import {run} from '@ember/runloop';

// 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

export function replaceWithListSection(editor, matches, listTagName) {
    let {range, range: {head, head: {section}}} = editor;
    let text = section.textUntil(head);

    // we don't want to convert to a heading if the user has not just
    // finished typing the markdown (eg, they've made a previous
    // heading expansion then Cmd-Z'ed it to get the text back then
    // starts typing at the end of the heading)
    if (text !== matches[0]) {
        return;
    }

    if (section.isListItem) {
        if (section.parent.tagName === listTagName) {
            return;
        }

        // toggle all list items to the new list type
        editor.run((postEditor) => {
            let listRange = section.parent.toRange();
            let {post} = editor;

            range = range.extend(-(matches[0].length));
            postEditor.deleteRange(range);

            let cursorListItem;
            post.walkMarkerableSections(listRange, (listItem) => {
                let isCursorListItem = listItem === section;
                let changedListItem = postEditor.changeSectionTagName(listItem, listTagName);

                if (isCursorListItem) {
                    cursorListItem = changedListItem;
                }
            });

            postEditor.setRange(cursorListItem.headPosition().toRange());
        });

        return;
    }

    editor.run((postEditor) => {
        range = range.extend(-(matches[0].length));
        let position = postEditor.deleteRange(range);
        postEditor.setRange(position);
        postEditor.toggleSection(listTagName);
    });
}

function _addMarkdownMarkup(_this, editor, matches, markupStr) {
    let {range} = editor;
    let match = matches[0].trim();
    let mdChars = (match.length - matches[1].length) / 2;

    range = range.extend(-(match.length));

    editor.run((postEditor) => {
        let startPos = postEditor.deleteRange(range.head.toRange().extend(mdChars));
        let textRange = startPos.toRange().extend(matches[1].length);
        let markup = editor.builder.createMarkup(markupStr);
        postEditor.addMarkupToRange(textRange, markup);
        let endPos = postEditor.deleteRange(textRange.tail.toRange().extend(mdChars));
        postEditor.setRange(endPos.toRange());
    });

    // must be scheduled so that the toggle isn't reset automatically
    // by mobiledoc-kit re-setting state after the range is updated
    run.later(_this, function () {
        editor.toggleMarkup(markupStr);
    }, 10);
}

function _addNonReplacedMarkdownMarkup(_this, editor, matches, markupStr) {
    let {range} = editor;
    let match = matches[0].trim();
    range = range.extend(-(match.length));

    editor.run((postEditor) => {
        let markup = editor.builder.createMarkup(markupStr);
        postEditor.addMarkupToRange(range, markup);
        postEditor.setRange(range.tail.toRange());
    });

    // must be scheduled so that the toggle isn't reset automatically
    // by mobiledoc-kit re-setting state after the range is updated
    run.later(_this, function () {
        editor.toggleMarkup(markupStr);
    }, 10);
}

function _matchStrongStar(editor, text) {
    let matches = text.match(/(?:^|\s)\*\*([^\s*]+|[^\s*][^*]*[^\s])\*\*$/);
    if (matches) {
        _addMarkdownMarkup(this, editor, matches, 'strong');
    }
}

function _matchStrongUnderscore(editor, text) {
    let matches = text.match(/(?:^|\s)__([^\s_]+|[^\s_][^_]*[^\s])__$/);
    if (matches) {
        _addMarkdownMarkup(this, editor, matches, 'strong');
    }
}

function _matchEmStar(editor, text) {
    // (?:^|\s)     - match beginning of input or a starting space (don't capture)
    // \*           - match leading *
    // (            - start capturing group
    //   [^\s*]+    - match a stretch with no spaces or * chars
    //   |          - OR
    //   [^\s*]     - match a single non-space or * char    | this group will only match at
    //   [^*]*      - match zero or more non * chars        | least two chars so we need the
    //   [^\s]      - match a single non-space char         | [^\s*]+ to match single chars
    // )            - end capturing group
    // \*           - match trailing *
    //
    // input = " *foo*"
    // matches[0] = " *foo*"
    // matches[1] = "foo"
    let matches = text.match(/(?:^|\s)\*([^\s*]+|[^\s*][^*]*[^\s])\*$/);
    if (matches) {
        _addMarkdownMarkup(this, editor, matches, 'em');
    }
}

