package methods

import (
	"context"
	"encoding/json"
	"log/slog"
	"slices"

	"github.com/titanous/json5"

	"github.com/nextlevelbuilder/goclaw/internal/bus"
	"github.com/nextlevelbuilder/goclaw/internal/config"
	"github.com/nextlevelbuilder/goclaw/internal/gateway"
	"github.com/nextlevelbuilder/goclaw/internal/i18n"
	"github.com/nextlevelbuilder/goclaw/internal/store"
	"github.com/nextlevelbuilder/goclaw/internal/systemmessages"
	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
)

// ConfigMethods handles config.get, config.apply, config.patch, config.schema.
// Matching TS src/gateway/server-methods/config.ts.
type ConfigMethods struct {
	cfg          *config.Config
	cfgPath      string
	secretsStore store.ConfigSecretsStore
	syncFn       func(ctx context.Context, cfg *config.Config) // nil-safe; syncs non-secret settings to system_configs
	eventBus     bus.EventPublisher                            // nil-safe; broadcasts config change events
}

func NewConfigMethods(cfg *config.Config, cfgPath string, secretsStore store.ConfigSecretsStore, eventBus bus.EventPublisher) *ConfigMethods {
	return &ConfigMethods{cfg: cfg, cfgPath: cfgPath, secretsStore: secretsStore, eventBus: eventBus}
}

// SetSystemConfigSync sets a callback to sync config to system_configs after save.
// The callback receives the final resolved config (with secrets + env applied).
func (m *ConfigMethods) SetSystemConfigSync(fn func(ctx context.Context, cfg *config.Config)) {
	m.syncFn = fn
}

func (m *ConfigMethods) Register(router *gateway.MethodRouter) {
	router.Register(protocol.MethodConfigGet, m.requireMasterScope(m.requireOwner(m.handleGet)))
	router.Register(protocol.MethodConfigApply, m.requireMasterScope(m.requireOwner(m.handleApply)))
	router.Register(protocol.MethodConfigPatch, m.requireMasterScope(m.requireOwner(m.handlePatch)))
	router.Register(protocol.MethodConfigSchema, m.requireMasterScope(m.requireOwner(m.handleSchema)))
	// config.defaults is read-only + secret-free (Go consts + agents.defaults overlay),
	// so it only needs requireMasterScope — owner gating would spam auth errors for
	// operators viewing agent detail pages.
	router.Register(protocol.MethodConfigDefaults, m.requireMasterScope(m.handleDefaults))
}

// requireOwner wraps a handler to only allow owner-role users.
func (m *ConfigMethods) requireOwner(next gateway.MethodHandler) gateway.MethodHandler {
	return func(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
		if !client.IsOwner() {
			locale := store.LocaleFromContext(ctx)
			client.SendResponse(protocol.NewErrorResponse(
				req.ID, protocol.ErrUnauthorized,
				i18n.T(locale, i18n.MsgPermissionDenied, req.Method),
			))
			return
		}
		next(ctx, client, req)
	}
}

// requireMasterScope rejects config.* calls when the caller's ctx is scoped to
// a non-master tenant. System owner callers (bypass-all) are allowed through.
//
// Background: config.* mutates the master in-memory *config.Config and the
// on-disk config.json. A non-master tenant admin calling config.patch would
// corrupt master state + leak master config to other tenants. This guard keeps
// config.* strictly master-scoped until a tenant-aware refactor lands.
//
// Shares the predicate with store.IsMasterScope so HTTP and WS layers can't
// drift — same rule, one source of truth.
func (m *ConfigMethods) requireMasterScope(next gateway.MethodHandler) gateway.MethodHandler {
	return func(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
		if !store.IsMasterScope(ctx) {
			locale := store.LocaleFromContext(ctx)
			client.SendResponse(protocol.NewErrorResponse(
				req.ID,
				protocol.ErrUnauthorized,
				i18n.T(locale, i18n.MsgConfigMasterScopeOnly),
			))
			return
		}
		next(ctx, client, req)
	}
}

func (m *ConfigMethods) handleGet(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
	client.SendResponse(protocol.NewOKResponse(req.ID, map[string]any{
		"config": m.cfg.MaskedCopy(),
		"hash":   m.cfg.Hash(),
		"path":   m.cfgPath,
	}))
}

// handleApply replaces the entire config with the provided JSON5 raw content.
// Matching TS config.apply (src/gateway/server-methods/config.ts:435-486).
func (m *ConfigMethods) handleApply(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
	locale := store.LocaleFromContext(ctx)
	var params struct {
		Raw      string `json:"raw"`
		BaseHash string `json:"baseHash"`
	}
	if req.Params != nil {
		json.Unmarshal(req.Params, &params)
	}

	if params.Raw == "" {
		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRawConfigRequired)))
		return
	}

