package client

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

type Client struct {
	baseURL    string
	httpClient *http.Client
}

type EnrollRequest struct {
	ClusterID            string         `json:"cluster_id"`
	JoinToken            string         `json:"join_token"`
	NodeName             string         `json:"node_name"`
	NodeFingerprint      string         `json:"node_fingerprint"`
	PublicKey            string         `json:"public_key"`
	ReportedCapabilities map[string]any `json:"reported_capabilities"`
	ReportedFacts        map[string]any `json:"reported_facts"`
	RequestedRoles       []string       `json:"requested_roles"`
}

type EnrollResponse struct {
	Status      string          `json:"status"`
	JoinRequest json.RawMessage `json:"join_request"`
}

type EnrollmentBootstrapRequest struct {
	ClusterID       string `json:"cluster_id"`
	NodeFingerprint string `json:"node_fingerprint"`
	PublicKey       string `json:"public_key"`
}

type EnrollmentBootstrapResponse struct {
	Status      string          `json:"status"`
	JoinRequest json.RawMessage `json:"join_request"`
	Bootstrap   *NodeBootstrap  `json:"node_bootstrap,omitempty"`
}

type NodeBootstrap struct {
	NodeID             string                      `json:"node_id"`
	ClusterID          string                      `json:"cluster_id"`
	IdentityStatus     string                      `json:"identity_status"`
	Certificate        map[string]any              `json:"certificate"`
	HeartbeatEndpoint  string                      `json:"heartbeat_endpoint"`
	ClusterAuthority   *ClusterAuthorityDescriptor `json:"cluster_authority,omitempty"`
	AuthorityPayload   json.RawMessage             `json:"authority_payload,omitempty"`
	AuthoritySignature *ClusterSignature           `json:"authority_signature,omitempty"`
}

type HeartbeatRequest struct {
	HealthStatus    string         `json:"health_status"`
	ReportedVersion string         `json:"reported_version,omitempty"`
	Capabilities    map[string]any `json:"capabilities"`
	ServiceStates   map[string]any `json:"service_states"`
	Metadata        map[string]any `json:"metadata"`
}

type HeartbeatResponse struct {
	Heartbeat    json.RawMessage       `json:"heartbeat"`
	TestingFlags EffectiveTestingFlags `json:"testing_flags"`
}

type EffectiveTestingFlags struct {
	Enabled               bool     `json:"enabled"`
	TelemetryEnabled      bool     `json:"telemetry_enabled"`
	SyntheticLinksEnabled bool     `json:"synthetic_links_enabled"`
	HistoryRetentionHours int      `json:"history_retention_hours"`
	AppliedScopes         []string `json:"applied_scopes"`
}

type DesiredWorkload struct {
	ServiceType  string         `json:"service_type"`
	DesiredState string         `json:"desired_state"`
	Version      string         `json:"version,omitempty"`
	RuntimeMode  string         `json:"runtime_mode"`
	ArtifactRef  string         `json:"artifact_ref,omitempty"`
	Config       map[string]any `json:"config"`
	Environment  map[string]any `json:"environment"`
}

type WorkloadStatusRequest struct {
	ReportedState string         `json:"reported_state"`
	RuntimeMode   string         `json:"runtime_mode"`
	Version       string         `json:"version,omitempty"`
	StatusPayload map[string]any `json:"status_payload"`
}

type MeshLinkObservationRequest struct {
	SourceNodeID string         `json:"source_node_id"`
	TargetNodeID string         `json:"target_node_id"`
	LinkStatus   string         `json:"link_status"`
	LatencyMs    *int           `json:"latency_ms,omitempty"`
	QualityScore *int           `json:"quality_score,omitempty"`
	Metadata     map[string]any `json:"metadata"`
}

type TelemetryRequest struct {
	CPUPercent       *float64       `json:"cpu_percent,omitempty"`
	MemoryUsedBytes  *int64         `json:"memory_used_bytes,omitempty"`
	MemoryTotalBytes *int64         `json:"memory_total_bytes,omitempty"`
	DiskUsedBytes    *int64         `json:"disk_used_bytes,omitempty"`
	DiskTotalBytes   *int64         `json:"disk_total_bytes,omitempty"`
	NetworkRxBytes   *int64         `json:"network_rx_bytes,omitempty"`
	NetworkTxBytes   *int64         `json:"network_tx_bytes,omitempty"`
	ProcessCount     *int           `json:"process_count,omitempty"`
	Payload          map[string]any `json:"payload"`
	ObservedAt       time.Time      `json:"observed_at"`
}

