package api

import (
	"bufio"
	"encoding/json"
	"fmt"
	"io"
	"log/slog"
	"net/http"
	"strconv"

	"git.clustercockpit.org/moebiusband/go-http-skeleton/internal/repository"
)

type ErrorResponse struct {
	// Statustext of Errorcode
	Status string `json:"status"`
	Error  string `json:"error"` // Error Message
}

func MountApiEndpoints(r *http.ServeMux) {
	r.HandleFunc("POST /api/news/", createNewsItem)
	r.HandleFunc("GET /api/news/", readNewsItems)
	r.HandleFunc("GET /api/news/{id}", readNewsItem)
	r.HandleFunc("PATCH /api/news/", updateNewsItem)
	r.HandleFunc("DELETE /api/news/{id}", deleteNewsItem)
}

func handleError(err error, statusCode int, rw http.ResponseWriter) {
	slog.Warn("rest error", "error", err)
	rw.Header().Add("Content-Type", "application/json")
	rw.WriteHeader(statusCode)
	json.NewEncoder(rw).Encode(ErrorResponse{
		Status: http.StatusText(statusCode),
		Error:  err.Error(),
	})
}

func decode(r io.Reader, val any) error {
	dec := json.NewDecoder(r)
	dec.DisallowUnknownFields()
	return dec.Decode(val)
}

func createNewsItem(rw http.ResponseWriter, r *http.Request) {
	req := repository.CreateNewsEntryParams{}
	if err := decode(r.Body, &req); err != nil {
		handleError(fmt.Errorf("parsing request body failed: %w", err), http.StatusBadRequest, rw)
		return
	}

	repo := repository.GetRepository()
	err := repo.CreateNewsEntry(r.Context(), req)
	if err != nil {
		handleError(err, http.StatusBadRequest, rw)
		return
	}
}

func readNewsItems(rw http.ResponseWriter, r *http.Request) {
	repo := repository.GetRepository()
	items, err := repo.ListNews(r.Context())
	if err != nil {
		handleError(err, http.StatusBadRequest, rw)
		return
	}

	slog.Debug("/api/news returned", "newscount", len(items))
	rw.Header().Add("Content-Type", "application/json")
	bw := bufio.NewWriter(rw)
	defer bw.Flush()

	if err := json.NewEncoder(bw).Encode(items); err != nil {
		handleError(err, http.StatusInternalServerError, rw)
		return
	}
}

func readNewsItem(rw http.ResponseWriter, r *http.Request) {
	repo := repository.GetRepository()
	id, err := strconv.ParseInt(r.PathValue("id"), 10, 64)
	if err != nil {
		handleError(err, http.StatusBadRequest, rw)
		return
	}

	item, err := repo.GetNewsEntry(r.Context(), id)
	if err != nil {
		handleError(err, http.StatusBadRequest, rw)
		return
	}

	rw.Header().Add("Content-Type", "application/json")
	bw := bufio.NewWriter(rw)
	defer bw.Flush()

	if err := json.NewEncoder(bw).Encode(item); err != nil {
		handleError(err, http.StatusInternalServerError, rw)
		return
	}
}

func updateNewsItem(rw http.ResponseWriter, r *http.Request) {
	req := repository.UpdateNewsEntryParams{}
	if err := decode(r.Body, &req); err != nil {
		handleError(fmt.Errorf("parsing request body failed: %w", err), http.StatusBadRequest, rw)
		return
	}

	repo := repository.GetRepository()
	err := repo.UpdateNewsEntry(r.Context(), req)
	if err != nil {
		handleError(err, http.StatusBadRequest, rw)
		return
	}
}

func deleteNewsItem(rw http.ResponseWriter, r *http.Request) {
	repo := repository.GetRepository()
	id, err := strconv.ParseInt(r.PathValue("id"), 10, 64)
	if err != nil {
		handleError(err, http.StatusBadRequest, rw)
		return
	}

	err = repo.DeleteNewsEntry(r.Context(), id)
	if err != nil {
		handleError(err, http.StatusBadRequest, rw)
		return
	}
}