package internal

import (
	"os"
	"path/filepath"

	. "github.com/onsi/ginkgo/v2"
	. "github.com/onsi/gomega"
)

var _ = Describe("Parser", func() {
	var tmpDir string

	BeforeEach(func() {
		var err error
		tmpDir, err = os.MkdirTemp("", "ndpgen-test-*")
		Expect(err).NotTo(HaveOccurred())
	})

	AfterEach(func() {
		os.RemoveAll(tmpDir)
	})

	Describe("ParseDirectory", func() {
		It("should parse a simple host service interface", func() {
			src := `package host

import "context"

// SubsonicAPIService provides access to Navidrome's Subsonic API.
//nd:hostservice name=SubsonicAPI permission=subsonicapi
type SubsonicAPIService interface {
	// Call executes a Subsonic API request.
	//nd:hostfunc
	Call(ctx context.Context, uri string) (response string, err error)
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "service.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			services, err := ParseDirectory(tmpDir)
			Expect(err).NotTo(HaveOccurred())
			Expect(services).To(HaveLen(1))

			svc := services[0]
			Expect(svc.Name).To(Equal("SubsonicAPI"))
			Expect(svc.Permission).To(Equal("subsonicapi"))
			Expect(svc.Interface).To(Equal("SubsonicAPIService"))
			Expect(svc.Methods).To(HaveLen(1))

			m := svc.Methods[0]
			Expect(m.Name).To(Equal("Call"))
			Expect(m.HasError).To(BeTrue())
			Expect(m.Params).To(HaveLen(1))
			Expect(m.Params[0].Name).To(Equal("uri"))
			Expect(m.Params[0].Type).To(Equal("string"))
			Expect(m.Returns).To(HaveLen(1))
			Expect(m.Returns[0].Name).To(Equal("response"))
			Expect(m.Returns[0].Type).To(Equal("string"))
		})

		It("should parse multiple methods", func() {
			src := `package host

import "context"

// SchedulerService provides scheduling capabilities.
//nd:hostservice name=Scheduler permission=scheduler
type SchedulerService interface {
	//nd:hostfunc
	ScheduleRecurring(ctx context.Context, cronExpression string) (scheduleID string, err error)

	//nd:hostfunc
	ScheduleOneTime(ctx context.Context, delaySeconds int32) (scheduleID string, err error)

	//nd:hostfunc
	CancelSchedule(ctx context.Context, scheduleID string) (canceled bool, err error)
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "scheduler.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			services, err := ParseDirectory(tmpDir)
			Expect(err).NotTo(HaveOccurred())
			Expect(services).To(HaveLen(1))

			svc := services[0]
			Expect(svc.Name).To(Equal("Scheduler"))
			Expect(svc.Methods).To(HaveLen(3))

			Expect(svc.Methods[0].Name).To(Equal("ScheduleRecurring"))
			Expect(svc.Methods[0].Params[0].Type).To(Equal("string"))

			Expect(svc.Methods[1].Name).To(Equal("ScheduleOneTime"))
			Expect(svc.Methods[1].Params[0].Type).To(Equal("int32"))

			Expect(svc.Methods[2].Name).To(Equal("CancelSchedule"))
			Expect(svc.Methods[2].Returns[0].Type).To(Equal("bool"))
		})

		It("should skip methods without hostfunc annotation", func() {
			src := `package host

import "context"

//nd:hostservice name=Test permission=test
type TestService interface {
	//nd:hostfunc
	Exported(ctx context.Context) error

	// This method is not exported
	NotExported(ctx context.Context) error
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "test.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			services, err := ParseDirectory(tmpDir)
			Expect(err).NotTo(HaveOccurred())
			Expect(services).To(HaveLen(1))
			Expect(services[0].Methods).To(HaveLen(1))
			Expect(services[0].Methods[0].Name).To(Equal("Exported"))
		})

		It("should parse raw=true annotation", func() {
			src := `package host

import "context"

