package capture

import (
	"fmt"
	"mime"
	"net/http"
	"os"
	"path/filepath"
	"strings"
	"sync/atomic"
	"time"

	"git.gulenok.ru/greenhaze/gaslight/internal/domain"
)

type ImageSaver struct {
	outputDir string
	counter   uint64
}

func NewImageSaver(outputDir string) *ImageSaver {
	return &ImageSaver{outputDir: outputDir}
}

func (s *ImageSaver) Save(resp *http.Response, body []byte) error {
	n := atomic.AddUint64(&s.counter, 1)
	ts := time.Now().UTC().Format("20060102T150405.000000000Z")
	host := sanitizeName(domain.HostWithoutPort(resp.Request.Host))
	ext := imageExtension(resp.Header.Get("Content-Type"), resp.Request.URL.Path)
	name := fmt.Sprintf("%s_%06d_%s%s", ts, n, host, ext)
	return os.WriteFile(filepath.Join(s.outputDir, name), body, 0o644)
}

func IsImageResponse(contentType, path string) bool {
	if strings.HasPrefix(strings.ToLower(contentType), "image/") {
		return true
	}
	switch strings.ToLower(filepath.Ext(path)) {
	case ".jpg", ".jpeg", ".png", ".gif", ".bmp", ".webp", ".svg", ".ico", ".avif":
		return true
	default:
		return false
	}
}

func imageExtension(contentType, requestPath string) string {
	if ext := strings.ToLower(filepath.Ext(requestPath)); ext != "" && ext != "." {
		return ext
	}

	base := strings.ToLower(strings.TrimSpace(strings.Split(contentType, ";")[0]))
	if base != "" {
		if exts, err := mime.ExtensionsByType(base); err == nil && len(exts) > 0 {
			return exts[0]
		}
	}
	return ".img"
}

func sanitizeName(s string) string {
	s = strings.ToLower(strings.TrimSpace(s))
	if s == "" {
		return "unknown-host"
	}

	var b strings.Builder
	for _, r := range s {
		switch {
		case r >= 'a' && r <= 'z':
			b.WriteRune(r)
		case r >= '0' && r <= '9':
			b.WriteRune(r)
		case r == '.', r == '-', r == '_':
			b.WriteRune(r)
		default:
			b.WriteByte('_')
		}
	}
	return b.String()
}