import { isString } from '@sindresorhus/is';
import { split } from 'shlex';
import upath from 'upath';
import { logger } from '../../../logger/index.ts';
import { coerceArray, isNotNullOrUndefined } from '../../../util/array.ts';
import type {
  ExecOptions,
  ExtraEnv,
  ToolConstraint,
} from '../../../util/exec/types.ts';
import { ensureCacheDir } from '../../../util/fs/index.ts';
import { ensureLocalPath } from '../../../util/fs/util.ts';
import * as hostRules from '../../../util/host-rules.ts';
import { regEx } from '../../../util/regex.ts';
import { parseUrl } from '../../../util/url.ts';
import type { PackageFileContent, UpdateArtifactsConfig } from '../types.ts';
import type {
  CommandType,
  PipCompileArgs,
  SupportedManagers,
} from './types.ts';

export function getPythonVersionConstraint(
  config: UpdateArtifactsConfig,
  extractedPythonVersion: string | undefined,
): string | undefined | null {
  const { constraints = {} } = config;
  const { python } = constraints;

  if (python) {
    logger.debug('Using python constraint from config');
    return python;
  }

  if (extractedPythonVersion) {
    logger.debug('Using python constraint extracted from the lock file');
    return `==${extractedPythonVersion}`;
  }

  return undefined;
}

export function getPipToolsVersionConstraint(
  config: UpdateArtifactsConfig,
): string {
  const { constraints = {} } = config;
  const { pipTools } = constraints;

  if (isString(pipTools)) {
    logger.debug('Using pipTools constraint from config');
    return pipTools;
  }

  return '';
}

export function getUvVersionConstraint(config: UpdateArtifactsConfig): string {
  const { constraints = {} } = config;
  const { uv } = constraints;

  if (isString(uv)) {
    logger.debug('Using uv constraint from config');
    return uv;
  }

  return '';
}

export function getToolVersionConstraint(
  config: UpdateArtifactsConfig,
  commandType: CommandType,
): ToolConstraint {
  if (commandType === 'uv') {
    return {
      toolName: 'uv',
      constraint: getUvVersionConstraint(config),
    };
  }

  return {
    toolName: 'pip-tools',
    constraint: getPipToolsVersionConstraint(config),
  };
}

export async function getExecOptions(
  config: UpdateArtifactsConfig,
  commandType: CommandType,
  cwd: string,
  extraEnv: ExtraEnv<string>,
  extractedPythonVersion: string | undefined,
): Promise<ExecOptions> {
  const constraint = getPythonVersionConstraint(config, extractedPythonVersion);
  const execOptions: ExecOptions = {
    cwd: ensureLocalPath(cwd),
    docker: {},
    toolConstraints: [
      {
        toolName: 'python',
        constraint,
      },
      getToolVersionConstraint(config, commandType),
    ],
    extraEnv: {
      PIP_CACHE_DIR: await ensureCacheDir('pip'),
      PIP_NO_INPUT: 'true', // ensure pip doesn't block forever waiting for credentials on stdin
      PIP_KEYRING_PROVIDER: 'import',
      PYTHON_KEYRING_BACKEND: 'keyrings.envvars.keyring.EnvvarsKeyring',
      ...extraEnv,
    },
  };
  return execOptions;
}

export const constraintLineRegex = regEx(
  /^(?:#.*?\r?\n)+# {4}(?<command>\S*)(?<arguments> .*?)?\r?\n/,
);

