package actions

import (
	"context"
	"database/sql"
	"errors"
	"fmt"

	"git.tjp.lol/punchcard/internal/queries"
)

// PunchIn starts a timer for the specified client/project
// Use empty strings for client/project to use most recent entry
func (a *actions) PunchIn(ctx context.Context, client, project, description string, billableRate *float64, autoUnarchive bool) (*TimerSession, error) {
	// If no client specified, delegate to PunchInMostRecent
	if client == "" && project == "" {
		session, err := a.PunchInMostRecent(ctx, description, billableRate, autoUnarchive)
		if err != nil {
			// Convert "no recent entries" error to "client required" for better UX
			if errors.Is(err, ErrNoRecentEntries) {
				return nil, ErrClientRequired
			}
			return nil, err
		}
		return session, nil
	}

	// Check if there's already an active timer
	activeEntry, err := a.queries.GetActiveTimeEntry(ctx)
	var hasActiveTimer bool
	if err != nil && !errors.Is(err, sql.ErrNoRows) {
		return nil, fmt.Errorf("failed to check for active timer: %w", err)
	}
	hasActiveTimer = (err == nil)

	// Resolve project first (if provided) to get its client
	var projectID sql.NullInt64
	var resolvedProject *queries.Project
	if project != "" {
		proj, err := a.FindProject(ctx, project)
		if err != nil {
			return nil, fmt.Errorf("invalid project: %w", err)
		}
		resolvedProject = proj
		projectID = sql.NullInt64{Int64: proj.ID, Valid: true}
	}

	// Resolve client
	var clientID int64
	var resolvedClient *queries.Client
	if client != "" {
		c, err := a.FindClient(ctx, client)
		if err != nil {
			return nil, fmt.Errorf("invalid client: %w", err)
		}
		resolvedClient = c
		clientID = c.ID

		// Verify project belongs to client if both specified
		if resolvedProject != nil && resolvedProject.ClientID != clientID {
			return nil, fmt.Errorf("%w: project %q does not belong to client %q",
				ErrProjectClientMismatch, project, client)
		}
	} else if resolvedProject != nil {
		// Use project's client
		clientID = resolvedProject.ClientID
		c, err := a.FindClient(ctx, fmt.Sprintf("%d", clientID))
		if err != nil {
			return nil, fmt.Errorf("failed to get client for project: %w", err)
		}
		resolvedClient = c
	} else {
		return nil, ErrClientRequired
	}

	// Check if client is archived
	if resolvedClient.Archived != 0 {
		if !autoUnarchive {
			return nil, ErrArchivedClient
		}
		// Auto-unarchive the client
		if err := a.UnarchiveClient(ctx, resolvedClient.ID); err != nil {
			return nil, fmt.Errorf("failed to unarchive client: %w", err)
		}
	}

	// Check if project is archived
	if resolvedProject != nil && resolvedProject.Archived != 0 {
		if !autoUnarchive {
			return nil, ErrArchivedProject
		}
		// Auto-unarchive the project
		if err := a.UnarchiveProject(ctx, resolvedProject.ID); err != nil {
			return nil, fmt.Errorf("failed to unarchive project: %w", err)
		}
	}

	var stoppedEntryID *int64

	// Check for identical timer if one is active
	if hasActiveTimer {
		if timeEntriesMatch(clientID, projectID, description, billableRate, activeEntry) {
			// No-op: identical timer already active
			return &TimerSession{
				ID:          activeEntry.ID,
				ClientName:  resolvedClient.Name,
				ProjectName: getProjectName(resolvedProject),
				Description: description,
				StartTime:   activeEntry.StartTime,
				EndTime:     nil,
				Duration:    0,
				WasNoOp:     true,
			}, nil
		}

		// Stop the active timer before starting new one
		stoppedEntry, err := a.queries.StopTimeEntry(ctx)
		if err != nil {
			return nil, fmt.Errorf("failed to stop active timer: %w", err)
		}
		stoppedEntryID = &stoppedEntry.ID
	}

