import express from "express";
import path from "path";
import { fileURLToPath } from "url";
import fs from "fs/promises";

const app = express();
const PORT = process.env.PORT || 3001;
const CACHE_TTL_MS = Number(process.env.CACHE_TTL_MS || 10 * 60 * 1000);

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);
const rootDir = path.resolve(__dirname, "..");
const distDir = path.join(rootDir, "dist");
const reposFile = path.join(__dirname, "repos.json");

const cache = new Map();

function parseRepoEntry(entry) {
    // support legacy string entries and object entries
    if (typeof entry === "string") {
        return {
            provider: "github",
            ownerRepo: entry,
            baseUrl: "https://github.com"
        };
    }
    const provider = (entry.provider || "github").toLowerCase();
    const ownerRepo = entry.repo || entry.ownerRepo || "";
    const baseUrl = entry.baseUrl || (provider === "github" ? "https://github.com" : entry.baseUrl || "");
    return { provider, ownerRepo, baseUrl };
}

async function readRepos() {
    const content = await fs.readFile(reposFile, "utf-8");
    const parsed = JSON.parse(content);
    return Array.isArray(parsed) ? parsed : [];
}

function getCached(key) {
    const entry = cache.get(key);
    if (!entry) return null;
    if (Date.now() > entry.expiresAt) {
        cache.delete(key);
        return null;
    }
    return entry.value;
}

function setCached(key, value) {
    cache.set(key, { value, expiresAt: Date.now() + CACHE_TTL_MS });
}

async function fetchJson(url, cacheKey, opts = {}) {
    const cached = getCached(cacheKey);
    if (cached) return cached;
    const headers = {
        "User-Agent": "siti-plugin-repo",
        Accept: "application/json"
    };
    // prefer GitHub API accept header when talking to github.com/api
    if (!opts.provider || opts.provider === "github") {
        headers.Accept = "application/vnd.github+json";
    }

    const response = await fetch(url, { headers });
    if (!response.ok) {
        throw new Error(`${opts.provider || "git"} request failed for ${url}`);
    }
    const data = await response.json().catch(async () => {
        // attempt to read text for non-json responses
        const text = await response.text();
        try {
            return JSON.parse(text);
        } catch {
            return null;
        }
    });
    setCached(cacheKey, data);
    return data;
}

async function fetchRepo(entry) {
    const { provider, ownerRepo, baseUrl } = parseRepoEntry(entry);
    const cacheKey = `repo:${provider}:${ownerRepo}`;
    const cached = getCached(cacheKey);
    if (cached) return cached;

    let data;
    if (provider === "gitea") {
        const url = `${baseUrl.replace(/\/$/, "")}/api/v1/repos/${ownerRepo}`;
        data = await fetchJson(url, `repo-raw:${provider}:${ownerRepo}`, { provider });
        const mapped = {
            fullName: data.full_name || `${ownerRepo}`,
            name: data.name || ownerRepo.split("/")[1] || ownerRepo,
            description: data.description || null,
            repoUrl: `${baseUrl.replace(/\/$/, "")}/${ownerRepo}`,
            defaultBranch: data.default_branch || data.default_branch || "main",
            stars: data.stargazers_count || data.watchers || 0,
            forks: data.forks_count || data.forks || 0,
            issues: data.open_issues_count || 0,
            updatedAt: data.updated_at || data.updated || null,
            topics: data.topics || []
        };
        setCached(cacheKey, mapped);
        return mapped;
    }

    // default: github
    data = await fetchJson(`https://api.github.com/repos/${ownerRepo}`, `repo-raw:github:${ownerRepo}`, { provider: "github" });
    const mapped = {
        fullName: data.full_name,
        name: data.name,
        description: data.description,
        repoUrl: data.html_url,
        defaultBranch: data.default_branch,
        stars: data.stargazers_count,
        forks: data.forks_count,
        issues: data.open_issues_count,
        updatedAt: data.updated_at,
        topics: data.topics || []
    };
    setCached(cacheKey, mapped);
    return mapped;
}

async function fetchManifest(entry, defaultBranch) {
    const { provider, ownerRepo, baseUrl } = parseRepoEntry(entry);
    const cacheKey = `manifest:${provider}:${ownerRepo}`;
    const cached = getCached(cacheKey);
    if (cached) return cached;

    const branches = [defaultBranch, "main", "master"].filter(Boolean);
    const [owner, repo] = ownerRepo.split("/");
    for (const branch of branches) {
        let url;
        if (provider === "gitea") {
            url = `${baseUrl.replace(/\/$/, "")}/repos/${owner}/${repo}/raw/${branch}/manifest.json`;
        } else {
            url = `https://raw.githubusercontent.com/${ownerRepo}/${branch}/manifest.json`;
        }
        const response = await fetch(url, { headers: { "User-Agent": "siti-plugin-repo" } });
        if (response.ok) {
            const manifest = await response.json().catch(() => null);
            setCached(cacheKey, manifest);
            return manifest;
        }
    }
    return null;
}

