import {EditorView, gutter, keymap, lineNumbers} from "@codemirror/view"
import {Compartment, EditorState, Facet, SelectionRange} from "@codemirror/state"
import {indentLess} from "@codemirror/commands";

EditorView.theme({}, {dark: true})

let editorsjs = []
let editorsParentdom = document.getElementById('editors')
let allEditorsdom = document.querySelectorAll('#editors > .editor')
let firstEditordom = allEditorsdom[0]

const txtFacet = Facet.define({
    combine(values) {
        return values[0]
    }
})
let indentSize = new Compartment, wrapMode = new Compartment, indentType = new Compartment

const newEditor = (dom, value = '') => {
    let editor = new EditorView({
        doc: value,
        parent: dom,
        extensions: [
            lineNumbers(), gutter({class: "cm-mygutter"}),
            keymap.of([{key: "Tab", run: customIndentMore, shift: indentLess}]),
            indentSize.of(EditorState.tabSize.of(2)),
            wrapMode.of([]),
            indentType.of(txtFacet.of("space")),
        ]
    })

    dom.querySelector('.editor-indent-type').onchange = (e) => {
        let newTabType = e.target.value
        setIndentType(editor, !['tab', 'space'].includes(newTabType) ? 'space' : newTabType)
    }

    dom.querySelector('.editor-indent-size').onchange = (e) => {
        let newTabSize = parseInt(e.target.value)
        setIndentSize(editor, ![2, 4, 8].includes(newTabSize) ? 2 : newTabSize)
    }

    dom.querySelector('.editor-wrap-mode').onchange = (e) => {
        let newWrapMode = e.target.value
        setLineWrapping(editor, newWrapMode === 'soft')
    }

    dom.addEventListener("drop", (e) => {
        e.preventDefault(); // prevent the browser from opening the dropped file
        e.target.closest('.editor').querySelector('input.form-filename').value = e.dataTransfer.files[0].name
    });

    // remove editor on delete
    let deleteBtns = dom.querySelector('button.delete-file')
    if (deleteBtns !== null) {
        deleteBtns.onclick = () => {
            editorsjs.splice(editorsjs.indexOf(editor), 1);
            dom.remove()
        }
    }

    editor.dom.addEventListener("input", function inputConfirmLeave() {
        if (!editor.inView) return; // skip events outside the viewport

        editor.dom.removeEventListener("input", inputConfirmLeave);
        window.onbeforeunload = () => {
            return 'Are you sure you want to quit?';
        }
    });

    return editor;
}

function getIndentation(state) {
    if (indentType.get(state).value === 'tab') {
        return '\t';
    }
    return ' '.repeat(indentSize.get(state).value);
}

function customIndentMore({state, dispatch}) {
    let indentation = getIndentation(state)
    dispatch({
        ...state.update(changeBySelectedLine(state, (line, changes) => {
            changes.push({from: state.selection.ranges[0].from, insert: indentation})
        })), selection: {
            anchor: state.selection.ranges[0].from + indentation.length,
            head: state.selection.ranges[0].from + indentation.length,
        }
    })
    return true
}

function changeBySelectedLine(state, f) {
    let atLine = -1
    return state.changeByRange(range => {
        let changes = []
        for (let line = state.doc.lineAt(range.from); ;) {
            if (line.number > atLine) {
                f(line, changes)
                atLine = line.number
            }
            if (range.to <= line.to) break
            line = state.doc.lineAt(line.number + 1)
        }
        let changeSet = state.changes(changes)
        return {changes, range: new SelectionRange(changeSet.mapPos(range.anchor, 1), changeSet.mapPos(range.head, 1))}
    })
}

function setIndentType(view, type) {
    view.dispatch({effects: indentType.reconfigure(txtFacet.of(type))})
}

function setIndentSize(view, size) {
    view.dispatch({effects: indentSize.reconfigure(EditorState.tabSize.of(size))})
}

function setLineWrapping(view, enable) {
    if (enable) {
        view.dispatch({effects: wrapMode.reconfigure(EditorView.lineWrapping)})
    } else {
        view.dispatch({effects: wrapMode.reconfigure([])})
    }
}

let arr = [...allEditorsdom]
arr.forEach(el => {
    // in case we edit the gist contents
    let currEditor = newEditor(el, el.querySelector('.form-filecontent').value)
    editorsjs.push(currEditor)
})

document.getElementById('add-file').onclick = () => {
    let newEditorDom = firstEditordom.cloneNode(true)

    // reset the filename of the new cloned element
    newEditorDom.querySelector('input[name="name"]').value = ""

    // removing the previous codemirror editor
    let newEditorDomCM = newEditorDom.querySelector('.cm-editor')
    newEditorDomCM.remove()

    // creating the new codemirror editor and append it in the editor div
    editorsjs.push(newEditor(newEditorDom))
    editorsParentdom.append(newEditorDom)
}

document.querySelector('form#create').onsubmit = () => {
    let j = 0
    document.querySelectorAll('.form-filecontent').forEach((e) => {
        e.value = encodeURIComponent(editorsjs[j++].state.doc.toString())
    })
}

document.onsubmit = () => {
    window.onbeforeunload = null;
}