const Prefixer = require('./prefixer');
const Browsers = require('./browsers');
const utils = require('./utils');

class Declaration extends Prefixer {

    /**
     * Always true, because we already get prefixer by property name
     */
    check(/* decl */) {
        return true;
    }

    /**
     * Return prefixed version of property
     */
    prefixed(prop, prefix) {
        return prefix + prop;
    }

    /**
     * Return unprefixed version of property
     */
    normalize(prop) {
        return prop;
    }

    /**
     * Check `value`, that it contain other prefixes, rather than `prefix`
     */
    otherPrefixes(value, prefix) {
        for (const other of Browsers.prefixes()) {
            if (other === prefix) {
                continue;
            }
            if (value.indexOf(other) !== -1) {
                return true;
            }
        }
        return false;
    }

    /**
     * Set prefix to declaration
     */
    set(decl, prefix) {
        decl.prop = this.prefixed(decl.prop, prefix);
        return decl;
    }

    /**
     * Should we use visual cascade for prefixes
     */
    needCascade(decl) {
        if (!decl._autoprefixerCascade) {
            decl._autoprefixerCascade =
                this.all.options.cascade !== false &&
                decl.raw('before').indexOf('\n') !== -1;
        }
        return decl._autoprefixerCascade;
    }

    /**
     * Return maximum length of possible prefixed property
     */
    maxPrefixed(prefixes, decl) {
        if (decl._autoprefixerMax) {
            return decl._autoprefixerMax;
        }

        let max = 0;
        for (let prefix of prefixes) {
            prefix = utils.removeNote(prefix);
            if (prefix.length > max) {
                max = prefix.length;
            }
        }
        decl._autoprefixerMax = max;

        return decl._autoprefixerMax;
    }

    /**
     * Calculate indentation to create visual cascade
     */
    calcBefore(prefixes, decl, prefix = '') {
        const max = this.maxPrefixed(prefixes, decl);
        const diff = max - utils.removeNote(prefix).length;

        let before = decl.raw('before');
        if (diff > 0) {
            before += Array(diff).fill(' ').join('');
        }

        return before;
    }

    /**
     * Remove visual cascade
     */
    restoreBefore(decl) {
        const lines = decl.raw('before').split('\n');
        let min = lines[lines.length - 1];

        this.all.group(decl).up((prefixed) => {
            const array = prefixed.raw('before').split('\n');
            const last = array[array.length - 1];
            if (last.length < min.length) {
                min = last;
            }
        });

        lines[lines.length - 1] = min;
        decl.raws.before = lines.join('\n');
    }

    /**
     * Clone and insert new declaration
     */
    insert(decl, prefix, prefixes) {
        const cloned = this.set(this.clone(decl), prefix);
        if (!cloned) return undefined;

        const already = decl.parent.some(
            i => i.prop === cloned.prop && i.value === cloned.value
        );
        if (already) {
            return undefined;
        }

        if (this.needCascade(decl)) {
            cloned.raws.before = this.calcBefore(prefixes, decl, prefix);
        }
        return decl.parent.insertBefore(decl, cloned);
    }

    /**
     * Did this declaration has this prefix above
     */
    isAlready(decl, prefixed) {
        let already = this.all.group(decl).up(i => i.prop === prefixed);
        if (!already) {
            already = this.all.group(decl).down(i => i.prop === prefixed);
        }
        return already;
    }

    /**
     * Clone and add prefixes for declaration
     */
    add(decl, prefix, prefixes, result) {
        const prefixed = this.prefixed(decl.prop, prefix);
        if (this.isAlready(decl, prefixed) ||
            this.otherPrefixes(decl.value, prefix)) {
            return undefined;
        }
        return this.insert(decl, prefix, prefixes, result);
    }

    /**
     * Add spaces for visual cascade
     */
    process(decl, result) {
        if (!this.needCascade(decl)) {
            super.process(decl, result);
            return;
        }

        const prefixes = super.process(decl, result);

        if (!prefixes || !prefixes.length) {
            return;
        }

        this.restoreBefore(decl);
        decl.raws.before = this.calcBefore(prefixes, decl);
    }

    /**
     * Return list of prefixed properties to clean old prefixes
     */
    old(prop, prefix) {
        return [this.prefixed(prop, prefix)];
    }

}

module.exports = Declaration;
