package api

import (
	"encoding/json"
	"net/http"
	"strconv"
	"time"

	"github.com/containarr/server/internal/broker"
	grpcgateway "github.com/containarr/server/internal/grpc"
	agentv1 "github.com/containarr/server/internal/proto/agentv1"
	"github.com/containarr/server/internal/store"
	"github.com/go-chi/chi/v5"
	"github.com/google/uuid"
	"github.com/gorilla/websocket"
)

var upgrader = websocket.Upgrader{
	CheckOrigin: func(r *http.Request) bool { return true },
}

type Handler struct {
	store    *store.Store
	registry *grpcgateway.Registry
	broker   *broker.Broker
}

func NewHandler(s *store.Store, r *grpcgateway.Registry, b *broker.Broker) *Handler {
	return &Handler{store: s, registry: r, broker: b}
}

type agentDTO struct {
	ID         string    `json:"id"`
	Hostname   string    `json:"hostname"`
	Alias      string    `json:"alias"`
	IPAddress  string    `json:"ip_address"`
	Arch       string    `json:"arch"`
	OS         string    `json:"os"`
	Online     bool      `json:"online"`
	LastSeenAt time.Time `json:"last_seen_at"`
}

// ── Agents ────────────────────────────────────────────────────────────────────

func (h *Handler) ListAgents(w http.ResponseWriter, r *http.Request) {
	persisted, err := h.store.ListAgents()
	if err != nil {
		http.Error(w, "store error", http.StatusInternalServerError)
		return
	}
	liveByID := map[string]*grpcgateway.AgentState{}
	for _, s := range h.registry.List() {
		liveByID[s.ID] = s
	}
	out := make([]agentDTO, 0, len(persisted))
	for _, a := range persisted {
		dto := agentDTO{
			ID:        a.ID,
			Hostname:  a.Hostname,
			Alias:     a.Alias,
			IPAddress: a.IPAddress,
			Arch:      a.Arch,
			OS:        a.OS,
		}
		if live, ok := liveByID[a.ID]; ok {
			dto.Online = true
			dto.IPAddress = live.IPAddress
			dto.LastSeenAt = live.LastSeenAt
		}
		out = append(out, dto)
	}
	jsonOK(w, out)
}

func (h *Handler) UpdateAgent(w http.ResponseWriter, r *http.Request) {
	agentID := chi.URLParam(r, "agentID")
	var body struct {
		Alias string `json:"alias"`
	}
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		http.Error(w, "invalid body", http.StatusBadRequest)
		return
	}
	if err := h.store.UpdateAgentAlias(agentID, body.Alias); err != nil {
		http.Error(w, "store error", http.StatusInternalServerError)
		return
	}
	h.registry.UpdateAlias(agentID, body.Alias)

	a, err := h.store.GetAgent(agentID)
	if err != nil {
		http.Error(w, "not found", http.StatusNotFound)
		return
	}
	jsonOK(w, agentDTO{
		ID:        a.ID,
		Hostname:  a.Hostname,
		Alias:     a.Alias,
		IPAddress: a.IPAddress,
		Arch:      a.Arch,
		OS:        a.OS,
		Online:    a.Online,
	})
}

// ── Containers ────────────────────────────────────────────────────────────────

func (h *Handler) ListContainers(w http.ResponseWriter, r *http.Request) {
	type containerDTO struct {
		AgentID   string                 `json:"agent_id"`
		Hostname  string                 `json:"hostname"`
		Alias     string                 `json:"alias"`
		IPAddress string                 `json:"ip_address"`
		Container *agentv1.ContainerInfo `json:"container"`
	}
	var out []containerDTO
	for _, agent := range h.registry.List() {
		for _, c := range agent.Containers {
			out = append(out, containerDTO{
				AgentID:   agent.ID,
				Hostname:  agent.Hostname,
				Alias:     agent.Alias,
				IPAddress: agent.IPAddress,
				Container: c,
			})
		}
	}
	jsonOK(w, out)
}

func (h *Handler) ContainerAction(w http.ResponseWriter, r *http.Request) {
	agentID := chi.URLParam(r, "agentID")
	containerID := chi.URLParam(r, "containerID")

	var body struct {
		Action string `json:"action"`
	}
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		http.Error(w, "invalid body", http.StatusBadRequest)
		return
	}