	// Optimistic concurrency: validate hash if provided
	if params.BaseHash != "" && params.BaseHash != m.cfg.Hash() {
		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgConfigHashMismatch)))
		return
	}

	// Parse the new config
	newCfg := config.Default()
	if err := json5.Unmarshal([]byte(params.Raw), newCfg); err != nil {
		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidRequest, err.Error())))
		return
	}

	// Extract secrets → save to config_secrets table, strip all from file
	m.saveSecretsToStore(ctx, newCfg)
	newCfg.StripSecrets()

	// Save to disk
	if err := config.Save(m.cfgPath, newCfg); err != nil {
		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToSave, "config", err.Error())))
		return
	}

	// Update in-memory config and restore secrets
	m.cfg.ReplaceFrom(newCfg)
	if m.secretsStore != nil {
		if secrets, err := m.secretsStore.GetAll(ctx); err == nil {
			m.cfg.ApplyDBSecrets(secrets)
		}
	}
	m.cfg.ApplyEnvOverrides()
	m.syncToSystemConfigs(ctx)
	m.broadcastChanged()
	emitAudit(m.eventBus, client, "config.applied", "config", "gateway")

	client.SendResponse(protocol.NewOKResponse(req.ID, map[string]any{
		"ok":      true,
		"path":    m.cfgPath,
		"config":  m.cfg.MaskedCopy(),
		"hash":    m.cfg.Hash(),
		"restart": false,
	}))
}

// handlePatch merges a partial config update into the current config.
// Matching TS config.patch (src/gateway/server-methods/config.ts:321-434).
func (m *ConfigMethods) handlePatch(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
	locale := store.LocaleFromContext(ctx)
	var params struct {
		Raw      string `json:"raw"`
		BaseHash string `json:"baseHash"`
	}
	if req.Params != nil {
		json.Unmarshal(req.Params, &params)
	}

	if params.Raw == "" {
		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRawPatchRequired)))
		return
	}

	// Optimistic concurrency
	if params.BaseHash != "" && params.BaseHash != m.cfg.Hash() {
		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgConfigHashMismatch)))
		return
	}

	// Start from a locked current-config snapshot as base.
	merged := m.cfg.Clone()

	// Apply patch on top
	if err := json5.Unmarshal([]byte(params.Raw), merged); err != nil {
		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidRequest, err.Error())))
		return
	}

	// Extract secrets → save to config_secrets table, strip all from file
	m.saveSecretsToStore(ctx, merged)
	merged.StripSecrets()

	// Save to disk
	if err := config.Save(m.cfgPath, merged); err != nil {
		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToSave, "config", err.Error())))
		return
	}

	// Update in-memory config and restore secrets
	m.cfg.ReplaceFrom(merged)
	if m.secretsStore != nil {
		if secrets, err := m.secretsStore.GetAll(ctx); err == nil {
			m.cfg.ApplyDBSecrets(secrets)
		}
	}
	m.cfg.ApplyEnvOverrides()
	m.syncToSystemConfigs(ctx)
	m.broadcastChanged()
	emitAudit(m.eventBus, client, "config.patched", "config", "gateway")

	client.SendResponse(protocol.NewOKResponse(req.ID, map[string]any{
		"ok":      true,
		"path":    m.cfgPath,
		"config":  m.cfg.MaskedCopy(),
		"hash":    m.cfg.Hash(),
		"restart": false,
	}))
}

// syncToSystemConfigs syncs the resolved config to system_configs table for the given tenant.
func (m *ConfigMethods) syncToSystemConfigs(ctx context.Context) {
	if m.syncFn != nil {
		m.syncFn(ctx, m.cfg)
	}
}

// broadcastChanged notifies subscribers that config has been updated.
func (m *ConfigMethods) broadcastChanged() {
	if m.eventBus != nil {
		m.eventBus.Broadcast(bus.Event{Name: bus.TopicConfigChanged, Payload: m.cfg})
	}
}

