"""8-step pre-completion validator for engineering drawings."""

from __future__ import annotations

import re
from dataclasses import dataclass, field
from pathlib import Path
from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from backends.base import AutoCADBackend


REAL_DIMENSION_TYPES = {
    "DIMENSION",
    "DIMLINEAR",
    "DIMALIGNED",
    "DIMANGULAR",
    "DIMRADIUS",
    "DIMDIAMETER",
    "DIMORDINATE",
}

# Patterns that suggest a TEXT/MTEXT entity is masquerading as a dimension.
DIMENSION_LIKE_TEXT = re.compile(
    r"(Ø|⌀|∅|%%c|%%C|R\d|±|%%p|\d+\s*[×x]\s*\d+|\d+\.\d+\s*mm)",
    re.IGNORECASE,
)

# R27 — match SPUR / HELICAL as whole words (not substrings of e.g.
# "SPURIOUS") when checking title/helix consistency.
_SPUR_RE = re.compile(r"\bSPUR\b", re.IGNORECASE)
_HELICAL_RE = re.compile(r"\bHELICAL\b", re.IGNORECASE)

# Layers that hold title-block text (scoped scan target for step 5).
_TITLE_LAYERS = {"TITLE", "TITLEBLOCK"}


@dataclass
class ValidationFinding:
    """One issue surfaced by the validator."""

    severity: str  # "error" | "warning" | "info"
    code: str
    message: str
    detail: dict = field(default_factory=dict)


@dataclass
class ValidationResult:
    """Aggregate of validator findings."""

    ok: bool
    findings: list[ValidationFinding]
    summary: dict

    def to_dict(self) -> dict:
        return {
            "ok": self.ok,
            "summary": self.summary,
            "findings": [
                {
                    "severity": f.severity,
                    "code": f.code,
                    "message": f.message,
                    "detail": f.detail,
                }
                for f in self.findings
            ],
        }


class DrawingValidator:
    """8-step pre-completion validator."""

    async def run(
        self,
        backend: AutoCADBackend,
        *,
        expected: dict | None = None,
    ) -> ValidationResult:
        """Run all 8 checks; return aggregate ValidationResult."""

        findings: list[ValidationFinding] = []
        expected = expected or {}
        ents: list = []

        # 1 — fake dimensions
        try:
            ents = await backend.entity_list(limit=10000)
            text_likes = [
                e
                for e in ents
                if e.type in ("TEXT", "MTEXT")
                and DIMENSION_LIKE_TEXT.search(getattr(e, "properties", {}).get("text", "") or "")
            ]
            real_dims = [e for e in ents if e.type in REAL_DIMENSION_TYPES]
            if text_likes:
                findings.append(
                    ValidationFinding(
                        "warning",
                        "fake_dimension_text",
                        f"{len(text_likes)} TEXT/MTEXT entities look like dimensions "
                        "(Ø, ±, R, etc.) — use dimension_* tools instead",
                        {
                            "sample_handles": [t.handle for t in text_likes[:5]],
                            "real_dim_count": len(real_dims),
                        },
                    )
                )
        except Exception as exc:
            findings.append(
                ValidationFinding(
                    "warning",
                    "dim_check_failed",
                    str(exc),
                )
            )

        # 2 — hidden orphans
        try:
            hidden = [e for e in ents if not e.visible]
            if hidden:
                findings.append(
                    ValidationFinding(
                        "error",
                        "hidden_orphans",
                        f"{len(hidden)} entities have visible=False — hide-fallback "
                        "is forbidden, use entity_delete",
                        {"sample_handles": [h.handle for h in hidden[:5]]},
                    )
                )
        except Exception:
            pass

        # 3 — linetypes
        try:
            lts = {x.lower() for x in await backend.linetype_list()}
            missing = [lt for lt in ("center", "hidden", "phantom") if lt not in lts]
            if missing:
                findings.append(
                    ValidationFinding(
                        "error",
                        "linetypes_missing",
                        f"Standard linetypes not loaded: {', '.join(missing).upper()}",
                        {"missing": missing},
                    )
                )
        except Exception as exc:
            findings.append(
                ValidationFinding(
                    "warning",
                    "linetype_check_failed",
                    str(exc),
                )
            )

