package app

import (
	"bytes"
	"fmt"
	"io"
	"log"
	"net/http"
	"path/filepath"
	"slices"
	"strings"

	"github.com/yosssi/gcss"
)

var gcssCompileCache = make(map[string]string)

const jobSpritesheetName = "jobs.gcss"

func compileGCSS(reader io.Reader) (string, error) {
	compileBuf := bytes.Buffer{}
	if _, err := gcss.Compile(&compileBuf, reader); err != nil {
		return "", err
	}
	return compileBuf.String(), nil
}

func compileJobSpritesheetGCSS() error {
	jobs, err := getFormChoices("jobs")
	if err != nil {
		return err
	}
	slices.Sort(jobs)
	var gcss strings.Builder
	gcss.WriteString(".input-checkbox-choice.from-jobs, .input-radio-choice.from-jobs\n")
	for i, job := range jobs {
		gcss.WriteString(fmt.Sprintf("  input[value=%s] + label\n    background-position-x: %dpx\n", job, -(i * 76)))
	}
	gcssCompileCache[jobSpritesheetName], err = compileGCSS(strings.NewReader(gcss.String()))
	return err
}

func httpServeCompiledGCSS(w http.ResponseWriter, name string) {
	w.Header().Add("Content-Type", "text/css")
	w.Header().Set("Cache-Control", "public, max-age=3600")
	w.WriteHeader(200)
	io.WriteString(w, gcssCompileCache[name])
}

func httpBaseHandleGCSS(w http.ResponseWriter, r *http.Request, path []string) bool {
	// check path
	file := path[len(path)-1]
	fileExt := filepath.Ext(file)
	if fileExt != ".css" && fileExt != ".gcss" {
		return false
	}
	file = strings.TrimSuffix(file, fileExt) + ".gcss"

	// serve already compiled gcss > css
	if gcssCompileCache[file] != "" {
		httpServeCompiledGCSS(w, file)
		return true
	}

	log.Printf(" >> compile %s", file)

	// job sprite sheet
	if file == jobSpritesheetName {
		if err := compileJobSpritesheetGCSS(); err != nil {
			log.Println(" >> GCSS Error: ", err)
			httpHandleErrorText(w, err)
			return true
		}
		httpServeCompiledGCSS(w, file)
		return true
	}

	// read gcss file
	gcssReader, err := staticFS.Open(filepath.Join(staticEmbedPath, file))
	if err != nil {
		httpHandleErrorText(w, err)
		return true
	}
	defer gcssReader.Close()
	gcssCompileCache[file], err = compileGCSS(gcssReader)
	if err != nil {
		log.Println(" >> GCSS Error: ", err)
		httpHandleErrorText(w, err)
		return true
	}
	httpServeCompiledGCSS(w, file)
	return true
}