"""All tunable constants. v1 has no GUI dialog: edit here, re-run.

A future version may read overrides from <project>/fill_res_config.json.
"""

# --- Grid sizing ---
# Benchmarked on the VOUT+ plane (147x59 mm): R changes < 0.3% from
# 150 um cells down to 50 um. Accuracy is feature-limited (slots/necks
# narrower than one cell), not plane-limited - override CELL_UM_OVERRIDE
# for boards with sub-cell slots.
TARGET_CELLS = 2_000_000        # auto cell size aims for roughly this many cells
HARD_MAX_CELLS = 16_000_000     # abort above this (see GridSizeError message)
MIN_CELL_UM = 25.0              # clamp for auto cell size
MAX_CELL_UM = 500.0
CELL_UM_OVERRIDE: float | None = None   # force a cell size, bypasses auto (not HARD_MAX)
MARGIN_CELLS = 2                # empty guard cells around the copper bbox

# --- Physics ---
RHO_CU_OHM_M = 1.68e-8          # copper resistivity at 20 degC
COPPER_THICKNESS_UM: float | None = None  # None -> stackup, fallback 35.0 with warning
FALLBACK_THICKNESS_UM = 35.0
TEST_CURRENT_A = 1.0            # default injected current (dialog/CLI-selectable)
VIA_PLATING_UM = 18.0           # barrel plating thickness (always plated).
                                # Via capping is NOT modeled: layer-to-layer
                                # the cap (>=15um per fab spec, thinner than
                                # the foil) is parallel to the annular-ring
                                # contact, not in series; in-plane every via
                                # mouth is treated as solid layer-thickness
                                # copper (error bound: see README).
INCLUDE_TH_PADS = True          # plated through-hole pads stitch layers too
SKIN_SIDES = 1                  # skin-effect field config: 1 = plane facing a
                                # return plane (conservative), 2 = isolated foil

# --- Solder / mask-opening buildup ---
INCLUDE_MASK_BUILDUP = False    # OFF by default; dialog-toggleable. Zones on
                                # F.Mask/B.Mask = mask openings that collect
                                # solder on the pour underneath
SOLDER_THICKNESS_UM = 50.0      # solder height over opened copper
SOLDER_RHO_OHM_M = 1.32e-7      # SAC305, ~7.9x copper
BUILDUP_EXTRA_CU_UM = 0.0       # optional user-added copper (busbar/wire
                                # soldered into the opening); dialog-settable

# --- Zone / layer selection ---
INCLUDE_TRACKS = True           # the net's traces (straight + arc tracks)
                                # conduct together with the zone fills;
                                # dialog-toggleable
TRACK_1D_FACTOR = 3.0           # traces narrower than this many grid cells
                                # become exact 1D resistor chains along their
                                # centerline instead of rasterized outlines
                                # (no discretization error in the trace R;
                                # 0 = always rasterize)
LAYER_HINT: str | None = None   # e.g. "F.Cu" to disambiguate candidate fills
ELECTRODE_POS_LAYER = "User.1"  # rectangles on this layer mark V+ contact parts
ELECTRODE_NEG_LAYER = "User.2"  # rectangles on this layer mark V- contact parts
ALWAYS_REFILL = False           # refill zones even if KiCad says they are filled

# --- Solver ---
CONTACT_MODEL = "uniform"       # "uniform": conductor pressed on top injects
                                # orthogonally with uniform surface density
                                # (J ramps across the contact); "equipotential":
                                # ideal bonded lug (Dirichlet). The two bracket
                                # a real contact: R_equi <= R_real <= R_uniform.
SPSOLVE_MAX_UNKNOWNS = 500_000  # above this, AMG-preconditioned CG (pyamg;
                                # Jacobi-CG if pyamg is missing). Direct is
                                # exact and fastest for small grids; measured
                                # at 1.4M unknowns: spsolve 13 s / ~3 GB,
                                # AMG-CG 6 s at a fraction of the memory
AMG_TOL = 1e-10                 # relative residual of the AMG-CG solve
CG_TOL = 1e-8                   # Jacobi-CG fallback (no pyamg)
CG_MAXITER = 50_000             # CG iterations are cheap; large grids need many

# --- Geometry ---
ARC_TOL_FRACTION = 0.5          # arc sagitta tolerance as a fraction of cell size

# --- Plots / output ---
CMAP_POTENTIAL = "viridis"
CMAP_CURRENT = "inferno"
CMAP_POWER = "magma"
POWER_DYNAMIC_RANGE = 1e4       # LogNorm span for the power map (power ~ J^2)
LOG_CURRENT_SCALE = True
CURRENT_DYNAMIC_RANGE = 1e3     # LogNorm vmin = vmax / this
DPI = 150
INTERACTIVE = True              # False -> save PNGs only, never open windows
OUTPUT_DIRNAME = "fill_res_results"