parser.js

const postcss = require('postcss')
const gonzales = require('gonzales-pe')

const DEFAULT_RAWS_ROOT = {
    before: ''
}

const DEFAULT_RAWS_RULE = {
    before: '',
    between: ''
}

const DEFAULT_RAWS_DECL = {
    before: '',
    between: '',
    semicolon: false
}

const DEFAULT_COMMENT_DECL = {
    before: ''
}

const SUPPORTED_AT_KEYWORDS = ['media']

class SassParser {
    constructor (input) {
        this.input = input
    }

    parse () {
        try {
            this.node = gonzales.parse(this.input.css, { syntax: 'sass' })
        } catch (error) {
            throw this.input.error(error.message, error.line, 1)
        }
        this.lines = this.input.css.match(/^.*(\r?\n|$)/gm)
        this.root = this.stylesheet(this.node)
    }

    extractSource (start, end) {
        let nodeLines = this.lines.slice(start.line - 1, end.line)

        nodeLines[0] = nodeLines[0].substring(start.column - 1)
        let last = nodeLines.length - 1
        nodeLines[last] = nodeLines[last].substring(0, end.column)

        return nodeLines.join('')
    }

    stylesheet (node) {
        // Create and set parameters for Root node
        let root = postcss.root()
        root.source = {
            start: node.start,
            end: node.end,
            input: this.input
        }
        // Raws for root node
        root.raws = {
            semicolon: DEFAULT_RAWS_ROOT.semicolon,
            before: DEFAULT_RAWS_ROOT.before
        }
        // Store spaces before root (if exist)
        this.raws = {
            before: ''
        }
        node.content.forEach(contentNode => this.process(contentNode, root))
        return root
    }

    process (node, parent) {
        if (this[node.type]) return this[node.type](node, parent) || null
        return null
    }

    ruleset (node, parent) {
        // Loop to find the deepest ruleset node
        this.raws.multiRuleProp = ''

        node.content.forEach(contentNode => {
            switch (contentNode.type) {
                case 'block': {
                    // Create Rule node
                    let rule = postcss.rule()
                    rule.selector = ''
                    // Object to store raws for Rule
                    let ruleRaws = {
                        before: this.raws.before || DEFAULT_RAWS_RULE.before,
                        between: DEFAULT_RAWS_RULE.between
                    }

                    // Variable to store spaces and symbols before declaration property
                    this.raws.before = ''
                    this.raws.comment = false

                    // Look up throw all nodes in current ruleset node
                    node.content
                        .filter(content => content.type === 'block')
                        .forEach(innerContentNode =>
                            this.process(innerContentNode, rule)
                        )

                    if (rule.nodes.length) {
                        // Write selector to Rule
                        rule.selector = this.extractSource(
                            node.start,
                            contentNode.start
                        )
                            .slice(0, -1)
                            .replace(/\s+$/, spaces => {
                                ruleRaws.between = spaces
                                return ''
                            })
                        // Set parameters for Rule node
                        rule.parent = parent
                        rule.source = {
                            start: node.start,
                            end: node.end,
                            input: this.input
                        }
                        rule.raws = ruleRaws
                        parent.nodes.push(rule)
                    }
                    break
                }
                default:
            }
        })
    }

    block (node, parent) {
        // If nested rules exist, wrap current rule in new rule node
        if (this.raws.multiRule) {
            if (this.raws.multiRulePropVariable) {
                this.raws.multiRuleProp = `$${this.raws.multiRuleProp}`
            }
            let multiRule = Object.assign(postcss.rule(), {
                source: {
                    start: {
                        line: node.start.line - 1,
                        column: node.start.column
                    },
                    end: node.end,
                    input: this.input
                },
                raws: {
                    before: this.raws.before || DEFAULT_RAWS_RULE.before,
                    between: DEFAULT_RAWS_RULE.between
                },
                parent,
                selector:
                    (this.raws.customProperty ? '--' : '') +
                    this.raws.multiRuleProp
            })
            parent.push(multiRule)
            parent = multiRule
        }

        this.raws.before = ''

        // Looking for declaration node in block node
        node.content.forEach(contentNode => this.process(contentNode, parent))
        if (this.raws.multiRule) {
            this.raws.beforeMulti = this.raws.before
        }
    }

    declaration (node, parent) {
        let isBlockInside = false
        // Create Declaration node
        let declarationNode = postcss.decl()
        declarationNode.prop = ''