function _matchEmUnderscore(editor, text) {
    let matches = text.match(/(?:^|\s)_([^\s_]+|[^\s_][^_]*[^\s])_$/);
    if (matches) {
        _addMarkdownMarkup(this, editor, matches, 'em');
    }
}

function _matchSub(editor, text) {
    let matches = text.match(/(^|[^~])~([^\s~]+|[^\s~][^~]*[^\s~])~$/);
    if (matches) {
        // re-adjust the matches to remove the first matched char if it
        // exists, otherwise our length calculations are off. This is
        // different to other matchers because we match any char at the
        // beginning rather than a blank space and need to allow ~~ for
        // the strikethrough expansion
        let newMatches = [
            matches[1] ? matches[0].replace(matches[1], '').trim() : matches[0],
            matches[2]
        ];
        _addMarkdownMarkup(this, editor, newMatches, 'sub');
    }
}

function _matchStrikethrough(editor, text) {
    let matches = text.match(/(?:^|\s)~~([^\s~]+|[^\s~][^~]*[^\s])~~$/);
    if (matches) {
        _addMarkdownMarkup(this, editor, matches, 's');
    }
}

function _matchCode(editor, text) {
    let matches = text.match(/(?:^|\s)`([^\s`]+|[^\s`][^`]*[^\s`])`$/);
    if (matches) {
        _addMarkdownMarkup(this, editor, matches, 'code');
    }
}

function _matchSup(editor, text) {
    let matches = text.match(/\^([^\s^]+|[^\s^][^^]*[^\s^])\^$/);
    if (matches) {
        _addMarkdownMarkup(this, editor, matches, 'sup');
    }
}

function _matchLink(editor, text) {
    let {range} = editor;
    let matches = text.match(/(?:^|\s)\[([^\s\]]*|[^\s\]][^\]]*[^\s\]])\]\(([^\s)]+|[^\s)][^)]*[^\s)])\)/);
    if (matches) {
        let url = matches[2];
        let linkText = matches[1] || url;
        let hasLinkText = !!matches[1];
        let match = matches[0].trim();
        range = range.extend(-match.length);

        editor.run((postEditor) => {
            let startPos = postEditor.deleteRange(range.head.toRange().extend(hasLinkText ? 1 : 3));
            let textRange = startPos.toRange().extend(linkText.length);
            let a = postEditor.builder.createMarkup('a', {href: url});
            postEditor.addMarkupToRange(textRange, a);
            let remainingRange = textRange.tail.toRange().extend(hasLinkText ? (matches[2] || url).length + 3 : 1);
            let endPos = postEditor.deleteRange(remainingRange);
            postEditor.setRange(endPos.toRange());
        });

        // must be scheduled so that the toggle isn't reset automatically
        run.schedule('actions', this, function () {
            editor.toggleMarkup('a');
        });
    }
}

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

        // 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 registerDashTextExpansions(mobiledocEditor) {
    // --\s = en dash –
    // ---. = em dash —
    // separate to the grouped replacement functions because we're matching on
    // the trailing character which can be anything
    mobiledocEditor.onTextInput({
        name: 'hyphens',
        match: /---?.$/,
        run(editor) {
            let {range} = editor;

            let text = editor.range.head.section.textUntil(editor.range.head);

            // do not match if we're in code formatting
            if (editor.hasActiveMarkup('code') || text.match(/[^\s]?`[^\s]/)) {
                return;
            }

            let ndashMatch = text.match(/[^-]--(\s)$/);
            if (ndashMatch) {
                let match = ndashMatch[0];
                range = range.extend(-(match.length - 1));

                if (editor.detectMarkupInRange(range, 'code')) {
                    return;
                }

                return editor.run((postEditor) => {
                    let position = postEditor.deleteRange(range);
                    postEditor.insertText(position, `–${ndashMatch[1]}`);
                });
            }

            let mdashMatch = text.match(/---([^-])$/);
            if (mdashMatch) {
                let match = mdashMatch[0];
                range = range.extend(-(match.length));

                if (editor.detectMarkupInRange(range, 'code')) {
                    return;
                }

                return editor.run((postEditor) => {
                    let position = postEditor.deleteRange(range);
                    postEditor.insertText(position, `—${mdashMatch[1]}`);
                });
            }
        }
    });
}

function registerInlineMarkdownTextExpansions(mobiledocEditor) {
    // 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.

