package videochat

import (
	"context"
	"encoding/json"

	"encore.dev/beta/auth"
	"encore.dev/beta/errs"
	"github.com/livekit/protocol/livekit"
)

// OpenRoom returns an existing broadcast or provisions an enabled personal setup.
// The owner comes exclusively from administrator-managed settings, never the caller.
//
//encore:api auth method=POST path=/videochat/rooms/:roomName/open
func OpenRoom(ctx context.Context, roomName string) (*Room, error) {
	if _, ok := auth.UserID(); !ok {
		return nil, &errs.Error{Code: errs.Unauthenticated, Message: "must be logged in"}
	}
	if err := validateRoomName(roomName); err != nil {
		return nil, err
	}
	client, _, err := liveKitClient()
	if err != nil {
		return nil, err
	}
	ctx, cancel := context.WithTimeout(ctx, apiTimeout)
	defer cancel()

	// Serialize lookup and creation across application instances for this name.
	tx, err := profilesDB.Begin(ctx)
	if err != nil {
		return nil, errs.WrapCode(err, errs.Internal, "failed to open room")
	}
	defer tx.Rollback()
	if _, err := tx.Exec(ctx, `SELECT pg_advisory_xact_lock(hashtextextended($1, 0))`, "videochat/open/"+roomName); err != nil {
		return nil, errs.WrapCode(err, errs.Internal, "failed to lock room creation")
	}
	result, err := client.ListRooms(ctx, &livekit.ListRoomsRequest{})
	if err != nil {
		return nil, liveKitError(err)
	}
	for _, room := range result.Rooms {
		if room.Name == roomName {
			metadata, ok := readBroadcast(room)
			if !ok {
				return nil, &errs.Error{Code: errs.FailedPrecondition, Message: "room name is already used by an unmanaged room"}
			}
			_ = logBroadcastSession(ctx, metadata.OwnerID, room.Sid, room.Name, "OPEN")
			return roomResponse(room), nil
		}
	}

	// Multiple enabled owners with the same name are ambiguous: do not pick one.
	rows, err := tx.Query(ctx, `
		SELECT DISTINCT p.user_id::text
		FROM user_profiles p
		LEFT JOIN personal_setup s ON s.user_id = p.user_id
		WHERE (s.can_broadcast = TRUE AND s.room_name = $1)
		   OR (p.member_type = 'broadcaster' AND (
		        s.room_name = $1 
		        OR p.display_name = $1 
		        OR p.user_id::text = $1
		        OR $1 = ('broadcaster-' || SUBSTRING(p.user_id::text, 1, 8))
		        OR $1 = (p.display_name || '-' || SUBSTRING(p.user_id::text, 1, 8))
		   ))
	`, roomName)
	if err != nil {
		return nil, errs.WrapCode(err, errs.Internal, "failed to fetch configured room")
	}
	defer rows.Close()

	var owners []string
	for rows.Next() {
		var o string
		if err := rows.Scan(&o); err != nil {
			return nil, errs.WrapCode(err, errs.Internal, "failed to read configured room owner")
		}
		owners = append(owners, o)
	}
	if err := rows.Err(); err != nil {
		return nil, errs.WrapCode(err, errs.Internal, "failed to fetch configured room")
	}
	if len(owners) == 0 {
		return nil, &errs.Error{Code: errs.NotFound, Message: "no enabled broadcast setup for this room"}
	}
	if len(owners) > 1 {
		return nil, &errs.Error{Code: errs.FailedPrecondition, Message: "room name is configured for more than one owner"}
	}
	owner := owners[0]
	for _, room := range result.Rooms {
		if metadata, ok := readBroadcast(room); ok && metadata.OwnerID == owner && metadata.DisplayName == roomName {
			_ = logBroadcastSession(ctx, metadata.OwnerID, room.Sid, room.Name, "OPEN")
			return roomResponse(room), nil
		}
	}
	metadata, err := json.Marshal(broadcastMetadata{Mode: "broadcast", OwnerID: owner, DisplayName: roomName})
	if err != nil {
		return nil, errs.WrapCode(err, errs.Internal, "failed to encode room metadata")
	}
	room, err := client.CreateRoom(ctx, &livekit.CreateRoomRequest{
		Name:         roomName,
		Metadata:     string(metadata),
		EmptyTimeout: 300,
	})
	if err != nil {
		return nil, liveKitError(err)
	}
	_ = logBroadcastSession(ctx, owner, room.Sid, room.Name, "OPEN")
	return roomResponse(room), nil
}