package documenttext

import (
	"context"
	"fmt"
	"io"
	"log/slog"
	"strings"

	documenttypes "queryorchestration/internal/document/types"
)

func (s *Service) getDocumentText(ctx context.Context, doc documenttypes.File) (io.Reader, error) {
	pagesNum, err := doc.GetPageCount(ctx)
	if err != nil {
		return nil, err
	}

	group := s.cfg.GetThreadPool().NewGroup()

	textPages := make([]string, pagesNum)
	for i := range pagesNum {
		index := i
		group.SubmitErr(func() error {
			slog.Debug("extracting page text", "index", index)

			text, err := s.getPageText(ctx, doc, index)
			if err != nil {
				slog.Error("error extracting page text", "index", index, "error", err)
				return err
			}

			textPages[index] = text

			return nil
		})
	}

	err = group.Wait()
	if err != nil {
		return nil, err
	}

	text, err := s.mergeDocument(textPages)
	if err != nil {
		return nil, err
	}

	return text, nil
}

func (s *Service) mergeDocument(pages []string) (io.Reader, error) {
	var builder strings.Builder
	for i, page := range pages {
		builder.WriteString(fmt.Sprintf("Start of Page No. = %d\n\n", i+1))
		builder.WriteString(page)
		builder.WriteString("\n\n")
	}
	return strings.NewReader(builder.String()), nil
}