package cli

import (
	"context"
	"database/sql"
	"encoding/json"
	"fmt"
	"log/slog"
	"os"
	"os/signal"
	"path/filepath"
	"syscall"
	"time"

	"github.com/google/uuid"
	"github.com/spf13/cobra"

	"git.cloudinit.dev/coreci/orca/internal/certpaths"
	"git.cloudinit.dev/coreci/orca/internal/engine"
	"git.cloudinit.dev/coreci/orca/internal/model"
	"git.cloudinit.dev/coreci/orca/internal/security"
	"git.cloudinit.dev/coreci/orca/internal/store"
)

func dbPath() string {
	if p := os.Getenv("ORCA_DB"); p != "" {
		return p
	}
	home, _ := os.UserHomeDir()
	return filepath.Join(home, ".orca", "orca.db")
}

func openDB() (*sql.DB, func() error, error) {
	db, err := store.Open(dbPath())
	if err != nil {
		return nil, nil, err
	}
	return db, db.Close, nil
}

func newLogger() *slog.Logger {
	return slog.New(slog.NewJSONHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelInfo}))
}

func nodeRegistry() (*engine.NodeRegistry, func() error, error) {
	db, closer, err := openDB()
	if err != nil {
		return nil, nil, err
	}
	repo := store.NewNodeRepo(db)
	audit := engine.NewAudit(store.NewAuditRepo(db), newLogger())
	return engine.NewNodeRegistry(repo, audit, newLogger()), closer, nil
}

var (
	joinName     string
	joinAddr     string
	joinCAFinger string
	leaveID      string
	nodeWatch    bool
)

var nodeCmd = &cobra.Command{
	Use:   "node",
	Short: "Manage orca nodes",
	Long:  "Join, leave, or list orca nodes in the registry.",
}

var nodeJoinCmd = &cobra.Command{
	Use:   "join",
	Short: "Join a node to the orca registry",
	Long:  "Register a node in the local orca registry. Persisted to SQLite.",
	RunE: func(cmd *cobra.Command, args []string) error {
		if joinName == "" {
			return fmt.Errorf("--name is required")
		}
		if joinAddr == "" {
			joinAddr = "localhost:8443"
		}

		// REQ-026: if --ca-fingerprint is set, verify the on-disk CA
		// matches the pinned value before we touch the registry. This
		// prevents typos in the operator-supplied fingerprint from
		// silently degrading to "no pin" and accepting any cert.
		if joinCAFinger != "" {
			fp, err := security.Fingerprint(certpaths.CACertPath())
			if err != nil {
				return fmt.Errorf("--ca-fingerprint set but local CA is missing: %w (run `orca cert ca-init` first)", err)
			}
			if fp != joinCAFinger {
				return fmt.Errorf(
					"CA fingerprint mismatch: on-disk=%s, pinned=%s — refusing to join (REQ-026)",
					fp, joinCAFinger,
				)
			}
		}

		ctx, cancel := context.WithTimeout(cmd.Context(), 5*time.Second)
		defer cancel()

		registry, closer, err := nodeRegistry()
		if err != nil {
			return err
		}
		defer closer()

		node := &model.Node{
			ID:       uuid.NewString(),
			Name:     joinName,
			Address:  joinAddr,
			State:    model.NodeStateReady,
			JoinedAt: time.Now().UTC(),
			LastSeen: time.Now().UTC(),
		}
		if err := registry.Join(ctx, node); err != nil {
			return err
		}
		if jsonOutput {
			return printJSON(node)
		}
		fmt.Fprintf(cmd.OutOrStdout(), "✓ Node joined: %s (%s) at %s\n", node.ID, node.Name, node.Address)
		return nil
	},
}

var nodeLeaveCmd = &cobra.Command{
	Use:   "leave [node-id]",
	Short: "Remove a node from the orca registry",
	Long:  "Mark a node as left. Use --id to specify, or pass as argument.",
	Args:  cobra.MaximumNArgs(1),
	RunE: func(cmd *cobra.Command, args []string) error {
		id := leaveID
		if id == "" && len(args) > 0 {
			id = args[0]
		}
		if id == "" {
			return fmt.Errorf("node id required (use --id or pass as argument)")
		}
		ctx, cancel := context.WithTimeout(cmd.Context(), 5*time.Second)
		defer cancel()

		registry, closer, err := nodeRegistry()
		if err != nil {
			return err
		}
		defer closer()