        // Object to store raws for Declaration
        let declarationRaws = Object.assign(declarationNode.raws, {
            before: this.raws.before || DEFAULT_RAWS_DECL.before,
            between: DEFAULT_RAWS_DECL.between,
            semicolon: DEFAULT_RAWS_DECL.semicolon
        })

        this.raws.property = false
        this.raws.betweenBefore = false
        this.raws.comment = false
        // Looking for property and value node in declaration node
        node.content.forEach(contentNode => {
            switch (contentNode.type) {
                case 'customProperty':
                    this.raws.customProperty = true
                // fall through
                case 'property': {
                    /* this.raws.property to detect is property is already defined in current object */
                    this.raws.property = true
                    this.raws.multiRuleProp = contentNode.content[0].content
                    this.raws.multiRulePropVariable =
                        contentNode.content[0].type === 'variable'
                    this.process(contentNode, declarationNode)
                    break
                }
                case 'propertyDelimiter': {
                    if (this.raws.property && !this.raws.betweenBefore) {
                        /* If property is already defined and there's no ':' before it */
                        declarationRaws.between += contentNode.content
                        this.raws.multiRuleProp += contentNode.content
                    } else {
                        /* If ':' goes before property declaration, like :width 100px */
                        this.raws.betweenBefore = true
                        declarationRaws.before += contentNode.content
                        this.raws.multiRuleProp += contentNode.content
                    }
                    break
                }
                case 'space': {
                    declarationRaws.between += contentNode.content
                    break
                }
                case 'value': {
                    // Look up for a value for current property
                    switch (contentNode.content[0].type) {
                        case 'block': {
                            isBlockInside = true
                            // If nested rules exist
                            if (Array.isArray(contentNode.content[0].content)) {
                                this.raws.multiRule = true
                            }
                            this.process(contentNode.content[0], parent)
                            break
                        }
                        case 'variable': {
                            declarationNode.value = '$'
                            this.process(contentNode, declarationNode)
                            break
                        }
                        case 'color': {
                            declarationNode.value = '#'
                            this.process(contentNode, declarationNode)
                            break
                        }
                        case 'number': {
                            if (contentNode.content.length > 1) {
                                declarationNode.value = contentNode.content.join(
                                    ''
                                )
                            } else {
                                this.process(contentNode, declarationNode)
                            }
                            break
                        }
                        case 'parentheses': {
                            declarationNode.value = '('
                            this.process(contentNode, declarationNode)
                            break
                        }
                        default: {
                            this.process(contentNode, declarationNode)
                        }
                    }
                    break
                }
                default:
            }
        })

        if (!isBlockInside) {
            // Set parameters for Declaration node
            declarationNode.source = {
                start: node.start,
                end: node.end,
                input: this.input
            }
            declarationNode.parent = parent
            parent.nodes.push(declarationNode)
        }

        this.raws.before = ''
        this.raws.customProperty = false
        this.raws.multiRuleProp = ''
        this.raws.property = false
    }

    customProperty (node, parent) {
        this.property(node, parent)
        parent.prop = `--${parent.prop}`
    }

    property (node, parent) {
        // Set property for Declaration node
        switch (node.content[0].type) {
            case 'variable': {
                parent.prop += '$'
                break
            }
            case 'interpolation': {
                this.raws.interpolation = true
                parent.prop += '#{'
                break
            }
            default:
        }
        parent.prop += node.content[0].content
        if (this.raws.interpolation) {
            parent.prop += '}'
            this.raws.interpolation = false
        }
    }

    value (node, parent) {
        if (!parent.value) {
            parent.value = ''
        }
        // Set value for Declaration node
        if (node.content.length) {
            node.content.forEach(contentNode => {
                switch (contentNode.type) {
                    case 'important': {
                        parent.raws.important = contentNode.content
                        parent.important = true
                        let match = parent.value.match(/^(.*?)(\s*)$/)
                        if (match) {
                            parent.raws.important =
                                match[2] + parent.raws.important
                            parent.value = match[1]
                        }
                        break
                    }
                    case 'parentheses': {
                        parent.value += contentNode.content.join('') + ')'
                        break
                    }
                    case 'percentage': {
                        parent.value += contentNode.content.join('') + '%'
                        break
                    }
                    default: {
                        if (contentNode.content.constructor === Array) {
                            parent.value += contentNode.content.join('')
                        } else {
                            parent.value += contentNode.content
                        }
                    }
                }
            })
        }
    }

