// Copyright 2021 Google Inc. All rights reserved.
//
// 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 java

import (
	"fmt"

	"android/soong/android"

	"github.com/google/blueprint"
	"github.com/google/blueprint/proptools"
)

// Contains code that is common to both platform_bootclasspath and bootclasspath_fragment.

// addDependencyOntoApexVariants adds dependencies onto the appropriate apex specific variants of
// the module as specified in the ApexVariantReference list.
func addDependencyOntoApexVariants(ctx android.BottomUpMutatorContext, propertyName string, refs []ApexVariantReference, tagType bootclasspathDependencyTagType) {
	for i, ref := range refs {
		apex := proptools.StringDefault(ref.Apex, "platform")

		if ref.Module == nil {
			ctx.PropertyErrorf(propertyName, "missing module name at position %d", i)
			continue
		}
		name := proptools.String(ref.Module)

		addDependencyOntoApexModulePair(ctx, apex, name, tagType)
	}
}

// addDependencyOntoApexModulePair adds a dependency onto the specified APEX specific variant or the
// specified module.
//
// If apex="platform" or "system_ext" then this adds a dependency onto the platform variant of the
// module. This adds dependencies onto the prebuilt and source modules with the specified name,
// depending on which ones are available. Visiting must use isActiveModule to select the preferred
// module when both source and prebuilt modules are available.
//
// Use gatherApexModulePairDepsWithTag to retrieve the dependencies.
func addDependencyOntoApexModulePair(ctx android.BottomUpMutatorContext, apex string, name string, tagType bootclasspathDependencyTagType) {
	tag := bootclasspathDependencyTag{
		typ: tagType,
	}
	target := ctx.Module().Target()
	if android.IsConfiguredJarForPlatform(apex) {
		// Platform variant, add a direct dependency.
		ctx.AddFarVariationDependencies(target.Variations(), tag, name)
	} else {
		// A module in an apex.  Dependencies can't be added directly onto an apex variation, as that would
		// require constructing a full ApexInfo configuration, which can't be predicted here.  Add a dependency
		// on the apex instead, and annotate the dependency tag with the desired module in the apex.
		tag.moduleInApex = name
		ctx.AddFarVariationDependencies(target.Variations(), tag, apex)
	}

}

// gatherFragments collects fragments that are direct dependencies of this module, as well as
// any fragments in apexes via the dependency on the apex.  It returns a list of the fragment
// modules and map from apex name to the fragment in that apex.
func gatherFragments(ctx android.BaseModuleContext) ([]android.Module, map[string]android.Module) {
	var fragments []android.Module

	type fragmentInApex struct {
		module string
		apex   string
	}

	var fragmentsInApexes []fragmentInApex

	// Find any direct dependencies, as well as a list of the modules in apexes.
	ctx.VisitDirectDeps(func(module android.Module) {
		t := ctx.OtherModuleDependencyTag(module)
		if bcpTag, ok := t.(bootclasspathDependencyTag); ok && bcpTag.typ == fragment {
			if bcpTag.moduleInApex != "" {
				fragmentsInApexes = append(fragmentsInApexes, fragmentInApex{bcpTag.moduleInApex, ctx.OtherModuleName(module)})
			} else {
				fragments = append(fragments, module)
			}
		}
	})

