// Package security exposes admin-only HTTP endpoints for secret/key management:
// rotating the master key (bumping crypto_keys active version + enqueuing the
// re-encrypt job) and reporting re-encryption progress. All routes sit behind
// middleware.Auth + an explicit is_admin gate (reusing the userAdminAdapter
// pattern shared across the codebase), so an agent / non-admin token cannot
// trigger a rotation.
package security

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

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

	"github.com/yan1h/agent-coding-workflow/internal/audit"
	"github.com/yan1h/agent-coding-workflow/internal/infra/errs"
	"github.com/yan1h/agent-coding-workflow/internal/jobs"
	"github.com/yan1h/agent-coding-workflow/internal/jobs/handlers"
	httpx "github.com/yan1h/agent-coding-workflow/internal/transport/http"
	"github.com/yan1h/agent-coding-workflow/internal/transport/http/middleware"
)

// AdminLookup resolves is_admin for a user (same narrow interface used across
// handlers; the shared userAdminAdapter satisfies it).
type AdminLookup interface {
	IsAdmin(ctx context.Context, id uuid.UUID) (bool, error)
}

// KeyRotator bumps the active crypto key version. The Postgres key store
// satisfies this.
type KeyRotator interface {
	RotateActive(ctx context.Context, provider, keyRef string) (int, error)
	ActiveVersion(ctx context.Context) (int, error)
}

// JobEnqueuer enqueues background jobs. jobs.Repository satisfies it.
type JobEnqueuer interface {
	Enqueue(ctx context.Context, typ jobs.JobType, payload json.RawMessage, scheduledAt time.Time, maxAttempts int32) (*jobs.Job, error)
}

// StatusReporter reports re-encryption progress per table. The Postgres
// re-encrypt store satisfies it.
type StatusReporter interface {
	Tables() []string
	StaleCount(ctx context.Context, table string, activeVersion int) (int, error)
}

// Handler wires the security admin endpoints.
type Handler struct {
	rotator  KeyRotator
	enqueuer JobEnqueuer
	status   StatusReporter
	resolver middleware.SessionResolver
	users    AdminLookup
	audit    audit.Recorder
}

// NewHandler constructs the security Handler. audit may be nil (best-effort).
func NewHandler(rotator KeyRotator, enqueuer JobEnqueuer, status StatusReporter,
	resolver middleware.SessionResolver, users AdminLookup, rec audit.Recorder) *Handler {
	return &Handler{rotator: rotator, enqueuer: enqueuer, status: status, resolver: resolver, users: users, audit: rec}
}

// Mount registers the admin security routes under middleware.Auth.
func (h *Handler) Mount(r chi.Router) {
	auth := middleware.Auth(h.resolver, middleware.AuthOptions{})
	r.With(auth).Route("/api/v1/admin/security", func(r chi.Router) {
		r.Post("/rotate-key", h.rotateKey)
		r.Get("/reencrypt-status", h.reencryptStatus)
	})
}

// requireAdmin resolves the actor and enforces is_admin.
func (h *Handler) requireAdmin(r *http.Request) (uuid.UUID, error) {
	uid, ok := middleware.UserIDFromContext(r.Context())
	if !ok {
		return uuid.Nil, errs.New(errs.CodeUnauthorized, "unauthenticated")
	}
	isAdmin, err := h.users.IsAdmin(r.Context(), uid)
	if err != nil {
		return uuid.Nil, err
	}
	if !isAdmin {
		return uuid.Nil, errs.New(errs.CodeForbidden, "需要管理员权限")
	}
	return uid, nil
}

// rotateKeyReq is the optional request body for POST /rotate-key.
type rotateKeyReq struct {
	Provider string `json:"provider"` // 默认 env
	KeyRef   string `json:"key_ref"`  // KMS/Vault 引用，env provider 留空
}

// rotateKeyResp reports the new active version and the enqueued job.
type rotateKeyResp struct {
	ActiveVersion int    `json:"active_version"`
	JobID         string `json:"job_id"`
}

// rotateKey bumps the active key version and enqueues the re-encrypt job. The
// new version's key material must already be loadable by the provider (e.g.
// APP_MASTER_KEY_V<n> staged) — otherwise the re-encrypt job's seals will fail
// and the job retries until the operator stages the key. The OLD version stays
// loadable so existing blobs decrypt during the rotation window.
func (h *Handler) rotateKey(w http.ResponseWriter, r *http.Request) {
	actor, err := h.requireAdmin(r)
	if err != nil {
		h.writeErr(w, r, err)
		return
	}
	var req rotateKeyReq
	if r.Body != nil {
		_ = json.NewDecoder(r.Body).Decode(&req) // body optional
	}
	provider := req.Provider
	if provider == "" {
		provider = "env"
	}

	newVer, err := h.rotator.RotateActive(r.Context(), provider, req.KeyRef)
	if err != nil {
		h.writeErr(w, r, errs.Wrap(err, errs.CodeInternal, "rotate key"))
		return
	}

	payload, _ := json.Marshal(handlers.SecretReencryptPayload{ActiveVersion: newVer})
	job, err := h.enqueuer.Enqueue(r.Context(), jobs.TypeSecretReencrypt, payload, time.Now(), 5)
	if err != nil {
		h.writeErr(w, r, errs.Wrap(err, errs.CodeInternal, "enqueue reencrypt"))
		return
	}

	if h.audit != nil {
		a := actor
		_ = h.audit.Record(context.WithoutCancel(r.Context()), audit.Entry{
			UserID:     &a,
			Action:     "security.rotate_key",
			TargetType: "crypto_key",
			TargetID:   job.ID.String(),
			Metadata:   map[string]any{"active_version": newVer, "job_id": job.ID.String()},
		})
	}

	httpx.WriteJSON(w, http.StatusAccepted, rotateKeyResp{ActiveVersion: newVer, JobID: job.ID.String()})
}

// reencryptStatusResp reports rows remaining on a stale key version per table.
type reencryptStatusResp struct {
	ActiveVersion int            `json:"active_version"`
	Stale         map[string]int `json:"stale"`
	Complete      bool           `json:"complete"`
}

// reencryptStatus reports per-table counts of rows still on an old key version.
func (h *Handler) reencryptStatus(w http.ResponseWriter, r *http.Request) {
	if _, err := h.requireAdmin(r); err != nil {
		h.writeErr(w, r, err)
		return
	}
	active, err := h.rotator.ActiveVersion(r.Context())
	if err != nil {
		h.writeErr(w, r, errs.Wrap(err, errs.CodeInternal, "active version"))
		return
	}
	stale := map[string]int{}
	total := 0
	for _, t := range h.status.Tables() {
		n, err := h.status.StaleCount(r.Context(), t, active)
		if err != nil {
			h.writeErr(w, r, errs.Wrap(err, errs.CodeInternal, "stale count"))
			return
		}
		stale[t] = n
		total += n
	}
	httpx.WriteJSON(w, http.StatusOK, reencryptStatusResp{
		ActiveVersion: active,
		Stale:         stale,
		Complete:      total == 0,
	})
}

func (h *Handler) writeErr(w http.ResponseWriter, r *http.Request, err error) {
	httpx.WriteError(w, middleware.RequestIDFromContext(r.Context()), err)
}