageSizeVal, session.MailPassphrase)
			if err != nil {
				return fmt.Errorf("failed to list conversations: %w", err)
			}

			if len(result.Conversations) == 0 {
				fmt.Println("No conversations found")
				return nil
			}

			return printConversations(result.Conversations)
		},
	}

	cmd.Flags().StringVar(&page, "page", "1", "Page number")
	cmd.Flags().StringVar(&pageSize, "page-size", "20", "Conversations per page (max 100)")

	return cmd
}

func threadShowCmd() *cobra.Command {
	cmd := &cobra.Command{
		Use:   "show <conversation-id>",
		Short: "Show a conversation thread",
		Long:  `Display all messages in a conversation thread in chronological order.`,
		Args:  cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			convID := args[0]

			cfgMgr := config.NewConfigManager()
			cfg, err := cfgMgr.Load()
			if err != nil {
				return fmt.Errorf("failed to load config: %w", err)
			}

			session, sessionMgr, err := checkAuthenticatedWithManager()
			if err != nil {
				return err
			}

			client := api.NewProtonMailClient(cfg, sessionMgr)
			client.SetAuthHeader(session.AccessToken)
			mailClient := internalmail.NewClient(client)

			req := internalmail.GetConversationRequest{
				ConversationID: convID,
				Passphrase:     session.MailPassphrase,
			}

			result, err := mailClient.GetConversation(req)
			if err != nil {
				return fmt.Errorf("failed to get conversation: %w", err)
			}

			fmt.Printf("Conversation: %s\n", result.Subject)
			fmt.Printf("Messages: %d\n", result.MessageCount)
			fmt.Printf("Participants: %s\n", formatRecipients(result.Participants))
			fmt.Println()

			for i, msg := range result.Messages {
				from := msg.Sender.DisplayName()
				date := msg.CreatedAt.Format("2006-01-02 15:04")
				subject := msg.Subject
				if len(subject) > 60 {
					subject = subject[:57] + "..."
				}

				fmt.Printf("--- Message %d ---\n", i+1)
				fmt.Printf("From:  %s\n", from)
				fmt.Printf("Date:  %s\n", date)
				fmt.Printf("Subject: %s\n", subject)

				if msg.Body != "" {
					body := msg.Body
					if len(body) > 200 {
						body = body[:197] + "..."
					}
					fmt.Printf("Body:  %s\n", body)
				}
				fmt.Println()
			}

			return nil
		},
	}

	return cmd
}

func threadReplyCmd() *cobra.Command {
	var body, bodyFile, subject string
	var html bool

	cmd := &cobra.Command{
		Use:   "reply <conversation-id>",
		Short: "Reply to a conversation",
		Long:  `Reply to the latest message in a conversation thread.`,
		Args:  cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			convID := args[0]

			cfgMgr := config.NewConfigManager()
			cfg, err := cfgMgr.Load()
			if err != nil {
				return fmt.Errorf("failed to load config: %w", err)
			}

			session, sessionMgr, err := checkAuthenticatedWithManager()
			if err != nil {
				return err
			}

			client := api.NewProtonMailClient(cfg, sessionMgr)
			client.SetAuthHeader(session.AccessToken)
			mailClient := internalmail.NewClient(client)

			req := internalmail.GetConversationRequest{
				ConversationID: convID,
				Passphrase:     session.MailPassphrase,
			}

			conv, err := mailClient.GetConversation(req)
			if err != nil {
				return fmt.Errorf("failed to get conversation: %w", err)
			}

			if len(conv.Messages) == 0 {
				return fmt.Errorf("conversation has no messages")
			}

			latestMsg := conv.Messages[len(conv.Messages)-1]

			var bodyContent string
			if body != "" {
				bodyContent = body
			} else if bodyFile != "" {
				data, err := os.ReadFile(bodyFile)
				if err != nil {
					return fmt.Errorf("failed to read body file: %w", err)
				}
				bodyContent = string(data)
			}

			replySubject := subject
			if replySubject == "" {
				replySubject = "Re: " + latestMsg.Subject
			}

			replyTo := []internalmail.Recipient{latestMsg.Sender.ToRecipient()}

			sendReq := internalmail.SendRequest{
				To:         replyTo,
				Subject:    replySubject,
				Body:       bodyContent,
				HTML:       html,
				InReplyTo:  latestMsg.MimeMessageID,
				References: latestMsg.ConversationID,
				Passphrase: session.MailPassphrase,
			}

			if err := mailClient.Send(sendReq); err != nil {
				return fmt.Errorf("failed to send reply: %w", err)
			}

			fmt.Println("Reply sent successfully")
			return nil
		},
	}

	cmd.Flags().StringVarP(&subject, "subject", "s", "", "Reply subject (default: Re: <original>)")
	cmd.Flags().StringVarP(&bodyFile, "body-file", "f", "", "File containing reply body")
	cmd.Flags().BoolVar(&html, "html", false, "Send body as HTML")
	cmd.Flags().StringVar(&body, "body", "", "Inline reply body")

	return cmd
}

func printConversations(conversations []internalmail.Conversation) error {
	w := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0)
	fmt.Fprintln(w, "ID\tSubject\tMessages\tLast From\tLast Date")
	fmt.Fprintln(w, "--\t-------\t--------\t---------\t---------")

	for _, conv := range conversations {
		id := conv.ConversationID
		if len(id) > 12 {
			id = id[:12]
		}

		subject := conv.Subject
		if len(subject) > 50 {
			subject = subject[:47] + "..."
		}

		lastFrom := "-"
		lastDate := "-"
		if conv.LastMessage != nil {
			lastFrom = conv.LastMessage.Sender.DisplayName()
			lastDate = conv.LastMessage.CreatedAt.Format("2006-01-02 15:04")
		}

		fmt.Fprintf(w, "%s\t%s\t%d\t%s\t%s\n", id, subject, conv.MessageCount, lastFrom, lastDate)
	}

	return w.Flush()
}

func formatThreadParticipants(participants []internalmail.Recipient) string {
	parts := make([]string, len(participants))
	for i, p := range participants {
		parts[i] = p.DisplayName()
	}
	return strings.Join(parts, ", ")
}