package webui

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"log/slog"
	"os"
	"os/signal"
	"path/filepath"
	"strings"
	"syscall"
	"time"

	"bee/audit/internal/app"
	"bee/audit/internal/platform"
	"bee/audit/internal/runtimeenv"
)

type taskRunnerState struct {
	PID       int       `json:"pid"`
	Status    string    `json:"status"`
	Error     string    `json:"error,omitempty"`
	UpdatedAt time.Time `json:"updated_at"`
}

func taskRunnerStatePath(t *Task) string {
	if t == nil || strings.TrimSpace(t.ArtifactsDir) == "" {
		return ""
	}
	return filepath.Join(t.ArtifactsDir, "runner-state.json")
}

func writeTaskRunnerState(t *Task, state taskRunnerState) error {
	path := taskRunnerStatePath(t)
	if path == "" {
		return nil
	}
	if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
		return err
	}
	data, err := json.MarshalIndent(state, "", "  ")
	if err != nil {
		return err
	}
	tmp := path + ".tmp"
	if err := os.WriteFile(tmp, data, 0644); err != nil {
		return err
	}
	return os.Rename(tmp, path)
}

func readTaskRunnerState(t *Task) (taskRunnerState, bool) {
	path := taskRunnerStatePath(t)
	if path == "" {
		return taskRunnerState{}, false
	}
	data, err := os.ReadFile(path)
	if err != nil || len(data) == 0 {
		return taskRunnerState{}, false
	}
	var state taskRunnerState
	if err := json.Unmarshal(data, &state); err != nil {
		return taskRunnerState{}, false
	}
	return state, true
}

func processAlive(pid int) bool {
	if pid <= 0 {
		return false
	}
	err := syscall.Kill(pid, 0)
	return err == nil || err == syscall.EPERM
}

func finalizeTaskForResult(t *Task, errMsg string, cancelled bool) {
	now := time.Now()
	t.DoneAt = &now
	switch {
	case cancelled:
		t.Status = TaskCancelled
		t.ErrMsg = "aborted"
	case strings.TrimSpace(errMsg) != "":
		t.Status = TaskFailed
		t.ErrMsg = errMsg
	default:
		t.Status = TaskDone
		t.ErrMsg = ""
	}
}

func executeTaskWithOptions(opts *HandlerOptions, t *Task, j *jobState, ctx context.Context) {
	if opts == nil {
		j.append("ERROR: handler options not configured")
		j.finish("handler options not configured")
		return
	}
	a := opts.App

	recovered := len(j.lines) > 0
	j.append(fmt.Sprintf("Starting %s...", t.Name))
	if recovered {
		j.append(fmt.Sprintf("Recovered after bee-web restart at %s", time.Now().UTC().Format(time.RFC3339)))
	}

	var (
		archive string
		err     error
	)

