package api

import (
	"archive/zip"
	"bytes"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"regexp"
	"strings"
)

var slugSanitize = regexp.MustCompile(`[^a-zA-Z0-9._-]+`)

// sanitizeExportSlug lowercases and strips unsafe characters for filenames and campaign segments.
func sanitizeExportSlug(s string) string {
	s = strings.TrimSpace(s)
	s = strings.ToLower(s)
	s = slugSanitize.ReplaceAllString(s, "-")
	s = strings.Trim(s, "-.")
	if s == "" {
		return "site"
	}
	if len(s) > 48 {
		s = s[:48]
	}
	return s
}

// zipTemplateReplacements walks templateDir, applies repl to file contents, and writes a ZIP archive.
// remap rewrites archive entry paths (e.g. plugin-template → my-site).
func zipTemplateReplacements(templateDir string, repl map[string]string, remap func(rel string) string) ([]byte, error) {
	templateDir, err := filepath.Abs(templateDir)
	if err != nil {
		return nil, err
	}
	var buf bytes.Buffer
	zw := zip.NewWriter(&buf)
	err = filepath.Walk(templateDir, func(path string, info os.FileInfo, walkErr error) error {
		if walkErr != nil || info.IsDir() {
			return walkErr
		}
		rel, err := filepath.Rel(templateDir, path)
		if err != nil {
			return err
		}
		rel = filepath.ToSlash(rel)
		if remap != nil {
			rel = remap(rel)
		}
		data, err := os.ReadFile(path)
		if err != nil {
			return err
		}
		content := string(data)
		for k, v := range repl {
			content = strings.ReplaceAll(content, k, v)
		}
		w, err := zw.Create(rel)
		if err != nil {
			return err
		}
		_, err = io.WriteString(w, content)
		return err
	})
	if err != nil {
		return nil, err
	}
	if err := zw.Close(); err != nil {
		return nil, err
	}
	return buf.Bytes(), nil
}

func writeZipAttachment(w http.ResponseWriter, filename string, data []byte) {
	w.Header().Set("Content-Type", "application/zip")
	w.Header().Set("Content-Disposition", `attachment; filename="`+filename+`"`)
	w.Write(data)
}

func slugDisplayName(slug string) string {
	parts := strings.Split(slug, "-")
	for i, p := range parts {
		if p == "" {
			continue
		}
		parts[i] = strings.ToUpper(p[:1]) + p[1:]
	}
	return strings.Join(parts, " ")
}

func buildQuerySuffix(buildID, campaign string) (querySuffix, getQuerySuffix string) {
	var qparts []string
	if buildID != "" {
		qparts = append(qparts, "pin="+buildID)
	}
	if campaign != "" {
		qparts = append(qparts, "c="+campaign)
	}
	if len(qparts) == 0 {
		return "", ""
	}
	joined := strings.Join(qparts, "&")
	return "?" + joined, "&" + joined
}