package api

import (
	"context"
	"errors"
	"fmt"
	"log/slog"
	"net/http"

	"github.com/go-chi/chi/v5"

	"github.com/alexei/tinyforge/internal/store"
)

// listInstances handles GET /api/projects/{id}/stages/{stage}/instances.
// Reads the normalized container index — the legacy `instances` table is gone.
// JSON shape stays Container-shaped (id, container_id, image_tag, subdomain,
// state, port, etc.), so the frontend type may show some renamed fields
// (status→state, last_alive_at→last_seen_at).
func (s *Server) listInstances(w http.ResponseWriter, r *http.Request) {
	stageID := chi.URLParam(r, "stage")

	if _, err := s.store.GetStageByID(stageID); err != nil {
		if errors.Is(err, store.ErrNotFound) {
			respondNotFound(w, "stage")
			return
		}
		slog.Error("failed to get stage", "error", err)
		respondError(w, http.StatusInternalServerError, "internal server error")
		return
	}

	containers, err := s.store.ListContainersByStageID(stageID)
	if err != nil {
		slog.Error("failed to list containers", "error", err)
		respondError(w, http.StatusInternalServerError, "internal server error")
		return
	}

	// Reconcile container state with Docker's actual state — covers the
	// case where a container was killed externally between deployer writes
	// and the next reconciler tick.
	ctx := r.Context()
	for i, c := range containers {
		if c.ContainerID == "" || c.State == "removing" {
			continue
		}
		running, err := s.docker.IsContainerRunning(ctx, c.ContainerID)
		if err != nil {
			continue
		}
		actual := "stopped"
		if running {
			actual = "running"
		}
		if c.State != actual {
			containers[i].State = actual
			_ = s.store.UpdateContainerState(c.ID, actual)
		}
	}

	respondJSON(w, http.StatusOK, containers)
}

// deployRequest is the expected JSON body for triggering a deploy.
type deployRequest struct {
	ImageTag string `json:"image_tag"`
}

// deployInstance handles POST /api/projects/{id}/stages/{stage}/instances.
func (s *Server) deployInstance(w http.ResponseWriter, r *http.Request) {
	projectID := chi.URLParam(r, "id")
	stageID := chi.URLParam(r, "stage")

	if _, err := s.store.GetProjectByID(projectID); err != nil {
		if errors.Is(err, store.ErrNotFound) {
			respondNotFound(w, "project")
			return
		}
		slog.Error("failed to get project", "error", err)
		respondError(w, http.StatusInternalServerError, "internal server error")
		return
	}

	if _, err := s.store.GetStageByID(stageID); err != nil {
		if errors.Is(err, store.ErrNotFound) {
			respondNotFound(w, "stage")
			return
		}
		slog.Error("failed to get stage", "error", err)
		respondError(w, http.StatusInternalServerError, "internal server error")
		return
	}

	var req deployRequest
	if !decodeJSON(w, r, &req) {
		return
	}

	if req.ImageTag == "" {
		respondError(w, http.StatusBadRequest, "image_tag is required")
		return
	}

	deployID, err := s.deployer.AsyncTriggerDeploy(r.Context(), projectID, stageID, req.ImageTag)
	if err != nil {
		slog.Error("failed to trigger deploy", "error", err)
		respondError(w, http.StatusInternalServerError, "internal server error")
		return
	}
	respondJSON(w, http.StatusAccepted, map[string]string{
		"status":     "deploying",
		"deploy_id":  deployID,
		"project_id": projectID,
		"stage_id":   stageID,
		"image_tag":  req.ImageTag,
	})
}

// removeInstance handles DELETE /api/projects/{id}/stages/{stage}/instances/{iid}.
// {iid} is the container row ID (same UUID as the legacy instance ID).
func (s *Server) removeInstance(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "iid")

	c, err := s.store.GetContainerByID(id)
	if err != nil {
		if errors.Is(err, store.ErrNotFound) {
			respondNotFound(w, "container")
			return
		}
		slog.Error("failed to get container", "error", err)
		respondError(w, http.StatusInternalServerError, "internal server error")
		return
	}

	// Remove the Docker container if it has one.
	if c.ContainerID != "" {
		if err := s.docker.RemoveContainer(r.Context(), c.ContainerID, true); err != nil {
			slog.Error("remove container", "container_id", c.ContainerID, "error", err)
		}
	}

	// Delete proxy route if it has one.
	if c.ProxyRouteID != "" {
		if err := s.proxyProvider.DeleteRoute(r.Context(), c.ProxyRouteID); err != nil {
			slog.Warn("delete proxy route on container removal", "route_id", c.ProxyRouteID, "error", err)
		}
	}

	// Delete container row.
	if err := s.store.DeleteContainer(id); err != nil {
		respondError(w, http.StatusInternalServerError, "failed to delete container")
		return
	}
	respondJSON(w, http.StatusOK, map[string]string{"deleted": id})
}

// stopInstance handles POST /api/projects/{id}/stages/{stage}/instances/{iid}/stop.
func (s *Server) stopInstance(w http.ResponseWriter, r *http.Request) {
	s.controlInstance(w, r, "stop")
}

// startInstance handles POST /api/projects/{id}/stages/{stage}/instances/{iid}/start.
func (s *Server) startInstance(w http.ResponseWriter, r *http.Request) {
	s.controlInstance(w, r, "start")
}

// restartInstance handles POST /api/projects/{id}/stages/{stage}/instances/{iid}/restart.
func (s *Server) restartInstance(w http.ResponseWriter, r *http.Request) {
	s.controlInstance(w, r, "restart")
}

// controlInstance performs a stop/start/restart action on a container.
func (s *Server) controlInstance(w http.ResponseWriter, r *http.Request, action string) {
	id := chi.URLParam(r, "iid")

	c, err := s.store.GetContainerByID(id)
	if err != nil {
		if errors.Is(err, store.ErrNotFound) {
			respondNotFound(w, "container")
			return
		}
		slog.Error("failed to get container", "error", err)
		respondError(w, http.StatusInternalServerError, "internal server error")
		return
	}

	if c.ContainerID == "" {
		respondError(w, http.StatusBadRequest, "container row has no docker container bound")
		return
	}

	ctx := r.Context()
	var controlErr error
	var newState string

	switch action {
	case "stop":
		controlErr = s.docker.StopContainer(ctx, c.ContainerID, 10)
		newState = "stopped"
	case "start":
		controlErr = s.docker.StartContainer(ctx, c.ContainerID)
		newState = "running"
	case "restart":
		controlErr = s.docker.RestartContainer(ctx, c.ContainerID, 10)
		newState = "running"
	default:
		respondError(w, http.StatusBadRequest, fmt.Sprintf("unknown action: %s", action))
		return
	}

	if controlErr != nil {
		slog.Error("failed to control container", "action", action, "id", id, "error", controlErr)
		respondError(w, http.StatusInternalServerError, "internal server error")
		return
	}

	if err := s.store.UpdateContainerState(id, newState); err != nil {
		slog.Error("update container state", "id", id, "state", newState, "error", err)
	}

	respondJSON(w, http.StatusOK, map[string]string{
		"instance_id": id,
		"action":      action,
		"status":      newState,
	})
}

// DeployTriggerer is the interface for triggering deployments.
type DeployTriggerer interface {
	TriggerDeploy(ctx context.Context, projectID, stageID, imageTag string) error
	AsyncTriggerDeploy(ctx context.Context, projectID, stageID, imageTag string) (string, error)
}