	fragmentsMap := make(map[string]android.Module)
	for _, fragmentInApex := range fragmentsInApexes {
		var found android.Module
		// Find a desired module in an apex.
		ctx.WalkDeps(func(child, parent android.Module) bool {
			t := ctx.OtherModuleDependencyTag(child)
			if parent == ctx.Module() {
				if bcpTag, ok := t.(bootclasspathDependencyTag); ok && bcpTag.typ == fragment && ctx.OtherModuleName(child) == fragmentInApex.apex {
					// This is the dependency from this module to the apex, recurse into it.
					return true
				}
			} else if android.IsDontReplaceSourceWithPrebuiltTag(t) {
				return false
			} else if t == android.PrebuiltDepTag {
				return false
			} else if IsBootclasspathFragmentContentDepTag(t) {
				return false
			} else if android.RemoveOptionalPrebuiltPrefix(ctx.OtherModuleName(child)) == fragmentInApex.module {
				// This is the desired module inside the apex.
				if found != nil && child != found {
					panic(fmt.Errorf("found two conflicting modules %q in apex %q: %s and %s",
						fragmentInApex.module, fragmentInApex.apex, found, child))
				}
				found = child
			}
			return false
		})
		if found != nil {
			if existing, exists := fragmentsMap[fragmentInApex.apex]; exists {
				ctx.ModuleErrorf("apex %s has multiple fragments, %s and %s", fragmentInApex.apex, fragmentInApex.module, existing)
			} else {
				fragmentsMap[fragmentInApex.apex] = found
				fragments = append(fragments, found)
			}
		} else if !ctx.Config().AllowMissingDependencies() {
			ctx.ModuleErrorf("failed to find fragment %q in apex %q\n",
				fragmentInApex.module, fragmentInApex.apex)
		}
	}
	return fragments, fragmentsMap
}

// gatherApexModulePairDepsWithTag returns the list of dependencies with the supplied tag that was
// added by addDependencyOntoApexModulePair.
func gatherApexModulePairDepsWithTag(ctx android.BaseModuleContext, tagType bootclasspathDependencyTagType) ([]android.Module, map[android.Module]string) {
	var modules []android.Module
	modulesToApex := make(map[android.Module]string)

	type moduleInApex struct {
		module string
		apex   string
	}

	var modulesInApexes []moduleInApex

	ctx.VisitDirectDeps(func(module android.Module) {
		t := ctx.OtherModuleDependencyTag(module)
		if bcpTag, ok := t.(bootclasspathDependencyTag); ok && bcpTag.typ == tagType {
			if bcpTag.moduleInApex != "" {
				modulesInApexes = append(modulesInApexes, moduleInApex{bcpTag.moduleInApex, ctx.OtherModuleName(module)})
			} else {
				modules = append(modules, module)
			}
		}
	})

	for _, moduleInApex := range modulesInApexes {
		var found android.Module
		ctx.WalkDeps(func(child, parent android.Module) bool {
			t := ctx.OtherModuleDependencyTag(child)
			if parent == ctx.Module() {
				if bcpTag, ok := t.(bootclasspathDependencyTag); ok && bcpTag.typ == tagType && ctx.OtherModuleName(child) == moduleInApex.apex {
					// recurse into the apex
					return true
				}
			} else if tagType != fragment && android.IsFragmentInApexTag(t) {
				return true
			} else if android.IsDontReplaceSourceWithPrebuiltTag(t) {
				return false
			} else if t == android.PrebuiltDepTag {
				return false
			} else if IsBootclasspathFragmentContentDepTag(t) {
				return false
			} else if android.RemoveOptionalPrebuiltPrefix(ctx.OtherModuleName(child)) == moduleInApex.module {
				if found != nil && child != found {
					panic(fmt.Errorf("found two conflicting modules %q in apex %q: %s and %s",
						moduleInApex.module, moduleInApex.apex, found, child))
				}
				found = child
			}
			return false
		})
		if found != nil {
			modules = append(modules, found)
			if existing, exists := modulesToApex[found]; exists && existing != moduleInApex.apex {
				ctx.ModuleErrorf("module %s is in two apexes, %s and %s", moduleInApex.module, existing, moduleInApex.apex)
			} else {
				modulesToApex[found] = moduleInApex.apex
			}
		} else if !ctx.Config().AllowMissingDependencies() {
			ctx.ModuleErrorf("failed to find module %q in apex %q\n",
				moduleInApex.module, moduleInApex.apex)
		}
	}
	return modules, modulesToApex
}

// ApexVariantReference specifies a particular apex variant of a module.
type ApexVariantReference struct {
	android.BpPrintableBase

	// The name of the module apex variant, i.e. the apex containing the module variant.
	//
	// If this is not specified then it defaults to "platform" which will cause a dependency to be
	// added to the module's platform variant.
	//
	// A value of system_ext should be used for any module that will be part of the system_ext
	// partition.
	Apex *string