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

            switch (matches[0]) {
            case '*':
                _matchStrongStar(editor, text);
                _matchEmStar(editor, text);
                break;
            case '_':
                _matchStrongUnderscore(editor, text);
                _matchEmUnderscore(editor, text);
                break;
            case ')':
                _matchLink(editor, text);
                _matchImage(editor, text);
                break;
            case '~':
                _matchSub(editor, text);
                _matchStrikethrough(editor, text);
                break;
            case '`':
                _matchCode(editor, text);
                break;
            case '^':
                _matchSup(editor, text);
                break;
            }
        }
    });
}

export default function (mobiledocEditor, koenig) {
    /* block level markdown ------------------------------------------------- */

    mobiledocEditor.unregisterTextInputHandler('heading');
    mobiledocEditor.onTextInput({
        name: 'md_heading',
        match: /^(#{1,6}) /,
        run(editor, matches) {
            let hashes = matches[1];
            let headingTag = `h${hashes.length}`;
            let {range} = editor;
            let text = range.head.section.textUntil(range.head);

            // we don't want to convert to a heading if the user has not just
            // finished typing the markdown (eg, they've made a previous
            // heading expansion then Cmd-Z'ed it to get the text back then
            // starts typing at the end of the heading)
            if (text !== matches[0]) {
                return;
            }

            editor.run((postEditor) => {
                range = range.extend(-(matches[0].length));
                let position = postEditor.deleteRange(range);
                postEditor.setRange(position);

                // toggleHeaderSection will remove all formatting except links
                koenig.send('toggleHeaderSection', headingTag, postEditor);
            });
        }
    });

    mobiledocEditor.unregisterTextInputHandler('ul');
    mobiledocEditor.onTextInput({
        name: 'md_ul',
        match: /^\* |^- /,
        run(editor, matches) {
            replaceWithListSection(editor, matches, 'ul');
        }
    });

    mobiledocEditor.unregisterTextInputHandler('ol');
    mobiledocEditor.onTextInput({
        name: 'md_ol',
        match: /^1\.? /,
        run(editor, matches) {
            replaceWithListSection(editor, matches, 'ol');
        }
    });

    mobiledocEditor.onTextInput({
        name: 'md_blockquote',
        match: /^> /,
        run(editor, matches) {
            let {range} = editor;
            let {head, head: {section}} = range;
            let text = section.textUntil(head);

            // ensure cursor is at the end of the matched text so we don't
            // convert text the users wants to start with `> ` and that we're
            // not already on a blockquote section
            if (text === matches[0] && section.tagName !== 'blockquote') {
                editor.run((postEditor) => {
                    range = range.extend(-(matches[0].length));
                    let position = postEditor.deleteRange(range);
                    postEditor.setRange(position);

                    koenig.send('toggleSection', 'blockquote', postEditor);
                });
            }
        }
    });

    mobiledocEditor.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;
            }

            koenig.send('replaceWithCardSection', 'hr', section.toRange());
        }
    });

    mobiledocEditor.onTextInput({
        name: 'md_code',
        match: /^```([a-zA-Z0-9]*)(\s)$/,
        run(editor, matches) {
            let {range: {head, head: {section}}} = editor;
            let payload = {};

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

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

            if (matches[1]) {
                payload.language = matches[1];
            }

            if (matches[2] === '\n') {
                koenig.skipNewline();
            }

            koenig.send('replaceWithCardSection', 'code', section.toRange(), payload);
        }
    });

    /* non-markdown expansions -----------------------------------------------*/

    mobiledocEditor.onTextInput({
        name: 'paywall',
        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;
            }

            koenig.send('replaceWithCardSection', 'paywall', section.toRange());
        }
    });

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

    // must come after block expansions so that the smart hyphens expansion
    // doesn't break the divider card expansion
    registerDashTextExpansions(mobiledocEditor);
    registerInlineMarkdownTextExpansions(mobiledocEditor);
}

