package storage

import (
	"context"
	"errors"
	"fmt"
	"strings"
	"time"

	"github.com/jackc/pgx/v5/pgconn"
)

// ErrDuplicateContentHash is returned by CreateDocument when the tenant
// already has an (active) document with the same content_hash — the DB-level
// half of the duplicate-upload protection (see
// migrations/003_documents_unique_hash.sql). The upload handler translates
// this into an HTTP 409.
var ErrDuplicateContentHash = errors.New("storage: document with this content hash already exists for tenant")

// ErrDocumentNotFound is returned when a tenant-scoped document lookup/update
// affects zero rows (wrong id, wrong tenant, or already soft-deleted).
var ErrDocumentNotFound = errors.New("storage: document not found")

// Document is the core archivdms record: a stored, indexed, and (optionally)
// GoBD-retention-locked document. Unlike archivmail's `emails` table this is
// intentionally generic — it is not tied to any particular ingestion source.
//
// Source / SourceRef are nullable placeholders for a later, purely optional
// archivmail-pull importer (via archivmail's REST API) — no importer exists
// yet, these columns just reserve the shape.
type Document struct {
	ID            int64      `json:"id"`
	TenantID      int64      `json:"tenant_id"`
	Title         string     `json:"title"`
	DocType       string     `json:"doc_type,omitempty"`       // deprecated free-text, kept for Bestandsschutz
	Correspondent string     `json:"correspondent,omitempty"`  // deprecated free-text, kept for Bestandsschutz
	DocTypeID     *int64     `json:"doc_type_id,omitempty"`
	CorrespondentID *int64   `json:"correspondent_id,omitempty"`
	StoragePath   string     `json:"storage_path"`
	ContentHash   string     `json:"content_hash"`
	OCRText       string     `json:"ocr_text,omitempty"`
	RetainUntil   *time.Time `json:"retain_until,omitempty"`
	// DocumentDate is the recognised belegdatum (invoice/document date) parsed
	// from the OCR text at upload/reprocess time, if any. It is separate from
	// CreatedAt (the immutable scan/upload timestamp kept for GoBD
	// traceability) and drives the store/<tenant>/<yyyy>/<mm>/ archival path at
	// upload time. Nullable — nil when no plausible date was found in the text.
	DocumentDate  *time.Time `json:"document_date,omitempty"`
	// DocumentDateScore is the confidence (0.4-0.9 automatic, 1.0 = manually
	// confirmed by a user via PUT .../document-date) of DocumentDate, or nil
	// when DocumentDate itself is nil / unknown (pre-existing rows from before
	// this column existed). Intended as a quality gate for the future
	// Buchhaltungs-Pull-API (only Score >= 0.75 auto-pullable) — see
	// migrations/025_document_date_score.sql. Never backfilled for existing
	// rows; NULL correctly means "no known score", not "score 0".
	DocumentDateScore *float64 `json:"document_date_score,omitempty"`
	Source        string     `json:"source,omitempty"`     // e.g. "upload" | "archivmail_import"
	SourceRef     string     `json:"source_ref,omitempty"` // external ref, e.g. archivmail mail ID
	CreatedBy     *int64     `json:"created_by,omitempty"`
	// TitleManuallySet is true once a user has explicitly renamed the document
	// via PATCH /api/documents/{id} (handleUpdateDocumentTitle). It gates
	// whether POST .../reprocess is allowed to overwrite the title with a
	// freshly re-derived one — see UpdateDocumentTitleAuto.
	TitleManuallySet bool      `json:"title_manually_set"`
	// HasThumbnail is true once an eager preview thumbnail has been rendered
	// for this document (at upload or reprocess time, see internal/api
	// storeUploadedFile / ReprocessDocument) to
	// config.StorageConfig.ThumbnailPath()/<tenant>/<hash>.png. False for
	// documents whose thumbnail render failed/was skipped (unsupported
	// format, missing generator) or for any pre-existing document from before
	// this column existed — GET /api/documents/{id}/thumbnail still falls
	// back to on-demand lazy generation regardless of this flag, so a false
	// value never hard-blocks the preview, it's purely an optimisation hint.
	HasThumbnail  bool       `json:"has_thumbnail"`
	// ProcessingStatus spiegelt den Zustand der asynchronen Nachverarbeitung
	// (OCR/Taxonomie/Workflows) wider: queued | processing | done | failed
	// (siehe processing_jobs.go). Altbestand steht per Spalten-Default auf
	// 'done'. ACHTUNG: nur die Abfragen in dieser Datei (CreateDocument*,
	// GetDocument, ListDocuments) füllen das Feld — andere Selects (Suche,
	// Papierkorb, Retention) lassen es leer; "" ist vom Frontend wie 'done'
	// zu behandeln.
	ProcessingStatus string  `json:"processing_status,omitempty"`
	CreatedAt     time.Time  `json:"created_at"`
	UpdatedAt     time.Time  `json:"updated_at"`
}

