/**
 * PrintabilityAnalyzer — FFF / SLA / SLS 3D-print pre-flight checker.
 *
 * Takes a triangle surface mesh (shared `SurfaceMesh` contract) plus optional
 * signed-distance field, and returns a `PrintabilityReport` with all fields
 * analytically computed — none are stubbed.
 *
 * ## Units
 *
 * The analyzer is **unit-agnostic**: it operates on raw coordinate values with
 * no built-in conversion.  By STL convention coordinates are typically in
 * millimetres, but the caller controls interpretation.  Use `scaleFactor` in
 * `PrintabilityOptions` if you need to normalise to a different unit before
 * analysis (vault rule G.GOLD.485: physical-unit assumptions are config, not
 * code).
 *
 * ## Algorithms
 *
 * ### Watertightness & Manifold check
 *
 * Build an undirected edge map: key = `min(a,b)_max(a,b)`.  Each directed
 * half-edge (a→b) for triangle winding contributes one count per undirected
 * key.  A closed, manifold mesh has every edge shared by exactly 2 triangles.
 *
 *   watertight  ⟺  ∀ edges: count == 2
 *   manifold    ⟺  ∀ edges: count ≤ 2  AND  no degenerate faces
 *
 * Degenerate face: any two vertex indices are equal, OR the cross-product
 * magnitude is < ε (zero-area face).
 *
 * ### Volume (divergence theorem)
 *
 * Signed volume via the divergence-theorem form of the surface integral:
 *
 *   V = (1/6) Σ_i  (v0 · (v1 × v2))
 *
 * where v0,v1,v2 are the three vertices of each triangle in winding order.
 * A positive result means outward-facing normals (right-hand rule pointing
 * away from the interior); negative means inward / inverted winding.
 *
 * ### Surface area
 *
 *   A = Σ_i  ½ ‖(v1−v0) × (v2−v0)‖
 *
 * ### Overhang detection
 *
 * Let N̂ be the outward face normal (unnormalised → normalised) and D̂ the
 * normalised build direction (default +Z).  A face overhangs when:
 *
 *   angle(N̂, −D̂)  <  (90° − threshold°)
 *
 * i.e. the face tilts toward the build plate more than `threshold` degrees
 * from the horizontal.  Equivalently:
 *
 *   dot(N̂, −D̂) > cos(90° − threshold°) = sin(threshold°)
 *
 * Faces whose centroid is within `bedEpsilon` of `aabb.min` along the build
 * direction are bed-contact faces and are excluded (they rest on the plate).
 *
 * ### Thin-wall heuristic (SDF sampling)
 *
 * Samples a uniform grid over the mesh AABB.  For each interior sample
 * (evaluateSDFNode(p) < 0) within the narrow band |d| < minWallThickness,
 * records 2·|d| as the local wall-thickness estimate.  Reports the minimum.
 *
 * This is a heuristic, not an exact medial-axis computation — it can miss
 * thin walls thinner than the grid spacing and may undercount on curved
 * surfaces.  Accurate wall-thickness analysis requires medial-axis extraction
 * or morphological erosion.
 *
 * ## Build direction convention
 *
 * `buildDirection` is a convention parameter, NOT a physics-derived value.
 * The default [0,0,1] means "print layers stack along +Z" — the most common
 * slicer convention for STL files.  Override this for machines that print
 * along a different axis, or when the part is oriented differently.
 *
 * @see SurfaceMesh    — shared mesh contract (AutoMesher.ts)
 * @see SDFNode        — signed-distance tree (SDFPointEvaluator.ts)
 * @see evaluateSDFNode — JS SDF evaluator
 */
import type { SurfaceMesh } from '../AutoMesher';
import type { SDFNode } from '../SDFPointEvaluator';
/** Three-component vector (no heap allocation in hot paths — use inline arrays). */
type Vec3 = readonly [number, number, number];
/** Axis-aligned bounding box. */
export interface AABB {
    min: Vec3;
    max: Vec3;
    size: Vec3;
}
/** Overhang summary returned in the report. */
export interface OverhangStats {
    /** Number of overhanging triangles. */
    count: number;
    /** Total area of overhanging triangles (same units² as geometry). */
    totalArea: number;
    /** Fraction of total surface area that overhangs: totalArea / surfaceArea. */
    fraction: number;
    /**
     * Worst overhang angle in degrees — the smallest angle between the
     * face normal and –buildDirection (0° = perfectly horizontal underside).
     * NaN when count === 0.
     */
    worstAngleDeg: number;
}
/**
 * Thin-wall sampling result.
 *
 * **Heuristic only** — this is a coarse grid-sampling estimate using the
 * signed-distance field.  It is NOT an exact medial-axis computation.  Thin
 * walls narrower than the grid spacing may not be detected, and curved
 * surfaces will yield conservative (under-)estimates.  For production-grade
 * wall-thickness analysis, use morphological erosion or medial-axis
 * extraction on the full SDF.
 */
export interface ThinWallHeuristic {
    /**
     * Minimum 2·|sdf| measured over interior narrow-band samples.
