package fedwiki

import (
	"context"
	"database/sql"
	"fmt"
	"log/slog"
	"time"

	"git.coopcloud.tech/wiki-cafe/member-console/internal/db"
	"go.temporal.io/sdk/temporal"
	"go.temporal.io/sdk/workflow"
)

// SyncFedWikiSitesWorkflowInput is the input for the SyncFedWikiSitesWorkflow.
type SyncFedWikiSitesWorkflowInput struct {
	// DefaultUserID is the user ID to assign to sites that don't have a known owner.
	// This is typically a system/admin user ID.
	DefaultUserID int64
}

// SyncFedWikiSitesWorkflowOutput is the output for the SyncFedWikiSitesWorkflow.
type SyncFedWikiSitesWorkflowOutput struct {
	Success       bool
	SitesFound    int
	SitesAdded    int
	SitesRemoved  int
	ErrorMessage  string
	SyncTimestamp time.Time
}

// SyncActivityOptions returns activity options for sync operations.
func SyncActivityOptions() workflow.ActivityOptions {
	return workflow.ActivityOptions{
		StartToCloseTimeout: 5 * time.Minute,
		RetryPolicy: &temporal.RetryPolicy{
			InitialInterval:    time.Second,
			BackoffCoefficient: 2.0,
			MaximumInterval:    time.Minute,
			MaximumAttempts:    5,
		},
	}
}

// SyncFedWikiSitesWorkflow synchronizes sites from the FedWiki farm to the local database.
// It fetches all sites from the FarmManager API and ensures the local database reflects
// the current state of the farm.
func SyncFedWikiSitesWorkflow(ctx workflow.Context, input SyncFedWikiSitesWorkflowInput) (*SyncFedWikiSitesWorkflowOutput, error) {
	logger := workflow.GetLogger(ctx)
	logger.Info("SyncFedWikiSitesWorkflow started",
		"defaultUserID", input.DefaultUserID)

	var activities *Activities
	activityCtx := workflow.WithActivityOptions(ctx, SyncActivityOptions())

	// Step 1: Fetch all sites from the FedWiki farm
	var listResult *ListFedWikiSitesOutput
	err := workflow.ExecuteActivity(activityCtx, activities.ListFedWikiSitesActivity, ListFedWikiSitesInput{}).Get(ctx, &listResult)
	if err != nil {
		logger.Error("Failed to list sites from FedWiki farm", "error", err)
		return &SyncFedWikiSitesWorkflowOutput{
			Success:       false,
			ErrorMessage:  "Failed to fetch sites from FedWiki farm. Please try again later.",
			SyncTimestamp: workflow.Now(ctx),
		}, nil
	}

	logger.Info("Fetched sites from FedWiki farm", "count", len(listResult.Sites))

	// Step 2: Sync the sites to the local database
	var syncResult *SyncSitesToDBOutput
	err = workflow.ExecuteActivity(activityCtx, activities.SyncSitesToDBActivity, SyncSitesToDBInput{
		FarmSites:     listResult.Sites,
		DefaultUserID: input.DefaultUserID,
	}).Get(ctx, &syncResult)
	if err != nil {
		logger.Error("Failed to sync sites to database", "error", err)
		return &SyncFedWikiSitesWorkflowOutput{
			Success:       false,
			SitesFound:    len(listResult.Sites),
			ErrorMessage:  "Failed to sync sites to local database.",
			SyncTimestamp: workflow.Now(ctx),
		}, nil
	}

	logger.Info("SyncFedWikiSitesWorkflow completed successfully",
		"sitesFound", len(listResult.Sites),
		"sitesAdded", syncResult.SitesAdded,
		"sitesRemoved", syncResult.SitesRemoved)

	return &SyncFedWikiSitesWorkflowOutput{
		Success:       true,
		SitesFound:    len(listResult.Sites),
		SitesAdded:    syncResult.SitesAdded,
		SitesRemoved:  syncResult.SitesRemoved,
		SyncTimestamp: workflow.Now(ctx),
	}, nil
}

// SyncSitesToDBInput is the input for the SyncSitesToDB activity.
type SyncSitesToDBInput struct {
	FarmSites     []SiteInfo
	DefaultUserID int64
}

// SyncSitesToDBOutput is the output for the SyncSitesToDB activity.
type SyncSitesToDBOutput struct {
	SitesAdded   int
	SitesUpdated int
	SitesRemoved int
}

// SyncSitesToDBActivity synchronizes sites from the FedWiki farm to the local database.
// It adds new sites, updates ownership for existing sites, and removes sites that no longer exist on the farm.
func (a *Activities) SyncSitesToDBActivity(ctx context.Context, input SyncSitesToDBInput) (*SyncSitesToDBOutput, error) {
	a.Logger.Info("syncing sites to database",
		slog.Int("farmSiteCount", len(input.FarmSites)),
		slog.Int64("defaultUserID", input.DefaultUserID))

	// Get all current sites from the local database (we need full site info for ownership comparison)
	localSites, err := a.DB.GetAllSites(ctx)
	if err != nil {
		a.Logger.Error("failed to get local sites", slog.Any("error", err))
		return nil, fmt.Errorf("failed to get local sites: %w", err)
	}

