links_count=6; // [1..20]
include_terminal=true; // [true,false]
export=3; // [0:6]

MODEL_DEMO=0;
MODEL_LINKS=1;
MODEL_CLIP_A=2;
MODEL_CLIP_B=3;
MODEL_CLIP_RATCHETING=4;
MODEL_CLIP_RATCHETING_A=5;
MODEL_CLIP_RATCHETING_B=6;

//validation=1;
VALIDATE_INTERSECTION=1;

//xray=1;

use <BOSL/transforms.scad>
use <BOSL/shapes.scad>
include <BOSL/constants.scad>

function is_not_export() = is_undef(export) || export == 0;
function is_export() = !is_not_export();
function is_model_strict(m) = is_export() && export == m;
function is_model(m) = is_not_export() || export == m;

function get_link_segment_size() = [15, 30, 5];
function get_link_pin_diameter() = 2;
function get_link_socket_slack() = [1, 4, 1];
function get_link_joiner_arm_size() = [get_link_segment_size().x - 2, 3, segment_size.z];
function get_link_socket_size() = [get_link_segment_size().z,
        get_link_segment_size().y - get_link_joiner_arm_size().y*2,
        get_link_segment_size().z];

function get_link_clip_size() = [get_link_pin_diameter()*5, get_link_segment_size().y - 5, get_link_segment_size().z];

echo("===============================");
echo(str("Strap length: ", (links_count * get_link_segment_size().x), " mm"));
echo("===============================");

assert(get_link_segment_size().x >= 10, "Link segment is too short.");
assert(get_link_segment_size().z >= (get_link_pin_diameter() + get_link_socket_slack().z + 1), "Link segment is too thin.");

module link(terminal=false) {
    segment_size=get_link_segment_size();
    module pin() {
        h=segment_size.y;
        d=get_link_pin_diameter();
        back(h/2) xrot(90) cylinder(h=h, d=d, $fn=$preview ? 10 : 30);
    }
    module pin_socket_area() {
        h=segment_size.y-get_link_socket_slack().y;
        d=segment_size.z;
        back(h/2) xrot(90) cylinder(h=h, d=d, $fn=$preview ? 10 : 30);
    }
    module pin_socket() {
        difference() {
            pin_socket_area();
            scaleup = [
                ((get_link_pin_diameter() + get_link_socket_slack().x) / get_link_pin_diameter()),
                ((get_link_pin_diameter() + get_link_socket_slack().y) / get_link_pin_diameter()),
                ((get_link_pin_diameter() + get_link_socket_slack().z) / get_link_pin_diameter())
            ];
            scale(scaleup) pin();
        }
    }
    module joiner() {
        gap=2;
        arm_size=get_link_joiner_arm_size();
        module arm() {
            fwd(segment_size.y/2 + arm_size.y/2 - 1) right(arm_size.x/2 - 1) cuboid(arm_size, fillet=1, edges=EDGES_FRONT + EDGES_Y_ALL);
        }
        module armFront() {
            arm();
        }
        module armBack() {
            scale([1, -1, 1]) arm();
        }
        module armJoiner() {
            joiner_size=[arm_size.x-get_link_socket_size().x, segment_size.y, segment_size.z];
            right(joiner_size.x/2 + get_link_socket_size().x/2 + gap) cuboid(joiner_size, fillet=1, edges=EDGES_Z_ALL + EDGES_BOTTOM);
        }
        module socketJoiner() {
            joiner_size=[segment_size.x-get_link_socket_size().x+get_link_socket_size().x*0.2,
                segment_size.y-4,
                segment_size.z];
            difference() {
                right(joiner_size.x/2 + 4.5) cuboid(joiner_size, fillet=1, edges=EDGES_Z_ALL + EDGES_BOTTOM);
                right(segment_size.x) scale([1, 2, 1]) pin_socket_area();
            }
        }
        module terminalArm() {
            left(5) {
                shift=arm_size.x - get_link_pin_diameter();
                right(segment_size.x + shift + gap/2) pin();
                right(segment_size.x + gap/2) {
                   armFront();
                   armBack();
                }
                right(arm_size.x - get_link_socket_size().x + gap) armJoiner();
            }
        }
        armFront();
        armBack();
        armJoiner();
        if (terminal) {
            terminalArm();
        } else {
            socketJoiner();
        }
    }
    