	switch t.Target {
	case "nvidia":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		diagLevel := 2
		if t.params.StressMode {
			diagLevel = 3
		}
		if len(t.params.GPUIndices) > 0 || diagLevel > 0 {
			result, e := a.RunNvidiaAcceptancePackWithOptions(ctx, "", diagLevel, t.params.GPUIndices, j.append)
			if e != nil {
				err = e
			} else {
				archive = result.Body
			}
		} else {
			archive, err = a.RunNvidiaAcceptancePack("", j.append)
		}
	case "nvidia-targeted-stress":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		dur := t.params.Duration
		if dur <= 0 {
			dur = 300
		}
		archive, err = a.RunNvidiaTargetedStressValidatePack(ctx, "", dur, t.params.GPUIndices, j.append)
	case "nvidia-bench-perf":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		archive, err = a.RunNvidiaBenchmarkCtx(ctx, "", platform.NvidiaBenchmarkOptions{
			Profile:           t.params.BenchmarkProfile,
			SizeMB:            t.params.SizeMB,
			GPUIndices:        t.params.GPUIndices,
			ExcludeGPUIndices: t.params.ExcludeGPUIndices,
			RunNCCL:           t.params.RunNCCL,
			ParallelGPUs:      t.params.ParallelGPUs,
			RampStep:          t.params.RampStep,
			RampTotal:         t.params.RampTotal,
			RampRunID:         t.params.RampRunID,
		}, j.append)
	case "nvidia-bench-power":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		archive, err = a.RunNvidiaPowerBenchCtx(ctx, app.DefaultBeeBenchPowerDir, platform.NvidiaBenchmarkOptions{
			Profile:           t.params.BenchmarkProfile,
			GPUIndices:        t.params.GPUIndices,
			ExcludeGPUIndices: t.params.ExcludeGPUIndices,
			RampStep:          t.params.RampStep,
			RampTotal:         t.params.RampTotal,
			RampRunID:         t.params.RampRunID,
		}, j.append)
	case "nvidia-bench-autotune":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		archive, err = a.RunNvidiaPowerSourceAutotuneCtx(ctx, app.DefaultBeeBenchAutotuneDir, platform.NvidiaBenchmarkOptions{
			Profile: t.params.BenchmarkProfile,
			SizeMB:  t.params.SizeMB,
		}, t.params.BenchmarkKind, j.append)
	case "nvidia-compute":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		dur := t.params.Duration
		if t.params.BurnProfile != "" && dur <= 0 {
			dur = resolveBurnPreset(t.params.BurnProfile).DurationSec
		}
		rampPlan, planErr := resolveNvidiaRampPlan(t.params.BurnProfile, t.params.StaggerGPUStart, t.params.GPUIndices)
		if planErr != nil {
			err = planErr
			break
		}
		if t.params.BurnProfile != "" && t.params.StaggerGPUStart && dur <= 0 {
			dur = rampPlan.DurationSec
		}
		if rampPlan.StaggerSeconds > 0 {
			j.append(fmt.Sprintf("NVIDIA staggered ramp-up enabled: %ds per GPU; post-ramp hold: %ds; total runtime: %ds", rampPlan.StaggerSeconds, dur, rampPlan.TotalDurationSec))
		}
		archive, err = a.RunNvidiaOfficialComputePack(ctx, "", dur, t.params.GPUIndices, rampPlan.StaggerSeconds, j.append)
	case "nvidia-targeted-power":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		dur := t.params.Duration
		if t.params.BurnProfile != "" && dur <= 0 {
			dur = resolveBurnPreset(t.params.BurnProfile).DurationSec
		}
		archive, err = a.RunNvidiaTargetedPowerPack(ctx, "", dur, t.params.GPUIndices, j.append)
	case "nvidia-pulse":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		dur := t.params.Duration
		if t.params.BurnProfile != "" && dur <= 0 {
			dur = resolveBurnPreset(t.params.BurnProfile).DurationSec
		}
		archive, err = a.RunNvidiaPulseTestPack(ctx, "", dur, t.params.GPUIndices, j.append)
	case "nvidia-bandwidth":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		archive, err = a.RunNvidiaBandwidthPack(ctx, "", t.params.GPUIndices, j.append)
	case "nvidia-interconnect":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		archive, err = a.RunNCCLTests(ctx, "", t.params.GPUIndices, j.append)
	case "nvidia-stress":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		dur := t.params.Duration
		if t.params.BurnProfile != "" && dur <= 0 {
			dur = resolveBurnPreset(t.params.BurnProfile).DurationSec
		}