	// The name of the module.
	Module *string
}

// BootclasspathFragmentsDepsProperties contains properties related to dependencies onto fragments.
type BootclasspathFragmentsDepsProperties struct {
	// The names of the bootclasspath_fragment modules that form part of this module.
	Fragments []ApexVariantReference
}

// addDependenciesOntoFragments adds dependencies to the fragments specified in this properties
// structure.
func (p *BootclasspathFragmentsDepsProperties) addDependenciesOntoFragments(ctx android.BottomUpMutatorContext) {
	addDependencyOntoApexVariants(ctx, "fragments", p.Fragments, fragment)
}

// bootclasspathDependencyTag defines dependencies from/to bootclasspath_fragment,
// prebuilt_bootclasspath_fragment and platform_bootclasspath onto either source or prebuilt
// modules.
type bootclasspathDependencyTag struct {
	blueprint.BaseDependencyTag

	typ bootclasspathDependencyTagType

	// moduleInApex is set to the name of the desired module when this dependency points
	// to the apex that the modules is contained in.
	moduleInApex string
}

type bootclasspathDependencyTagType int

const (
	// The tag used for dependencies onto bootclasspath_fragments.
	fragment bootclasspathDependencyTagType = iota
	// The tag used for dependencies onto platform_bootclasspath.
	platform
	dexpreoptBootJar
	artBootJar
	platformBootJar
	apexBootJar
)

func (t bootclasspathDependencyTag) ExcludeFromVisibilityEnforcement() {
}

func (t bootclasspathDependencyTag) LicenseAnnotations() []android.LicenseAnnotation {
	return []android.LicenseAnnotation{android.LicenseAnnotationSharedDependency}
}

// Dependencies that use the bootclasspathDependencyTag instances are only added after all the
// visibility checking has been done so this has no functional effect. However, it does make it
// clear that visibility is not being enforced on these tags.
var _ android.ExcludeFromVisibilityEnforcementTag = bootclasspathDependencyTag{}

// BootclasspathNestedAPIProperties defines properties related to the API provided by parts of the
// bootclasspath that are nested within the main BootclasspathAPIProperties.
type BootclasspathNestedAPIProperties struct {
	// java_library or preferably, java_sdk_library modules providing stub classes that define the
	// APIs provided by this bootclasspath_fragment.
	Stub_libs proptools.Configurable[[]string]
}

// BootclasspathAPIProperties defines properties for defining the API provided by parts of the
// bootclasspath.
type BootclasspathAPIProperties struct {
	// Api properties provide information about the APIs provided by the bootclasspath_fragment.
	// Properties in this section apply to public, system and test api scopes. They DO NOT apply to
	// core_platform as that is a special, ART specific scope, that does not follow the pattern and so
	// has its own section. It is in the process of being deprecated and replaced by the system scope
	// but this will remain for the foreseeable future to maintain backwards compatibility.
	//
	// Every bootclasspath_fragment must specify at least one stubs_lib in this section and must
	// specify stubs for all the APIs provided by its contents. Failure to do so will lead to those
	// methods being inaccessible to other parts of Android, including but not limited to
	// applications.
	Api BootclasspathNestedAPIProperties

	// Properties related to the core platform API surface.
	//
	// This must only be used by the following modules:
	// * ART
	// * Conscrypt
	// * I18N
	//
	// The bootclasspath_fragments for each of the above modules must specify at least one stubs_lib
	// and must specify stubs for all the APIs provided by its contents. Failure to do so will lead to
	// those methods being inaccessible to the other modules in the list.
	Core_platform_api BootclasspathNestedAPIProperties
}

// apiScopeToStubLibs calculates the stub library modules for each relevant *HiddenAPIScope from the
// Stub_libs properties.
func (p BootclasspathAPIProperties) apiScopeToStubLibs(ctx android.BaseModuleContext) map[*HiddenAPIScope][]string {
	m := map[*HiddenAPIScope][]string{}
	for _, apiScope := range hiddenAPISdkLibrarySupportedScopes {
		m[apiScope] = p.Api.Stub_libs.GetOrDefault(ctx, nil)
	}
	m[CorePlatformHiddenAPIScope] = p.Core_platform_api.Stub_libs.GetOrDefault(ctx, nil)
	return m
}