#!/usr/bin/env fontforge
"""
Apply arch cut to uppercase A-Z and digit 2-9.
Arch = planet rising from below. The arc curves UPWARD into the bottom of the glyph.
The cut area is removed (transparent), not filled.
"""
import fontforge
import os
import math

SRC_DIR = "/tmp/aifont_meslo"
DST_DIR = "/tmp/aifont_arch"
os.makedirs(DST_DIR, exist_ok=True)

chars = []
for c in range(ord('A'), ord('Z')+1):
    chars.append(chr(c))
for c in range(ord('0'), ord('9')+1):
    chars.append(chr(c))

# Skip arch for round-bottom characters
skip_arch = set()

WIDTH = 602  # Meslo monospace width

workfont = fontforge.font()
workfont.em = 1000
workfont.encoding = "UnicodeFull"

for g in chars:
    cp = ord(g)
    src = os.path.join(SRC_DIR, g + ".svg")
    if not os.path.exists(src):
        continue

    glyph = workfont.createChar(cp, g)
    glyph.importOutlines(src)
    glyph.width = WIDTH

    if g not in skip_arch:
        bb = glyph.boundingBox()
        xmin, ymin, xmax, ymax = bb
        h = ymax - ymin
        w = xmax - xmin

        # How much of the glyph bottom to cut (15%)
        cut_depth = h * 0.07

        # Large arc radius - the "planet" rising from below
        # Larger radius = gentler curve
        radius = w * 2.5

        # The arc center is below the glyph
        cx = (xmin + xmax) / 2.0
        # Position so the top of the arc reaches cut_depth into the glyph
        cy = ymin - radius + cut_depth

        # We need to intersect the glyph with the area ABOVE the arc.
        # Strategy: create a large clockwise (additive) shape representing
        # "everything above the arc line", then intersect with the glyph.

        # Step 1: Clear glyph, we'll rebuild via intersection
        # Save current contours by using a temp approach

        # Better strategy using fontforge:
        # 1. Create a second glyph with a huge filled area that has the arc as its bottom edge
        # 2. Use intersect to keep only where glyph and mask overlap

        # Create mask glyph: a large rectangle with arc-shaped bottom
        mask_cp = 0xE900
        mask = workfont.createChar(mask_cp, "mask")
        mask.clear()

        margin = 200
        left = xmin - margin
        right = xmax + margin
        top = ymax + margin

        # The arc: we need points along the arc from left to right
        # Arc equation: (x - cx)^2 + (y - cy)^2 = radius^2
        # y = cy + sqrt(radius^2 - (x-cx)^2)  (upper half of circle)

        # Calculate arc endpoints
        def arc_y(x):
            dx = x - cx
            if abs(dx) > radius:
                return ymin
            return cy + math.sqrt(radius * radius - dx * dx)

        # Generate points along the arc
        n_points = 40
        arc_points = []
        for idx in range(n_points + 1):
            x = left + (right - left) * idx / n_points
            y = arc_y(x)
            arc_points.append((x, y))

        pen = mask.glyphPen()
        # Draw clockwise: top-left -> top-right -> arc from right to left -> close
        pen.moveTo((left, top))
        pen.lineTo((right, top))
        # Go down right side to arc start
        pen.lineTo((right, arc_points[-1][1]))
        # Follow arc from right to left (reverse order)
        for idx in range(n_points - 1, -1, -1):
            pen.lineTo(arc_points[idx])
        pen.closePath()
        pen = None

        # Now intersect: keep only the part of glyph inside the mask
        glyph.correctDirection()
        mask.correctDirection()

        # Copy mask into glyph's layer and intersect
        workfont.selection.select(mask_cp)
        workfont.copy()
        workfont.selection.select(cp)
        workfont.pasteInto()
        glyph.intersect()

        # Clean up mask
        mask.clear()

    dst = os.path.join(DST_DIR, g + ".svg")
    glyph.export(dst)
    print("Done: " + g)

print("\nAll done! Results: " + DST_DIR)