package signedjobs

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"log/slog"
	"regexp"
	"strconv"
	"strings"
	"time"

	"gitea.dooplex.hu/admin/felhom-agent/internal/localapi"
	"gitea.dooplex.hu/admin/felhom-agent/internal/proxmox"
)

// opAddInternalPlace is the op class this executor serves (mirrors reconcile.ClassAddInternalPlace).
const opAddInternalPlace = "add_internal_place"

// InternalPlaceHelper is the root helper's path (configs/felhom-internal-place, from the config bundle).
const InternalPlaceHelper = "/usr/local/sbin/felhom-internal-place"

var reHelperResult = regexp.MustCompile(`^(created|existing|formatted) uuid=([0-9a-fA-F-]{36}) gib=([0-9]+)$`)

// InternalPlaceExecutor adds the internal data place to an OLD one-disk box (felhom.eu architecture/16 §9: „one-disk
// boxes get no internal place by themselves; adding one later is a signed operator job, not a household button").
// It runs the SAME root helper the installer runs — `felhom-internal-place create 0` (0 GiB planned: the guest's
// volumes already exist and are counted) — writes the record the agent mounts from, and asks the local API to mount
// it now. Every safety rule (the ruled size, never format what holds anything) lives in the helper, as root.
//
// The op carries no parameters: the size is the rule's, never the signer's. Destructive-class by default (the
// classifier's fail-safe; ClassAddInternalPlace documents it): it takes thin space on the system disk, so only an
// operator signature may start it.
type InternalPlaceExecutor struct {
	runner     proxmox.Runner
	recordFile string
	ensure     func(context.Context) // late-bound: the local API server is built after the jobs runner
	logger     *slog.Logger
}

// NewInternalPlaceExecutor wires the executor. ensure may be nil at construction and set later through SetEnsure.
func NewInternalPlaceExecutor(runner proxmox.Runner, recordFile string, logger *slog.Logger) *InternalPlaceExecutor {
	if logger == nil {
		logger = slog.Default()
	}
	return &InternalPlaceExecutor{runner: runner, recordFile: recordFile, logger: logger}
}

// SetEnsure late-binds the mount step (localapi.Server.EnsureInternalPlace).
func (e *InternalPlaceExecutor) SetEnsure(f func(context.Context)) { e.ensure = f }

// Execute implements signedjobs.Executor for add_internal_place.
func (e *InternalPlaceExecutor) Execute(ctx context.Context, op string, params json.RawMessage) error {
	if op != opAddInternalPlace {
		return ErrNoExecutor
	}
	if p := bytes.TrimSpace(params); len(p) > 0 && !bytes.Equal(p, []byte("{}")) && !bytes.Equal(p, []byte("null")) {
		return fmt.Errorf("add_internal_place: takes no parameters (the size is the ruled rule's), got %s", p)
	}
	if e.runner == nil || e.recordFile == "" {
		return fmt.Errorf("add_internal_place: not wired on this host (no privileged runner or state dir)")
	}
	start := time.Now()
	e.logger.Warn("add_internal_place: executing operator-signed job (the internal data place, `16` §9)")
	out, stderr, err := e.runner.Run(ctx, InternalPlaceHelper, "create", "0")
	line := strings.TrimSpace(string(out))
	if err != nil {
		return fmt.Errorf("add_internal_place: helper refused: %v: %s", err, strings.TrimSpace(string(stderr)))
	}
	if strings.HasPrefix(line, "skipped ") {
		// Not an error the operator can retry away: the pool has no room by the ruled rule. Fail the job with the
		// helper's own numbers so the hub shows why.
		return fmt.Errorf("add_internal_place: %s", line)
	}
	m := reHelperResult.FindStringSubmatch(line)
	if m == nil {
		return fmt.Errorf("add_internal_place: unexpected helper output %q", line)
	}
	gib, _ := strconv.Atoi(m[3])
	rec := localapi.InternalPlaceRecord{FSUUID: m[2], GiB: gib, MadeBy: "signed-job", MadeAt: time.Now().UTC().Format(time.RFC3339)}
	if err := localapi.WriteInternalPlace(e.recordFile, rec); err != nil {
		return fmt.Errorf("add_internal_place: writing the record: %w", err)
	}
	if e.ensure != nil {
		e.ensure(ctx)
	}
	e.logger.Warn("add_internal_place: complete", "result", m[1], "fs_uuid", m[2], "gib", gib,
		"duration_ms", time.Since(start).Milliseconds())
	return nil
}