type SyntheticMeshRouteConfig struct {
	RouteID              string    `json:"route_id"`
	ClusterID            string    `json:"cluster_id"`
	SourceNodeID         string    `json:"source_node_id"`
	DestinationNodeID    string    `json:"destination_node_id"`
	Hops                 []string  `json:"hops"`
	AllowedChannels      []string  `json:"allowed_channels"`
	ExpiresAt            time.Time `json:"expires_at"`
	MaxTTL               int       `json:"max_ttl"`
	MaxHops              int       `json:"max_hops"`
	RouteVersion         string    `json:"route_version,omitempty"`
	PolicyVersion        string    `json:"policy_version,omitempty"`
	PeerDirectoryVersion string    `json:"peer_directory_version,omitempty"`
}

type SyntheticMeshConfig struct {
	Enabled                bool                               `json:"enabled"`
	SchemaVersion          string                             `json:"schema_version"`
	ClusterID              string                             `json:"cluster_id"`
	LocalNodeID            string                             `json:"local_node_id"`
	AuthorityRequired      bool                               `json:"authority_required"`
	ClusterAuthority       *ClusterAuthorityDescriptor        `json:"cluster_authority,omitempty"`
	AuthorityPayload       json.RawMessage                    `json:"authority_payload,omitempty"`
	AuthoritySignature     *ClusterSignature                  `json:"authority_signature,omitempty"`
	ConfigVersion          string                             `json:"config_version,omitempty"`
	PeerDirectoryVersion   string                             `json:"peer_directory_version,omitempty"`
	PolicyVersion          string                             `json:"policy_version,omitempty"`
	PeerEndpoints          map[string]string                  `json:"peer_endpoints"`
	PeerEndpointCandidates map[string][]PeerEndpointCandidate `json:"peer_endpoint_candidates,omitempty"`
	PeerDirectory          []PeerDirectoryEntry               `json:"peer_directory,omitempty"`
	RecoverySeeds          []PeerRecoverySeed                 `json:"recovery_seeds,omitempty"`
	RendezvousLeases       []PeerRendezvousLease              `json:"rendezvous_leases,omitempty"`
	RendezvousRelayPolicy  *RendezvousRelayPolicyReport       `json:"rendezvous_relay_policy,omitempty"`
	RoutePathDecisions     *RoutePathDecisionReport           `json:"route_path_decisions,omitempty"`
	Routes                 []SyntheticMeshRouteConfig         `json:"routes"`
	ProductionForwarding   bool                               `json:"production_forwarding"`
}

type ClusterAuthorityDescriptor struct {
	SchemaVersion        string    `json:"schema_version"`
	ClusterID            string    `json:"cluster_id"`
	AuthorityState       string    `json:"authority_state"`
	KeyAlgorithm         string    `json:"key_algorithm"`
	PublicKey            string    `json:"public_key"`
	PublicKeyFingerprint string    `json:"public_key_fingerprint"`
	CreatedAt            time.Time `json:"created_at"`
	UpdatedAt            time.Time `json:"updated_at"`
}

type ClusterSignature struct {
	SchemaVersion  string    `json:"schema_version"`
	Algorithm      string    `json:"algorithm"`
	KeyFingerprint string    `json:"key_fingerprint"`
	Signature      string    `json:"signature"`
	SignedAt       time.Time `json:"signed_at"`
}

type PeerDirectoryEntry struct {
	NodeID            string   `json:"node_id"`
	RouteIDs          []string `json:"route_ids,omitempty"`
	EndpointCount     int      `json:"endpoint_count"`
	CandidateCount    int      `json:"candidate_count"`
	ConnectivityModes []string `json:"connectivity_modes,omitempty"`
	RecoverySeed      bool     `json:"recovery_seed"`
}

type PeerRecoverySeed struct {
	NodeID           string          `json:"node_id"`
	Endpoint         string          `json:"endpoint"`
	Transport        string          `json:"transport"`
	ConnectivityMode string          `json:"connectivity_mode,omitempty"`
	Region           string          `json:"region,omitempty"`
	Priority         int             `json:"priority"`
	LastVerifiedAt   *time.Time      `json:"last_verified_at,omitempty"`
	Metadata         json.RawMessage `json:"metadata,omitempty"`
}

type PeerRendezvousLease struct {
	LeaseID          string          `json:"lease_id"`
	PeerNodeID       string          `json:"peer_node_id"`
	RelayNodeID      string          `json:"relay_node_id"`
	RelayEndpoint    string          `json:"relay_endpoint"`
	Transport        string          `json:"transport"`
	ConnectivityMode string          `json:"connectivity_mode,omitempty"`
	RouteIDs         []string        `json:"route_ids,omitempty"`
	AllowedChannels  []string        `json:"allowed_channels,omitempty"`
	Priority         int             `json:"priority"`
	ControlPlaneOnly bool            `json:"control_plane_only"`
	IssuedAt         time.Time       `json:"issued_at"`
	ExpiresAt        time.Time       `json:"expires_at"`
	Reason           string          `json:"reason,omitempty"`
	Metadata         json.RawMessage `json:"metadata,omitempty"`
}

