package api

import (
	"errors"
	"net/http"
	"strconv"
	"strings"

	"archivdms/internal/auth"
	"archivdms/internal/index"
	"archivdms/internal/storage"
	"archivdms/internal/userstore"
)

// handleSearchDocuments serves GET /api/documents/search — full-text +
// attribute search backed by the per-tenant Manticore index.
//
//	q            full-text term (matched against title/ocr_text/tags/
//	             correspondent/doc_type). Optional; when empty the query
//	             degrades to a filter-only listing ordered by recency.
//	tag          repeatable tag id filter (documents carrying ANY given tag).
//	doc_type_id  restrict to a single document type.
//	page         1-based page number (default 1).
//	page_size    hits per page (default 20, capped at 100).
//
// ACL: role 'user' is filtered against their permission-group memberships
// (ANY(acl_group_ids)); domain_admin/superadmin bypass the ACL, exactly like
// handleListDocuments. When the search backend is not configured the endpoint
// returns 503 rather than a silent empty result.
func (s *Server) handleSearchDocuments(w http.ResponseWriter, r *http.Request) {
	sess := sessionFromCtx(r.Context())
	if sess.TenantID == nil {
		writeError(w, http.StatusForbidden, "tenant context required")
		return
	}
	tenantID := *sess.TenantID

	q := index.SearchQuery{
		Query:     strings.TrimSpace(r.URL.Query().Get("q")),
		Page:      parsePositiveInt(r.URL.Query().Get("page"), 1),
		PageSize:  clampInt(parsePositiveInt(r.URL.Query().Get("page_size"), 20), 1, 100),
		TagIDs:    parseInt64List(r.URL.Query()["tag"]),
		DocTypeID: parseOptionalInt64(r.URL.Query().Get("doc_type_id")),
	}

	// Roles are the outer ACL boundary (see handleListDocuments): role 'user'
	// is filtered against document_visibility via their group memberships;
	// domain_admin/superadmin see every document in the tenant (ACLGroupIDs nil).
	if !auth.HasRole(sess.Role, userstore.RoleDomainAdmin) {
		groupIDs, err := s.store.ListGroupIDsForUser(r.Context(), sess.UserID, tenantID)
		if err != nil {
			writeError(w, http.StatusInternalServerError, "search failed")
			return
		}
		// Non-nil (possibly empty) slice => ACL filter applies. An empty slice
		// means the user is in no group and therefore sees nothing.
		q.ACLGroupIDs = groupIDs
	}

	res, err := s.store.SearchDocuments(r.Context(), tenantID, q)
	if err != nil {
		if errors.Is(err, storage.ErrSearchUnavailable) {
			writeError(w, http.StatusServiceUnavailable, "Suche nicht verfügbar, Manticore nicht konfiguriert")
			return
		}
		writeError(w, http.StatusInternalServerError, "search failed")
		return
	}
	writeJSON(w, http.StatusOK, res)
}

// --- small query-param parsing helpers ---

func parsePositiveInt(s string, def int) int {
	if s == "" {
		return def
	}
	n, err := strconv.Atoi(s)
	if err != nil || n <= 0 {
		return def
	}
	return n
}

func clampInt(n, min, max int) int {
	if n < min {
		return min
	}
	if n > max {
		return max
	}
	return n
}

func parseOptionalInt64(s string) *int64 {
	if s == "" {
		return nil
	}
	n, err := strconv.ParseInt(s, 10, 64)
	if err != nil {
		return nil
	}
	return &n
}

// parseInt64List parses a slice of query values (each possibly comma-separated)
// into positive int64 ids, silently dropping anything unparseable.
func parseInt64List(vals []string) []int64 {
	var out []int64
	for _, v := range vals {
		for _, part := range strings.Split(v, ",") {
			part = strings.TrimSpace(part)
			if part == "" {
				continue
			}
			if n, err := strconv.ParseInt(part, 10, 64); err == nil && n > 0 {
				out = append(out, n)
			}
		}
	}
	return out
}