"""
Canonical Resume data model — the SINGLE source of truth that drives both
the LLM tailoring contract (v4) and the canonical renderer.

Design principles:
- Flat list of bullets per role (no sub-sections, no §§HEADER§§ markers)
- 5-7 bullets per role max — the LLM selects the best per JD
- No Skills/Competencies section (per project policy R6)
- Keywords live in `summary` + per-bullet text only
- One canonical visual format applied to every tailored resume

Phase 4 — adopted after the user approved Option A on 2026-06-16.
"""

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


@dataclass
class Contact:
    """Candidate's contact line — rendered as one centered row under the name."""
    phone: str = ""
    email: str = ""
    linkedin: str = ""
    website: str = ""
    location: str = ""   # City, State, Country — needed for ATS "address" checks

    def render_line(self) -> str:
        """Format as a single dot-separated line for the resume header."""
        parts = []
        if self.phone:
            parts.append(self.phone)
        if self.email:
            parts.append(self.email)
        if self.linkedin:
            # Strip protocol for cleanness; the link layer adds it back
            ln = self.linkedin.replace("https://", "").replace("http://", "")
            parts.append(ln)
        if self.website:
            ws = self.website.replace("https://", "").replace("http://", "")
            parts.append(ws)
        if self.location:
            parts.append(self.location)
        return " · ".join(parts)


@dataclass
class Role:
    """One employment entry."""
    title: str
    company: str
    location: str = ""
    dates: str = ""          # e.g. "Jan 2023 – Present"
    bullets: list[str] = field(default_factory=list)


@dataclass
class Education:
    """One education entry."""
    degree: str              # e.g. "Diploma — Product & Brand Management"
    institution: str         # e.g. "IIM Rohtak"
    dates: str = ""          # e.g. "Mar 2023 – Sep 2023"


@dataclass
class Resume:
    """The complete canonical resume."""
    name: str
    contact: Contact = field(default_factory=Contact)
    summary: str = ""        # 4-6 sentences, opens with recruiter pitch
    skills: list[str] = field(default_factory=list)  # flat skill list; renderer groups into a categorized SKILLS section
    roles: list[Role] = field(default_factory=list)
    achievements: list[str] = field(default_factory=list)
    education: list[Education] = field(default_factory=list)

    # ──────────────────────────────────────────────────────────────────
    # Serialization (LLM round-trip)
    # ──────────────────────────────────────────────────────────────────
    def to_dict(self) -> dict:
        return {
            "name": self.name,
            "contact": asdict(self.contact),
            "summary": self.summary,
            "skills": list(self.skills),
            "roles": [asdict(r) for r in self.roles],
            "achievements": list(self.achievements),
            "education": [asdict(e) for e in self.education],
        }

    def to_json(self, indent: int = 2) -> str:
        return json.dumps(self.to_dict(), ensure_ascii=False, indent=indent)

    @classmethod
    def from_dict(cls, data: dict) -> "Resume":
        c = data.get("contact") or {}
        return cls(
            name=data.get("name", "Your Name"),
            contact=Contact(
                phone=c.get("phone", ""),
                email=c.get("email", ""),
                linkedin=c.get("linkedin", ""),
                website=c.get("website", ""),
                location=c.get("location", ""),
            ),
            summary=data.get("summary", ""),
            skills=[str(s) for s in (data.get("skills") or []) if str(s).strip()],
            roles=[
                Role(
                    title=r.get("title", ""),
                    company=r.get("company", ""),
                    location=r.get("location", ""),
                    dates=r.get("dates", ""),
                    bullets=[str(b) for b in (r.get("bullets") or []) if str(b).strip()],
                )
                for r in (data.get("roles") or [])
            ],
            achievements=[str(a) for a in (data.get("achievements") or []) if str(a).strip()],
            education=[
                Education(
                    degree=e.get("degree", ""),
                    institution=e.get("institution", ""),
                    dates=e.get("dates", ""),
                )
                for e in (data.get("education") or [])
            ],
        )