// TODO: reduce duplication
export function registerBasicInputTextExpansions(mobiledocEditor) {
    // unregister mobiledoc-kit's block-level text handlers
    mobiledocEditor.unregisterTextInputHandler('heading');
    mobiledocEditor.unregisterTextInputHandler('ul');
    mobiledocEditor.unregisterTextInputHandler('ol');

    registerDashTextExpansions(mobiledocEditor);
    registerInlineMarkdownTextExpansions(mobiledocEditor);
}

// TODO: reduce duplication
export function registerBasicTextareaTextExpansions(mobiledocEditor, koenig) {
    // unregister mobiledoc-kit's block-level text handlers
    mobiledocEditor.unregisterTextInputHandler('heading');

    mobiledocEditor.unregisterTextInputHandler('ul');
    mobiledocEditor.onTextInput({
        name: 'md_ul',
        match: /^\* |^- /,
        run(editor, matches) {
            replaceWithListSection(editor, matches, 'ul');
        }
    });

    mobiledocEditor.unregisterTextInputHandler('ol');
    mobiledocEditor.onTextInput({
        name: 'md_ol',
        match: /^1\.? /,
        run(editor, matches) {
            replaceWithListSection(editor, matches, 'ol');
        }
    });

    // must come after block expansions so that the smart hyphens expansion
    // doesn't break the divider card expansion
    registerDashTextExpansions(mobiledocEditor);
    registerInlineMarkdownTextExpansions(mobiledocEditor);
}

// TODO: reduce duplication
export function registerTextReplacementTextExpansions(mobiledocEditor, koenig) {
    // unregister mobiledoc-kit's block-level text handlers
    mobiledocEditor.unregisterTextInputHandler('heading');

    mobiledocEditor.unregisterTextInputHandler('ul');
    mobiledocEditor.onTextInput({
        name: 'md_ul',
        match: /^\* |^- /,
        run(editor, matches) {
            replaceWithListSection(editor, matches, 'ul');
        }
    });

    mobiledocEditor.unregisterTextInputHandler('ol');
    mobiledocEditor.onTextInput({
        name: 'md_ol',
        match: /^1\.? /,
        run(editor, matches) {
            replaceWithListSection(editor, matches, 'ol');
        }
    });

    mobiledocEditor.onTextInput({
        name: 'md_blockquote',
        match: /^> /,
        run(editor, matches) {
            let {range} = editor;
            let {head, head: {section}} = range;
            let text = section.textUntil(head);

            // ensure cursor is at the end of the matched text so we don't
            // convert text the users wants to start with `> ` and that we're
            // not already on a blockquote section
            if (text === matches[0] && section.tagName !== 'blockquote') {
                editor.run((postEditor) => {
                    range = range.extend(-(matches[0].length));
                    let position = postEditor.deleteRange(range);
                    postEditor.setRange(position);

                    koenig.send('toggleSection', 'blockquote', postEditor);
                });
            }
        }
    });

    // as per registerInlineMarkdownTextExpansions but without ` for code and image matches
    mobiledocEditor.onTextInput({
        name: 'inline_markdown',
        match: /[*_)~^]$/,
        run(editor, matches) {
            let text = editor.range.head.section.textUntil(editor.range.head);

            switch (matches[0]) {
            case '*':
                _matchStrongStar(editor, text);
                _matchEmStar(editor, text);
                break;
            case '_':
                _matchStrongUnderscore(editor, text);
                _matchEmUnderscore(editor, text);
                break;
            case ')':
                _matchLink(editor, text);
                break;
            case '~':
                _matchSub(editor, text);
                _matchStrikethrough(editor, text);
                break;
            case '^':
                _matchSup(editor, text);
                break;
            }
        }
    });

    mobiledocEditor.onTextInput({
        name: 'text_replacement',
        match: /\}$/,
        run(editor) {
            let text = editor.range.head.section.textUntil(editor.range.head);

            let match = text.match(/(?:^|\s)\{([^\s{}]+|[^\s{}][^{}]*[^\s{}])\}$/);
            if (match) {
                _addNonReplacedMarkdownMarkup(this, editor, match, 'code');
            }
        }
    });
}