import {
    replaceWithHeaderSection,
    replaceWithListSection
} from 'mobiledoc-kit/editor/text-input-handlers';

// Text expansions watch text entry events and will look for matches, replacing
// the matches with additional markup, atoms, or cards
// https://github.com/bustlelabs/mobiledoc-kit#responding-to-text-input

// TODO: this was copied from our old Koenig editor, it could do with some
// comments, cleanup, and refactoring

export default function (editor) {
    // We don't want to run all our content rules on every text entry event,
    // instead we check to see if this text entry event could match a content
    // rule, and only then run the rules. Right now we only want to match
    // content ending with *, _, ), ~, and `. This could increase as we support
    // more markdown.

    editor.onTextInput({
        name: 'inline_markdown',
        match: /[*_)~`]$/,
        run(postEditor, matches) {
            let text = postEditor.range.head.section.textUntil(postEditor.range.head);

            switch (matches[0]) {
            case '*':
                matchStrongStar(postEditor, text);
                matchEmStar(postEditor, text);
                break;
            case '_':
                matchStrongUnderscore(postEditor, text);
                matchEmUnderscore(postEditor, text);
                break;
            case ')':
                matchLink(postEditor, text);
                matchImage(postEditor, text);
                break;
            case '~':
                matchStrikethrough(postEditor, text);
                break;
            case '`':
                matchCode(postEditor, text);
                break;
            }
        }
    });

    /* block level markdown ------------------------------------------------- */

    // mobiledoc-kit has `* ` already built-in so we only need to add `- `
    editor.onTextInput({
        name: 'md_ul',
        match: /^- $/,
        run(editor) {
            replaceWithListSection(editor, 'ul');
        }
    });

    editor.onTextInput({
        name: 'md_blockquote',
        match: /^> $/,
        run(editor) {
            replaceWithHeaderSection(editor, 'blockquote');
        }
    });

    editor.onTextInput({
        name: 'md_hr',
        match: /^---$/,
        run(editor) {
            let {range: {head, head: {section}}} = editor;

            // Skip if cursor is not at end of section
            if (!head.isTail()) {
                return;
            }

            // Skip if section is a list item
            if (section.isListItem) {
                return;
            }

            editor.run((postEditor) => {
                let card = postEditor.builder.createCardSection('hr');
                let needsTrailingParagraph = !section.next;

                postEditor.replaceSection(section, card);

                // add an empty paragraph after if necessary so writing can continue
                if (needsTrailingParagraph) {
                    let newSection = postEditor.builder.createMarkupSection('p');
                    postEditor.insertSectionAtEnd(newSection);
                    postEditor.setRange(newSection.tailPosition());
                }
            });
        }
    });

    /* inline markdown ------------------------------------------------------ */

    function matchStrongStar(editor, text) {
        let {range} = editor;
        let matches = text.match(/\*\*(.+?)\*\*$/);
        if (matches) {
            range = range.extend(-(matches[0].length));
            editor.run((postEditor) => {
                let position = postEditor.deleteRange(range);
                let bold = postEditor.builder.createMarkup('strong');
                let nextPosition = postEditor.insertTextWithMarkup(position, matches[1], [bold]);
                postEditor.insertTextWithMarkup(nextPosition, ' ', []);
            });
        }
    }

    function matchStrongUnderscore(editor, text) {
        let {range} = editor;
        let matches = text.match(/__(.+?)__$/);
        if (matches) {
            range = range.extend(-(matches[0].length));
            editor.run((postEditor) => {
                let position = postEditor.deleteRange(range);
                let bold = postEditor.builder.createMarkup('strong');
                let nextPosition = postEditor.insertTextWithMarkup(position, matches[1], [bold]);
                postEditor.insertTextWithMarkup(nextPosition, ' ', []);
            });
        }
    }

