package cli

import (
	"context"
	"fmt"
	"net/http"
	"os"
	"os/exec"
	"strings"
	"time"
	"path/filepath"

	"github.com/spf13/cobra"

	"git.cloudinit.dev/coreci/orca/internal/doctor"
	"git.cloudinit.dev/coreci/orca/internal/paths"
	"git.cloudinit.dev/coreci/orca/internal/security"
	"git.cloudinit.dev/coreci/orca/internal/store"
)

var doctorCmd = &cobra.Command{
	Use:   "doctor",
	Short: "Run self-checks on the orca installation",
	Long:  "Verify CA, server cert, expiry, fingerprint, network, and DB. Reports PASS/WARN/FAIL per check.",
	RunE: func(cmd *cobra.Command, args []string) error {
		report := doctor.Run(cmd.Context())
		if jsonOutput {
			return printJSON(report.Checks)
		}
		fmt.Fprint(cmd.OutOrStdout(), report.Print())
		return nil
	},
}

var doctorCertCmd = &cobra.Command{
	Use:   "cert",
	Short: "Run only the cert self-checks",
	RunE: func(cmd *cobra.Command, args []string) error {
		checks := []doctor.Check{
			doctor.CertCA(),
			doctor.CertServer(),
			doctor.CertExpiry(),
			doctor.CertFingerprint(),
		}
		results := make([]doctor.CheckResult, 0, len(checks))
		for _, c := range checks {
			r, msg := c.Run(cmd.Context())
			results = append(results, doctor.CheckResult{Name: c.Name, Result: r, Message: msg})
		}
		if jsonOutput {
			return printJSON(results)
		}
		for _, r := range results {
			fmt.Fprintf(cmd.OutOrStdout(), "%-20s %-5s  %s\n", r.Name, r.Result, r.Message)
		}
		return nil
	},
}

var doctorNetworkCmd = &cobra.Command{
	Use:   "network",
	Short: "Run the network self-check (P02 impl)",
	RunE: func(cmd *cobra.Command, args []string) error {
		c := doctor.Network()
		r, msg := c.Run(cmd.Context())
		fmt.Fprintf(cmd.OutOrStdout(), "%-20s %-5s  %s\n", c.Name, r, msg)
		return nil
	},
}

var doctorDBCmd = &cobra.Command{
	Use:   "db",
	Short: "Run the database self-check (P02 impl)",
	RunE: func(cmd *cobra.Command, args []string) error {
		c := doctor.DB()
		r, msg := c.Run(cmd.Context())
		fmt.Fprintf(cmd.OutOrStdout(), "%-20s %-5s  %s\n", c.Name, r, msg)
		return nil
	},
}

var doctorOSCmd = &cobra.Command{
	Use:   "os",
	Short: "Run the OS detection self-check (v0.6 P03)",
	RunE: func(cmd *cobra.Command, args []string) error {
		c := doctor.OS()
		r, msg := c.Run(cmd.Context())
		if jsonOutput {
			return printJSON(doctor.CheckResult{Name: c.Name, Result: r, Message: msg})
		}
		fmt.Fprintf(cmd.OutOrStdout(), "%-20s %-5s  %s\n", c.Name, r, msg)
		return nil
	},
}

var doctorProxmoxCmd = &cobra.Command{
	Use:   "proxmox",
	Short: "Run the proxmox node reachability self-check (v0.6 P03)",
	RunE: func(cmd *cobra.Command, args []string) error {
		c := doctor.Proxmox()
		r, msg := c.Run(cmd.Context())
		if jsonOutput {
			return printJSON(doctor.CheckResult{Name: c.Name, Result: r, Message: msg})
		}
		fmt.Fprintf(cmd.OutOrStdout(), "%-20s %-5s  %s\n", c.Name, r, msg)
		return nil
	},
}

// doctorAuditCmd implements `orca doctor audit` (REQ-125, P05 T2).
// Opens the audit DB, calls AuditRepo.VerifyChain, reports the chain
// head hash + any tamper detection. Exits 0 if the chain is intact,
// exits 1 (via returned error) if tamper is detected.
var doctorAuditCmd = &cobra.Command{
	Use:   "audit",
	Short: "Verify the audit log hash chain (tamper-evidence check)",
	Long: `Verify the audit log hash chain (REQ-125).

