import { addEventListener, addMeltEventListener, makeElement, makeElementArray, createElHelpers, disabledAttr, effect, executeCallbacks, generateIds, getElementByMeltId, isBrowser, isHTMLElement, kbd, omit, overridable, snapValueToStep, styleToString, toWritableStores, } from '../../internal/helpers/index.js';
import { derived, writable } from 'svelte/store';
import { withGet } from '../../internal/helpers/withGet.js';
const defaults = {
    defaultValue: [],
    min: 0,
    max: 100,
    step: 1,
    orientation: 'horizontal',
    dir: 'ltr',
    disabled: false,
};
const { name } = createElHelpers('slider');
export const createSlider = (props) => {
    const withDefaults = { ...defaults, ...props };
    const options = toWritableStores(omit(withDefaults, 'value', 'onValueChange', 'defaultValue'));
    const { min, max, step, orientation, dir, disabled } = options;
    const valueWritable = withDefaults.value ?? writable(withDefaults.defaultValue);
    const value = overridable(valueWritable, withDefaults?.onValueChange);
    const isActive = withGet(writable(false));
    const currentThumbIndex = withGet(writable(0));
    const activeThumb = withGet(writable(null));
    const meltIds = generateIds(['root']);
    // Helpers
    const updatePosition = (val, index) => {
        value.update((prev) => {
            if (!prev)
                return [val];
            if (prev[index] === val)
                return prev;
            const newValue = [...prev];
            const direction = newValue[index] > val ? -1 : +1;
            function swap() {
                newValue[index] = newValue[index + direction];
                newValue[index + direction] = val;
                const thumbs = getAllThumbs();
                if (thumbs) {
                    thumbs[index + direction].focus();
                    activeThumb.set({ thumb: thumbs[index + direction], index: index + direction });
                }
            }
            if (direction === -1 && val < newValue[index - 1]) {
                swap();
                return newValue;
            }
            else if (direction === 1 && val > newValue[index + 1]) {
                swap();
                return newValue;
            }
            const $min = min.get();
            const $max = max.get();
            const $step = step.get();
            newValue[index] = snapValueToStep(val, $min, $max, $step);
            return newValue;
        });
    };
    const getAllThumbs = () => {
        const root = getElementByMeltId(meltIds.root);
        if (!root)
            return null;
        return Array.from(root.querySelectorAll('[data-melt-part="thumb"]')).filter((thumb) => isHTMLElement(thumb));
    };
    // States
    const position = derived([min, max], ([$min, $max]) => {
        return (val) => {
            const pos = ((val - $min) / ($max - $min)) * 100;
            return pos;
        };
    });
    const direction = withGet.derived([orientation, dir], ([$orientation, $dir]) => {
        if ($orientation === 'horizontal') {
            return $dir === 'rtl' ? 'rl' : 'lr';
        }
        else {
            return $dir === 'rtl' ? 'tb' : 'bt';
        }
    });
    // Elements
    const root = makeElement(name(), {
        stores: [disabled, orientation, dir],
        returned: ([$disabled, $orientation, $dir]) => {
            return {
                dir: $dir,
                disabled: disabledAttr($disabled),
                'data-disabled': disabledAttr($disabled),
                'data-orientation': $orientation,
                style: $disabled
                    ? undefined
                    : `touch-action: ${$orientation === 'horizontal' ? 'pan-y' : 'pan-x'}`,
                'data-melt-id': meltIds.root,
            };
        },
    });
    const range = makeElement(name('range'), {
        stores: [value, direction, position],
        returned: ([$value, $direction, $position]) => {
            const minimum = $value.length > 1 ? $position(Math.min(...$value) ?? 0) : 0;
            const maximum = 100 - $position(Math.max(...$value) ?? 0);
            const style = {
                position: 'absolute',
            };
            switch ($direction) {
                case 'lr': {
                    style.left = `${minimum}%`;
                    style.right = `${maximum}%`;
                    break;
                }
                case 'rl': {
                    style.right = `${minimum}%`;
                    style.left = `${maximum}%`;
                    break;
                }
                case 'bt': {
                    style.bottom = `${minimum}%`;
                    style.top = `${maximum}%`;
                    break;
                }
                case 'tb': {
                    style.top = `${minimum}%`;
                    style.bottom = `${maximum}%`;
                    break;
                }
            }
            return {
                style: styleToString(style),
            };
        },
    });
    const thumbs = makeElementArray(name('thumb'), {
        stores: [value, position, min, max, disabled, orientation, direction],
        returned: ([$value, $position, $min, $max, $disabled, $orientation, $direction]) => {
            const result = Array.from({ length: $value.length || 1 }, (_, i) => {
                const currentThumb = currentThumbIndex.get();
                if (currentThumb < $value.length) {
                    currentThumbIndex.update((prev) => prev + 1);
                }
                const thumbValue = $value[i];
                const thumbPosition = `${$position(thumbValue)}%`;
                const style = {
                    position: 'absolute',
                };
                switch ($direction) {
                    case 'lr': {
                        style.left = thumbPosition;
                        style.translate = '-50% 0';
                        break;
                    }
                    case 'rl': {
                        style.right = thumbPosition;
                        style.translate = '50% 0';
                        break;
                    }
                    case 'bt': {
                        style.bottom = thumbPosition;
                        style.translate = '0 50%';
                        break;
                    }