//nd:hostservice name=Stream permission=stream
type StreamService interface {
	//nd:hostfunc raw=true
	GetStream(ctx context.Context, uri string) (contentType string, data []byte, err error)
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "stream.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			services, err := ParseDirectory(tmpDir)
			Expect(err).NotTo(HaveOccurred())
			Expect(services).To(HaveLen(1))

			m := services[0].Methods[0]
			Expect(m.Name).To(Equal("GetStream"))
			Expect(m.Raw).To(BeTrue())
			Expect(m.HasError).To(BeTrue())
			Expect(m.Returns).To(HaveLen(2))
			Expect(m.Returns[0].Name).To(Equal("contentType"))
			Expect(m.Returns[0].Type).To(Equal("string"))
			Expect(m.Returns[1].Name).To(Equal("data"))
			Expect(m.Returns[1].Type).To(Equal("[]byte"))
		})

		It("should set Raw=false when raw annotation is absent", func() {
			src := `package host

import "context"

//nd:hostservice name=Test permission=test
type TestService interface {
	//nd:hostfunc
	Call(ctx context.Context, uri string) (response string, err error)
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "test.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			services, err := ParseDirectory(tmpDir)
			Expect(err).NotTo(HaveOccurred())
			Expect(services[0].Methods[0].Raw).To(BeFalse())
		})

		It("should reject raw=true with invalid return signature", func() {
			src := `package host

import "context"

//nd:hostservice name=Test permission=test
type TestService interface {
	//nd:hostfunc raw=true
	BadRaw(ctx context.Context, uri string) (result string, err error)
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "test.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			_, err = ParseDirectory(tmpDir)
			Expect(err).To(HaveOccurred())
			Expect(err.Error()).To(ContainSubstring("raw=true"))
			Expect(err.Error()).To(ContainSubstring("must return (string, []byte, error)"))
		})

		It("should reject raw=true without error return", func() {
			src := `package host

import "context"

//nd:hostservice name=Test permission=test
type TestService interface {
	//nd:hostfunc raw=true
	BadRaw(ctx context.Context, uri string) (contentType string, data []byte)
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "test.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			_, err = ParseDirectory(tmpDir)
			Expect(err).To(HaveOccurred())
			Expect(err.Error()).To(ContainSubstring("raw=true"))
		})

		It("should parse mixed raw and non-raw methods", func() {
			src := `package host

import "context"

//nd:hostservice name=API permission=api
type APIService interface {
	//nd:hostfunc
	Call(ctx context.Context, uri string) (responseJSON string, err error)

	//nd:hostfunc raw=true
	CallRaw(ctx context.Context, uri string) (contentType string, data []byte, err error)
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "api.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			services, err := ParseDirectory(tmpDir)
			Expect(err).NotTo(HaveOccurred())
			Expect(services).To(HaveLen(1))
			Expect(services[0].Methods).To(HaveLen(2))
			Expect(services[0].Methods[0].Raw).To(BeFalse())
			Expect(services[0].Methods[1].Raw).To(BeTrue())
			Expect(services[0].HasRawMethods()).To(BeTrue())
		})

		It("should handle custom export name", func() {
			src := `package host

import "context"

//nd:hostservice name=Test permission=test
type TestService interface {
	//nd:hostfunc name=custom_export_name
	MyMethod(ctx context.Context) error
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "test.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			services, err := ParseDirectory(tmpDir)
			Expect(err).NotTo(HaveOccurred())
			Expect(services[0].Methods[0].ExportName).To(Equal("custom_export_name"))
			Expect(services[0].Methods[0].FunctionName("test")).To(Equal("custom_export_name"))
		})

		It("should skip generated files", func() {
			regularSrc := `package host

import "context"

//nd:hostservice name=Test permission=test
type TestService interface {
	//nd:hostfunc
	Method(ctx context.Context) error
}
`
			genSrc := `// Code generated. DO NOT EDIT.
package host

