/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the Source EULA. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/

import * as ts from 'typescript';
import * as Lint from 'tslint';

/**
 * Implementation of the no-unexternalized-strings rule.
 */
export class Rule extends Lint.Rules.AbstractRule {
	public apply(sourceFile: ts.SourceFile): Lint.RuleFailure[] {
		return this.applyWithWalker(new NoUnexternalizedStringsRuleWalker(sourceFile, this.getOptions()));
	}
}

interface Map<V> {
	[key: string]: V;
}

interface UnexternalizedStringsOptions {
	signatures?: string[];
	messageIndex?: number;
	keyIndex?: number;
	ignores?: string[];
}

function isStringLiteral(node: ts.Node): node is ts.StringLiteral {
	return node && node.kind === ts.SyntaxKind.StringLiteral;
}

function isObjectLiteral(node: ts.Node): node is ts.ObjectLiteralExpression {
	return node && node.kind === ts.SyntaxKind.ObjectLiteralExpression;
}

function isPropertyAssignment(node: ts.Node): node is ts.PropertyAssignment {
	return node && node.kind === ts.SyntaxKind.PropertyAssignment;
}

interface KeyMessagePair {
	key: ts.StringLiteral;
	message: ts.Node | undefined;
}

class NoUnexternalizedStringsRuleWalker extends Lint.RuleWalker {

	private static ImportFailureMessage = 'Do not use double quotes for imports.';

	private static DOUBLE_QUOTE: string = '"';

	private signatures: Map<boolean>;
	private messageIndex: number | undefined;
	private keyIndex: number | undefined;
	private ignores: Map<boolean>;

	private usedKeys: Map<KeyMessagePair[]>;

	constructor(file: ts.SourceFile, opts: Lint.IOptions) {
		super(file, opts);
		this.signatures = Object.create(null);
		this.ignores = Object.create(null);
		this.messageIndex = undefined;
		this.keyIndex = undefined;
		this.usedKeys = Object.create(null);
		const options: any[] = this.getOptions();
		const first: UnexternalizedStringsOptions = options && options.length > 0 ? options[0] : null;
		if (first) {
			if (Array.isArray(first.signatures)) {
				first.signatures.forEach((signature: string) => this.signatures[signature] = true);
			}
			if (Array.isArray(first.ignores)) {
				first.ignores.forEach((ignore: string) => this.ignores[ignore] = true);
			}
			if (typeof first.messageIndex !== 'undefined') {
				this.messageIndex = first.messageIndex;
			}
			if (typeof first.keyIndex !== 'undefined') {
				this.keyIndex = first.keyIndex;
			}
		}
	}

	private static IDENTIFIER = /^[_a-zA-Z0-9][ .\-_a-zA-Z0-9]*$/;
	protected visitSourceFile(node: ts.SourceFile): void {
		super.visitSourceFile(node);
		Object.keys(this.usedKeys).forEach(key => {
			// Keys are quoted.
			let identifier = key.substr(1, key.length - 2);
			if (!NoUnexternalizedStringsRuleWalker.IDENTIFIER.test(identifier)) {
				let occurrence = this.usedKeys[key][0];
				this.addFailure(this.createFailure(occurrence.key.getStart(), occurrence.key.getWidth(), `The key ${occurrence.key.getText()} doesn't conform to a valid localize identifier`));
			}
			const occurrences = this.usedKeys[key];
			if (occurrences.length > 1) {
				occurrences.forEach(occurrence => {
					this.addFailure((this.createFailure(occurrence.key.getStart(), occurrence.key.getWidth(), `Duplicate key ${occurrence.key.getText()} with different message value.`)));
				});
			}
		});
	}

	protected visitStringLiteral(node: ts.StringLiteral): void {
		this.checkStringLiteral(node);
		super.visitStringLiteral(node);
	}

	private checkStringLiteral(node: ts.StringLiteral): void {
		const text = node.getText();
		const doubleQuoted = text.length >= 2 && text[0] === NoUnexternalizedStringsRuleWalker.DOUBLE_QUOTE && text[text.length - 1] === NoUnexternalizedStringsRuleWalker.DOUBLE_QUOTE;
		const info = this.findDescribingParent(node);
		// Ignore strings in import and export nodes.
		if (info && info.isImport && doubleQuoted) {
			const fix = [
				Lint.Replacement.replaceFromTo(node.getStart(), 1, '\''),
				Lint.Replacement.replaceFromTo(node.getStart() + text.length - 1, 1, '\''),
			];
			this.addFailureAtNode(
				node,
				NoUnexternalizedStringsRuleWalker.ImportFailureMessage,
				fix
			);
			return;
		}
		const callInfo = info ? info.callInfo : null;
		const functionName = callInfo ? callInfo.callExpression.expression.getText() : null;
		if (functionName && this.ignores[functionName]) {
			return;
		}

