package telegram

// TelegramRepository provides GORM-based persistence for Telegram channel data.
// Reference: Chatwoot uses ActiveRecord for ChannelTelegram CRUD with callbacks:
//   - before_validation :ensure_valid_bot_token
//   - before_save :setup_telegram_webhook
//   - after_destroy :delete_telegram_webhook
//
// Design: Repository pattern abstracts GORM operations, matching gochat's
// existing repository pattern used by other channel providers.

import (
	"context"
	"fmt"
	"time"

	channelmodel "github.com/gochat/gochat/internal/model/channel"
	"github.com/gochat/gochat/internal/model"

	"gorm.io/gorm"
	applogger "github.com/gochat/gochat/pkg/logger"
)

// Repository handles Telegram channel database operations.
type Repository struct {
	db *gorm.DB
}

// NewRepository creates a Telegram repository with GORM DB.
func NewRepository(db *gorm.DB) *Repository {
	return &Repository{db: db}
}

// === CRUD Operations ===

// Create persists a new ChannelTelegram record.
// Reference: Chatwoot ChannelTelegram.create with before_validation + before_save callbacks
//
// The Chatwoot model has these lifecycle hooks:
//   before_validation :ensure_valid_bot_token → validates via getMe API
//   before_save :setup_telegram_webhook → calls setWebhook API
//   after_destroy :delete_telegram_webhook → calls deleteWebhook API
//
// In gochat, we implement these as explicit service-level operations rather than
// model callbacks, since Go doesn't have ActiveRecord-style lifecycle hooks.
func (r *Repository) Create(ctx context.Context, channel *channelmodel.ChannelTelegram) error {
	if err := r.db.WithContext(ctx).Create(channel).Error; err != nil {
		return fmt.Errorf("failed to create ChannelTelegram: %w", err)
	}

	applogger.L().Info("ChannelTelegram created",
		"id", channel.ID,
		"account_id", channel.AccountID,
		"bot_name", channel.BotName,
	)
	return nil
}

// Update modifies a ChannelTelegram record.
// Reference: Chatwoot ChannelTelegram.update — only bot_token is editable
func (r *Repository) Update(ctx context.Context, channel *channelmodel.ChannelTelegram) error {
	result := r.db.WithContext(ctx).Save(channel)
	if result.Error != nil {
		return fmt.Errorf("failed to update ChannelTelegram: %w", result.Error)
	}

	if result.RowsAffected == 0 {
		return fmt.Errorf("ChannelTelegram not found (id=%d)", channel.ID)
	}

	applogger.L().Info("ChannelTelegram updated", "id", channel.ID)
	return nil
}

// UpdateBotToken updates only the bot_token field (and re-validates + re-sets webhook).
// Reference: Chatwoot only allows bot_token updates on existing channels
func (r *Repository) UpdateBotToken(ctx context.Context, channelID uint, newBotToken string) error {
	result := r.db.WithContext(ctx).
		Model(&channelmodel.ChannelTelegram{}).
		Where("id = ?", channelID).
		Update("bot_token", newBotToken)

	if result.Error != nil {
		return fmt.Errorf("failed to update bot_token: %w", result.Error)
	}

	if result.RowsAffected == 0 {
		return fmt.Errorf("ChannelTelegram not found (id=%d)", channelID)
	}

	applogger.L().Info("ChannelTelegram bot_token updated", "id", channelID)
	return nil
}