type RendezvousRelayPolicyDecision struct {
	RouteID          string   `json:"route_id,omitempty"`
	PeerNodeID       string   `json:"peer_node_id"`
	WithdrawnLeaseID string   `json:"withdrawn_lease_id,omitempty"`
	StaleRelayNodeID string   `json:"stale_relay_node_id,omitempty"`
	SelectedRelayID  string   `json:"selected_relay_id,omitempty"`
	SelectedEndpoint string   `json:"selected_endpoint,omitempty"`
	Score            int      `json:"score,omitempty"`
	Reason           string   `json:"reason"`
	ScoreReasons     []string `json:"score_reasons,omitempty"`
	ReporterNodeID   string   `json:"reporter_node_id,omitempty"`
}

type RendezvousRelayPolicyReport struct {
	SchemaVersion         string                          `json:"schema_version"`
	ScoringMode           string                          `json:"scoring_mode"`
	FeedbackMaxAgeSeconds int                             `json:"feedback_max_age_seconds"`
	StaleRelayCount       int                             `json:"stale_relay_count"`
	WithdrawnLeaseCount   int                             `json:"withdrawn_lease_count"`
	ReplacementLeaseCount int                             `json:"replacement_lease_count"`
	Decisions             []RendezvousRelayPolicyDecision `json:"decisions,omitempty"`
}

type RoutePathDecision struct {
	DecisionID            string    `json:"decision_id"`
	RouteID               string    `json:"route_id"`
	ClusterID             string    `json:"cluster_id"`
	LocalNodeID           string    `json:"local_node_id"`
	SourceNodeID          string    `json:"source_node_id"`
	DestinationNodeID     string    `json:"destination_node_id"`
	OriginalHops          []string  `json:"original_hops"`
	EffectiveHops         []string  `json:"effective_hops"`
	PreviousHopID         string    `json:"previous_hop_id,omitempty"`
	NextHopID             string    `json:"next_hop_id,omitempty"`
	LocalRole             string    `json:"local_role"`
	SelectedRelayID       string    `json:"selected_relay_id,omitempty"`
	SelectedRelayEndpoint string    `json:"selected_relay_endpoint,omitempty"`
	StaleRelayNodeID      string    `json:"stale_relay_node_id,omitempty"`
	RendezvousPeerNodeID  string    `json:"rendezvous_peer_node_id,omitempty"`
	RendezvousLeaseID     string    `json:"rendezvous_lease_id,omitempty"`
	RendezvousLeaseReason string    `json:"rendezvous_lease_reason,omitempty"`
	DecisionSource        string    `json:"decision_source"`
	Generation            string    `json:"generation"`
	PathScore             int       `json:"path_score,omitempty"`
	ScoreReasons          []string  `json:"score_reasons,omitempty"`
	ControlPlaneOnly      bool      `json:"control_plane_only"`
	ProductionForwarding  bool      `json:"production_forwarding"`
	ExpiresAt             time.Time `json:"expires_at"`
}

type RoutePathDecisionReport struct {
	SchemaVersion            string              `json:"schema_version"`
	DecisionMode             string              `json:"decision_mode"`
	Generation               string              `json:"generation"`
	DecisionCount            int                 `json:"decision_count"`
	ReplacementDecisionCount int                 `json:"replacement_decision_count"`
	ControlPlaneOnly         bool                `json:"control_plane_only"`
	ProductionForwarding     bool                `json:"production_forwarding"`
	Decisions                []RoutePathDecision `json:"decisions,omitempty"`
}

type PeerEndpointCandidate struct {
	EndpointID       string          `json:"endpoint_id"`
	NodeID           string          `json:"node_id"`
	Transport        string          `json:"transport"`
	Address          string          `json:"address"`
	AddressFamily    string          `json:"address_family,omitempty"`
	Reachability     string          `json:"reachability"`
	NATType          string          `json:"nat_type,omitempty"`
	ConnectivityMode string          `json:"connectivity_mode"`
	Region           string          `json:"region,omitempty"`
	Priority         int             `json:"priority"`
	PolicyTags       []string        `json:"policy_tags,omitempty"`
	LastVerifiedAt   *time.Time      `json:"last_verified_at,omitempty"`
	Metadata         json.RawMessage `json:"metadata,omitempty"`
}