     * Undefined when no interior narrow-band samples were found.
     */
    minEstimatedThicknessMm: number | undefined;
    /** Number of interior narrow-band sample points queried. */
    sampleCount: number;
}
/** Full printability analysis report. */
export interface PrintabilityReport {
    /** True iff every edge is shared by exactly 2 triangles. */
    watertight: boolean;
    /** Number of edges shared by only 1 triangle (boundary edges). */
    openEdgeCount: number;
    /**
     * True iff watertight AND no edge is shared by >2 triangles AND no
     * degenerate (zero-area or repeated-index) face exists.
     */
    manifold: boolean;
    /**
     * Signed volume via the divergence theorem (same units³ as geometry).
     * Negative → winding is inverted (normals point inward).
     */
    volume: number;
    /** Total surface area (same units² as geometry). */
    surfaceArea: number;
    /**
     * True iff the computed volume is positive, meaning face normals are
     * consistently outward-facing.
     */
    orientationOutward: boolean;
    /** Axis-aligned bounding box of the mesh vertices. */
    aabb: AABB;
    /**
     * Whether the mesh AABB fits inside the given `buildVolume`.
     * Undefined when `buildVolume` was not provided.
     */
    fitsBuildVolume: boolean | undefined;
    /**
     * Overhang statistics.  Bed-contact faces (centroid within `bedEpsilon` of
     * aabb.min along buildDirection) are excluded.
     */
    overhangs: OverhangStats;
    /**
     * Thin-wall heuristic result.  Undefined when `sdf` and `minWallThickness`
     * were not both provided.
     */
    wallThickness: ThinWallHeuristic | undefined;
    /**
     * - `'not-printable'`  — mesh has topology errors or inverted winding.
     * - `'needs-supports'` — mesh is topologically sound but has overhangs.
     * - `'printable'`      — no detected issues.
     */
    recommendation: 'printable' | 'needs-supports' | 'not-printable';
}
/**
 * Options for `analyzePrintability`.
 *
 * All fields are optional; documented defaults match common FFF-printer
 * conventions but are NOT physics laws — override as needed.
 */
export interface PrintabilityOptions {
    /**
     * Build direction — the direction in which layers are stacked.
     *
     * **Convention, not physics**: [0,0,1] (+Z up) is the most common slicer
     * convention for STL files and is the default here.  Override for machines
     * that print along a different axis, or when the part is placed on its side.
     *
     * The vector does not need to be normalised — it is normalised internally.
     *
     * @default [0, 0, 1]
     */
    buildDirection?: Vec3;
    /**
     * Overhang threshold in degrees (0°–90°).
     *
     * Faces angled more than this many degrees from horizontal (away from the
     * build plate) are flagged as overhangs.  FFF printers typically bridge
     * ≤45° without supports; SLA/DLP can sometimes handle steeper angles.
     *
     * @default 45
     */
    overhangThresholdDeg?: number;
    /**
     * Optional build-volume AABB.  When provided, `fitsBuildVolume` is set in
     * the report.  Coordinates must be in the same unit system as the mesh.
     */
    buildVolume?: {
        min: Vec3;
        max: Vec3;
    };
    /**
     * Optional minimum wall thickness (same units as geometry).
     *
     * Only evaluated when `sdf` is also provided.  Triggers SDF grid sampling
     * to estimate the thinnest wall present; see `ThinWallHeuristic`.
     */
    minWallThickness?: number;
    /**
     * Optional SDF tree for interior wall-thickness sampling.
     *
     * Must describe the same solid as the surface mesh.  Interior is defined
     * as evaluateSDFNode(p) < 0.  Only used when `minWallThickness` is also
     * given.
     */
    sdf?: SDFNode;
    /**
     * Optional uniform scale factor applied to all vertex coordinates before
     * analysis.  Use to convert units (e.g. inches → mm: scaleFactor = 25.4).
     *
     * All report distances/areas/volumes are in the scaled units.
     *
     * @default 1
     */
    scaleFactor?: number;
    /**
     * Grid resolution for the thin-wall SDF sampling pass along each axis.
     *
     * Higher values give finer resolution at the cost of O(n³) SDF evaluations.
     *
     * @default [20, 20, 20]
     */
    sdfGridResolution?: readonly [number, number, number];
    /**
     * Bed-contact epsilon: faces whose centroid is within this distance of
     * `aabb.min` along the build direction are treated as resting on the print
     * bed and excluded from overhang detection.
     *
     * @default 1e-6
     */
    bedEpsilon?: number;
}
/**
 * Analyse a triangle surface mesh for 3D-print feasibility.
 *
 * @param mesh  Triangle surface mesh — `SurfaceMesh` from AutoMesher.ts.
 * @param opts  Analysis options (all optional; see `PrintabilityOptions`).
 * @returns     `PrintabilityReport` with all fields computed.
 */
export declare function analyzePrintability(mesh: SurfaceMesh, opts?: PrintabilityOptions): PrintabilityReport;
export {};
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