// CreateDocumentRequest holds parameters for creating a new document.
type CreateDocumentRequest struct {
	TenantID      int64
	Title         string
	DocType       string
	Correspondent string
	StoragePath   string
	ContentHash   string
	OCRText       string
	RetainUntil   *time.Time
	// DocumentDate is the recognised belegdatum from the OCR text (nil if none).
	DocumentDate  *time.Time
	// DocumentDateScore is the confidence for DocumentDate, mirrors the field
	// on Document (nil if DocumentDate is nil / unknown).
	DocumentDateScore *float64
	Source        string
	SourceRef     string
	// CreatedBy is the uploading user's ID, if known (nil for non-interactive
	// sources like the SFTP watcher). Used so an uploader can always see
	// their own document even before any permission-group grant exists for
	// it — otherwise a plain 'user' role could upload a document and
	// immediately lose visibility of it (see RecomputeVisibility/ACL model).
	CreatedBy *int64
}

func (s *Store) initSchema(ctx context.Context) error {
	_, err := s.db.Exec(ctx, `
		CREATE TABLE IF NOT EXISTS documents (
			id            BIGSERIAL PRIMARY KEY,
			tenant_id     BIGINT NOT NULL,
			title         TEXT NOT NULL,
			doc_type      TEXT,
			correspondent TEXT,
			storage_path  TEXT NOT NULL,
			content_hash  TEXT NOT NULL,
			ocr_text      TEXT,
			retain_until  DATE,
			created_at    TIMESTAMPTZ NOT NULL DEFAULT now(),
			updated_at    TIMESTAMPTZ NOT NULL DEFAULT now()
		);
		CREATE INDEX IF NOT EXISTS idx_documents_tenant ON documents(tenant_id);
	`)
	if err != nil {
		return fmt.Errorf("storage: create documents table: %w", err)
	}

	// Duplicate protection at the DB level, on top of the filesystem-level
	// collision check performed by the upload handler (see
	// migrations/003_documents_unique_hash.sql).
	_, err = s.db.Exec(ctx, `
		CREATE UNIQUE INDEX IF NOT EXISTS idx_documents_tenant_hash ON documents(tenant_id, content_hash);
	`)
	if err != nil {
		return fmt.Errorf("storage: create documents unique hash index: %w", err)
	}

	// Space for a later, optional archivmail-pull importer (see Document doc
	// comment). Added as nullable columns now, idempotently, no importer yet.
	_, err = s.db.Exec(ctx, `
		ALTER TABLE documents ADD COLUMN IF NOT EXISTS source TEXT;
		ALTER TABLE documents ADD COLUMN IF NOT EXISTS source_ref TEXT;
	`)
	if err != nil {
		return fmt.Errorf("storage: alter documents table: %w", err)
	}

