package settings

import (
	"bufio"
	"context"
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"sort"
	"strings"
	"sync"
)

type RuntimeUpdater func(context.Context, map[string]string) error
type Option struct {
	Label string `json:"label"`
	Value string `json:"value"`
}
type Field struct {
	Key          string   `json:"key"`
	Label        string   `json:"label"`
	Description  string   `json:"description,omitempty"`
	Secret       bool     `json:"secret,omitempty"`
	Type         string   `json:"type,omitempty"`
	Options      []Option `json:"options,omitempty"`
	Value        string   `json:"value"`
	Configured   bool     `json:"configured"`
	DefaultValue string   `json:"-"`
}
type Group struct {
	ID          string  `json:"id"`
	Title       string  `json:"title"`
	Description string  `json:"description"`
	Fields      []Field `json:"fields"`
}
type Capability struct {
	ID          string `json:"id"`
	Label       string `json:"label"`
	ReqKey      string `json:"reqKey"`
	Engine      string `json:"engine,omitempty"`
	EngineLabel string `json:"engineLabel,omitempty"`
	Enabled     bool   `json:"enabled"`
}
type EngineAssignment struct {
	ID              string `json:"id"`
	Label           string `json:"label"`
	Engine          string `json:"engine"`
	EngineLabel     string `json:"engineLabel"`
	Connected       bool   `json:"connected"`
	ConnectionLabel string `json:"connectionLabel"`
	ReqKey          string `json:"reqKey"`
	Configurable    bool   `json:"configurable"`
	Field           *Field `json:"field,omitempty"`
}
type Services struct {
	Visual       bool `json:"visual"`
	Evolink      bool `json:"evolink"`
	Seedance     bool `json:"seedance"`
	Bailian      bool `json:"bailian"`
	Auth         bool `json:"auth"`
	Organization bool `json:"organization"`
}
type Payload struct {
	Services          Services           `json:"services"`
	Capabilities      []Capability       `json:"capabilities"`
	EngineAssignments []EngineAssignment `json:"engineAssignments"`
	Groups            []Group            `json:"groups"`
	RestartRequired   bool               `json:"restartRequired,omitempty"`
}
type Service struct {
	mu          sync.Mutex
	path        string
	environment map[string]string
	update      RuntimeUpdater
	billing     BillingAccountWriter
}

type BillingAccount struct {
	AccountName, BankName, AccountNumber, Contact string
}

type BillingAccountWriter interface {
	SaveBillingAccount(context.Context, BillingAccount) error
}

func New(path string, environment map[string]string, updater RuntimeUpdater) *Service {
	return &Service{path: path, environment: cloneStrings(environment), update: updater}
}

// LoadEnvironment reads only the settings whitelist. Values already supplied
// by the process win, matching Next's process.env-over-file precedence.
func LoadEnvironment(path string, environment map[string]string) (map[string]string, error) {
	file, err := readEnv(path)
	if err != nil {
		return nil, err
	}
	merged := cloneStrings(environment)
	for key, value := range file {
		if _, allowed := fieldIndex[key]; !allowed {
			continue
		}
		if _, exists := merged[key]; !exists {
			merged[key] = value
		}
	}
	return merged, nil
}

func RuntimeSettingKeys() []string {
	keys := make([]string, 0, len(fieldIndex))
	for key := range fieldIndex {
		keys = append(keys, key)
	}
	sort.Strings(keys)
	return keys
}