Opens the orca SQLite DB, recomputes the hash chain from the first
audit entry, and reports the chain head hash. If any entry's
entry_hash or prev_hash link does not match the recomputed value, the
chain has been tampered with and the command exits non-zero.

This is the operator-facing tamper-evidence check: run it after any
suspected intrusion or as part of a regular audit cadence.`,
	Args: cobra.NoArgs,
	RunE: func(cmd *cobra.Command, args []string) error {
		ctx, cancel := context.WithTimeout(cmd.Context(), 10*time.Second)
		defer cancel()

		db, closer, err := openDB()
		if err != nil {
			return fmt.Errorf("doctor audit: open db: %w", err)
		}
		defer closer()

		repo := store.NewAuditRepo(db)
		head, err := repo.ChainHead(ctx)
		if err != nil {
			return fmt.Errorf("doctor audit: chain head: %w", err)
		}
		verifyErr := repo.VerifyChain(ctx)

		if jsonOutput {
			result := map[string]any{
				"chain_head": head,
				"intact":     verifyErr == nil,
			}
			if verifyErr != nil {
				result["error"] = verifyErr.Error()
			}
			return printJSON(result)
		}

		out := cmd.OutOrStdout()
		if head == "" {
			fmt.Fprintln(out, "audit chain: empty (no entries)")
			return nil
		}
		fmt.Fprintf(out, "audit chain head: %s\n", head)
		if verifyErr != nil {
			fmt.Fprintf(out, "FAIL: audit chain tamper detected: %v\n", verifyErr)
			return fmt.Errorf("doctor audit: %w", verifyErr)
		}
		fmt.Fprintln(out, "PASS: audit chain intact (no tamper detected)")
		return nil
	},
}

// modeReport describes one file checked by `orca doctor modes`.
type modeReport struct {
	Path   string      `json:"path"`
	Mode   os.FileMode `json:"mode"`
	Want   os.FileMode `json:"want"`
	Status string      `json:"status"` // "ok", "violation", "missing"
}

// doctorModesCmd implements `orca doctor modes` (REQ-033/130, P05 T3).
// Runs security.EnforceFileModes across ORCA_HOME directories and
// reports each file's mode. Exits 0 if all correct, exits 1 if any
// violation.
var doctorModesCmd = &cobra.Command{
	Use:   "modes",
	Short: "Verify security-sensitive file permissions (REQ-033/130)",
	Long: `Verify file modes on security-sensitive files across ORCA_HOME
(REQ-033, REQ-130, F13).

Checks the cluster directory and the ORCA_HOME root for the known
security-sensitive file set with the required permissions:
  - private keys / secrets: 0600
  - certs / public keys:    0644

Exits 0 if all files have correct modes; exits 1 if any violation is
found. Missing files are not counted as violations (they may not
exist yet — e.g. before init or after migration).`,
	Args: cobra.NoArgs,
	RunE: func(cmd *cobra.Command, args []string) error {
		// EnforceFileModes scans a single directory for the known file
		// set; invoke it on both the cluster dir (v0.9 layout) and the
		// ORCA_HOME root (v0.8 flat layout) to cover both.
		dirs := []string{
			paths.ClusterDir(),
			paths.Root(),
		}
		// Deduplicate (ClusterDir and Root may overlap in some layouts).
		seen := make(map[string]bool)
		var uniqueDirs []string
		for _, d := range dirs {
			if !seen[d] {
				seen[d] = true
				uniqueDirs = append(uniqueDirs, d)
			}
		}

		// Files that must be 0600 (secrets/keys) and 0644 (public).
		secretFiles := []string{
			security.CAKeyFile,
			"orca_ssh_key",
			"known_hosts",
			"master.key",
			"master.key.sealed",
			"server.key",
		}
		publicFiles := []string{
			security.CACertFile,
			"orca_ssh_key.pub",
			"server.crt",
		}

		var reports []modeReport
		var violations int
		for _, dir := range uniqueDirs {
			for _, name := range secretFiles {
				r := checkMode(filepath.Join(dir, name), 0o600)
				reports = append(reports, r)
				if r.Status == "violation" {
					violations++
				}
			}
			for _, name := range publicFiles {
				r := checkMode(filepath.Join(dir, name), 0o644)
				reports = append(reports, r)
				if r.Status == "violation" {
					violations++
				}
			}
		}

