tool/writer/LayoutBinderWriter.kt

/*
 * Copyright (C) 2015 The Android Open Source Project
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *      http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.databinding.tool.writer

import android.databinding.tool.LayoutBinder
import android.databinding.tool.expr.Expr
import kotlin.properties.Delegates
import android.databinding.tool.ext.joinToCamelCaseAsVar
import android.databinding.tool.BindingTarget
import android.databinding.tool.expr.IdentifierExpr
import android.databinding.tool.util.Log
import java.util.BitSet
import android.databinding.tool.expr.ExprModel
import java.util.Arrays
import android.databinding.tool.expr.BitShiftExpr
import android.databinding.tool.expr.TernaryExpr
import android.databinding.tool.expr.FieldAccessExpr
import android.databinding.tool.expr.ComparisonExpr
import android.databinding.tool.expr.GroupExpr
import android.databinding.tool.expr.InstanceOfExpr
import android.databinding.tool.expr.MathExpr
import android.databinding.tool.expr.MethodCallExpr
import android.databinding.tool.expr.StaticIdentifierExpr
import android.databinding.tool.expr.SymbolExpr
import android.databinding.tool.expr.UnaryExpr
import android.databinding.tool.ext.androidId
import android.databinding.tool.ext.lazy
import android.databinding.tool.ext.br
import android.databinding.tool.expr.ResourceExpr
import android.databinding.tool.expr.BracketExpr
import android.databinding.tool.reflection.Callable
import android.databinding.tool.expr.CastExpr
import android.databinding.tool.reflection.ModelAnalyzer
import java.util.ArrayList
import java.util.HashMap

fun String.stripNonJava() = this.split("[^a-zA-Z0-9]").map{ it.trim() }.joinToCamelCaseAsVar()

enum class Scope {
    FIELD
    METHOD
    FLAG
    EXECUTE_PENDING_METHOD
    CONSTRUCTOR_PARAM
}

class ExprModelExt {
    val usedFieldNames = hashMapOf<Scope, MutableSet<String>>();
    {
        Scope.values().forEach { usedFieldNames[it] = hashSetOf<String>() }
    }
    val localizedFlags = arrayListOf<FlagSet>()

    fun localizeFlag(set : FlagSet, name:String) : FlagSet {
        localizedFlags.add(set)
        val result = getUniqueName(name, Scope.FLAG)
        set.setLocalName(result)
        return set
    }

    fun getUniqueName(base : String, scope : Scope) : String {
        var candidate = base
        var i = 0
        while (usedFieldNames[scope].contains(candidate)) {
            i ++
            candidate = base + i
        }
        usedFieldNames[scope].add(candidate)
        return candidate
    }
}

val ExprModel.ext by Delegates.lazy { target : ExprModel ->
    ExprModelExt()
}

fun ExprModel.getUniqueFieldName(base : String) : String = ext.getUniqueName(base, Scope.FIELD)
fun ExprModel.getUniqueMethodName(base : String) : String = ext.getUniqueName(base, Scope.METHOD)
fun ExprModel.getUniqueFlagName(base : String) : String = ext.getUniqueName(base, Scope.FLAG)
fun ExprModel.getConstructorParamName(base : String) : String = ext.getUniqueName(base, Scope.CONSTRUCTOR_PARAM)

fun ExprModel.localizeFlag(set : FlagSet, base : String) : FlagSet = ext.localizeFlag(set, base)

// not necessarily unique. Uniqueness is solved per scope
val BindingTarget.readableName by Delegates.lazy { target: BindingTarget ->
    if (target.getId() == null) {
        "boundView" + indexFromTag(target.getTag())
    } else {
        target.getId().androidId().stripNonJava()
    }
}

fun BindingTarget.superConversion(variable : String) : String {
    if (getResolvedType() != null && getResolvedType().extendsViewStub()) {
        return "new android.databinding.ViewStubProxy((android.view.ViewStub) ${variable})"
    } else {
        return "(${interfaceType}) ${variable}"
    }
}

val BindingTarget.fieldName : String by Delegates.lazy { target : BindingTarget ->
    val name : String
    if (target.getId() == null) {
        name = "m${target.readableName}"
    } else {
        name = target.readableName
    }
    target.getModel().getUniqueFieldName(name)
}

val BindingTarget.androidId by Delegates.lazy { target : BindingTarget ->
    "R.id.${target.getId().androidId()}"
}

val BindingTarget.interfaceType by Delegates.lazy { target : BindingTarget ->
    if (target.getResolvedType() != null && target.getResolvedType().extendsViewStub()) {
        "android.databinding.ViewStubProxy"
    } else {
        target.getInterfaceType()
    }
}

val BindingTarget.constructorParamName by Delegates.lazy { target : BindingTarget ->
    target.getModel().getConstructorParamName(target.readableName)
}

