package containers

import (
	"context"
	"errors"
	"fmt"
	"log/slog"
	"time"

	"github.com/docker/docker/client"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

const containerAPICallingThreshold = 100 * time.Millisecond

func NewContainerProbe(logger *slog.Logger, containerID string, probe Probe, inspector Inspector) *ContainerProber {
	return &ContainerProber{
		containerID: containerID,
		probe:       probe,
		inspector:   inspector,
		logger:      logger,
	}
}

type ContainerProber struct {
	probe       Probe
	inspector   Inspector
	logger      *slog.Logger
	containerID string
}

func (p *ContainerProber) WaitReady(ctx context.Context) error {
	waitCtx, cancel := context.WithCancel(ctx)

	monitorErr := p.inspectMonitor(ctx)
	probeReady, probeErr := p.probe.Execute(waitCtx)

	defer cancel()

	for {
		select {
		case <-ctx.Done():
			return ctx.Err()
		case err := <-monitorErr:
			if err != nil {
				return err
			}
		case ready := <-probeReady:
			if ready {
				return nil
			}
		case err := <-probeErr:
			if respStatus, ok := status.FromError(err); ok {
				if respStatus.Code() == codes.Unavailable {
					continue
				}
			}
			if err != nil {
				p.logger.Error("Error occurred while probing container", slog.String("err", err.Error()))
			}
		}
	}
}

func (p *ContainerProber) inspectMonitor(ctx context.Context) (errs chan error) {
	errs = make(chan error)
	go func() {
		defer close(errs)
		for ctx.Err() == nil {
			containerInfo, err := p.inspector.ContainerInspect(ctx, p.containerID)
			if err != nil {
				if client.IsErrNotFound(err) {
					errs <- fmt.Errorf("container %s does not exist", p.containerID)
					return
				} else if errors.Is(err, context.Canceled) {
					return
				}
				p.logger.Error("Error occurred while inspecting container", slog.String("err", err.Error()))
			}

			if !containerInfo.State.Running {
				errs <- fmt.Errorf("container %s is not running", p.containerID)
				return
			}

			// sleep for a bit to not overload container API
			time.Sleep(containerAPICallingThreshold)
		}
	}()

	return errs
}