import Database from "better-sqlite3";
import type { VehicleClass } from "@parking/shared";

// One table. Each row is one booth decision: what the camera saw, what the operator
// chose, and (once reviewed) what a trusted person says the vehicle is. The crop itself
// lives on disk beside the DB (crops/<booth>/<item>.jpg) so the trainer on the same host
// reads it straight off the volume.

export interface ItemRow {
  id: string;
  booth: string;
  /** "wash" = a desk decision (operator fields set); "entry" = a sampled entry read (pure
   *  training material: crop + the camera's class, operator fields empty). */
  kind: "wash" | "entry";
  orderRef: string;
  at: string;
  operatorRef: string;
  operatorCategoryId: string;
  operatorCategoryName: string;
  /** The vision classes the operator's category covers at that site (its mapping) — what
   *  lets a reviewer's CLASS be compared with an operator's CATEGORY. JSON array. */
  operatorClasses: string;
  service: string;
  visionClass: string;
  visionConfidence: number;
  visionCategoryId: string | null;
  downgraded: number;
  imageWidth: number;
  imageHeight: number;
  plateBlurred: number;
  imagePath: string;
  receivedAt: string;
  reviewLabel: string | null; // a VehicleClass, or "unusable"
  reviewedAt: string | null;
  reviewer: string | null;
}

export type ReviewVerdict = VehicleClass | "unusable";

export class CollectorDb {
  readonly #db: Database.Database;

  constructor(file: string) {
    this.#db = new Database(file);
    this.#db.pragma("journal_mode = WAL");
    this.#db.exec(`
      CREATE TABLE IF NOT EXISTS items (
        id TEXT PRIMARY KEY,
        booth TEXT NOT NULL,
        kind TEXT NOT NULL DEFAULT 'wash',
        order_ref TEXT NOT NULL,
        at TEXT NOT NULL,
        operator_ref TEXT NOT NULL DEFAULT '',
        operator_category_id TEXT NOT NULL DEFAULT '',
        operator_category_name TEXT NOT NULL DEFAULT '',
        operator_classes TEXT NOT NULL DEFAULT '[]',
        service TEXT NOT NULL,
        vision_class TEXT NOT NULL,
        vision_confidence REAL NOT NULL,
        vision_category_id TEXT,
        downgraded INTEGER NOT NULL DEFAULT 0,
        image_width INTEGER NOT NULL,
        image_height INTEGER NOT NULL,
        plate_blurred INTEGER NOT NULL,
        image_path TEXT NOT NULL,
        received_at TEXT NOT NULL,
        review_label TEXT,
        reviewed_at TEXT,
        reviewer TEXT
      );
      CREATE INDEX IF NOT EXISTS items_pending ON items (reviewed_at, received_at);
      CREATE INDEX IF NOT EXISTS items_booth ON items (booth, received_at);
    `);
    this.#migrate();
  }

  /** Columns added after the first deploy, with the DDL that adds them to an EXISTING
   *  table. `CREATE TABLE IF NOT EXISTS` above only shapes a NEW database; a volume that
   *  was created by an earlier build keeps its old columns, and every query naming a new
   *  one then fails ("no such column: kind" — art-docker-station, 2026-09-16: the
   *  collector's /health, every ingest, and the trainer's readiness all broke on a DB
   *  from before `kind`). Each entry must be addable to a populated table, i.e. nullable
   *  or carrying a DEFAULT. Append here whenever a column joins the CREATE above. */
  static readonly #ADDED_COLUMNS: ReadonlyArray<readonly [name: string, ddl: string]> = [
    ["kind", "TEXT NOT NULL DEFAULT 'wash'"],
    ["operator_ref", "TEXT NOT NULL DEFAULT ''"],
    ["operator_category_id", "TEXT NOT NULL DEFAULT ''"],
    ["operator_category_name", "TEXT NOT NULL DEFAULT ''"],
    ["operator_classes", "TEXT NOT NULL DEFAULT '[]'"],
    ["vision_category_id", "TEXT"],
    ["downgraded", "INTEGER NOT NULL DEFAULT 0"],
  ];

  /** Bring an existing `items` table up to the current column set (idempotent). */
  #migrate(): void {
    const present = new Set(
      (this.#db.prepare("PRAGMA table_info(items)").all() as { name: string }[]).map((c) => c.name),
    );
    for (const [name, ddl] of CollectorDb.#ADDED_COLUMNS) {
      if (!present.has(name)) this.#db.exec(`ALTER TABLE items ADD COLUMN ${name} ${ddl}`);
    }
  }