// not necessarily unique. Uniqueness is decided per scope
val Expr.readableName by Delegates.lazy { expr : Expr ->
    val stripped = "${expr.getUniqueKey().stripNonJava()}"
    Log.d { "readableUniqueName for [${System.identityHashCode(expr)}] ${expr.getUniqueKey()} is $stripped" }
    stripped
}

val Expr.fieldName by Delegates.lazy { expr : Expr ->
    expr.getModel().getUniqueFieldName("m${expr.readableName.capitalize()}")
}

val Expr.executePendingLocalName by Delegates.lazy { expr : Expr ->
    if(expr.isVariable()) expr.fieldName else "${expr.getModel().ext.getUniqueName(expr.readableName, Scope.EXECUTE_PENDING_METHOD)}"
}

val Expr.setterName by Delegates.lazy { expr : Expr ->
    expr.getModel().getUniqueMethodName("set${expr.readableName.capitalize()}")
}

val Expr.onChangeName by Delegates.lazy { expr : Expr ->
    expr.getModel().getUniqueMethodName("onChange${expr.readableName.capitalize()}")
}

val Expr.getterName by Delegates.lazy { expr : Expr ->
    expr.getModel().getUniqueMethodName("get${expr.readableName.capitalize()}")
}

val Expr.dirtyFlagName by Delegates.lazy { expr : Expr ->
    expr.getModel().getUniqueFlagName("sFlag${expr.readableName.capitalize()}")
}


fun Expr.toCode(full : Boolean = false) : KCode {
    val it = this
    if (isDynamic() && !full) {
        return kcode(executePendingLocalName)
    }
    return when (it) {
        is ComparisonExpr -> kcode("") {
            app("", it.getLeft().toCode())
            app(it.getOp())
            app("", it.getRight().toCode())
        }
        is InstanceOfExpr -> kcode("") {
            app("", it.getExpr().toCode())
            app(" instanceof ")
            app("", it.getType().toJavaCode())
        }
        is FieldAccessExpr -> kcode("") {
            app("", it.getChild().toCode())
            if (it.getGetter().type == Callable.Type.FIELD) {
                app(".", it.getGetter().name)
            } else {
                app(".", it.getGetter().name).app("()")
            }
        }
        is GroupExpr -> kcode("(").app("", it.getWrapped().toCode()).app(")")
        is StaticIdentifierExpr -> kcode(it.getResolvedType().toJavaCode())
        is IdentifierExpr -> kcode(it.executePendingLocalName)
        is MathExpr -> kcode("") {
            app("", it.getLeft().toCode())
            app(it.getOp())
            app("", it.getRight().toCode())
        }
        is UnaryExpr -> kcode("") {
            app(it.getOp(), it.getExpr().toCode())
        }
        is BitShiftExpr -> kcode("") {
            app("", it.getLeft().toCode())
            app(it.getOp())
            app("", it.getRight().toCode())
        }
        is MethodCallExpr -> kcode("") {
            app("", it.getTarget().toCode())
            app(".", it.getGetter().name)
            app("(")
            var first = true
            it.getArgs().forEach {
                apps(if (first) "" else ",", it.toCode())
                first = false
            }
            app(")")
        }
        is SymbolExpr -> kcode(it.getText()) // TODO
        is TernaryExpr -> kcode("") {
            app("", it.getPred().toCode())
            app("?", it.getIfTrue().toCode())
            app(":", it.getIfFalse().toCode())
        }
        is ResourceExpr -> kcode("") {
            app("", it.toJava())
        }
        is BracketExpr -> kcode("") {
            app("", it.getTarget().toCode())
            val bracketType = it.getAccessor();
            when (bracketType) {
                BracketExpr.BracketAccessor.ARRAY -> {
                    app("[", it.getArg().toCode())
                    app("]")
                }
                BracketExpr.BracketAccessor.LIST -> {
                    app(".get(")
                    if (it.argCastsInteger()) {
                        app("(Integer)")
                    }
                    app("", it.getArg().toCode())
                    app(")")
                }
                BracketExpr.BracketAccessor.MAP -> {
                    app(".get(", it.getArg().toCode())
                    app(")")
                }
            }
        }
        is CastExpr -> kcode("") {
            app("(", it.getCastType())
            app(") ", it.getCastExpr().toCode())
        }
        else -> kcode("//NOT IMPLEMENTED YET")
    }

