// Package runner executes PowerShell deployment scripts and streams log output.
package runner

import (
	"bufio"
	"context"
	"encoding/json"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"time"
)

// Step describes a single deployment step.
type Step struct {
	ID         string // e.g. "adminAccount"
	Num        string // display number e.g. "00"
	Name       string
	ScriptName string // e.g. "00-admin-account.ps1"
	Enabled    bool
}

// AllSteps returns the ordered list of deployment steps.
func AllSteps() []Step {
	return []Step{
		{ID: "adminAccount",    Num: "00", Name: "Admin ucet",              ScriptName: "00-admin-account.ps1"},
		{ID: "bloatware",       Num: "01", Name: "Bloatware removal",        ScriptName: "01-bloatware.ps1"},
		{ID: "software",        Num: "02", Name: "Software (winget)",         ScriptName: "02-software.ps1"},
		{ID: "systemRegistry",  Num: "03", Name: "System Registry (HKLM)",   ScriptName: "03-system-registry.ps1"},
		{ID: "defaultProfile",  Num: "04", Name: "Default Profile",          ScriptName: "04-default-profile.ps1"},
		{ID: "personalization", Num: "05", Name: "Personalizace",             ScriptName: "05-personalization.ps1"},
		{ID: "scheduledTasks",  Num: "06", Name: "Scheduled Tasks",           ScriptName: "06-scheduled-tasks.ps1"},
		{ID: "backinfo",        Num: "07", Name: "BackInfo",                  ScriptName: "07-backinfo.ps1"},
		{ID: "activation",      Num: "08", Name: "Windows aktivace",          ScriptName: "08-activation.ps1"},
		{ID: "network",         Num: "09", Name: "Network discovery",         ScriptName: "10-network.ps1"},
		{ID: "pcIdentity",      Num: "10", Name: "PC identita",               ScriptName: "09-pc-identity.ps1"},
	}
}

// RunConfig holds runtime parameters passed to each script.
type RunConfig struct {
	ScriptsDir  string
	ConfigPath  string
	LogFile     string
	ProfileType string
}

// Result is the outcome of a single step.
type Result struct {
	Step    Step
	Status  string // "OK", "ERROR", "SKIPPED"
	Elapsed time.Duration
}

// LogLine is a single output line from a running script.
type LogLine struct {
	StepID string
	Text   string
	Level  string // INFO, OK, ERROR, WARN, STEP - parsed from [LEVEL] prefix
}

// Runner executes deployment steps sequentially.
type Runner struct {
	cfg      RunConfig
	onLog    func(LogLine)
	onResult func(Result)
	cancel   context.CancelFunc
}

// New creates a Runner. onLog is called for each output line, onResult after each step.
func New(cfg RunConfig, onLog func(LogLine), onResult func(Result)) *Runner {
	return &Runner{cfg: cfg, onLog: onLog, onResult: onResult}
}

// Run executes enabled steps sequentially. Blocks until done or context cancelled.
func (r *Runner) Run(ctx context.Context, steps []Step) []Result {
	ctx, cancel := context.WithCancel(ctx)
	r.cancel = cancel
	defer cancel()

	// Write config JSON to temp file so scripts can read it
	cfgArg := r.cfg.ConfigPath

	var results []Result
	for _, step := range steps {
		if !step.Enabled {
			res := Result{Step: step, Status: "SKIPPED"}
			r.onResult(res)
			results = append(results, res)
			continue
		}

		start := time.Now()
		err := r.runScript(ctx, step, cfgArg)
		elapsed := time.Since(start)

		status := "OK"
		if err != nil {
			if ctx.Err() != nil {
				status = "CANCELLED"
			} else {
				status = "ERROR"
			}
		}

		res := Result{Step: step, Status: status, Elapsed: elapsed}
		r.onResult(res)
		results = append(results, res)

		if ctx.Err() != nil {
			break
		}
	}
	return results
}

// Stop cancels the running deployment.
func (r *Runner) Stop() {
	if r.cancel != nil {
		r.cancel()
	}
}

func (r *Runner) runScript(ctx context.Context, step Step, cfgArg string) error {
	scriptPath := filepath.Join(r.cfg.ScriptsDir, step.ScriptName)