	action, ok := map[string]agentv1.ContainerAction{
		"start":   agentv1.ContainerAction_CONTAINER_ACTION_START,
		"stop":    agentv1.ContainerAction_CONTAINER_ACTION_STOP,
		"restart": agentv1.ContainerAction_CONTAINER_ACTION_RESTART,
		"remove":  agentv1.ContainerAction_CONTAINER_ACTION_REMOVE,
	}[body.Action]
	if !ok {
		http.Error(w, "unknown action", http.StatusBadRequest)
		return
	}

	cmdID := uuid.NewString()
	sent := h.registry.Send(agentID, &agentv1.ServerMessage{
		Payload: &agentv1.ServerMessage_ContainerCmd{
			ContainerCmd: &agentv1.ContainerCommand{
				CommandId:   cmdID,
				ContainerId: containerID,
				Action:      action,
			},
		},
	})
	if !sent {
		http.Error(w, "agent not connected", http.StatusServiceUnavailable)
		return
	}
	jsonOK(w, map[string]string{"command_id": cmdID})
}

// ── Agent token provisioning ──────────────────────────────────────────────────

func (h *Handler) CreateAgentToken(w http.ResponseWriter, r *http.Request) {
	var body struct {
		Hostname string `json:"hostname"`
	}
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil || body.Hostname == "" {
		http.Error(w, "hostname required", http.StatusBadRequest)
		return
	}
	id := uuid.NewString()
	token := uuid.NewString()
	if err := h.store.CreateAgentToken(id, token, body.Hostname); err != nil {
		http.Error(w, "store error", http.StatusInternalServerError)
		return
	}
	jsonOK(w, map[string]string{"agent_id": id, "token": token})
}

// ── Container log stream ──────────────────────────────────────────────────────

func (h *Handler) LogsWS(w http.ResponseWriter, r *http.Request) {
	agentID := chi.URLParam(r, "agentID")
	containerID := chi.URLParam(r, "containerID")

	follow := r.URL.Query().Get("follow") != "false"
	tail := int32(100)
	if t := r.URL.Query().Get("tail"); t != "" {
		if n, err := strconv.Atoi(t); err == nil && n > 0 {
			tail = int32(n)
		}
	}

	conn, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		return
	}
	defer conn.Close()

	sent := h.registry.Send(agentID, &agentv1.ServerMessage{
		Payload: &agentv1.ServerMessage_StreamLogs{
			StreamLogs: &agentv1.StreamLogsCommand{
				CommandId:   uuid.NewString(),
				ContainerId: containerID,
				Follow:      follow,
				Tail:        tail,
			},
		},
	})
	if !sent {
		conn.WriteMessage(websocket.TextMessage, []byte(`{"error":"agent not connected"}`))
		return
	}

	sub := h.broker.Subscribe()
	defer h.broker.Unsubscribe(sub)

	done := make(chan struct{})
	go func() {
		defer close(done)
		for {
			if _, _, err := conn.ReadMessage(); err != nil {
				return
			}
		}
	}()

	for {
		select {
		case <-done:
			return
		case raw, ok := <-sub:
			if !ok {
				return
			}
			var envelope struct {
				Type    string          `json:"type"`
				AgentID string          `json:"agent_id"`
				Payload json.RawMessage `json:"payload"`
			}
			if json.Unmarshal(raw, &envelope) != nil {
				continue
			}
			if envelope.Type != "log.chunk" || envelope.AgentID != agentID {
				continue
			}
			var chunk struct {
				ContainerID string `json:"container_id"`
				Stream      string `json:"stream"`
				Data        []byte `json:"data"`
			}
			if json.Unmarshal(envelope.Payload, &chunk) != nil {
				continue
			}
			if chunk.ContainerID != containerID {
				continue
			}
			msg, _ := json.Marshal(map[string]string{
				"stream": chunk.Stream,
				"line":   string(chunk.Data),
			})
			if err := conn.WriteMessage(websocket.TextMessage, msg); err != nil {
				return
			}
		}
	}
}

// ── WebSocket event stream ────────────────────────────────────────────────────

func (h *Handler) EventsWS(w http.ResponseWriter, r *http.Request) {
	conn, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		return
	}
	defer conn.Close()

	sub := h.broker.Subscribe()
	defer h.broker.Unsubscribe(sub)

	for data := range sub {
		if err := conn.WriteMessage(websocket.TextMessage, data); err != nil {
			return
		}
	}
}

func jsonOK(w http.ResponseWriter, v any) {
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(v)
}