}

fun Expr.isVariable() = this is IdentifierExpr && this.isDynamic()

fun Expr.conditionalFlagName(output : Boolean, suffix : String) = "${dirtyFlagName}_${output}$suffix"


val Expr.dirtyFlagSet by Delegates.lazy { expr : Expr ->
    FlagSet(expr.getInvalidFlags(), expr.getModel().getFlagBucketCount())
}

val Expr.invalidateFlagSet by Delegates.lazy { expr : Expr ->
    FlagSet(expr.getId())
}

val Expr.shouldReadFlagSet by Delegates.lazy { expr : Expr ->
    FlagSet(expr.getShouldReadFlags(), expr.getModel().getFlagBucketCount())
}

val Expr.conditionalFlags by Delegates.lazy { expr : Expr ->
    arrayListOf(FlagSet(expr.getRequirementFlagIndex(false)),
            FlagSet(expr.getRequirementFlagIndex(true)))
}

fun Expr.getRequirementFlagSet(expected : Boolean) : FlagSet = conditionalFlags[if(expected) 1 else 0]

fun FlagSet.notEmpty(cb : (suffix : String, value : Long) -> Unit) {
    buckets.withIndex().forEach {
        if (it.value != 0L) {
            cb(getWordSuffix(it.index), buckets[it.index])
        }
    }
}

fun FlagSet.getWordSuffix(wordIndex : Int) : String {
    return if(wordIndex == 0) "" else "_${wordIndex}"
}

fun FlagSet.localValue(bucketIndex : Int) =
        if (getLocalName() == null) binaryCode(bucketIndex)
        else "${getLocalName()}${getWordSuffix(bucketIndex)}"

fun FlagSet.binaryCode(bucketIndex : Int) = longToBinary(buckets[bucketIndex])


fun longToBinary(l : Long) =
        "0b${java.lang.Long.toBinaryString(l)}L"

fun <T> FlagSet.mapOr(other : FlagSet, cb : (suffix : String, index : Int) -> T) : List<T> {
    val min = Math.min(buckets.size(), other.buckets.size())
    val result = arrayListOf<T>()
    for (i in 0..(min - 1)) {
        // if these two can match by any chance, call the callback
        if (intersect(other, i)) {
            result.add(cb(getWordSuffix(i), i))
        }
    }
    return result
}

fun indexFromTag(tag : String) : kotlin.Int {
    val startIndex : kotlin.Int
    if (tag.startsWith("binding_")) {
        startIndex = "binding_".length();
    } else {
        startIndex = tag.lastIndexOf('_') + 1
    }
    return Integer.parseInt(tag.substring(startIndex))
}

class LayoutBinderWriter(val layoutBinder : LayoutBinder) {
    val model = layoutBinder.getModel()
    val indices = HashMap<BindingTarget, kotlin.Int>()
    val mDirtyFlags by Delegates.lazy {
        val fs = FlagSet(BitSet(), model.getFlagBucketCount());
        Arrays.fill(fs.buckets, -1)
        fs.setDynamic(true)
        model.localizeFlag(fs, "mDirtyFlags")
        fs
    }

    val dynamics by Delegates.lazy { model.getExprMap().values().filter { it.isDynamic() } }
    val className = layoutBinder.getImplementationName()

    val baseClassName = "${layoutBinder.getClassName()}"

    val includedBinders by Delegates.lazy {
        layoutBinder.getBindingTargets().filter { it.isBinder() }
    }

    val variables by Delegates.lazy {
        model.getExprMap().values().filterIsInstance(javaClass<IdentifierExpr>()).filter { it.isVariable() }
    }

    val usedVariables by Delegates.lazy {
        variables.filter {it.isUsed()}
    }

    public fun write(minSdk : kotlin.Int) : String  {
        layoutBinder.resolveWhichExpressionsAreUsed()
        calculateIndices();
        return kcode("package ${layoutBinder.getPackage()};") {
            nl("import ${layoutBinder.getModulePackage()}.R;")
            nl("import ${layoutBinder.getModulePackage()}.BR;")
            nl("import android.view.View;")
            val classDeclaration : String
            if (layoutBinder.hasVariations()) {
                classDeclaration = "${className} extends ${baseClassName}"
            } else {
                classDeclaration = "${className} extends android.databinding.ViewDataBinding"
            }
            nl("public class ${classDeclaration} {") {
                tab(declareIncludeViews())
                tab(declareViews())
                tab(declareVariables())
                tab(declareConstructor(minSdk))
                tab(declareInvalidateAll())
                tab(declareLog())
                tab(declareSetVariable())
                tab(variableSettersAndGetters())
                tab(onFieldChange())

