import type { Kysely } from "kysely";
import type { Migration } from "kysely/migration";

/**
 * Column kinds: `t` text, `i` integer, `r` real, `fk:<table>` text reference. Not null by default;
 * a trailing `?` makes it nullable. Only portable types, so the same code runs on SQLite and Postgres.
 */
type Kind = string;
type Spec = Array<[name: string, kind: Kind]>;

async function create(
  db: Kysely<any>,
  name: string,
  cols: Spec,
  opts: { unique?: string[][]; indexes?: string[][] } = {},
): Promise<void> {
  let b = db.schema.createTable(name).addColumn("id", "text", (c) => c.primaryKey());
  const fkCols: string[] = [];
  for (const [col, kind] of cols) {
    const nullable = kind.endsWith("?");
    const base = nullable ? kind.slice(0, -1) : kind;
    const isFk = base.startsWith("fk:");
    const type = base === "i" ? "integer" : base === "r" ? "real" : "text";
    if (isFk) fkCols.push(col);
    b = b.addColumn(col, type, (c) => {
      let x = c;
      if (isFk) x = x.references(`${base.slice(3)}.id`);
      return nullable ? x : x.notNull();
    });
  }
  for (const u of opts.unique ?? []) b = b.addUniqueConstraint(`${name}_${u.join("_")}_uq`, u as Array<"id">);
  await b.execute();

  const indexes = [...fkCols.map((c) => [c]), ...(opts.indexes ?? [])];
  for (const cols of indexes) {
    await db.schema
      .createIndex(`${name}_${cols.join("_")}_idx`)
      .on(name)
      .columns(cols as Array<"id">)
      .execute();
  }
}