		rampPlan, planErr := resolveNvidiaRampPlan(t.params.BurnProfile, t.params.StaggerGPUStart, t.params.GPUIndices)
		if planErr != nil {
			err = planErr
			break
		}
		if t.params.BurnProfile != "" && t.params.StaggerGPUStart && dur <= 0 {
			dur = rampPlan.DurationSec
		}
		if rampPlan.StaggerSeconds > 0 {
			j.append(fmt.Sprintf("NVIDIA staggered ramp-up enabled: %ds per GPU; post-ramp hold: %ds; total runtime: %ds", rampPlan.StaggerSeconds, dur, rampPlan.TotalDurationSec))
		}
		archive, err = runNvidiaStressPackCtx(a, ctx, "", platform.NvidiaStressOptions{
			DurationSec:       dur,
			Loader:            t.params.Loader,
			GPUIndices:        t.params.GPUIndices,
			ExcludeGPUIndices: t.params.ExcludeGPUIndices,
			StaggerSeconds:    rampPlan.StaggerSeconds,
		}, j.append)
	case "memory":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		sizeMB, passes := resolveMemoryValidatePreset(t.params.BurnProfile, t.params.StressMode)
		j.append(fmt.Sprintf("Memory validate preset: %d MB x %d pass(es)", sizeMB, passes))
		archive, err = runMemoryAcceptancePackCtx(a, ctx, "", sizeMB, passes, j.append)
	case "storage":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		archive, err = runStorageAcceptancePackCtx(a, ctx, "", t.params.StressMode, j.append)
	case "cpu":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		dur := t.params.Duration
		if t.params.BurnProfile != "" && dur <= 0 {
			dur = resolveBurnPreset(t.params.BurnProfile).DurationSec
		}
		if dur <= 0 {
			if t.params.StressMode {
				dur = 1800
			} else {
				dur = 60
			}
		}
		j.append(fmt.Sprintf("CPU stress duration: %ds", dur))
		archive, err = runCPUAcceptancePackCtx(a, ctx, "", dur, j.append)
	case "amd":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		archive, err = runAMDAcceptancePackCtx(a, ctx, "", j.append)
	case "amd-mem":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		archive, err = runAMDMemIntegrityPackCtx(a, ctx, "", j.append)
	case "amd-bandwidth":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		archive, err = runAMDMemBandwidthPackCtx(a, ctx, "", j.append)
	case "amd-stress":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		dur := t.params.Duration
		if t.params.BurnProfile != "" && dur <= 0 {
			dur = resolveBurnPreset(t.params.BurnProfile).DurationSec
		}
		archive, err = runAMDStressPackCtx(a, ctx, "", dur, j.append)
	case "memory-stress":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		dur := t.params.Duration
		if t.params.BurnProfile != "" && dur <= 0 {
			dur = resolveBurnPreset(t.params.BurnProfile).DurationSec
		}
		archive, err = runMemoryStressPackCtx(a, ctx, "", dur, j.append)
	case "sat-stress":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		dur := t.params.Duration
		if t.params.BurnProfile != "" && dur <= 0 {
			dur = resolveBurnPreset(t.params.BurnProfile).DurationSec
		}
		archive, err = runSATStressPackCtx(a, ctx, "", dur, j.append)
	case "platform-stress":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		runOpts := resolvePlatformStressPreset(t.params.BurnProfile)
		runOpts.Components = t.params.PlatformComponents
		archive, err = a.RunPlatformStress(ctx, "", runOpts, j.append)
	case "audit":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		result, e := a.RunAuditNow(opts.RuntimeMode)
		if e != nil {
			err = e
		} else {
			for _, line := range splitLines(result.Body) {
				j.append(line)
			}
		}
	case "support-bundle":
		j.append("Building support bundle...")
		archive, err = buildSupportBundle(opts.ExportDir)
	case "install":
		if strings.TrimSpace(t.params.Device) == "" {
			err = fmt.Errorf("device is required")
			break
		}
		installLogPath := platform.InstallLogPath(t.params.Device)
		j.append("Install log: " + installLogPath)
		err = streamCmdJob(j, installCommand(ctx, t.params.Device, installLogPath))
	case "install-to-ram":
		if a == nil {
			err = fmt.Errorf("app not configured")
			break
		}
		err = a.RunInstallToRAM(ctx, j.append)
	default:
		j.append("ERROR: unknown target: " + t.Target)
		j.finish("unknown target")
		return
	}