	// created_by: nullable, no FK (users can be deleted independently of
	// their historical uploads, same Bestandsschutz reasoning as elsewhere
	// in this schema). Lets ListDocuments always show the uploader their own
	// document even with zero document_visibility rows (see CreateDocumentRequest).
	_, err = s.db.Exec(ctx, `
		ALTER TABLE documents ADD COLUMN IF NOT EXISTS created_by BIGINT;
	`)
	if err != nil {
		return fmt.Errorf("storage: alter documents add created_by: %w", err)
	}

	// title_manually_set: tracks whether a user has explicitly renamed the
	// document (via PATCH .../title) versus the title still being whatever was
	// auto-derived from OCR text at upload time. Reprocess only re-derives the
	// title from fresh OCR when this is false, so a user's manual rename is
	// never silently overwritten. Defaults to false for all existing rows —
	// deliberate: we cannot distinguish old manual renames from old
	// auto-derived titles, and false is the safe choice that lets reprocess
	// improve stale/garbled auto-derived titles from before the OCR
	// rotation/deskew fix (see DEVLOG).
	_, err = s.db.Exec(ctx, `
		ALTER TABLE documents ADD COLUMN IF NOT EXISTS title_manually_set BOOLEAN NOT NULL DEFAULT false;
	`)
	if err != nil {
		return fmt.Errorf("storage: alter documents add title_manually_set: %w", err)
	}

	// document_date: the belegdatum (invoice/document date) recognised from the
	// OCR text, separate from created_at (the immutable scan/upload timestamp).
	// Nullable — nil for existing rows and for documents where no plausible date
	// was found. Drives the store/<tenant>/<yyyy>/<mm>/ archival path at upload
	// time (see internal/api storeUploadedFile); reprocess refreshes the column
	// but never moves the already-archived WORM file. See
	// migrations/019_document_date.sql.
	_, err = s.db.Exec(ctx, `
		ALTER TABLE documents ADD COLUMN IF NOT EXISTS document_date DATE;
	`)
	if err != nil {
		return fmt.Errorf("storage: alter documents add document_date: %w", err)
	}

	// document_date_score: confidence (0.4-0.9 automatic keyword-proximity
	// heuristic, 1.0 once a user manually confirms/overrides the date via PUT
	// .../document-date) for document_date. Nullable, no backfill for existing
	// rows — NULL means "score unknown", not "score 0". Reserved as a quality
	// gate for the future Buchhaltungs-Pull-API (only Score >= 0.75 pullable).
	// See migrations/025_document_date_score.sql.
	_, err = s.db.Exec(ctx, `
		ALTER TABLE documents ADD COLUMN IF NOT EXISTS document_date_score NUMERIC;
	`)
	if err != nil {
		return fmt.Errorf("storage: alter documents add document_date_score: %w", err)
	}

	// Structured taxonomy entities (tags/document_types/correspondents) plus
	// the barcode-recognition columns on documents (see
	// migrations/005_taxonomy.sql / lazy-splashing-puppy plan).
	if err := s.initTaxonomySchema(ctx); err != nil {
		return err
	}

	// Custom fields (custom_field_defs / document_type_fields /
	// document_field_values — see migrations/006_custom_fields.sql).
	if err := s.initCustomFieldsSchema(ctx); err != nil {
		return err
	}

	// Papierkorb + gestaffeltes Löschkonzept (soft-delete + Vier-Augen-Prinzip
	// für finales Löschen — see migrations/007_trash.sql).
	if err := s.initTrashSchema(ctx); err != nil {
		return err
	}

	// Klassifizierungsvorlagen (classification templates — see
	// migrations/011_classification_templates.sql). Depends on document_types
	// (initTaxonomySchema) and custom_field_defs (initCustomFieldsSchema)
	// created above, so it is wired in AFTER them.
	if err := s.initClassificationTemplatesSchema(ctx); err != nil {
		return err
	}