	// Create the time entry
	timeEntry, err := a.createTimeEntry(ctx, clientID, projectID, description, billableRate)
	if err != nil {
		return nil, err
	}

	return &TimerSession{
		ID:             timeEntry.ID,
		ClientName:     resolvedClient.Name,
		ProjectName:    getProjectName(resolvedProject),
		Description:    description,
		StartTime:      timeEntry.StartTime,
		EndTime:        nil,
		Duration:       0,
		WasNoOp:        false,
		StoppedEntryID: stoppedEntryID,
	}, nil
}

// PunchInMostRecent starts a timer copying the most recent time entry
func (a *actions) PunchInMostRecent(ctx context.Context, description string, billableRate *float64, autoUnarchive bool) (*TimerSession, error) {
	// Get most recent entry
	mostRecent, err := a.queries.GetMostRecentTimeEntry(ctx)
	if err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return nil, ErrNoRecentEntries
		}
		return nil, fmt.Errorf("failed to get most recent entry: %w", err)
	}

	// Use description from recent entry if none provided
	finalDescription := description
	if finalDescription == "" && mostRecent.Description.Valid {
		finalDescription = mostRecent.Description.String
	}

	// Get client to check if archived
	client, err := a.FindClient(ctx, fmt.Sprintf("%d", mostRecent.ClientID))
	if err != nil {
		return nil, fmt.Errorf("failed to get client: %w", err)
	}

	// Check if client is archived
	if client.Archived != 0 {
		if !autoUnarchive {
			return nil, ErrArchivedClient
		}
		// Auto-unarchive the client
		if err := a.UnarchiveClient(ctx, client.ID); err != nil {
			return nil, fmt.Errorf("failed to unarchive client: %w", err)
		}
	}

	// Check if project is archived (if exists)
	if mostRecent.ProjectID.Valid {
		project, err := a.FindProject(ctx, fmt.Sprintf("%d", mostRecent.ProjectID.Int64))
		if err == nil && project.Archived != 0 {
			if !autoUnarchive {
				return nil, ErrArchivedProject
			}
			// Auto-unarchive the project
			if err := a.UnarchiveProject(ctx, project.ID); err != nil {
				return nil, fmt.Errorf("failed to unarchive project: %w", err)
			}
		}
	}

	// Check if there's already an active timer
	activeEntry, err := a.queries.GetActiveTimeEntry(ctx)
	var hasActiveTimer bool
	if err != nil && !errors.Is(err, sql.ErrNoRows) {
		return nil, fmt.Errorf("failed to check for active timer: %w", err)
	}
	hasActiveTimer = (err == nil)

	var stoppedEntryID *int64

	// Check for identical timer if one is active
	if hasActiveTimer {
		if timeEntriesMatch(mostRecent.ClientID, mostRecent.ProjectID, finalDescription, billableRate, activeEntry) {
			var projectName string
			if mostRecent.ProjectID.Valid {
				project, _ := a.FindProject(ctx, fmt.Sprintf("%d", mostRecent.ProjectID.Int64))
				if project != nil {
					projectName = project.Name
				}
			}

			// No-op: identical timer already active
			return &TimerSession{
				ID:          activeEntry.ID,
				ClientName:  client.Name,
				ProjectName: projectName,
				Description: finalDescription,
				StartTime:   activeEntry.StartTime,
				EndTime:     nil,
				Duration:    0,
				WasNoOp:     true,
			}, nil
		}

		// Stop the active timer before starting new one
		stoppedEntry, err := a.queries.StopTimeEntry(ctx)
		if err != nil {
			return nil, fmt.Errorf("failed to stop active timer: %w", err)
		}
		stoppedEntryID = &stoppedEntry.ID
	}

	// Create new entry copying from most recent
	timeEntry, err := a.createTimeEntry(ctx, mostRecent.ClientID, mostRecent.ProjectID, finalDescription, billableRate)
	if err != nil {
		return nil, err
	}

	// Get project name if exists
	var projectName string
	if mostRecent.ProjectID.Valid {
		project, err := a.FindProject(ctx, fmt.Sprintf("%d", mostRecent.ProjectID.Int64))
		if err == nil {
			projectName = project.Name
		}
	}

	return &TimerSession{
		ID:             timeEntry.ID,
		ClientName:     client.Name,
		ProjectName:    projectName,
		Description:    finalDescription,
		StartTime:      timeEntry.StartTime,
		EndTime:        nil,
		Duration:       0,
		WasNoOp:        false,
		StoppedEntryID: stoppedEntryID,
	}, nil
}

