package main

import (
	"fmt"
	"log"
	"os"
	"path/filepath"
	"regexp"
	"strings"

	"verstak/internal/core/config"
)

// PluginDTO represents a discovered plugin with its current state.
type PluginDTO struct {
	Name        string      `json:"name"`
	Version     string      `json:"version"`
	Author      string      `json:"author,omitempty"`
	Description string      `json:"description,omitempty"`
	Active      bool        `json:"active"`
	Installed   bool        `json:"installed"`
	HasInstall  bool        `json:"hasInstall"`
	HasPanel    bool        `json:"hasPanel"`
	HasSettings bool        `json:"hasSettings"`
	UIContribs  UIContribDTO `json:"uiContribs"`
}

// UIContribDTO describes what a plugin adds to the UI.
type UIContribDTO struct {
	SidebarItems []SidebarItemDTO `json:"sidebarItems"`
	NodeTabs     []NodeTabDTO     `json:"nodeTabs"`
}

type SidebarItemDTO struct {
	ID    string `json:"id"`
	Label string `json:"label"`
	Icon  string `json:"icon,omitempty"`
}

type NodeTabDTO struct {
	ID    string `json:"id"`
	Label string `json:"label"`
	Page  string `json:"page"`
}

// ListPlugins returns all discovered plugins with their current enabled/disabled state.
func (a *App) ListPlugins() []PluginDTO {
	if a.plugins == nil {
		return nil
	}
	all := a.plugins.Plugins()
	out := make([]PluginDTO, 0, len(all))

	appCfg, _ := config.LoadAppConfig()
	enabledSet := make(map[string]bool)
	if appCfg != nil {
		for _, name := range appCfg.EnabledPlugins {
			enabledSet[name] = true
		}
	}

	for _, p := range all {
		active := enabledSet[p.Meta.Name] || p.Active
		contribs := UIContribDTO{}
		for _, item := range p.Meta.UI.SidebarItems {
			contribs.SidebarItems = append(contribs.SidebarItems, SidebarItemDTO{
				ID:    item.ID,
				Label: item.Label,
				Icon:  item.Icon,
			})
		}
		for _, tab := range p.Meta.UI.NodeTabs {
			contribs.NodeTabs = append(contribs.NodeTabs, NodeTabDTO{
				ID:    tab.ID,
				Label: tab.Label,
				Page:  tab.Page,
			})
		}

		hasPanel := false
		if p.Meta.Panel != "" {
			panelPath := filepath.Join(p.Dir, p.Meta.Panel)
			if _, err := os.Stat(panelPath); err == nil {
				hasPanel = true
			}
		}

		out = append(out, PluginDTO{
			Name:        p.Meta.Name,
			Version:     p.Meta.Version,
			Author:      p.Meta.Author,
			Description: p.Meta.Description,
			Active:      active,
			Installed:   p.Installed,
			HasInstall:  p.HasInstall,
			HasPanel:    hasPanel,
			UIContribs:  contribs,
		})
	}
	return out
}

// SetPluginEnabled persists the enabled/disabled state and applies it to the runtime.
// Enable: marks plugin as enabled, activates runtime, THEN persists to config (only on success).
// Disable: deactivates runtime, then marks plugin as disabled in config.
func (a *App) SetPluginEnabled(name string, enabled bool) error {
	if a.plugins == nil {
		return fmt.Errorf("plugin manager not ready")
	}

