import { TextDecoder } from 'util';

import * as native from '../sqlite3.pure';
import { EmscriptenType } from '../sqlite3.pure';

const NUMBER = 'number';
const STRING = 'string';
const NULL = 'null';

// change to `true` manually for some debugging
const DEBUG_SQLITE = false;

let cwrap = native.cwrap;

if (DEBUG_SQLITE) {
  cwrap = (name: string, returnType: EmscriptenType, argTypes: EmscriptenType[]) => {
    const exportedFn = native.cwrap(name, returnType, argTypes);

    return (...args: any[]) => {
      console.log(name, ...args);
      return exportedFn(...args);
    };
  };
}

function storeString(string: string) {
  const len = native.lengthBytesUTF8(string);
  const ptr = native._malloc(len + 1);

  native.stringToUTF8(string, ptr, len + 1);

  return { len, ptr };
}

const decoder = new TextDecoder();

function retrieveOutString() {
  const len = native.getValue(native.lengthOutPtr, 'i32');
  const ptr = native.getValue(native.stringOutPtr, 'i32');
  const view = new Uint8Array(native.HEAP8.buffer, ptr, len);

  return decoder.decode(view);
}

export const sqlite3_open_v2: (file: string, mode: number) => number = cwrap('sqlite3_open_v2_x', NUMBER, [
  STRING,
  NUMBER,
]);

export const sqlite3_close_v2: (db: number) => null = cwrap('sqlite3_close_v2_x', NULL, [NUMBER]);

export const sqlite3_close: (db: number) => null = cwrap('sqlite3_close_x', NULL, [NUMBER]);

export const sqlite3_prepare_v2: (db: number, sql: string) => number = cwrap('sqlite3_prepare_v2_x', NUMBER, [
  NUMBER,
  STRING,
]);

export const sqlite3_bind_parameter_index: (stmt: number, sql: string) => number = native.cwrap(
  'sqlite3_bind_parameter_index_x',
  NUMBER,
  [NUMBER, STRING]
);

export const sqlite3_bind_double: (stmt: number, db: number, param: number, value: number) => null = cwrap(
  'sqlite3_bind_double_x',
  NULL,
  [NUMBER, NUMBER, NUMBER, NUMBER]
);

export const sqlite3_bind_int: (stmt: number, db: number, param: number, value: number) => null = cwrap(
  'sqlite3_bind_int_x',
  NULL,
  [NUMBER, NUMBER, NUMBER, NUMBER]
);

const sqlite3_bind_text_x: (stmt: number, db: number, param: number, value: number, len: number) => null = cwrap(
  'sqlite3_bind_text_x',
  NULL,
  [NUMBER, NUMBER, NUMBER, NUMBER, NUMBER]
);

export const sqlite3_bind_text = (stmt: number, db: number, param: number, value: string) => {
  const { len, ptr } = storeString(value);

  try {
    sqlite3_bind_text_x(stmt, db, param, ptr, len);
  } finally {
    native._free(ptr);
  }
};

export const sqlite3_bind_null: (stmt: number, db: number, param: number) => null = cwrap('sqlite3_bind_null_x', NULL, [
  NUMBER,
  NUMBER,
  NUMBER,
]);

export const sqlite3_step: (stmt: number, db: number) => boolean = cwrap('sqlite3_step_x', 'boolean', [NUMBER, NUMBER]);

export const sqlite3_column_count: (stmt: number) => number = cwrap('sqlite3_column_count_x', NUMBER, [NUMBER]);

export const sqlite3_column_type: (stmt: number, index: number) => number = cwrap('sqlite3_column_type_x', NUMBER, [
  NUMBER,
  NUMBER,
]);

export const sqlite3_column_name: (stmt: number, index: number) => string = cwrap('sqlite3_column_name_x', STRING, [
  NUMBER,
  NUMBER,
]);

export const sqlite3_column_int: (stmt: number, index: number) => number = cwrap('sqlite3_column_int_x', NUMBER, [
  NUMBER,
  NUMBER,
]);

export const sqlite3_column_double: (stmt: number, index: number) => number = cwrap('sqlite3_column_double_x', NUMBER, [
  NUMBER,
  NUMBER,
]);

const sqlite3_column_text_x: (stmt: number, index: number) => 'null' = cwrap('sqlite3_column_text_x', NULL, [
  NUMBER,
  NUMBER,
]);

export const sqlite3_column_text = (stmt: number, index: number) => {
  sqlite3_column_text_x(stmt, index);
  return retrieveOutString();
};

export const sqlite3_finalize: (stmt: number, db: number) => null = cwrap('sqlite3_finalize_x', NULL, [NUMBER, NUMBER]);

export const sqlite3_finalize_silent: (stmt: number) => null = cwrap('sqlite3_finalize_silent_x', NULL, [NUMBER]);

export const sqlite3_reset: (stmt: number, db: number) => null = cwrap('sqlite3_reset_x', NULL, [NUMBER, NUMBER]);

export const sqlite3_clear_bindings: (stmt: number) => null = cwrap('sqlite3_clear_bindings_x', NULL, [NUMBER]);

export const sqlite3_exec: (db: number, sql: string) => null = cwrap('sqlite3_exec_x', NULL, [NUMBER, STRING]);

export const sqlite3_changes: (db: number) => number = cwrap('sqlite3_changes_x', NUMBER, [NUMBER]);

export const sqlite3_last_insert_rowid: (db: number) => number = cwrap('sqlite3_last_insert_rowid_x', NUMBER, [NUMBER]);