                tab(executePendingBindings())

                tab(declareDirtyFlags())
                if (!layoutBinder.hasVariations()) {
                    tab(declareFactories())
                }
            }
            nl("}")
            tab(flagMapping())
            tab("//end")
        }.generate()
    }
    fun calculateIndices() : Unit {
        val taggedViews = layoutBinder.getBindingTargets().filter{
            it.isUsed() && it.getTag() != null && !it.isBinder()
        }
        taggedViews.forEach {
            indices.put(it, indexFromTag(it.getTag()))
        }
        val indexStart = maxIndex() + 1
        layoutBinder.getBindingTargets().filter{
            it.isUsed() && !taggedViews.contains(it)
        }.withIndex().forEach {
            indices.put(it.value, it.index + indexStart)
        }
    }
    fun declareIncludeViews() = kcode("") {
        nl("private static final android.databinding.ViewDataBinding.IncludedLayoutIndex[][] sIncludes;")
        nl("private static final android.util.SparseIntArray sViewsWithIds;")
        nl("static {") {
            val hasBinders = layoutBinder.getBindingTargets().firstOrNull{ it.isUsed() && it.isBinder()} != null
            if (!hasBinders) {
                tab("sIncludes = null;")
            } else {
                val numBindings = layoutBinder.getBindingTargets().filter{ it.isUsed() }.count()
                tab("sIncludes = new android.databinding.ViewDataBinding.IncludedLayoutIndex[${numBindings}][];")
                val includeMap = HashMap<BindingTarget, ArrayList<BindingTarget>>()
                layoutBinder.getBindingTargets().filter{ it.isUsed() && it.isBinder() }.forEach {
                    val includeTag = it.getTag();
                    val parent = layoutBinder.getBindingTargets().firstOrNull {
                        it.isUsed() && !it.isBinder() && includeTag.equals(it.getTag())
                    }
                    if (parent == null) {
                        throw IllegalStateException("Could not find parent of include file")
                    }
                    var list = includeMap.get(parent)
                    if (list == null) {
                        list = ArrayList<BindingTarget>()
                        includeMap.put(parent, list)
                    }
                    list.add(it)
                }

                includeMap.keySet().forEach {
                    val index = indices.get(it)
                    tab("sIncludes[${index}] = new android.databinding.ViewDataBinding.IncludedLayoutIndex[] {") {
                        includeMap.get(it).forEach {
                            val bindingIndex = indices.get(it)
                            val layoutName = it.getIncludedLayout()
                            tab("new android.databinding.ViewDataBinding.IncludedLayoutIndex(\"${layoutName}\", ${bindingIndex}, R.layout.${layoutName}),")
                        }
                    }
                    tab("};")
                }
            }
            val viewsWithIds = layoutBinder.getBindingTargets().filter {
                it.isUsed() && !it.isBinder() && (!it.supportsTag() || (it.getId() != null && it.getTag() == null))
            }
            if (viewsWithIds.isEmpty()) {
                tab("sViewsWithIds = null;")
            } else {
                tab("sViewsWithIds = new android.util.SparseIntArray();")
                viewsWithIds.forEach {
                    tab("sViewsWithIds.put(${it.androidId}, ${indices.get(it)});")
                }
            }
        }
        nl("}")
    }

    fun maxIndex() : kotlin.Int {
        val maxIndex = indices.values().max()
        if (maxIndex == null) {
            return -1
        } else {
            return maxIndex
        }
    }