func (s *Service) WithBillingAccountWriter(writer BillingAccountWriter) *Service {
	s.billing = writer
	return s
}
func (s *Service) Get(ctx context.Context) (any, error) {
	if err := ctx.Err(); err != nil {
		return nil, err
	}
	s.mu.Lock()
	defer s.mu.Unlock()
	return s.get()
}
func (s *Service) Save(ctx context.Context, values map[string]any) (any, error) {
	if err := ctx.Err(); err != nil {
		return nil, err
	}
	s.mu.Lock()
	defer s.mu.Unlock()
	updates := map[string]string{}
	for key, raw := range values {
		field, ok := fieldIndex[key]
		next, stringValue := raw.(string)
		if !ok || !stringValue {
			continue
		}
		next = strings.TrimSpace(next)
		if field.Secret && next == "" {
			continue
		}
		updates[key] = next
	}
	if len(updates) > 0 {
		// Capture the complete persisted view before writing so a partial billing
		// account update cannot blank sibling fields that only exist in the file.
		persisted, err := readEnv(s.path)
		if err != nil {
			return nil, err
		}
		if err := s.write(updates); err != nil {
			return nil, err
		}
		if s.update != nil {
			if err := s.update(ctx, cloneStrings(updates)); err != nil {
				return nil, fmt.Errorf("apply runtime settings: %w", err)
			}
		}
		for key, value := range updates {
			s.environment[key] = value
			persisted[key] = value
		}
		if s.billing != nil && containsBillingAccountUpdate(updates) {
			if err := s.billing.SaveBillingAccount(ctx, BillingAccount{
				AccountName:   billingSetting(s.environment, persisted, "ZHINIAN_BILLING_ACCOUNT_NAME"),
				BankName:      billingSetting(s.environment, persisted, "ZHINIAN_BILLING_ACCOUNT_BANK"),
				AccountNumber: billingSetting(s.environment, persisted, "ZHINIAN_BILLING_ACCOUNT_NUMBER"),
				Contact:       billingSetting(s.environment, persisted, "ZHINIAN_BILLING_CONTACT"),
			}); err != nil {
				return nil, fmt.Errorf("apply billing account settings: %w", err)
			}
		}
	}
	payload, err := s.get()
	if err == nil && requiresRestart(updates) {
		payload.RestartRequired = true
	}
	return payload, err
}

func billingSetting(environment, persisted map[string]string, key string) string {
	if value, ok := environment[key]; ok {
		return value
	}
	return persisted[key]
}

func containsBillingAccountUpdate(updates map[string]string) bool {
	for key := range updates {
		switch key {
		case "ZHINIAN_BILLING_ACCOUNT_NAME", "ZHINIAN_BILLING_ACCOUNT_BANK", "ZHINIAN_BILLING_ACCOUNT_NUMBER", "ZHINIAN_BILLING_CONTACT":
			return true
		}
	}
	return false
}

