import express from "express";
import multer from "multer";
import cors from "cors";
import * as fs from "fs";
import * as path from "path";
import { Request, Response, NextFunction } from "express";
import pdfParse from "pdf-parse";
import OpenAI from "openai";
import dotenv from "dotenv";
import { getRecommendations } from "../utils/parseResume";
dotenv.config();

// Initialize OpenAI client

const openai = new OpenAI({
  apiKey: process.env.OPENAI_API_KEY, // Make sure to set this in your environment
});

interface ParsedData {
  skills: string[];
  experience: string[];
  education: string[];
}

// Add type declaration for Multer request
interface MulterRequest extends Request {
  file: Express.Multer.File;
}

interface QuestionnaireData {
  currentStatus: "student" | "unemployed";
  interimRole: boolean;
  dreamRole: string;
  motivation: string;
  learningPreference: "videos" | "projects" | "reading" | "all";
  timeCommitment: "1-2" | "2-4" | "4+";
  flexibleForInterim: boolean;
  challenges: string[];
  timeframe: "6months" | "12months" | "2years" | "flexible";
}

const app = express();

// Configure CORS
app.use(
  cors({
    origin: "*", // Your frontend URL
    methods: ["POST", "GET", "OPTIONS"],
    allowedHeaders: ["Content-Type"],
  })
);


// Create uploads directory if it doesn't exist
if (!fs.existsSync("/tmp/uploads")) {
  fs.mkdirSync("/tmp/uploads");
}

// Configure multer for file uploads
const upload = multer({
  dest: "/tmp/uploads/",
  fileFilter: (req, file, cb) => {
    if (file.mimetype === "application/pdf") {
      cb(null, true);
    } else {
      cb(null, false);
      return cb(new Error("Only PDF files are allowed"));
    }
  },
});

// Import pdf-parse with options
const pdfParseOptions = {
  // Ensure all pages are read
  max: 0,
  // Use a more robust page rendering
  pagerender: function (pageData: any) {
    const renderOptions = {
      normalizeWhitespace: false,
      disableCombineTextItems: false,
    };
    return pageData
      .getTextContent(renderOptions)
      .then(function (textContent: any) {
        let lastY,
          text = "";
        for (let item of textContent.items) {
          if (lastY == item.transform[5] || !lastY) {
            text += item.str;
          } else {
            text += "\n" + item.str;
          }
          lastY = item.transform[5];
        }
        return text;
      });
  },
};

const parseResumeContent = (text: string) => {
  console.log("Raw text from PDF:", text); // Debug log to see the raw text

  // More flexible regex patterns
  const skillsMatch = text.match(
    /(?:SKILLS?|TECHNICAL SKILLS?)[:\s]+([\s\S]*?)(?=(?:EXPERIENCE|EDUCATION|WORK|EMPLOYMENT|PROFESSIONAL|$))/i
  );
  const experienceMatch = text.match(
    /(?:EXPERIENCE|WORK|EMPLOYMENT|PROFESSIONAL)[:\s]+([\s\S]*?)(?=(?:EDUCATION|SKILLS?|$))/i
  );
  const educationMatch = text.match(
    /(?:EDUCATION|ACADEMIC|QUALIFICATIONS)[:\s]+([\s\S]*?)(?=(?:EXPERIENCE|WORK|SKILLS?|$))/i
  );

  // Process skills
  const skillsText = skillsMatch ? skillsMatch[1] : "";
  const skillsList = skillsText
    .split(/[,\n•]/) // Split by commas, newlines, or bullet points
    .map((skill) => skill.trim())
    .filter((skill) => skill.length > 2); // Filter out very short strings

  // Process experience
  const experienceText = experienceMatch ? experienceMatch[1] : "";
  const experienceList = experienceText
    .split(/(?:\r?\n){2,}/) // Split by multiple newlines
    .map((exp) => exp.replace(/^\s*[•-]\s*/gm, "").trim()) // Remove bullet points
    .filter((exp) => exp.length > 10); // Filter out short lines

  // Process education
  const educationText = educationMatch ? educationMatch[1] : "";
  const educationList = educationText
    .split(/(?:\r?\n){2,}/)
    .map((edu) => edu.replace(/^\s*[•-]\s*/gm, "").trim())
    .filter((edu) => edu.length > 10);

  // Debug logs
  console.log("Found sections:", {
    skills: !!skillsMatch,
    experience: !!experienceMatch,
    education: !!educationMatch,
  });

  console.log("Parsed sections:", {
    skillsCount: skillsList.length,
    experienceCount: experienceList.length,
    educationCount: educationList.length,
    skillsList,
    experienceList,
    educationList,
  });

  return {
    skills: skillsList,
    experience: experienceList,
    education: educationList,
  };
};

const handleFileUpload = async (req: Request, res: Response): Promise<void> => {
  let filePath = "";
  try {
    if (!req.file) {
      res.status(400).json({ error: "No file uploaded" });
      return;
    }

    const questionnaireData = JSON.parse(req.body.questionnaireData || "{}");
    console.log("Received dream role:", questionnaireData.dreamRole);

    filePath = req.file.path;
    console.log("File received:", req.file);

    const dataBuffer = fs.readFileSync(filePath);
    const pdfData = await pdfParse(dataBuffer);