	if archive != "" {
		archivePath := app.ExtractArchivePath(archive)
		if err == nil && app.ReadSATOverallStatus(archivePath) == "FAILED" {
			err = fmt.Errorf("SAT overall_status=FAILED (see summary.txt)")
		}
		if opts.App != nil && opts.App.StatusDB != nil {
			app.ApplySATResultToDB(opts.App.StatusDB, t.Target, archivePath)
		}
	}

	if err != nil {
		if ctx.Err() != nil {
			j.append("Aborted.")
			j.finish("aborted")
		} else {
			j.append("ERROR: " + err.Error())
			j.finish(err.Error())
		}
		return
	}
	if archive != "" {
		j.append("Archive: " + archive)
	}
	j.finish("")
}

func loadPersistedTask(statePath, taskID string) (*Task, error) {
	data, err := os.ReadFile(statePath)
	if err != nil {
		return nil, err
	}
	var persisted []persistedTask
	if err := json.Unmarshal(data, &persisted); err != nil {
		return nil, err
	}
	for _, pt := range persisted {
		if pt.ID != taskID {
			continue
		}
		t := &Task{
			ID:             pt.ID,
			Name:           pt.Name,
			Target:         pt.Target,
			Priority:       pt.Priority,
			Status:         pt.Status,
			CreatedAt:      pt.CreatedAt,
			StartedAt:      pt.StartedAt,
			DoneAt:         pt.DoneAt,
			ErrMsg:         pt.ErrMsg,
			LogPath:        pt.LogPath,
			ArtifactsDir:   pt.ArtifactsDir,
			ReportJSONPath: pt.ReportJSONPath,
			ReportHTMLPath: pt.ReportHTMLPath,
			params:         pt.Params,
		}
		ensureTaskReportPaths(t)
		return t, nil
	}
	return nil, fmt.Errorf("task %s not found", taskID)
}

func RunPersistedTask(exportDir, taskID string, stdout, stderr io.Writer) int {
	if strings.TrimSpace(exportDir) == "" || strings.TrimSpace(taskID) == "" {
		fmt.Fprintln(stderr, "bee task-run: --export-dir and --task-id are required")
		return 2
	}

	runtimeInfo, err := runtimeenv.Detect("auto")
	if err != nil {
		slog.Warn("resolve runtime for task-run", "err", err)
	}
	opts := &HandlerOptions{
		ExportDir:   exportDir,
		App:         app.New(platform.New()),
		RuntimeMode: runtimeInfo.Mode,
	}
	statePath := filepath.Join(exportDir, "tasks-state.json")
	task, err := loadPersistedTask(statePath, taskID)
	if err != nil {
		fmt.Fprintln(stderr, err.Error())
		return 1
	}
	if task.StartedAt == nil || task.StartedAt.IsZero() {
		now := time.Now()
		task.StartedAt = &now
	}
	if task.Status == "" {
		task.Status = TaskRunning
	}
	if err := writeTaskRunnerState(task, taskRunnerState{
		PID:       os.Getpid(),
		Status:    TaskRunning,
		UpdatedAt: time.Now().UTC(),
	}); err != nil {
		fmt.Fprintln(stderr, err.Error())
		return 1
	}

	ctx, cancel := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
	defer cancel()

	j := newTaskJobState(task.LogPath, taskSerialPrefix(task))
	executeTaskWithOptions(opts, task, j, ctx)
	finalizeTaskForResult(task, j.err, ctx.Err() != nil)
	if err := writeTaskReportArtifacts(task); err != nil {
		appendJobLog(task.LogPath, "WARN: task report generation failed: "+err.Error())
	}
	j.closeLog()
	if err := writeTaskRunnerState(task, taskRunnerState{
		PID:       os.Getpid(),
		Status:    task.Status,
		Error:     task.ErrMsg,
		UpdatedAt: time.Now().UTC(),
	}); err != nil {
		fmt.Fprintln(stderr, err.Error())
	}
	if task.ErrMsg != "" {
		return 1
	}
	return 0
}