func requiresRestart(updates map[string]string) bool {
	for key := range updates {
		switch key {
		case "ZHINIAN_BILLING_ACCOUNT_NAME", "ZHINIAN_BILLING_ACCOUNT_BANK", "ZHINIAN_BILLING_ACCOUNT_NUMBER", "ZHINIAN_BILLING_CONTACT":
			continue
		default:
			return true
		}
	}
	return false
}
func (s *Service) get() (Payload, error) {
	file, err := readEnv(s.path)
	if err != nil {
		return Payload{}, err
	}
	current := func(field Field) string {
		if value, ok := s.environment[field.Key]; ok {
			return value
		}
		if value, ok := file[field.Key]; ok {
			return value
		}
		return field.DefaultValue
	}
	groups := definitions()
	for gi := range groups {
		for fi := range groups[gi].Fields {
			field := &groups[gi].Fields[fi]
			raw := current(*field)
			field.Configured = raw != ""
			if !field.Secret {
				field.Value = raw
			}
		}
	}
	image := normalizeImage(current(fieldIndex["IMAGE_GENERATE_ENGINE"]))
	video := normalizeVideo(current(fieldIndex["VIDEO_GENERATE_ENGINE"]))
	imageModel := map[string]string{"jimeng": lookup(s.environment, file, "JIMENG_IMAGE_GENERATE_46_REQ_KEY", "jimeng_seedream46_cvtob"), "evolink": lookup(s.environment, file, "EVOLINK_IMAGE_MODEL", "gpt-image-2"), "bailian": lookup(s.environment, file, "BAILIAN_IMAGE_MODEL", "wan2.7-image-pro")}[image]
	videoModel := lookup(s.environment, file, "SEEDANCE_MODEL", "doubao-seedance-2-0-260128")
	if video == "bailian" {
		videoModel = lookup(s.environment, file, "BAILIAN_VIDEO_MODEL", "wan2.7-i2v-2026-04-25")
	}
	imageConnected := connected(image, s.environment, file)
	videoConnected := connected(video, s.environment, file)
	imageField := project(fieldIndex["IMAGE_GENERATE_ENGINE"], image, s.environment, file)
	videoField := project(fieldIndex["VIDEO_GENERATE_ENGINE"], video, s.environment, file)
	assignments := []EngineAssignment{{ID: "image.generate", Label: "图片生成", Engine: image, EngineLabel: label(image), Connected: imageConnected, ConnectionLabel: connection(imageConnected), ReqKey: imageModel, Configurable: true, Field: &imageField}, {ID: "video.generate", Label: "视频生成", Engine: video, EngineLabel: label(video), Connected: videoConnected, ConnectionLabel: connection(videoConnected), ReqKey: videoModel, Configurable: true, Field: &videoField}}
	services := Services{Visual: connected("jimeng", s.environment, file), Evolink: connected("evolink", s.environment, file), Seedance: connected("seedance", s.environment, file), Bailian: connected("bailian", s.environment, file), Auth: lookup(s.environment, file, "ZHINIAN_AUTH_SESSION_SECRET", "") != "", Organization: lookup(s.environment, file, "DATABASE_URL", "") != "" || lookup(s.environment, file, "ZHINIAN_AUTH_SESSION_SECRET", "") != ""}
	return Payload{Services: services, Capabilities: []Capability{{ID: "image.generate", Label: "图片生成 4.6", ReqKey: imageModel, Engine: image, EngineLabel: label(image), Enabled: true}, {ID: "video.generate", Label: "视频生成", ReqKey: videoModel, Engine: video, EngineLabel: label(video), Enabled: true}}, EngineAssignments: assignments, Groups: groups}, nil
}
func (s *Service) write(updates map[string]string) error {
	data, err := os.ReadFile(s.path)
	if err != nil && !errors.Is(err, os.ErrNotExist) {
		return fmt.Errorf("read settings file: %w", err)
	}
	if errors.Is(err, os.ErrNotExist) {
		data = []byte("# 智念AIGC平台 API 配置\n")
	}
	lines := strings.Split(strings.ReplaceAll(string(data), "\r\n", "\n"), "\n")
	seen := map[string]bool{}
	for index, line := range lines {
		key, _, ok := splitLine(line)
		if !ok {
			continue
		}
		if value, replace := updates[key]; replace {
			lines[index] = key + "=" + formatValue(value)
			seen[key] = true
		}
	}
	missing := []string{}
	for key := range updates {
		if !seen[key] {
			missing = append(missing, key)
		}
	}
	sort.Strings(missing)
	if len(missing) > 0 {
		for len(lines) > 0 && lines[len(lines)-1] == "" {
			lines = lines[:len(lines)-1]
		}
		if len(lines) > 0 {
			lines = append(lines, "")
		}
		lines = append(lines, "# Managed by 智念AIGC平台 设置页")
		for _, key := range missing {
			lines = append(lines, key+"="+formatValue(updates[key]))
		}
	}
	if err := os.MkdirAll(filepath.Dir(s.path), 0o755); err != nil {
		return err
	}
	temp, err := os.CreateTemp(filepath.Dir(s.path), ".settings-*.tmp")
	if err != nil {
		return err
	}
	name := temp.Name()
	defer os.Remove(name)