    // Parse resume sections
    const parsedData = parseResumeContent(pdfData.text);
    console.log("Parsed resume data:", parsedData);

    // Get recommendations using the parsed data
    const recommendations = await getRecommendations(
      parsedData,
      questionnaireData.dreamRole,
      questionnaireData
    );

    // Update the OpenAI prompt to specifically request benefits information
    const completion = await openai.chat.completions.create({
      model: "gpt-4o-mini", // or whichever model you're using
      messages: [
        {
          role: "system",
          content:
            "You are a career advisor creating personalized course recommendations.",
        },
        {
          role: "user",
          content: `Create detailed course recommendations based on:
            Skills: ${parsedData.skills.join(", ")}
            Experience: ${parsedData.experience.join("\n")}
            Education: ${parsedData.education.join("\n")}
            Dream Role: ${questionnaireData.dreamRole}

            Additional Personal Context:
            - Current Status: ${questionnaireData.currentStatus}
            - Interested in Interim Role: ${questionnaireData.interimRole}
            - Motivation: ${questionnaireData.motivation}
            - Preferred Learning Style: ${questionnaireData.learningPreference}
            - Daily Time Commitment: ${questionnaireData.timeCommitment} hours
            - Main Challenges: ${questionnaireData.challenges.join(", ")}
            - Target Timeframe: ${questionnaireData.timeframe}
            
            For each course, you MUST include:
            - title: A specific course title
            - description: Brief description of the course content
            - platform: Where the course is offered (Coursera, Udemy, etc.)
            - duration: How long it takes to complete
            - level: Difficulty level
            - link: URL to the course
            - benefitsInterim: IMPORTANT - Specific benefits for an interim role
            - benefitsDream: IMPORTANT - Specific benefits for the dream role

            Return exactly this JSON structure:
            {
              "courses": [
                {
                  "title": "Course Name",
                  "description": "Course Description",
                  "duration": "Duration",
                  "platform": "Platform Name",
                  "level": "Difficulty Level",
                  "link": "https://example.com",
                  "benefitsInterim": "Detailed explanation of how this helps with interim roles",
                  "benefitsDream": "Detailed explanation of how this helps with the dream role"
                }
              ],
              "roles": [
                {
                  "title": "Role Title",
                  "description": "Role Description",
                  "timeline": "Timeline",
                  "salary": "Salary Range"
                }
              ]
            }`,
        },
      ],
      response_format: { type: "json_object" },
    });

    // Make sure we're properly handling the response
    const result = JSON.parse(completion.choices[0].message.content || "{}");

    // Validate that each course has the required fields
    const validatedCourses = result.courses.map((course: any) => {
      return {
        title: course.title || "Course Title",
        description: course.description || "No description available",
        duration: course.duration || "Unknown duration",
        platform: course.platform || "Online platform",
        level: course.level || "Intermediate",
        link: course.link || "#",
        benefitsInterim:
          course.benefitsInterim ||
          "Builds foundational skills needed for entry-level positions",
        benefitsDream:
          course.benefitsDream ||
          "Contributes to the skill set required for your dream role",
      };
    });

    // Return the validated courses
    res.json({
      skills: parsedData.skills,
      experience: parsedData.experience,
      education: parsedData.education,
      recommendations: {
        courses: recommendations.courses || [],
        roles: recommendations.roles || [],
      },
    });
  } catch (error) {
    console.error("Server Error:", error);
    res.status(500).json({
      error: "Failed to process resume",
      details: error instanceof Error ? error.message : "Unknown error",
    });
  } finally {
    // Clean up uploaded file
    if (filePath && fs.existsSync(filePath)) {
      fs.unlinkSync(filePath);
    }
  }
};

app.post("/api/parse-resume", upload.single("resume"), handleFileUpload);
app.get("/api/test", (req, res) => {
  res.json({ message: "Hello, World!" });
});
const PORT = process.env.PORT || 3001;

app
  .listen(PORT, () => {
    console.log(`Server running on port ${PORT}`);
  })
  .on("error", (err: NodeJS.ErrnoException) => {
    if (err.code === "EADDRINUSE") {
      console.log(`Port ${PORT} is busy, trying ${PORT}...`);
      app.listen(PORT);
    } else {
      console.error("Server error:", err);
      process.exit(1);
    }
  });