import { ensureS3SdkLoaded, makeS3Client } from "../storage/s3-client.js";
import { multipartUpload } from "../storage/s3-multipart.js";
import { buildR2Key, computeStorageContentHash } from "../r2.js";
import {
  buildS3ObjectUrl,
  getCorsOrigins,
  prepareS3Connection,
  validateS3Connection,
} from "./s3Service.js";
import { userLogger } from "../utils/logger.js";
import {
  buildStoragePointerValue,
  buildStoragePrefixFromKey,
} from "../utils/storagePointer.js";
import {
  getVideoNoteErrorMessage,
  normalizeVideoNotePayload,
  VIDEO_NOTE_ERROR_CODES,
} from "./videoNotePayload.js";
import { calculateTorrentInfoHash } from "../utils/torrentHash.js";
import {
  isLikelyCorsError,
  buildGenericCorsGuidance,
} from "../utils/uploadErrorHints.js";

const STATUS_VARIANTS = new Set(["info", "success", "error", "warning"]);
const INFO_HASH_PATTERN = /^[a-f0-9]{40}$/;

// A storageService.getConnection() result keeps bucket/region/endpoint/forcePathStyle
// under `.meta`; validateS3Connection reads them at the top level. Flatten so a saved
// connection (e.g. Backblaze B2) can be uploaded to without "S3 endpoint is required".
function flattenS3Settings(raw = {}) {
  const meta = raw && typeof raw.meta === "object" && raw.meta ? raw.meta : {};
  const pickBool = (a, b) =>
    typeof a === "boolean" ? a : typeof b === "boolean" ? b : false;
  return {
    ...raw,
    endpoint: raw.endpoint || meta.endpoint || "",
    bucket: raw.bucket || meta.bucket || "",
    region: raw.region || meta.region || "auto",
    accessKeyId: raw.accessKeyId || "",
    secretAccessKey: raw.secretAccessKey || "",
    forcePathStyle: pickBool(raw.forcePathStyle, meta.forcePathStyle),
    publicBaseUrl:
      raw.publicBaseUrl ||
      meta.publicBaseUrl ||
      raw.baseDomain ||
      meta.baseDomain ||
      "",
  };
}

function normalizeInfoHash(value) {
  return typeof value === "string" ? value.trim().toLowerCase() : "";
}

function isValidInfoHash(value) {
  return INFO_HASH_PATTERN.test(value);
}

const defaultDeps = {
  ensureS3SdkLoaded,
  makeS3Client,
  multipartUpload,
  buildR2Key,
  computeStorageContentHash,
  buildS3ObjectUrl,
  getCorsOrigins,
  prepareS3Connection,
  validateS3Connection,
  userLogger,
  buildStoragePointerValue,
  buildStoragePrefixFromKey,
  getVideoNoteErrorMessage,
  normalizeVideoNotePayload,
  calculateTorrentInfoHash,
};

export class S3UploadService {
  constructor(deps = {}) {
    this.deps = { ...defaultDeps, ...deps };
    this.listeners = new Map();
  }

  async _resolveUploadIdentifier({ infoHash = "", file = null } = {}) {
    const normalizedInfoHash = normalizeInfoHash(infoHash);
    if (isValidInfoHash(normalizedInfoHash)) {
      return normalizedInfoHash;
    }
    if (!file) {
      return "";
    }
    try {
      const computedHash = await this.deps.calculateTorrentInfoHash(file);
      const normalizedComputed = normalizeInfoHash(computedHash);
      if (isValidInfoHash(normalizedComputed)) {
        return normalizedComputed;
      }
    } catch (err) {
      this.deps.userLogger.warn(
        "Failed to precompute info hash for storage key:",
        err
      );
    }
    return "";
  }

  on(event, handler) {
    if (typeof handler !== "function") {
      return () => {};
    }
    if (!this.listeners.has(event)) {
      this.listeners.set(event, new Set());
    }
    const handlers = this.listeners.get(event);
    handlers.add(handler);
    return () => {
      handlers.delete(handler);
      if (!handlers.size) {
        this.listeners.delete(event);
      }
    };
  }

  emit(event, detail) {
    const handlers = this.listeners.get(event);
    if (!handlers) {
      return;
    }
    for (const handler of handlers) {
      try {
        handler(detail);
      } catch (err) {
        this.deps.userLogger.error(
          "[s3UploadService] Listener error for",
          event,
          err
        );
      }
    }
  }

