package cmd

import (
	"fmt"
	"os"
	"strings"
	"time"

	"git.jnss.me/joakim/opal/internal/engine"
	"github.com/google/uuid"
	"github.com/spf13/cobra"
)

var addCmd = &cobra.Command{
	Use:   "add <description> [modifiers...]",
	Short: "Add a new task",
	Long: `Add a new task with optional modifiers.

Examples:
  opal add buy groceries                          # No quotes needed!
  opal add review PR priority:H project:backend
  opal add buy groceries +shop carrots            # Tag can be anywhere
  opal add team meeting due:mon recur:1w +meetings`,
	Run: func(cmd *cobra.Command, args []string) {
		parsed := getParsedArgs(cmd)
		// For add, combine filters and modifiers (all are args to parse)
		allArgs := append(parsed.Filters, parsed.Modifiers...)
		if err := addTask(allArgs); err != nil {
			fmt.Fprintf(os.Stderr, "Error: %v\n", err)
			os.Exit(1)
		}
	},
}

func addTask(args []string) error {
	// Parse description and modifiers from args
	// Description = all words that are NOT filters/modifiers
	// Filters/Modifiers = words with +, -, or containing :
	description, modifierArgs, err := parseAddArgs(args)
	if err != nil {
		return err
	}

	// Parse modifiers
	var mod *engine.Modifier

	if len(modifierArgs) > 0 {
		mod, err = engine.ParseModifier(modifierArgs)
		if err != nil {
			return fmt.Errorf("failed to parse modifiers: %w", err)
		}
	}

	// Check if this is a recurring task
	isRecurring := mod != nil && mod.SetAttributes["recur"] != nil

	if isRecurring {
		// Create recurring task (template + first instance)
		return addRecurringTask(description, mod)
	}

	// Create regular task
	task, err := engine.CreateTaskWithModifier(description, mod)
	if err != nil {
		return fmt.Errorf("failed to create task: %w", err)
	}

	fmt.Printf("Created task %s\n", task.UUID)
	if len(task.Tags) > 0 {
		fmt.Printf("Tags: %s\n", strings.Join(task.Tags, ", "))
	}

	return nil
}

// parseAddArgs extracts description and modifiers from args
// Description = all non-filter/modifier words joined with spaces
// Filters/Modifiers = args with +, -, or containing :
func parseAddArgs(args []string) (string, []string, error) {
	var descParts []string
	var modifiers []string

	for _, arg := range args {
		isFilterOrModifier := strings.HasPrefix(arg, "+") ||
			strings.HasPrefix(arg, "-") ||
			strings.Contains(arg, ":")

		if isFilterOrModifier {
			modifiers = append(modifiers, arg)
		} else {
			descParts = append(descParts, arg)
		}
	}

	if len(descParts) == 0 {
		return "", nil, fmt.Errorf("description is required")
	}

	description := strings.Join(descParts, " ")
	return description, modifiers, nil
}

func addRecurringTask(description string, mod *engine.Modifier) error {
	// Extract recurrence pattern
	recurPattern := mod.SetAttributes["recur"]
	if recurPattern == nil {
		return fmt.Errorf("no recurrence pattern specified")
	}

	// Validate: recurring tasks must have due date
	if mod.SetAttributes["due"] == nil {
		return fmt.Errorf("recurring tasks require a due date (use due:YYYY-MM-DD or due:monday)")
	}

	duration, err := engine.ParseRecurrencePattern(*recurPattern)
	if err != nil {
		return fmt.Errorf("invalid recurrence pattern: %w", err)
	}

	// Create template task (without saving yet)
	now := time.Now()
	template := &engine.Task{
		UUID:               uuid.New(),
		Status:             engine.StatusRecurring,
		Description:        description,
		Priority:           engine.PriorityDefault,
		Created:            now,
		Modified:           now,
		RecurrenceDuration: &duration,
		Tags:               []string{},
	}

	// Create modifier without the recur attribute
	tempMod := &engine.Modifier{
		SetAttributes:  make(map[string]*string),
		AttributeOrder: []string{},
		AddTags:        mod.AddTags,
		RemoveTags:     mod.RemoveTags,
	}

	// Copy all attributes except recur
	for _, key := range mod.AttributeOrder {
		if key != "recur" {
			val := mod.SetAttributes[key]
			tempMod.SetAttributes[key] = val
			tempMod.AttributeOrder = append(tempMod.AttributeOrder, key)
		}
	}

	// Apply modifiers to template before first save
	if err := tempMod.ApplyToNew(template); err != nil {
		return fmt.Errorf("failed to apply modifiers to template: %w", err)
	}

	// Save template
	if err := template.Save(); err != nil {
		return fmt.Errorf("failed to save template: %w", err)
	}

	// Add tags to template (requires task.ID from save)
	for _, tag := range mod.AddTags {
		if err := template.AddTag(tag); err != nil {
			return fmt.Errorf("failed to add tag to template: %w", err)
		}
	}

	// Create first instance
	instance := &engine.Task{
		UUID:        uuid.New(),
		Status:      engine.StatusPending,
		Description: description,
		Priority:    template.Priority,
		Created:     now,
		Modified:    now,
		ParentUUID:  &template.UUID,
		Due:         template.Due,
		Wait:        template.Wait,
		Scheduled:   template.Scheduled,
		Project:     template.Project,
		Tags:        []string{},
	}

	if err := instance.Save(); err != nil {
		return fmt.Errorf("failed to save first instance: %w", err)
	}

	// Copy tags to instance
	for _, tag := range template.Tags {
		if err := instance.AddTag(tag); err != nil {
			return fmt.Errorf("failed to add tag to instance: %w", err)
		}
	}

	fmt.Printf("Created recurring task %s\n", template.UUID)
	fmt.Printf("First instance: %s\n", instance.UUID)
	fmt.Printf("Recurrence: %s\n", engine.FormatRecurrenceDuration(duration))

	return nil
}