// Package tasks provides task processing implementations.
package tasks

import (
	"errors"
	"fmt"
	"jiggablend/internal/runner/api"
	"jiggablend/internal/runner/blender"
	"jiggablend/internal/runner/encoding"
	"jiggablend/internal/runner/workspace"
	"jiggablend/pkg/executils"
	"jiggablend/pkg/types"
	"os/exec"
	"sync"
	"time"
)

// Processor handles a specific task type.
type Processor interface {
	Process(ctx *Context) error
}

// Context provides task execution context.
type Context struct {
	TaskID   int64
	JobID    int64
	JobName  string
	Frame    int // frame start (inclusive); kept for backward compat
	FrameEnd int // frame end (inclusive); same as Frame for single-frame
	TaskType string
	WorkDir  string
	JobToken string
	Metadata *types.BlendMetadata

	Manager   *api.ManagerClient
	JobConn   *api.JobConnection
	Workspace *workspace.Manager
	Blender   *blender.Manager
	Encoder   *encoding.Selector
	Processes *executils.ProcessTracker
}

// ErrJobCancelled indicates the manager-side job was cancelled during execution.
var ErrJobCancelled = errors.New("job cancelled")

// NewContext creates a new task context. frameEnd should be >= frame; if 0 or less than frame, it is treated as single-frame (frameEnd = frame).
func NewContext(
	taskID, jobID int64,
	jobName string,
	frameStart, frameEnd int,
	taskType string,
	workDir string,
	jobToken string,
	metadata *types.BlendMetadata,
	manager *api.ManagerClient,
	jobConn *api.JobConnection,
	ws *workspace.Manager,
	blenderMgr *blender.Manager,
	encoder *encoding.Selector,
	processes *executils.ProcessTracker,
) *Context {
	if frameEnd < frameStart {
		frameEnd = frameStart
	}
	return &Context{
		TaskID:    taskID,
		JobID:     jobID,
		JobName:   jobName,
		Frame:     frameStart,
		FrameEnd:  frameEnd,
		TaskType:  taskType,
		WorkDir:   workDir,
		JobToken:  jobToken,
		Metadata:  metadata,
		Manager:   manager,
		JobConn:   jobConn,
		Workspace: ws,
		Blender:   blenderMgr,
		Encoder:   encoder,
		Processes: processes,
	}
}

// Log sends a log entry to the manager.
func (c *Context) Log(level types.LogLevel, message string) {
	if c.JobConn != nil {
		c.JobConn.Log(c.TaskID, level, message)
	}
}

// Info logs an info message.
func (c *Context) Info(message string) {
	c.Log(types.LogLevelInfo, message)
}

// Warn logs a warning message.
func (c *Context) Warn(message string) {
	c.Log(types.LogLevelWarn, message)
}

// Error logs an error message.
func (c *Context) Error(message string) {
	c.Log(types.LogLevelError, message)
}

// Progress sends a progress update.
func (c *Context) Progress(progress float64) {
	if c.JobConn != nil {
		c.JobConn.Progress(c.TaskID, progress)
	}
}

// OutputUploaded notifies that an output file was uploaded.
func (c *Context) OutputUploaded(fileName string) {
	if c.JobConn != nil {
		c.JobConn.OutputUploaded(c.TaskID, fileName)
	}
}

// Complete sends task completion.
func (c *Context) Complete(success bool, errorMsg error) {
	if c.JobConn != nil {
		c.JobConn.Complete(c.TaskID, success, errorMsg)
	}
}

// GetOutputFormat returns the output format from metadata or default.
func (c *Context) GetOutputFormat() string {
	if c.Metadata != nil && c.Metadata.RenderSettings.OutputFormat != "" {
		return c.Metadata.RenderSettings.OutputFormat
	}
	return "PNG"
}

// GetFrameRate returns the frame rate from metadata or default.
func (c *Context) GetFrameRate() float64 {
	if c.Metadata != nil && c.Metadata.RenderSettings.FrameRate > 0 {
		return c.Metadata.RenderSettings.FrameRate
	}
	return 24.0
}

// GetBlenderVersion returns the Blender version from metadata.
func (c *Context) GetBlenderVersion() string {
	if c.Metadata != nil {
		return c.Metadata.BlenderVersion
	}
	return ""
}

// ShouldUnhideObjects returns whether to unhide objects.
func (c *Context) ShouldUnhideObjects() bool {
	return c.Metadata != nil && c.Metadata.UnhideObjects != nil && *c.Metadata.UnhideObjects
}

// ShouldEnableExecution returns whether to enable auto-execution.
func (c *Context) ShouldEnableExecution() bool {
	return c.Metadata != nil && c.Metadata.EnableExecution != nil && *c.Metadata.EnableExecution
}

// IsJobCancelled checks whether the manager marked this job as cancelled.
func (c *Context) IsJobCancelled() (bool, error) {
	if c.Manager == nil {
		return false, nil
	}
	status, err := c.Manager.GetJobStatus(c.JobID)
	if err != nil {
		return false, err
	}
	return status == types.JobStatusCancelled, nil
}

// CheckCancelled returns ErrJobCancelled if the job was cancelled.
func (c *Context) CheckCancelled() error {
	cancelled, err := c.IsJobCancelled()
	if err != nil {
		return fmt.Errorf("failed to check job status: %w", err)
	}
	if cancelled {
		return ErrJobCancelled
	}
	return nil
}

// StartCancellationMonitor polls manager status and kills cmd if job is cancelled.
// Caller must invoke returned stop function when cmd exits.
func (c *Context) StartCancellationMonitor(cmd *exec.Cmd, taskLabel string) func() {
	stop := make(chan struct{})
	var once sync.Once

	go func() {
		ticker := time.NewTicker(2 * time.Second)
		defer ticker.Stop()

		for {
			select {
			case <-stop:
				return
			case <-ticker.C:
				cancelled, err := c.IsJobCancelled()
				if err != nil {
					c.Warn(fmt.Sprintf("Could not check cancellation for %s task: %v", taskLabel, err))
					continue
				}
				if !cancelled {
					continue
				}
				c.Warn(fmt.Sprintf("Job %d was cancelled, stopping %s task early", c.JobID, taskLabel))
				if cmd != nil && cmd.Process != nil {
					_ = cmd.Process.Kill()
				}
				return
			}
		}
	}()

	return func() {
		once.Do(func() {
			close(stop)
		})
	}
}