func New(baseURL string) *Client {
	return &Client{
		baseURL: baseURL,
		httpClient: &http.Client{
			Timeout: 15 * time.Second,
		},
	}
}

func (c *Client) Enroll(ctx context.Context, request EnrollRequest) (EnrollResponse, error) {
	var response EnrollResponse
	if err := c.postJSON(ctx, "/node-agents/enroll", request, &response); err != nil {
		return EnrollResponse{}, err
	}
	return response, nil
}

func (c *Client) BootstrapEnrollment(ctx context.Context, joinRequestID string, request EnrollmentBootstrapRequest) (EnrollmentBootstrapResponse, error) {
	var response EnrollmentBootstrapResponse
	path := fmt.Sprintf("/node-agents/enrollments/%s/bootstrap", joinRequestID)
	if err := c.postJSON(ctx, path, request, &response); err != nil {
		return EnrollmentBootstrapResponse{}, err
	}
	return response, nil
}

func (c *Client) Heartbeat(ctx context.Context, clusterID, nodeID string, request HeartbeatRequest) (HeartbeatResponse, error) {
	var response HeartbeatResponse
	path := fmt.Sprintf("/clusters/%s/nodes/%s/heartbeats", clusterID, nodeID)
	if err := c.postJSON(ctx, path, request, &response); err != nil {
		return HeartbeatResponse{}, err
	}
	return response, nil
}

func (c *Client) DesiredWorkloads(ctx context.Context, clusterID, nodeID string) ([]DesiredWorkload, error) {
	var response struct {
		DesiredWorkloads []DesiredWorkload `json:"desired_workloads"`
	}
	path := fmt.Sprintf("/clusters/%s/nodes/%s/workloads/desired", clusterID, nodeID)
	if err := c.getJSON(ctx, path, &response); err != nil {
		return nil, err
	}
	return response.DesiredWorkloads, nil
}

func (c *Client) ReportWorkloadStatus(ctx context.Context, clusterID, nodeID, serviceType string, request WorkloadStatusRequest) error {
	path := fmt.Sprintf("/clusters/%s/nodes/%s/workloads/%s/status", clusterID, nodeID, serviceType)
	return c.postJSON(ctx, path, request, nil)
}

func (c *Client) ReportMeshLink(ctx context.Context, clusterID string, request MeshLinkObservationRequest) error {
	path := fmt.Sprintf("/clusters/%s/mesh/links", clusterID)
	return c.postJSON(ctx, path, request, nil)
}

func (c *Client) ReportTelemetry(ctx context.Context, clusterID, nodeID string, request TelemetryRequest) error {
	path := fmt.Sprintf("/clusters/%s/nodes/%s/telemetry", clusterID, nodeID)
	return c.postJSON(ctx, path, request, nil)
}

func (c *Client) SyntheticMeshConfig(ctx context.Context, clusterID, nodeID string) (SyntheticMeshConfig, error) {
	var response struct {
		Config SyntheticMeshConfig `json:"synthetic_mesh_config"`
	}
	path := fmt.Sprintf("/clusters/%s/nodes/%s/mesh/synthetic-config", clusterID, nodeID)
	if err := c.getJSON(ctx, path, &response); err != nil {
		return SyntheticMeshConfig{}, err
	}
	return response.Config, nil
}

func (c *Client) getJSON(ctx context.Context, path string, response any) error {
	httpReq, err := http.NewRequestWithContext(ctx, http.MethodGet, c.baseURL+path, nil)
	if err != nil {
		return err
	}
	httpResp, err := c.httpClient.Do(httpReq)
	if err != nil {
		return err
	}
	defer httpResp.Body.Close()
	if httpResp.StatusCode < 200 || httpResp.StatusCode >= 300 {
		return fmt.Errorf("backend returned status %d", httpResp.StatusCode)
	}
	if response == nil {
		return nil
	}
	return json.NewDecoder(httpResp.Body).Decode(response)
}

func (c *Client) postJSON(ctx context.Context, path string, request any, response any) error {
	payload, err := json.Marshal(request)
	if err != nil {
		return err
	}
	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, c.baseURL+path, bytes.NewReader(payload))
	if err != nil {
		return err
	}
	httpReq.Header.Set("Content-Type", "application/json")
	httpResp, err := c.httpClient.Do(httpReq)
	if err != nil {
		return err
	}
	defer httpResp.Body.Close()
	if httpResp.StatusCode < 200 || httpResp.StatusCode >= 300 {
		return fmt.Errorf("backend returned status %d", httpResp.StatusCode)
	}
	if response == nil {
		return nil
	}
	return json.NewDecoder(httpResp.Body).Decode(response)
}