package main

import (
	"log"
	"net/http"

	"github.com/pocketbase/pocketbase"
	"github.com/pocketbase/pocketbase/core"
)

func main() {
	app := pocketbase.New()

	app.OnRecordViewRequest().BindFunc(addLastModified)

	app.OnRecordUpdateRequest().BindFunc(ifUnmodifiedSince)

	app.OnRecordDeleteRequest().BindFunc(ifUnmodifiedSince)

	if err := app.Start(); err != nil {
		log.Fatal(err)
	}
}

func addLastModified(e *core.RecordRequestEvent) error {
	updated := e.Record.GetString("updated")

	if updated != "" {
		e.Response.Header().Add("Last-Modified", updated)
	}

	return e.Next()
}

func ifUnmodifiedSince(e *core.RecordRequestEvent) error {
	updated := e.Record.GetString("updated")

	if updated != "" {
		header := e.Request.Header.Get("If-Unmodified-Since")

		if header == "" || header != updated {
			e.Response.Header().Add("Last-Modified", updated)

			if header == "" {
				return e.Error(http.StatusPreconditionRequired, "Header If-Unmodified-Since is required", nil)
			} else if header != updated {
				return e.Error(http.StatusPreconditionFailed, "Record was modified after retrieval", nil)
			}
		}
	}

	return e.Next()
}