package httpapi

import (
	"encoding/json"
	"net/http"
	"strings"

	"evobgp/internal/jobs"
	"evobgp/internal/observability"
	"evobgp/internal/store"
)

func (s *Server) registerMaintenanceRoutes(m *http.ServeMux) {
	m.HandleFunc("GET /maintenance/policies", s.handleListMaintenancePolicies)
	m.HandleFunc("POST /maintenance/policies", s.handleCreateMaintenancePolicy)
	m.HandleFunc("GET /maintenance/policies/{id}", s.handleGetMaintenancePolicy)
	m.HandleFunc("PATCH /maintenance/policies/{id}", s.handlePatchMaintenancePolicy)
	m.HandleFunc("DELETE /maintenance/policies/{id}", s.handleDeleteMaintenancePolicy)
	m.HandleFunc("GET /maintenance/policies/{id}/hints", s.handleMaintenancePolicyHints)
	m.HandleFunc("GET /maintenance/config-audit", s.handleListMaintenanceConfigAudit)
	m.HandleFunc("POST /maintenance/run", s.handleMaintenanceRun)
	m.HandleFunc("POST /maintenance/dry-run", s.handleMaintenanceDryRun)
}

func maintenancePolicyJSON(p *store.MaintenancePolicy) map[string]any {
	if p == nil {
		return map[string]any{}
	}
	out := map[string]any{
		"id":              p.ID,
		"name":            p.Name,
		"table_name":      p.TableName,
		"condition":       p.Condition,
		"vacuum_strategy": p.VacuumStrategy,
		"schedule":        p.Schedule,
		"enabled":         p.Enabled,
		"dry_run_enabled": p.DryRunEnabled,
	}
	if p.RetentionPeriodSec != nil {
		out["retention_period_sec"] = *p.RetentionPeriodSec
	}
	if p.MaxRows != nil {
		out["max_rows"] = *p.MaxRows
	}
	if p.LastRunAt != nil {
		out["last_run_at"] = p.LastRunAt.UTC().Format("2006-01-02T15:04:05Z")
	}
	if p.LastStatus != "" {
		out["last_status"] = p.LastStatus
	}
	if p.LastError != "" {
		out["last_error"] = p.LastError
	}
	if !p.CreatedAt.IsZero() {
		out["created_at"] = p.CreatedAt.UTC().Format("2006-01-02T15:04:05Z")
	}
	if !p.UpdatedAt.IsZero() {
		out["updated_at"] = p.UpdatedAt.UTC().Format("2006-01-02T15:04:05Z")
	}
	return out
}

func (s *Server) handleListMaintenancePolicies(w http.ResponseWriter, r *http.Request) {
	a, ok := authFromContext(r.Context())
	if !ok || !s.requirePerm(w, a, "bgp:monitoring:read") || !s.requirePostgres(w) {
		return
	}
	cursor := r.URL.Query().Get("cursor")
	limit := parseLimitQuery(r, 20, 100)
	items, next, hasMore, err := s.store.ListMaintenancePolicies(cursor, limit)
	if err != nil {
		writeInternalError(w, "maintenance_policies_list", err)
		return
	}
	out := make([]map[string]any, 0, len(items))
	for _, p := range items {
		out = append(out, maintenancePolicyJSON(p))
	}
	writeJSON(w, http.StatusOK, map[string]any{"items": out, "next_cursor": next, "has_more": hasMore})
}

func (s *Server) handleGetMaintenancePolicy(w http.ResponseWriter, r *http.Request) {
	a, ok := authFromContext(r.Context())
	if !ok || !s.requirePerm(w, a, "bgp:monitoring:read") || !s.requirePostgres(w) {
		return
	}
	p, err := s.store.GetMaintenancePolicy(r.PathValue("id"))
	if err != nil {
		writeStoreErr(w, err)
		return
	}
	writeJSON(w, http.StatusOK, maintenancePolicyJSON(p))
}

func (s *Server) handleCreateMaintenancePolicy(w http.ResponseWriter, r *http.Request) {
	a, ok := authFromContext(r.Context())
	if !ok || !s.requirePostgres(w) || !s.requireOperatorStrict(w, a) {
		return
	}
	var body store.MaintenancePolicy
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		writeProblem(w, http.StatusBadRequest, "Bad Request", invalidInputDetail)
		return
	}
	p, err := s.store.CreateMaintenancePolicy(&body)
	if err != nil {
		writeStoreErr(w, err)
		return
	}
	_ = s.store.AppendMaintenancePolicyConfigAudit(actorPrefix(a), p.ID, "create", nil, maintenancePolicyJSON(p))
	observability.IncMaintenanceConfigChange("create")
	s.reloadMaintenanceConfig(r)
	writeJSON(w, http.StatusCreated, maintenancePolicyJSON(p))
}

func (s *Server) handlePatchMaintenancePolicy(w http.ResponseWriter, r *http.Request) {
	a, ok := authFromContext(r.Context())
	if !ok || !s.requirePostgres(w) || !s.requireOperatorStrict(w, a) {
		return
	}
	id := r.PathValue("id")
	before, err := s.store.GetMaintenancePolicy(id)
	if err != nil {
		writeStoreErr(w, err)
		return
	}
	var patch store.MaintenancePolicyPatch
	if err := json.NewDecoder(r.Body).Decode(&patch); err != nil {
		writeProblem(w, http.StatusBadRequest, "Bad Request", invalidInputDetail)
		return
	}
	updated, err := s.store.UpdateMaintenancePolicy(id, &patch)
	if err != nil {
		writeStoreErr(w, err)
		return
	}
	_ = s.store.AppendMaintenancePolicyConfigAudit(actorPrefix(a), id, "update", maintenancePolicyJSON(before), maintenancePolicyJSON(updated))
	observability.IncMaintenanceConfigChange("update")
	s.reloadMaintenanceConfig(r)
	writeJSON(w, http.StatusOK, maintenancePolicyJSON(updated))
}

