package session

import (
	"encoding/json"
	"os"
	"path/filepath"
	"strings"
	"time"
)

// Stream is a streamd-ready description of one playable channel, as produced by
// a provider catalog lookup. MPD holds the manifest URL whatever its type.
type Stream struct {
	Name         string   `json:"name"`
	Title        string   `json:"title"`
	App          string   `json:"app"`
	Channel      string   `json:"channel"`
	MPD          string   `json:"mpd"`
	Key          string   `json:"key"`
	Keys         []string `json:"keys,omitempty"`
	PSSH         string   `json:"pssh,omitempty"`
	PrimaryKID   string   `json:"primary_kid,omitempty"`
	HeadersJSON  string   `json:"headers_json"`
	Rewriter     string   `json:"rewriter"`
	LicenseURL   string   `json:"license_url,omitempty"`
	AccountID    string   `json:"account_id,omitempty"`
	VideoID      string   `json:"video_id,omitempty"`
	PlaybackURL  string   `json:"playback_url,omitempty"`
	ManifestType string   `json:"manifest_type,omitempty"`
}

// WriteStream writes outputs/<app>/<stamp>/{session.json,mpd.txt,license.txt,…}
// and refreshes outputs/<app>/latest. The app name comes from the caller so no
// provider name is baked in here.
func WriteStream(root, app string, info Stream) (string, error) {
	stamp := time.Now().Format("20060102-150405")
	dir := filepath.Join(root, "outputs", app, stamp)
	if err := os.MkdirAll(dir, 0o755); err != nil {
		return "", err
	}
	raw, err := json.MarshalIndent(info, "", "  ")
	if err != nil {
		return "", err
	}
	if err := os.WriteFile(filepath.Join(dir, "session.json"), append(raw, '\n'), 0o644); err != nil {
		return "", err
	}
	write := func(name, val string) {
		if val == "" {
			return
		}
		_ = os.WriteFile(filepath.Join(dir, name), []byte(val+"\n"), 0o644)
	}
	write("mpd.txt", info.MPD)
	write("license.txt", info.LicenseURL)
	write("pssh.txt", info.PSSH)
	write("key.txt", info.Key)
	write("pid.txt", info.VideoID)
	if len(info.Keys) > 0 {
		write("keys.txt", strings.Join(info.Keys, "\n"))
	}
	latest := filepath.Join(root, "outputs", app, "latest")
	_ = os.RemoveAll(latest)
	_ = copyDir(dir, latest)
	return dir, nil
}