import { randomUUID } from "node:crypto";
import type { EvidenceRecord } from "@siax/c0py-types";

export interface CapturedPage {
  finalUrl: string;
  status: number;
  contentType: string | null;
  title: string | null;
  description: string | null;
  lang: string | null;
  charset: string | null;
  viewportMeta: string | null;
  domCounts: Record<string, number>;
  stylesheets: string[];
  images: string[];
  computedStyle: Record<string, Record<string, string | null>>;
  networkRequests: { url: string; method: string; resourceType: string; status: number | null }[];
  accessibilityTree: {
    role: string | null;
    name: string | null;
    value: string | null;
    children?: unknown[];
  } | null;
  har: {
    entries: { url: string; method: string; status: number; mimeType: string | null; size: number | null }[];
    entryCount: number;
  } | null;
  screenshotBase64: string | null;
}

export interface CaptureEvidence {
  evidence: EvidenceRecord[];
  summary: {
    url: string;
    status: number;
    title: string | null;
    domElementCount: number;
    stylesheetCount: number;
    imageCount: number;
    networkRequestCount: number;
    screenshotCaptured: boolean;
  };
}

export const DEFAULT_PROFILE_ID = "c0py-default-public";
export const DEFAULT_VIEWPORT = { width: 1280, height: 800, deviceScaleFactor: 1 };

function record<T>(
  targetId: string,
  route: string,
  kind: EvidenceRecord["kind"],
  payload: T,
  tool: string,
): EvidenceRecord<T> {
  return {
    id: randomUUID(),
    targetId,
    kind,
    route,
    capturedAt: new Date().toISOString(),
    method: "deterministic-browser-capture",
    confidence: "measured",
    captureProfileId: DEFAULT_PROFILE_ID,
    viewport: DEFAULT_VIEWPORT,
    source: { tool, toolVersion: process.env.CAPTURE_TOOL_VERSION ?? "unknown" },
    payload,
  };
}

// Pure builder — unit-testable without a browser.
export function buildEvidence(targetId: string, page: CapturedPage): CaptureEvidence {
  const tool = "playwright-core+chromium";
  const evidence: EvidenceRecord[] = [
    record(targetId, page.finalUrl, "runtime-html", {
      finalUrl: page.finalUrl,
      status: page.status,
      contentType: page.contentType,
      title: page.title,
      description: page.description,
      lang: page.lang,
      charset: page.charset,
      viewportMeta: page.viewportMeta,
    }, tool),
    record(targetId, page.finalUrl, "dom", {
      counts: page.domCounts,
    }, tool),
    record(targetId, page.finalUrl, "computed-style", page.computedStyle, tool),
    record(targetId, page.finalUrl, "stylesheet", {
      stylesheets: page.stylesheets,
    }, tool),
    record(targetId, page.finalUrl, "asset", {
      images: page.images,
    }, tool),
    record(targetId, page.finalUrl, "network-request", {
      requests: page.networkRequests,
    }, tool),
  ];
  if (page.accessibilityTree) {
    evidence.push(
      record(targetId, page.finalUrl, "accessibility", {
        tree: page.accessibilityTree,
      }, tool),
    );
  }
  if (page.har) {
    evidence.push(
      record(targetId, page.finalUrl, "har", {
        entries: page.har.entries,
        entryCount: page.har.entryCount,
      }, tool),
    );
  }
  if (page.screenshotBase64) {
    evidence.push(
      record(targetId, page.finalUrl, "screenshot", {
        base64: page.screenshotBase64,
        contentType: "image/jpeg",
      }, tool),
    );
  }
  return {
    evidence,
    summary: {
      url: page.finalUrl,
      status: page.status,
      title: page.title,
      domElementCount: Object.values(page.domCounts).reduce((a, b) => a + b, 0),
      stylesheetCount: page.stylesheets.length,
      imageCount: page.images.length,
      networkRequestCount: page.networkRequests.length,
      screenshotCaptured: page.screenshotBase64 !== null,
    },
  };
}

