package monitor

import (
	"encoding/json"
	"log"
	"sync"

	"gitea.dooplex.hu/admin/felhom-hub/internal/store"
)

// HostOOBChecker raises an operator WARNING when a host's OOB access path is DEGRADED — felhom-sshd
// down (while the operator peer is configured, i.e. OOB is meant to work) OR its config is invalid.
// It answers "can the operator get into this box right now, and if not, why" proactively, from the
// hub. Transition-based (ok↔degraded, one event per transition — the HostCapabilityChecker shape), so
// a persistent problem alerts ONCE, not every 60s sweep, and a recovery is noted.
//
// A host with no oob stanza (pre-H1 / feature off) is never evaluated. A degraded state requires the
// operator peer to be configured — a box where OOB was never set up is not "broken".
type HostOOBChecker struct {
	store   *store.Store
	logger  *log.Logger
	onEvent EventNotifyFunc

	mu         sync.Mutex
	degraded   map[string]bool // hostID → currently-degraded
	customerOf map[string]string
}

// NewHostOOBChecker seeds per-host degraded state from the latest reports WITHOUT alerting (a problem
// present at startup alerts on the first transition-in evaluated after seed = never re-alerts a
// steady bad state; matches HostCapabilityChecker). Actually seeds silent, then Check transitions.
func NewHostOOBChecker(s *store.Store, onEvent EventNotifyFunc, logger *log.Logger) *HostOOBChecker {
	c := &HostOOBChecker{
		store:      s,
		logger:     logger,
		onEvent:    onEvent,
		degraded:   make(map[string]bool),
		customerOf: make(map[string]string),
	}
	rows, err := s.GetHostOOBStates()
	if err != nil {
		logger.Printf("[WARN] Host OOB checker: failed to seed: %v", err)
		return c
	}
	seeded := 0
	for _, row := range rows {
		if s.IsCustomerBlocked(row.CustomerID) || !row.Present {
			continue
		}
		c.customerOf[row.HostID] = row.CustomerID
		if oobDegraded(row) {
			c.degraded[row.HostID] = true // seed the bad state so we don't re-alert it on cycle 1
			seeded++
		}
	}
	logger.Printf("[INFO] Host OOB checker initialized: %d host(s) seeded degraded", seeded)
	return c
}

// oobDegraded is the degraded predicate: config invalid, OR (OOB meant to work — operator peer
// configured — AND felhom-sshd is not active/reachable).
func oobDegraded(r store.HostOOBRow) bool {
	if !r.Present {
		return false
	}
	if r.ConfigInvalid {
		return true
	}
	if r.OperatorPeerConfigured && (!r.FelhomSshdActive || !r.Reachable) {
		return true
	}
	return false
}

// Check evaluates all hosts and emits oob_degraded / oob_recovered on transitions.
func (c *HostOOBChecker) Check() {
	rows, err := c.store.GetHostOOBStates()
	if err != nil {
		c.logger.Printf("[WARN] Host OOB check failed: %v", err)
		return
	}
	c.mu.Lock()
	defer c.mu.Unlock()

	seen := make(map[string]bool, len(rows))
	for _, row := range rows {
		if c.store.IsCustomerBlocked(row.CustomerID) {
			delete(c.degraded, row.HostID)
			continue
		}
		if !row.Present {
			continue // no oob stanza → not evaluated
		}
		seen[row.HostID] = true
		c.customerOf[row.HostID] = row.CustomerID
		bad := oobDegraded(row)
		was := c.degraded[row.HostID]
		switch {
		case bad && !was:
			c.degraded[row.HostID] = true
			c.emit(row, "oob_degraded", "warning")
		case !bad && was:
			delete(c.degraded, row.HostID)
			c.emit(row, "oob_recovered", "info")
		}
	}
	for id := range c.degraded {
		if !seen[id] {
			delete(c.degraded, id)
		}
	}
}

// IsDegraded reports the current tracked state for a host (test/UI helper).
func (c *HostOOBChecker) IsDegraded(hostID string) bool {
	c.mu.Lock()
	defer c.mu.Unlock()
	return c.degraded[hostID]
}

func (c *HostOOBChecker) emit(row store.HostOOBRow, eventType, severity string) {
	var msg string
	if eventType == "oob_degraded" {
		reason := "felhom-sshd unreachable"
		if row.ConfigInvalid {
			reason = "felhom-sshd config invalid (sshd -t fails)"
		}
		msg = "Host " + row.HostID + ": OPERATOR ACCESS DEGRADED — " + reason +
			". The break-glass net (auto-heal + vaulted root@pam console) is still under the box."
	} else {
		msg = "Host " + row.HostID + ": operator access recovered (felhom-sshd reachable again)."
	}
	details, _ := json.Marshal(map[string]any{
		"host_id":          row.HostID,
		"felhom_sshd_port": row.FelhomSshdPort,
		"active":           row.FelhomSshdActive,
		"reachable":        row.Reachable,
		"config_invalid":   row.ConfigInvalid,
	})
	c.logger.Printf("[%s] Host OOB: %s (%s)", map[string]string{"warning": "WARN", "info": "INFO"}[severity], row.HostID, eventType)
	if _, err := c.store.SaveEvent(row.CustomerID, eventType, severity, msg, string(details), "hub"); err != nil {
		c.logger.Printf("[WARN] save %s for %s: %v", eventType, row.HostID, err)
		return
	}
	if c.onEvent != nil {
		c.onEvent(row.CustomerID, eventType, severity, msg, string(details), "hub")
	}
}