package meteo

import (
	"bytes"
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"log/slog"
	"net/http"
	"time"
)

type Handler struct {
	*Service
}

func NewHandler(service *Service) *Handler {
	return &Handler{
		Service: service,
	}
}

func (h *Handler) IngestCSV(w http.ResponseWriter, r *http.Request) {
	err := r.ParseMultipartForm(10 << 20)
	if err != nil {
		http.Error(w, ErrParsingForm.Error(), http.StatusBadRequest)
		return
	}

	file, header, err := r.FormFile("file")
	if err != nil {
		http.Error(w, ErrRetrievingFile.Error(), http.StatusBadRequest)
		return
	}
	defer file.Close()

	content, err := io.ReadAll(file)
	if err != nil {
		http.Error(w, ErrReadingFile.Error(), http.StatusInternalServerError)
		return
	}

	hash := sha256.Sum256(content)
	checksum := hex.EncodeToString(hash[:])

	fileStats := &FileStats{
		FileChecksum: checksum,
	}

	start := time.Now()
	err = h.Service.IngestCSV(r.Context(), bytes.NewReader(content), fileStats)
	if err != nil {
		slog.Error(ErrCannotParseFile.Error(),
			"filename", header.Filename,
			"error", err)
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	fileStats.ElapsedMS = int(time.Since(start).Milliseconds())
	h.UpdateElapsedMS(r.Context(), fileStats.BatchID, fileStats.ElapsedMS)

	slog.Info("CSV file processed",
		"filename", header.Filename,
		"rows_inserted", fileStats.RowsInserted,
		"rows_rejected", fileStats.RowsRejected,
		"elapsed_ms", fileStats.ElapsedMS,
		"file_checksum", fileStats.FileChecksum,
	)

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(H{
		"stats": fileStats,
	})
}

func (h *Handler) IngestExcel(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "hello from excel")
}