                    case 'tb': {
                        style.top = thumbPosition;
                        style.translate = '0 -50%';
                        break;
                    }
                }
                return {
                    role: 'slider',
                    'aria-valuemin': $min,
                    'aria-valuemax': $max,
                    'aria-valuenow': thumbValue,
                    'aria-disabled': disabledAttr($disabled),
                    'aria-orientation': $orientation,
                    'data-melt-part': 'thumb',
                    'data-value': thumbValue,
                    style: styleToString(style),
                    tabindex: $disabled ? -1 : 0,
                };
            });
            return result;
        },
        action: (node) => {
            const unsub = addMeltEventListener(node, 'keydown', (event) => {
                if (disabled.get())
                    return;
                const target = event.currentTarget;
                if (!isHTMLElement(target))
                    return;
                const thumbs = getAllThumbs();
                if (!thumbs?.length)
                    return;
                const index = thumbs.indexOf(target);
                currentThumbIndex.set(index);
                if (![
                    kbd.ARROW_LEFT,
                    kbd.ARROW_RIGHT,
                    kbd.ARROW_UP,
                    kbd.ARROW_DOWN,
                    kbd.HOME,
                    kbd.END,
                ].includes(event.key)) {
                    return;
                }
                event.preventDefault();
                const $min = min.get();
                const $max = max.get();
                const $step = step.get();
                const $value = value.get();
                const $orientation = orientation.get();
                const $direction = direction.get();
                const thumbValue = $value[index];
                switch (event.key) {
                    case kbd.HOME: {
                        updatePosition($min, index);
                        break;
                    }
                    case kbd.END: {
                        updatePosition($max, index);
                        break;
                    }
                    case kbd.ARROW_LEFT: {
                        if ($orientation !== 'horizontal')
                            break;
                        if (event.metaKey) {
                            const newValue = $direction === 'rl' ? $max : $min;
                            updatePosition(newValue, index);
                        }
                        else if ($direction === 'rl' && thumbValue < $max) {
                            updatePosition(thumbValue + $step, index);
                        }
                        else if ($direction === 'lr' && thumbValue > $min) {
                            updatePosition(thumbValue - $step, index);
                        }
                        break;
                    }
                    case kbd.ARROW_RIGHT: {
                        if ($orientation !== 'horizontal')
                            break;
                        if (event.metaKey) {
                            const newValue = $direction === 'rl' ? $min : $max;
                            updatePosition(newValue, index);
                        }
                        else if ($direction === 'rl' && thumbValue > $min) {
                            updatePosition(thumbValue - $step, index);
                        }
                        else if ($direction === 'lr' && thumbValue < $max) {
                            updatePosition(thumbValue + $step, index);
                        }
                        break;
                    }
                    case kbd.ARROW_UP: {
                        if (event.metaKey) {
                            const newValue = $direction === 'tb' ? $min : $max;
                            updatePosition(newValue, index);
                        }
                        else if ($direction === 'tb' && thumbValue > $min) {
                            updatePosition(thumbValue - $step, index);
                        }
                        else if ($direction !== 'tb' && thumbValue < $max) {
                            updatePosition(thumbValue + $step, index);
                        }
                        break;
                    }
                    case kbd.ARROW_DOWN: {
                        if (event.metaKey) {
                            const newValue = $direction === 'tb' ? $max : $min;
                            updatePosition(newValue, index);
                        }
                        else if ($direction === 'tb' && thumbValue < $max) {
                            updatePosition(thumbValue + $step, index);
                        }
                        else if ($direction !== 'tb' && thumbValue > $min) {
                            updatePosition(thumbValue - $step, index);
                        }
                        break;
                    }
                }
            });
            return {
                destroy: unsub,
            };
        },
    });
    const ticks = makeElementArray(name('tick'), {
        stores: [value, min, max, step, direction],
        returned: ([$value, $min, $max, $step, $direction]) => {
            const difference = $max - $min;
            // min = 0, max = 8, step = 3:
            // ----------------------------
            // 0, 3, 6
            // (8 - 0) / 3 = 2.666... = 3 ceiled
            let count = Math.ceil(difference / $step);
            // min = 0, max = 9, step = 3:
            // ---------------------------
            // 0, 3, 6, 9
            // (9 - 0) / 3 = 3
            // We need to add 1 because `difference` is a multiple of `step`.
            if (difference % $step == 0) {
                count++;
            }
            return Array.from({ length: count }, (_, i) => {
                // The track is divided into sections of ratio `step / (max - min)`
                const tickPosition = `${i * ($step / ($max - $min)) * 100}%`;
                // Offset each tick by -50% to center it, except the first and last ticks.
                // The first tick is already positioned at the start of the slider.