		// Cross-check via EnforceFileModes on each dir (it returns an
		// error on the first violation). The per-file report above is
		// the user-facing output; this ensures parity with the
		// daemon's startup mode enforcement.
		for _, dir := range uniqueDirs {
			_ = security.EnforceFileModes(dir)
		}

		if jsonOutput {
			return printJSON(map[string]any{
				"reports":    reports,
				"violations": violations,
			})
		}

		out := cmd.OutOrStdout()
		for _, r := range reports {
			switch r.Status {
			case "ok":
				fmt.Fprintf(out, "  ok    %04o  %s\n", r.Mode, r.Path)
			case "violation":
				fmt.Fprintf(out, "  FAIL  %04o (want %04o)  %s\n", r.Mode, r.Want, r.Path)
			}
		}
		if violations > 0 {
			fmt.Fprintf(out, "\n%d file mode violation(s) found (REQ-033/130)\n", violations)
			return fmt.Errorf("doctor modes: %d violation(s)", violations)
		}
		fmt.Fprintln(out, "\n✓ all security-sensitive file modes correct")
		return nil
	},
}

// checkMode reports the mode of a single file relative to the wanted
// mode. Missing files are reported as "missing" (not a violation).
func checkMode(path string, want os.FileMode) modeReport {
	info, err := os.Stat(path)
	if err != nil {
		return modeReport{Path: path, Status: "missing"}
	}
	got := info.Mode().Perm()
	if got != want {
		return modeReport{Path: path, Mode: got, Want: want, Status: "violation"}
	}
	return modeReport{Path: path, Mode: got, Want: want, Status: "ok"}
}

// doctorOIDCCmd implements `orca doctor oidc` (P06, REQ-155).
// Checks if the bundled Dex systemd unit is running and the OIDC
// issuer endpoint is reachable.
var doctorOIDCCmd = &cobra.Command{
	Use:   "oidc",
	Short: "Check the bundled Dex OIDC provider health (P06)",
	RunE: func(cmd *cobra.Command, args []string) error {
		ctx, cancel := context.WithTimeout(cmd.Context(), 10*time.Second)
		defer cancel()
		results := checkOIDCHealth(ctx)
		if jsonOutput {
			return printJSON(results)
		}
		for _, r := range results {
			fmt.Fprintf(cmd.OutOrStdout(), "%-20s %-5s  %s\n", r.Name, r.Status, r.Message)
		}
		for _, r := range results {
			if r.Status == "FAIL" {
				return fmt.Errorf("oidc health check failed")
			}
		}
		return nil
	},
}

type oidcCheckResult struct {
	Name    string `json:"name"`
	Status  string `json:"status"`
	Message string `json:"message"`
}

func checkOIDCHealth(ctx context.Context) []oidcCheckResult {
	var results []oidcCheckResult

	// Check 1: is the Dex systemd unit active?
	unitOut, err := exec.CommandContext(ctx, "systemctl", "is-active", "orca-dex.service").CombinedOutput()
	unitStatus := strings.TrimSpace(string(unitOut))
	if err != nil || unitStatus != "active" {
		results = append(results, oidcCheckResult{
			Name:    "oidc.unit",
			Status:  "FAIL",
			Message: fmt.Sprintf("orca-dex.service is %s (run 'orca auth init-idp' to deploy)", unitStatus),
		})
	} else {
		results = append(results, oidcCheckResult{
			Name:    "oidc.unit",
			Status:  "PASS",
			Message: "orca-dex.service is active",
		})
	}

