package server

import (
	"net/http"
	"strings"

	"jarl/internal/auth"
	"jarl/internal/engine"
	"jarl/internal/model"
)

// zoneCompare: GET /zones/{zone}/compare lines up a zone's records across
// the views that have it (docs/views.md#linked-zones). ?views=a,b picks the
// views (default: every view with a primary zone of that name), ?all=1
// includes the names and types that are the same everywhere.
func (s *Server) zoneCompare(w http.ResponseWriter, r *http.Request, p *auth.Principal) error {
	st, err := s.state(r)
	if err != nil {
		return err
	}
	z, err := s.zoneByPath(r, st, p)
	if err != nil {
		// A name in several views is what there is to compare.
		ref := r.PathValue("zone")
		if ref == "root" {
			ref = "."
		}
		name, perr := engine.ParseZoneName(ref)
		if zs := st.ZonesNamed(name); perr != nil || len(zs) < 2 {
			return err
		} else {
			z = zs[0]
		}
	}
	var want []string
	for _, v := range strings.Split(r.URL.Query().Get("views"), ",") {
		if v = strings.TrimSpace(v); v != "" {
			want = append(want, v)
		}
	}
	var zones []*model.Zone
	for _, o := range st.ZonesNamed(z.Name) {
		vn := st.ViewName(o)
		if o.Type != model.ZonePrimary || !p.CanSeeZone(o.Name, vn) || !p.Can(auth.Action{Resource: auth.ResRecords, Zone: o.Name, View: vn}) {
			continue
		}
		if len(want) > 0 && !containsFold(want, vn) {
			continue
		}
		zones = append(zones, o)
	}
	st.SortByView(zones)
	if len(zones) < 2 {
		return badRequest("zone %s is in only one view (that you may read): there is nothing to compare", engine.Display(z.Name))
	}
	rows := engine.CompareZones(st, zones)
	all := queryBool(r, "all")
	out := struct {
		Zone   string              `json:"zone"`
		Views  []string            `json:"views"`
		Linked bool                `json:"linked"` // all of them in one link
		Same   int                 `json:"same"`   // names and types the same everywhere
		Rows   []engine.CompareRow `json:"rows"`
	}{Zone: engine.Display(z.Name), Rows: []engine.CompareRow{}, Linked: true}
	for _, o := range zones {
		out.Views = append(out.Views, st.ViewName(o))
		out.Linked = out.Linked && o.LinkGroup != 0 && o.LinkGroup == zones[0].LinkGroup
	}
	for _, row := range rows {
		if row.Same {
			out.Same++
			if !all {
				continue
			}
		}
		out.Rows = append(out.Rows, row)
	}
	writeJSON(w, http.StatusOK, out)
	return nil
}

func containsFold(list []string, s string) bool {
	for _, x := range list {
		if strings.EqualFold(x, s) {
			return true
		}
	}
	return false
}