	if err = temp.Chmod(0o600); err == nil {
		_, err = temp.WriteString(strings.TrimRight(strings.Join(lines, "\n"), "\n") + "\n")
	}
	if err == nil {
		err = temp.Sync()
	}
	closeErr := temp.Close()
	if err == nil {
		err = closeErr
	}
	if err != nil {
		return err
	}
	return os.Rename(name, s.path)
}
func readEnv(path string) (map[string]string, error) {
	file, err := os.Open(path)
	if errors.Is(err, os.ErrNotExist) {
		return map[string]string{}, nil
	}
	if err != nil {
		return nil, err
	}
	defer file.Close()
	result := map[string]string{}
	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		key, raw, ok := splitLine(scanner.Text())
		if ok {
			result[key] = parseValue(raw)
		}
	}
	return result, scanner.Err()
}
func splitLine(line string) (string, string, bool) {
	index := strings.IndexByte(line, '=')
	if index < 1 {
		return "", "", false
	}
	key := strings.TrimSpace(line[:index])
	if !validKey(key) {
		return "", "", false
	}
	return key, strings.TrimSpace(line[index+1:]), true
}
func validKey(key string) bool {
	for index, r := range key {
		if !(r == '_' || r >= 'A' && r <= 'Z' || r >= 'a' && r <= 'z' || index > 0 && r >= '0' && r <= '9') {
			return false
		}
	}
	return key != ""
}
func parseValue(raw string) string {
	raw = strings.TrimSpace(raw)
	if len(raw) >= 2 && ((raw[0] == '"' && raw[len(raw)-1] == '"') || (raw[0] == '\'' && raw[len(raw)-1] == '\'')) {
		if raw[0] == '\'' {
			return raw[1 : len(raw)-1]
		}
		var out strings.Builder
		escaped := false
		for _, r := range raw[1 : len(raw)-1] {
			if escaped {
				switch r {
				case 'n':
					out.WriteByte('\n')
				case '"', '\\':
					out.WriteRune(r)
				default:
					out.WriteByte('\\')
					out.WriteRune(r)
				}
				escaped = false
			} else if r == '\\' {
				escaped = true
			} else {
				out.WriteRune(r)
			}
		}
		return out.String()
	}
	if i := strings.Index(raw, " #"); i >= 0 {
		raw = raw[:i]
	}
	return strings.TrimSpace(raw)
}
func formatValue(value string) string {
	if value == "" {
		return ""
	}
	if !strings.ContainsAny(value, " \t\r\n#\"'\\") {
		return value
	}
	return "\"" + strings.NewReplacer("\\", "\\\\", "\"", "\\\"", "\n", "\\n", "\r", "\\r").Replace(value) + "\""
}
func cloneStrings(input map[string]string) map[string]string {
	out := map[string]string{}
	for key, value := range input {
		out[key] = value
	}
	return out
}
func lookup(environment, file map[string]string, key, fallback string) string {
	if value, ok := environment[key]; ok {
		return value
	}
	if value, ok := file[key]; ok {
		return value
	}
	return fallback
}
func project(field Field, value string, environment, file map[string]string) Field {
	field.Value = value
	field.Configured = lookup(environment, file, field.Key, "") != ""
	return field
}
func normalizeImage(value string) string {
	value = strings.ToLower(strings.TrimSpace(value))
	if value == "evolink" || value == "bailian" {
		return value
	}
	return "jimeng"
}
func normalizeVideo(value string) string {
	if strings.ToLower(strings.TrimSpace(value)) == "bailian" {
		return "bailian"
	}
	return "seedance"
}
func label(engine string) string {
	switch engine {
	case "evolink":
		return "EvoLink"
	case "bailian":
		return "阿里云百炼"
	case "seedance":
		return "Seedance"
	default:
		return "即梦"
	}
}
func connection(ok bool) string {
	if ok {
		return "已连接"
	}
	return "待配置"
}
func connected(engine string, environment, file map[string]string) bool {
	switch engine {
	case "evolink":
		return mock(lookup(environment, file, "EVOLINK_MOCK", "auto"), lookup(environment, file, "EVOLINK_API_KEY", "") != "")
	case "seedance":
		return mock(lookup(environment, file, "SEEDANCE_MOCK", "auto"), lookup(environment, file, "SEEDANCE_API_KEY", "") != "")
	case "bailian":
		flag := strings.ToLower(strings.TrimSpace(lookup(environment, file, "BAILIAN_MOCK", "auto")))
		return flag != "1" && flag != "true" && lookup(environment, file, "BAILIAN_API_KEY", "") != ""
	default:
		return mock(lookup(environment, file, "JIMENG_VISUAL_MOCK", "auto"), lookup(environment, file, "VOLCENGINE_ACCESS_KEY_ID", "") != "" && lookup(environment, file, "VOLCENGINE_SECRET_ACCESS_KEY", "") != "")
	}
}
func mock(flag string, configured bool) bool {
	flag = strings.ToLower(strings.TrimSpace(flag))
	if flag == "1" || flag == "true" {
		return false
	}
	if flag == "0" || flag == "false" {
		return true
	}
	return configured
}