export const disallowedPipOptions = [
  '--no-header', // header is required by this manager
];
const commonOptionsWithArguments = [
  '--output-file',
  '--extra',
  '--extra-index-url',
];
const pipOptionsWithArguments = [
  '--resolver',
  '--constraint',
  ...commonOptionsWithArguments,
];
const uvOptionsWithArguments = [
  '--constraints',
  '--constraint', // singular alias accepted by uv
  '--python-version',
  '--no-emit-package',
  '--prerelease',
  '--format',
  '--resolution',
  '--fork-strategy',
  '--exclude-newer',
  '--exclude-newer-package',
  '--group',
  '--override',
  '--overrides',
  ...commonOptionsWithArguments,
];
export const optionsWithArguments = [
  ...pipOptionsWithArguments,
  ...uvOptionsWithArguments,
];
const allowedCommonOptions = [
  '-v',
  '--generate-hashes',
  '--emit-index-url',
  '--index-url',
  '--all-extras',
];
export const allowedOptions: Record<CommandType, string[]> = {
  'pip-compile': [
    '--allow-unsafe',
    '--generate-hashes',
    '--no-emit-index-url',
    '--strip-extras',
    ...allowedCommonOptions,
    ...pipOptionsWithArguments,
  ],
  uv: [
    '--no-strip-extras',
    '--universal',
    ...allowedCommonOptions,
    ...uvOptionsWithArguments,
  ],
  custom: [],
};

// TODO(not7cd): test on all correct headers, even with CUSTOM_COMPILE_COMMAND
export function extractHeaderCommand(
  content: string,
  fileName: string,
): PipCompileArgs {
  const compileCommand = constraintLineRegex.exec(content);
  if (compileCommand?.groups === undefined) {
    throw new Error(
      `Failed to extract command from header in ${fileName} ${content}`,
    );
  }
  logger.trace(
    `pip-compile: found header in ${fileName}: \n${compileCommand[0]}`,
  );
  const command = compileCommand.groups.command;
  const argv = [command];
  let commandType: CommandType;
  if (command === 'pip-compile') {
    commandType = 'pip-compile';
  } else if (command === 'uv') {
    commandType = 'uv';
  } else {
    commandType = 'custom';
  }
  if (compileCommand.groups.arguments) {
    argv.push(...split(compileCommand.groups.arguments));
  }
  logger.debug(
    { fileName, argv, commandType },
    `pip-compile: extracted command from header`,
  );

  const result: PipCompileArgs = {
    argv,
    command,
    commandType,
    outputFile: '',
    sourceFiles: [],
  };
  for (const arg of argv.slice(1)) {
    if (commandType === 'uv' && ['pip', 'compile'].includes(arg)) {
      continue;
    }
    // TODO(not7cd): check for "--option -- argument" case
    if (!arg.startsWith('-')) {
      result.sourceFiles.push(arg);
      continue;
    }
    throwForDisallowedOption(arg);
    throwForNoEqualSignInOptionWithArgument(arg);
    throwForUnknownOption(commandType, arg);

    if (arg.includes('=')) {
      const [option, value] = arg.split('=');
      if (option === '--extra') {
        result.extra = coerceArray(result.extra);
        result.extra.push(value);
      } else if (option === '--extra-index-url') {
        result.extraIndexUrl = coerceArray(result.extraIndexUrl);
        result.extraIndexUrl.push(value);
        // TODO: add to secrets? next PR
      } else if (['--constraint', '--constraints'].includes(option)) {
        result.constraintsFiles = coerceArray(result.constraintsFiles);
        result.constraintsFiles.push(value);
      } else if (['--override', '--overrides'].includes(option)) {
        result.overridesFiles = coerceArray(result.overridesFiles);
        result.overridesFiles.push(value);
      } else if (option === '--output-file') {
        if (result.outputFile) {
          throw new Error('Cannot use multiple --output-file options');
        }
        result.outputFile = upath.normalize(value);
      } else if (option === '--python-version') {
        result.pythonVersion = value;
      } else if (option === '--index-url') {
        if (result.indexUrl) {
          throw new Error('Cannot use multiple --index-url options');
        }
        result.indexUrl = value;
        // TODO: add to secrets? next PR
      } else {
        logger.debug({ option }, `pip-compile: option not handled`);
      }
      continue;
    }
    if (arg === '--no-emit-index-url') {
      result.noEmitIndexUrl = true;
      continue;
    }
    if (arg === '--emit-index-url') {
      result.emitIndexUrl = true;
      continue;
    }
    if (arg === '--all-extras') {
      result.allExtras = true;
      continue;
    }

    logger.debug({ option: arg }, `pip-compile: option not handled`);
  }
  logger.trace(
    {
      ...result,
    },
    'Parsed pip-compile command from header',
  );
  if (result.noEmitIndexUrl && result.emitIndexUrl) {
    throw new Error('Cannot use both --no-emit-index-url and --emit-index-url');
  }
  if (result.sourceFiles.length === 0) {
    throw new Error(
      'No source files detected in command, pass at least one package file explicitly',
    );
  }
  return result;
}

