/**
 * Service for generating PDF resumes using RxResume v4 API.
 */

import { createWriteStream, existsSync } from "node:fs";
import { access, mkdir } from "node:fs/promises";
import { join } from "node:path";
import { Readable } from "node:stream";
import { pipeline } from "node:stream/promises";
import { createId } from "@paralleldrive/cuid2";
import { getDataDir } from "../config/dataDir";
import { getSetting } from "../repositories/settings";
import { getProfile } from "./profile";
import { pickProjectIdsForJob } from "./projectSelection";
import {
  extractProjectsFromProfile,
  resolveResumeProjectsSettings,
} from "./resumeProjects";
import { RxResumeClient } from "./rxresume-client";
import {
  resolveTracerPublicBaseUrl,
  rewriteResumeLinksWithTracer,
} from "./tracer-links";

const OUTPUT_DIR = join(getDataDir(), "pdfs");

export interface PdfResult {
  success: boolean;
  pdfPath?: string;
  error?: string;
}

export interface TailoredPdfContent {
  summary?: string | null;
  headline?: string | null;
  skills?: Array<{ name: string; keywords: string[] }> | null;
}

export interface GeneratePdfOptions {
  tracerLinksEnabled?: boolean;
  requestOrigin?: string | null;
  tracerCompanyName?: string | null;
}

/**
 * Get RxResume credentials from environment variables or database settings.
 */
async function getCredentials(): Promise<{
  email: string;
  password: string;
  baseUrl: string;
}> {
  // First check environment variables
  let email = process.env.RXRESUME_EMAIL || "";
  let password = process.env.RXRESUME_PASSWORD || "";
  const baseUrl = process.env.RXRESUME_URL || "https://v4.rxresu.me";

  // Fall back to database settings if env vars are not set
  if (!email) {
    email = (await getSetting("rxresumeEmail")) || "";
  }
  if (!password) {
    password = (await getSetting("rxresumePassword")) || "";
  }

  if (!email || !password) {
    throw new Error(
      "RxResume credentials not configured. Set RXRESUME_EMAIL and RXRESUME_PASSWORD environment variables or configure them in settings.",
    );
  }

  return { email, password, baseUrl };
}

/**
 * Download a file from a URL and save it to a local path.
 */
async function downloadFile(url: string, outputPath: string): Promise<void> {
  const response = await fetch(url);
  if (!response.ok) {
    throw new Error(
      `Failed to download PDF: HTTP ${response.status} ${response.statusText}`,
    );
  }

  if (!response.body) {
    throw new Error("No response body from PDF download");
  }

  // Convert Web ReadableStream to Node readable
  // biome-ignore lint/suspicious/noExplicitAny: response.body is a ReadableStream in the browser environment, but Node.js fetch implementation might have slight differences in types.
  const nodeReadable = Readable.fromWeb(response.body as any);
  const fileStream = createWriteStream(outputPath);

  await pipeline(nodeReadable, fileStream);
}

/**
 * Generate a tailored PDF resume for a job using the RxResume v4 API.
 *
 * Flow:
 * 1. Prepare resume data with tailored content and project selection
 * 2. Get auth token (uses cached token or logs in)
 * 3. Import/create resume on RxResume
 * 4. Request print to get PDF URL
 * 5. Download PDF locally
 * 6. Delete temporary resume from RxResume
 *
 * Token refresh is handled automatically on 401 errors.
 */
export async function generatePdf(
  jobId: string,
  tailoredContent: TailoredPdfContent,
  jobDescription: string,
  _baseResumePath?: string, // Deprecated: now always uses getProfile() which fetches from v4 API
  selectedProjectIds?: string | null,
  options?: GeneratePdfOptions,
): Promise<PdfResult> {
  console.log(`📄 Generating PDF for job ${jobId} using RxResume v4 API...`);

  try {
    // Ensure output directory exists
    if (!existsSync(OUTPUT_DIR)) {
      await mkdir(OUTPUT_DIR, { recursive: true });
    }