// UpdateWelcomeMessage updates only the welcome_message field.
func (r *Repository) UpdateWelcomeMessage(ctx context.Context, channelID uint, welcomeMessage string) error {
	result := r.db.WithContext(ctx).
		Model(&channelmodel.ChannelTelegram{}).
		Where("id = ?", channelID).
		Update("welcome_message", welcomeMessage)

	if result.Error != nil {
		return fmt.Errorf("failed to update welcome_message: %w", result.Error)
	}

	return nil
}

// Delete removes a ChannelTelegram record (soft delete via GORM).
// Reference: Chatwoot after_destroy :delete_telegram_webhook
// Note: The webhook cleanup should be done BEFORE calling this Delete method
// (in the service layer), since Go doesn't have after_destroy callbacks.
func (r *Repository) Delete(ctx context.Context, channelID uint) error {
	result := r.db.WithContext(ctx).
		Where("id = ?", channelID).
		Delete(&channelmodel.ChannelTelegram{})

	if result.Error != nil {
		return fmt.Errorf("failed to delete ChannelTelegram: %w", result.Error)
	}

	if result.RowsAffected == 0 {
		return fmt.Errorf("ChannelTelegram not found (id=%d)", channelID)
	}

	applogger.L().Info("ChannelTelegram deleted", "id", channelID)
	return nil
}

// === Query Operations ===

// FindByID retrieves a ChannelTelegram by its primary key.
func (r *Repository) FindByID(ctx context.Context, channelID uint) (*channelmodel.ChannelTelegram, error) {
	var channel channelmodel.ChannelTelegram
	if err := r.db.WithContext(ctx).First(&channel, channelID).Error; err != nil {
		if err == gorm.ErrRecordNotFound {
			return nil, fmt.Errorf("ChannelTelegram not found (id=%d)", channelID)
		}
		return nil, fmt.Errorf("failed to find ChannelTelegram: %w", err)
	}
	return &channel, nil
}

// FindByBotToken retrieves a ChannelTelegram by its bot_token.
// Reference: Chatwoot finds inbox by bot_token for webhook routing
func (r *Repository) FindByBotToken(ctx context.Context, botToken string) (*channelmodel.ChannelTelegram, error) {
	var channel channelmodel.ChannelTelegram
	if err := r.db.WithContext(ctx).Where("bot_token = ?", botToken).First(&channel).Error; err != nil {
		if err == gorm.ErrRecordNotFound {
			return nil, fmt.Errorf("ChannelTelegram not found for bot_token")
		}
		return nil, fmt.Errorf("failed to find ChannelTelegram by bot_token: %w", err)
	}
	return &channel, nil
}

// FindByAccountID retrieves all ChannelTelegram records for an account.
// Reference: Chatwoot scopes channels to account (account_id foreign key)
func (r *Repository) FindByAccountID(ctx context.Context, accountID uint) ([]channelmodel.ChannelTelegram, error) {
	var channels []channelmodel.ChannelTelegram
	if err := r.db.WithContext(ctx).
		Where("account_id = ?", accountID).
		Find(&channels).Error; err != nil {
		return nil, fmt.Errorf("failed to find ChannelTelegram by account_id: %w", err)
	}
	return channels, nil
}

// FindByInboxID retrieves the ChannelTelegram associated with an Inbox.
// Reference: Chatwoot: inbox.channel (polymorphic association)
func (r *Repository) FindByInboxID(ctx context.Context, inboxID uint) (*channelmodel.ChannelTelegram, error) {
	var channel channelmodel.ChannelTelegram
	if err := r.db.WithContext(ctx).Where("inbox_id = ?", inboxID).First(&channel).Error; err != nil {
		if err == gorm.ErrRecordNotFound {
			return nil, fmt.Errorf("ChannelTelegram not found for inbox_id=%d", inboxID)
		}
		return nil, fmt.Errorf("failed to find ChannelTelegram by inbox_id: %w", err)
	}
	return &channel, nil
}

// === Inbox Repository ===

// InboxRepository handles Inbox model operations for Telegram channels.
// Reference: Chatwoot creates Inbox alongside ChannelTelegram
type InboxRepository struct {
	db *gorm.DB
}

// NewInboxRepository creates an Inbox repository.
func NewInboxRepository(db *gorm.DB) *InboxRepository {
	return &InboxRepository{db: db}
}