// PunchOut stops the active timer
func (a *actions) PunchOut(ctx context.Context) (*TimerSession, error) {
	stoppedEntry, err := a.queries.StopTimeEntry(ctx)
	if err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return nil, ErrNoActiveTimer
		}
		return nil, fmt.Errorf("failed to stop timer: %w", err)
	}

	duration := stoppedEntry.EndTime.Time.Sub(stoppedEntry.StartTime)
	endTime := stoppedEntry.EndTime.Time

	// Get client name
	client, err := a.FindClient(ctx, fmt.Sprintf("%d", stoppedEntry.ClientID))
	if err != nil {
		return nil, fmt.Errorf("failed to get client name: %w", err)
	}

	// Get project name if exists
	var projectName string
	if stoppedEntry.ProjectID.Valid {
		project, err := a.FindProject(ctx, fmt.Sprintf("%d", stoppedEntry.ProjectID.Int64))
		if err == nil {
			projectName = project.Name
		}
	}

	description := ""
	if stoppedEntry.Description.Valid {
		description = stoppedEntry.Description.String
	}

	return &TimerSession{
		ID:          stoppedEntry.ID,
		ClientName:  client.Name,
		ProjectName: projectName,
		Description: description,
		StartTime:   stoppedEntry.StartTime,
		EndTime:     &endTime,
		Duration:    duration,
	}, nil
}

func (a *actions) EditEntry(ctx context.Context, entry queries.TimeEntry) error {
	return a.queries.EditTimeEntry(ctx, queries.EditTimeEntryParams{
		StartTime:   entry.StartTime,
		EndTime:     entry.EndTime,
		Description: entry.Description,
		ClientID:    entry.ClientID,
		ProjectID:   entry.ProjectID,
		HourlyRate:  entry.BillableRate,
		EntryID:     entry.ID,
	})
}

// Helper functions

func (a *actions) createTimeEntry(ctx context.Context, clientID int64, projectID sql.NullInt64, description string, billableRate *float64) (*queries.TimeEntry, error) {
	var descParam sql.NullString
	if description != "" {
		descParam = sql.NullString{String: description, Valid: true}
	}

	var billableRateParam sql.NullInt64
	if billableRate != nil && *billableRate > 0 {
		rate := int64(*billableRate * 100) // Convert dollars to cents
		billableRateParam = sql.NullInt64{Int64: rate, Valid: true}
	}

	timeEntry, err := a.queries.CreateTimeEntry(ctx, queries.CreateTimeEntryParams{
		Description:  descParam,
		ClientID:     clientID,
		ProjectID:    projectID,
		BillableRate: billableRateParam,
	})
	if err != nil {
		return nil, err
	}
	return &timeEntry, nil
}

func getProjectName(project *queries.Project) string {
	if project == nil {
		return ""
	}
	return project.Name
}

// timeEntriesMatch checks if a new time entry would be identical to an active one
// by comparing client ID, project ID, description, and billable rate
func timeEntriesMatch(clientID int64, projectID sql.NullInt64, description string, billableRate *float64, activeEntry queries.TimeEntry) bool {
	// Client must match
	if activeEntry.ClientID != clientID {
		return false
	}

	// Check project ID matching
	if projectID.Valid != activeEntry.ProjectID.Valid {
		// One has a project, the other doesn't
		return false
	}
	if projectID.Valid {
		// Both have projects - compare IDs
		if activeEntry.ProjectID.Int64 != projectID.Int64 {
			return false
		}
	}

	// Check description matching
	if (description != "") != activeEntry.Description.Valid {
		// One has description, the other doesn't
		return false
	}
	if activeEntry.Description.Valid {
		// Both have descriptions - compare strings
		if activeEntry.Description.String != description {
			return false
		}
	}

	// Check billable rate matching
	if billableRate != nil {
		// New entry has explicit rate
		expectedRate := int64(*billableRate * 100) // Convert to cents
		if !activeEntry.BillableRate.Valid || activeEntry.BillableRate.Int64 != expectedRate {
			return false
		}
	}
	// New entry has no explicit rate - for simplicity, we consider them matching
	// regardless of what coalesced rate the active entry might have

	return true
}