package web

import (
	"net/http"
	"time"

	"gitea.mynodes.xyz/ilker/llmgw/internal/store"
)

// ChatModel is one entry in the chat page's model picker.
type ChatModel struct {
	Name string
	// Simulated marks a model that returns synthetic text rather than
	// inference output. The picker says so, because the two are
	// indistinguishable from the outside until the reply arrives.
	Simulated bool
	// OnDemand marks a model with nothing running that loads when asked. It is
	// offered anyway: the first message is what asks, so hiding it until it
	// runs meant it could never be started from here.
	OnDemand bool
	// Hardware is what the model's running replicas compute on: "cpu", or a
	// GPU class. Several when it runs on both, and empty when nothing runs
	// or nothing said.
	Hardware []string
}

// Runs names the hardware for the picker: "GPU", "CPU", or "GPU + CPU" for a
// model with replicas on both, where which one answers is the router's choice
// and each reply says which it was.
func (m ChatModel) Runs() string {
	var gpu, cpu bool
	for _, h := range m.Hardware {
		if h == "cpu" {
			cpu = true
		} else {
			gpu = true
		}
	}
	switch {
	case gpu && cpu:
		return "GPU + CPU"
	case gpu:
		return "GPU"
	case cpu:
		return "CPU"
	}
	return ""
}

// ChatContext is one thing the chat page can spend against: a project, or the
// person themselves.
type ChatContext struct {
	Value string
	Label string
}

type chatData struct {
	Nav      Nav
	Contexts []ChatContext
	Context  string
	User     store.User
	Models   []ChatModel
	CSRF     string
	Version  string
	Now      string
}

// Chat renders the in-browser chat for one signed-in person.
func Chat(user store.User, models []ChatModel, contexts []ChatContext, current, version string) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		noStore(w)
		render(w, "chat", chatData{
			Nav:      navFrom(r, "chat"),
			Contexts: contexts, Context: current,
			User: user, Models: models, CSRF: csrfFor(r),
			Version: version, Now: time.Now().UTC().Format(time.RFC3339),
		})
	}
}

// Guard runs a handler only for a signed-in, approved account.
//
// Exported because the chat lives in the router — it needs the endpoint
// registry and the request path — while the session machinery lives here. The
// alternative was a second copy of the session check next to the one thing that
// must never have two copies.
//
// Its POSTs carry the CSRF token in a header rather than a form field, because
// they are JSON. A header is a stronger check than a field: a cross-site form
// post cannot set one at all.
func (p *AccountPages) Guard(
	next func(w http.ResponseWriter, r *http.Request, user store.User),
) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		noStore(w)
		sess, user, ok := p.session(r)
		if !ok {
			if r.Method == http.MethodGet {
				http.Redirect(w, r, "/login", http.StatusSeeOther)
			} else {
				http.Error(w, "not signed in", http.StatusUnauthorized)
			}
			return
		}
		if r.Method != http.MethodGet {
			token := r.Header.Get("X-CSRF-Token")
			if token == "" {
				token = r.FormValue("csrf")
			}
			if !p.accounts.CheckCSRF(sess, token) {
				http.Error(w, "bad request", http.StatusBadRequest)
				return
			}
		}
		next(w, p.withNav(r, user), user)
	}
}