"""
Input Processing Layer

Parses and normalizes raw inputs (job description, company context, resume)
into structured intermediate representations for feature extraction.
"""

import json
import re
from dataclasses import dataclass, field, asdict
from typing import Optional


@dataclass
class CompanyContext:
    stage: str  # seed, series_a, series_b, growth, public, enterprise
    industry: str
    compensation_band: str  # e.g. "$150K-$200K" or "L5 band"
    location: str
    remote_type: str  # onsite, hybrid, remote, flexible
    headcount: Optional[int] = None
    glassdoor_rating: Optional[float] = None

    def validate(self) -> list[str]:
        errors = []
        valid_stages = {"seed", "series_a", "series_b", "series_c", "growth", "public", "enterprise", "government", "nonprofit"}
        if self.stage.lower() not in valid_stages:
            errors.append(f"Unknown company stage: {self.stage}")
        valid_remote = {"onsite", "hybrid", "remote", "flexible"}
        if self.remote_type.lower() not in valid_remote:
            errors.append(f"Unknown remote type: {self.remote_type}")
        return errors


@dataclass
class ProcessedInput:
    job_description: str
    company_context: CompanyContext
    resume_text: str
    jd_sections: dict = field(default_factory=dict)
    resume_sections: dict = field(default_factory=dict)
    data_quality_score: float = 0.0
    warnings: list = field(default_factory=list)

    def to_dict(self) -> dict:
        return {
            "job_description": self.job_description,
            "company_context": asdict(self.company_context),
            "resume_text": self.resume_text,
            "jd_sections": self.jd_sections,
            "resume_sections": self.resume_sections,
            "data_quality_score": self.data_quality_score,
            "warnings": self.warnings,
        }


class InputProcessor:
    """Processes raw inputs into structured representations."""

    def process(
        self,
        job_description: str,
        company_context: dict,
        resume_text: str,
    ) -> ProcessedInput:
        ctx = CompanyContext(**company_context)
        warnings = ctx.validate()

        jd_clean = self._clean_text(job_description)
        resume_clean = self._clean_text(resume_text)

        jd_sections = self._segment_jd(jd_clean)
        resume_sections = self._segment_resume(resume_clean)

        data_quality = self._assess_data_quality(jd_clean, resume_clean, ctx)

        if data_quality < 0.3:
            warnings.append("LOW_DATA_QUALITY: Inputs may be too sparse for reliable scoring")

        return ProcessedInput(
            job_description=jd_clean,
            company_context=ctx,
            resume_text=resume_clean,
            jd_sections=jd_sections,
            resume_sections=resume_sections,
            data_quality_score=data_quality,
            warnings=warnings,
        )

    def _clean_text(self, text: str) -> str:
        text = re.sub(r"\r\n", "\n", text)
        text = re.sub(r"[ \t]+", " ", text)
        text = re.sub(r"\n{3,}", "\n\n", text)
        return text.strip()

    def _segment_jd(self, jd: str) -> dict:
        """Heuristic segmentation of job description into sections."""
        sections = {
            "title": "",
            "responsibilities": "",
            "requirements": "",
            "preferred": "",
            "benefits": "",
            "about": "",
            "full_text": jd,
        }

        # Pattern-based extraction
        patterns = {
            "responsibilities": r"(?:responsibilities|what you.?ll do|the role|job duties)[:\s]*\n(.*?)(?=\n(?:requirements|qualifications|what we|preferred|benefits|about)|$)",
            "requirements": r"(?:requirements|qualifications|what we.?re looking for|must have|minimum)[:\s]*\n(.*?)(?=\n(?:preferred|nice to have|benefits|about|responsibilities)|$)",
            "preferred": r"(?:preferred|nice to have|bonus|ideal)[:\s]*\n(.*?)(?=\n(?:benefits|about|responsibilities|requirements)|$)",
            "benefits": r"(?:benefits|perks|what we offer|compensation)[:\s]*\n(.*?)(?=\n(?:about|responsibilities|requirements)|$)",
        }

        for section, pattern in patterns.items():
            match = re.search(pattern, jd, re.IGNORECASE | re.DOTALL)
            if match:
                sections[section] = match.group(1).strip()

        # Extract title from first non-empty line
        lines = [l.strip() for l in jd.split("\n") if l.strip()]
        if lines:
            sections["title"] = lines[0]

        return sections

    def _segment_resume(self, resume: str) -> dict:
        """Heuristic segmentation of resume."""
        sections = {
            "contact": "",
            "summary": "",
            "experience": "",
            "education": "",
            "skills": "",
            "projects": "",
            "certifications": "",
            "full_text": resume,
        }

        patterns = {
            "summary": r"(?:summary|profile|objective|about)[:\s]*\n(.*?)(?=\n(?:experience|education|skills|projects|work)|$)",
            "experience": r"(?:experience|work history|employment|professional background)[:\s]*\n(.*?)(?=\n(?:education|skills|projects|certifications)|$)",
            "education": r"(?:education|academic|degrees?)[:\s]*\n(.*?)(?=\n(?:skills|projects|certifications|experience)|$)",
            "skills": r"(?:skills|technical skills|technologies|competencies)[:\s]*\n(.*?)(?=\n(?:projects|certifications|education|experience)|$)",
        }

        for section, pattern in patterns.items():
            match = re.search(pattern, resume, re.IGNORECASE | re.DOTALL)
            if match:
                sections[section] = match.group(1).strip()

        return sections

    def _assess_data_quality(self, jd: str, resume: str, ctx: CompanyContext) -> float:
        """Score 0-1 representing input completeness and richness."""
        signals = 0
        total = 10

        # JD quality
        if len(jd) > 200:
            signals += 1
        if len(jd) > 500:
            signals += 1
        if any(kw in jd.lower() for kw in ["requirements", "qualifications", "responsibilities"]):
            signals += 1

        # Resume quality
        if len(resume) > 300:
            signals += 1
        if len(resume) > 800:
            signals += 1
        if re.search(r"\d{4}", resume):  # Contains years
            signals += 1
        if re.search(r"\d+%|\$\d+|\d+\s*(users|customers|team|engineers)", resume, re.IGNORECASE):
            signals += 1  # Quantified achievements

        # Company context quality
        if ctx.compensation_band and ctx.compensation_band != "unknown":
            signals += 1
        if ctx.industry and ctx.industry != "unknown":
            signals += 1
        if ctx.stage and ctx.stage != "unknown":
            signals += 1

        return signals / total