# constraint_checks.py - V1.0 (Geometric Constraint Validator)
# Deterministic algebraic checks using SymPy.
# Each function verifies a specific geometric relationship and logs
# the result to the GeometryAnchor (verified_facts or warnings).

import logging
from sympy import simplify, symbols, Eq, solve, Rational

from geometry_types import Point, Line, Segment, Circle, GeometryAnchor

logger = logging.getLogger(__name__)


def check_point_on_circle(p: Point, circle: Circle, anchor: GeometryAnchor):
    """
    Verifies algebraically whether point p lies on the circle boundary.
    Injects a verified_fact or a warning into the anchor.
    """
    try:
        if circle.contains(p):
            anchor.add_fact(
                f"✓ הנקודה {p} נמצאת על המעגל (מרכז {circle.center}, r={circle.radius})"
            )
        else:
            lhs = (p.x - circle.center.x)**2 + (p.y - circle.center.y)**2
            anchor.add_warning(
                f"✗ הנקודה {p} אינה על המעגל — "
                f"חישוב: {simplify(lhs)} ≠ r²={simplify(circle.radius**2)}. "
                f"ייתכן שה-OCR חילץ קואורדינטות שגויות."
            )
    except Exception as e:
        logger.error(f"[CONSTRAINT] check_point_on_circle failed: {e}")
        anchor.add_warning(f"⚠️ לא ניתן לאמת שהנקודה {p.name} על המעגל: {e}")


def check_point_on_line(p: Point, line: Line, anchor: GeometryAnchor):
    """
    Verifies algebraically whether point p lies on the line ax + by + c = 0.
    """
    try:
        if line.contains(p):
            anchor.add_fact(
                f"✓ הנקודה {p} נמצאת על הישר {line}"
            )
        else:
            val = simplify(line.a * p.x + line.b * p.y + line.c)
            anchor.add_warning(
                f"✗ הנקודה {p} אינה על הישר {line} — "
                f"הצבה נותנת {val} ≠ 0"
            )
    except Exception as e:
        logger.error(f"[CONSTRAINT] check_point_on_line failed: {e}")
        anchor.add_warning(f"⚠️ לא ניתן לאמת שהנקודה {p.name} על הישר: {e}")


def check_is_diameter(segment: Segment, circle: Circle, anchor: GeometryAnchor):
    """
    Checks if a segment is a diameter by verifying its midpoint equals the circle center.
    This is the most critical check for preventing midpoint hallucination.
    """
    try:
        mid = segment.midpoint()
        center = circle.center
        if mid == center:
            anchor.add_fact(
                f"✓ הקטע {segment.p1.name}{segment.p2.name} הוא קוטר — "
                f"אמצעו {mid} = מרכז המעגל {center}"
            )
        else:
            anchor.add_warning(
                f"✗ הקטע {segment.p1.name}{segment.p2.name} אינו קוטר — "
                f"אמצע הקטע הוא {mid}, אך מרכז המעגל הוא {center}. "
                f"⚠️ אל תניח שמרכז המעגל הוא נקודת האמצע של קטע זה!"
            )
    except Exception as e:
        logger.error(f"[CONSTRAINT] check_is_diameter failed: {e}")
        anchor.add_warning(f"⚠️ לא ניתן לאמת האם הקטע {segment} הוא קוטר: {e}")


def check_perpendicular_lines(slope1, slope2, anchor: GeometryAnchor, label1="ישר 1", label2="ישר 2"):
    """
    Verifies that two lines (given by slopes) are perpendicular: m1 * m2 = -1.
    """
    try:
        product = simplify(slope1 * slope2)
        if product == -1:
            anchor.add_fact(
                f"✓ {label1} ו-{label2} מאונכים — מכפלת שיפועים = {product} = -1"
            )
        else:
            anchor.add_warning(
                f"✗ {label1} ו-{label2} אינם מאונכים — מכפלת שיפועים = {product} ≠ -1"
            )
    except Exception as e:
        logger.error(f"[CONSTRAINT] check_perpendicular_lines failed: {e}")
        anchor.add_warning(f"⚠️ לא ניתן לאמת אנכיות: {e}")


def find_circle_center_from_diameters(
    d1: Segment,
    d2: Segment,
    anchor: GeometryAnchor
) -> Point:
    """
    Finds the circle center deterministically as the intersection of two diameter segments.
    This eliminates any need for the LLM to 'guess' the center.
    """
    try:
        x, y = symbols('x y')

        def line_eq_through(p1: Point, p2: Point):
            if simplify(p2.x - p1.x) == 0:
                # Vertical line
                return Eq(x, p1.x)
            slope = Rational(p2.y - p1.y, p2.x - p1.x)
            return Eq(y, slope * (x - p1.x) + p1.y)

        eq1 = line_eq_through(d1.p1, d1.p2)
        eq2 = line_eq_through(d2.p1, d2.p2)

        solution = solve([eq1, eq2], [x, y])

        if not solution:
            anchor.add_warning(
                "[SOLVER] לא ניתן לחשב מרכז מעגל מחיתוך שני קטרים — הישרים מקבילים?"
            )
            return None

        cx = solution[x] if isinstance(solution, dict) else solution[0]
        cy = solution[y] if isinstance(solution, dict) else solution[1]
        center = Point(name="M", x=simplify(cx), y=simplify(cy))
        anchor.add_fact(
            f"✓ מרכז המעגל M חושב כחיתוך קטרים: M = {center}"
        )
        return center

    except Exception as e:
        logger.error(f"[CONSTRAINT] find_circle_center_from_diameters failed: {e}")
        anchor.add_warning(f"⚠️ חישוב מרכז ממעגל נכשל: {e}")
        return None


def check_distance(p1: Point, p2: Point, expected_distance, anchor: GeometryAnchor, label=""):
    """
    Verifies the distance between two points matches an expected value.
    """
    try:
        actual = simplify(p1.distance_to(p2))
        expected = simplify(expected_distance)
        desc = label or f"{p1.name}↔{p2.name}"
        if simplify(actual - expected) == 0:
            anchor.add_fact(f"✓ המרחק {desc} = {actual} (תואם לנתון)")
        else:
            anchor.add_warning(
                f"✗ המרחק {desc}: חישוב={actual} ≠ נתון={expected}"
            )
    except Exception as e:
        logger.error(f"[CONSTRAINT] check_distance failed: {e}")
        anchor.add_warning(f"⚠️ בדיקת מרחק נכשלה: {e}")