/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */
import {error} from '../utils/console';

import {COMMIT_TYPES, getCommitMessageConfig, ScopeRequirement} from './config';
import {parseCommitMessage, ParsedCommitMessage} from './parse';

/** Options for commit message validation. */
export interface ValidateCommitMessageOptions {
 disallowSquash?: boolean;
 nonFixupCommitHeaders?: string[];
}

/** The result of a commit message validation check. */
export interface ValidateCommitMessageResult {
 valid: boolean;
 errors: string[];
 commit: ParsedCommitMessage;
}

/** Regex matching a URL for an entire commit body line. */
const COMMIT_BODY_URL_LINE_RE = /^https?:\/\/.*$/;
/**
 * Regex matching a breaking change.
 *
 * - Starts with BREAKING CHANGE
 * - Followed by a colon
 * - Followed by a single space or two consecutive new lines
 *
 * NB: Anything after `BREAKING CHANGE` is optional to facilitate the validation.
 */
const COMMIT_BODY_BREAKING_CHANGE_RE = /^BREAKING CHANGE(:( |\n{2}))?/m;

/** Validate a commit message against using the local repo's config. */
export function validateCommitMessage(
 commitMsg: string|ParsedCommitMessage,
 options: ValidateCommitMessageOptions = {}): ValidateCommitMessageResult {
 const config = getCommitMessageConfig().commitMessage;
 const commit = typeof commitMsg === 'string' ? parseCommitMessage(commitMsg) : commitMsg;
 const errors: string[] = [];

 /** Perform the validation checks against the parsed commit. */
 function validateCommitAndCollectErrors() {
 // TODO(josephperrott): Remove early return calls when commit message errors are found

 ////////////////////////////////////
 // Checking revert, squash, fixup //
 ////////////////////////////////////

 // All revert commits are considered valid.
 if (commit.isRevert) {
 return true;
 }

 // All squashes are considered valid, as the commit will be squashed into another in
 // the git history anyway, unless the options provided to not allow squash commits.
 if (commit.isSquash) {
 if (options.disallowSquash) {
 errors.push('The commit must be manually squashed into the target commit');
 return false;
 }
 return true;
 }

 // Fixups commits are considered valid, unless nonFixupCommitHeaders are provided to check
 // against. If `nonFixupCommitHeaders` is not empty, we check whether there is a corresponding
 // non-fixup commit (i.e. a commit whose header is identical to this commit's header after
 // stripping the `fixup! ` prefix), otherwise we assume this verification will happen in another
 // check.
 if (commit.isFixup) {
 if (options.nonFixupCommitHeaders && !options.nonFixupCommitHeaders.includes(commit.header)) {
 errors.push(
 'Unable to find match for fixup commit among prior commits: ' +
 (options.nonFixupCommitHeaders.map(x => `\n ${x}`).join('') || '-'));
 return false;
 }

 return true;
 }

 ////////////////////////////
 // Checking commit header //
 ////////////////////////////
 if (commit.header.length > config.maxLineLength) {
 errors.push(`The commit message header is longer than ${config.maxLineLength} characters`);
 return false;
 }

 if (!commit.type) {
 errors.push(`The commit message header does not match the expected format.`);
 return false;
 }

 if (COMMIT_TYPES[commit.type] === undefined) {
 errors.push(`'${commit.type}' is not an allowed type.\n => TYPES: ${
 Object.keys(COMMIT_TYPES).join(', ')}`);
 return false;
 }

 /** The scope requirement level for the provided type of the commit message. */
 const scopeRequirementForType = COMMIT_TYPES[commit.type].scope;

 if (scopeRequirementForType === ScopeRequirement.Forbidden && commit.scope) {
 errors.push(`Scopes are forbidden for commits with type '${commit.type}', but a scope of '${
 commit.scope}' was provided.`);
 return false;
 }

 if (scopeRequirementForType === ScopeRequirement.Required && !commit.scope) {
 errors.push(
 `Scopes are required for commits with type '${commit.type}', but no scope was provided.`);
 return false;
 }

 if (commit.scope && !config.scopes.includes(commit.scope)) {
 errors.push(
 `'${commit.scope}' is not an allowed scope.\n => SCOPES: ${config.scopes.join(', ')}`);
 return false;
 }

 // Commits with the type of `release` do not require a commit body.
 if (commit.type === 'release') {
 return true;
 }

 //////////////////////////
 // Checking commit body //
 //////////////////////////

 if (!config.minBodyLengthTypeExcludes?.includes(commit.type) &&
 commit.bodyWithoutLinking.trim().length < config.minBodyLength) {
 errors.push(`The commit message body does not meet the minimum length of ${
 config.minBodyLength} characters`);
 return false;
 }

 const bodyByLine = commit.body.split('\n');
 const lineExceedsMaxLength = bodyByLine.some(line => {
 // Check if any line exceeds the max line length limit. The limit is ignored for
 // lines that just contain an URL (as these usually cannot be wrapped or shortened).
 return line.length > config.maxLineLength && !COMMIT_BODY_URL_LINE_RE.test(line);
 });

 if (lineExceedsMaxLength) {
 errors.push(`The commit message body contains lines greater than ${
 config.maxLineLength} characters.`);
 return false;
 }

 // Breaking change
 // Check if the commit message contains a valid break change description.
 // https://github.com/angular/angular/blob/88fbc066775ab1a2f6a8c75f933375b46d8fa9a4/CONTRIBUTING.md#commit-message-footer
 const hasBreakingChange = COMMIT_BODY_BREAKING_CHANGE_RE.exec(commit.body);
 if (hasBreakingChange !== null) {
 const [, breakingChangeDescription] = hasBreakingChange;
 if (!breakingChangeDescription) {
 // Not followed by :, space or two consecutive new lines,
 errors.push(`The commit message body contains an invalid breaking change description.`);
 return false;
 }
 }

 return true;
 }

 return {valid: validateCommitAndCollectErrors(), errors, commit};
}


/** Print the error messages from the commit message validation to the console. */
export function printValidationErrors(errors: string[], print = error) {
 print.group(`Error${errors.length === 1 ? '' : 's'}:`);
 errors.forEach(line => print(line));
 print.groupEnd();
 print();
 print('The expected format for a commit is: ');
 print('<type>(<scope>): <summary>');
 print();
 print('<body>');
 print();
 print(`BREAKING CHANGE: <breaking change summary>`);
 print();
 print(`<breaking change description>`);
 print();
 print();
}