package adminapi

import (
	"context"
	"encoding/json"
	"errors"
	"net/http"
	"time"

	"gitea.mynodes.xyz/ilker/llmgw/internal/control/catalog"
)

// PresetsView is the models that come with llmgw, and whether the leader adds
// them by itself.
type PresetsView struct {
	// Auto is whether a preset is added when a node fits it and the catalog
	// has no model that makes what it makes (presets.auto).
	Auto    bool         `json:"auto"`
	Presets []PresetView `json:"presets"`
}

// PresetView is one preset as it stands in this cluster.
type PresetView struct {
	Name        string          `json:"name"`
	Makes       string          `json:"makes"`
	Description string          `json:"description"`
	Card        string          `json:"card"`
	Licence     catalog.License `json:"licence"`
	// Fits is whether some node has a card that meets the preset's need;
	// FitsClasses names those classes.
	Fits        bool     `json:"fits"`
	FitsClasses []string `json:"fits_classes,omitempty"`
	InCatalog   bool     `json:"in_catalog"`
	// AddedBy is "auto" when the leader added it, who did otherwise, ""
	// when it was not added as a preset; AddedAt is when.
	AddedBy string    `json:"added_by,omitempty"`
	AddedAt time.Time `json:"added_at,omitzero"`
	// Declined is whether somebody removed it after it was added, so it is
	// not added again by itself; adding it again clears that.
	Declined bool `json:"declined"`
}

// PresetsAutoRequest turns the automatic adding of presets on or off.
type PresetsAutoRequest struct {
	On bool `json:"on"`
}

// errPresetsUnavailable is a control plane without the store presets are
// kept in.
var errPresetsUnavailable = errors.New("this control plane has no store, so presets cannot be added here")

// Presets is the presets as they stand in this cluster.
func (a *API) Presets(ctx context.Context) (PresetsView, error) {
	return PresetsView{}, errPresetsUnavailable
}

// AddPreset adds the preset of that name, and clears its decline.
func (a *API) AddPreset(ctx context.Context, name, by string) error {
	return errPresetsUnavailable
}

// SetAutoPresets turns presets.auto on or off.
func (a *API) SetAutoPresets(ctx context.Context, on bool, by string) error {
	return errPresetsUnavailable
}

func (a *API) registerPresets(mux Mux) {
	mux.HandleFunc("GET /api/v1/presets", func(w http.ResponseWriter, r *http.Request) {
		v, err := a.Presets(r.Context())
		if err != nil {
			writeError(w, presetStatus(err), err.Error())
			return
		}
		writeJSON(w, http.StatusOK, v)
	})
	mux.HandleFunc("POST /api/v1/presets/{name}", func(w http.ResponseWriter, r *http.Request) {
		if err := a.AddPreset(r.Context(), r.PathValue("name"), actorOf(r)); err != nil {
			writeError(w, presetStatus(err), err.Error())
			return
		}
		writeJSON(w, http.StatusOK, ModelAdded{Added: r.PathValue("name")})
	})
	mux.HandleFunc("PUT /api/v1/presets/auto", func(w http.ResponseWriter, r *http.Request) {
		var req PresetsAutoRequest
		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
			writeError(w, http.StatusBadRequest, err.Error())
			return
		}
		if err := a.SetAutoPresets(r.Context(), req.On, actorOf(r)); err != nil {
			writeError(w, presetStatus(err), err.Error())
			return
		}
		v, err := a.Presets(r.Context())
		if err != nil {
			writeError(w, presetStatus(err), err.Error())
			return
		}
		writeJSON(w, http.StatusOK, v)
	})
}

// errNoSuchPreset is a name no preset has.
var errNoSuchPreset = errors.New("no preset of that name")

func presetStatus(err error) int {
	switch {
	case errors.Is(err, errPresetsUnavailable):
		return http.StatusNotImplemented
	case errors.Is(err, errNoSuchPreset):
		return http.StatusNotFound
	default:
		return http.StatusBadRequest
	}
}