package cmd

import (
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"time"

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

func draftAutoSaveCmd() *cobra.Command {
	cmd := &cobra.Command{
		Use:   "autosave",
		Short: "Configure draft auto-save",
		Long:  `Enable or configure automatic draft saving. Set interval, view status, and manage auto-save settings.`,
	}

	cmd.AddCommand(autosaveEnableCmd())
	cmd.AddCommand(autosaveDisableCmd())
	cmd.AddCommand(autosaveStatusCmd())
	cmd.AddCommand(autosaveConfigCmd())
	cmd.AddCommand(autosaveRunCmd())

	return cmd
}

func autosaveEnableCmd() *cobra.Command {
	var interval int

	cmd := &cobra.Command{
		Use:   "enable",
		Short: "Enable draft auto-save",
		Long:  `Enable automatic saving of draft messages at a configured interval.`,
		RunE: func(cmd *cobra.Command, args []string) error {
			if interval < 10 {
				interval = 30
			}
			if interval > 3600 {
				interval = 3600
			}

			cfgMgr := config.NewConfigManager()
			autoSaveConfig, err := loadAutoSaveConfig(cfgMgr)
			if err != nil {
				return fmt.Errorf("failed to load auto-save config: %w", err)
			}

			autoSaveConfig.Enabled = true
			autoSaveConfig.Interval = interval

			if err := saveAutoSaveConfig(cfgMgr, autoSaveConfig); err != nil {
				return fmt.Errorf("failed to save auto-save config: %w", err)
			}

			fmt.Printf("Draft auto-save enabled (interval: %d seconds)\n", interval)
			return nil
		},
	}

	cmd.Flags().IntVarP(&interval, "interval", "i", 30, "Auto-save interval in seconds (10-3600, default: 30)")

	return cmd
}

func autosaveDisableCmd() *cobra.Command {
	cmd := &cobra.Command{
		Use:   "disable",
		Short: "Disable draft auto-save",
		Long:  `Disable automatic saving of draft messages.`,
		RunE: func(cmd *cobra.Command, args []string) error {
			cfgMgr := config.NewConfigManager()
			autoSaveConfig, err := loadAutoSaveConfig(cfgMgr)
			if err != nil {
				return fmt.Errorf("failed to load auto-save config: %w", err)
			}

			autoSaveConfig.Enabled = false

			if err := saveAutoSaveConfig(cfgMgr, autoSaveConfig); err != nil {
				return fmt.Errorf("failed to save auto-save config: %w", err)
			}

			fmt.Println("Draft auto-save disabled")
			return nil
		},
	}

	return cmd
}

func autosaveStatusCmd() *cobra.Command {
	cmd := &cobra.Command{
		Use:   "status",
		Short: "Show auto-save status",
		Long:  `Display the current auto-save configuration and last save time.`,
		RunE: func(cmd *cobra.Command, args []string) error {
			cfgMgr := config.NewConfigManager()
			autoSaveConfig, err := loadAutoSaveConfig(cfgMgr)
			if err != nil {
				return fmt.Errorf("failed to load auto-save config: %w", err)
			}

			fmt.Printf("Enabled:  %t\n", autoSaveConfig.Enabled)
			fmt.Printf("Interval: %d seconds\n", autoSaveConfig.Interval)

			if autoSaveConfig.LastSaved > 0 {
				lastSaved := time.Unix(autoSaveConfig.LastSaved, 0)
				elapsed := time.Since(lastSaved)
				fmt.Printf("Last Save: %s (%s ago)\n", lastSaved.Format("2006-01-02 15:04:05"), elapsed.Round(time.Second).String())
			} else {
				fmt.Println("Last Save: Never")
			}

			return nil
		},
	}

	return cmd
}

func autosaveConfigCmd() *cobra.Command {
	var interval int

	cmd := &cobra.Command{
		Use:   "config",
		Short: "Configure auto-save settings",
		Long:  `Update auto-save interval and settings. Does not enable/disable auto-save.`,
		RunE: func(cmd *cobra.Command, args []string) error {
			if interval < 10 {
				interval = 30
			}
			if interval > 3600 {
				interval = 3600
			}

