wiki.yml

name: Wiki Alert

# The alert is not sent for all wiki changes:
#
# The "gollum" event only fires whenever the wiki HEAD changes, only considering the
# changes in the latest commit, and only if the pages were created or modified, not
# deleted. But pushing multiple commits is limited to GitHub collaborators (or above).

on: gollum

jobs:
  notify:
    runs-on: ubuntu-latest
    steps:
      - name: Secret Check
        id: secret
        run: echo "empty=${{secrets.WIKI_WEBHOOK == ''}}" >> $GITHUB_OUTPUT

      - name: Checkout
        if: steps.secret.outputs.empty == 'false'
        uses: actions/checkout@v6
        with:
          repository: ${{github.repository}}.wiki

      - name: Send Webhook
        if: steps.secret.outputs.empty == 'false'
        uses: actions/github-script@v9
        with:
          script: |
            // https://docs.discord.com/developers/resources/message#embed-object-embed-limits
            const limits = {
                message: 6000,
                description: 4096,
                embeds: 10,
                fields: 25,
            };
            const messageConfig = {
                username: "Wiki Updates",
                avatar: "https://files.jasperlorelai.eu/magicspells/images/webhook_icon.png"
            };
            
            /**
             * @typedef {Object} EmbedFooter
             * @property {string=} text
             */
            
            /**
             * @typedef {Object} EmbedAuthor
             * @property {string=} name
             * @property {string=} url
             * @property {string=} url_icon
             */
            
            /**
             * @typedef {Object} EmbedField
             * @property {string} name
             * @property {string} value
             * @property {boolean=} inline
             */
            
            /**
             * @typedef {Object} Embed
             * @property {string=} title
             * @property {string=} url
             * @property {string=} description
             * @property {EmbedFooter=} footer
             * @property {EmbedAuthor=} author
             * @property {EmbedField[]=} fields
             */
            
            if (!context.payload.pages?.length) {
                core.info("No pages in payload.");
                return;
            }
            
            // Commit sha/message will be shared across pages in a "gollum" event.
            const {sha} = context.payload.pages[0];
            const {stdout} = await exec.getExecOutput(`git log -1 --pretty=format:"%B" ${sha}`);
            let description = "";
            for (const line of stdout.trim().split("\n")) {
                description += "\n> " + line;
            }
            if (description.length > limits.description) {
                description = description.substring(0, limits.description - 3) + "...";
            }
            
            // Array of batched 10 max embeds per element.
            /** @type {Array<Embed[]>} */
            const batches = [];
            
            for (const {title, html_url} of context.payload.pages) {
                /** @type {EmbedField} */
                const field = {
                    inline: true,
                    name: title,
                    value: `-# [Page](${html_url}/${sha}) • [Changes](${html_url}/_compare/${sha})`
                };
            
                let messageSize = field.name.length + field.value.length;
                if (batches.length) {
                    for (const embed of batches.at(-1)) {
                        messageSize += (embed.title?.length || 0) +
                            (embed.description?.length || 0) +
                            (embed.footer?.text?.length || 0) +
                            (embed.author?.name?.length || 0);

                        if (!embed.fields?.length) continue;
                        for (const field of embed.fields) {
                            messageSize += field.name.length + field.value.length;
                        }
                    }
                }
            
                const needsNewBatch = !batches.length ||
                    batches.at(-1).length >= limits.embeds ||
                    messageSize >= limits.message;
            
                if (needsNewBatch) batches.push([{
                    title: "Pages Changed",
                    url: `${html_url.substring(0, html_url.lastIndexOf("/"))}/_compare/${sha}`,
                    description,
                    author: {
                        name: "Edited by: " + context.payload.sender.login,
                        url: context.payload.sender.html_url,
                        icon_url: context.payload.sender.avatar_url,
                    },
                    fields: []
                }]);
            
                const needsNewEmbed = batches.at(-1).at(-1).fields.length >= limits.fields;
                if (needsNewEmbed) batches.at(-1).push({fields: []});
            
                batches.at(-1).at(-1).fields.push(field);
            }
            
            for (const embeds of batches) {
                const message = {
                    username: messageConfig.username,
                    avatar_url: messageConfig.avatar,
                    embeds
                };
                await fetch("${{secrets.WIKI_WEBHOOK}}", {
                    method: "POST",
                    headers: {"Content-Type": "application/json"},
                    body: JSON.stringify(message)
                }).catch(error => core.setFailed(error.message));
            }