  normalizeStatusVariant(variant) {
    if (STATUS_VARIANTS.has(variant)) {
      return variant;
    }
    return "info";
  }

  setUploadStatus(message = "", variant = "info") {
    this.emit("uploadStatus", {
      message: message || "",
      variant: this.normalizeStatusVariant(variant),
    });
  }

  setUploading(isUploading) {
    this.emit("uploadStateChange", { isUploading: Boolean(isUploading) });
  }

  updateProgress(fraction) {
    this.emit("uploadProgress", { fraction });
  }

  async verifyConnection({
    settings = {},
    createBucketIfMissing = true,
    origins = null,
  } = {}) {
    const normalized = this.deps.validateS3Connection(settings);
    const allowedOrigins = Array.isArray(origins)
      ? origins
      : this.deps.getCorsOrigins();
    const prepared = await this.deps.prepareS3Connection({
      ...normalized,
      origins: allowedOrigins,
      createBucketIfMissing,
    });
    return prepared;
  }

  async prepareUpload(settingsOrNpub = {}, options = {}) {
    const { createBucketIfMissing = true, credentials } = options || {};
    // Two call styles must both work:
    //  - direct:        prepareUpload(settings, { createBucketIfMissing })
    //  - mediaUploader: prepareUpload(npub, { credentials })  ← like r2Service
    // When credentials come from storageService.getConnection, the bucket/region/
    // endpoint live under `.meta`, so flatten them to the top level that
    // validateS3Connection reads. (npub is ignored when credentials are supplied.)
    const raw = credentials || settingsOrNpub || {};
    const settings = flattenS3Settings(raw);
    const prepared = await this.verifyConnection({
      settings,
      createBucketIfMissing,
    });
    return {
      settings: prepared,
      bucketEntry: {
        bucket: prepared.bucket,
        publicBaseUrl: prepared.publicBaseUrl,
      },
    };
  }

  async uploadFile({
    file,
    endpoint,
    region,
    accessKeyId,
    secretAccessKey,
    forcePathStyle,
    bucket,
    key,
    onProgress,
    createBucketIfMissing = true,
  } = {}) {
    if (
      !file ||
      !bucket ||
      !key ||
      !endpoint ||
      !accessKeyId ||
      !secretAccessKey
    ) {
      throw new Error("Missing required parameters for uploadFile");
    }

    await this.deps.ensureS3SdkLoaded();

    const s3 = this.deps.makeS3Client({
      endpoint,
      region,
      accessKeyId,
      secretAccessKey,
      forcePathStyle: Boolean(forcePathStyle),
    });

    await this.deps.multipartUpload({
      s3,
      bucket,
      key,
      file,
      contentType: file.type || "application/octet-stream",
      createBucketIfMissing,
      region,
      onProgress: (fraction) => {
        if (typeof onProgress === "function") {
          onProgress(fraction);
        }
      },
    });

    return { bucket, key };
  }

  async uploadVideo({
    npub = "",
    file = null,
    thumbnailFile = null,
    torrentFile = null,
    metadata = {},
    infoHash = "",
    settings = {},
    createBucketIfMissing = true,
    publishVideoNote,
    onReset,
    forcedVideoKey = "",
    forcedVideoUrl = "",
    forcedTorrentKey = "",
    forcedTorrentUrl = "",
  } = {}) {
    if (!npub) {
      this.setUploadStatus("Unable to encode npub.", "error");
      return false;
    }

    const rawTitleCandidate =
      metadata && typeof metadata === "object" ? metadata.title : metadata;
    const title =
      typeof rawTitleCandidate === "string"
        ? rawTitleCandidate.trim()
        : String(rawTitleCandidate ?? "").trim();

    if (!title) {
      this.setUploadStatus(
        this.deps.getVideoNoteErrorMessage(VIDEO_NOTE_ERROR_CODES.MISSING_TITLE),
        "error"
      );
      return false;
    }

    if (!file) {
      this.setUploadStatus("Select a video or HLS file to upload.", "error");
      return false;
    }

    let normalized = null;
    try {
      normalized = this.deps.validateS3Connection(settings);
    } catch (err) {
      this.setUploadStatus(err?.message || "Invalid S3 settings.", "error");
      return false;
    }

    this.setUploading(true);
    this.updateProgress(0);

    try {
      await this.deps.ensureS3SdkLoaded();