			cfgMgr := config.NewConfigManager()
			autoSaveConfig, err := loadAutoSaveConfig(cfgMgr)
			if err != nil {
				return fmt.Errorf("failed to load auto-save config: %w", err)
			}

			autoSaveConfig.Interval = interval

			if err := saveAutoSaveConfig(cfgMgr, autoSaveConfig); err != nil {
				return fmt.Errorf("failed to save auto-save config: %w", err)
			}

			fmt.Printf("Auto-save interval updated to %d seconds\n", interval)
			return nil
		},
	}

	cmd.Flags().IntVarP(&interval, "interval", "i", 0, "New auto-save interval in seconds (10-3600)")
	_ = cmd.MarkFlagRequired("interval")

	return cmd
}

func autosaveRunCmd() *cobra.Command {
	var draftID string

	cmd := &cobra.Command{
		Use:   "run",
		Short: "Manually trigger auto-save",
		Long:  `Manually trigger the auto-save process for the current draft or a specific draft.`,
		RunE: func(cmd *cobra.Command, args []string) error {
			cfgMgr := config.NewConfigManager()
			autoSaveConfig, err := loadAutoSaveConfig(cfgMgr)
			if err != nil {
				return fmt.Errorf("failed to load auto-save config: %w", err)
			}

			if !autoSaveConfig.Enabled {
				fmt.Println("Auto-save is disabled. Enable with 'pop draft autosave enable'")
				return nil
			}

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

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

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

			localDrafts, err := loadLocalDrafts(cfgMgr)
			if err != nil {
				return fmt.Errorf("failed to load local drafts: %w", err)
			}

			if draftID == "" {
				draftID = getLastEditedDraft(localDrafts)
				if draftID == "" {
					fmt.Println("No active draft to save")
					return nil
				}
			}

			localDraft, found := findLocalDraft(localDrafts, draftID)
			if !found {
				return fmt.Errorf("draft not found: %s", draftID)
			}

			draft := internalmail.Draft{
				MessageID: localDraft.MessageID,
				To:        localDraft.To,
				CC:        localDraft.CC,
				BCC:       localDraft.BCC,
				Subject:   localDraft.Subject,
				Body:      localDraft.Body,
			}

			var errResult error
			if localDraft.MessageID == "" {
				id, err := mailClient.SaveDraft(draft, session.MailPassphrase)
				if err != nil {
					errResult = fmt.Errorf("failed to save draft: %w", err)
				} else {
					localDraft.MessageID = id
					fmt.Printf("Draft saved with ID: %s\n", id)
				}
			} else {
				errResult = mailClient.UpdateDraft(localDraft.MessageID, draft, session.MailPassphrase)
				if errResult != nil {
					errResult = fmt.Errorf("failed to update draft: %w", errResult)
				} else {
					fmt.Printf("Draft updated: %s\n", localDraft.MessageID)
				}
			}

			if errResult == nil {
				localDraft.LastEdited = time.Now().Unix()
				autoSaveConfig.LastSaved = time.Now().Unix()
				saveLocalDrafts(cfgMgr, localDrafts)
				saveAutoSaveConfig(cfgMgr, autoSaveConfig)
			}

			return errResult
		},
	}

	cmd.Flags().StringVarP(&draftID, "draft", "d", "", "Specific draft ID to save (default: most recently edited)")

	return cmd
}

func draftTemplateCmd() *cobra.Command {
	cmd := &cobra.Command{
		Use:   "template",
		Short: "Manage email templates",
		Long:  `Save and reuse email templates for quick draft creation.`,
	}

	cmd.AddCommand(templateSaveCmd())
	cmd.AddCommand(templateListCmd())
	cmd.AddCommand(templateUseCmd())
	cmd.AddCommand(templateDeleteCmd())

	return cmd
}

func templateSaveCmd() *cobra.Command {
	var name, subject, body, bodyFile string

	cmd := &cobra.Command{
		Use:   "save <name>",
		Short: "Save an email template",
		Long:  `Save a subject and body as a reusable email template.`,
		Args:  cobra.MaximumNArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			templateName := name
			if len(args) > 0 && args[0] != "" {
				templateName = args[0]
			}
			if templateName == "" {
				return fmt.Errorf("template name is required")
			}

