package tplmap

import (
	"fmt"
	"log"
	"os"
	"prose/common"
	"prose/watcher"
	"strconv"
	"sync"
	"time"

	"github.com/aymerick/raymond"
)

type tplMap struct {
	mu        sync.RWMutex
	templates map[string]*raymond.Template
}

func New() (watcher.AutoMap[string, *raymond.Template], error) {
	folder, err := os.ReadDir("templates/")
	if err != nil {
		return nil, fmt.Errorf("could not load templates directory: %w", err)
	}

	tm := &tplMap{
		templates: make(map[string]*raymond.Template),
	}

	for _, s := range folder {
		err := tm.fetchLocked(s.Name())
		if err != nil {
			return nil, fmt.Errorf("could not load template %q: %w", s.Name(), err)
		}
		log.Printf("loaded template %q", s.Name())
	}

	go watcher.Watch("templates/", tm)

	return tm, nil
}

func (tm *tplMap) Get(filename string) (*raymond.Template, bool) {
	tm.mu.RLock()
	defer tm.mu.RUnlock()
	got, ok := tm.templates[filename]
	return got, ok
}

func (tm *tplMap) Delete(filename string) error {
	tm.mu.Lock()
	defer tm.mu.Unlock()
	delete(tm.templates, filename)
	return nil
}

func (tm *tplMap) Fetch(filename string) error {
	tm.mu.Lock()
	defer tm.mu.Unlock()
	return tm.fetchLocked(filename)
}

func (tm *tplMap) fetchLocked(filename string) error {
	tpl, err := raymond.ParseFile("templates/" + filename)
	if err != nil {
		return fmt.Errorf("could not parse template %q: %w", filename, err)
	}
	tpl.RegisterHelper("datetime", func(timeStr string) string {
		timestamp, err := strconv.ParseInt(timeStr, 10, 64)
		if err != nil {
			log.Printf("Could not parse timestamp '%v', falling back to current time", timeStr)
			timestamp = time.Now().Unix()
		}
		return time.Unix(timestamp, 0).Format("Jan 2 2006, 3:04 PM")
	})
	tpl.RegisterHelper("rssDatetime", func(timeStr string) string {
		timestamp, err := strconv.ParseInt(timeStr, 10, 64)
		if err != nil {
			log.Printf("Could not parse timestamp '%v', falling back to current time", timeStr)
			timestamp = time.Now().Unix()
		}
		return common.RSSDatetime(timestamp)
	})
	tpl.RegisterHelper("getFullUrl", func(slug string) string {
		return common.BlogURL + "/" + slug
	})
	tm.templates[filename] = tpl
	return nil
}