/*

 Exports a C-like API to the embedder.

 [obtain entrySource, entryPath]
 parseFile(entrySource, entryPath) -> parser
 while nextPath = nextFile(parser)
   [obtain nextSource]
   parseFile(nextSource, nextPath)

 Checking for errors:

 while diagnostic = nextDiagnostic(parser)
   [print] formatDiagnostic(diagnostic, useColors?, showContext?)
   if (isError(diagnostic))
     [abort parsing afterwards]

 compile(parser) -> module

 [check diagnostics again]
 [output module]

*/

import {
  Module
} from "./module";

import {
  Compiler,
  Options,
  Target
} from "./compiler";

import {
  DiagnosticMessage,
  DiagnosticCategory,
  formatDiagnosticMessage
} from "./diagnostics";

import {
  Parser
} from "./parser";

import {
  Program
} from "./program";

import {
  Decompiler
} from "./decompiler";

/** Parses a single source file. If `parser` has been omitted a new one is created. */
export function parseFile(text: string, path: string, parser: Parser | null = null, isEntry: bool = false): Parser {
  if (!parser) {
    parser = new Parser();
    isEntry = true;
  }
  parser.parseFile(text, path, isEntry);
  return parser;
}

/** Obtains the path to the next file required by the parser. Returns `null` once complete. */
export function nextFile(parser: Parser): string | null {
  return parser.nextFile();
}

/** Obtains the next diagnostic message. Returns `null` once there are no more messages. */
export function nextDiagnostic(parser: Parser): DiagnosticMessage | null {
  var program = parser.program;
  if (program.diagnosticsOffset < program.diagnostics.length)
    return program.diagnostics[program.diagnosticsOffset++];
  return null;
}

/** Formats a diagnostic message to a string. */
export function formatDiagnostic(message: DiagnosticMessage, useColors: bool, showContext: bool): string {
  return formatDiagnosticMessage(message, useColors, showContext);
}

/** Tests whether a diagnostic is informatory. */
export function isInfo(message: DiagnosticMessage): bool {
  return message.category == DiagnosticCategory.INFO;
}

/** Tests whether a diagnostic is a warning. */
export function isWarning(message: DiagnosticMessage): bool {
  return message.category == DiagnosticCategory.WARNING;
}

/** Tests whether a diagnostic is an error. */
export function isError(message: DiagnosticMessage): bool {
  return message.category == DiagnosticCategory.ERROR;
}

/** Creates a new set of compiler options. */
export function createOptions(): Options {
  return new Options();
}

/** Sets the `target` option. */
export function setTarget(options: Options, target: Target): void {
  options.target = target;
}

/** Sets the `noTreeShaking` option. */
export function setNoTreeShaking(options: Options, noTreeShaking: bool): void {
  options.noTreeShaking = noTreeShaking;
}

/** Sets the `noAssert` option. */
export function setNoAssert(options: Options, noAssert: bool): void {
  options.noAssert = noAssert;
}

/** Sets the `noMemory` option. */
export function setNoMemory(options: Options, noMemory: bool): void {
  options.noMemory = noMemory;
}

/** Compiles the sources computed by the parser to a module. */
export function compile(parser: Parser, options: Options | null = null): Module {
  var program = parser.finish();
  var compiler = new Compiler(program, options);
  return compiler.compile();
}

/** Decompiles a module to its (low level) source. */
export function decompile(module: Module): string {
  var decompiler = new Decompiler();
  decompiler.decompile(module);
  return decompiler.finish();
}