import * as assert from 'assert';
import { ModeName } from '../src/mode/mode'
import { Position } from '../src/motion/position';
import { ModeHandler } from '../src/mode/modeHandler';
import { TextEditor } from '../src/textEditor';
import { assertEqualLines } from './testUtils';


interface TestObject {
    start: string[],
    keysPressed: string,
    end: string[],
    endMode?: ModeName
}

class TestObjectHelper {
    startPosition = new Position(0, 0);
    endPosition = new Position(0, 0);
    private _isValid = false;
    
    constructor(private _testObject: TestObject) {
        this._parse(_testObject);
    }

    public get isValid(): boolean {
        return this._isValid;
    }
    
    private _setStartCursorPosition(lines: string[]): boolean {
        let result = this._getCursorPosition(lines);
        this.startPosition = result.position;
        return result.success;
    }

    private _setEndCursorPosition(lines: string[]): boolean {
        let result = this._getCursorPosition(lines);
        this.endPosition = result.position;
        return result.success;
    }
    
    private _getCursorPosition(lines: string[]): { success: boolean; position: Position} {
        let ret = { success: false, position: new Position(0, 0) };
        for (let i = 0; i < lines.length; i++) {
            let columnIdx = lines[i].indexOf('|');
            if (columnIdx >= 0) {
                ret.position = ret.position.setLocation(i, columnIdx);
                ret.success = true;
            }
        }

        return ret;
    }

    private _parse(t: TestObject): void {
        if (!this._setStartCursorPosition(t.start)) {
            this._isValid = false;
            return;
        }
        if (!this._setEndCursorPosition(t.end)) {
            this._isValid = false;
            return;
        }

        this._isValid = true;
    }

    public asVimInputText(): string[] {
        let ret = 'i' + this._testObject.start.join('\n').replace('|', '');
        return ret.split('');
    }

    public asVimOutputText(): string[] {
        let ret = this._testObject.end.slice(0);
        ret[this.endPosition.line] = ret[this.endPosition.line].replace('|', '');
        return ret;
    }

    /** Returns a sequence of Vim movement characters 'hjkl' as a string array
     * which will move the cursor to the start position given in the test. */
    public getKeyPressesToMoveToStartPosition(): string[] {
        let ret = '';
        let h = 0, j = 0, k = 0, l = 0;
        let linesToMove = this.startPosition.line - (this._testObject.start.length - 1);

        let cursorPosAfterEsc =
            this._testObject.start[this._testObject.start.length - 1].replace('|', '').length - 1;
        let numCharsInCursorStartLine =
            this._testObject.start[this.startPosition.line].replace('|', '').length - 1;
        let columnOnStartLine = Math.min(cursorPosAfterEsc, numCharsInCursorStartLine);
        let charactersToMove = this.startPosition.character - columnOnStartLine;

        if (linesToMove > 0) {
            ret += Array(linesToMove + 1).join('j');
        }   
        else if (linesToMove < 0) {
            ret += Array(Math.abs(linesToMove) + 1).join('k');
        }

        if (charactersToMove > 0) {
            ret += Array(charactersToMove + 1).join('l');
        }
        else if (charactersToMove < 0) {
            ret += Array(Math.abs(charactersToMove) + 1).join('h');
        }
        //console.log("ret is " + ret);
        return ret.split('');
    }
}

async function testIt(modeHandler: ModeHandler, testObj: TestObject): Promise<void> {
    let helper = new TestObjectHelper(testObj);

    // start:
    //
    await modeHandler.handleMultipleKeyEvents(helper.asVimInputText());
    
    // keysPressed:
    //
    await modeHandler.handleKeyEvent('<esc>');
    // move cursor to start position using 'hjkl'
    await modeHandler.handleMultipleKeyEvents(helper.getKeyPressesToMoveToStartPosition());

    // assumes key presses are single characters for now    
    await modeHandler.handleMultipleKeyEvents(testObj.keysPressed.split(''));
        
    // Check valid test object input
    assert(helper.isValid, "Missing '|' in test object.");
    
    // Check final cursor position
    //
    let actualPosition = Position.FromVSCodePosition(TextEditor.getSelection().start);
    let expectedPosition = helper.endPosition;
    assert.equal(actualPosition.line, expectedPosition.line, "Cursor LINE position is wrong.");
    assert.equal(actualPosition.character, expectedPosition.character, "Cursor CHARACTER position is wrong.");
    
    // end: check given end output is correct
    //
    assertEqualLines(helper.asVimOutputText());

    // endMode: check end mode is correct if given
    if (typeof testObj.endMode !== 'undefined') {
        let actualMode = ModeName[modeHandler.currentMode.name].toUpperCase();
        let expectedMode = ModeName[testObj.endMode].toUpperCase();
        assert.equal(actualMode, expectedMode, "Didn't enter correct mode.");    
    }
}


export { TestObject, testIt }