	// Workflows / Consumption-Regeln (see migrations/012_workflows.sql). Wired
	// in AFTER classification templates because a workflow action can reference
	// a classification template (apply_classification_template).
	if err := s.initWorkflowsSchema(ctx); err != nil {
		return err
	}

	// Heuristische Metadaten-Vorschläge (metadata_suggestions — see
	// migrations/012_metadata_suggestions.sql). Wired in AFTER documents/taxonomy
	// exist, since suggestions score taxonomy entities against a document.
	if err := s.initMetadataSuggestionsSchema(ctx); err != nil {
		return err
	}

	// Pro-Mandant konfigurierbare Anbindung an einen EXTERNEN Ollama-Server
	// (tenant_ollama_config — see migrations/017_tenant_ollama_config.sql).
	// Gate für den optionalen 'ollama'-Provider der Metadaten-Vorschläge.
	if err := s.initOllamaConfigSchema(ctx); err != nil {
		return err
	}

	// Freitext-Notizen pro Dokument (document_notes — see
	// migrations/013_document_notes.sql). Wired in AFTER documents exists since
	// it FK-references documents(id).
	if err := s.initDocumentNotesSchema(ctx); err != nil {
		return err
	}

	// Gespeicherte Suchansichten (saved_views — SavedViews, Paperless-ngx
	// inspiriert). Tenant-/user-scoped, hängt an keiner anderen Tabelle, daher
	// zuletzt eingehängt.
	if err := s.initSavedViewsSchema(ctx); err != nil {
		return err
	}

	// OCR-Wortpositionen (ocr_words — see migrations/024_ocr_words.sql), Phase
	// 2 of the OCR text-highlight/overlay feature. Wired in AFTER documents
	// exists since it FK-references documents(id) ON DELETE CASCADE.
	if err := s.initOCRWordsSchema(ctx); err != nil {
		return err
	}

	// Digitale Akten (digitaler Aktenordner — see
	// migrations/018_akten.sql / project_akte_konzept_plan.md). Wired in AFTER
	// documents + correspondents exist: initAktenSchema creates the akten table
	// (FK to correspondents) and then ALTERs documents to add akte_id (FK to
	// akten), so both referenced tables must already exist.
	if err := s.initAktenSchema(ctx); err != nil {
		return err
	}

	// ML-Retraining-Klassifizierung Phase 1 (Naive-Bayes, ergänzt die
	// Regel-Engine — see migrations/020_ml_classifier.sql). Wired in AFTER
	// initTaxonomySchema since it FK-references nothing directly but ALTERs
	// documents/document_tags which must already exist.
	if err := s.initMLClassifierSchema(ctx); err != nil {
		return err
	}

	// has_thumbnail: tracks whether an eager preview thumbnail was rendered at
	// upload/reprocess time (see storeUploadedFile/ReprocessDocument in
	// internal/api). Defaults to false for all existing rows — deliberate:
	// GET /api/documents/{id}/thumbnail already falls back to on-demand lazy
	// generation on a cache miss regardless of this flag (see
	// internal/thumbnail), so no backfill migration is needed here, this
	// column is purely a "was it pre-rendered" hint for the frontend.
	_, err = s.db.Exec(ctx, `
		ALTER TABLE documents ADD COLUMN IF NOT EXISTS has_thumbnail BOOLEAN NOT NULL DEFAULT false;
	`)
	if err != nil {
		return fmt.Errorf("storage: alter documents add has_thumbnail: %w", err)
	}

	// GoBD-Aufbewahrungsregeln (retention rules / "Disposition Schedules" —
	// see migrations/022_retention_rules.sql). Wired in AFTER initTaxonomySchema
	// (FK to document_types) and AFTER initTrashSchema (retain_until/deleted_at
	// on documents must already exist — the rules engine only ever FEEDS
	// retain_until, the existing trash + Vier-Augen flow performs the actual
	// disposition).
	if err := s.initRetentionRulesSchema(ctx); err != nil {
		return err
	}