		if (doubleQuoted && (!callInfo || callInfo.argIndex === -1 || !this.signatures[functionName!])) {
			const s = node.getText();
			const fix = [
				Lint.Replacement.replaceFromTo(node.getStart(), node.getWidth(), `nls.localize('KEY-${s.substring(1, s.length - 1)}', ${s})`),
			];
			this.addFailure(this.createFailure(node.getStart(), node.getWidth(), `Unexternalized string found: ${node.getText()}`, fix));
			return;
		}
		// We have a single quoted string outside a localize function name.
		if (!doubleQuoted && !this.signatures[functionName!]) {
			return;
		}
		// We have a string that is a direct argument into the localize call.
		const keyArg: ts.Expression | null = callInfo && callInfo.argIndex === this.keyIndex
			? callInfo.callExpression.arguments[this.keyIndex]
			: null;
		if (keyArg) {
			if (isStringLiteral(keyArg)) {
				this.recordKey(keyArg, this.messageIndex && callInfo ? callInfo.callExpression.arguments[this.messageIndex] : undefined);
			} else if (isObjectLiteral(keyArg)) {
				for (let i = 0; i < keyArg.properties.length; i++) {
					const property = keyArg.properties[i];
					if (isPropertyAssignment(property)) {
						const name = property.name.getText();
						if (name === 'key') {
							const initializer = property.initializer;
							if (isStringLiteral(initializer)) {
								this.recordKey(initializer, this.messageIndex && callInfo ? callInfo.callExpression.arguments[this.messageIndex] : undefined);
							}
							break;
						}
					}
				}
			}
		}

		const messageArg = callInfo!.callExpression.arguments[this.messageIndex!];

		if (messageArg && messageArg.kind !== ts.SyntaxKind.StringLiteral) {
			this.addFailure(this.createFailure(
				messageArg.getStart(), messageArg.getWidth(),
				`Message argument to '${callInfo!.callExpression.expression.getText()}' must be a string literal.`));
			return;
		}
	}

	private recordKey(keyNode: ts.StringLiteral, messageNode: ts.Node | undefined) {
		const text = keyNode.getText();
		// We have an empty key
		if (text.match(/(['"]) *\1/)) {
			if (messageNode) {
				this.addFailureAtNode(keyNode, `Key is empty for message: ${messageNode.getText()}`);
			} else {
				this.addFailureAtNode(keyNode, `Key is empty.`);
			}
			return;
		}
		let occurrences: KeyMessagePair[] = this.usedKeys[text];
		if (!occurrences) {
			occurrences = [];
			this.usedKeys[text] = occurrences;
		}
		if (messageNode) {
			if (occurrences.some(pair => pair.message ? pair.message.getText() === messageNode.getText() : false)) {
				return;
			}
		}
		occurrences.push({ key: keyNode, message: messageNode });
	}

	private findDescribingParent(node: ts.Node): { callInfo?: { callExpression: ts.CallExpression, argIndex: number }, isImport?: boolean; } | null {
		let parent: ts.Node;
		while ((parent = node.parent)) {
			const kind = parent.kind;
			if (kind === ts.SyntaxKind.CallExpression) {
				const callExpression = parent as ts.CallExpression;
				return { callInfo: { callExpression: callExpression, argIndex: callExpression.arguments.indexOf(<any>node) } };
			} else if (kind === ts.SyntaxKind.ImportEqualsDeclaration || kind === ts.SyntaxKind.ImportDeclaration || kind === ts.SyntaxKind.ExportDeclaration) {
				return { isImport: true };
			} else if (kind === ts.SyntaxKind.VariableDeclaration || kind === ts.SyntaxKind.FunctionDeclaration || kind === ts.SyntaxKind.PropertyDeclaration
				|| kind === ts.SyntaxKind.MethodDeclaration || kind === ts.SyntaxKind.VariableDeclarationList || kind === ts.SyntaxKind.InterfaceDeclaration
				|| kind === ts.SyntaxKind.ClassDeclaration || kind === ts.SyntaxKind.EnumDeclaration || kind === ts.SyntaxKind.ModuleDeclaration
				|| kind === ts.SyntaxKind.TypeAliasDeclaration || kind === ts.SyntaxKind.SourceFile) {
				return null;
			}
			node = parent;
		}
		return null;
	}
}