	if enabled {
		// Enable first (sets Enabled=true on the plugin struct)
		if err := a.plugins.Enable(name); err != nil {
			return err
		}
		// Activate runtime — if this fails, do NOT persist to config
		if err := a.plugins.ActivatePlugin(name); err != nil {
			// Rollback: deactivate runtime AND un-enable in-memory state
			a.plugins.DeactivatePlugin(name)
			a.plugins.Disable(name)
			return fmt.Errorf("activate %q: %w", name, err)
		}
		// Only persist to config after successful activation
		if err := a.saveEnabledPlugin(name); err != nil {
			// Config save failed — rollback runtime too
			a.plugins.DeactivatePlugin(name)
			a.plugins.Disable(name)
			return fmt.Errorf("save config for %q: %w", name, err)
		}
	} else {
		// Deactivate runtime first, then disable
		a.plugins.DeactivatePlugin(name)
		if err := a.plugins.Disable(name); err != nil {
			return err
		}
		// Remove from config
		if err := a.removeEnabledPlugin(name); err != nil {
			return fmt.Errorf("save config for %q: %w", name, err)
		}
	}

	return nil
}

// saveEnabledPlugin adds name to EnabledPlugins in config and saves.
func (a *App) saveEnabledPlugin(name string) error {
	appCfg, _ := config.LoadAppConfig()
	if appCfg == nil {
		appCfg = config.DefaultAppConfig()
	}
	for _, n := range appCfg.EnabledPlugins {
		if n == name {
			return nil // already present
		}
	}
	appCfg.EnabledPlugins = append(appCfg.EnabledPlugins, name)
	return config.SaveAppConfig(appCfg)
}

// removeEnabledPlugin removes name from EnabledPlugins in config and saves.
func (a *App) removeEnabledPlugin(name string) error {
	appCfg, _ := config.LoadAppConfig()
	if appCfg == nil {
		return nil // nothing to remove
	}
	var updated []string
	for _, n := range appCfg.EnabledPlugins {
		if n != name {
			updated = append(updated, n)
		}
	}
	appCfg.EnabledPlugins = updated
	return config.SaveAppConfig(appCfg)
}

// GetPluginPanelHTML returns the HTML panel content for a plugin.
// Validates that the panel path is safe: no absolute paths, no .. traversal,
// must be within the plugin directory, and must end with .html.
func (a *App) GetPluginPanelHTML(pluginName string) (string, error) {
	if a.plugins == nil {
		return "", fmt.Errorf("plugin manager not ready")
	}
	appCfg, _ := config.LoadAppConfig()
	enabledSet := make(map[string]bool)
	if appCfg != nil {
		for _, name := range appCfg.EnabledPlugins {
			enabledSet[name] = true
		}
	}
	for _, p := range a.plugins.Plugins() {
		active := enabledSet[p.Meta.Name] || p.Active
		if p.Meta.Name != pluginName || !active {
			continue
		}
		if p.Meta.Panel == "" {
			return "", nil
		}

		// Validate panel path: must be relative, no .., within plugin dir, .html only
		panel := p.Meta.Panel
		if filepath.IsAbs(panel) {
			return "", fmt.Errorf("panel path %q must be relative", panel)
		}
		if strings.Contains(panel, "..") {
			return "", fmt.Errorf("panel path %q must not contain ..", panel)
		}
		if !strings.HasSuffix(strings.ToLower(panel), ".html") {
			return "", fmt.Errorf("panel path %q must end with .html", panel)
		}

		// Resolve and verify the path is within the plugin directory
		panelPath := filepath.Join(p.Dir, panel)
		absPanel, err := filepath.Abs(panelPath)
		if err != nil {
			return "", fmt.Errorf("resolve panel path: %w", err)
		}
		absDir, err := filepath.Abs(p.Dir)
		if err != nil {
			return "", fmt.Errorf("resolve plugin dir: %w", err)
		}
		if !strings.HasPrefix(absPanel, absDir+string(filepath.Separator)) {
			return "", fmt.Errorf("panel path %q escapes plugin directory", panel)
		}

		data, err := os.ReadFile(absPanel)
		if err != nil {
			return "", fmt.Errorf("read panel %s: %w", panel, err)
		}
		return string(data), nil
	}
	return "", nil
}