	// Mandanten-Job-Queue für die asynchrone Nachverarbeitung (processing_jobs
	// + documents.processing_status — see migrations/023_processing_jobs.sql).
	// Zuletzt eingehängt: die Tabelle FK-referenziert documents(id), das muss
	// also bereits existieren.
	if err := s.initProcessingJobsSchema(ctx); err != nil {
		return err
	}
	return nil
}

// CreateDocument inserts a new document and returns it.
func (s *Store) CreateDocument(ctx context.Context, req CreateDocumentRequest) (*Document, error) {
	var d Document
	err := s.db.QueryRow(ctx, `
		INSERT INTO documents (tenant_id, title, doc_type, correspondent, storage_path, content_hash, ocr_text, retain_until, document_date, document_date_score, source, source_ref, created_by)
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13)
		RETURNING id, tenant_id, title, COALESCE(doc_type, ''), COALESCE(correspondent, ''), doc_type_id, correspondent_id, storage_path, content_hash,
			COALESCE(ocr_text, ''), retain_until, document_date, document_date_score, COALESCE(source, ''), COALESCE(source_ref, ''), created_by, title_manually_set, has_thumbnail, processing_status, created_at, updated_at
	`, req.TenantID, req.Title, nullIfEmpty(req.DocType), nullIfEmpty(req.Correspondent), req.StoragePath, req.ContentHash,
		nullIfEmpty(req.OCRText), req.RetainUntil, req.DocumentDate, req.DocumentDateScore, nullIfEmpty(req.Source), nullIfEmpty(req.SourceRef), req.CreatedBy,
	).Scan(&d.ID, &d.TenantID, &d.Title, &d.DocType, &d.Correspondent, &d.DocTypeID, &d.CorrespondentID, &d.StoragePath, &d.ContentHash,
		&d.OCRText, &d.RetainUntil, &d.DocumentDate, &d.DocumentDateScore, &d.Source, &d.SourceRef, &d.CreatedBy, &d.TitleManuallySet, &d.HasThumbnail, &d.ProcessingStatus, &d.CreatedAt, &d.UpdatedAt)
	if err != nil {
		var pgErr *pgconn.PgError
		if errors.As(err, &pgErr) && pgErr.Code == "23505" {
			return nil, ErrDuplicateContentHash
		}
		return nil, fmt.Errorf("storage: create document: %w", err)
	}
	return &d, nil
}

// GetDocument retrieves a document by ID, scoped to tenant.
func (s *Store) GetDocument(ctx context.Context, id, tenantID int64) (*Document, error) {
	var d Document
	err := s.db.QueryRow(ctx, `
		SELECT id, tenant_id, title, COALESCE(doc_type, ''), COALESCE(correspondent, ''), doc_type_id, correspondent_id, storage_path, content_hash,
			COALESCE(ocr_text, ''), retain_until, document_date, document_date_score, COALESCE(source, ''), COALESCE(source_ref, ''), created_by, title_manually_set, has_thumbnail, processing_status, created_at, updated_at
		FROM documents WHERE id = $1 AND tenant_id = $2
	`, id, tenantID).Scan(&d.ID, &d.TenantID, &d.Title, &d.DocType, &d.Correspondent, &d.DocTypeID, &d.CorrespondentID, &d.StoragePath, &d.ContentHash,
		&d.OCRText, &d.RetainUntil, &d.DocumentDate, &d.DocumentDateScore, &d.Source, &d.SourceRef, &d.CreatedBy, &d.TitleManuallySet, &d.HasThumbnail, &d.ProcessingStatus, &d.CreatedAt, &d.UpdatedAt)
	if err != nil {
		return nil, fmt.Errorf("storage: get document: %w", err)
	}
	return &d, nil
}