		if err := registry.Leave(ctx, id); err != nil {
			return err
		}
		if jsonOutput {
			return printJSON(map[string]string{"id": id, "state": "left"})
		}
		fmt.Fprintf(cmd.OutOrStdout(), "✓ Node left: %s\n", id)
		return nil
	},
}

var nodeListCmd = &cobra.Command{
	Use:   "list",
	Short: "List all nodes in the orca registry",
	Long:  "Display all registered nodes and their state. Use --watch to stream updates until Ctrl-C.",
	RunE: func(cmd *cobra.Command, args []string) error {
		if nodeWatch {
			return watchNodes(cmd)
		}
		ctx, cancel := context.WithTimeout(cmd.Context(), 5*time.Second)
		defer cancel()

		registry, closer, err := nodeRegistry()
		if err != nil {
			return err
		}
		defer closer()

		nodes, err := registry.List(ctx)
		if err != nil {
			return err
		}
		if jsonOutput {
			return printJSON(nodes)
		}
		if len(nodes) == 0 {
			fmt.Fprintln(cmd.OutOrStdout(), "No nodes registered. Use 'orca node join' to add one.")
			return nil
		}
		fmt.Fprintf(cmd.OutOrStdout(), "%-36s  %-20s  %-22s  %-10s\n", "ID", "NAME", "ADDRESS", "STATE")
		for _, n := range nodes {
			fmt.Fprintf(cmd.OutOrStdout(), "%-36s  %-20s  %-22s  %-10s\n", n.ID, n.Name, n.Address, n.State)
		}
		return nil
	},
}

func watchNodes(cmd *cobra.Command) error {
	ctx, cancel := signal.NotifyContext(cmd.Context(), os.Interrupt, syscall.SIGTERM)
	defer cancel()
	return watchNodesCtx(cmd, ctx)
}

func watchNodesCtx(cmd *cobra.Command, ctx context.Context) error {
	db, closer, err := openDB()
	if err != nil {
		return err
	}
	defer closer()

	out := cmd.OutOrStdout()

	if jsonOutput {
		seen := make(map[string]string)
		for snapshot := range store.NewNodeRepo(db).Watch(ctx) {
			current := make(map[string]bool, len(snapshot))
			for _, n := range snapshot {
				current[n.ID] = true
				compact, _ := json.Marshal(n)
				key := string(compact)
				if prev, ok := seen[n.ID]; !ok || prev != key {
					event := "init"
					if ok {
						event = "update"
					}
					line, _ := json.Marshal(map[string]any{"event": event, "node": n})
					fmt.Fprintln(out, string(line))
					seen[n.ID] = key
				}
			}
			for id := range seen {
				if !current[id] {
					line, _ := json.Marshal(map[string]any{"event": "delete", "id": id})
					fmt.Fprintln(out, string(line))
					delete(seen, id)
				}
			}
		}
		return nil
	}

	prevTable := ""
	for snapshot := range store.NewNodeRepo(db).Watch(ctx) {
		table := renderNodeTable(snapshot)
		if table != prevTable {
			fmt.Fprint(out, "\033[2J\033[H")
			fmt.Fprint(out, table)
			prevTable = table
		}
	}
	return nil
}

func renderNodeTable(nodes []*model.Node) string {
	if len(nodes) == 0 {
		return "No nodes registered.\n"
	}
	out := fmt.Sprintf("%-36s  %-20s  %-22s  %-10s\n", "ID", "NAME", "ADDRESS", "STATE")
	for _, n := range nodes {
		out += fmt.Sprintf("%-36s  %-20s  %-22s  %-10s\n", n.ID, n.Name, n.Address, n.State)
	}
	return out
}

func init() {
	nodeJoinCmd.Flags().StringVar(&joinName, "name", "", "node name (required)")
	nodeJoinCmd.Flags().StringVar(&joinAddr, "addr", "", "node address (default localhost:8443)")
	nodeJoinCmd.Flags().StringVar(&joinCAFinger, "ca-fingerprint", "", "pin CA cert SHA-256 (REQ-026); fails if on-disk CA doesn't match")
	nodeLeaveCmd.Flags().StringVar(&leaveID, "id", "", "node id")
	nodeListCmd.Flags().BoolVar(&nodeWatch, "watch", false, "stream nodes until Ctrl-C (table refresh or --json per-event)")

	nodeCmd.AddCommand(nodeJoinCmd)
	nodeCmd.AddCommand(nodeLeaveCmd)
	nodeCmd.AddCommand(nodeListCmd)
	rootCmd.AddCommand(nodeCmd)
}