omissis/go-jsonschema

package generator

import (
    "errors"
    "fmt"
    "go/format"
    "os"
    "strings"

    "github.com/atombender/go-jsonschema/internal/x/text"
    "github.com/atombender/go-jsonschema/pkg/codegen"
    "github.com/atombender/go-jsonschema/pkg/schemas"
)

const (
    varNamePlainStruct = "plain"
    varNameRawMap      = "raw"
    interfaceTypeName  = "interface{}"
)

var (
    errSchemaHasNoRoot                = errors.New("schema has no root")
    errArrayPropertyItems             = errors.New("array property must have 'items' set to a type")
    errEnumArrCannotBeEmpty           = errors.New("enum array cannot be empty")
    errEnumNonPrimitiveVal            = errors.New("enum has non-primitive value")
    errMapURIToPackageName            = errors.New("unable to map schema URI to Go package name")
    errExpectedNamedType              = errors.New("expected named type")
    errConflictSameFile               = errors.New("conflict: same file")
    errDefinitionDoesNotExistInSchema = errors.New("definition does not exist in schema")
    errCannotGenerateReferencedType   = errors.New("cannot generate referenced type")
)

type Generator struct {
    caser      *text.Caser
    config     Config
    inScope    map[qualifiedDefinition]struct{}
    outputs    map[string]*output
    warner     func(string)
    formatters []formatter
    loader     schemas.Loader
}

type qualifiedDefinition struct {
    schema *schemas.Schema
    name   string
}

func New(config Config) (*Generator, error) {
    formatters := []formatter{
        &jsonFormatter{},
    }
    if config.ExtraImports {
        formatters = append(formatters, &yamlFormatter{})
    }

    generator := &Generator{
        caser:      text.NewCaser(config.Capitalizations, config.ResolveExtensions),
        config:     config,
        inScope:    map[qualifiedDefinition]struct{}{},
        outputs:    map[string]*output{},
        warner:     config.Warner,
        formatters: formatters,
        loader:     config.Loader,
    }

    if config.Loader == nil {
        generator.loader = schemas.NewDefaultCacheLoader(config.ResolveExtensions, config.YAMLExtensions)
    }

    return generator, nil
}

func (g *Generator) Sources() map[string][]byte {
    var maxLineLength int32 = 80

    sources := make(map[string]*strings.Builder, len(g.outputs))

    for _, output := range g.outputs {
        if output.file.FileName == "" {
            continue
        }

        emitter := codegen.NewEmitter(maxLineLength)
        output.file.Generate(emitter)

        sb, ok := sources[output.file.FileName]
        if !ok {
            sb = &strings.Builder{}
            sources[output.file.FileName] = sb
        }

        _, _ = sb.WriteString(emitter.String())
    }

    result := make(map[string][]byte, len(sources))

    for f, sb := range sources {
        source := []byte(sb.String())

        src, err := format.Source(source)
        if err != nil {
            g.config.Warner(fmt.Sprintf("The generated code could not be formatted automatically; "+
                "falling back to unformatted: %s", err))

            src = source
        }

        result[f] = src
    }

    return result
}

func (g *Generator) DoFile(fileName string) error {
    var err error

    var schema *schemas.Schema

    if fileName == "-" {
        schema, err = schemas.FromJSONReader(os.Stdin)
        if err != nil {
            return fmt.Errorf("error parsing from standard input: %w", err)
        }
    } else {
        schema, err = g.loader.Load(fileName, "")
        if err != nil {
            return fmt.Errorf("error parsing from file %s: %w", fileName, err)
        }
    }

    return g.addFile(fileName, schema)
}

func (g *Generator) addFile(fileName string, schema *schemas.Schema) error {
    o, err := g.findOutputFileForSchemaID(schema.ID)
    if err != nil {
        return err
    }

    return (&schemaGenerator{
        Generator:      g,
        schema:         schema,
        schemaFileName: fileName,
        output:         o,
    }).generateRootType()
}

func (g *Generator) getRootTypeName(schema *schemas.Schema, fileName string) string {
    for _, m := range g.config.SchemaMappings {
        if m.SchemaID == schema.ID && m.RootType != "" {
            return m.RootType
        }
    }

    if g.config.StructNameFromTitle && schema.Title != "" {
        return g.caser.Identifierize(schema.Title)
    }

    return g.caser.IdentifierFromFileName(fileName)
}

func (g *Generator) findOutputFileForSchemaID(id string) (*output, error) {
    if o, ok := g.outputs[id]; ok {
        return o, nil
    }

    for _, m := range g.config.SchemaMappings {
        if m.SchemaID == id {
            return g.beginOutput(id, m.OutputName, m.PackageName)
        }
    }

    return g.beginOutput(id, g.config.DefaultOutputName, g.config.DefaultPackageName)
}

func (g *Generator) beginOutput(
    id string,
    outputName, packageName string,
) (*output, error) {
    if packageName == "" {
        return nil, fmt.Errorf("%w: %q", errMapURIToPackageName, id)
    }

    for _, o := range g.outputs {
        if o.file.FileName == outputName && o.file.Package.QualifiedName != packageName {
            return nil, fmt.Errorf(
                "%w (%s) mapped to two different Go packages (%q and %q) for schema %q",
                errConflictSameFile, o.file.FileName, o.file.Package.QualifiedName, packageName, id)
        }

        if o.file.FileName == outputName && o.file.Package.QualifiedName == packageName {
            return o, nil
        }
    }

    pkg := codegen.Package{
        QualifiedName: packageName,
    }

    output := &output{
        warner: g.warner,
        file: &codegen.File{
            FileName: outputName,
            Package:  pkg,
        },
        declsBySchema: map[*schemas.Type]*codegen.TypeDecl{},
        declsByName:   map[string]*codegen.TypeDecl{},
    }
    g.outputs[id] = output

    return output, nil
}

func (g *Generator) makeEnumConstantName(typeName, value string) string {
    if strings.ContainsAny(typeName[len(typeName)-1:], "0123456789") {
        return typeName + "_" + g.caser.Identifierize(value)
    }

    return typeName + g.caser.Identifierize(value)
}