// DocumentExistsByHash reports whether the tenant already has a document with
// the given content_hash. This mirrors the (tenant_id, content_hash) unique
// index (deleted_at is intentionally NOT filtered, so the result matches what
// CreateDocument's INSERT would enforce) and lets the upload pipeline detect a
// duplicate BEFORE spending OCR/Tesseract cycles on the file.
func (s *Store) DocumentExistsByHash(ctx context.Context, tenantID int64, contentHash string) (bool, error) {
	var exists bool
	err := s.db.QueryRow(ctx, `
		SELECT EXISTS (SELECT 1 FROM documents WHERE tenant_id = $1 AND content_hash = $2)
	`, tenantID, contentHash).Scan(&exists)
	if err != nil {
		return false, fmt.Errorf("storage: check document hash: %w", err)
	}
	return exists, nil
}

// ListDocuments returns all documents for a tenant, newest first.
//
// aclUserID applies the group-resolved document ACL: when non-nil, only
// documents visible to that user via document_visibility (through their
// permission group memberships) are returned. Callers pass a non-nil value
// only for role 'user'; domain_admin/superadmin pass nil to see every document
// in the tenant unfiltered (roles remain the outer boundary — see
// permissions.go).
func (s *Store) ListDocuments(ctx context.Context, tenantID int64, aclUserID *int64) ([]Document, error) {
	rows, err := s.db.Query(ctx, `
		SELECT id, tenant_id, title, COALESCE(doc_type, ''), COALESCE(correspondent, ''), doc_type_id, correspondent_id, storage_path, content_hash,
			COALESCE(ocr_text, ''), retain_until, document_date, document_date_score, COALESCE(source, ''), COALESCE(source_ref, ''), created_by, title_manually_set, has_thumbnail, processing_status, created_at, updated_at
		FROM documents
		WHERE tenant_id = $1 AND deleted_at IS NULL
		  AND ($2::bigint IS NULL OR documents.created_by = $2 OR EXISTS (
			SELECT 1 FROM document_visibility dv
			JOIN permission_group_members pgm ON pgm.group_id = dv.group_id
			WHERE dv.document_id = documents.id AND pgm.user_id = $2
		  ))
		ORDER BY created_at DESC
	`, tenantID, aclUserID)
	if err != nil {
		return nil, fmt.Errorf("storage: list documents: %w", err)
	}
	defer rows.Close()

	out := make([]Document, 0)
	for rows.Next() {
		var d Document
		if err := rows.Scan(&d.ID, &d.TenantID, &d.Title, &d.DocType, &d.Correspondent, &d.DocTypeID, &d.CorrespondentID, &d.StoragePath, &d.ContentHash,
			&d.OCRText, &d.RetainUntil, &d.DocumentDate, &d.DocumentDateScore, &d.Source, &d.SourceRef, &d.CreatedBy, &d.TitleManuallySet, &d.HasThumbnail, &d.ProcessingStatus, &d.CreatedAt, &d.UpdatedAt); err != nil {
			return nil, fmt.Errorf("storage: scan document: %w", err)
		}
		out = append(out, d)
	}
	return out, rows.Err()
}

// IsDocumentVisible reports whether the given user may see the document, using
// exactly the same rule as ListDocuments' ACL predicate (own upload OR a
// document_visibility row resolved through the user's permission groups).
// Always tenant-scoped: a document of another tenant is never visible, even to
// its own uploader. Callers pass userID only for role 'user'; domain_admin /
// superadmin skip this check (roles remain the outer ACL boundary).
func (s *Store) IsDocumentVisible(ctx context.Context, id, tenantID, userID int64) (bool, error) {
	var visible bool
	err := s.db.QueryRow(ctx, `
		SELECT EXISTS (
			SELECT 1 FROM documents d
			WHERE d.id = $1 AND d.tenant_id = $2 AND d.deleted_at IS NULL
			  AND (d.created_by = $3 OR EXISTS (
				SELECT 1 FROM document_visibility dv
				JOIN permission_group_members pgm ON pgm.group_id = dv.group_id
				WHERE dv.document_id = d.id AND pgm.user_id = $3
			  ))
		)
	`, id, tenantID, userID).Scan(&visible)
	if err != nil {
		return false, fmt.Errorf("storage: check document visibility: %w", err)
	}
	return visible, nil
}

