/**
 * STEP.js
 *
 * @author realor
 */

const HEADER_SCHEMA = {}

class STEPFile {
    name = null
    description = null
    schema = null // schema definition

    tags = {}
    references = []
}

class STEPParser {
    schema = null // classes map
    getSchemaTypes = null // called to get schema types
    onEntityCreated = null // called each time an entity is created

    decodeSTEPString(str) {
        return str.replace(/\\X2\\[\dA-F]{4}\\X0\\|\\X\\[\dA-F]{2}/gi, function(match) {
            var code = match.length === 12 ? match.substring(4, 8) : match.substring(3, 5)
            return String.fromCharCode(parseInt(code, 16))
        })
    }

    parse(text) {
        const t0 = Date.now()
        const file = new STEPFile()
        let tags = file.tags
        let references = file.references
        let lineCount = 0

        let builder = null
        let stack = []
        let token = ''
        let tag = null
        let inString = false
        let inComment = false

        for (let i = 0; i < text.length; i++) {
            let ch = text[i]
            if (inString) {
                if (ch === "'") {
                    let nextCh = i < text.length - 1 ? text[i + 1] : null
                    if (nextCh === "'") {
                        // quote '' => '
                        token += "'"
                        i++
                    } else {
                        if (builder) {
                            builder.add(this.decodeSTEPString(token))
                        }
                        token = ''
                        inString = false
                    }
                } else {
                    token += ch
                }
            } else if (inComment) {
                token += ch
                if (token.endsWith('*/')) {
                    inComment = false
                    token = ''
                }
            } // out of string and comment
            else {
                if (ch === "'") {
                    inString = true
                } else if (ch === ' ') {
                    // ignore
                } else if (ch === '(') {
                    let typeName = token.length > 0 ? token.toUpperCase() : 'Array'
                    let schema = tag ? this.schema : HEADER_SCHEMA
                    let newBuilder = new STEPBuilder(typeName, schema)

                    if (builder) {
                        // previous builder
                        stack.push(builder) // save previous builder
                        builder.add(newBuilder.instance)
                    }
                    builder = newBuilder
                    token = ''
                } else if (ch === ',' || ch === ')') {
                    if (builder === null) {
                        console.warn('Parse error in line ' + (lineCount + 1))
                        return null
                    }

                    if (token.length > 0) {
                        if (token === '$') {
                            builder.add(null)
                        } else if ('0123456789-'.indexOf(token[0]) !== -1) {
                            builder.add(parseFloat(token))
                        } else if (token.charAt(0) === '#') {
                            if (builder.instance) {
                                references.push(new STEPReference(builder, token))
                            }
                            builder.add(null)
                        } else {
                            builder.add(token)
                        }
                        token = ''
                    }
                    if (ch === ')') {
                        if (stack.length > 0) {
                            builder = stack.pop()
                        }
                    }
                } else if (ch === ';') {
                    if (tag) {
                        if (builder && builder.instance) {
                            tags[tag] = builder.instance
                            if (this.onEntityCreated) {
                                this.onEntityCreated(builder.instance)
                            }
                        }
                    } // process header elements
                    else {
                        if (builder) {
                            let instance = builder.instance
                            if (instance instanceof FILE_SCHEMA) {
                                file.schema = instance
                                let schemaName = file.schema.Schemas[0]
                                if (this.getSchemaTypes) {
                                    this.schema = this.getSchemaTypes(schemaName)
                                }
                            } else if (instance instanceof FILE_NAME) {
                                file.name = instance
                            } else if (instance instanceof FILE_DESCRIPTION) {
                                file.description = instance
                            }
                        }
                    }
                    token = ''
                    tag = null
                    builder = null
                } else if (ch === '\t') {
                    // ignore
                } else if (ch === '\n') {
                    if (i === 0 || (i > 0 && text[i - 1] !== '\r')) lineCount++
                } else if (ch === '\r') {
                    if (i === 0 || (i > 0 && text[i - 1] !== '\n')) lineCount++
                } else if (ch === '=') {
                    token = token.trim()
                    if (token.indexOf('#') === 0) {
                        tag = token.trim()
                    }
                    token = ''
                } else {
                    token += ch
                    if (token.startsWith('/*')) {
                        inComment = true
                    }
                }
            }
        }

        // dereference references
        for (let i = 0; i < references.length; i++) {
            let reference = references[i]
            let instance = reference.instance
            let referencedInstance = tags[reference.tag] || null
            if (reference.property) {
                instance[reference.property] = referencedInstance
            } // Array
            else {
                let index = reference.index
                instance[index] = referencedInstance
            }
        }
        const t1 = Date.now()
        console.info('STEP File parsed in ' + (t1 - t0) + ' millis.')
        console.info('File contains ' + lineCount + ' lines.')

        return file
    }
}

class STEPBuilder {
    constructor(typeName, schema) {
        this.index = 0
        if (typeName === 'Array') {
            this.instance = []
        } else {
            let cls = schema ? schema[typeName] : HEADER_SCHEMA[typeName]
            if (cls) {
                this.instance = new cls()
                this.properties = Object.getOwnPropertyNames(this.instance)
            } else {
                this.instance = null
                console.warn('Unsupported entity ' + typeName)
            }
        }
    }

    add(element) {
        var instance = this.instance
        if (instance instanceof Array) {
            instance.push(element)
        } else if (instance !== null) {
            instance[this.properties[this.index]] = element
        }
        this.index++
    }
}

class STEPReference {
    constructor(builder, tag) {
        this.instance = builder.instance
        this.index = builder.index
        this.tag = tag // #<number>
        this.property = builder.properties ? builder.properties[builder.index] : null
    }
}

/* STEP header elements */

class FILE_DESCRIPTION {
    Description = null
    ImplementationLevel = null
}

class FILE_NAME {
    Name = null
    TimeStamp = null
    Author = null
    Organization = null
    PreprocessorVersion = null
    Authorization = null
    Other = null
}

class FILE_SCHEMA {
    Schemas = null
}

HEADER_SCHEMA.FILE_DESCRIPTION = FILE_DESCRIPTION
HEADER_SCHEMA.FILE_NAME = FILE_NAME
HEADER_SCHEMA.FILE_SCHEMA = FILE_SCHEMA

export { STEPParser, STEPFile }