// FindByBotToken finds the Inbox associated with a Telegram bot token.
// This is the primary lookup for webhook routing.
// Reference: Chatwoot: Inbox.joins(:channel_telegram).find_by(channel_telegrams: {bot_token: token})
func (r *InboxRepository) FindByBotToken(ctx context.Context, botToken string) (*model.Inbox, error) {
	var channel channelmodel.ChannelTelegram
	if err := r.db.WithContext(ctx).Where("bot_token = ?", botToken).First(&channel).Error; err != nil {
		return nil, fmt.Errorf("no ChannelTelegram found for bot_token: %w", err)
	}

	var inbox model.Inbox
	if err := r.db.WithContext(ctx).
		Where("channel_type = ? AND id = ?", "telegram", channel.InboxID).
		First(&inbox).Error; err != nil {
		return nil, fmt.Errorf("no Inbox found for ChannelTelegram: %w", err)
	}

	return &inbox, nil
}

// CreateWithChannel creates an Inbox and its associated ChannelTelegram in one transaction.
// Reference: Chatwoot creates both Inbox and ChannelTelegram together
func (r *InboxRepository) CreateWithChannel(ctx context.Context, accountID uint, name string, channelTelegram *channelmodel.ChannelTelegram) (*model.Inbox, error) {
	inbox := &model.Inbox{
		AccountID:   accountID,
		Name:        name,
		ChannelType: "telegram",
	}

	err := r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		// Create Inbox first
		if err := tx.Create(inbox).Error; err != nil {
			return fmt.Errorf("failed to create Inbox: %w", err)
		}

		// Set InboxID on ChannelTelegram and create
		channelTelegram.InboxID = inbox.ID
		if err := tx.Create(channelTelegram).Error; err != nil {
			return fmt.Errorf("failed to create ChannelTelegram: %w", err)
		}

		return nil
	})

	if err != nil {
		return nil, err
	}

	applogger.L().Info("Telegram Inbox created with Channel",
		"inbox_id", inbox.ID,
		"account_id", accountID,
	)
	return inbox, nil
}

// === Auto-Migration ===

// AutoMigrate runs GORM auto-migration for ChannelTelegram model.
func (r *Repository) AutoMigrate(ctx context.Context) error {
	if err := r.db.WithContext(ctx).AutoMigrate(&channelmodel.ChannelTelegram{}); err != nil {
		return fmt.Errorf("failed to auto-migrate ChannelTelegram: %w", err)
	}
	applogger.L().Info("ChannelTelegram auto-migration completed")
	return nil
}

// === Reauthorization Tracking ===

// MarkReauthorizationRequired flags a channel as needing bot token reauthorization.
// Reference: Chatwoot tracks reauthorization_required on ChannelTelegram
// when webhook delivery fails or bot token becomes invalid.
func (r *Repository) MarkReauthorizationRequired(ctx context.Context, channelID uint, reason string) error {
	result := r.db.WithContext(ctx).
		Model(&channelmodel.ChannelTelegram{}).
		Where("id = ?", channelID).
		Updates(map[string]interface{}{
			"reauthorization_required": true,
			"updated_at":               time.Now(),
		})

	if result.Error != nil {
		return fmt.Errorf("failed to mark reauthorization_required: %w", result.Error)
	}

	applogger.L().Warn("ChannelTelegram marked for reauthorization",
		"id", channelID,
		"reason", reason,
	)
	return nil
}

// ClearReauthorizationRequired clears the reauthorization flag after successful reauth.
func (r *Repository) ClearReauthorizationRequired(ctx context.Context, channelID uint) error {
	result := r.db.WithContext(ctx).
		Model(&channelmodel.ChannelTelegram{}).
		Where("id = ?", channelID).
		Updates(map[string]interface{}{
			"reauthorization_required": false,
			"updated_at":               time.Now(),
		})

	if result.Error != nil {
		return fmt.Errorf("failed to clear reauthorization_required: %w", result.Error)
	}

	return nil
}