// DocumentTaxonomyNames resolves the structured document-type and correspondent
// names of a document, tenant-scoped. Empty strings when unassigned. Used by
// the single-document export (metadata.json) so the ZIP carries readable names
// instead of raw IDs.
func (s *Store) DocumentTaxonomyNames(ctx context.Context, id, tenantID int64) (docType, correspondent string, err error) {
	err = s.db.QueryRow(ctx, `
		SELECT COALESCE(dt.name, ''), COALESCE(c.name, '')
		FROM documents d
		LEFT JOIN document_types dt ON dt.id = d.doc_type_id AND dt.tenant_id = d.tenant_id
		LEFT JOIN correspondents  c ON c.id  = d.correspondent_id AND c.tenant_id = d.tenant_id
		WHERE d.id = $1 AND d.tenant_id = $2
	`, id, tenantID).Scan(&docType, &correspondent)
	if err != nil {
		return "", "", fmt.Errorf("storage: document taxonomy names: %w", err)
	}
	return docType, correspondent, nil
}

// UpdateDocumentTitle renames a document, scoped to tenant, and marks the
// title as manually set (title_manually_set = true). Use this for the
// user-facing PATCH .../title endpoint only — it permanently opts the
// document out of automatic title re-derivation by POST .../reprocess. Title
// is not part of the ACL, so this only needs an index re-sync (mirrors
// SetDocumentCorrespondent in taxonomy.go), not a visibility recompute.
func (s *Store) UpdateDocumentTitle(ctx context.Context, id, tenantID int64, title string) error {
	tag, err := s.db.Exec(ctx, `UPDATE documents SET title = $1, title_manually_set = true, updated_at = now() WHERE id = $2 AND tenant_id = $3`, title, id, tenantID)
	if err != nil {
		return fmt.Errorf("storage: update document title: %w", err)
	}
	if tag.RowsAffected() == 0 {
		return fmt.Errorf("storage: update document title: %w", ErrDocumentNotFound)
	}
	s.SyncIndex(ctx, id)
	return nil
}

// UpdateDocumentTitleAuto renames a document without touching
// title_manually_set. Used only by POST .../reprocess to re-derive a title
// from freshly re-extracted OCR text — callers must already have checked
// doc.TitleManuallySet is false before calling this, otherwise a user's
// manual rename would be silently overwritten.
func (s *Store) UpdateDocumentTitleAuto(ctx context.Context, id, tenantID int64, title string) error {
	tag, err := s.db.Exec(ctx, `UPDATE documents SET title = $1, updated_at = now() WHERE id = $2 AND tenant_id = $3`, title, id, tenantID)
	if err != nil {
		return fmt.Errorf("storage: update document title (auto): %w", err)
	}
	if tag.RowsAffected() == 0 {
		return fmt.Errorf("storage: update document title (auto): %w", ErrDocumentNotFound)
	}
	s.SyncIndex(ctx, id)
	return nil
}

// UpdateDocumentOCRText replaces a document's ocr_text, scoped to tenant.
// Used by the re-processing endpoint (POST /api/documents/{id}/reprocess)
// after re-running OCR on an already-archived file — the WORM file itself is
// never touched, only this derived metadata column is refreshed. OCR text is
// not part of the ACL, so this only needs an index re-sync (mirrors
// UpdateDocumentTitle), not a visibility recompute.
func (s *Store) UpdateDocumentOCRText(ctx context.Context, id, tenantID int64, ocrText string) error {
	tag, err := s.db.Exec(ctx, `UPDATE documents SET ocr_text = $1, updated_at = now() WHERE id = $2 AND tenant_id = $3`, nullIfEmpty(ocrText), id, tenantID)
	if err != nil {
		return fmt.Errorf("storage: update document ocr_text: %w", err)
	}
	if tag.RowsAffected() == 0 {
		return fmt.Errorf("storage: update document ocr_text: %w", ErrDocumentNotFound)
	}
	s.SyncIndex(ctx, id)
	return nil
}

