//go:build linux

package blocker

import (
	"fmt"
	"log"
	"os"
	"path/filepath"
	"strconv"
	"strings"
)

var systemAllowed = map[string]bool{
	"gnome-shell":        true,
	"mutter":             true,
	"xterm":              true,
	"gnome-terminal":     true,
	"konsole":            true,
	"ptyxis":             true, // Ubuntu terminal
	"bash":               true,
	"zsh":                true,
	"sh":                 true,
	"wails":              true,
	"code":               true,
	"cursor":             true,
	"windsurf":           true,
	"goland":             true,
	"idea":               true,
	"client":             true,
	"simple_care_v1.0":   true,
	"xwayland":           true,
	"mutter-x11-fram":    true,
	"ibus-x11":           true,
	"ibus-daemon":        true,
	"gsd-":               true, // prefix
	"ibus-":              true, // prefix
	"xdg-":               true, // prefix
	"at-spi":             true, // prefix
	"evolution-":         true, // prefix
	"goa-daemon":         true,
	"gjs":                true,
	"snapd-":             true, // prefix
	"systemd":            true,
	"webkit":             true, // WebKit subprocesses
	"glycin":             true, // GNOME image helper
	"zenity":             true, // Dialog utility
	"rustdesk":           true, // Remote support safety
	"rustdesk-bin":       true,
	"anydesk":            true,
	"teamviewer":         true,
	"remmina":            true,
}

func isSystemAllowed(name string) bool {
	name = strings.ToLower(name)
	if systemAllowed[name] {
		return true
	}
	for pattern := range systemAllowed {
		if strings.HasPrefix(name, pattern) && pattern != name {
			return true
		}
	}
	return false
}

func getPPID(pid uint32) uint32 {
	statusBytes, err := os.ReadFile(fmt.Sprintf("/proc/%d/status", pid))
	if err != nil {
		return 0
	}
	lines := strings.Split(string(statusBytes), "\n")
	for _, line := range lines {
		if strings.HasPrefix(line, "PPid:") {
			parts := strings.Fields(line)
			if len(parts) >= 2 {
				if ppid, err := strconv.ParseUint(parts[1], 10, 32); err == nil {
					return uint32(ppid)
				}
			}
		}
	}
	return 0
}

func isDescendantOf(pid, targetPid uint32) bool {
	curr := pid
	for i := 0; i < 10; i++ { // limits lookup to 10 ancestor levels
		ppid := getPPID(curr)
		if ppid == 0 {
			return false
		}
		if ppid == targetPid {
			return true
		}
		curr = ppid
	}
	return false
}

type ProcessInfo struct {
	PID  uint32
	Name string
}

func getVisibleProcesses() (map[uint32]ProcessInfo, error) {
	files, err := os.ReadDir("/proc")
	if err != nil {
		return nil, err
	}

	procs := make(map[uint32]ProcessInfo)
	for _, f := range files {
		if !f.IsDir() {
			continue
		}
		pid, err := strconv.ParseUint(f.Name(), 10, 32)
		if err != nil {
			continue
		}

		mapsPath := fmt.Sprintf("/proc/%d/maps", pid)
		mapsBytes, err := os.ReadFile(mapsPath)
		if err != nil {
			// Skip processes we don't own (permission denied)
			continue
		}

		mapsStr := string(mapsBytes)
		isGUI := strings.Contains(mapsStr, "libgtk") ||
			strings.Contains(mapsStr, "libQt") ||
			strings.Contains(mapsStr, "libX11") ||
			strings.Contains(mapsStr, "libwayland-client")

		if !isGUI {
			continue
		}

		// Read process name from /proc/PID/comm
		commBytes, err := os.ReadFile(fmt.Sprintf("/proc/%d/comm", pid))
		if err != nil {
			continue
		}
		procName := strings.TrimSpace(string(commBytes))

		if procName != "" {
			procs[uint32(pid)] = ProcessInfo{
				PID:  uint32(pid),
				Name: procName,
			}
		}
	}

	return procs, nil
}

func (b *Blocker) checkAndKill() {
	b.mu.Lock()
	keywords := make([]string, len(b.allowedKeywords))
	copy(keywords, b.allowedKeywords)
	b.mu.Unlock()

	if len(keywords) == 0 {
		return
	}

	currentExec := ""
	if execPath, err := os.Executable(); err == nil {
		currentExec = strings.ToLower(filepath.Base(execPath))
	}

	procs, err := getVisibleProcesses()
	if err != nil {
		log.Printf("[BLOCKER] Failed to get visible processes: %v", err)
		return
	}

	myPid := uint32(os.Getpid())
	for pid, info := range procs {
		pNameLower := strings.ToLower(info.Name)

		// 1. Always allow our app, our sub-processes, system/critical developer tools, or agent helpers
		isOurSubprocess := pid == myPid || isDescendantOf(pid, myPid)
		isAntigravity := strings.Contains(pNameLower, "antigravity")
		if isOurSubprocess || (currentExec != "" && pNameLower == currentExec) || isSystemAllowed(pNameLower) || isAntigravity {
			continue
		}

		// 2. Check if the process name contains any allowed keywords
		allowed := false
		for _, kw := range keywords {
			if matchesAllowedKeyword(kw, pNameLower, pNameLower) {
				allowed = true
				break
			}
		}

		// 3. If not allowed, kill the application
		if !allowed {
			if b.OnBlocked != nil {
				b.OnBlocked(info.Name, info.Name)
			}
			log.Printf("[BLOCKER] KILLED unauthorized application: %s (PID: %d)", info.Name, pid)
			proc, err := os.FindProcess(int(pid))
			if err == nil {
				errKill := proc.Kill()
				if errKill == nil && b.OnKill != nil {
					b.OnKill(info.Name, info.Name)
				}
			}
		}
	}
}