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

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

			templates[templateName] = DraftTemplate{
				Name:    templateName,
				Subject: subject,
				Body:    msgBody,
				SavedAt: time.Now().Format(time.RFC3339),
			}

			if err := saveTemplates(cfgMgr, templates); err != nil {
				return fmt.Errorf("failed to save templates: %w", err)
			}

			fmt.Printf("Template '%s' saved\n", templateName)
			return nil
		},
	}

	cmd.Flags().StringVar(&name, "name", "", "Template name (or pass as positional argument)")
	cmd.Flags().StringVarP(&subject, "subject", "s", "", "Template subject")
	cmd.Flags().StringVarP(&bodyFile, "body-file", "f", "", "File containing template body")
	cmd.Flags().StringVar(&body, "body", "", "Inline template body")

	return cmd
}

func templateListCmd() *cobra.Command {
	cmd := &cobra.Command{
		Use:   "list",
		Short: "List email templates",
		Long:  `List all saved email templates.`,
		RunE: func(cmd *cobra.Command, args []string) error {
			cfgMgr := config.NewConfigManager()
			templates, err := loadTemplates(cfgMgr)
			if err != nil {
				return fmt.Errorf("failed to load templates: %w", err)
			}

			if len(templates) == 0 {
				fmt.Println("No templates saved")
				return nil
			}

			for _, t := range templates {
				subject := t.Subject
				if len(subject) > 50 {
					subject = subject[:47] + "..."
				}
				fmt.Printf("  %-20s %-50s %s\n", t.Name, subject, t.SavedAt)
			}

			return nil
		},
	}

	return cmd
}

func templateUseCmd() *cobra.Command {
	var to string

	cmd := &cobra.Command{
		Use:   "use <name>",
		Short: "Use an email template",
		Long:  `Load an email template and create a draft from it.`,
		Args:  cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			templateName := args[0]

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

			template, found := templates[templateName]
			if !found {
				return fmt.Errorf("template not found: %s", templateName)
			}

			var recipients []internalmail.Recipient
			if to != "" {
				recipients = parseRecipients(to)
			}

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

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

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

			draft := internalmail.Draft{
				To:      recipients,
				Subject: template.Subject,
				Body:    template.Body,
			}

			id, err := mailClient.SaveDraft(draft, session.MailPassphrase)
			if err != nil {
				return fmt.Errorf("failed to create draft from template: %w", err)
			}

			fmt.Printf("Draft created from template '%s' with ID: %s\n", templateName, id)
			return nil
		},
	}

	cmd.Flags().StringVarP(&to, "to", "t", "", "Recipient addresses (comma-separated)")

	return cmd
}

func templateDeleteCmd() *cobra.Command {
	cmd := &cobra.Command{
		Use:   "delete <name>",
		Short: "Delete an email template",
		Long:  `Delete a saved email template.`,
		Args:  cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			templateName := args[0]

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

			if _, found := templates[templateName]; !found {
				return fmt.Errorf("template not found: %s", templateName)
			}

			delete(templates, templateName)

			if err := saveTemplates(cfgMgr, templates); err != nil {
				return fmt.Errorf("failed to save templates: %w", err)
			}

			fmt.Printf("Template '%s' deleted\n", templateName)
			return nil
		},
	}

	return cmd
}

type DraftTemplate struct {
	Name    string `json:"name"`
	Subject string `json:"subject"`
	Body    string `json:"body"`
	SavedAt string `json:"saved_at"`
}

type LocalDraft struct {
	MessageID  string             `json:"message_id"`
	To         []internalmail.Recipient `json:"to"`
	CC         []internalmail.Recipient `json:"cc,omitempty"`
	BCC        []internalmail.Recipient `json:"bcc,omitempty"`
	Subject    string             `json:"subject"`
	Body       string             `json:"body"`
	LastEdited int64              `json:"last_edited"`
}