    singlelineComment (node, parent) {
        return this.comment(node, parent, true)
    }

    multilineComment (node, parent) {
        return this.comment(node, parent, false)
    }

    comment (node, parent, inline) {
        // https://github.com/nodesecurity/eslint-plugin-security#detect-unsafe-regex
        // eslint-disable-next-line security/detect-unsafe-regex
        let text = node.content.match(/^(\s*)((?:\S[\S\s]*?)?)(\s*)$/)

        this.raws.comment = true

        let comment = Object.assign(postcss.comment(), {
            text: text[2],
            raws: {
                before: this.raws.before || DEFAULT_COMMENT_DECL.before,
                left: text[1],
                right: text[3],
                inline
            },
            source: {
                start: {
                    line: node.start.line,
                    column: node.start.column
                },
                end: node.end,
                input: this.input
            },
            parent
        })

        if (this.raws.beforeMulti) {
            comment.raws.before += this.raws.beforeMulti
            this.raws.beforeMulti = undefined
        }

        parent.nodes.push(comment)
        this.raws.before = ''
    }

    space (node, parent) {
        // Spaces before root and rule
        switch (parent.type) {
            case 'root': {
                this.raws.before += node.content
                break
            }
            case 'rule': {
                if (this.raws.comment) {
                    this.raws.before += node.content
                } else if (this.raws.loop) {
                    parent.selector += node.content
                } else {
                    this.raws.before = (this.raws.before || '\n') + node.content
                }
                break
            }
            default:
        }
    }

    declarationDelimiter (node) {
        this.raws.before += node.content
    }

    loop (node, parent) {
        let loop = postcss.rule()
        this.raws.comment = false
        this.raws.multiRule = false
        this.raws.loop = true
        loop.selector = ''
        loop.raws = {
            before: this.raws.before || DEFAULT_RAWS_RULE.before,
            between: DEFAULT_RAWS_RULE.between
        }
        if (this.raws.beforeMulti) {
            loop.raws.before += this.raws.beforeMulti
            this.raws.beforeMulti = undefined
        }
        node.content.forEach((contentNode, i) => {
            if (node.content[i + 1] && node.content[i + 1].type === 'block') {
                this.raws.loop = false
            }
            this.process(contentNode, loop)
        })
        parent.nodes.push(loop)
        this.raws.loop = false
    }

    atrule (node, parent) {
        // Skip unsupported @xxx rules
        let supportedNode = node.content[0].content.some(contentNode =>
            SUPPORTED_AT_KEYWORDS.includes(contentNode.content)
        )
        if (!supportedNode) return

        let atrule = postcss.rule()
        atrule.selector = ''
        atrule.raws = {
            before: this.raws.before || DEFAULT_RAWS_RULE.before,
            between: DEFAULT_RAWS_RULE.between
        }
        node.content.forEach((contentNode, i) => {
            if (contentNode.type === 'space') {
                let prevNodeType = node.content[i - 1].type
                switch (prevNodeType) {
                    case 'atkeyword':
                    case 'ident':
                        atrule.selector += contentNode.content
                        break
                    default:
                }
                return
            }
            this.process(contentNode, atrule)
        })
        parent.nodes.push(atrule)
    }

    parentheses (node, parent) {
        parent.selector += '('
        node.content.forEach(contentNode => {
            if (typeof contentNode.content === 'string') {
                parent.selector += contentNode.content
            }

            if (typeof contentNode.content === 'object') {
                contentNode.content.forEach(childrenContentNode => {
                    if (contentNode.type === 'variable') parent.selector += '$'
                    parent.selector += childrenContentNode.content
                })
            }
        })
        parent.selector += ')'
    }

    interpolation (node, parent) {
        parent.selector += '#{'
        node.content.forEach(contentNode => {
            this.process(contentNode, parent)
        })
        parent.selector += '}'
    }

    atkeyword (node, parent) {
        parent.selector += `@${node.content}`
    }

    operator (node, parent) {
        parent.selector += node.content
    }

    variable (node, parent) {
        if (this.raws.loop) {
            parent.selector += `$${node.content[0].content}`
            return
        }
        parent.selector += `$${node.content}`
    }

    ident (node, parent) {
        parent.selector += node.content
    }
}

module.exports = SassParser