    fun declareConstructor(minSdk : kotlin.Int) = kcode("") {
        val bindingCount = maxIndex() + 1
        val parameterType : String
        val superParam : String
        if (layoutBinder.isMerge()) {
            parameterType = "View[]"
            superParam = "root[0]"
        } else {
            parameterType = "View"
            superParam = "root"
        }
        val rootTagsSupported = minSdk >= 14
        if (layoutBinder.hasVariations()) {
            nl("")
            nl("public ${className}(${parameterType} root) {") {
                tab("this(${superParam}, mapBindings(root, ${bindingCount}, sIncludes, sViewsWithIds));")
            }
            nl("}")
            nl("private ${className}(${parameterType} root, Object[] bindings) {") {
                tab("super(${superParam}, ${model.getObservables().size()}") {
                    layoutBinder.getSortedTargets().filter { it.getId() != null }.forEach {
                        tab(", ${fieldConversion(it)}")
                    }
                    tab(");")
                }
            }
        } else {
            nl("public ${baseClassName}(${parameterType} root) {") {
                tab("super(${superParam}, ${model.getObservables().size()});")
                tab("final Object[] bindings = mapBindings(root, ${bindingCount}, sIncludes, sViewsWithIds);")
            }
        }
        tab("setRootTag(root);")
        val taggedViews = layoutBinder.getSortedTargets().filter{it.isUsed()}
        taggedViews.forEach {
            if (!layoutBinder.hasVariations() || it.getId() == null) {
                tab("this.${it.fieldName} = ${fieldConversion(it)};")
            }
            if (!it.isBinder()) {
                if (it.getResolvedType() != null && it.getResolvedType().extendsViewStub()) {
                    tab("this.${it.fieldName}.setContainingBinding(this);")
                }
                if (it.supportsTag() && it.getTag() != null &&
                        (rootTagsSupported || it.getTag().startsWith("binding_"))) {
                    val originalTag = it.getOriginalTag();
                    var tagValue = "null"
                    if (originalTag != null) {
                        tagValue = "\"${originalTag}\""
                        if (originalTag.startsWith("@")) {
                            var packageName = layoutBinder.getModulePackage()
                            if (originalTag.startsWith("@android:")) {
                                packageName = "android"
                            }
                            val slashIndex = originalTag.indexOf('/')
                            val resourceId = originalTag.substring(slashIndex + 1)
                            tagValue = "root.getResources().getString(${packageName}.R.string.${resourceId})"
                        }
                    }
                    tab("this.${it.fieldName}.setTag(${tagValue});")
                }
            }
        }
        tab("invalidateAll();");
        nl("}")
    }

    fun fieldConversion(target : BindingTarget) : String {
        if (!target.isUsed()) {
            return "null"
        } else {
            val index = indices.get(target)
            if (index == null) {
                throw IllegalStateException("Unknown binding target")
            }
            val variableName = "bindings[${index}]"
            return target.superConversion(variableName)
        }
    }

    fun declareInvalidateAll() = kcode("") {
        nl("@Override")
        nl("public void invalidateAll() {") {
            val fs = FlagSet(layoutBinder.getModel().getInvalidateAnyBitSet(),
                    layoutBinder.getModel().getFlagBucketCount());
            for (i in (0..(mDirtyFlags.buckets.size() - 1))) {
                tab("${mDirtyFlags.localValue(i)} = ${fs.localValue(i)};")
            }
            includedBinders.filter{it.isUsed()}.forEach { binder ->
                tab("${binder.fieldName}.invalidateAll();")
            }
        }
        nl("}")
    }

    fun declareSetVariable() = kcode("") {
        nl("public boolean setVariable(int variableId, Object variable) {") {
            tab("switch(variableId) {") {
                usedVariables.forEach {
                    tab ("case ${it.getName().br()} :") {
                        tab("${it.setterName}((${it.getResolvedType().toJavaCode()}) variable);")
                        tab("return true;")
                    }
                }
            }
            tab("}")
            tab("return false;")
        }
        nl("}")
    }

    fun declareLog() = kcode("") {
        nl("private void log(String msg, long i) {") {
            tab("""android.util.Log.d("BINDER", msg + ":" + Long.toHexString(i));""")
        }
        nl("}")
    }

    fun variableSettersAndGetters() = kcode("") {
        variables.filterNot{it.isUsed()}.forEach {
            nl("public void ${it.setterName}(${it.getResolvedType().toJavaCode()} ${it.readableName}) {") {
                tab("// not used, ignore")
            }
            nl("}")
            nl("")
            nl("public ${it.getResolvedType().toJavaCode()} ${it.getterName}() {") {
                tab("return ${it.getDefaultValue()};")
            }
            nl("}")
        }
        usedVariables.forEach {
            if (it.getUserDefinedType() != null) {
                nl("public void ${it.setterName}(${it.getResolvedType().toJavaCode()} ${it.readableName}) {") {
                    if (it.isObservable()) {
                        tab("updateRegistration(${it.getId()}, ${it.readableName});");
                    }
                    tab("this.${it.fieldName} = ${it.readableName};")
                    // set dirty flags!
                    val flagSet = it.invalidateFlagSet
                    mDirtyFlags.mapOr(flagSet) { suffix, index ->
                        tab("${mDirtyFlags.getLocalName()}$suffix |= ${flagSet.localValue(index)};")
                    }
                    tab("super.requestRebind();")
                }
                nl("}")
                nl("")
                nl("public ${it.getResolvedType().toJavaCode()} ${it.getterName}() {") {
                    tab("return ${it.fieldName};")
                }
                nl("}")
            }
        }
    }