	// Create a map of local sites by domain for quick lookup
	localSiteMap := make(map[string]db.Site, len(localSites))
	for _, site := range localSites {
		localSiteMap[site.Domain] = site
	}

	// Create a map of farm domains for quick lookup
	farmDomainMap := make(map[string]SiteInfo, len(input.FarmSites))
	for _, site := range input.FarmSites {
		farmDomainMap[site.Name] = site
	}

	sitesAdded := 0
	sitesUpdated := 0
	sitesRemoved := 0

	// Add or update sites from the farm
	for _, farmSite := range input.FarmSites {
		// Skip inactive sites
		if farmSite.Status != "active" {
			a.Logger.Debug("skipping inactive site", slog.String("domain", farmSite.Name), slog.String("status", farmSite.Status))
			continue
		}

		// Resolve the owner's OIDC subject to a user ID
		ownerOIDCSubject := farmSite.Owner.OAuth2.ID
		userID := input.DefaultUserID

		if ownerOIDCSubject != "" {
			// Try to find the user by their OIDC subject
			user, err := a.DB.GetUserByOIDCSubject(ctx, ownerOIDCSubject)
			if err == nil {
				userID = user.ID
				a.Logger.Debug("resolved site owner to user",
					slog.String("domain", farmSite.Name),
					slog.String("ownerOIDC", ownerOIDCSubject),
					slog.Int64("userID", userID))
			} else {
				a.Logger.Debug("site owner not found in DB, using default user",
					slog.String("domain", farmSite.Name),
					slog.String("ownerOIDC", ownerOIDCSubject),
					slog.Int64("defaultUserID", input.DefaultUserID))
			}
		}

		localSite, exists := localSiteMap[farmSite.Name]
		if !exists {
			// Site exists on farm but not locally - add it
			_, err := a.DB.UpsertSiteByDomain(ctx, db.UpsertSiteByDomainParams{
				UserID:           userID,
				Domain:           farmSite.Name,
				IsCustomDomain:   0, // Assume standard domain for synced sites
				OwnerOidcSubject: toNullString(ownerOIDCSubject),
			})
			if err != nil {
				a.Logger.Error("failed to add site",
					slog.String("domain", farmSite.Name),
					slog.Any("error", err))
				continue
			}
			sitesAdded++
			a.Logger.Info("added site from farm",
				slog.String("domain", farmSite.Name),
				slog.Int64("userID", userID),
				slog.String("ownerOIDC", ownerOIDCSubject))
		} else {
			// Site exists locally - check if ownership needs updating
			currentOwnerOIDC := fromNullString(localSite.OwnerOidcSubject)
			if currentOwnerOIDC != ownerOIDCSubject || localSite.UserID != userID {
				// Ownership has changed - update it
				err := a.DB.UpdateSiteOwnership(ctx, db.UpdateSiteOwnershipParams{
					UserID:           userID,
					OwnerOidcSubject: toNullString(ownerOIDCSubject),
					Domain:           farmSite.Name,
				})
				if err != nil {
					a.Logger.Error("failed to update site ownership",
						slog.String("domain", farmSite.Name),
						slog.Any("error", err))
					continue
				}
				sitesUpdated++
				a.Logger.Info("updated site ownership",
					slog.String("domain", farmSite.Name),
					slog.Int64("oldUserID", localSite.UserID),
					slog.Int64("newUserID", userID),
					slog.String("oldOwnerOIDC", currentOwnerOIDC),
					slog.String("newOwnerOIDC", ownerOIDCSubject))
			}
		}
	}

	// Remove sites from local database that no longer exist on the farm
	for _, localSite := range localSites {
		farmSite, exists := farmDomainMap[localSite.Domain]
		if !exists || farmSite.Status != "active" {
			// Site exists locally but not on farm (or is inactive) - remove it
			err := a.DB.DeleteSiteByDomain(ctx, localSite.Domain)
			if err != nil {
				a.Logger.Error("failed to delete site",
					slog.String("domain", localSite.Domain),
					slog.Any("error", err))
				continue
			}
			sitesRemoved++
			a.Logger.Info("removed site not on farm", slog.String("domain", localSite.Domain))
		}
	}

	a.Logger.Info("site sync completed",
		slog.Int("sitesAdded", sitesAdded),
		slog.Int("sitesUpdated", sitesUpdated),
		slog.Int("sitesRemoved", sitesRemoved))

	return &SyncSitesToDBOutput{
		SitesAdded:   sitesAdded,
		SitesUpdated: sitesUpdated,
		SitesRemoved: sitesRemoved,
	}, nil
}

// toNullString converts a string to sql.NullString
func toNullString(s string) sql.NullString {
	if s == "" {
		return sql.NullString{Valid: false}
	}
	return sql.NullString{String: s, Valid: true}
}

// fromNullString converts sql.NullString to string
func fromNullString(ns sql.NullString) string {
	if ns.Valid {
		return ns.String
	}
	return ""
}