import { DebugSession, InitializedEvent, TerminatedEvent, StoppedEvent, OutputEvent, Thread, StackFrame, Scope, Source, Handles } from 'vscode-debugadapter';
import { DebugProtocol } from 'vscode-debugprotocol';
import { Breakpoint, IBackend } from './backend/backend';
import { MINode } from './backend/mi_parse';
import { expandValue, isExpandable } from './backend/gdb_expansion';
import { MI2 } from './backend/mi2/mi2';
import { posix } from "path";
import * as systemPath from "path";

let resolve = posix.resolve;
let relative = posix.relative;

export class MI2DebugSession extends DebugSession {
	protected static THREAD_ID = 1;
	protected variableHandles = new Handles<any>();
	protected quit: boolean;
	protected attached: boolean;
	protected needContinue: boolean;
	protected isSSH: boolean;
	protected trimCWD: string;
	protected switchCWD: string;
	protected started: boolean;
	protected crashed: boolean;
	protected miDebugger: MI2;

	public constructor(debuggerLinesStartAt1: boolean, isServer: boolean = false) {
		super(debuggerLinesStartAt1, isServer);
	}
	
	protected initDebugger() {
		this.miDebugger.on("quit", this.quitEvent.bind(this));
		this.miDebugger.on("exited-normally", this.quitEvent.bind(this));
		this.miDebugger.on("stopped", this.stopEvent.bind(this));
		this.miDebugger.on("msg", this.handleMsg.bind(this));
		this.miDebugger.on("breakpoint", this.handleBreakpoint.bind(this));
		this.miDebugger.on("step-end", this.handleBreak.bind(this));
		this.miDebugger.on("step-out-end", this.handleBreak.bind(this));
		this.miDebugger.on("signal-stop", this.handlePause.bind(this));
		this.sendEvent(new InitializedEvent());
	}

	protected handleMsg(type: string, msg: string) {
		if (type == "target")
			type = "stdout";
		if (type == "log")
			type = "stderr";
		this.sendEvent(new OutputEvent(msg, type));
	}

	protected handleBreakpoint(info: MINode) {
		this.sendEvent(new StoppedEvent("breakpoint", MI2DebugSession.THREAD_ID));
	}

	protected handleBreak(info: MINode) {
		this.sendEvent(new StoppedEvent("step", MI2DebugSession.THREAD_ID));
	}

	protected handlePause(info: MINode) {
		this.sendEvent(new StoppedEvent("user request", MI2DebugSession.THREAD_ID));
	}

	protected stopEvent(info: MINode) {
		if (!this.started)
			this.crashed = true;
		if (!this.quit)
			this.sendEvent(new StoppedEvent("exception", MI2DebugSession.THREAD_ID));
	}

	protected quitEvent() {
		this.quit = true;
		this.sendEvent(new TerminatedEvent());
	}

	protected disconnectRequest(response: DebugProtocol.DisconnectResponse, args: DebugProtocol.DisconnectArguments): void {
		if (this.attached)
			this.miDebugger.detach();
		else
			this.miDebugger.stop();
		this.sendResponse(response);
	}

	protected setBreakPointsRequest(response: DebugProtocol.SetBreakpointsResponse, args: DebugProtocol.SetBreakpointsArguments): void {
		this.miDebugger.once("debug-ready", (() => {
			this.miDebugger.clearBreakPoints().then(() => {
				let path = args.source.path;
				if (this.isSSH) {
					path = relative(this.trimCWD.replace(/\\/g, "/"), path.replace(/\\/g, "/"));
					path = resolve(this.switchCWD.replace(/\\/g, "/"), path.replace(/\\/g, "/"));
				}
				let all = [];
				args.breakpoints.forEach(brk => {
					all.push(this.miDebugger.addBreakPoint({ file: path, line: brk.line, condition: brk.condition }));
				});
				Promise.all(all).then(brkpoints => {
					let finalBrks = [];
					brkpoints.forEach(brkp => {
						if (brkp[0])
							finalBrks.push({ line: brkp[1].line });
					});
					response.body = {
						breakpoints: finalBrks
					};
					setTimeout(() => {
						this.miDebugger.emit("ui-break-done");
					}, 50);
					this.sendResponse(response);
				});
			});
		}).bind(this));
	}

	protected threadsRequest(response: DebugProtocol.ThreadsResponse): void {
		response.body = {
			threads: [
				new Thread(MI2DebugSession.THREAD_ID, "Thread 1")
			]
		};
		this.sendResponse(response);
	}

	protected stackTraceRequest(response: DebugProtocol.StackTraceResponse, args: DebugProtocol.StackTraceArguments): void {
		this.miDebugger.getStack(args.levels).then(stack => {
			let ret: StackFrame[] = [];
			stack.forEach(element => {
				let file = element.file;
				if (this.isSSH) {
					file = relative(this.switchCWD.replace(/\\/g, "/"), file.replace(/\\/g, "/"));
					file = systemPath.resolve(this.trimCWD.replace(/\\/g, "/"), file.replace(/\\/g, "/"));
				}
				ret.push(new StackFrame(element.level, element.function + "@" + element.address, new Source(element.fileName, file), element.line, 0));
			});
			response.body = {
				stackFrames: ret
			};
			this.sendResponse(response);
		});
	}