    fun onFieldChange() = kcode("") {
        nl("@Override")
        nl("protected boolean onFieldChange(int localFieldId, Object object, int fieldId) {") {
            tab("switch (localFieldId) {") {
                model.getObservables().forEach {
                    tab("case ${it.getId()} :") {
                        tab("return ${it.onChangeName}((${it.getResolvedType().toJavaCode()}) object, fieldId);")
                    }
                }
            }
            tab("}")
            tab("return false;")
        }
        nl("}")
        nl("")

        model.getObservables().forEach {
            nl("private boolean ${it.onChangeName}(${it.getResolvedType().toJavaCode()} ${it.readableName}, int fieldId) {") {
                tab("switch (fieldId) {", {
                    val accessedFields: List<FieldAccessExpr> = it.getParents().filterIsInstance(javaClass<FieldAccessExpr>())
                    accessedFields.filter { it.canBeInvalidated() }
                            .groupBy { it.getName() }
                            .forEach {
                                tab("case ${it.key.br()}:") {
                                    val field = it.value.first()
                                    mDirtyFlags.mapOr(field.invalidateFlagSet) { suffix, index ->
                                        tab("${mDirtyFlags.localValue(index)} |= ${field.invalidateFlagSet.localValue(index)};")
                                    }
                                    tab("return true;")
                                }

                            }
                    tab("case ${"".br()}:") {
                        val flagSet = it.invalidateFlagSet
                        mDirtyFlags.mapOr(flagSet) { suffix, index ->
                            tab("${mDirtyFlags.getLocalName()}$suffix |= ${flagSet.localValue(index)};")
                        }
                        tab("return true;")
                    }

                })
                tab("}")
                tab("return false;")
            }
            nl("}")
            nl("")
        }
    }

    fun declareViews() = kcode("// views") {
        val oneLayout = !layoutBinder.hasVariations();
        layoutBinder.getSortedTargets().filter {it.isUsed() && (oneLayout || it.getId() == null)}.forEach {
            val access : String
            if (oneLayout && it.getId() != null) {
                access = "public"
            } else {
                access = "private"
            }
            nl("${access} final ${it.interfaceType} ${it.fieldName};")
        }
    }

    fun declareVariables() = kcode("// variables") {
        usedVariables.forEach {
            nl("private ${it.getResolvedType().toJavaCode()} ${it.fieldName};")
        }
    }

    fun declareDirtyFlags() = kcode("// dirty flag") {
        model.ext.localizedFlags.forEach { flag ->
            flag.notEmpty { suffix, value ->
                nl("private")
                app(" ", if(flag.isDynamic()) null else "static final");
                app(" ", " ${flag.type} ${flag.getLocalName()}$suffix = ${longToBinary(value)};")
            }
        }
    }

    fun flagMapping() = kcode("/* flag mapping") {
        if (model.getFlagMapping() != null) {
            val mapping = model.getFlagMapping()
            for (i in mapping.indices) {
                tab("flag $i: ${mapping[i]}")
            }
        }
        nl("flag mapping end*/")
    }

    fun executePendingBindings() = kcode("") {
        nl("@Override")
        nl("public void executePendingBindings() {") {
            val tmpDirtyFlags = FlagSet(mDirtyFlags.buckets)
            tmpDirtyFlags.setLocalName("dirtyFlags");
            for (i in (0..mDirtyFlags.buckets.size() - 1)) {
                tab("${tmpDirtyFlags.type} ${tmpDirtyFlags.localValue(i)} = ${mDirtyFlags.localValue(i)};")
                tab("${mDirtyFlags.localValue(i)} = 0;")
            }
            model.getPendingExpressions().filterNot {it.isVariable()}.forEach {
                tab("${it.getResolvedType().toJavaCode()} ${it.executePendingLocalName} = ${it.getDefaultValue()};")
            }
            Log.d {"writing executePendingBindings for $className"}
            do {
                val batch = ExprModel.filterShouldRead(model.getPendingExpressions()).toArrayList()
                Log.d {"batch: $batch"}
                val mJustRead = arrayListOf<Expr>()
                while (!batch.none()) {
                    val readNow = batch.filter { it.shouldReadNow(mJustRead) }
                    if (readNow.isEmpty()) {
                        throw IllegalStateException("do not know what I can read. bailing out ${batch.joinToString("\n")}")
                    }
                    Log.d { "new read now. batch size: ${batch.size()}, readNow size: ${readNow.size()}" }

                    readNow.forEach {
                        nl(readWithDependants(it, mJustRead, batch, tmpDirtyFlags))
                    }
                    batch.removeAll(mJustRead)
                }
                tab("// batch finished")
            } while(model.markBitsRead())

