package repository

import (
	"sort"
	"time"

	"gorm.io/gorm"
	"gorm.io/gorm/clause"
	"yingce/backend/internal/model"
)

func (r *Repository) UpsertCloudAgentResourceLeases(userID, runID, ownerID string, resourceIDs []string, expiresAt time.Time) error {
	resourceIDs = uniqueSortedStrings(resourceIDs)
	for _, id := range resourceIDs {
		lease := model.CloudAgentResourceLease{UserID: userID, RunID: runID, OwnerID: ownerID, ResourceID: id, ExpiresAt: expiresAt}
		if err := r.db.Clauses(clause.OnConflict{Columns: []clause.Column{{Name: "user_id"}, {Name: "owner_id"}, {Name: "resource_id"}}, DoUpdates: clause.AssignmentColumns([]string{"run_id", "expires_at"})}).Create(&lease).Error; err != nil {
			return err
		}
	}
	return nil
}

// ReplaceCloudAgentResourceLeases makes an approval owner's resource set
// authoritative after the user changes generation settings.
func (r *Repository) ReplaceCloudAgentResourceLeases(userID, runID, ownerID string, resourceIDs []string, expiresAt time.Time) error {
	return r.db.Transaction(func(tx *gorm.DB) error {
		if err := tx.Where("user_id = ? AND owner_id = ?", userID, ownerID).Delete(&model.CloudAgentResourceLease{}).Error; err != nil {
			return err
		}
		for _, id := range uniqueSortedStrings(resourceIDs) {
			lease := model.CloudAgentResourceLease{UserID: userID, RunID: runID, OwnerID: ownerID, ResourceID: id, ExpiresAt: expiresAt}
			if err := tx.Clauses(clause.OnConflict{Columns: []clause.Column{{Name: "user_id"}, {Name: "owner_id"}, {Name: "resource_id"}}, DoUpdates: clause.AssignmentColumns([]string{"run_id", "expires_at"})}).Create(&lease).Error; err != nil {
				return err
			}
		}
		return nil
	})
}

func (r *Repository) ReleaseCloudAgentResourceLeases(userID, ownerID string) error {
	return r.db.Where("user_id = ? AND owner_id = ?", userID, ownerID).Delete(&model.CloudAgentResourceLease{}).Error
}

func (r *Repository) ReleaseCloudAgentResourceLeasesByRun(userID, runID string) error {
	return r.db.Where("user_id = ? AND run_id = ?", userID, runID).Delete(&model.CloudAgentResourceLease{}).Error
}

func (r *Repository) TransferCloudAgentResourceLeases(userID, fromOwner, toOwner, runID string, expiresAt time.Time) error {
	if fromOwner == "" || toOwner == "" || fromOwner == toOwner {
		return nil
	}
	return r.db.Transaction(func(tx *gorm.DB) error {
		var leases []model.CloudAgentResourceLease
		if err := tx.Where("user_id = ? AND owner_id = ?", userID, fromOwner).Find(&leases).Error; err != nil {
			return err
		}
		if err := tx.Where("user_id = ? AND owner_id = ?", userID, toOwner).Delete(&model.CloudAgentResourceLease{}).Error; err != nil {
			return err
		}
		for _, lease := range leases {
			lease.OwnerID, lease.RunID, lease.ExpiresAt = toOwner, runID, expiresAt
			if err := tx.Clauses(clause.OnConflict{Columns: []clause.Column{{Name: "user_id"}, {Name: "owner_id"}, {Name: "resource_id"}}, DoUpdates: clause.AssignmentColumns([]string{"run_id", "expires_at"})}).Create(&lease).Error; err != nil {
				return err
			}
		}
		return tx.Where("user_id = ? AND owner_id = ?", userID, fromOwner).Delete(&model.CloudAgentResourceLease{}).Error
	})
}

func (r *Repository) ReleaseExpiredCloudAgentResourceLeases(now time.Time) error {
	return r.db.Where("expires_at <= ?", now).Delete(&model.CloudAgentResourceLease{}).Error
}

func uniqueSortedStrings(values []string) []string {
	seen := make(map[string]struct{}, len(values))
	result := make([]string, 0, len(values))
	for _, value := range values {
		if value == "" {
			continue
		}
		if _, ok := seen[value]; ok {
			continue
		}
		seen[value] = struct{}{}
		result = append(result, value)
	}
	sort.Strings(result)
	return result
}

func (r *Repository) CloudAgentCanvasMutationChain(userID, runID, canvasID string) ([]model.CloudAgentCanvasMutation, error) {
	var records []model.CloudAgentCanvasMutation
	err := r.db.Where("user_id = ? AND run_id = ? AND canvas_id = ? AND status IN ?", userID, runID, canvasID, []string{"applied", "not_undoable"}).Order("created_at, id").Find(&records).Error
	return records, err
}

// LatestCloudAgentCanvasMutationForCanvas is used to distinguish a current-run
// write from a later Agent run write. Manual canvas edits have no mutation row;
// comparing the row's after hash with the live document then rejects them too.
func (r *Repository) LatestCloudAgentCanvasMutationForCanvas(userID, canvasID string) (*model.CloudAgentCanvasMutation, error) {
	var mutation model.CloudAgentCanvasMutation
	err := r.db.Where("user_id = ? AND canvas_id = ? AND status IN ?", userID, canvasID, []string{"applied", "not_undoable"}).Order("created_at DESC, id DESC").First(&mutation).Error
	return &mutation, err
}