  /** The current column names of `items` (for tests and diagnostics). */
  columns(): string[] {
    return (this.#db.prepare("PRAGMA table_info(items)").all() as { name: string }[]).map((c) => c.name);
  }

  close(): void {
    this.#db.close();
  }

  static #map(r: Record<string, unknown>): ItemRow {
    return {
      id: r.id as string,
      booth: r.booth as string,
      kind: r.kind === "entry" ? "entry" : "wash",
      orderRef: r.order_ref as string,
      at: r.at as string,
      operatorRef: r.operator_ref as string,
      operatorCategoryId: r.operator_category_id as string,
      operatorCategoryName: r.operator_category_name as string,
      operatorClasses: r.operator_classes as string,
      service: r.service as string,
      visionClass: r.vision_class as string,
      visionConfidence: r.vision_confidence as number,
      visionCategoryId: (r.vision_category_id as string | null) ?? null,
      downgraded: r.downgraded as number,
      imageWidth: r.image_width as number,
      imageHeight: r.image_height as number,
      plateBlurred: r.plate_blurred as number,
      imagePath: r.image_path as string,
      receivedAt: r.received_at as string,
      reviewLabel: (r.review_label as string | null) ?? null,
      reviewedAt: (r.reviewed_at as string | null) ?? null,
      reviewer: (r.reviewer as string | null) ?? null,
    };
  }

  get(id: string): ItemRow | null {
    const r = this.#db.prepare("SELECT * FROM items WHERE id = ?").get(id) as Record<string, unknown> | undefined;
    return r ? CollectorDb.#map(r) : null;
  }

  insert(row: Omit<ItemRow, "reviewLabel" | "reviewedAt" | "reviewer">): void {
    this.#db
      .prepare(
        `INSERT INTO items (id, booth, kind, order_ref, at, operator_ref, operator_category_id, operator_category_name,
           operator_classes, service, vision_class, vision_confidence, vision_category_id, downgraded,
           image_width, image_height, plate_blurred, image_path, received_at)
         VALUES (@id, @booth, @kind, @orderRef, @at, @operatorRef, @operatorCategoryId, @operatorCategoryName,
           @operatorClasses, @service, @visionClass, @visionConfidence, @visionCategoryId, @downgraded,
           @imageWidth, @imageHeight, @plateBlurred, @imagePath, @receivedAt)`,
      )
      .run(row);
  }

  list(status: "pending" | "reviewed", limit: number, booth?: string): ItemRow[] {
    const where = [status === "pending" ? "reviewed_at IS NULL" : "reviewed_at IS NOT NULL"];
    const params: unknown[] = [];
    if (booth) {
      where.push("booth = ?");
      params.push(booth);
    }
    const order = status === "pending" ? "received_at ASC" : "reviewed_at DESC";
    const rows = this.#db
      .prepare(`SELECT * FROM items WHERE ${where.join(" AND ")} ORDER BY ${order} LIMIT ?`)
      .all(...params, limit) as Record<string, unknown>[];
    return rows.map((r) => CollectorDb.#map(r));
  }

  review(id: string, label: ReviewVerdict, reviewer: string): ItemRow | null {
    this.#db
      .prepare("UPDATE items SET review_label = ?, reviewed_at = ?, reviewer = ? WHERE id = ?")
      .run(label, new Date().toISOString(), reviewer, id);
    return this.get(id);
  }

  /** Per booth: received / pending / reviewed. Per operator (booth + hash): how often the
   *  reviewer's class fell inside the operator's chosen category (agree) or outside
   *  (disagree) — the honest-mistake / fraud rate the outbox exists for. */
  stats(): {
    booths: { booth: string; received: number; pending: number; reviewed: number; entries: number }[];
    operators: { booth: string; operatorRef: string; reviewed: number; agree: number; disagree: number; unusable: number }[];
  } {
    const booths = this.#db
      .prepare(
        `SELECT booth, COUNT(*) AS received,
                SUM(CASE WHEN reviewed_at IS NULL THEN 1 ELSE 0 END) AS pending,
                SUM(CASE WHEN reviewed_at IS NOT NULL THEN 1 ELSE 0 END) AS reviewed,
                SUM(CASE WHEN kind = 'entry' THEN 1 ELSE 0 END) AS entries
         FROM items GROUP BY booth ORDER BY booth`,
      )
      .all() as { booth: string; received: number; pending: number; reviewed: number; entries: number }[];
    // Operator agreement is a WASH thing — an entry sample has no operator decision.
    const reviewed = this.#db
      .prepare("SELECT booth, operator_ref, operator_classes, review_label FROM items WHERE reviewed_at IS NOT NULL AND kind = 'wash'")
      .all() as { booth: string; operator_ref: string; operator_classes: string; review_label: string }[];
    const ops = new Map<string, { booth: string; operatorRef: string; reviewed: number; agree: number; disagree: number; unusable: number }>();
    for (const r of reviewed) {
      const key = `${r.booth} ${r.operator_ref}`;
      let o = ops.get(key);
      if (!o) ops.set(key, (o = { booth: r.booth, operatorRef: r.operator_ref, reviewed: 0, agree: 0, disagree: 0, unusable: 0 }));
      o.reviewed += 1;
      if (r.review_label === "unusable") o.unusable += 1;
      else if ((JSON.parse(r.operator_classes) as string[]).includes(r.review_label)) o.agree += 1;
      else o.disagree += 1;
    }
    return { booths, operators: [...ops.values()].sort((a, b) => b.disagree - a.disagree) };
  }

  /** Reviewed, usable rows — the training set. */
  labelled(): ItemRow[] {
    const rows = this.#db
      .prepare("SELECT * FROM items WHERE reviewed_at IS NOT NULL AND review_label != 'unusable' ORDER BY reviewed_at")
      .all() as Record<string, unknown>[];
    return rows.map((r) => CollectorDb.#map(r));
  }
}