// ListSystemViewsWithPlugins returns system views + plugin sidebar items.
func (a *App) ListSystemViewsWithPlugins() []SystemViewDTO {
	base := a.ListSystemViews()
	if a.plugins == nil {
		return base
	}

	appCfg, _ := config.LoadAppConfig()
	enabledSet := make(map[string]bool)
	if appCfg != nil {
		for _, name := range appCfg.EnabledPlugins {
			enabledSet[name] = true
		}
	}

	for _, p := range a.plugins.Plugins() {
		active := enabledSet[p.Meta.Name] || p.Active
		if !active {
			continue
		}
		for _, item := range p.Meta.UI.SidebarItems {
			pageID := "plugin:" + p.Meta.Name + ":" + item.ID
			base = append(base, SystemViewDTO{
				ID:    pageID,
				Label: item.Label,
				Icon:  item.Icon,
			})
		}
	}
	return base
}

// validLuaIdent matches a safe Lua identifier segment: [a-zA-Z_][a-zA-Z0-9_]*
var validLuaIdent = regexp.MustCompile(`^[a-zA-Z_][a-zA-Z0-9_]*$`)

// CallPluginFunction calls a global Lua function on an active plugin.
// The funcName can use dots: "calendar.create_event" → _G.calendar.create_event
// Only alphanumeric identifiers with underscores are allowed (no Lua injection).
// Returns JSON string or error.
func (a *App) CallPluginFunction(pluginName, funcName string, paramsJSON string) (string, error) {
	if a.plugins == nil {
		return "", fmt.Errorf("plugin manager not ready")
	}

	// Validate funcName: only [a-zA-Z0-9_.]+ allowed, each segment must be valid ident
	if funcName == "" {
		return "", fmt.Errorf("funcName is empty")
	}
	segments := strings.Split(funcName, ".")
	if len(segments) > 3 {
		return "", fmt.Errorf("funcName %q too deep (max 2 dots)", funcName)
	}
	for _, seg := range segments {
		if !validLuaIdent.MatchString(seg) {
			return "", fmt.Errorf("funcName %q contains invalid segment %q", funcName, seg)
		}
	}

	for _, p := range a.plugins.Plugins() {
		if p.Meta.Name != pluginName || !p.Active {
			continue
		}
		vm := p.VM()
		if vm == nil {
			continue
		}

		// Call via fully thread-safe LuaVM.CallFunctionJSON
		// (JSON→Lua conversion happens under vm.mu)
		return vm.CallFunctionJSON(segments, paramsJSON)
	}
	return "", fmt.Errorf("plugin %q not active or not found", pluginName)
}

// ReloadPlugins re-scans the plugins directory and re-initializes runtimes.
func (a *App) ReloadPlugins() error {
	if a.plugins == nil {
		return fmt.Errorf("plugin manager not ready")
	}
	log.Print("[plugins] reload requested")
	// Fully stop runtimes: schedulers first (they depend on VMs), then VMs
	a.plugins.StopSchedulers()
	a.plugins.CallShutdownHooks()
	a.plugins.CloseRuntimes()

	a.plugins.Discover()

	appCfg, _ := config.LoadAppConfig()
	a.plugins.SyncConfig(appCfg)

	a.plugins.InitRuntimes()
	a.plugins.CallInitHooks()
	a.plugins.StartSchedulers()
	log.Print("[plugins] reload complete")
	return nil
}

// InstallPlugin creates plugin's database tables and defaults via on_install hook.
// Does NOT activate the plugin — use SetPluginEnabled after.
func (a *App) InstallPlugin(name string) error {
	if a.plugins == nil {
		return fmt.Errorf("plugin manager not ready")
	}
	return a.plugins.Install(name)
}

// UninstallPlugin drops plugin's database tables and cleans data via on_uninstall hook.
// Disables the plugin first if active. Does NOT delete plugin files from disk.
func (a *App) UninstallPlugin(name string) error {
	if a.plugins == nil {
		return fmt.Errorf("plugin manager not ready")
	}
	return a.plugins.Uninstall(name)
}