	// Build argument list
	args := []string{
		"-NonInteractive",
		"-ExecutionPolicy", "Bypass",
		"-File", scriptPath,
		"-LogFile", r.cfg.LogFile,
	}

	// Pass config object as JSON string (script reads it inline)
	if cfgArg != "" {
		args = append(args, "-Config", fmt.Sprintf("(Get-Content '%s' | ConvertFrom-Json)", cfgArg))
	}

	// ProfileType for step 04
	if step.ID == "defaultProfile" && r.cfg.ProfileType != "" {
		args = append(args, "-ProfileType", r.cfg.ProfileType)
	}

	cmd := exec.CommandContext(ctx, "powershell.exe", args...)

	stdout, err := cmd.StdoutPipe()
	if err != nil {
		return err
	}
	cmd.Stderr = cmd.Stdout // merge stderr into stdout

	if err := cmd.Start(); err != nil {
		return err
	}

	scanner := bufio.NewScanner(stdout)
	for scanner.Scan() {
		line := scanner.Text()
		r.onLog(LogLine{
			StepID: step.ID,
			Text:   line,
			Level:  parseLevel(line),
		})
	}

	return cmd.Wait()
}

// parseLevel extracts the log level from lines formatted as "[HH:mm:ss] [LEVEL] message".
func parseLevel(line string) string {
	if strings.Contains(line, "] [OK]") {
		return "OK"
	}
	if strings.Contains(line, "] [ERROR]") {
		return "ERROR"
	}
	if strings.Contains(line, "] [WARN]") {
		return "WARN"
	}
	if strings.Contains(line, "] [STEP]") {
		return "STEP"
	}
	return "INFO"
}

// ExtractScripts unpacks embedded scripts to a temp directory.
// Returns the directory path. Caller is responsible for cleanup.
func ExtractScripts(fs interface{ ReadDir(string) ([]os.DirEntry, error); ReadFile(string) ([]byte, error) }, tmpDir string) error {
	entries, err := fs.ReadDir("scripts")
	if err != nil {
		return fmt.Errorf("read embedded scripts: %w", err)
	}
	scriptsDir := filepath.Join(tmpDir, "scripts")
	if err := os.MkdirAll(scriptsDir, 0755); err != nil {
		return err
	}
	for _, e := range entries {
		if e.IsDir() {
			continue
		}
		data, err := fs.ReadFile(filepath.Join("scripts", e.Name()))
		if err != nil {
			return err
		}
		if err := os.WriteFile(filepath.Join(scriptsDir, e.Name()), data, 0644); err != nil {
			return err
		}
	}
	return nil
}

// ExtractAssets unpacks embedded assets to tmpDir/assets.
func ExtractAssets(fs interface{ ReadDir(string) ([]os.DirEntry, error); ReadFile(string) ([]byte, error) }, tmpDir string) error {
	return extractDir(fs, "assets", tmpDir)
}

func extractDir(fs interface{ ReadDir(string) ([]os.DirEntry, error); ReadFile(string) ([]byte, error) }, src, dstBase string) error {
	entries, err := fs.ReadDir(src)
	if err != nil {
		return err
	}
	dst := filepath.Join(dstBase, src)
	if err := os.MkdirAll(dst, 0755); err != nil {
		return err
	}
	for _, e := range entries {
		srcPath := filepath.Join(src, e.Name())
		dstPath := filepath.Join(dstBase, srcPath)
		if e.IsDir() {
			if err := extractDir(fs, srcPath, dstBase); err != nil {
				return err
			}
			continue
		}
		data, err := fs.ReadFile(srcPath)
		if err != nil {
			return err
		}
		if err := os.WriteFile(dstPath, data, 0644); err != nil {
			return err
		}
	}
	return nil
}

// WriteConfig serialises cfg to a temp JSON file and returns its path.
func WriteConfig(cfg interface{}, tmpDir string) (string, error) {
	path := filepath.Join(tmpDir, "config-runtime.json")
	data, err := json.MarshalIndent(cfg, "", "  ")
	if err != nil {
		return "", err
	}
	return path, os.WriteFile(path, data, 0644)
}