//nd:hostservice name=Generated permission=gen
type GeneratedService interface {
	//nd:hostfunc
	Method() error
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "test.go"), []byte(regularSrc), 0600)
			Expect(err).NotTo(HaveOccurred())
			err = os.WriteFile(filepath.Join(tmpDir, "test_gen.go"), []byte(genSrc), 0600)
			Expect(err).NotTo(HaveOccurred())

			services, err := ParseDirectory(tmpDir)
			Expect(err).NotTo(HaveOccurred())
			Expect(services).To(HaveLen(1))
			Expect(services[0].Name).To(Equal("Test"))
		})

		It("should skip interfaces without hostservice annotation", func() {
			src := `package host

import "context"

// Regular interface without annotation
type RegularInterface interface {
	Method(ctx context.Context) error
}

//nd:hostservice name=Annotated permission=annotated
type AnnotatedService interface {
	//nd:hostfunc
	Method(ctx context.Context) error
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "test.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			services, err := ParseDirectory(tmpDir)
			Expect(err).NotTo(HaveOccurred())
			Expect(services).To(HaveLen(1))
			Expect(services[0].Name).To(Equal("Annotated"))
		})

		It("should return empty slice for directory with no host services", func() {
			src := `package host

type RegularInterface interface {
	Method() error
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "test.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			services, err := ParseDirectory(tmpDir)
			Expect(err).NotTo(HaveOccurred())
			Expect(services).To(BeEmpty())
		})
	})

	Describe("parseKeyValuePairs", func() {
		It("should parse key=value pairs", func() {
			result := parseKeyValuePairs("name=Test permission=test")
			Expect(result).To(HaveKeyWithValue("name", "Test"))
			Expect(result).To(HaveKeyWithValue("permission", "test"))
		})

		It("should return nil for empty input", func() {
			result := parseKeyValuePairs("")
			Expect(result).To(BeNil())
		})
	})

	Describe("typeToString", func() {
		It("should handle basic types", func() {
			src := `package test
type T interface {
	Method(s string, i int, b bool) ([]byte, error)
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "types.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			// Parse and verify type conversion works
			// This is implicitly tested through ParseDirectory
		})

		It("should convert interface{} to any", func() {
			src := `package test

import "context"

//nd:hostservice name=Test permission=test
type TestService interface {
	//nd:hostfunc
	GetMetadata(ctx context.Context) (data map[string]interface{}, err error)
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "test.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			services, err := ParseDirectory(tmpDir)
			Expect(err).NotTo(HaveOccurred())
			Expect(services).To(HaveLen(1))
			Expect(services[0].Methods[0].Returns[0].Type).To(Equal("map[string]any"))
		})
	})

	Describe("Method helpers", func() {
		It("should generate correct function names", func() {
			m := Method{Name: "Call"}
			Expect(m.FunctionName("subsonicapi")).To(Equal("subsonicapi_call"))

			m.ExportName = "custom_name"
			Expect(m.FunctionName("subsonicapi")).To(Equal("custom_name"))
		})

		It("should generate correct type names", func() {
			m := Method{Name: "Call"}
			// Host-side types are public
			Expect(m.RequestTypeName("SubsonicAPI")).To(Equal("SubsonicAPICallRequest"))
			Expect(m.ResponseTypeName("SubsonicAPI")).To(Equal("SubsonicAPICallResponse"))
			// Client/PDK types are private
			Expect(m.ClientRequestTypeName("SubsonicAPI")).To(Equal("subsonicAPICallRequest"))
			Expect(m.ClientResponseTypeName("SubsonicAPI")).To(Equal("subsonicAPICallResponse"))
		})
	})

	Describe("Service helpers", func() {
		It("should generate correct output file name", func() {
			s := Service{Name: "SubsonicAPI"}
			Expect(s.OutputFileName()).To(Equal("subsonicapi_gen.go"))
		})

		It("should generate correct export prefix", func() {
			s := Service{Name: "SubsonicAPI"}
			Expect(s.ExportPrefix()).To(Equal("subsonicapi"))
		})
	})

	Describe("ParseCapabilities", func() {
		It("should parse a simple capability interface", func() {
			src := `package capabilities