export const initial: Migration = {
  async up(db: Kysely<any>) {
    await create(
      db,
      "users",
      [
        ["username", "t"],
        ["display_name", "t"],
        ["password_hash", "t"],
        ["role", "t"],
        ["preferences", "t"],
        ["created_at", "t"],
        ["updated_at", "t"],
      ],
      { unique: [["username"]] },
    );
    await create(
      db,
      "sessions",
      [
        ["user_id", "fk:users"],
        ["token_hash", "t"],
        ["expires_at", "t"],
        ["created_at", "t"],
      ],
      { unique: [["token_hash"]] },
    );
    await create(
      db,
      "invites",
      [
        ["code_hash", "t"],
        ["created_by", "fk:users"],
        ["used_by", "fk:users?"],
        ["expires_at", "t"],
        ["created_at", "t"],
      ],
      { unique: [["code_hash"]] },
    );
    await create(
      db,
      "app_tokens",
      [
        ["user_id", "fk:users"],
        ["name", "t"],
        ["token_hash", "t"],
        ["scopes", "t"],
        ["last_used_at", "t?"],
        ["revoked_at", "t?"],
        ["created_at", "t"],
      ],
      { unique: [["token_hash"]] },
    );
    // works.parent_id is a self reference; works.cover_attachment_id and merged_into_id stay
    // plain columns (attachments is created later; merges may point at any work).
    await create(
      db,
      "works",
      [
        ["media_type", "t"],
        ["title", "t"],
        ["original_title", "t"],
        ["year", "i?"],
        ["release_date", "t?"],
        ["creators", "t"],
        ["description", "t"],
        ["cover_url", "t"],
        ["cover_attachment_id", "t?"],
        ["metadata", "t"],
        ["parent_id", "fk:works?"],
        ["position", "t?"],
        ["owner_user_id", "fk:users?"],
        ["merged_into_id", "t?"],
        ["created_at", "t"],
        ["updated_at", "t"],
      ],
      { indexes: [["merged_into_id"], ["media_type"]] },
    );
    await create(
      db,
      "external_ids",
      [
        ["work_id", "fk:works"],
        ["namespace", "t"],
        ["value", "t"],
      ],
      { unique: [["namespace", "value"]] },
    );
    await create(
      db,
      "work_aliases",
      [
        ["user_id", "fk:users"],
        ["from_work_id", "fk:works"],
        ["to_work_id", "fk:works"],
      ],
      { unique: [["user_id", "from_work_id"]] },
    );
    await create(db, "work_history", [
      ["work_id", "fk:works"],
      ["before", "t"],
      ["after", "t"],
      ["actor", "t"],
      ["created_at", "t"],
    ]);
    await create(
      db,
      "entries",
      [
        ["user_id", "fk:users"],
        ["work_id", "fk:works"],
        ["status", "t"],
        ["rating", "i?"],
        ["review", "t?"],
        ["private_notes", "t?"],
        ["favorite", "i"],
        ["tags", "t"],
        ["custom_fields", "t"],
        ["visibility", "t"],
        ["overrides", "t"],
        ["media_type_override", "t?"],
        ["field_sources", "t"],
        ["created_at", "t"],
        ["updated_at", "t"],
        ["deleted_at", "t?"],
      ],
      { unique: [["user_id", "work_id"]] },
    );
    await create(db, "engagements", [
      ["entry_id", "fk:entries"],
      ["started_at", "t?"],
      ["started_precision", "t"],
      ["finished_at", "t?"],
      ["finished_precision", "t"],
      ["progress", "t"],
      ["platform", "t?"],
      ["rating", "i?"],
      ["notes", "t?"],
      ["custom_fields", "t"],
      ["field_sources", "t"],
      ["created_at", "t"],
      ["updated_at", "t"],
      ["deleted_at", "t?"],
    ]);
    await create(
      db,
      "source_connections",
      [
        ["user_id", "fk:users"],
        ["plugin_id", "t"],
        ["name", "t"],
        ["config", "t"],
        ["credentials_enc", "t?"],
        ["schedule_minutes", "i?"],
        ["cursor", "t?"],
        ["status", "t"],
        ["last_run_at", "t?"],
        ["created_at", "t"],
      ],
    );
    await create(
      db,
      "engagement_sources",
      [
        ["engagement_id", "fk:engagements"],
        ["connection_id", "fk:source_connections"],
        ["record_key", "t"],
      ],
      { unique: [["connection_id", "record_key"]] },
    );
    await create(
      db,
      "listens",
      [
        ["user_id", "fk:users"],
        ["listened_at", "t"],
        ["artist", "t"],
        ["track", "t"],
        ["album", "t?"],
        ["duration_ms", "i?"],
        ["mbids", "t"],
        ["work_id", "fk:works?"],
        ["source", "t"],
        ["source_key", "t"],
        ["created_at", "t"],
      ],
      { unique: [["user_id", "source", "source_key"]], indexes: [["user_id", "listened_at"]] },
    );