      // Computing the torrent info-hash (and the content-hash fallback) reads the
      // ENTIRE file before the upload starts and before any progress is emitted —
      // on multi-GB videos that's a long, silent pause that looks like a freeze.
      const willHashFile =
        Boolean(file) && !isValidInfoHash(normalizeInfoHash(infoHash));
      if (willHashFile) {
        this.setUploadStatus(
          "Analyzing video (large files can take a moment)…",
          "info",
        );
      }

      const keyIdentifier = await this._resolveUploadIdentifier({
        infoHash,
        file,
      });
      const normalizedInfoHash = normalizeInfoHash(infoHash || keyIdentifier);
      const hasValidInfoHash = isValidInfoHash(normalizedInfoHash);
      // When no info-hash is available, derive a content-based namespace so two
      // distinct URL-first uploads that share a filename can't overwrite each
      // other. Kept separate from keyIdentifier so magnet generation still keys
      // off the real info-hash only.
      const storageIdentifier =
        keyIdentifier ||
        (file ? await this.deps.computeStorageContentHash(file) : "");

      const s3 = this.deps.makeS3Client({
        endpoint: normalized.endpoint,
        region: normalized.region,
        accessKeyId: normalized.accessKeyId,
        secretAccessKey: normalized.secretAccessKey,
        forcePathStyle: Boolean(normalized.forcePathStyle),
      });

      const key =
        forcedVideoKey ||
        this.deps.buildR2Key(npub, file, storageIdentifier);
      const publicUrl =
        forcedVideoUrl ||
        this.deps.buildS3ObjectUrl({
          publicBaseUrl: normalized.publicBaseUrl,
          endpoint: normalized.endpoint,
          bucket: normalized.bucket,
          key,
          forcePathStyle: normalized.forcePathStyle,
        });

      let statusMessage = `Uploading to ${normalized.bucket}…`;
      this.setUploadStatus(statusMessage, "info");

      // Track optional-asset failures so the user gets a visible signal instead
      // of a silently-missing thumbnail/torrent (Cloudflare-upload #5).
      let thumbnailFailed = false;
      let torrentFailed = false;

      if (thumbnailFile) {
        this.setUploadStatus("Uploading thumbnail...", "info");
        const thumbExt = thumbnailFile.name.split(".").pop() || "jpg";
        const thumbKey = key.replace(/\.[^/.]+$/, "") + `.thumb.${thumbExt}`;
        try {
          await this.deps.multipartUpload({
            s3,
            bucket: normalized.bucket,
            key: thumbKey,
            file: thumbnailFile,
            contentType: thumbnailFile.type || "image/jpeg",
            createBucketIfMissing,
            region: normalized.region,
          });
          const thumbUrl = this.deps.buildS3ObjectUrl({
            publicBaseUrl: normalized.publicBaseUrl,
            endpoint: normalized.endpoint,
            bucket: normalized.bucket,
            key: thumbKey,
            forcePathStyle: normalized.forcePathStyle,
          });
          if (typeof metadata === "object") {
            metadata.thumbnail = thumbUrl;
          }
        } catch (err) {
          this.deps.userLogger.warn(
            "Thumbnail upload failed, continuing with video...",
            err
          );
          thumbnailFailed = true;
          this.setUploadStatus(
            "Thumbnail upload failed — publishing without it.",
            "warning"
          );
        }
      }

      this.setUploadStatus(statusMessage, "info");

      await this.deps.multipartUpload({
        s3,
        bucket: normalized.bucket,
        key,
        file,
        contentType: file.type || "application/octet-stream",
        createBucketIfMissing,
        region: normalized.region,
        onProgress: (fraction) => {
          this.updateProgress(fraction);
        },
      });

