package api

import (
	"fmt"
	"net/http"
	"strings"
	"time"

	cfgstore "github.com/datarhei/core/v16/config/store"
	"github.com/datarhei/core/v16/whip"

	"github.com/labstack/echo/v4"
)

// WHIPHandler provides HTTP API access to the WHIP server channel information.
type WHIPHandler struct {
	whip   whip.Server
	config cfgstore.Store
}

// NewWHIP returns a new WHIPHandler backed by the provided WHIP server.
func NewWHIP(whip whip.Server, config cfgstore.Store) *WHIPHandler {
	return &WHIPHandler{
		whip:   whip,
		config: config,
	}
}

// WHIPChannel represents a currently active WHIP publish session.
type WHIPChannel struct {
	// Name is the stream identifier used in the WHIP URL path.
	Name string `json:"name" jsonschema:"minLength=1"`
	// PublishedAt is the RFC 3339 timestamp when the publisher connected.
	PublishedAt time.Time `json:"published_at"`
}

// WHIPURLs holds the publish URL (for OBS) and the internal SDP relay URL (for FFmpeg).
type WHIPURLs struct {
	// PublishURL is the URL to enter in OBS → Settings → Stream → Server.
	// Format: http://<public_host>:<port>/whip/<stream_key>
	PublishURL string `json:"publish_url"`
	// SDPURL is the internal FFmpeg-readable relay URL.
	// Format: http://localhost:<port>/whip/<stream_key>/sdp
	SDPURL string `json:"sdp_url"`
	// StreamKey is the key component used in both URLs.
	StreamKey string `json:"stream_key"`
}

// whipPublicBase returns "http://<host>:<port>" derived from the active config.
func (h *WHIPHandler) whipPublicBase() (string, string, error) {
	if h.config == nil {
		return "", "", fmt.Errorf("config not available")
	}
	cfg := h.config.GetActive()
	addr := cfg.WHIP.Address // e.g. ":8555" or "0.0.0.0:8555"

	// Extract port from address.
	port := addr
	if idx := strings.LastIndex(addr, ":"); idx >= 0 {
		port = addr[idx+1:]
	}

	// Pick public host.
	host := "localhost"
	if len(cfg.Host.Name) > 0 && cfg.Host.Name[0] != "" {
		host = cfg.Host.Name[0]
	}

	return fmt.Sprintf("http://%s:%s", host, port),
		fmt.Sprintf("http://localhost:%s", port),
		nil
}

// GetURL returns the WHIP publish URL for a given stream key.
// @Summary Get WHIP publish URL for a stream key
// @Description Returns the URL to configure in OBS and the internal SDP relay URL for FFmpeg.
// @Tags v16.?.?
// @ID whip-3-get-url
// @Produce json
// @Param name path string true "Stream key"
// @Success 200 {object} WHIPURLs
// @Security ApiKeyAuth
// @Router /api/v3/whip/{name}/url [get]
func (h *WHIPHandler) GetURL(c echo.Context) error {
	name := c.Param("name")
	if name == "" {
		return c.JSON(http.StatusBadRequest, map[string]string{"error": "stream key is required"})
	}

	publicBase, localBase, err := h.whipPublicBase()
	if err != nil {
		return c.JSON(http.StatusServiceUnavailable, map[string]string{"error": err.Error()})
	}

	return c.JSON(http.StatusOK, WHIPURLs{
		PublishURL: fmt.Sprintf("%s/whip/%s", publicBase, name),
		SDPURL:     fmt.Sprintf("%s/whip/%s/sdp", localBase, name),
		StreamKey:  name,
	})
}

// GetServerURL returns the base WHIP server URL (without a stream key).
// @Summary Get WHIP server base URL
// @Description Returns the base publish URL and configuration so the UI can display it in a WHIP Server panel.
// @Tags v16.?.?
// @ID whip-3-get-server-url
// @Produce json
// @Success 200 {object} WHIPServerInfo
// @Security ApiKeyAuth
// @Router /api/v3/whip/url [get]
func (h *WHIPHandler) GetServerURL(c echo.Context) error {
	publicBase, localBase, err := h.whipPublicBase()
	if err != nil {
		return c.JSON(http.StatusServiceUnavailable, map[string]string{"error": err.Error()})
	}

	var token string
	if h.config != nil {
		token = h.config.GetActive().WHIP.Token
	}

	return c.JSON(http.StatusOK, WHIPServerInfo{
		BasePublishURL: fmt.Sprintf("%s/whip/", publicBase),
		BaseSDPURL:     fmt.Sprintf("%s/whip/", localBase),
		HasToken:       token != "",
		ExampleOBS: fmt.Sprintf("%s/whip/<stream-key>", publicBase),
		InputAddressTemplate: "{whip:name=<stream-key>}",
	})
}

// WHIPServerInfo holds the base URLs and metadata shown in the WHIP Server panel.
type WHIPServerInfo struct {
	// BasePublishURL is the base URL for OBS. Append the stream key.
	BasePublishURL string `json:"base_publish_url"`
	// BaseSDPURL is the base internal SDP relay URL.
	BaseSDPURL string `json:"base_sdp_url"`
	// HasToken indicates whether a bearer token is required.
	HasToken bool `json:"has_token"`
	// ExampleOBS shows an example URL with placeholder stream key.
	ExampleOBS string `json:"example_obs_url"`
	// InputAddressTemplate is the process input address template for WHIP.
	InputAddressTemplate string `json:"input_address_template"`
}

// ListChannels lists all currently active WHIP publishers.
// @Summary List all publishing WHIP streams
// @Description List all currently active WHIP (WebRTC HTTP Ingestion Protocol) streams.
// @Tags v16.?.?
// @ID whip-3-list-channels
// @Produce json
// @Success 200 {array} WHIPChannel
// @Security ApiKeyAuth
// @Router /api/v3/whip [get]
func (h *WHIPHandler) ListChannels(c echo.Context) error {
	channels := h.whip.Channels()

	list := make([]WHIPChannel, 0, len(channels.Publisher))
	for name, since := range channels.Publisher {
		list = append(list, WHIPChannel{
			Name:        name,
			PublishedAt: since,
		})
	}

	return c.JSON(http.StatusOK, list)
}