package alertmanager

import (
	"context"
	"io"
	"net/http"
	"strconv"
	"time"

	"github.com/gorilla/mux"
	"go.signoz.io/signoz/pkg/errors"
	"go.signoz.io/signoz/pkg/http/render"
	"go.signoz.io/signoz/pkg/types/alertmanagertypes"
	"go.signoz.io/signoz/pkg/types/authtypes"
)

type API struct {
	alertmanager Alertmanager
}

func NewAPI(alertmanager Alertmanager) *API {
	return &API{
		alertmanager: alertmanager,
	}
}

func (api *API) GetAlerts(rw http.ResponseWriter, req *http.Request) {
	ctx, cancel := context.WithTimeout(req.Context(), 30*time.Second)
	defer cancel()

	claims, ok := authtypes.ClaimsFromContext(ctx)
	if !ok {
		render.Error(rw, errors.Newf(errors.TypeUnauthenticated, errors.CodeUnauthenticated, "unauthenticated"))
		return
	}

	params, err := alertmanagertypes.NewGettableAlertsParams(req)
	if err != nil {
		render.Error(rw, err)
		return
	}

	alerts, err := api.alertmanager.GetAlerts(ctx, claims.OrgID, params)
	if err != nil {
		render.Error(rw, err)
		return
	}

	render.Success(rw, http.StatusOK, alerts)
}

func (api *API) TestReceiver(rw http.ResponseWriter, req *http.Request) {
	ctx, cancel := context.WithTimeout(req.Context(), 30*time.Second)
	defer cancel()

	claims, ok := authtypes.ClaimsFromContext(ctx)
	if !ok {
		render.Error(rw, errors.Newf(errors.TypeUnauthenticated, errors.CodeUnauthenticated, "unauthenticated"))
		return
	}

	body, err := io.ReadAll(req.Body)
	if err != nil {
		render.Error(rw, err)
		return
	}
	defer req.Body.Close() //nolint:errcheck

	receiver, err := alertmanagertypes.NewReceiver(string(body))
	if err != nil {
		render.Error(rw, err)
		return
	}

	err = api.alertmanager.TestReceiver(ctx, claims.OrgID, receiver)
	if err != nil {
		render.Error(rw, err)
		return
	}

	render.Success(rw, http.StatusNoContent, nil)
}

func (api *API) ListChannels(rw http.ResponseWriter, req *http.Request) {
	ctx, cancel := context.WithTimeout(req.Context(), 30*time.Second)
	defer cancel()

	claims, ok := authtypes.ClaimsFromContext(ctx)
	if !ok {
		render.Error(rw, errors.Newf(errors.TypeUnauthenticated, errors.CodeUnauthenticated, "unauthenticated"))
		return
	}

	channels, err := api.alertmanager.ListChannels(ctx, claims.OrgID)
	if err != nil {
		render.Error(rw, err)
		return
	}

	// This ensures that the UI receives an empty array instead of null
	if len(channels) == 0 {
		channels = make([]*alertmanagertypes.Channel, 0)
	}

	render.Success(rw, http.StatusOK, channels)
}

func (api *API) ListAllChannels(rw http.ResponseWriter, req *http.Request) {
	ctx, cancel := context.WithTimeout(req.Context(), 30*time.Second)
	defer cancel()

	channels, err := api.alertmanager.ListAllChannels(ctx)
	if err != nil {
		render.Error(rw, err)
		return
	}

	render.Success(rw, http.StatusOK, channels)
}

func (api *API) GetChannelByID(rw http.ResponseWriter, req *http.Request) {
	ctx, cancel := context.WithTimeout(req.Context(), 30*time.Second)
	defer cancel()

	claims, ok := authtypes.ClaimsFromContext(ctx)
	if !ok {
		render.Error(rw, errors.Newf(errors.TypeUnauthenticated, errors.CodeUnauthenticated, "unauthenticated"))
		return
	}

	vars := mux.Vars(req)
	if vars == nil {
		render.Error(rw, errors.Newf(errors.TypeInvalidInput, errors.CodeInvalidInput, "id is required in path"))
		return
	}

	idString, ok := vars["id"]
	if !ok {
		render.Error(rw, errors.Newf(errors.TypeInvalidInput, errors.CodeInvalidInput, "id is required in path"))
		return
	}