    // Get credentials and initialize client
    const { email, password, baseUrl } = await getCredentials();
    const client = new RxResumeClient(baseUrl);

    // Read base resume from profile (fetches from v4 API if configured, force fetch)
    const baseResume = JSON.parse(JSON.stringify(await getProfile(true)));

    // Sanitize skills: Ensure all skills have required schema fields (visible, description, id, level, keywords)
    // This fixes issues where the base JSON uses a shorthand format (missing required fields)
    if (
      baseResume.sections?.skills?.items &&
      Array.isArray(baseResume.sections.skills.items)
    ) {
      baseResume.sections.skills.items = baseResume.sections.skills.items.map(
        (skill: Record<string, unknown>) => ({
          ...skill,
          id: (skill.id as string) || createId(),
          visible: (skill.visible as boolean | undefined) ?? true,
          // Zod schema requires string, default to empty string if missing
          description: (skill.description as string | undefined) ?? "",
          level: (skill.level as number | undefined) ?? 1,
          keywords: (skill.keywords as string[] | undefined) || [],
        }),
      );
    }

    // Inject tailored summary
    if (tailoredContent.summary) {
      if (baseResume.sections?.summary) {
        baseResume.sections.summary.content = tailoredContent.summary;
      } else if (baseResume.basics?.summary) {
        baseResume.basics.summary = tailoredContent.summary;
      }
    }

    // Inject tailored headline
    if (tailoredContent.headline) {
      if (baseResume.basics) {
        baseResume.basics.headline = tailoredContent.headline;
        baseResume.basics.label = tailoredContent.headline;
      }
    }

    // Inject tailored skills
    if (tailoredContent.skills) {
      const newSkills = Array.isArray(tailoredContent.skills)
        ? tailoredContent.skills
        : typeof tailoredContent.skills === "string"
          ? JSON.parse(tailoredContent.skills)
          : null;

      if (newSkills && baseResume.sections?.skills) {
        // Ensure each skill item has required schema fields
        const existingSkills = (baseResume.sections.skills.items ||
          []) as Array<Record<string, unknown>>;
        const skillsWithSchema = newSkills.map(
          (newSkill: Record<string, unknown>) => {
            // Try to find matching existing skill to preserve id and other fields
            const existing = existingSkills.find(
              (s) => s.name === newSkill.name,
            );

            return {
              id:
                (newSkill.id as string) ||
                (existing?.id as string) ||
                createId(),
              visible:
                newSkill.visible !== undefined
                  ? (newSkill.visible as boolean)
                  : ((existing?.visible as boolean | undefined) ?? true),
              name:
                (newSkill.name as string) || (existing?.name as string) || "",
              description:
                newSkill.description !== undefined
                  ? (newSkill.description as string)
                  : (existing?.description as string) || "",
              level:
                newSkill.level !== undefined
                  ? (newSkill.level as number)
                  : ((existing?.level as number | undefined) ?? 0),
              keywords:
                (newSkill.keywords as string[]) ||
                (existing?.keywords as string[]) ||
                [],
            };
          },
        );

        baseResume.sections.skills.items = skillsWithSchema;
      }
    }

    // Select projects and set visibility
    try {
      let selectedSet: Set<string>;

      if (selectedProjectIds !== null && selectedProjectIds !== undefined) {
        selectedSet = new Set(
          selectedProjectIds
            .split(",")
            .map((s) => s.trim())
            .filter(Boolean),
        );
      } else {
        const { catalog, selectionItems } =
          extractProjectsFromProfile(baseResume);
        const overrideResumeProjectsRaw = await getSetting("resumeProjects");
        const { resumeProjects } = resolveResumeProjectsSettings({
          catalog,
          overrideRaw: overrideResumeProjectsRaw,
        });