            //
            layoutBinder.getSortedTargets().filter { it.isUsed() }
                    .flatMap { it.getBindings() }
                    .groupBy { it.getExpr() }
                    .forEach {
                        val flagSet = it.key.dirtyFlagSet
                        tab("if (${tmpDirtyFlags.mapOr(flagSet){ suffix, index ->
                            "(${tmpDirtyFlags.localValue(index)} & ${flagSet.localValue(index)}) != 0"
                        }.joinToString(" || ")
                        }) {") {
                            it.value.forEach { binding ->
                                tab("// api target ${binding.getMinApi()}")
                                val fieldName : String
                                if (binding.getTarget().getViewClass().
                                        equals(binding.getTarget().getInterfaceType())) {
                                    fieldName = "this.${binding.getTarget().fieldName}"
                                } else {
                                    fieldName = "((${binding.getTarget().getViewClass()}) this.${binding.getTarget().fieldName})"
                                }
                                val bindingCode = binding.toJavaCode(fieldName, binding.getExpr().toCode().generate())
                                if (binding.getMinApi() > 1) {
                                    tab("if(getBuildSdkInt() >= ${binding.getMinApi()}) {") {
                                        tab("$bindingCode;")
                                    }
                                    tab("}")
                                } else {
                                    tab("$bindingCode;")
                                }
                            }
                        }
                        tab("}")
                    }
            includedBinders.filter{it.isUsed()}.forEach { binder ->
                tab("${binder.fieldName}.executePendingBindings();")
            }
            layoutBinder.getSortedTargets().filter{
                it.isUsed() && it.getResolvedType() != null && it.getResolvedType().extendsViewStub()
            }.forEach {
                tab("if (${it.fieldName}.getBinding() != null) {") {
                    tab("${it.fieldName}.getBinding().executePendingBindings();")
                }
                tab("}")
            }
        }
        nl("}")
    }

    fun readWithDependants(expr : Expr, mJustRead : MutableList<Expr>, batch : MutableList<Expr>,
            tmpDirtyFlags : FlagSet, inheritedFlags : FlagSet? = null) : KCode = kcode("") {
        mJustRead.add(expr)
        Log.d { "$className / readWithDependants: ${expr.getUniqueKey()}" }
        val flagSet = expr.shouldReadFlagSet
        val needsIfWrapper = inheritedFlags == null || !flagSet.bitsEqual(inheritedFlags)
        Log.d { "flag set:$flagSet . inherited flags: $inheritedFlags. need another if: $needsIfWrapper"}
        val ifClause = "if (${tmpDirtyFlags.mapOr(flagSet){ suffix, index ->
            "(${tmpDirtyFlags.localValue(index)} & ${flagSet.localValue(index)}) != 0"
        }.joinToString(" || ")
        })"

        val readCode = kcode("") {
            if (!expr.isVariable()) {
                // it is not a variable read it.
                tab("// read ${expr.getUniqueKey()}")
                // create an if case for all dependencies that might be null
                val nullables = expr.getDependencies().filter {
                    it.isMandatory() && it.getOther().getResolvedType().isNullable()
                }.map { it.getOther() }
                if (!expr.isEqualityCheck() && nullables.isNotEmpty()) {
                    tab ("if ( ${nullables.map { "${it.executePendingLocalName} != null" }.joinToString(" && ")}) {") {
                        tab("${expr.executePendingLocalName}").app(" = ", expr.toCode(true)).app(";")
                    }
                    tab("}")
                } else {
                    tab("${expr.executePendingLocalName}").app(" = ", expr.toCode(true)).app(";")
                }
                if (expr.isObservable()) {
                    tab("updateRegistration(${expr.getId()}, ${expr.executePendingLocalName});")
                }
            }