    pin();
    joiner();
    if (!terminal) {
        right(segment_size.x) pin_socket();
    }
}

module clip() {
    socket_size=get_link_socket_size();
    clip_size=get_link_clip_size();
    pin_diam=get_link_pin_diameter();
    slot_slack=get_link_socket_slack();
    size=[clip_size.x+socket_size.x, clip_size.y, clip_size.z];
    slot_size=[clip_size.x+slot_slack.x, size.y+1, pin_diam+slot_slack.z];
    entry_size=[slot_size.x, clip_size.y+1, clip_size.z];
    entry_pos=[0, 0, 1.5];
    
    module socket_area() {
        $fn=$preview? 10 : 20;
        xrot(90) down(size.y/2) cylinder(d=size.z, h=size.y);
    }
    module socket_cutout() {
        $fn=$preview? 10 : 20;
        xrot(90) down(slot_size.y/2) cylinder(d=slot_size.z, h=slot_size.y);
    }
    module cover() {
        translate(entry_pos) cube(entry_size, center=true);
    }
    module joiner(groove) {
        slack=groove?0.5:0;
        joiner_size=[entry_size.x-6+slack, entry_size.y-6+slack, entry_size.z-4+slack];
        joiner_pos=[entry_pos.x, entry_pos.y, entry_pos.z - entry_size.z/2];
        translate(joiner_pos) cube(joiner_size, center=true);
    }
    
    module model() {
        difference() {
            union() {
                right(clip_size.x/2) socket_area();
                left(clip_size.x/2) socket_area();
                cube(clip_size, center=true);
            }
            right(clip_size.x/2) socket_cutout();
            left(clip_size.x/2) socket_cutout();
        }
    }
    
    right(clip_size.x/2)
    if (is_model(MODEL_CLIP_A)) {
        difference() {
            model();
            cover();
        }
        joiner(groove=false);
    } else if (is_model(MODEL_CLIP_B)) {
        difference() {
            intersection() {
                model();
                cover();
            }
            joiner(groove=true);
        }
    }
}

module clip_ratcheting(ratchet_length=30) {
    socket_size=get_link_socket_size();
    clip_size=get_link_clip_size();
    pin_diam=get_link_pin_diameter();
    slot_slack=get_link_socket_slack();
    size=[clip_size.x+socket_size.x, clip_size.y, clip_size.z];
    slot_size=[clip_size.x+slot_slack.x + 0.2, size.y+1, pin_diam+slot_slack.z];
    entry_size=[slot_size.x-5, clip_size.y+1, clip_size.z];
    //right(clip_size.x/2)
    module hook() {
        intersection() {
            difference() {
                cuboid(size, fillet=1);
                cuboid(slot_size, fillet=1);
                up(entry_size.z/2) cube(entry_size, center=true);
            }
            translate([0, -50, -50]) cube([100, 100, 100]);
        }
    }
    module hookRight() {
        hook();
    }
    module hookLeft() {
        scale([-1, 1, 1]) hook();
    }
    wall=2;
    tooth_size=[4, 3, 3];
    module tooth() {
        s=[tooth_size.x, tooth_size.z, tooth_size.y];
        up(tooth_size.z/2) xrot(-90) right_triangle(s);
    }
    module teethFwd() {
        tooth_count = ratchet_length/tooth_size.x;
        fwd((clip_size.y-wall*2)/2)
        right(ratchet_length/2) {
            for (i=[1:tooth_count]) {
                left(i*tooth_size.x) tooth();
            }
            cap_size=[ratchet_length, tooth_size.y, 1];
            up(tooth_size.z/2 + cap_size.z/2) left(cap_size.x/2) back(tooth_size.y/2) {
                difference() {
                    cube(cap_size, center=true);
                    translate([0.1, 0.1, 0]) back(tooth_size.y/2) right(ratchet_length/2) zrot(180) tooth();
                }
            }
        }
    }
    module teethBack() {
        scale([1, -1, 1]) teethFwd();
    }
    module ratchetLeft() {
        right(ratchet_length/2) {
            difference() {
                cube([ratchet_length, clip_size.y, clip_size.z], center=true);
                up(wall/2) cube([ratchet_length, clip_size.y-wall*2, clip_size.z], center=true);
                right(ratchet_length/2+1) {
                    slideRailGuide(groove=true);
                    scale([1,-1,1]) slideRailGuide(groove=true);
                }
            }
            teethFwd();
            teethBack();
        }
    }
    ratchet_tooth_count=2;
    ratchet_wall=2.5;
    ratchet_slack=0.3;
    rail_slack=0.2;
    ratchet_tooth_scale_z=0.8;
    module ratchetTeethFront() {
        module ratchetButton() {
            size=[8,wall*4,4];
            up(size.z+1) fwd(wall*2 - ratchet_wall) cuboid(size, fillet=1, edges=EDGES_FRONT);
            up(2) back(ratchet_wall/2) cube([size.x, ratchet_wall, tooth_size.z*ratchet_tooth_scale_z + size.z], center=true);
        }
        fwd((clip_size.y-wall*2)/2 - tooth_size.y - ratchet_slack)
        left(ratchet_length) {
            for (i=[0:ratchet_tooth_count-1]) {
               right(i*tooth_size.x) scale([-1,-1*(1-i/5),ratchet_tooth_scale_z]) tooth();
            }
            ratchetButton();
        }
        