// handleSchema returns the config JSON schema for UI form generation.
// Matching TS config.schema (src/gateway/server-methods/config.ts:276-289).
func (m *ConfigMethods) handleSchema(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
	schema := map[string]any{
		"type": "object",
		"properties": map[string]any{
			"agents": map[string]any{
				"type":        "object",
				"description": "Agent configuration (defaults + per-agent overrides)",
			},
			"channels": map[string]any{
				"type":        "object",
				"description": "Channel configuration (telegram, discord, slack, etc.)",
			},
			"providers": map[string]any{
				"type":        "object",
				"description": "AI provider API keys and settings",
			},
			"gateway": map[string]any{
				"type":        "object",
				"description": "Gateway server settings (host, port, token)",
			},
			"branding": map[string]any{
				"type":        "object",
				"description": "Public app branding and SEO metadata",
				"properties": map[string]any{
					"app_name": map[string]any{
						"type":        "string",
						"description": "Application name shown in browser metadata and UI chrome",
					},
					"app_short_name": map[string]any{
						"type":        "string",
						"description": "Short application name for compact surfaces",
					},
					"meta_title": map[string]any{
						"type":        "string",
						"description": "HTML document title override",
					},
					"meta_description": map[string]any{
						"type":        "string",
						"description": "HTML meta description override",
					},
					"meta_keywords": map[string]any{
						"type":        "string",
						"description": "HTML meta keywords override",
					},
					"logo_url": map[string]any{
						"type":        "string",
						"description": "Logo URL or uploaded /branding-assets/* path",
					},
					"favicon_url": map[string]any{
						"type":        "string",
						"description": "Favicon URL or uploaded /branding-assets/* path",
					},
					"apple_touch_icon_url": map[string]any{
						"type":        "string",
						"description": "Apple touch icon URL or uploaded /branding-assets/* path",
					},
					"og_title": map[string]any{
						"type":        "string",
						"description": "Open Graph title override",
					},
					"og_description": map[string]any{
						"type":        "string",
						"description": "Open Graph description override",
					},
					"og_image_url": map[string]any{
						"type":        "string",
						"description": "Open Graph image URL or uploaded /branding-assets/* path",
					},
					"theme_color": map[string]any{
						"type":        "string",
						"description": "Browser theme-color value",
					},
				},
			},
			"tools": map[string]any{
				"type":        "object",
				"description": "Tool configuration (browser, exec, web search)",
			},
			"skills": map[string]any{
				"type":        "object",
				"description": "Skill storage and upload settings",
				"properties": map[string]any{
					"max_upload_size_mb": map[string]any{
						"type":        "integer",
						"minimum":     config.MinSkillMaxUploadSizeMB,
						"maximum":     config.MaxSkillMaxUploadSizeMB,
						"default":     config.DefaultSkillMaxUploadSizeMB,
						"description": "Maximum skill ZIP upload size in MB",
					},
					"slash_commands": map[string]any{
						"type":        "object",
						"description": "Explicit slash command skill activation settings",
						"properties": map[string]any{
							"enabled": map[string]any{
								"type":        "boolean",
								"default":     true,
								"description": "Enable slash command detection in user prompts",
							},
							"suggest_not_found": map[string]any{
								"type":        "boolean",
								"default":     true,
								"description": "Suggest similar skills when a requested skill is not found",
							},
							"partial_matching": map[string]any{
								"type":        "boolean",
								"default":     false,
								"description": "Allow unique skill slug/name prefixes",
							},
							"prefix": map[string]any{
								"type":        "string",
								"default":     config.DefaultSkillSlashCommandPrefix,
								"description": "Single-character slash command prefix",
							},
						},
					},
				},
			},
			"sessions": map[string]any{
				"type":        "object",
				"description": "Session storage configuration",
			},
			"system_messages": map[string]any{
				"type":        "object",
				"description": "Custom operator-facing system messages sent outside normal LLM replies",
				"properties": map[string]any{
					"default_locale": map[string]any{
						"type":        "string",
						"enum":        []string{"en", "vi", "zh", "ko", "ru"},
						"description": "Default locale used when a channel caller does not provide a locale",
					},
					"messages": map[string]any{
						"type":        "object",
						"description": "Message template overrides keyed by message key and locale",
					},
				},
				"definitions": systemMessageSchemaDefinitions(),
			},
		},
	}

	client.SendResponse(protocol.NewOKResponse(req.ID, map[string]any{
		"json": schema,
	}))
}

func systemMessageSchemaDefinitions() []systemmessages.Definition {
	defaults := systemmessages.Defaults()
	keys := make([]string, 0, len(defaults))
	for key := range defaults {
		keys = append(keys, key)
	}
	slices.Sort(keys)

	defs := make([]systemmessages.Definition, 0, len(keys))
	for _, key := range keys {
		defs = append(defs, defaults[key])
	}
	return defs
}

// saveSecretsToStore extracts non-LLM/non-channel secrets from the config
// and persists them to the config_secrets table.
func (m *ConfigMethods) saveSecretsToStore(ctx context.Context, cfg *config.Config) {
	if m.secretsStore == nil {
		return
	}

	secrets := cfg.ExtractDBSecrets()
	for key, value := range secrets {
		if err := m.secretsStore.Set(ctx, key, value); err != nil {
			slog.Warn("failed to save config secret", "key", key, "error", err)
		}
	}
}