	id, err := strconv.Atoi(idString)
	if err != nil {
		render.Error(rw, errors.Newf(errors.TypeInvalidInput, errors.CodeInvalidInput, "id is not a valid integer"))
		return
	}

	channel, err := api.alertmanager.GetChannelByID(ctx, claims.OrgID, id)
	if err != nil {
		render.Error(rw, err)
		return
	}

	render.Success(rw, http.StatusOK, channel)
}

func (api *API) UpdateChannelByID(rw http.ResponseWriter, req *http.Request) {
	ctx, cancel := context.WithTimeout(req.Context(), 30*time.Second)
	defer cancel()

	claims, ok := authtypes.ClaimsFromContext(ctx)
	if !ok {
		render.Error(rw, errors.Newf(errors.TypeUnauthenticated, errors.CodeUnauthenticated, "unauthenticated"))
		return
	}

	vars := mux.Vars(req)
	if vars == nil {
		render.Error(rw, errors.Newf(errors.TypeInvalidInput, errors.CodeInvalidInput, "id is required in path"))
		return
	}

	idString, ok := vars["id"]
	if !ok {
		render.Error(rw, errors.Newf(errors.TypeInvalidInput, errors.CodeInvalidInput, "id is required in path"))
		return
	}

	id, err := strconv.Atoi(idString)
	if err != nil {
		render.Error(rw, errors.Newf(errors.TypeInvalidInput, errors.CodeInvalidInput, "id is not a valid integer"))
		return
	}

	body, err := io.ReadAll(req.Body)
	if err != nil {
		render.Error(rw, err)
		return
	}
	defer req.Body.Close() //nolint:errcheck

	receiver, err := alertmanagertypes.NewReceiver(string(body))
	if err != nil {
		render.Error(rw, err)
		return
	}

	err = api.alertmanager.UpdateChannelByReceiverAndID(ctx, claims.OrgID, receiver, id)
	if err != nil {
		render.Error(rw, err)
		return
	}

	render.Success(rw, http.StatusNoContent, nil)
}

func (api *API) DeleteChannelByID(rw http.ResponseWriter, req *http.Request) {
	ctx, cancel := context.WithTimeout(req.Context(), 30*time.Second)
	defer cancel()

	claims, ok := authtypes.ClaimsFromContext(ctx)
	if !ok {
		render.Error(rw, errors.Newf(errors.TypeUnauthenticated, errors.CodeUnauthenticated, "unauthenticated"))
		return
	}

	vars := mux.Vars(req)
	if vars == nil {
		render.Error(rw, errors.Newf(errors.TypeInvalidInput, errors.CodeInvalidInput, "id is required in path"))
		return
	}

	idString, ok := vars["id"]
	if !ok {
		render.Error(rw, errors.Newf(errors.TypeInvalidInput, errors.CodeInvalidInput, "id is required in path"))
		return
	}

	id, err := strconv.Atoi(idString)
	if err != nil {
		render.Error(rw, errors.Newf(errors.TypeInvalidInput, errors.CodeInvalidInput, "id is not a valid integer"))
		return
	}

	err = api.alertmanager.DeleteChannelByID(ctx, claims.OrgID, id)
	if err != nil {
		render.Error(rw, err)
		return
	}

	render.Success(rw, http.StatusNoContent, nil)
}

func (api *API) CreateChannel(rw http.ResponseWriter, req *http.Request) {
	ctx, cancel := context.WithTimeout(req.Context(), 30*time.Second)
	defer cancel()

	claims, ok := authtypes.ClaimsFromContext(ctx)
	if !ok {
		render.Error(rw, errors.Newf(errors.TypeUnauthenticated, errors.CodeUnauthenticated, "unauthenticated"))
		return
	}

	body, err := io.ReadAll(req.Body)
	if err != nil {
		render.Error(rw, err)
		return
	}
	defer req.Body.Close() //nolint:errcheck

	receiver, err := alertmanagertypes.NewReceiver(string(body))
	if err != nil {
		render.Error(rw, err)
		return
	}

	err = api.alertmanager.CreateChannel(ctx, claims.OrgID, receiver)
	if err != nil {
		render.Error(rw, err)
		return
	}

	render.Success(rw, http.StatusNoContent, nil)
}