func getAutoSaveConfigPath(cfgMgr *config.ConfigManager) string {
	return filepath.Join(cfgMgr.ConfigDir(), "autosave.json")
}

func loadAutoSaveConfig(cfgMgr *config.ConfigManager) (*internalmail.DraftAutoSaveConfig, error) {
	path := getAutoSaveConfigPath(cfgMgr)
	data, err := os.ReadFile(path)
	if err != nil {
		if os.IsNotExist(err) {
			return &internalmail.DraftAutoSaveConfig{
				Enabled:  false,
				Interval: 30,
			}, nil
		}
		return nil, err
	}

	var config internalmail.DraftAutoSaveConfig
	if err := json.Unmarshal(data, &config); err != nil {
		return nil, err
	}

	return &config, nil
}

func saveAutoSaveConfig(cfgMgr *config.ConfigManager, autoSaveConfig *internalmail.DraftAutoSaveConfig) error {
	path := getAutoSaveConfigPath(cfgMgr)
	data, err := json.MarshalIndent(autoSaveConfig, "", "  ")
	if err != nil {
		return err
	}

	if err := os.MkdirAll(cfgMgr.ConfigDir(), 0700); err != nil {
		return err
	}

	return os.WriteFile(path, data, 0600)
}

func getLocalDraftsPath(cfgMgr *config.ConfigManager) string {
	return filepath.Join(cfgMgr.ConfigDir(), "local-drafts.json")
}

func loadLocalDrafts(cfgMgr *config.ConfigManager) ([]LocalDraft, error) {
	path := getLocalDraftsPath(cfgMgr)
	data, err := os.ReadFile(path)
	if err != nil {
		if os.IsNotExist(err) {
			return []LocalDraft{}, nil
		}
		return nil, err
	}

	var drafts []LocalDraft
	if err := json.Unmarshal(data, &drafts); err != nil {
		return nil, err
	}

	return drafts, nil
}

func saveLocalDrafts(cfgMgr *config.ConfigManager, drafts []LocalDraft) error {
	path := getLocalDraftsPath(cfgMgr)
	data, err := json.MarshalIndent(drafts, "", "  ")
	if err != nil {
		return err
	}

	if err := os.MkdirAll(cfgMgr.ConfigDir(), 0700); err != nil {
		return err
	}

	return os.WriteFile(path, data, 0600)
}

func getLastEditedDraft(drafts []LocalDraft) string {
	var lastID string
	var lastTime int64
	for _, d := range drafts {
		if d.LastEdited > lastTime {
			lastTime = d.LastEdited
			lastID = d.MessageID
			if lastID == "" {
				lastID = fmt.Sprintf("local-%d", d.LastEdited)
			}
		}
	}
	return lastID
}

func findLocalDraft(drafts []LocalDraft, id string) (LocalDraft, bool) {
	for _, d := range drafts {
		if d.MessageID == id {
			return d, true
		}
	}
	return LocalDraft{}, false
}

func getTemplatesPath(cfgMgr *config.ConfigManager) string {
	return filepath.Join(cfgMgr.ConfigDir(), "templates.json")
}

func loadTemplates(cfgMgr *config.ConfigManager) (map[string]DraftTemplate, error) {
	path := getTemplatesPath(cfgMgr)
	data, err := os.ReadFile(path)
	if err != nil {
		if os.IsNotExist(err) {
			return map[string]DraftTemplate{}, nil
		}
		return nil, err
	}

	var templates map[string]DraftTemplate
	if err := json.Unmarshal(data, &templates); err != nil {
		return nil, err
	}

	return templates, nil
}

func saveTemplates(cfgMgr *config.ConfigManager, templates map[string]DraftTemplate) error {
	path := getTemplatesPath(cfgMgr)
	data, err := json.MarshalIndent(templates, "", "  ")
	if err != nil {
		return err
	}

	if err := os.MkdirAll(cfgMgr.ConfigDir(), 0700); err != nil {
		return err
	}

	return os.WriteFile(path, data, 0600)
}