package server

import (
	"encoding/base64"
	"fmt"
	"net/http"
	"path/filepath"
	"strconv"

	"git.mchus.pro/mchus/logpile/internal/sanitize"
)

// sanitizeArtifact holds the de-identified copy of the current upload, ready for
// download. Kept in memory only, like convertOutput.
type sanitizeArtifact struct {
	Data     []byte
	Filename string
}

func (s *Server) setSanitizeArtifact(a *sanitizeArtifact) {
	s.mu.Lock()
	s.sanitizeResult = a
	s.mu.Unlock()
}

func (s *Server) getSanitizeArtifact() *sanitizeArtifact {
	s.mu.RLock()
	defer s.mu.RUnlock()
	return s.sanitizeResult
}

// handleSanitize builds a de-identified copy of the retained original upload and
// returns the change preview. The file itself is fetched from GET /api/sanitize/download.
func (s *Server) handleSanitize(w http.ResponseWriter, r *http.Request) {
	pkg := s.GetRawExport()
	if pkg == nil || pkg.Source.Kind != "file_bytes" {
		jsonError(w, "sanitize is only available for an uploaded archive or log file", http.StatusUnprocessableEntity)
		return
	}
	if !sanitize.CanSanitize(pkg.Source.Filename) {
		jsonError(w, "this file format cannot be sanitized in place", http.StatusUnprocessableEntity)
		return
	}
	data, err := base64.StdEncoding.DecodeString(pkg.Source.Data)
	if err != nil {
		jsonError(w, "cannot read the original file bytes", http.StatusInternalServerError)
		return
	}

	res, err := sanitize.Sanitize(pkg.Source.Filename, data)
	if err != nil {
		jsonError(w, "sanitize failed: "+err.Error(), http.StatusUnprocessableEntity)
		return
	}

	s.setSanitizeArtifact(&sanitizeArtifact{Data: res.Data, Filename: pkg.Source.Filename})

	jsonResponse(w, map[string]any{
		"filename":       filepath.Base(pkg.Source.Filename),
		"input_size":     len(data),
		"output_size":    len(res.Data),
		"total_replaced": res.TotalReplaced,
		"changes":        res.Changes,
		"skipped_binary": res.SkippedBinary,
	})
}

func (s *Server) handleSanitizeDownload(w http.ResponseWriter, r *http.Request) {
	art := s.getSanitizeArtifact()
	if art == nil {
		jsonError(w, "no sanitized file ready; run POST /api/sanitize first", http.StatusNotFound)
		return
	}
	// Always octet-stream so the browser saves rather than renders it.
	w.Header().Set("Content-Type", "application/octet-stream")
	w.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=%q", filepath.Base(art.Filename)))
	w.Header().Set("Content-Length", strconv.Itoa(len(art.Data)))
	_, _ = w.Write(art.Data)
}