import type { ChannelBias } from "@/content/rift-page-profiles";

export const RIFT_VIEWBOX = { w: 800, h: 1200 } as const;

/** Outer bounds of central meandering rift (vertical flow) */
export const RIFT_CHANNEL_OUTER_LEFT =
  "M 380 1180 C 360 1020, 340 880, 320 760 S 300 620, 310 480 S 330 340, 350 200 S 370 80, 400 40";
export const RIFT_CHANNEL_OUTER_RIGHT =
  "M 420 1180 C 440 1020, 460 880, 480 760 S 500 620, 490 480 S 470 340, 450 200 S 430 80, 400 40";

/** Inner tributary / erosion lines inside channel */
export const RIFT_CHANNEL_INNER = [
  "M 400 1150 C 395 980, 405 820, 398 680 S 402 520, 408 360 S 404 180, 400 60",
  "M 400 1100 C 388 920, 412 740, 395 580 S 410 420, 402 260 S 406 100, 400 50",
  "M 400 1050 C 402 880, 396 710, 400 550 S 398 390, 404 230 S 400 80, 400 45",
  "M 400 1000 Q 385 800, 415 600 T 400 200",
] as const;

/** Smooth major contours — widely spaced */
export const CONTOUR_MAJOR = [
  "M 40 200 C 120 180, 200 220, 280 190 S 400 160, 520 200 S 640 170, 760 210",
  "M 60 320 C 180 300, 300 340, 420 310 S 540 280, 660 320 S 740 290, 760 310",
  "M 30 440 C 160 420, 280 460, 400 430 S 520 400, 640 440 S 720 410, 770 430",
  "M 50 560 C 200 540, 340 580, 480 550 S 600 520, 680 560 S 750 530, 770 550",
  "M 40 680 C 180 660, 320 700, 460 670 S 580 640, 700 680 S 760 650, 770 670",
  "M 55 800 C 220 780, 360 820, 500 790 S 620 760, 720 800 S 760 770, 770 790",
  "M 35 920 C 200 900, 350 940, 500 910 S 640 880, 720 920 S 760 890, 770 910",
  "M 45 1040 C 190 1020, 340 1060, 490 1030 S 630 1000, 710 1040 S 760 1010, 770 1030",
] as const;

/** Terrace / tight contours — one flank (right-biased in default coords) */
export const CONTOUR_MINOR = [
  "M 480 180 L 495 200 L 490 220 L 505 240 L 498 260 L 512 280 L 505 300",
  "M 500 340 L 515 355 L 508 375 L 522 395 L 515 415 L 528 435 L 520 455",
  "M 510 500 L 525 518 L 518 538 L 532 558 L 525 578 L 538 598 L 530 618",
  "M 520 660 L 535 678 L 528 698 L 542 718 L 535 738 L 548 758 L 540 778",
  "M 515 820 L 530 838 L 523 858 L 537 878 L 530 898 L 543 918 L 535 938",
  "M 120 240 L 105 258 L 112 276 L 98 294 L 105 312 L 92 330",
  "M 110 380 L 95 398 L 102 416 L 88 434 L 95 452 L 82 470",
  "M 100 520 L 85 538 L 92 556 L 78 574 L 85 592 L 72 610",
] as const;

/** Stratum lines for pitch / program layers */
export const STRATUM_LINES = [
  "M 80 400 L 720 400",
  "M 100 480 L 700 480",
  "M 120 560 L 680 560",
  "M 140 640 L 660 640",
  "M 160 720 L 640 720",
] as const;

export function getChannelTransform(bias: ChannelBias): string {
  switch (bias) {
    case "left":
      return "translate(-8%, 0)";
    case "right":
      return "translate(8%, 0)";
    default:
      return "translate(0, 0)";
  }
}

export function contourOpacity(
  density: "low" | "medium" | "high",
  kind: "major" | "minor"
): number {
  const base = kind === "major" ? 0.14 : 0.22;
  const mult = density === "low" ? 0.7 : density === "high" ? 1.25 : 1;
  return Math.min(0.45, base * mult);
}