async function fetchReleases(entry) {
    const { provider, ownerRepo, baseUrl } = parseRepoEntry(entry);
    if (provider === "gitea") {
        const url = `${baseUrl.replace(/\/$/, "")}/api/v1/repos/${ownerRepo}/releases?limit=5`;
        const data = await fetchJson(url, `releases:${provider}:${ownerRepo}`, { provider });
        return Array.isArray(data)
            ? data.map((release) => ({
                tag: release.tag_name || release.name,
                name: release.name || release.tag_name,
                url: release.html_url || `${baseUrl.replace(/\/$/, "")}/${ownerRepo}/releases`,
                publishedAt: release.published_at || release.created_at
            }))
            : [];
    }

    const data = await fetchJson(
        `https://api.github.com/repos/${ownerRepo}/releases?per_page=5`,
        `releases:github:${ownerRepo}`,
        { provider: "github" }
    );
    return Array.isArray(data)
        ? data.map((release) => ({
            tag: release.tag_name,
            name: release.name || release.tag_name,
            url: release.html_url,
            publishedAt: release.published_at
        }))
        : [];
}

async function fetchCommits(entry) {
    const { provider, ownerRepo, baseUrl } = parseRepoEntry(entry);
    if (provider === "gitea") {
        const url = `${baseUrl.replace(/\/$/, "")}/api/v1/repos/${ownerRepo}/commits?limit=5`;
        const data = await fetchJson(url, `commits:${provider}:${ownerRepo}`, { provider });
        return Array.isArray(data)
            ? data.map((commit) => ({
                sha: commit.sha,
                message: commit.commit?.message || commit.message,
                author: commit.commit?.author?.name || commit.author?.name,
                date: commit.commit?.author?.date || commit.author?.date,
                url: commit.html_url || `${baseUrl.replace(/\/$/, "")}/${ownerRepo}/commit/${commit.sha}`
            }))
            : [];
    }

    const data = await fetchJson(
        `https://api.github.com/repos/${ownerRepo}/commits?per_page=5`,
        `commits:github:${ownerRepo}`,
        { provider: "github" }
    );
    return Array.isArray(data)
        ? data.map((commit) => ({
            sha: commit.sha,
            message: commit.commit?.message,
            author: commit.commit?.author?.name,
            date: commit.commit?.author?.date,
            url: commit.html_url
        }))
        : [];
}

app.get("/api/plugins", async (_req, res) => {
    try {
        const repos = await readRepos();
        const results = await Promise.all(
            repos.map(async (repo) => {
                try {
                    const info = await fetchRepo(repo);
                    const manifest = await fetchManifest(repo, info.defaultBranch || info.default_branch);
                    return { ...info, manifest };
                } catch {
                    const parsed = parseRepoEntry(repo);
                    return {
                        fullName: parsed.ownerRepo,
                        name: parsed.ownerRepo.split("/")[1] || parsed.ownerRepo,
                        description: "Kon gegevens niet ophalen.",
                        repoUrl: parsed.provider === "gitea" ? `${parsed.baseUrl.replace(/\/$/, "")}/${parsed.ownerRepo}` : `https://github.com/${parsed.ownerRepo}`,
                        stars: 0,
                        forks: 0,
                        issues: 0,
                        updatedAt: null,
                        topics: [],
                        manifest: null
                    };
                }
            })
        );

        res.json({
            count: results.length,
            updatedAt: new Date().toISOString(),
            items: results
        });
    } catch (error) {
        res.status(500).json({ error: "Kon plugins niet laden." });
    }
});

app.get("/api/plugins/:owner/:repo", async (req, res) => {
    const ownerRepo = `${req.params.owner}/${req.params.repo}`;
    try {
        const provider = (req.query.provider || "github").toLowerCase();
        const baseUrl = req.query.baseUrl || (provider === "github" ? "https://github.com" : "");
        const entry = provider === "github" ? ownerRepo : { provider, repo: ownerRepo, baseUrl };

        const info = await fetchRepo(entry);
        const [manifest, releases, commits] = await Promise.all([
            fetchManifest(entry, info.defaultBranch).catch(() => null),
            fetchReleases(entry).catch(() => []),
            fetchCommits(entry).catch(() => [])
        ]);

        res.json({
            ...info,
            manifest,
            releases,
            commits
        });
    } catch (error) {
        res.status(500).json({ error: "Kon plugin details niet laden." });
    }
});

app.use(express.static(distDir));
app.get("*", (_req, res) => {
    res.sendFile(path.join(distDir, "index.html"));
});

const HOST = process.env.HOST || "::";
app.listen(PORT, HOST, () => {
    console.log(`Server draait op http://${HOST}:${PORT}`);
});