    function matchEmStar(editor, text) {
        let {range} = editor;
        let matches = text.match(/(^|[^*])\*([^*].*?)\*$/);
        if (matches) {
            let match = matches[0][0] === '*' ? matches[0] : matches[0].substr(1);
            range = range.extend(-(match.length));
            editor.run((postEditor) => {
                let position = postEditor.deleteRange(range);
                let em = postEditor.builder.createMarkup('em');
                let nextPosition = postEditor.insertTextWithMarkup(position, matches[2], [em]);
                postEditor.insertTextWithMarkup(nextPosition, ' ', []);
            });
        }
    }

    function matchEmUnderscore(editor, text) {
        let {range} = editor;
        let matches = text.match(/(^|[^_])_([^_].+?)_$/);
        if (matches) {
            let match = matches[0][0] === '_' ? matches[0] : matches[0].substr(1);
            range = range.extend(-(match.length));
            editor.run((postEditor) => {
                let position = postEditor.deleteRange(range);
                let em = postEditor.builder.createMarkup('em');
                let nextPosition = postEditor.insertTextWithMarkup(position, matches[2], [em]);
                postEditor.insertTextWithMarkup(nextPosition, ' ', []);
            });
        }
    }

    function matchLink(editor, text) {
        let {range} = editor;
        let matches = text.match(/(^|[^!])\[(.*?)\]\((.*?)\)$/);
        if (matches) {
            let url = matches[3];
            let text = matches[2];
            let match = matches[0][0] === '[' ? matches[0] : matches[0].substr(1);
            range = range.extend(-match.length);
            editor.run((postEditor) => {
                let position = postEditor.deleteRange(range);
                let a = postEditor.builder.createMarkup('a', {href: url});
                let nextPosition = postEditor.insertTextWithMarkup(position, text, [a]);
                postEditor.insertTextWithMarkup(nextPosition, ' ', []); // insert the un-marked-up space
            });
        }
    }

    function matchImage(editor, text) {
        let matches = text.match(/^!\[(.*?)\]\((.*?)\)$/);
        if (matches) {
            let {range: {head, head: {section}}} = editor;
            let src = matches[2];
            let alt = matches[1];

            // skip if cursor is not at end of section
            if (!head.isTail()) {
                return;
            }

            // mobiledoc lists don't support cards
            if (section.isListItem) {
                return;
            }

            editor.run((postEditor) => {
                let card = postEditor.builder.createCardSection('image', {src, alt});
                // need to check the section before replacing else it will always
                // add a trailing paragraph
                let needsTrailingParagraph = !section.next;

                editor.range.extend(-(matches[0].length));
                postEditor.replaceSection(editor.range.headSection, card);

                if (needsTrailingParagraph) {
                    let newSection = editor.builder.createMarkupSection('p');
                    postEditor.insertSectionAtEnd(newSection);
                    postEditor.setRange(newSection.tailPosition());
                }
            });
        }
    }

    function matchStrikethrough(editor, text) {
        let {range} = editor;
        let matches = text.match(/~(.+?)~$/);
        if (matches) {
            range = range.extend(-(matches[0].length));
            editor.run((postEditor) => {
                let position = postEditor.deleteRange(range);
                let s = postEditor.builder.createMarkup('s');
                let nextPosition = postEditor.insertTextWithMarkup(position, matches[1], [s]);
                postEditor.insertTextWithMarkup(nextPosition, ' ', []); // insert the un-marked-up space
            });
        }
    }

    function matchCode(editor, text) {
        let {range} = editor;
        let matches = text.match(/`(.+?)`/);
        if (matches) {
            range = range.extend(-(matches[0].length));
            editor.run((postEditor) => {
                let position = postEditor.deleteRange(range);
                let code = postEditor.builder.createMarkup('code');
                let nextPosition = postEditor.insertTextWithMarkup(position, matches[1], [code]);
                postEditor.insertTextWithMarkup(nextPosition, ' ', []); // insert the un-marked-up space
            });
        }
    }
}