        const locked = resumeProjects.lockedProjectIds;
        const desiredCount = Math.max(
          0,
          resumeProjects.maxProjects - locked.length,
        );
        const eligibleSet = new Set(resumeProjects.aiSelectableProjectIds);
        const eligibleProjects = selectionItems.filter((p) =>
          eligibleSet.has(p.id),
        );

        const picked = await pickProjectIdsForJob({
          jobDescription,
          eligibleProjects,
          desiredCount,
        });

        selectedSet = new Set([...locked, ...picked]);
      }

      const projectsSection = baseResume.sections?.projects;
      const projectItems = projectsSection?.items;
      if (Array.isArray(projectItems)) {
        for (const item of projectItems) {
          if (!item || typeof item !== "object") continue;
          const typedItem = item as Record<string, unknown>;
          const id = typeof typedItem.id === "string" ? typedItem.id : "";
          if (!id) continue;
          typedItem.visible = selectedSet.has(id);
        }
        projectsSection.visible = true;
      }
    } catch (err) {
      console.warn(
        `   ⚠️ Project visibility step failed for job ${jobId}:`,
        err,
      );
    }

    if (options?.tracerLinksEnabled) {
      const tracerBaseUrl = resolveTracerPublicBaseUrl({
        requestOrigin: options.requestOrigin,
      });
      if (!tracerBaseUrl) {
        throw new Error(
          "Tracer links are enabled but no public base URL is available. Set JOBOPS_PUBLIC_BASE_URL.",
        );
      }

      await rewriteResumeLinksWithTracer({
        jobId,
        resumeData: baseResume,
        publicBaseUrl: tracerBaseUrl,
        companyName: options.tracerCompanyName ?? null,
      });
    }

    // Use withAutoRefresh to handle token caching and 401 retry automatically
    const outputPath = join(OUTPUT_DIR, `resume_${jobId}.pdf`);

    await client.withAutoRefresh(email, password, async (token) => {
      let resumeId: string | null = null;

      try {
        // Create resume on RxResume
        console.log(`   📤 Uploading resume to RxResume...`);
        resumeId = await client.create(baseResume, token);
        console.log(`   ✅ Resume created with ID: ${resumeId}`);

        // Get PDF URL
        console.log(`   🖨️ Requesting PDF generation...`);
        const pdfUrl = await client.print(resumeId, token);
        console.log(`   ✅ PDF URL received: ${pdfUrl}`);

        // Download PDF
        console.log(`   📥 Downloading PDF...`);
        await downloadFile(pdfUrl, outputPath);
        console.log(`   ✅ PDF saved to: ${outputPath}`);

        // Cleanup: delete temporary resume from RxResume
        console.log(`   🧹 Cleaning up temporary resume...`);
        await client.delete(resumeId, token);
        console.log(`   ✅ Temporary resume deleted from RxResume`);
        resumeId = null;
      } finally {
        // Attempt cleanup if resume was created but not deleted
        if (resumeId) {
          try {
            console.log(`   🧹 Attempting cleanup of orphaned resume...`);
            await client.delete(resumeId, token);
          } catch {
            console.warn(`   ⚠️ Failed to cleanup orphaned resume ${resumeId}`);
          }
        }
      }
    });

    console.log(`✅ PDF generated successfully: ${outputPath}`);
    return { success: true, pdfPath: outputPath };
  } catch (error) {
    const message = error instanceof Error ? error.message : "Unknown error";
    console.error(`❌ PDF generation failed: ${message}`);
    return { success: false, error: message };
  }
}

/**
 * Check if a PDF exists for a job.
 */
export async function pdfExists(jobId: string): Promise<boolean> {
  const pdfPath = join(OUTPUT_DIR, `resume_${jobId}.pdf`);
  try {
    await access(pdfPath);
    return true;
  } catch {
    return false;
  }
}

/**
 * Get the path to a job's PDF.
 */
export function getPdfPath(jobId: string): string {
  return join(OUTPUT_DIR, `resume_${jobId}.pdf`);
}