// Browser-backed capture. Playwright is the canonical runtime per AGENTS.md;
// chromium comes from the system package (apk chromium) via executablePath.
export async function capturePage(
  url: string,
  opts: { executablePath?: string; timeoutMs: number; maxRequests?: number },
): Promise<CapturedPage> {
  const { chromium } = await import("playwright-core");
  const executablePath =
    opts.executablePath ?? process.env.CHROMIUM_EXECUTABLE_PATH ?? "/usr/bin/chromium-browser";
  const browser = await chromium.launch({
    executablePath,
    args: ["--no-sandbox", "--disable-dev-shm-usage"],
  });
  const maxRequests = opts.maxRequests ?? 100;
  const harPath = `/tmp/c0py-capture-${randomUUID()}.har`;
  try {
    const context = await browser.newContext({
      viewport: DEFAULT_VIEWPORT,
      recordHar: { path: harPath, mode: "minimal" },
    });
    const page = await context.newPage();
    const networkRequests: CapturedPage["networkRequests"] = [];
    page.on("response", (res) => {
      if (networkRequests.length < maxRequests) {
        networkRequests.push({
          url: res.url(),
          method: res.request().method(),
          resourceType: res.request().resourceType(),
          status: res.status(),
        });
      }
    });
    const response = await page.goto(url, { timeout: opts.timeoutMs, waitUntil: "domcontentloaded" });
    await page.waitForTimeout(500);
    // NOTE: evaluate code must be a plain string — tsx/esbuild would inject
    // __name helpers into a transpiled function, which break in the browser.
    const captured = await page.evaluate(`(() => {
      const count = (sel) => document.querySelectorAll(sel).length;
      const pick = (el, props) => {
        if (!el) return Object.fromEntries(props.map((p) => [p, null]));
        const cs = getComputedStyle(el);
        return Object.fromEntries(props.map((p) => [p, cs.getPropertyValue(p) || null]));
      };
      const body = pick(document.body, ["font-family", "color", "background-color", "font-size"]);
      const h1 = pick(document.querySelector("h1"), ["font-family", "font-size", "font-weight", "color", "margin"]);
      return {
        title: document.title,
        description: document.querySelector('meta[name="description"]')?.getAttribute("content") ?? null,
        lang: document.documentElement.getAttribute("lang"),
        charset: document.characterSet,
        viewportMeta: document.querySelector('meta[name="viewport"]')?.getAttribute("content") ?? null,
        domCounts: {
          script: count("script"),
          link: count("link"),
          style: count("style"),
          img: count("img"),
          svg: count("svg"),
          form: count("form"),
          input: count("input"),
          button: count("button"),
          nav: count("nav"),
          header: count("header"),
          footer: count("footer"),
          main: count("main"),
          section: count("section"),
          h1: count("h1"),
          h2: count("h2"),
          h3: count("h3"),
          a: count("a"),
          table: count("table"),
          iframe: count("iframe"),
          video: count("video"),
          canvas: count("canvas"),
        },
        stylesheets: Array.from(document.querySelectorAll('link[rel="stylesheet"]')).map((l) => l.href),
        images: Array.from(document.querySelectorAll("img")).slice(0, 50).map((i) => i.src),
        computedStyle: { body, h1 },
      };
    })()`) as {
      title: string;
      description: string | null;
      lang: string | null;
      charset: string;
      viewportMeta: string | null;
      domCounts: Record<string, number>;
      stylesheets: string[];
      images: string[];
      computedStyle: Record<string, Record<string, string | null>>;
    };
    let screenshotBase64: string | null = null;
    try {
      screenshotBase64 = await page.screenshot({
        fullPage: true,
        type: "jpeg",
        quality: 60,
        timeout: Math.min(opts.timeoutMs, 10_000),
      }).then((b) => b.toString("base64"));
    } catch {
      // Screenshot failure is an evidence gap, not a capture failure.
      screenshotBase64 = null;
    }
    // Accessibility tree (measured; null on failure = explicit evidence gap).
    let accessibilityTree: CapturedPage["accessibilityTree"] = null;
    try {
      const acc = (page as unknown as { accessibility?: { snapshot(): Promise<unknown> } })
        .accessibility;
      accessibilityTree = (await acc?.snapshot()) as CapturedPage["accessibilityTree"] ?? null;
    } catch {
      accessibilityTree = null;
    }
    // HAR (measured; condensed to entry-level metadata).
    let har: CapturedPage["har"] = null;
    try {
      await context.close();
      const raw = await import("node:fs/promises").then((fs) => fs.readFile(harPath, "utf8"));
      const parsed = JSON.parse(raw) as {
        log: { entries: { request: { url: string; method: string }; response: { status: number; content: { mimeType?: string; size?: number } } }[] };
      };
      const entries = parsed.log.entries.slice(0, maxRequests).map((e) => ({
        url: e.request.url,
        method: e.request.method,
        status: e.response.status,
        mimeType: e.response.content?.mimeType ?? null,
        size: e.response.content?.size ?? null,
      }));
      har = { entries, entryCount: parsed.log.entries.length };
    } catch {
      har = null;
    }
    return {
      finalUrl: page.url(),
      status: response?.status() ?? 0,
      contentType: response?.headers()["content-type"] ?? null,
      ...captured,
      networkRequests,
      accessibilityTree,
      har,
      screenshotBase64,
    };
  } finally {
    await browser.close().catch(() => {});
    await import("node:fs/promises")
      .then((fs) => fs.unlink(harPath).catch(() => {}))
      .catch(() => {});
  }
}