            // if I am the condition for an expression, set its flag
            val conditionals = expr.getDependants().filter { !it.isConditional()
                    && it.getDependant() is TernaryExpr && (it.getDependant() as TernaryExpr).getPred() == expr }
                    .map { it.getDependant() }
            if (conditionals.isNotEmpty()) {
                tab("// setting conditional flags")
                tab("if (${expr.executePendingLocalName}) {") {
                    conditionals.forEach {
                        val set = it.getRequirementFlagSet(true)
                        mDirtyFlags.mapOr(set) { suffix , index ->
                            tab("${tmpDirtyFlags.localValue(index)} |= ${set.localValue(index)};")
                        }
                    }
                }
                tab("} else {") {
                    conditionals.forEach {
                        val set = it.getRequirementFlagSet(false)
                        mDirtyFlags.mapOr(set) { suffix , index ->
                            tab("${tmpDirtyFlags.localValue(index)} |= ${set.localValue(index)};")
                        }
                    }
                } tab("}")
            }

            val chosen = expr.getDependants().filter {
                val dependant = it.getDependant()
                batch.contains(dependant) &&
                        dependant.shouldReadFlagSet.andNot(flagSet).isEmpty() &&
                        dependant.shouldReadNow(mJustRead)
            }
            if (chosen.isNotEmpty()) {
                val nextInheritedFlags = if (needsIfWrapper) flagSet else inheritedFlags
                chosen.forEach {
                    nl(readWithDependants(it.getDependant(), mJustRead, batch, tmpDirtyFlags, nextInheritedFlags))
                }
            }
        }
        if (needsIfWrapper) {
            tab(ifClause) {
                app(" {")
                nl(readCode)
            }
            tab("}")
        } else {
            nl(readCode)
        }
    }

    fun declareFactories() = kcode("") {
        if (!layoutBinder.isMerge()) {
            nl("public static ${baseClassName} inflate(android.view.ViewGroup root) {") {
                tab("return bind(android.view.LayoutInflater.from(root.getContext()).inflate(${layoutBinder.getModulePackage()}.R.layout.${layoutBinder.getLayoutname()}, root, true));")
            }
            nl("}")
            nl("public static ${baseClassName} inflate(android.content.Context context) {") {
                tab("return bind(android.view.LayoutInflater.from(context).inflate(${layoutBinder.getModulePackage()}.R.layout.${layoutBinder.getLayoutname()}, null, false));")
            }
            nl("}")
            nl("public static ${baseClassName} bind(android.view.View view) {") {
                tab("if (!\"${layoutBinder.getTag()}_0\".equals(view.getTag())) {") {
                    tab("throw new RuntimeException(\"view tag isn't correct on view\");")
                }
                tab("}")
                tab("return new ${baseClassName}(view);")
            }
            nl("}")
        }
    }

    public fun writeBaseClass() : String =
        kcode("package ${layoutBinder.getPackage()};") {
            nl("import android.databinding.Bindable;")
            nl("import android.databinding.DataBindingUtil;")
            nl("import android.databinding.ViewDataBinding;")
            nl("public abstract class ${baseClassName} extends ViewDataBinding {")
            layoutBinder.getSortedTargets().filter{it.getId() != null}.forEach {
                tab("public final ${it.interfaceType} ${it.fieldName};")
            }
            nl("")
            tab("protected ${baseClassName}(android.view.View root_, int localFieldCount") {
                layoutBinder.getSortedTargets().filter{it.getId() != null}.forEach {
                    tab(", ${it.interfaceType} ${it.constructorParamName}")
                }
            }
            tab(") {") {
                tab("super(root_, localFieldCount);")
                layoutBinder.getSortedTargets().filter{it.getId() != null}.forEach {
                    tab("this.${it.fieldName} = ${it.constructorParamName};")
                }
            }
            tab("}")
            nl("")
            variables.forEach {
                if (it.getUserDefinedType() != null) {
                    //it.getExpandedUserDefinedType(ModelAnalyzer.getInstance());
                    val type = ModelAnalyzer.getInstance().applyImports(it.getUserDefinedType(), model.getImports())
                    tab("public abstract void ${it.setterName}(${type} ${it.readableName});")
                }
            }
            tab("public static ${baseClassName} inflate(android.view.ViewGroup root) {") {
                tab("return DataBindingUtil.<${baseClassName}>inflate(root.getContext(), ${layoutBinder.getModulePackage()}.R.layout.${layoutBinder.getLayoutname()}, root, true);")
            }
            tab("}")
            tab("public static ${baseClassName} inflate(android.content.Context context) {") {
                tab("return DataBindingUtil.<${baseClassName}>inflate(context, ${layoutBinder.getModulePackage()}.R.layout.${layoutBinder.getLayoutname()}, null, false);")
            }
            tab("}")
            tab("public static ${baseClassName} bind(android.view.View view) {") {
                tab("return (${baseClassName})DataBindingUtil.bindTo(view, ${layoutBinder.getModulePackage()}.R.layout.${layoutBinder.getLayoutname()});")
            }
            tab("}")
            nl("}")
        }.generate()
}