	protected configurationDoneRequest(response: DebugProtocol.ConfigurationDoneResponse, args: DebugProtocol.ConfigurationDoneArguments): void {
		// FIXME: Does not seem to get called in january release
		if (this.needContinue) {
			this.miDebugger.continue().then(done => {
				this.sendResponse(response);
			}, msg => {
				this.sendResponse(response);
				this.sendEvent(new OutputEvent(`Could not continue: ${msg}\n`, 'stderr'));
			});
		}
		else
			this.sendResponse(response);
	}

	protected scopesRequest(response: DebugProtocol.ScopesResponse, args: DebugProtocol.ScopesArguments): void {
		const scopes = new Array<Scope>();
		scopes.push(new Scope("Local", this.variableHandles.create("@frame:" + args.frameId), false));

		response.body = {
			scopes: scopes
		};
		this.sendResponse(response);
	}

	protected variablesRequest(response: DebugProtocol.VariablesResponse, args: DebugProtocol.VariablesArguments): void {
		const variables = [];
		const id = this.variableHandles.get(args.variablesReference);

		let createVariable = (arg) => {
			return this.variableHandles.create(arg);
		};

		if (typeof id == "string") {
			if (id.startsWith("@frame:")) {
				this.miDebugger.getStackVariables(1, 0).then(stack => {
					stack.forEach(variable => {
						if (variable[1] !== undefined) {
							let expanded = expandValue(createVariable, `{${variable[0]} = ${variable[1]}}`);
							if (!expanded)
								new OutputEvent("Could not expand " + variable[1] + "\n", "stderr");
							else if (typeof expanded[0] == "string")
								expanded = [
									{
										name: "<value>",
										value: prettyStringArray(expanded),
										variablesReference: 0
									}
								];
							variables.push(expanded[0]);
						} else
							variables.push({
								name: variable[0],
								value: "<unknown>",
								variablesReference: createVariable(variable[0])
							});
					});
					response.body = {
						variables: variables
					};
					this.sendResponse(response);
				}, err => {
					this.handleMsg("stderr", "Could not expand variable\n");
					response.body = {
						variables: []
					};
					this.sendResponse(response);
				});
			}
			else {
				// Variable members
				this.miDebugger.evalExpression(JSON.stringify(id)).then(variable => {
					let expanded = expandValue(createVariable, variable.result("value"), id);
					if (!expanded)
						this.sendEvent(new OutputEvent("Could not expand " + variable.result("value") + "\n", "stderr"));
					else if (typeof expanded[0] == "string")
						expanded = [
							{
								name: "<value>",
								value: prettyStringArray(expanded),
								variablesReference: 0
							}
						];
					response.body = {
						variables: expanded
					};
					this.sendResponse(response);
				}, err => {
					this.handleMsg("stderr", "Could not expand variable\n");
					response.body = {
						variables: []
					};
					this.sendResponse(response);
				});
			}
		}
		else if (typeof id == "object") {
			response.body = {
				variables: id
			};
			this.sendResponse(response);
		}
		else {
			response.body = {
				variables: variables
			};
			this.sendResponse(response);
		}
	}

	protected pauseRequest(response: DebugProtocol.ContinueResponse, args: DebugProtocol.ContinueArguments): void {
		this.miDebugger.interrupt().then(done => {
			this.sendResponse(response);
		}, msg => {
			this.sendResponse(response);
			this.sendEvent(new OutputEvent(`Could not pause: ${msg}\n`, 'stderr'));
		});
	}

	protected continueRequest(response: DebugProtocol.ContinueResponse, args: DebugProtocol.ContinueArguments): void {
		this.miDebugger.continue().then(done => {
			this.sendResponse(response);
		}, msg => {
			this.sendResponse(response);
			this.sendEvent(new OutputEvent(`Could not continue: ${msg}\n`, 'stderr'));
		});
	}

	protected stepInRequest(response: DebugProtocol.NextResponse, args: DebugProtocol.NextArguments): void {
		this.miDebugger.step().then(done => {
			this.sendResponse(response);
		}, msg => {
			this.sendResponse(response);
			this.sendEvent(new OutputEvent(`Could not step in: ${msg}\n`, 'stderr'));
		});
	}

	protected stepOutRequest(response: DebugProtocol.NextResponse, args: DebugProtocol.NextArguments): void {
		this.miDebugger.stepOut().then(done => {
			this.sendResponse(response);
		}, msg => {
			this.sendResponse(response);
			this.sendEvent(new OutputEvent(`Could not step out: ${msg}\n`, 'stderr'));
		});
	}

	protected nextRequest(response: DebugProtocol.NextResponse, args: DebugProtocol.NextArguments): void {
		this.miDebugger.next().then(done => {
			this.sendResponse(response);
		}, msg => {
			this.sendResponse(response);
			this.sendEvent(new OutputEvent(`Could not step over: ${msg}\n`, 'stderr'));
		});
	}

	protected evaluateRequest(response: DebugProtocol.EvaluateResponse, args: DebugProtocol.EvaluateArguments): void {
		if (args.context == "watch" || args.context == "hover")
			this.miDebugger.evalExpression(args.expression).then((res) => {
				response.body = {
					variablesReference: 0,
					result: res.result("value")
				}
				this.sendResponse(response);
			});
		else {
			this.miDebugger.sendUserInput(args.expression).then(output => {
				if (output)
					response.body.result = JSON.stringify(output);
				this.sendResponse(response);
			});
		}
	}
}

function prettyStringArray(strings: string[]) {
	return strings.join(", ");
}