package handlers

import (
	"context"
	"net/http"
	"sort"
	"strconv"
	"time"

	"git.haelnorr.com/h/golib/hws"
	"git.haelnorr.com/h/oslstats/internal/auditlog"
	"git.haelnorr.com/h/oslstats/internal/db"
	"git.haelnorr.com/h/oslstats/internal/roles"
	"git.haelnorr.com/h/oslstats/internal/throw"
	"git.haelnorr.com/h/oslstats/internal/validation"
	adminview "git.haelnorr.com/h/oslstats/internal/view/adminview"
	"github.com/pkg/errors"
	"github.com/uptrace/bun"
)

// AdminRoles renders the full admin dashboard page with roles section
func AdminRoles(s *hws.Server, conn *bun.DB) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		var pageOpts *db.PageOpts
		if r.Method == "GET" {
			pageOpts = pageOptsFromQuery(s, w, r)
		} else {
			pageOpts = pageOptsFromForm(s, w, r)
		}
		if pageOpts == nil {
			return
		}

		var rolesList *db.List[db.Role]
		if ok := db.WithReadTx(s, w, r, conn, func(ctx context.Context, tx bun.Tx) (bool, error) {
			var err error
			rolesList, err = db.GetRoles(ctx, tx, pageOpts)
			if err != nil {
				return false, errors.Wrap(err, "db.GetRoles")
			}
			return true, nil
		}); !ok {
			return
		}

		if r.Method == "GET" {
			renderSafely(adminview.RolesPage(rolesList), s, r, w)
		} else {
			renderSafely(adminview.RolesList(rolesList), s, r, w)
		}
	})
}

// AdminRoleCreateForm shows the create role form modal
func AdminRoleCreateForm(s *hws.Server) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		renderSafely(adminview.RoleCreateForm(), s, r, w)
	})
}

// AdminRoleCreate creates a new role
func AdminRoleCreate(s *hws.Server, conn *bun.DB, audit *auditlog.Logger) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		getter, ok := validation.ParseFormOrNotify(s, w, r)
		if !ok {
			return
		}

		name := getter.String("name").Required().Value
		displayName := getter.String("display_name").Required().Value
		description := getter.String("description").Value

		if !getter.ValidateAndNotify(s, w, r) {
			return
		}

		pageOpts := pageOptsFromForm(s, w, r)
		if pageOpts == nil {
			return
		}

		var rolesList *db.List[db.Role]
		var newRole *db.Role
		if ok := db.WithNotifyTx(s, w, r, conn, func(ctx context.Context, tx bun.Tx) (bool, error) {
			newRole = &db.Role{
				Name:        roles.Role(name),
				DisplayName: displayName,
				Description: description,
				IsSystem:    false,
				CreatedAt:   time.Now().Unix(),
			}

			err := db.Insert(tx, newRole).WithAudit(r, audit.Callback()).Exec(ctx)
			if err != nil {
				return false, errors.Wrap(err, "db.Insert")
			}

			rolesList, err = db.GetRoles(ctx, tx, pageOpts)
			if err != nil {
				return false, errors.Wrap(err, "db.GetRoles")
			}

			return true, nil
		}); !ok {
			return
		}

		renderSafely(adminview.RolesList(rolesList), s, r, w)
	})
}

// AdminRoleManage shows the role management modal with details and actions
func AdminRoleManage(s *hws.Server, conn *bun.DB) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		roleIDStr := r.PathValue("id")
		roleID, err := strconv.Atoi(roleIDStr)
		if err != nil {
			w.WriteHeader(http.StatusBadRequest)
			return
		}

		var role *db.Role
		if ok := db.WithNotifyTx(s, w, r, conn, func(ctx context.Context, tx bun.Tx) (bool, error) {
			var err error
			role, err = db.GetRoleByID(ctx, tx, roleID)
			if err != nil {
				return false, errors.Wrap(err, "db.GetRoleByID")
			}
			if role == nil {
				return false, errors.New("role not found")
			}
			return true, nil
		}); !ok {
			return
		}