                // The last tick is offset by -100% to prevent it from being rendered outside.
                const isFirst = i === 0;
                const isLast = i === count - 1;
                const offsetPercentage = isFirst ? 0 : isLast ? -100 : -50;
                const style = {
                    position: 'absolute',
                };
                switch ($direction) {
                    case 'lr': {
                        style.left = tickPosition;
                        style.translate = `${offsetPercentage}% 0`;
                        break;
                    }
                    case 'rl': {
                        style.right = tickPosition;
                        style.translate = `${-offsetPercentage}% 0`;
                        break;
                    }
                    case 'bt': {
                        style.bottom = tickPosition;
                        style.translate = `0 ${-offsetPercentage}%`;
                        break;
                    }
                    case 'tb': {
                        style.top = tickPosition;
                        style.translate = `0 ${offsetPercentage}%`;
                        break;
                    }
                }
                const tickValue = $min + i * $step;
                const bounded = $value.length === 1
                    ? tickValue <= $value[0]
                    : $value[0] <= tickValue && tickValue <= $value[$value.length - 1];
                return {
                    'data-bounded': bounded ? true : undefined,
                    'data-value': tickValue,
                    style: styleToString(style),
                };
            });
        },
    });
    // Effects
    effect([root, min, max, disabled, orientation, direction, step], ([$root, $min, $max, $disabled, $orientation, $direction, $step]) => {
        if (!isBrowser || $disabled)
            return;
        const applyPosition = (clientXY, activeThumbIdx, start, end) => {
            const percent = (clientXY - start) / (end - start);
            const val = percent * ($max - $min) + $min;
            if (val < $min) {
                updatePosition($min, activeThumbIdx);
            }
            else if (val > $max) {
                updatePosition($max, activeThumbIdx);
            }
            else {
                const step = $step;
                const min = $min;
                const currentStep = Math.floor((val - min) / step);
                const midpointOfCurrentStep = min + currentStep * step + step / 2;
                const midpointOfNextStep = min + (currentStep + 1) * step + step / 2;
                const newValue = val >= midpointOfCurrentStep && val < midpointOfNextStep
                    ? (currentStep + 1) * step + min
                    : currentStep * step + min;
                if (newValue <= $max) {
                    updatePosition(newValue, activeThumbIdx);
                }
            }
        };
        const getClosestThumb = (e) => {
            const thumbs = getAllThumbs();
            if (!thumbs)
                return;
            thumbs.forEach((thumb) => thumb.blur());
            const distances = thumbs.map((thumb) => {
                if ($orientation === 'horizontal') {
                    const { left, right } = thumb.getBoundingClientRect();
                    return Math.abs(e.clientX - (left + right) / 2);
                }
                else {
                    const { top, bottom } = thumb.getBoundingClientRect();
                    return Math.abs(e.clientY - (top + bottom) / 2);
                }
            });
            const thumb = thumbs[distances.indexOf(Math.min(...distances))];
            const index = thumbs.indexOf(thumb);
            return { thumb, index };
        };
        const pointerMove = (e) => {
            if (!isActive.get())
                return;
            e.preventDefault();
            e.stopPropagation();
            const sliderEl = getElementByMeltId($root['data-melt-id']);
            const closestThumb = activeThumb.get();
            if (!sliderEl || !closestThumb)
                return;
            closestThumb.thumb.focus();
            const { left, right, top, bottom } = sliderEl.getBoundingClientRect();
            switch ($direction) {
                case 'lr': {
                    applyPosition(e.clientX, closestThumb.index, left, right);
                    break;
                }
                case 'rl': {
                    applyPosition(e.clientX, closestThumb.index, right, left);
                    break;
                }
                case 'bt': {
                    applyPosition(e.clientY, closestThumb.index, bottom, top);
                    break;
                }
                case 'tb': {
                    applyPosition(e.clientY, closestThumb.index, top, bottom);
                    break;
                }
            }
        };
        const pointerDown = (e) => {
            if (e.button !== 0)
                return;
            const sliderEl = getElementByMeltId($root['data-melt-id']);
            const closestThumb = getClosestThumb(e);
            if (!closestThumb || !sliderEl)
                return;
            const target = e.target;
            if (!isHTMLElement(target) || !sliderEl.contains(target)) {
                return;
            }
            e.preventDefault();
            activeThumb.set(closestThumb);
            closestThumb.thumb.focus();
            isActive.set(true);
            pointerMove(e);
        };
        const pointerUp = () => {
            isActive.set(false);
        };
        const unsub = executeCallbacks(addEventListener(document, 'pointerdown', pointerDown), addEventListener(document, 'pointerup', pointerUp), addEventListener(document, 'pointerleave', pointerUp), addEventListener(document, 'pointermove', pointerMove));
        return () => {
            unsub();
        };
    });
    effect([step, min, max, value], function fixValue([$step, $min, $max, $value]) {
        const isValidValue = (v) => {
            const snappedValue = snapValueToStep(v, $min, $max, $step);
            return snappedValue === v;
        };
        const gcv = (v) => {
            return snapValueToStep(v, $min, $max, $step);
        };
        if ($value.some((v) => !isValidValue(v))) {
            value.update((prev) => {
                return prev.map(gcv);
            });
        }
    });
    return {
        elements: {
            root,
            thumbs,
            range,
            ticks,
        },
        states: {
            value,
        },
        options,
    };
};