      let torrentUrl = forcedTorrentUrl || "";
      if (torrentFile) {
        this.setUploadStatus("Uploading torrent metadata...", "info");
        const torrentKey =
          forcedTorrentKey ||
          (() => {
            const baseKey = key.replace(/\.[^/.]+$/, "");
            if (baseKey && baseKey !== key) {
              return `${baseKey}.torrent`;
            }
            return `${key}.torrent`;
          })();
        try {
          await this.deps.multipartUpload({
            s3,
            bucket: normalized.bucket,
            key: torrentKey,
            file: torrentFile,
            contentType: "application/x-bittorrent",
            createBucketIfMissing,
            region: normalized.region,
          });
          if (!torrentUrl) {
            torrentUrl = this.deps.buildS3ObjectUrl({
              publicBaseUrl: normalized.publicBaseUrl,
              endpoint: normalized.endpoint,
              bucket: normalized.bucket,
              key: torrentKey,
              forcePathStyle: normalized.forcePathStyle,
            });
          }
        } catch (err) {
          this.deps.userLogger.warn(
            "Torrent metadata upload failed, continuing...",
            err
          );
          torrentFailed = true;
          this.setUploadStatus(
            "Torrent upload failed — publishing URL-first without the .torrent.",
            "warning"
          );
        }
      }

      if (typeof publishVideoNote !== "function") {
        this.deps.userLogger.warn(
          "publishVideoNote handler missing; skipping publish step."
        );
        return false;
      }

      let generatedMagnet = "";
      let generatedWs = "";

      if (hasValidInfoHash) {
        const encodedDn = encodeURIComponent(file.name);
        const encodedWs = encodeURIComponent(publicUrl);
        let magnet = `magnet:?xt=urn:btih:${normalizedInfoHash}&dn=${encodedDn}&ws=${encodedWs}`;
        if (torrentUrl) {
          const encodedXs = encodeURIComponent(torrentUrl);
          magnet += `&xs=${encodedXs}`;
        }
        generatedMagnet = magnet;
        generatedWs = publicUrl;
      } else {
        if (infoHash) {
          this.deps.userLogger.warn(
            "Invalid info hash provided. Skipping magnet generation.",
            infoHash
          );
        }
        this.setUploadStatus(
          "Info hash missing or invalid. Publishing URL-first without WebTorrent fallback.",
          "warning"
        );
      }

      const storagePrefix = this.deps.buildStoragePrefixFromKey({
        publicBaseUrl: normalized.publicBaseUrl,
        key,
      });
      const storagePointer = this.deps.buildStoragePointerValue({
        provider: "s3",
        prefix: storagePrefix,
      });

      const rawVideoPayload = {
        title,
        url: publicUrl,
        magnet: generatedMagnet || (metadata?.magnet ?? ""),
        thumbnail: metadata?.thumbnail ?? "",
        description: metadata?.description ?? "",
        storagePointer,
        ws: generatedWs || (metadata?.ws ?? ""),
        xs: torrentUrl || (metadata?.xs ?? ""),
        infoHash: hasValidInfoHash ? normalizedInfoHash : "",
        enableComments: metadata?.enableComments,
        isNsfw: metadata?.isNsfw,
        isForKids: metadata?.isForKids,
      };

      const { payload, errors } =
        this.deps.normalizeVideoNotePayload(rawVideoPayload);
      if (errors.length) {
        const message = this.deps.getVideoNoteErrorMessage(errors[0]);
        this.setUploadStatus(message, "error");
        return false;
      }

      const published = await publishVideoNote(payload, {
        onSuccess: () => {
          if (typeof onReset === "function") {
            onReset();
          }
        },
      });

      if (published) {
        const caveats = [];
        if (thumbnailFailed) caveats.push("thumbnail");
        if (torrentFailed) caveats.push("torrent");
        const suffix = caveats.length
          ? ` (note: ${caveats.join(" & ")} upload failed)`
          : "";
        this.setUploadStatus(
          `Published ${publicUrl}${suffix}`,
          caveats.length ? "warning" : "success"
        );
      }
      return Boolean(published);
    } catch (err) {
      this.deps.userLogger.error("S3 upload failed:", err);
      let message = err?.message
        ? `Upload failed: ${err.message}`
        : "Upload failed.";
      // A CORS rejection during the browser PUT/POST is an opaque "Failed to
      // fetch" — attach actionable guidance (parity with the R2 path).
      if (isLikelyCorsError(err)) {
        message += ` ${buildGenericCorsGuidance({ endpoint: normalized?.endpoint })}`;
      }
      this.setUploadStatus(message, "error");
      return false;
    } finally {
      this.setUploading(false);
      this.updateProgress(Number.NaN);
    }
  }
}

const s3UploadService = new S3UploadService();

export default s3UploadService;