package engine

import (
	"fmt"
	"strings"
	"time"

	"github.com/fatih/color"
)

// FormatTaskList formats a list of tasks for display
func FormatTaskList(tasks []*Task, ws *WorkingSet) string {
	if len(tasks) == 0 {
		return "No tasks found."
	}

	var sb strings.Builder

	// Header
	sb.WriteString(fmt.Sprintf("%-3s %-8s %-3s %-12s %-40s %-12s %s\n",
		"ID", "Status", "Pri", "Project", "Description", "Due", "Tags"))
	sb.WriteString(strings.Repeat("-", 100) + "\n")

	// Tasks
	for i, task := range tasks {
		displayID := i + 1
		if ws != nil {
			// Use working set display ID if available
			for id, uuid := range ws.byID {
				if uuid == task.UUID {
					displayID = id
					break
				}
			}
		}

		status := formatStatus(task.Status)
		priority := formatPriority(task.Priority)
		project := formatProject(task.Project)
		description := truncate(task.Description, 40)
		due := formatDue(task.Due)
		tags := formatTags(task.Tags)

		sb.WriteString(fmt.Sprintf("%-3d %-8s %-3s %-12s %-40s %-12s %s\n",
			displayID, status, priority, project, description, due, tags))
	}

	return sb.String()
}

// FormatTaskDetail formats detailed task information
func FormatTaskDetail(task *Task) string {
	var sb strings.Builder

	sb.WriteString(color.New(color.Bold).Sprint("Task Details") + "\n")
	sb.WriteString(strings.Repeat("=", 50) + "\n")

	sb.WriteString(fmt.Sprintf("UUID:        %s\n", task.UUID))
	sb.WriteString(fmt.Sprintf("Status:      %s\n", formatStatus(task.Status)))
	sb.WriteString(fmt.Sprintf("Description: %s\n", task.Description))
	sb.WriteString(fmt.Sprintf("Priority:    %s\n", formatPriority(task.Priority)))
	sb.WriteString(fmt.Sprintf("Project:     %s\n", formatProject(task.Project)))

	sb.WriteString(fmt.Sprintf("\nCreated:     %s\n", formatTime(task.Created)))
	sb.WriteString(fmt.Sprintf("Modified:    %s\n", formatTime(task.Modified)))

	if task.Start != nil {
		sb.WriteString(fmt.Sprintf("Started:     %s\n", formatTime(*task.Start)))
	}

	if task.End != nil {
		sb.WriteString(fmt.Sprintf("Ended:       %s\n", formatTime(*task.End)))
	}

	if task.Due != nil {
		sb.WriteString(fmt.Sprintf("Due:         %s\n", formatTimeWithColor(*task.Due)))
	}

	if task.Scheduled != nil {
		sb.WriteString(fmt.Sprintf("Scheduled:   %s\n", formatTime(*task.Scheduled)))
	}

	if task.Wait != nil {
		sb.WriteString(fmt.Sprintf("Wait:        %s\n", formatTime(*task.Wait)))
	}

	if task.Until != nil {
		sb.WriteString(fmt.Sprintf("Until:       %s\n", formatTime(*task.Until)))
	}

	if task.RecurrenceDuration != nil {
		sb.WriteString(fmt.Sprintf("Recurrence:  %s\n", FormatRecurrenceDuration(*task.RecurrenceDuration)))
	}

	if task.ParentUUID != nil {
		sb.WriteString(fmt.Sprintf("Parent:      %s (recurring instance)\n", *task.ParentUUID))
	}

	if len(task.Tags) > 0 {
		sb.WriteString(fmt.Sprintf("\nTags:        %s\n", formatTags(task.Tags)))
	}

	return sb.String()
}

// FormatProjects formats project list with counts
func FormatProjects(projectCounts map[string]int) string {
	if len(projectCounts) == 0 {
		return "No projects found."
	}

	var sb strings.Builder
	sb.WriteString(fmt.Sprintf("%-20s %s\n", "Project", "Count"))
	sb.WriteString(strings.Repeat("-", 30) + "\n")

	for project, count := range projectCounts {
		sb.WriteString(fmt.Sprintf("%-20s %d\n", project, count))
	}

	return sb.String()
}

// FormatTags formats tag list with counts
func FormatTagCounts(tagCounts map[string]int) string {
	if len(tagCounts) == 0 {
		return "No tags found."
	}

	var sb strings.Builder
	sb.WriteString(fmt.Sprintf("%-20s %s\n", "Tag", "Count"))
	sb.WriteString(strings.Repeat("-", 30) + "\n")

	for tag, count := range tagCounts {
		sb.WriteString(fmt.Sprintf("%-20s %d\n", tag, count))
	}

	return sb.String()
}

// Helper functions

func formatStatus(status Status) string {
	switch status {
	case StatusPending:
		return color.YellowString("pending")
	case StatusCompleted:
		return color.GreenString("done")
	case StatusDeleted:
		return color.RedString("deleted")
	case StatusRecurring:
		return color.BlueString("template")
	default:
		return "unknown"
	}
}

func formatPriority(priority Priority) string {
	switch priority {
	case PriorityHigh:
		return color.RedString("H")
	case PriorityMedium:
		return color.YellowString("M")
	case PriorityLow:
		return color.CyanString("L")
	case PriorityDefault:
		return "D"
	default:
		return "D"
	}
}

func formatProject(project *string) string {
	if project == nil {
		return "-"
	}
	return *project
}

func formatDue(due *time.Time) string {
	if due == nil {
		return ""
	}

	now := time.Now()
	if due.Before(now) {
		return color.RedString(due.Format("2006-01-02"))
	}

	if due.Before(now.Add(24 * time.Hour)) {
		return color.YellowString(due.Format("2006-01-02"))
	}

	return due.Format("2006-01-02")
}

func formatTimeWithColor(t time.Time) string {
	now := time.Now()
	if t.Before(now) {
		return color.RedString(t.Format("2006-01-02 15:04"))
	}
	return t.Format("2006-01-02 15:04")
}

func formatTime(t time.Time) string {
	return t.Format("2006-01-02 15:04")
}

func formatTags(tags []string) string {
	if len(tags) == 0 {
		return ""
	}

	formatted := make([]string, len(tags))
	for i, tag := range tags {
		formatted[i] = color.CyanString("+" + tag)
	}
	return strings.Join(formatted, " ")
}

func truncate(s string, maxLen int) string {
	if len(s) <= maxLen {
		return s
	}
	return s[:maxLen-3] + "..."
}

// GetProjectCounts returns a map of project names to task counts
func GetProjectCounts() (map[string]int, error) {
	tasks, err := GetTasks(DefaultFilter())
	if err != nil {
		return nil, err
	}

	counts := make(map[string]int)
	for _, task := range tasks {
		if task.Project != nil {
			counts[*task.Project]++
		}
	}

	return counts, nil
}

// GetTagCounts returns a map of tags to task counts
func GetTagCounts() (map[string]int, error) {
	tasks, err := GetTasks(DefaultFilter())
	if err != nil {
		return nil, err
	}

	counts := make(map[string]int)
	for _, task := range tasks {
		for _, tag := range task.Tags {
			counts[tag]++
		}
	}

	return counts, nil
}