// MetadataAgent provides metadata retrieval.
//nd:capability name=metadata
type MetadataAgent interface {
	// GetArtistBiography returns artist biography.
	//nd:export name=nd_get_artist_biography
	GetArtistBiography(ArtistInput) (ArtistBiographyOutput, error)
}

// ArtistInput is the input for artist-related functions.
type ArtistInput struct {
	// ID is the artist ID.
	ID string ` + "`json:\"id\"`" + `
	// Name is the artist name.
	Name string ` + "`json:\"name\"`" + `
}

// ArtistBiographyOutput is the output for GetArtistBiography.
type ArtistBiographyOutput struct {
	// Biography is the biography text.
	Biography string ` + "`json:\"biography\"`" + `
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "metadata.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			capabilities, err := ParseCapabilities(tmpDir)
			Expect(err).NotTo(HaveOccurred())
			Expect(capabilities).To(HaveLen(1))

			cap := capabilities[0]
			Expect(cap.Name).To(Equal("metadata"))
			Expect(cap.Interface).To(Equal("MetadataAgent"))
			Expect(cap.Required).To(BeFalse())
			Expect(cap.Doc).To(ContainSubstring("MetadataAgent provides metadata retrieval"))
			Expect(cap.Methods).To(HaveLen(1))

			m := cap.Methods[0]
			Expect(m.Name).To(Equal("GetArtistBiography"))
			Expect(m.ExportName).To(Equal("nd_get_artist_biography"))
			Expect(m.Input.Type).To(Equal("ArtistInput"))
			Expect(m.Output.Type).To(Equal("ArtistBiographyOutput"))

			// Check structs were collected
			Expect(cap.Structs).To(HaveLen(2))
		})

		It("should parse a required capability", func() {
			src := `package capabilities

// Scrobbler requires all methods to be implemented.
//nd:capability name=scrobbler required=true
type Scrobbler interface {
	//nd:export name=nd_scrobbler_is_authorized
	IsAuthorized(AuthInput) (AuthOutput, error)

	//nd:export name=nd_scrobbler_scrobble
	Scrobble(ScrobbleInput) (ScrobblerOutput, error)
}

type AuthInput struct {
	UserID string ` + "`json:\"userId\"`" + `
}

type AuthOutput struct {
	Authorized bool ` + "`json:\"authorized\"`" + `
}

type ScrobbleInput struct {
	UserID string ` + "`json:\"userId\"`" + `
}

type ScrobblerOutput struct {
	Error *string ` + "`json:\"error,omitempty\"`" + `
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "scrobbler.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			capabilities, err := ParseCapabilities(tmpDir)
			Expect(err).NotTo(HaveOccurred())
			Expect(capabilities).To(HaveLen(1))

			cap := capabilities[0]
			Expect(cap.Name).To(Equal("scrobbler"))
			Expect(cap.Required).To(BeTrue())
			Expect(cap.Methods).To(HaveLen(2))
		})

		It("should parse type aliases and consts", func() {
			src := `package capabilities

//nd:capability name=scrobbler required=true
type Scrobbler interface {
	//nd:export name=nd_scrobble
	Scrobble(ScrobbleInput) (ScrobblerOutput, error)
}

type ScrobbleInput struct {
	UserID string ` + "`json:\"userId\"`" + `
}

// ScrobblerErrorType indicates error handling behavior.
type ScrobblerErrorType string

const (
	// ScrobblerErrorNone indicates no error.
	ScrobblerErrorNone ScrobblerErrorType = "none"
	// ScrobblerErrorRetry indicates retry later.
	ScrobblerErrorRetry ScrobblerErrorType = "retry"
)

type ScrobblerOutput struct {
	ErrorType *ScrobblerErrorType ` + "`json:\"errorType,omitempty\"`" + `
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "scrobbler.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			capabilities, err := ParseCapabilities(tmpDir)
			Expect(err).NotTo(HaveOccurred())
			Expect(capabilities).To(HaveLen(1))

			cap := capabilities[0]
			// Type alias should be collected
			Expect(cap.TypeAliases).To(HaveLen(1))
			Expect(cap.TypeAliases[0].Name).To(Equal("ScrobblerErrorType"))
			Expect(cap.TypeAliases[0].Type).To(Equal("string"))