func definitions() []Group {
	return []Group{
		{ID: "auth", Title: "平台账号安全", Description: "平台自建手机号账号登录。", Fields: []Field{{Key: "ZHINIAN_AUTH_REQUIRED", Label: "登录保护", Type: "select", DefaultValue: "auto", Options: []Option{{Label: "自动", Value: "auto"}, {Label: "启用", Value: "1"}, {Label: "停用", Value: "0"}}}, {Key: "ZHINIAN_AUTH_SESSION_SECRET", Label: "会话签名密钥", Secret: true, Type: "password"}}},
		{ID: "billing", Title: "企业计费", Description: "企业计费和对公账户信息。", Fields: []Field{{Key: "ZHINIAN_BILLING_REQUIRED", Label: "真实任务计费", Type: "select", DefaultValue: "1", Options: []Option{{Label: "启用", Value: "1"}, {Label: "停用（免计费）", Value: "0"}}}, {Key: "ZHINIAN_BILLING_ACCOUNT_NAME", Label: "对公账户名称"}, {Key: "ZHINIAN_BILLING_ACCOUNT_BANK", Label: "开户行"}, {Key: "ZHINIAN_BILLING_ACCOUNT_NUMBER", Label: "银行账号"}, {Key: "ZHINIAN_BILLING_CONTACT", Label: "充值对接信息"}}},
		{ID: "visual", Title: "即梦图片 API", Description: "火山 AK/SK。", Fields: []Field{{Key: "VOLCENGINE_ACCESS_KEY_ID", Label: "Access Key ID", Secret: true, Type: "password"}, {Key: "VOLCENGINE_SECRET_ACCESS_KEY", Label: "Secret Access Key", Secret: true, Type: "password"}}},
		{ID: "evolink", Title: "EvoLink 图片 API", Description: "GPT Image 2 图片生成。", Fields: []Field{{Key: "EVOLINK_API_KEY", Label: "EvoLink API Key", Secret: true, Type: "password"}, {Key: "EVOLINK_BASE_URL", Label: "Base URL", DefaultValue: "https://api.evolink.ai"}, {Key: "EVOLINK_IMAGE_MODEL", Label: "图片模型", DefaultValue: "gpt-image-2"}, {Key: "EVOLINK_IMAGE_QUALITY", Label: "质量", DefaultValue: "medium"}}},
		{ID: "seedance", Title: "Seedance 视频 API", Description: "火山方舟 API Key。", Fields: []Field{{Key: "SEEDANCE_API_KEY", Label: "方舟 API Key", Secret: true, Type: "password"}}},
		{ID: "bailian", Title: "阿里云百炼 API", Description: "万相图片与视频。", Fields: []Field{{Key: "BAILIAN_API_KEY", Label: "百炼 API Key", Secret: true, Type: "password"}, {Key: "BAILIAN_BASE_URL", Label: "Base URL", DefaultValue: "https://llm-126wneubbdo6dbr5.cn-beijing.maas.aliyuncs.com/compatible-mode/v1"}, {Key: "BAILIAN_IMAGE_MODEL", Label: "图片模型", DefaultValue: "wan2.7-image-pro"}, {Key: "BAILIAN_VIDEO_MODEL", Label: "视频模型", DefaultValue: "wan2.7-i2v-2026-04-25"}}},
		{ID: "oss", Title: "OSS 资产存储", Description: "共享资产存储。", Fields: []Field{{Key: "ALI_OSS_ENDPOINT", Label: "Endpoint"}, {Key: "ALI_OSS_BUCKET", Label: "Bucket"}, {Key: "ALI_OSS_ACCESS_KEY_ID", Label: "Access Key ID", Secret: true, Type: "password"}, {Key: "ALI_OSS_ACCESS_KEY_SECRET", Label: "Access Key Secret", Secret: true, Type: "password"}, {Key: "ALI_OSS_PUBLIC_BASE_URL", Label: "公开访问 Base URL"}}},
	}
}

var fieldIndex = func() map[string]Field {
	result := map[string]Field{}
	for _, group := range definitions() {
		for _, field := range group.Fields {
			result[field.Key] = field
		}
	}
	result["IMAGE_GENERATE_ENGINE"] = Field{Key: "IMAGE_GENERATE_ENGINE", Label: "图片生成", Type: "select", DefaultValue: "jimeng", Options: []Option{{Label: "即梦 / 火山视觉", Value: "jimeng"}, {Label: "EvoLink GPT Image 2", Value: "evolink"}, {Label: "阿里云百炼 Wan 2.7", Value: "bailian"}}}
	result["VIDEO_GENERATE_ENGINE"] = Field{Key: "VIDEO_GENERATE_ENGINE", Label: "视频生成", Type: "select", DefaultValue: "bailian", Options: []Option{{Label: "Seedance", Value: "seedance"}, {Label: "阿里云百炼 Wan 2.7", Value: "bailian"}}}
	return result
}()