package httpapi

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

	"evobgp/internal/pipeline"
)

func (s *Server) resolveRevisionRetentionMinutesQuery(r *http.Request, tenantID string) (minutes int, ok bool) {
	if raw := r.URL.Query().Get("retention_minutes"); raw != "" {
		n, err := strconv.Atoi(raw)
		if err != nil {
			return 0, false
		}
		if n < pipeline.RevisionMinTTLMin || n > pipeline.RevisionMaxTTLMin {
			return 0, false
		}
		return n, true
	}
	return s.defaultRevisionRetentionMinutes(tenantID)
}

func (s *Server) defaultRevisionRetentionMinutes(tenantID string) (int, bool) {
	settings, err := s.store.ListGlobalSettings(tenantID)
	if err != nil {
		return pipeline.ClampRevisionRetentionMinutes(0), true
	}
	return pipeline.ClampRevisionRetentionMinutes(pipeline.RevisionRetentionMinutesFromSettings(settings)), true
}

func (s *Server) resolveRevisionRetentionMinutesBody(r *http.Request, tenantID string) (minutes int, ok bool) {
	var body struct {
		RetentionMinutes *int `json:"retention_minutes"`
	}
	if r.Body != nil && r.ContentLength != 0 {
		if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
			return 0, false
		}
		if body.RetentionMinutes != nil {
			m := *body.RetentionMinutes
			if m < pipeline.RevisionMinTTLMin || m > pipeline.RevisionMaxTTLMin {
				return 0, false
			}
			return m, true
		}
	}
	return s.defaultRevisionRetentionMinutes(tenantID)
}

func (s *Server) handleRevisionPruneEstimate(w http.ResponseWriter, r *http.Request) {
	a, ok := authFromContext(r.Context())
	if !ok || !s.requirePerm(w, a, "bgp:operations:read") {
		return
	}
	minutes, valid := s.resolveRevisionRetentionMinutesQuery(r, a.TenantID)
	if !valid {
		writeProblem(w, http.StatusUnprocessableEntity, "Unprocessable Entity", "retention_minutes must be an integer in range 15..43200")
		return
	}
	cutoff := pipeline.RevisionCutoffFromMinutes(minutes)
	est, err := s.store.EstimateRevisionPrune(a.TenantID, cutoff, minutes)
	if err != nil {
		writeInternalError(w, "revision prune estimate", err)
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{
		"retention_minutes":     est.RetentionMinutes,
		"cutoff_at":             est.CutoffAt.UTC().Format(time.RFC3339Nano),
		"revision_count":        est.RevisionCount,
		"prefix_row_count":      est.PrefixRowCount,
		"orphan_snapshot_count": est.OrphanSnapshotCount,
		"bytes_estimate":        est.BytesEstimate,
	})
}

func (s *Server) handleRevisionPrune(w http.ResponseWriter, r *http.Request) {
	a, ok := authFromContext(r.Context())
	if !ok || !s.requirePerm(w, a, "bgp:operations:admin") {
		return
	}
	minutes, valid := s.resolveRevisionRetentionMinutesBody(r, a.TenantID)
	if !valid {
		writeProblem(w, http.StatusUnprocessableEntity, "Unprocessable Entity", "retention_minutes must be an integer in range 15..43200")
		return
	}
	cutoff := pipeline.RevisionCutoffFromMinutes(minutes)
	res, err := s.store.PruneRevisionsWithStats(a.TenantID, cutoff)
	if err != nil {
		writeInternalError(w, "revision prune", err)
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{
		"deleted_revisions":        res.DeletedRevisions,
		"deleted_prefix_snapshots": res.DeletedPrefixSnapshots,
		"deleted_prefix_rows":      res.DeletedPrefixRows,
		"bytes_estimate":           res.BytesEstimate,
	})
}