package api

import (
	"net/http"
	"strconv"
)

// ocrWordResponse is the wire shape of one OCR word box. It is a dedicated DTO
// (not storage.OCRWord, which carries no json tags and exposes the internal row
// id / document_id) so the overlay renderer gets a compact, stable payload.
// Coordinates are in the original file's coordinate space — see
// internal/ocr/coords.go.
type ocrWordResponse struct {
	Text       string  `json:"text"`
	Left       int     `json:"left"`
	Top        int     `json:"top"`
	Width      int     `json:"width"`
	Height     int     `json:"height"`
	Confidence float64 `json:"confidence"`
	Page       int     `json:"page"`
	Block      int     `json:"block"`
	Par        int     `json:"par"`
	Line       int     `json:"line"`
}

// handleListDocumentOCRWords returns the stored word-level bounding boxes of a
// document (GET /api/documents/{id}/ocr-words), Phase 3 of the OCR
// text-highlight/overlay feature.
//
// Tenant/ACL: ocr_words has no tenant_id column, access is only ever mediated
// through document_id. The handler therefore performs the exact same ownership
// check as handleDocumentAuditLog / handleGetDocumentFile — GetDocument(id,
// tenantID) filters WHERE tenant_id and yields 404 for both "unknown id" and
// "foreign tenant", so the endpoint never reveals whether a document exists
// outside the caller's tenant — BEFORE any ocr_words row is read.
//
// Pure read: no audit entry, consistent with the other document GET handlers.
// Empty result serializes as [] (never null).
func (s *Server) handleListDocumentOCRWords(w http.ResponseWriter, r *http.Request) {
	sess := sessionFromCtx(r.Context())
	id, err := strconv.ParseInt(r.PathValue("id"), 10, 64)
	if err != nil || sess.TenantID == nil {
		writeError(w, http.StatusBadRequest, "invalid document id")
		return
	}
	// ACL/tenant check first — must precede the ocr_words lookup.
	if _, err := s.store.GetDocument(r.Context(), id, *sess.TenantID); err != nil {
		writeError(w, http.StatusNotFound, "document not found")
		return
	}

	words, err := s.store.ListOCRWords(r.Context(), id)
	if err != nil {
		s.reqLog(r.Context()).Error("list ocr words failed", "document_id", id, "tenant_id", *sess.TenantID, "err", err)
		writeError(w, http.StatusInternalServerError, "list ocr words failed")
		return
	}

	out := make([]ocrWordResponse, 0, len(words))
	for _, wd := range words {
		out = append(out, ocrWordResponse{
			Text:       wd.Word,
			Left:       wd.Left,
			Top:        wd.Top,
			Width:      wd.Width,
			Height:     wd.Height,
			Confidence: wd.Confidence,
			Page:       wd.Page,
			Block:      wd.Block,
			Par:        wd.Par,
			Line:       wd.Line,
		})
	}
	writeJSON(w, http.StatusOK, out)
}