package main

import (
	"bufio"
	"fmt"
	"os"
	"path/filepath"
	"strconv"
	"strings"

	i3 "go.i3wm.org/i3/v4"
)

const maxPPIDDepth = 20

// X11PIDResolver abstrait la lecture de _NET_WM_PID pour testabilite.
type X11PIDResolver interface {
	GetPID(windowID int64) (int, error)
}

// I3TreeProvider abstrait i3.GetTree() pour testabilite.
type I3TreeProvider interface {
	GetTree() (i3.Tree, error)
}

// ReadPPID lit le PPid depuis /proc/PID/status. procDir injectable pour les tests.
func ReadPPID(procDir string, pid int) (int, error) {
	statusPath := filepath.Join(procDir, strconv.Itoa(pid), "status")
	f, err := os.Open(statusPath)
	if err != nil {
		return 0, err
	}
	defer f.Close()

	scanner := bufio.NewScanner(f)
	for scanner.Scan() {
		line := scanner.Text()
		if strings.HasPrefix(line, "PPid:") {
			fields := strings.Fields(line)
			if len(fields) < 2 {
				return 0, fmt.Errorf("malformed PPid line: %q", line)
			}
			return strconv.Atoi(fields[1])
		}
	}
	return 0, fmt.Errorf("PPid not found in %s", statusPath)
}

// ResolveWorkspace remonte la chaine PPID depuis claudePID jusqu'a trouver
// un PID connu dans terminalWorkspaces. Max 20 niveaux pour eviter les boucles.
func ResolveWorkspace(procDir string, claudePID int, terminalWorkspaces map[int]string) string {
	current := claudePID
	for depth := 0; depth < maxPPIDDepth; depth++ {
		ppid, err := ReadPPID(procDir, current)
		if err != nil || ppid <= 0 {
			return ""
		}
		if ws, ok := terminalWorkspaces[ppid]; ok {
			return ws
		}
		current = ppid
	}
	return ""
}

// BuildTerminalWorkspaceMap construit la map terminalPID -> workspaceName
// en parcourant l'arbre i3 et en resolvant le PID via X11 _NET_WM_PID.
func BuildTerminalWorkspaceMap(tree I3TreeProvider, x11 X11PIDResolver) (map[int]string, error) {
	t, err := tree.GetTree()
	if err != nil {
		return nil, err
	}

	result := make(map[int]string)
	walkI3Tree(t.Root, "", x11, result)
	return result, nil
}

func walkI3Tree(node *i3.Node, currentWorkspace string, x11 X11PIDResolver, result map[int]string) {
	if node == nil {
		return
	}

	if node.Type == i3.WorkspaceNode {
		currentWorkspace = node.Name
	}

	if node.Window > 0 && currentWorkspace != "" {
		pid, err := x11.GetPID(node.Window)
		if err == nil && pid > 0 {
			result[pid] = currentWorkspace
		}
	}

	for _, child := range node.Nodes {
		walkI3Tree(child, currentWorkspace, x11, result)
	}
	for _, child := range node.FloatingNodes {
		walkI3Tree(child, currentWorkspace, x11, result)
	}
}