			// Consts should be collected
			Expect(cap.Consts).To(HaveLen(1))
			Expect(cap.Consts[0].Type).To(Equal("ScrobblerErrorType"))
			Expect(cap.Consts[0].Values).To(HaveLen(2))
			Expect(cap.Consts[0].Values[0].Name).To(Equal("ScrobblerErrorNone"))
			Expect(cap.Consts[0].Values[0].Value).To(Equal(`"none"`))
		})

		It("should collect nested struct dependencies", func() {
			src := `package capabilities

//nd:capability name=metadata
type MetadataAgent interface {
	//nd:export name=nd_get_images
	GetImages(ArtistInput) (ImagesOutput, error)
}

type ArtistInput struct {
	ID string ` + "`json:\"id\"`" + `
}

type ImagesOutput struct {
	Images []ImageInfo ` + "`json:\"images\"`" + `
}

type ImageInfo struct {
	URL string ` + "`json:\"url\"`" + `
	Size int32 ` + "`json:\"size\"`" + `
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "metadata.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			capabilities, err := ParseCapabilities(tmpDir)
			Expect(err).NotTo(HaveOccurred())
			Expect(capabilities).To(HaveLen(1))

			cap := capabilities[0]
			// Should collect all 3 structs: ArtistInput, ImagesOutput, and ImageInfo
			Expect(cap.Structs).To(HaveLen(3))

			structNames := make([]string, len(cap.Structs))
			for i, s := range cap.Structs {
				structNames[i] = s.Name
			}
			Expect(structNames).To(ContainElements("ArtistInput", "ImagesOutput", "ImageInfo"))
		})

		It("should return empty slice for directory with no capabilities", func() {
			src := `package capabilities

type RegularInterface interface {
	Method() error
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "test.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			capabilities, err := ParseCapabilities(tmpDir)
			Expect(err).NotTo(HaveOccurred())
			Expect(capabilities).To(BeEmpty())
		})

		It("should ignore methods without export annotation", func() {
			src := `package capabilities

//nd:capability name=test
type TestCapability interface {
	//nd:export name=nd_exported
	ExportedMethod(Input) (Output, error)

	// This method has no export annotation
	NotExportedMethod(Input) (Output, error)
}

type Input struct {
	Value string ` + "`json:\"value\"`" + `
}

type Output struct {
	Result string ` + "`json:\"result\"`" + `
}
`
			err := os.WriteFile(filepath.Join(tmpDir, "test.go"), []byte(src), 0600)
			Expect(err).NotTo(HaveOccurred())

			capabilities, err := ParseCapabilities(tmpDir)
			Expect(err).NotTo(HaveOccurred())
			Expect(capabilities).To(HaveLen(1))

			// Only the exported method should be captured
			Expect(capabilities[0].Methods).To(HaveLen(1))
			Expect(capabilities[0].Methods[0].Name).To(Equal("ExportedMethod"))
		})
	})

	Describe("Export helpers", func() {
		It("should generate correct provider interface name", func() {
			e := Export{Name: "GetArtistBiography"}
			Expect(e.ProviderInterfaceName()).To(Equal("ArtistBiographyProvider"))

			e = Export{Name: "OnInit"}
			Expect(e.ProviderInterfaceName()).To(Equal("InitProvider"))
		})

		It("should generate correct impl variable name", func() {
			e := Export{Name: "GetArtistBiography"}
			Expect(e.ImplVarName()).To(Equal("artistBiographyImpl"))

			e = Export{Name: "OnInit"}
			Expect(e.ImplVarName()).To(Equal("initImpl"))
		})

		It("should generate correct export function name", func() {
			e := Export{Name: "GetArtistBiography", ExportName: "nd_get_artist_biography"}
			Expect(e.ExportFuncName()).To(Equal("_NdGetArtistBiography"))
		})
	})
})