// UpdateDocumentDate replaces a document's recognised belegdatum
// (document_date) and its confidence (document_date_score), scoped to tenant.
// Used by the re-processing endpoint after re-running OCR so the metadata
// reflects a freshly recognised date — the WORM file and its
// store/<yyyy>/<mm>/ path are NEVER moved, only this derived column is
// refreshed. Passing a nil date clears both date and score. score should be
// 1.0 when the caller is a manual user confirmation (PUT .../document-date),
// or the heuristic's own confidence (0.4-0.9) for automatic
// extract/reprocess/job-queue callers — never carry over a stale automatic
// score after a manual override. document_date is not part of the ACL, so
// this only needs an index re-sync (mirrors UpdateDocumentOCRText), not a
// visibility recompute.
func (s *Store) UpdateDocumentDate(ctx context.Context, id, tenantID int64, date *time.Time, score *float64) error {
	if date == nil {
		score = nil
	}
	tag, err := s.db.Exec(ctx, `UPDATE documents SET document_date = $1, document_date_score = $2, updated_at = now() WHERE id = $3 AND tenant_id = $4`, date, score, id, tenantID)
	if err != nil {
		return fmt.Errorf("storage: update document date: %w", err)
	}
	if tag.RowsAffected() == 0 {
		return fmt.Errorf("storage: update document date: %w", ErrDocumentNotFound)
	}
	s.SyncIndex(ctx, id)
	return nil
}

// SetDocumentHasThumbnail records whether an eager preview thumbnail was
// successfully rendered for this document, scoped to tenant. Used by
// storeUploadedFile (after upload) and ReprocessDocument (to backfill/repair
// a previously missing thumbnail) — see internal/api/document_handlers.go.
// has_thumbnail is a pure UI hint (not indexed content, not part of the ACL),
// so unlike UpdateDocumentTitle/OCRText/Date this deliberately does NOT call
// SyncIndex — no Manticore reindex is needed for a thumbnail flag.
func (s *Store) SetDocumentHasThumbnail(ctx context.Context, id, tenantID int64, hasThumbnail bool) error {
	tag, err := s.db.Exec(ctx, `UPDATE documents SET has_thumbnail = $1, updated_at = now() WHERE id = $2 AND tenant_id = $3`, hasThumbnail, id, tenantID)
	if err != nil {
		return fmt.Errorf("storage: set document has_thumbnail: %w", err)
	}
	if tag.RowsAffected() == 0 {
		return fmt.Errorf("storage: set document has_thumbnail: %w", ErrDocumentNotFound)
	}
	return nil
}

// DeleteDocument removes a document, scoped to tenant.
func (s *Store) DeleteDocument(ctx context.Context, id, tenantID int64) error {
	tag, err := s.db.Exec(ctx, `DELETE FROM documents WHERE id = $1 AND tenant_id = $2`, id, tenantID)
	if err != nil {
		return fmt.Errorf("storage: delete document: %w", err)
	}
	if tag.RowsAffected() == 0 {
		return fmt.Errorf("storage: document not found or not owned by tenant")
	}
	return nil
}

func nullIfEmpty(s string) any {
	if s == "" {
		return nil
	}
	return s
}

// nullIfEmptyPtr maps a *string to a NULL-able SQL argument: nil or a
// whitespace-only value becomes NULL, otherwise the trimmed string is stored.
func nullIfEmptyPtr(s *string) any {
	if s == nil {
		return nil
	}
	if strings.TrimSpace(*s) == "" {
		return nil
	}
	return strings.TrimSpace(*s)
}