package server

import (
	"context"
	"net/http"
	"net/url"
	"strings"

	"music-server/internal/backend"

	"github.com/danielgtaylor/huma/v2"
	"github.com/google/uuid"
)

// UploadRequest is the body of POST /soundtracks/uploads.
type UploadRequest struct {
	Name string `json:"name" minLength:"1" maxLength:"200" doc:"Name of the new soundtrack, also its folder name in the music folder"`
}

type startUploadInput struct {
	Body UploadRequest
}

type uploadIDInput struct {
	ID string `path:"id" format:"uuid" doc:"ID of the upload, from POST /soundtracks/uploads"`
}

func (in *uploadIDInput) id() uuid.UUID {
	return uuid.MustParse(in.ID)
}

type uploadFileInput struct {
	ID      string `path:"id" format:"uuid" doc:"ID of the upload, from POST /soundtracks/uploads"`
	File    string `path:"file" doc:"File name of the song, e.g. \"01 Title.mp3\". Plain names only: put songs from disc folders in one folder, e.g. \"1-01 Title.mp3\"."`
	RawBody []byte `contentType:"audio/mpeg" doc:"The MP3 file"`
}

type createdUpload struct {
	Status int
	Body   backend.Upload
}

func (s *Server) registerUploads(a huma.API) {
	u := s.uploads
	op := func(id, method, path, summary, description string, errs ...int) route {
		return route{
			op: huma.Operation{
				OperationID: id,
				Method:      method,
				Path:        path,
				Summary:     summary,
				Description: description,
				Tags:        []string{"uploads"},
				Errors:      errs,
			},
			// Uploads and syncs never run at the same time.
			locked: true,
		}
	}

	start := op("start-upload", http.MethodPost, "/soundtracks/uploads", "Start uploading a soundtrack",
		"Starts adding a new soundtrack. Send its songs with PUT /soundtracks/uploads/{id}/files/{file}, then "+
			"POST /soundtracks/uploads/{id}/finish. The name must be usable as a folder name, and no soundtrack, "+
			"folder or other upload may have it, ignoring case. Unfinished uploads are removed after a day.",
		http.StatusBadRequest, http.StatusConflict, http.StatusServiceUnavailable)
	start.op.DefaultStatus = http.StatusCreated
	register(s, a, start, func(ctx context.Context, in *startUploadInput) (*createdUpload, error) {
		upload, err := u.Start(ctx, in.Body.Name)
		if err != nil {
			return nil, apiError(err)
		}
		return &createdUpload{Status: http.StatusCreated, Body: upload}, nil
	})

	register(s, a, op("get-upload", http.MethodGet, "/soundtracks/uploads/{id}", "Get an upload",
		"Returns an unfinished upload with the songs received so far, for example to resume it.", http.StatusNotFound),
		func(ctx context.Context, in *uploadIDInput) (*jsonBody[backend.Upload], error) {
			return ok(u.Get(in.id()))
		})

	file := op("upload-song", http.MethodPut, "/soundtracks/uploads/{id}/files/{file}", "Upload a song",
		"Stores one song of the upload, replacing a song of the same name, so a failed song can be sent again. "+
			"Only MP3 files are accepted. The size limits are set on the server with UPLOAD_MAX_FILE_MB and UPLOAD_MAX_TOTAL_MB.",
		http.StatusBadRequest, http.StatusNotFound, http.StatusRequestEntityTooLarge)
	file.op.MaxBodyBytes = s.cfg.UploadMaxFileSize
	register(s, a, file, func(ctx context.Context, in *uploadFileInput) (*jsonBody[backend.UploadFile], error) {
		id, err := uuid.Parse(in.ID)
		if err != nil {
			return nil, huma.Error422UnprocessableEntity("invalid upload ID")
		}
		// With an encoded slash (%2F) in the path, Echo leaves the file name encoded.
		if decoded, err := url.PathUnescape(in.File); err == nil && strings.ContainsAny(decoded, `/\`) {
			return nil, huma.Error400BadRequest("plain file names only: put songs from disc folders in one folder, e.g. \"1-01 Title.mp3\"")
		}
		return ok(u.PutFile(id, in.File, in.RawBody))
	})

	register(s, a, op("finish-upload", http.MethodPost, "/soundtracks/uploads/{id}/finish", "Finish an upload",
		"Moves the songs into a new folder in the music folder, adds the soundtrack to the library and returns it. "+
			"Refused when a soundtrack with the same songs exists.",
		http.StatusBadRequest, http.StatusNotFound, http.StatusConflict),
		func(ctx context.Context, in *uploadIDInput) (*jsonBody[backend.SoundtrackWithSongList], error) {
			soundtrack, err := u.Finish(ctx, in.id())
			if err != nil {
				return nil, apiError(err)
			}
			s.soundtracksChanged(ctx)
			return ok(soundtrack, nil)
		})

	cancel := op("cancel-upload", http.MethodDelete, "/soundtracks/uploads/{id}", "Cancel an upload",
		"Deletes an unfinished upload and its songs.", http.StatusNotFound)
	cancel.op.DefaultStatus = http.StatusNoContent
	register(s, a, cancel, func(ctx context.Context, in *uploadIDInput) (*struct{}, error) {
		if err := u.Cancel(in.id()); err != nil {
			return nil, apiError(err)
		}
		return nil, nil
	})
}