    await create(db, "lists", [
      ["user_id", "fk:users"],
      ["name", "t"],
      ["description", "t"],
      ["kind", "t"],
      ["visibility", "t"],
      ["rating", "i?"],
      ["review", "t?"],
      ["created_at", "t"],
      ["updated_at", "t"],
      ["deleted_at", "t?"],
    ]);
    await create(db, "list_items", [
      ["list_id", "fk:lists"],
      ["work_id", "fk:works"],
      ["position", "i"],
      ["note", "t?"],
    ]);
    await create(db, "custom_field_definitions", [
      ["user_id", "fk:users"],
      ["name", "t"],
      ["type", "t"],
      ["options", "t"],
      ["applies_to", "t"],
      ["level", "t"],
      ["created_at", "t"],
    ]);
    await create(db, "copies", [
      ["user_id", "fk:users"],
      ["work_id", "fk:works?"],
      ["title_hint", "t?"],
      ["format", "t?"],
      ["acquired_from", "t?"],
      ["acquired_at", "t?"],
      ["acquired_precision", "t"],
      ["price_cents", "i?"],
      ["currency", "t?"],
      ["notes", "t?"],
      ["custom_fields", "t"],
      ["source_ref", "t?"],
      ["created_at", "t"],
      ["updated_at", "t"],
      ["deleted_at", "t?"],
    ]);
    await create(
      db,
      "attachments",
      [
        ["user_id", "fk:users"],
        ["sha256", "t"],
        ["mime", "t"],
        ["size", "i"],
        ["filename", "t"],
        ["caption", "t?"],
        ["taken_at", "t?"],
        ["visibility", "t?"],
        ["created_at", "t"],
      ],
      { indexes: [["sha256"]] },
    );
    await create(
      db,
      "attachment_links",
      [
        ["attachment_id", "fk:attachments"],
        ["entity", "t"],
        ["entity_id", "t"],
      ],
      { indexes: [["entity", "entity_id"]] },
    );
    await create(
      db,
      "user_history",
      [
        ["user_id", "fk:users"],
        ["entity", "t"],
        ["entity_id", "t"],
        ["before", "t"],
        ["after", "t"],
        ["actor", "t"],
        ["created_at", "t"],
      ],
      { indexes: [["entity", "entity_id"]] },
    );
    await create(db, "match_suggestions", [
      ["user_id", "fk:users"],
      ["work_id", "fk:works"],
      ["candidate_work_id", "fk:works"],
      ["score", "r"],
      ["status", "t"],
      ["created_at", "t"],
    ]);
    await create(db, "source_runs", [
      ["connection_id", "fk:source_connections"],
      ["mode", "t"],
      ["started_at", "t"],
      ["finished_at", "t?"],
      ["status", "t"],
      ["counts", "t"],
      ["log", "t"],
      ["error", "t?"],
    ]);
    await create(
      db,
      "source_records",
      [
        ["connection_id", "fk:source_connections"],
        ["key", "t"],
        ["kind", "t"],
        ["current_hash", "t"],
        ["first_seen", "t"],
        ["last_seen", "t"],
        ["deleted_at", "t?"],
        ["merged_into_key", "t?"],
        ["target_entity", "t?"],
        ["target_id", "t?"],
      ],
      { unique: [["connection_id", "key"]], indexes: [["target_entity", "target_id"]] },
    );
    await create(db, "source_record_versions", [
      ["record_id", "fk:source_records"],
      ["hash", "t"],
      ["raw_gz", "t"],
      ["seen_at", "t"],
    ]);
    await create(
      db,
      "change_events",
      [
        ["user_id", "fk:users"],
        ["connection_id", "fk:source_connections?"],
        ["run_id", "fk:source_runs?"],
        ["record_id", "fk:source_records?"],
        ["type", "t"],
        ["target_entity", "t"],
        ["target_id", "t?"],
        ["payload", "t"],
        ["status", "t"],
        ["created_at", "t"],
        ["resolved_at", "t?"],
      ],
      { indexes: [["user_id", "status"]] },
    );
    await create(
      db,
      "jobs",
      [
        ["type", "t"],
        ["payload", "t"],
        ["run_at", "t"],
        ["status", "t"],
        ["attempts", "i"],
        ["last_error", "t?"],
        ["locked_at", "t?"],
        ["lock_key", "t?"],
        ["created_at", "t"],
      ],
      { indexes: [["status", "run_at"], ["lock_key"]] },
    );
  },

  async down(db: Kysely<any>) {
    for (const table of [
      "jobs",
      "change_events",
      "source_record_versions",
      "source_records",
      "source_runs",
      "match_suggestions",
      "user_history",
      "attachment_links",
      "attachments",
      "copies",
      "custom_field_definitions",
      "list_items",
      "lists",
      "listens",
      "engagement_sources",
      "source_connections",
      "engagements",
      "entries",
      "work_history",
      "work_aliases",
      "external_ids",
      "works",
      "app_tokens",
      "invites",
      "sessions",
      "users",
    ]) {
      await db.schema.dropTable(table).execute();
    }
  },
};