    # ──────────────────────────────────────────────────────────────────
    # Flat-text view (used by the ATS scorer)
    # ──────────────────────────────────────────────────────────────────
    def to_flat_text(self) -> str:
        """Plain-text rendering for keyword matching / ATS scoring."""
        parts = [self.name]
        cl = self.contact.render_line()
        if cl:
            parts.append(cl)
        if self.summary:
            parts.append("PROFESSIONAL SUMMARY")
            parts.append(self.summary)
        if self.skills:
            parts.append("SKILLS")
            # Emit in chunks of 8 (mirrors the renderer's categorized lines) so
            # no single line trips the scorer's anti-spam strip (15+ separators).
            for i in range(0, len(self.skills), 8):
                parts.append(", ".join(self.skills[i:i + 8]))
        if self.roles:
            parts.append("PROFESSIONAL EXPERIENCE")
            for r in self.roles:
                parts.append(f"{r.title}")
                meta = " · ".join(filter(None, [r.company, r.location]))
                if meta:
                    parts.append(meta)
                if r.dates:
                    parts.append(r.dates)
                for b in r.bullets:
                    parts.append(f"• {b}")
        if self.achievements:
            parts.append("KEY ACHIEVEMENTS")
            for a in self.achievements:
                parts.append(f"• {a}")
        if self.education:
            parts.append("EDUCATION")
            for e in self.education:
                parts.append(e.degree)
                meta = " · ".join(filter(None, [e.institution, e.dates]))
                if meta:
                    parts.append(meta)
        return "\n".join(parts)


# ─────────────────────────────────────────────────────────────────────────
# Validation helpers
# ─────────────────────────────────────────────────────────────────────────

def validate_resume(resume: Resume, strict: bool = False) -> list[str]:
    """
    Return a list of validation warnings. Empty list = resume is well-formed.

    If `strict=True`, also enforces canonical format limits (5-7 bullets/role,
    name/contact/summary present, etc.). Used in the renderer to flag issues
    before writing.
    """
    issues: list[str] = []

    if not resume.name or resume.name == "Your Name":
        issues.append("name is missing or placeholder")

    if not resume.contact.email and not resume.contact.phone:
        issues.append("contact has no email or phone")

    if not resume.summary or len(resume.summary) < 100:
        issues.append(f"summary is too short ({len(resume.summary)} chars; min 100)")

    if not resume.roles:
        issues.append("no roles in experience section")

    if strict:
        for i, role in enumerate(resume.roles):
            n = len(role.bullets)
            if n < 2:
                issues.append(f"role {i} ({role.title}) has only {n} bullets — recommend 3+")
            elif n > 8:
                issues.append(f"role {i} ({role.title}) has {n} bullets — recommend 5-7")

    if not resume.education:
        issues.append("no education entries (recommended)")

    return issues


# ─────────────────────────────────────────────────────────────────────────
# JSON Schema (for LLM prompt embedding)
# ─────────────────────────────────────────────────────────────────────────

RESUME_JSON_SCHEMA_DESCRIPTION = """\
{
  "name": "<full name>",
  "contact": {
    "phone": "<phone>",
    "email": "<email>",
    "linkedin": "<linkedin URL>",
    "website": "<optional personal site>",
    "location": "<city, state, country — keep the candidate's existing value verbatim>"
  },
  "summary": "<4-6 sentence summary. Opens with: 'Strong-fit candidate for [role] at [company]: ...' Weave 8+ JD keywords naturally.>",
  "roles": [
    {
      "title": "<job title>",
      "company": "<company name>",
      "location": "<city, country>",
      "dates": "<e.g. Jan 2023 – Present>",
      "bullets": [
        "<Action-verb-start bullet with quantified impact and JD keywords>",
        "<5-7 bullets per role; pick the best across all original sub-projects>"
      ]
    }
  ],
  "achievements": [
    "<3-5 top quantified highlights cutting across roles>"
  ],
  "education": [
    {"degree": "<Degree — Specialization>", "institution": "<School>", "dates": "<date range>"}
  ]
}
"""