package containerapi

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

	"github.com/itworx/pulse/internal/auth"
	"github.com/itworx/pulse/internal/container"
	"github.com/itworx/pulse/internal/problem"
)

type Handler struct {
	Provider interface {
		Snapshot(context.Context) (container.Snapshot, error)
	}
	Limits container.Limits
}

func (h Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet || (r.URL.Path != "/api/v1/containers" && !strings.HasPrefix(r.URL.Path, "/api/v1/containers/")) {
		http.NotFound(w, r)
		return
	}
	if _, ok := auth.PrincipalFromContext(r.Context()); !ok {
		problem.Write(w, r, http.StatusUnauthorized, "UNAUTHORIZED", "Authentication required", "Authentication is required to read containers.", nil)
		return
	}
	snapshot, err := h.snapshot(r)
	if err != nil {
		if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
			return
		}
		problem.Write(w, r, http.StatusServiceUnavailable, "CONTAINERS_UNAVAILABLE", "Containers not available", "Containergegevens konden niet worden gelezen.", nil)
		return
	}
	if r.URL.Path != "/api/v1/containers" {
		id := strings.TrimPrefix(r.URL.Path, "/api/v1/containers/")
		for _, item := range snapshot.Containers {
			if item.ID == id {
				writeJSON(w, struct {
					Source    container.Source    `json:"source"`
					Container container.Container `json:"container"`
				}{Source: snapshot.Source, Container: item})
				return
			}
		}
		http.NotFound(w, r)
		return
	}
	limit := 50
	if value := r.URL.Query().Get("limit"); value != "" {
		parsed, parseErr := strconv.Atoi(value)
		if parseErr != nil {
			problem.Write(w, r, http.StatusBadRequest, "CONTAINER_QUERY_INVALID", "Invalid container query", "De containerlimiet is ongeldig.", nil)
			return
		}
		limit = parsed
	}
	order := r.URL.Query().Get("sort")
	if order == "" {
		order = "name"
	}
	page, err := container.FilteredPage(snapshot, limit, r.URL.Query().Get("after"), h.Limits, r.URL.Query().Get("q"), r.URL.Query().Get("state"), r.URL.Query().Get("health"), order)
	if err != nil {
		problem.Write(w, r, http.StatusBadRequest, "CONTAINER_QUERY_INVALID", "Invalid container query", "De containerlimiet of cursor is ongeldig.", nil)
		return
	}
	writeJSON(w, page)
}
func (h Handler) snapshot(r *http.Request) (container.Snapshot, error) {
	if h.Provider == nil {
		return container.UnknownSnapshot(time.Now().UTC(), "container", "agent", "source_unavailable"), nil
	}
	return h.Provider.Snapshot(r.Context())
}
func writeJSON(w http.ResponseWriter, value any) {
	w.Header().Set("Content-Type", "application/json")
	w.Header().Set("Cache-Control", "private, max-age=5")
	_ = json.NewEncoder(w).Encode(value)
}