package http

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

	"github.com/go-chi/chi/v5"
	"github.com/oklog/ulid/v2"

	"gitea.dcglab.co.uk/steve/restic-manager/internal/api"
	"gitea.dcglab.co.uk/steve/restic-manager/internal/auth"
	"gitea.dcglab.co.uk/steve/restic-manager/internal/store"
)

// runNowRequest is the body of POST /api/hosts/:id/jobs.
type runNowRequest struct {
	Kind  api.JobKind `json:"kind"`
	Args  []string    `json:"args,omitempty"`  // restic CLI args (paths for backup, etc.)
}

type runNowResponse struct {
	JobID  string `json:"job_id"`
	Status string `json:"status"` // "queued"
}

// handleRunNow dispatches a job to the named host. Authenticated;
// rejects if the host isn't connected (caller should retry once
// the agent comes back).
func (s *Server) handleRunNow(w stdhttp.ResponseWriter, r *stdhttp.Request) {
	user, ok := s.requireUser(r)
	if !ok {
		writeJSONError(w, stdhttp.StatusUnauthorized, "unauthorized", "")
		return
	}
	hostID := chi.URLParam(r, "id")
	if hostID == "" {
		writeJSONError(w, stdhttp.StatusBadRequest, "missing_host_id", "")
		return
	}
	var req runNowRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeJSONError(w, stdhttp.StatusBadRequest, "invalid_json", err.Error())
		return
	}

	res, status, code, msg := s.dispatchJob(r.Context(), user, hostID, req.Kind, req.Args)
	if code != "" {
		writeJSONError(w, status, code, msg)
		return
	}
	writeJSON(w, stdhttp.StatusAccepted, res)
}

// dispatchJob is the common path for HTTP-driven job dispatch. It
// validates the kind, checks the host is online, persists the job
// row, and ships command.run over the WS. Returns:
//   - res: the queued-job response (job_id + status)
//   - status: HTTP status to return on failure (or 0 on success)
//   - code, msg: error code/message for the wire (empty on success)
//
// JSON callers wrap with writeJSONError; HTML callers translate to
// flash banner + redirect.
func (s *Server) dispatchJob(ctx context.Context, user *store.User,
	hostID string, kind api.JobKind, args []string,
) (res runNowResponse, status int, code, msg string) {
	if !validJobKind(kind) {
		return res, stdhttp.StatusBadRequest, "invalid_kind",
			"kind must be one of backup|forget|prune|check|unlock"
	}
	host, err := s.deps.Store.GetHost(ctx, hostID)
	if err != nil {
		return res, stdhttp.StatusNotFound, "host_not_found", ""
	}
	if !s.deps.Hub.Connected(host.ID) {
		return res, stdhttp.StatusServiceUnavailable, "host_offline",
			"agent is not currently connected; try again when it reconnects"
	}

	jobID := ulid.Make().String()
	now := time.Now().UTC()
	if err := s.deps.Store.CreateJob(ctx, store.Job{
		ID:        jobID,
		HostID:    host.ID,
		Kind:      string(kind),
		ActorKind: "user",
		ActorID:   &user.ID,
		CreatedAt: now,
	}); err != nil {
		return res, stdhttp.StatusInternalServerError, "internal", ""
	}

	env, err := api.Marshal(api.MsgCommandRun, jobID, api.CommandRunPayload{
		JobID: jobID,
		Kind:  kind,
		Args:  args,
	})
	if err != nil {
		return res, stdhttp.StatusInternalServerError, "internal", ""
	}
	if err := s.deps.Hub.Send(ctx, host.ID, env); err != nil {
		return res, stdhttp.StatusServiceUnavailable, "host_offline", err.Error()
	}

	_ = s.deps.Store.AppendAudit(ctx, store.AuditEntry{
		ID:         ulid.Make().String(),
		UserID:     &user.ID,
		Actor:      "user",
		Action:     "job.run_now",
		TargetKind: ptr("job"),
		TargetID:   &jobID,
		TS:         now,
	})
	return runNowResponse{JobID: jobID, Status: "queued"}, 0, "", ""
}

// requireUser resolves the session cookie to a user row. Stub of the
// session-auth middleware that lands in P1-04's full pass.
func (s *Server) requireUser(r *stdhttp.Request) (*store.User, bool) {
	c, err := r.Cookie(sessionCookieName)
	if err != nil {
		return nil, false
	}
	sess, err := s.deps.Store.LookupSession(r.Context(), auth.HashToken(c.Value))
	if err != nil {
		return nil, false
	}
	u, err := s.deps.Store.GetUserByID(r.Context(), sess.UserID)
	if err != nil {
		return nil, false
	}
	return u, true
}

func validJobKind(k api.JobKind) bool {
	switch k {
	case api.JobBackup, api.JobInit, api.JobForget, api.JobPrune, api.JobCheck, api.JobUnlock:
		return true
	}
	return false
}