        # 4 — gear views (heuristic, only if expected demands)
        if expected.get("must_have_bore") or expected.get("must_have_keyway"):
            bore_circles = [e for e in ents if e.type == "CIRCLE" and e.layer == "GEOMETRY"]
            if expected.get("must_have_bore") and len(bore_circles) < 1:
                findings.append(
                    ValidationFinding(
                        "error",
                        "bore_missing",
                        "Expected bore but no circle on GEOMETRY layer found",
                    )
                )
            # draw_keyed_bore emits the keyway notch as an OPEN 4-point polyline
            # on GEOMETRY — requiring `closed` here made this a permanent
            # false-negative. Match a small (3-6 point) polyline, open or closed.
            keyway_polys = [
                e
                for e in ents
                if e.type in ("LWPOLYLINE", "POLYLINE")
                and e.layer == "GEOMETRY"
                and 3 <= len(e.properties.get("points", [])) <= 6
            ]
            if expected.get("must_have_keyway") and len(keyway_polys) < 1:
                findings.append(
                    ValidationFinding(
                        "warning",
                        "keyway_section_unverified",
                        "Could not confirm keyway via heuristic "
                        "(small 3-6 point polyline on GEOMETRY)",
                    )
                )

        # 5 — title consistency
        helix = expected.get("helix_angle")
        if helix:
            # R27 — scope the scan to title-block text where possible (TITLE /
            # TITLEBLOCK layer); fall back to all TEXT-layer text if no title
            # layer carries any text.
            title_block_texts = [
                e.properties.get("text", "") or ""
                for e in ents
                if e.type in ("TEXT", "MTEXT") and e.layer in _TITLE_LAYERS
            ]
            if title_block_texts:
                title_texts = title_block_texts
            else:
                title_texts = [
                    e.properties.get("text", "") or ""
                    for e in ents
                    if e.type in ("TEXT", "MTEXT") and e.layer == "TEXT"
                ]
            joined = " | ".join(title_texts)
            # R27 — whole-word matching so "SPURIOUS" no longer trips SPUR.
            has_spur = bool(_SPUR_RE.search(joined))
            has_helical = bool(_HELICAL_RE.search(joined))
            if has_spur and has_helical:
                findings.append(
                    ValidationFinding(
                        "error",
                        "title_helical_spur",
                        "Title contains 'HELICAL SPUR GEAR' — invalid; use "
                        "'HELICAL GEAR' or 'SPUR GEAR'",
                    )
                )
            elif has_spur:
                findings.append(
                    ValidationFinding(
                        "error",
                        "title_says_spur_for_helical",
                        f"Title contains SPUR but part is helical (helix_angle={helix})",
                        {"sample": joined[:200]},
                    )
                )

        # 6 — saved to disk
        try:
            info = await backend.drawing_info()
            saved_attr = getattr(info, "saved", None)
            full_path = getattr(info, "full_path", "") or ""
            if not saved_attr:
                findings.append(
                    ValidationFinding(
                        "error",
                        "not_saved",
                        "Drawing has unsaved changes — call drawing_save before finalize",
                        {"full_path": full_path},
                    )
                )
            elif full_path and not Path(full_path).exists():
                findings.append(
                    ValidationFinding(
                        "error",
                        "file_missing",
                        f"Drawing reports saved=True but file not on disk: {full_path}",
                    )
                )
        except Exception as exc:
            findings.append(
                ValidationFinding(
                    "warning",
                    "save_check_failed",
                    str(exc),
                )
            )

        # 7 — screenshot
        try:
            shot = await backend.view_screenshot()
            if not shot:
                findings.append(
                    ValidationFinding(
                        "info",
                        "screenshot_unavailable",
                        "Screenshot returned no bytes (ezdxf needs matplotlib install)",
                    )
                )
        except Exception as exc:
            findings.append(
                ValidationFinding(
                    "info",
                    "screenshot_failed",
                    str(exc),
                )
            )

        # 8 — dwg path returned
        try:
            info = await backend.drawing_info()
            if not getattr(info, "full_path", ""):
                findings.append(
                    ValidationFinding(
                        "warning",
                        "no_path",
                        "drawing_info.full_path is empty",
                    )
                )
        except Exception:
            pass

        summary = {
            sev: sum(1 for f in findings if f.severity == sev)
            for sev in ("error", "warning", "info")
        }
        return ValidationResult(
            ok=summary["error"] == 0,
            findings=findings,
            summary=summary,
        )