package api

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"time"

	"git.joco.dk/sng/fermentord/internal/controllers"
	"git.joco.dk/sng/fermentord/internal/dal"
	"github.com/getsentry/sentry-go"
	"github.com/rs/zerolog/log"
)

type API struct {
	db                   *dal.DAL
	config               *controllers.Config
	configChangeCallback func()
}

func NewAPI(db *dal.DAL) *API {
	return &API{
		db: db,
	}
}

func (a *API) HealthCheck(w http.ResponseWriter, r *http.Request) {
	defer sentry.Recover()

	tx, err := a.db.Begin()
	if err != nil {
		http.Error(w, "Unhealthy", http.StatusServiceUnavailable)
		return
	}

	var version string
	err = tx.QueryRow("SELECT version()").Scan(&version)
	if err != nil {
		http.Error(w, "Unhealthy", http.StatusServiceUnavailable)
		return
	}

	w.Write([]byte("Healthy"))
}

func (a *API) GetConfig(w http.ResponseWriter, r *http.Request) {
	defer sentry.Recover()

	resp, err := json.MarshalIndent(a.config, "", "  ")
	if err != nil {
		log.Panic().Err(err).Msg("Error marshalling configuration.")
	}

	w.Write(resp)
}

func (a *API) GetTemperatures(w http.ResponseWriter, r *http.Request) {
	defer sentry.Recover()

	ctx := context.Background()
	tx, err := a.db.Begin()
	defer tx.Rollback()
	if err != nil {
		log.Panic().Err(err).Msg("Failed to start DB transaction.")
	}

	keys, ok := r.URL.Query()["since"]
	if !ok || len(keys[0]) < 1 {
		http.Error(w, "Missing since parameter.", http.StatusBadRequest)
		return
	}

	since, err := time.Parse(time.RFC3339, keys[0])
	if err != nil {
		http.Error(w, "Invalid format of since parameter. Expected RFC3339 formatted string.", http.StatusBadRequest)
		return
	}

	dbCtx, cancel := context.WithTimeout(ctx, 30*time.Second)
	defer cancel()
	readings, err := dal.LoadTemperatureReadingsSince(dbCtx, tx, since)
	if err != nil {
		log.Panic().Err(err).Msg("Failed to load temperature readings from DB.")
	}
	tx.Commit()

	data, err := json.MarshalIndent(readings, "", "  ")
	if err != nil {
		log.Panic().Err(err).Msg("Failed to serialize temperature readings to JSON.")
	}

	fmt.Fprintf(w, string(data))
}

func (a *API) GetStateChanges(w http.ResponseWriter, r *http.Request) {
	defer sentry.Recover()

	ctx := context.Background()
	tx, err := a.db.Begin()
	if err != nil {
		log.Panic().Err(err).Msg("Failed to start DB transaction.")
	}

	keys, ok := r.URL.Query()["since"]
	if !ok || len(keys[0]) < 1 {
		http.Error(w, "Missing since parameter.", http.StatusBadRequest)
		return
	}

	since, err := time.Parse(time.RFC3339, keys[0])
	if err != nil {
		http.Error(w, "Invalid format of since parameter. Expected RFC3339 formatted string.", http.StatusBadRequest)
		return
	}

	dbCtx, cancel := context.WithTimeout(ctx, 30*time.Second)
	defer cancel()
	readings, err := dal.LoadChamberStateChangesSince(dbCtx, tx, since)
	if err != nil {
		log.Panic().Err(err).Msg("Failed to load temperature readings from DB.")
	}
	tx.Commit()

	data, err := json.MarshalIndent(readings, "", "  ")
	if err != nil {
		log.Panic().Err(err).Msg("Failed to serialize temperature readings to JSON.")
	}

	fmt.Fprintf(w, string(data))
}