        module ratchetWall() {
            up(tooth_size.z/2) left(ratchet_length/2 + wall - wall/2) fwd(clip_size.y/2-wall-tooth_size.y-ratchet_wall/2 - ratchet_slack)
            down(wall/2+0.5) cube([ratchet_length + wall, ratchet_wall, tooth_size.z*ratchet_tooth_scale_z], center=true);
        }
        ratchetWall();
    }
    module ratchetTeethBack() {
        scale([1,-1,1]) ratchetTeethFront();
    }
    module ratchetRight() {
        left(wall) cube([wall*2, clip_size.y + rail_slack*2, clip_size.z], center=true);
        
        ratchetTeethFront();
        ratchetTeethBack();
    }
    module slideRailGuide(groove) {
        size=[ratchet_length, wall, wall];
        fwd(clip_size.y/2 + rail_slack)
        left(size.x/2) scale(groove?1.5:1) cuboid(size, fillet=0.5);
    }
    module slideRailLeft() {
        size=[ratchet_length, clip_size.y/2 - ratchet_wall*2 - wall/2 - ratchet_slack - tooth_size.y, clip_size.z];
        right(size.x/2) cube(size, center=true);
    }
    module slideRailRight() {
        size=[ratchet_length + 3, wall*1.5, clip_size.z];
        module railFront() {
            fwd(clip_size.y/2 + size.y/2 + rail_slack) left(size.x/2)
            cuboid(size, fillet=1, edges=EDGES_FRONT);
            slideRailGuide(groove=false);
        }
        module railBack() {
            scale([1, -1, 1]) railFront();
        }
        railFront();
        railBack();
    }
    
    if (is_model(MODEL_CLIP_RATCHETING_A) || is_model(MODEL_CLIP_RATCHETING)) {
        left(ratchet_length + wall + 1) {
            hookLeft();
            left(0.1) {
                ratchetLeft();
                slideRailLeft();
            }
        }
    }
    if (is_model(MODEL_CLIP_RATCHETING_B) || is_model(MODEL_CLIP_RATCHETING)) {
        ratchetRight();
        hookRight();
        slideRailRight();
    }
}

// Export / Demo / Validation:
segment_size=get_link_segment_size();
if (!is_undef(validation)) {
    if (validation==VALIDATE_INTERSECTION) {
        intersection() {
            right(0*segment_size.x) link();
            right(1*segment_size.x) link();
        }
        intersection() {
            right(1*segment_size.x) link();
            right(2*segment_size.x) link();
        }
    }
} else {
    intersection () {
        if (!is_undef(xray)) {
            down(50) cube([100, 100, 100], center=true);
        }
        union() {
            if (is_model(MODEL_CLIP_A) || is_model(MODEL_CLIP_B)) {
                left(get_link_clip_size().x) clip();
            }
            if (is_model(MODEL_CLIP_RATCHETING) || is_model(MODEL_CLIP_RATCHETING_A) || is_model(MODEL_CLIP_RATCHETING_B)) {
                left(get_link_clip_size().x) clip_ratcheting();
            }
            if (is_model(MODEL_LINKS)) for (i = [0:links_count-1]) {
                terminal=(i==links_count-1) && include_terminal;
                right(i*segment_size.x) link(terminal=terminal);
            }
        }
    }
}