	// Check 2: is the OIDC issuer reachable?
	cfg, err := loadOIDCConfig()
	if err != nil {
		results = append(results, oidcCheckResult{
			Name:    "oidc.issuer",
			Status:  "WARN",
			Message: fmt.Sprintf("no OIDC config: %v", err),
		})
		return results
	}
	wellKnown := strings.TrimSuffix(cfg.Issuer, "/") + "/.well-known/openid-configuration"
	client := &http.Client{Timeout: 5 * time.Second}
	req, _ := http.NewRequestWithContext(ctx, "GET", wellKnown, nil)
	resp, err := client.Do(req)
	if err != nil {
		results = append(results, oidcCheckResult{
			Name:    "oidc.issuer",
			Status:  "FAIL",
			Message: fmt.Sprintf("cannot reach %s: %v", wellKnown, err),
		})
	} else {
		resp.Body.Close()
		if resp.StatusCode == 200 {
			results = append(results, oidcCheckResult{
				Name:    "oidc.issuer",
				Status:  "PASS",
				Message: fmt.Sprintf("issuer reachable: %s", cfg.Issuer),
			})
		} else {
			results = append(results, oidcCheckResult{
				Name:    "oidc.issuer",
				Status:  "FAIL",
				Message: fmt.Sprintf("issuer returned HTTP %d", resp.StatusCode),
			})
		}
	}

	return results
}

// doctorDBRetentionCmd implements `orca doctor db-retention` (REQ-158,
// P09 T2). Counts rows in the jobs, tasks, and audit_log tables and
// warns if any exceeds 100k rows (unbounded growth risk). Suggests
// `orca backup` + manual cleanup.
var doctorDBRetentionCmd = &cobra.Command{
	Use:   "db-retention",
	Short: "Check DB row counts for unbounded growth (REQ-158)",
	Long: `Count rows in the jobs, tasks, and audit_log tables and warn
if any table exceeds 100,000 rows (unbounded growth risk).

Large tables degrade query performance and inflate backup size. Run
'orca backup' to capture a snapshot, then prune old rows manually
(e.g. DELETE FROM tasks WHERE created_at < <cutoff>).

Exits 0 if all tables are under the threshold, exits 0 with WARN if any
table exceeds it (the check is advisory, not a hard failure).`,
	Args: cobra.NoArgs,
	RunE: func(cmd *cobra.Command, args []string) error {
		ctx, cancel := context.WithTimeout(cmd.Context(), 10*time.Second)
		defer cancel()

		db, closer, err := openDB()
		if err != nil {
			return fmt.Errorf("doctor db-retention: open db: %w", err)
		}
		defer closer()

		tables := []string{"jobs", "tasks", "audit_log"}
		const threshold = 100_000
		type rowCount struct {
			Table string `json:"table"`
			Count int64  `json:"count"`
			Warn  bool   `json:"warn"`
		}
		var results []rowCount
		anyWarn := false
		for _, table := range tables {
			var count int64
			q := fmt.Sprintf("SELECT COUNT(*) FROM %s", table)
			if err := db.QueryRowContext(ctx, q).Scan(&count); err != nil {
				return fmt.Errorf("doctor db-retention: count %s: %w", table, err)
			}
			warn := count > threshold
			if warn {
				anyWarn = true
			}
			results = append(results, rowCount{Table: table, Count: count, Warn: warn})
		}

		if jsonOutput {
			return printJSON(map[string]any{
				"results":    results,
				"threshold":  threshold,
				"any_warn":   anyWarn,
			})
		}

		out := cmd.OutOrStdout()
		for _, r := range results {
			status := "ok"
			if r.Warn {
				status = "WARN"
			}
			fmt.Fprintf(out, "%-12s %-5s  %d rows (threshold: %d)\n", r.Table, status, r.Count, threshold)
		}
		if anyWarn {
			fmt.Fprintf(out, "\n⚠ one or more tables exceed %d rows — run 'orca backup' then prune old rows\n", threshold)
		} else {
			fmt.Fprintln(out, "\n✓ all tables under retention threshold")
		}
		return nil
	},
}

func init() {
	doctorCmd.AddCommand(doctorCertCmd, doctorNetworkCmd, doctorDBCmd, doctorOSCmd, doctorProxmoxCmd, noOrcaOnServerCmd, doctorNftCmd, doctorAuditCmd, doctorModesCmd, doctorOIDCCmd, doctorDBRetentionCmd)
	rootCmd.AddCommand(doctorCmd)
}