		renderSafely(adminview.RoleManageModal(role), s, r, w)
	})
}

// AdminRoleDeleteConfirm shows the delete confirmation dialog
func AdminRoleDeleteConfirm(s *hws.Server, conn *bun.DB) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		roleIDStr := r.PathValue("id")
		roleID, err := strconv.Atoi(roleIDStr)
		if err != nil {
			w.WriteHeader(http.StatusBadRequest)
			return
		}

		var role *db.Role
		if ok := db.WithNotifyTx(s, w, r, conn, func(ctx context.Context, tx bun.Tx) (bool, error) {
			var err error
			role, err = db.GetRoleByID(ctx, tx, roleID)
			if err != nil {
				return false, errors.Wrap(err, "db.GetRoleByID")
			}
			if role == nil {
				return false, errors.New("role not found")
			}
			return true, nil
		}); !ok {
			return
		}

		renderSafely(adminview.ConfirmDeleteRole(roleID, role.DisplayName), s, r, w)
	})
}

// AdminRoleDelete deletes a role
func AdminRoleDelete(s *hws.Server, conn *bun.DB, audit *auditlog.Logger) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		roleIDStr := r.PathValue("id")
		roleID, err := strconv.Atoi(roleIDStr)
		if err != nil {
			w.WriteHeader(http.StatusBadRequest)
			return
		}

		pageOpts := pageOptsFromForm(s, w, r)
		if pageOpts == nil {
			return
		}

		var rolesList *db.List[db.Role]
		if ok := db.WithNotifyTx(s, w, r, conn, func(ctx context.Context, tx bun.Tx) (bool, error) {
			// First check if role exists and get its details
			role, err := db.GetRoleByID(ctx, tx, roleID)
			if err != nil {
				return false, errors.Wrap(err, "db.GetRoleByID")
			}
			if role == nil {
				return false, errors.New("role not found")
			}

			// Check if it's a system role
			if role.IsSystem {
				return false, errors.New("cannot delete system roles")
			}

			// Delete the role with audit logging
			err = db.DeleteByID[db.Role](tx, roleID).WithAudit(r, audit.Callback()).Delete(ctx)
			if err != nil {
				return false, errors.Wrap(err, "db.DeleteByID")
			}

			// Reload roles
			rolesList, err = db.GetRoles(ctx, tx, pageOpts)
			if err != nil {
				return false, errors.Wrap(err, "db.GetRoles")
			}

			return true, nil
		}); !ok {
			return
		}

		renderSafely(adminview.RolesList(rolesList), s, r, w)
	})
}

// AdminRolePermissionsModal shows the permissions management modal for a role
func AdminRolePermissionsModal(s *hws.Server, conn *bun.DB) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		roleIDStr := r.PathValue("id")
		roleID, err := strconv.Atoi(roleIDStr)
		if err != nil {
			w.WriteHeader(http.StatusBadRequest)
			return
		}

		var role *db.Role
		var allPermissions []*db.Permission
		var groupedPerms []adminview.PermissionsByResource
		var rolePermIDs map[int]bool

		if ok := db.WithNotifyTx(s, w, r, conn, func(ctx context.Context, tx bun.Tx) (bool, error) {
			// Load role with permissions
			var err error
			role, err = db.GetRoleWithPermissions(ctx, tx, roleID)
			if err != nil {
				return false, errors.Wrap(err, "db.GetRoleWithPermissions")
			}
			if role == nil {
				return false, errors.New("role not found")
			}

			// Load all permissions
			allPermissions, err = db.ListAllPermissions(ctx, tx)
			if err != nil {
				return false, errors.Wrap(err, "db.ListAllPermissions")
			}
			return true, nil
		}); !ok {
			return
		}

		// Group permissions by resource
		permsByResource := make(map[string][]*db.Permission)
		for _, perm := range allPermissions {
			permsByResource[perm.Resource] = append(permsByResource[perm.Resource], perm)
		}