const pythonVersionRegex = regEx(
  /^(?:#.*?\r?\n)*# This file is autogenerated by pip-compile with Python (?<pythonVersion>\d+(?:\.\d+)*)\s/,
  'i',
);

export function extractPythonVersion(
  content: string,
  fileName: string,
): string | undefined {
  const match = pythonVersionRegex.exec(content);
  if (match?.groups === undefined) {
    logger.warn(
      { fileName, content },
      'pip-compile: failed to extract Python version from header in file',
    );
    return undefined;
  }
  logger.trace(
    `pip-compile: found Python version header in ${fileName}: \n${match[0]}`,
  );
  const { pythonVersion } = match.groups;
  logger.debug(
    { fileName, pythonVersion },
    `pip-compile: extracted Python version from header`,
  );
  return pythonVersion;
}

function throwForDisallowedOption(arg: string): void {
  if (disallowedPipOptions.includes(arg)) {
    throw new Error(`Option ${arg} not allowed for this manager`);
  }
}
function throwForNoEqualSignInOptionWithArgument(arg: string): void {
  if (optionsWithArguments.includes(arg)) {
    throw new Error(
      `Option ${arg} must have equal sign '=' separating it's argument`,
    );
  }
}
function throwForUnknownOption(commandType: CommandType, arg: string): void {
  if (arg.includes('=')) {
    const [option] = arg.split('=');
    if (allowedOptions[commandType].includes(option)) {
      return;
    }
  }
  if (allowedOptions[commandType].includes(arg)) {
    return;
  }
  throw new Error(`Option ${arg} not supported (yet)`);
}

function getRegistryCredEnvVars(
  url: URL,
  index: number,
): Record<string, string> {
  const hostRule = hostRules.find({ url: url.href });
  logger.debug(hostRule, `Found host rule for url ${url.href}`);
  const ret: Record<string, string> = {};
  if (!!hostRule.username || !!hostRule.password) {
    ret[`KEYRING_SERVICE_NAME_${index}`] = url.hostname;
    ret[`KEYRING_SERVICE_USERNAME_${index}`] = hostRule.username ?? '';
    ret[`KEYRING_SERVICE_PASSWORD_${index}`] = hostRule.password ?? '';
  }
  return ret;
}

function cleanUrl(url: string): URL | null {
  // Strip everything but protocol, host, and port
  const urlObj = parseUrl(url);
  if (!urlObj) {
    return null;
  }
  // origin of a valid URL is always parseable
  return parseUrl(urlObj.origin);
}

export function getRegistryCredVarsFromPackageFiles(
  packageFiles: PackageFileContent[],
): ExtraEnv<string> {
  const urls: string[] = [];
  for (const packageFile of packageFiles) {
    urls.push(
      ...coerceArray(packageFile.registryUrls),
      ...coerceArray(packageFile.additionalRegistryUrls),
    );
  }
  logger.debug(urls, 'Extracted registry URLs from package files');

  const uniqueHosts = new Set<URL>(
    urls.map(cleanUrl).filter(isNotNullOrUndefined),
  );

  let allCreds: ExtraEnv<string> = {};
  for (const [index, host] of [...uniqueHosts].entries()) {
    const hostCreds = getRegistryCredEnvVars(host, index);
    allCreds = {
      ...allCreds,
      ...hostCreds,
    };
  }

  return allCreds;
}

export function matchManager(filename: string): SupportedManagers | 'unknown' {
  if (filename.endsWith('setup.py')) {
    return 'pip_setup';
  }
  if (filename.endsWith('setup.cfg')) {
    return 'setup-cfg';
  }
  if (filename.endsWith('pyproject.toml')) {
    return 'pep621';
  }
  // naive, could be improved, maybe use pip_requirements.managerFilePatterns
  if (filename.endsWith('.in') || filename.endsWith('.txt')) {
    return 'pip_requirements';
  }
  return 'unknown';
}