func (s *Server) handleDeleteMaintenancePolicy(w http.ResponseWriter, r *http.Request) {
	a, ok := authFromContext(r.Context())
	if !ok || !s.requirePostgres(w) || !s.requireOperatorStrict(w, a) {
		return
	}
	id := r.PathValue("id")
	before, err := s.store.GetMaintenancePolicy(id)
	if err != nil {
		writeStoreErr(w, err)
		return
	}
	if err := s.store.DeleteMaintenancePolicy(id); err != nil {
		writeStoreErr(w, err)
		return
	}
	_ = s.store.AppendMaintenancePolicyConfigAudit(actorPrefix(a), id, "delete", maintenancePolicyJSON(before), nil)
	observability.IncMaintenanceConfigChange("delete")
	s.reloadMaintenanceConfig(r)
	w.WriteHeader(http.StatusNoContent)
}

func (s *Server) handleMaintenancePolicyHints(w http.ResponseWriter, r *http.Request) {
	a, ok := authFromContext(r.Context())
	if !ok || !s.requirePerm(w, a, "bgp:monitoring:read") || !s.requirePostgres(w) {
		return
	}
	if s.maintStats == nil {
		writeProblem(w, http.StatusServiceUnavailable, "Unavailable", "postgresql backend required")
		return
	}
	p, err := s.store.GetMaintenancePolicy(r.PathValue("id"))
	if err != nil {
		writeStoreErr(w, err)
		return
	}
	hints, err := s.maintStats.Hints(r.Context(), p.TableName)
	if err != nil {
		writeInternalError(w, "maintenance_policy_hints", err)
		return
	}
	writeJSON(w, http.StatusOK, hints)
}

func (s *Server) handleListMaintenanceConfigAudit(w http.ResponseWriter, r *http.Request) {
	a, ok := authFromContext(r.Context())
	if !ok || !s.requirePerm(w, a, "bgp:monitoring:read") || !s.requirePostgres(w) {
		return
	}
	cursor := r.URL.Query().Get("cursor")
	limit := parseLimitQuery(r, 20, 100)
	items, next, hasMore, err := s.store.ListMaintenancePolicyConfigAudit(cursor, limit)
	if err != nil {
		writeInternalError(w, "maintenance_config_audit", err)
		return
	}
	out := make([]map[string]any, 0, len(items))
	for _, row := range items {
		out = append(out, map[string]any{
			"id":           row.ID,
			"policy_id":    row.PolicyID,
			"actor_prefix": row.ActorPrefix,
			"action":       row.Action,
			"before":       row.Before,
			"after":        row.After,
			"created_at":   row.CreatedAt.UTC().Format("2006-01-02T15:04:05Z"),
		})
	}
	writeJSON(w, http.StatusOK, map[string]any{"items": out, "next_cursor": next, "has_more": hasMore})
}

type maintenanceRunBody struct {
	PolicyID string `json:"policy_id"`
}

func (s *Server) handleMaintenanceRun(w http.ResponseWriter, r *http.Request) {
	s.enqueueMaintenancePolicy(w, r, false)
}

func (s *Server) handleMaintenanceDryRun(w http.ResponseWriter, r *http.Request) {
	s.enqueueMaintenancePolicy(w, r, true)
}

func (s *Server) enqueueMaintenancePolicy(w http.ResponseWriter, r *http.Request, dryRun bool) {
	a, ok := authFromContext(r.Context())
	if !ok || !s.requirePostgres(w) || !s.requireOperatorStrict(w, a) {
		return
	}
	var body maintenanceRunBody
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		writeProblem(w, http.StatusBadRequest, "Bad Request", invalidInputDetail)
		return
	}
	policyID := strings.TrimSpace(body.PolicyID)
	if policyID == "" {
		writeProblem(w, http.StatusBadRequest, "Bad Request", "policy_id is required")
		return
	}
	if _, err := s.store.GetMaintenancePolicy(policyID); err != nil {
		writeStoreErr(w, err)
		return
	}
	kind := "maintenance_policy_run"
	if !s.checkPgMaintRateLimit(a.TenantID, kind+":"+policyID) {
		writeProblem(w, http.StatusTooManyRequests, "Too Many Requests", "wait before repeating this maintenance operation")
		return
	}
	idem := strings.TrimSpace(r.Header.Get("Idempotency-Key"))
	var idemPtr *string
	if idem != "" {
		idemPtr = &idem
	}
	title := "Maintenance policy run"
	if dryRun {
		title = "Maintenance policy dry-run"
	}
	j, _, err := s.jobs.Enqueue(a.TenantID, jobs.KindMaintenancePolicyRun, idemPtr, nil, map[string]any{
		"policy_id": policyID, "dry_run": dryRun, "actor_prefix": actorPrefix(a), "job_title": title,
	})
	if err != nil {
		writeInternalError(w, "maintenance_policy_enqueue", err)
		return
	}
	w.Header().Set("Location", "/v1/jobs/"+j.ID)
	snap := j.Snapshot()
	writeJSON(w, http.StatusAccepted, map[string]any{"job_id": snap["job_id"], "status": snap["status"]})
}

func (s *Server) reloadMaintenanceConfig(r *http.Request) {
	if s.maintConfig != nil {
		_ = s.maintConfig.Reload(r.Context())
	}
}