import { PullMeta, PullRef } from "./domain/model.ts";

const start = "<!-- stack:links:start -->";

const end = "<!-- stack:links:end -->";

const heading = "### [Stack](https://github.com/kitlangton/stack)";

const format = (

branch: string,

prs: ReadonlyMap<string, PullRef>,

metas: ReadonlyMap<string, PullMeta>,

) => {

const pr = prs.get(branch);

if (pr) return `#${pr.number}`;

const meta = metas.get(branch);

if (meta) return `#${meta.number}`;

return `\`${branch}\``;

};

const completedLines = (

body: string,

liveKeys: ReadonlySet<string>,

completedKeys: ReadonlySet<string>,

) => {

const prior = body.match(new RegExp(`${start}([\\s\\S]*?)${end}`))?.[1];

if (!prior) return [];

return prior

.split("\n")

.map((line) => line.trim())

.filter((line) => line.startsWith("- [") || /^\d+\.\s+/.test(line))

.flatMap((line) => {

const checked = line.startsWith("- [x]");

const numbered = /^\d+\.\s+/.test(line);

const branch = line.match(/`([^`]+)`/)?.[1] ?? null;

const pr = line.match(/#\d+/)?.[0] ?? null;

const key = branch ?? pr;

if (!key || liveKeys.has(key)) return [];

if (completedKeys.size > 0 && !numbered && !checked && !completedKeys.has(key)) {

return [];

}

if (completedKeys.size === 0 && line.startsWith("- [") && !checked) {

return [];

}

return [

line

.replace(/^- \[[ x]\]\s+/, "")

.replace(/^\d+\.\s+/, "")

.replaceAll("**", "")

.replace(/(#\d+)\s+`[^`]+`/g, "$1")

.replace(/\s*(?:←|👈) current$/, ""),

];

});

};

export const render = (opts: {

readonly pulls: ReadonlyArray<PullRef>;

readonly metas: ReadonlyMap<string, PullMeta>;

readonly chain: ReadonlyArray<string>;

readonly completed?: ReadonlySet<string>;

readonly branch: string;

readonly previous: string;

}) => {

const prs = new Map(opts.pulls.map((pull) => [String(pull.head), pull]));

const chain = opts.chain;

const liveKeys = new Set(

chain.flatMap((branch) => {

const pr = prs.get(branch) ?? opts.metas.get(branch) ?? null;

return pr ? [branch, `#${pr.number}`] : [branch];

}),

);

const line = (name: string) => {

const head = format(name, prs, opts.metas);

if (name === opts.branch) return `**${head}** 👈 current`;

return head;

};

const items = [

...completedLines(opts.previous, liveKeys, opts.completed ?? new Set()),

...chain.map(line),

];

return [start, heading, "", ...items.map((item, index) => `${index + 1}. ${item}`), end].join(

"\n",

);

};

export const splice = (body: string, next: string) => {

const cleaned = body.replace(new RegExp(`${start}[\\s\\S]*?${end}\n*`, "g"), "").trimEnd();

return cleaned ? `${cleaned}\n\n${next}` : next;

};