class Control {
    constructor(stream, raw) {
        this.data = "";
        this.tmp = "";

        this.stream = stream;
        this.raw = typeof raw !== 'undefined' ? raw : true
        if (this.raw) {
            this.stream.setRawMode(true);
            this.stream.resume();
            this.stream.setEncoding('utf8');
        }
        this.stream.on('data', data => this.inputHandler(data));

        this.cursorPosition = 0;
        this.commandHistory = ['console.log("This is a test command in history")', 'console.log("search test")'];
        this.historyPosition = this.commandHistory.length;
        this.searchIndex = this.commandHistory.length - 1;
        this.prevSearch = "";
    }

    processCommand(cmd) {
        if (cmd === "") { return }
        if (cmd !== this.commandHistory[this.commandHistory.length-1]) {
            this.commandHistory.push(cmd);
        }
        this.historyPosition = this.commandHistory.length;
    }

    inputHandler(data) {
        switch (data) {
            case '\u0003':
                // ctrl-c
                process.exit();
                break;
            case '\u0012':
                // ctrl-r
                this.search();
                break;
            case '\u001B\u005B\u0041':
                // up arrow
                this.showPrevCommand();
                break;
            case '\u001B\u005B\u0042':
                // down arrow
                this.showNextCommand();
                break;
            case '\u001B\u005B\u0044':
                // left arrow
                this.moveCursor('left');
                break;
            case '\u001B\u005B\u0043':
                // right arrow
                this.moveCursor('right');
                break;
            case '\u001B\u0062':
                // alt + left arrow
                this.moveCursor('left', true);
                break;
            case '\u001B\u0066':
                // alt + right arrow
                this.moveCursor('right', true);
                break;
            case '\u000D':
                // enter key
                this.stream.write("\n");
                this.processCommand(this.data);
                this.clearInput();
                this.data = "";
                this.tmp = "";
                break;
            case '\u007F':
                // backspace
                this.deleteCharacter();
                break;
            case '\u0009':
                // tab
                break;
            default:
                if (this.raw) {
                    this.addCharacter(data);
                } else {
                    this.data += data;
                    let cmd;
                    while (cmd = this.sliceCommand()){
                        this.processCommand(cmd);
                    }
                }
        }
    }

    clearInput() {
        if (!this.raw) { return }
        this.stream.write("\r" + Array(this.data.length).fill(" ").join("") + "\r");
    }

    moveCursor(direction, toWord) {
        if (direction === 'left') {
            this.cursorPosition = Math.max(0, this.cursorPosition - 1);
            if (toWord) {
                const idx = this.data.slice(0,this.cursorPosition).split("").reverse().join("").search(/\w[^\w]/);
                if (idx > -1) {
                    this.cursorPosition = Math.max(0, this.cursorPosition - idx - 1);
                } else {
                    this.cursorPosition = 0;
                }
            }
        } else if (direction === 'right') {
            this.cursorPosition = Math.min(this.data.length, this.cursorPosition + 1);
            if (toWord) {
                const idx = this.data.slice(this.cursorPosition).search(/[^\w]\w/);
                if (idx > -1) {
                    this.cursorPosition = Math.min(this.data.length, this.cursorPosition + idx + 1);
                } else {
                    this.cursorPosition = this.data.length;
                }
            }
        }
        this.stream.write("\r" + this.data.slice(0, this.cursorPosition));
    }

    updateLine(ifAtEnd) {
        if (this.cursorPosition === this.data.length) {
            this.stream.write(ifAtEnd);
        } else {
            this.stream.write("\r" + this.data);
            this.stream.write("\r" + this.data.slice(0, this.cursorPosition));
        }
    }

    addCharacter(character) {
        this.data = this.data.slice(0, this.cursorPosition) + character + this.data.slice(this.cursorPosition);
        this.tmp = this.data;
        this.cursorPosition++;
        this.updateLine(character);
    }

    deleteCharacter() {
        this.clearInput();
        this.data = this.data.slice(0, this.cursorPosition - 1) + this.data.slice(this.cursorPosition);
        this.tmp = this.data;
        this.cursorPosition = Math.max(0, this.cursorPosition - 1);
        this.updateLine(this.data);
    }

    showCommand(cmd) {
        this.clearInput();
        this.data = cmd;
        this.cursorPosition = this.data.length;
        this.stream.write("\r" + this.data);
    }

    showPrevCommand() {
        if (this.historyPosition > 0) {
            this.historyPosition--;
            this.showCommand(this.commandHistory[this.historyPosition]);
        }
    }

    showNextCommand() {
        if (this.historyPosition <= this.commandHistory.length - 1) {
            this.historyPosition++;
            this.showCommand(this.commandHistory[this.historyPosition] || this.tmp);
        } else {
            this.showCommand("");
        }
    }

    lookUp(start) {
        for (let i=start; i>-1; i--) {
            if (this.commandHistory[i].match(this.tmp)) {
                this.searchIndex = i - 1;
                this.showCommand(this.commandHistory[i]);
                return true;
            }
        }

        for (let i=this.commandHistory.length - 1; i>start; i--) {
            if (this.commandHistory[i].match(this.tmp)) {
                this.searchIndex = i - 1;
                this.showCommand(this.commandHistory[i]);
                return true;
            }
        }
    }

    search() {
        if (this.tmp === "") { return }

        if (this.tmp !== this.prevSearch) {
            this.searchIndex = this.commandHistory.length - 1;
            this.prevSearch = this.tmp
        }
        this.lookUp(this.searchIndex);
    }

    sliceCommand() {
        if (this.data.indexOf("\n") > -1){
            const cmd = this.data.split("\n")[0];
            this.data = this.data.slice(this.data.indexOf("\n") + 1);
            return cmd;
        }
    }
}

class EvalControl extends Control {
    processCommand(cmd) {
        super.processCommand();
        try {
            eval(cmd);
        } catch (e) {
            console.log(cmd);
        }
    }
}

module.exports = {Control, EvalControl}