		// Convert to sorted slice
		for resource, perms := range permsByResource {
			groupedPerms = append(groupedPerms, adminview.PermissionsByResource{
				Resource:    resource,
				Permissions: perms,
			})
		}
		sort.Slice(groupedPerms, func(i, j int) bool {
			return groupedPerms[i].Resource < groupedPerms[j].Resource
		})

		// Create map of current role permissions for checkbox state
		rolePermIDs = make(map[int]bool)
		for _, perm := range role.Permissions {
			rolePermIDs[perm.ID] = true
		}

		renderSafely(adminview.RolePermissionsModal(role, groupedPerms, rolePermIDs), s, r, w)
	})
}

// AdminRolePermissionsUpdate updates the permissions for a role
func AdminRolePermissionsUpdate(s *hws.Server, conn *bun.DB, audit *auditlog.Logger) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		roleIDStr := r.PathValue("id")
		roleID, err := strconv.Atoi(roleIDStr)
		if err != nil {
			w.WriteHeader(http.StatusBadRequest)
			return
		}
		user := db.CurrentUser(r.Context())

		getter, ok := validation.ParseFormOrNotify(s, w, r)
		if !ok {
			return
		}

		// Get selected permission IDs from form
		permissionIDs := getter.IntList("permission_ids").Values()
		if !getter.ValidateAndNotify(s, w, r) {
			return
		}

		selectedPermIDs := make(map[int]bool)
		for _, id := range permissionIDs {
			selectedPermIDs[id] = true
		}

		pageOpts := pageOptsFromForm(s, w, r)
		if pageOpts == nil {
			return
		}

		var rolesList *db.List[db.Role]
		if ok := db.WithWriteTx(s, w, r, conn, func(ctx context.Context, tx bun.Tx) (bool, error) {
			// Get role with current permissions
			role, err := db.GetRoleWithPermissions(ctx, tx, roleID)
			if err != nil {
				return false, errors.Wrap(err, "db.GetRoleWithPermissions")
			}
			if role == nil {
				throw.NotFound(s, w, r, "Role not found")
				return false, nil
			}

			// Get all permissions to know what exists
			allPermissions, err := db.ListAllPermissions(ctx, tx)
			if err != nil {
				return false, errors.Wrap(err, "db.ListAllPermissions")
			}

			// Build map of current permissions
			currentPermIDs := make(map[int]bool)
			for _, perm := range role.Permissions {
				currentPermIDs[perm.ID] = true
			}

			var addedPerms []string
			var removedPerms []string

			// Determine what to add and remove
			for _, perm := range allPermissions {
				hasNow := currentPermIDs[perm.ID]
				shouldHave := selectedPermIDs[perm.ID]

				if shouldHave && !hasNow {
					// Add permission
					err := db.AddPermissionToRole(ctx, tx, roleID, perm.ID)
					if err != nil {
						return false, errors.Wrap(err, "db.AddPermissionToRole")
					}
					addedPerms = append(addedPerms, string(perm.Name))
				} else if !shouldHave && hasNow {
					// Remove permission
					err := db.RemovePermissionFromRole(ctx, tx, roleID, perm.ID)
					if err != nil {
						return false, errors.Wrap(err, "db.RemovePermissionFromRole")
					}
					removedPerms = append(removedPerms, string(perm.Name))
				}
			}

			// Log the permission changes
			if len(addedPerms) > 0 || len(removedPerms) > 0 {
				details := map[string]any{
					"role_name": string(role.Name),
				}
				if len(addedPerms) > 0 {
					details["added_permissions"] = addedPerms
				}
				if len(removedPerms) > 0 {
					details["removed_permissions"] = removedPerms
				}
				err = audit.LogSuccess(ctx, tx, user, "update", "role_permissions", roleID, details, r)
				if err != nil {
					return false, errors.Wrap(err, "audit.LogSuccess")
				}
			}

			// Reload roles
			rolesList, err = db.GetRoles(ctx, tx, pageOpts)
			if err != nil {
				return false, errors.Wrap(err, "db.GetRoles")
			}

			return true, nil
		}); !ok {
			return
		}

		renderSafely(adminview.RolesList(rolesList), s, r, w)
	})
}