package client

import (
	"context"
	"fmt"
	"log/slog"
	"time"

	"git.franklin.lab/steve.cliff/pcli/model"
)

func (c *Client) ExportProject(ctx context.Context, projectID string, boardFilter string) (*model.ExportEnvelope, error) {
	// Fetch users for comment attribution
	userMap, err := c.buildUserMap(ctx)
	if err != nil {
		c.Logger.Warn("Failed to fetch users for comment attribution, will use 'unknown user'",
			slog.String("error", err.Error()),
		)
		userMap = make(map[string]string)
	}

	// Get project details
	project, err := c.GetProject(ctx, projectID)
	if err != nil {
		return nil, fmt.Errorf("failed to get project: %w", err)
	}

	// Get all boards for the project
	boards, err := c.ListBoards(ctx)
	if err != nil {
		return nil, fmt.Errorf("failed to list boards: %w", err)
	}

	// Filter boards to this project
	var projectBoards []model.Board
	for _, b := range boards {
		if b.ProjectID == projectID {
			projectBoards = append(projectBoards, b)
		}
	}

	// Apply board filter if specified
	if boardFilter != "" {
		var filtered []model.Board
		for _, b := range projectBoards {
			if b.ID == boardFilter || b.Name == boardFilter {
				filtered = append(filtered, b)
			}
		}
		if len(filtered) == 0 {
			return nil, fmt.Errorf("board %q not found in project %q", boardFilter, project.Name)
		}
		projectBoards = filtered
	}

	// Export each board
	var exportBoards []model.ExportBoard
	for _, b := range projectBoards {
		c.Logger.Info("Exporting board", slog.String("board", b.Name))

		eb, err := c.exportBoard(ctx, b.ID, userMap)
		if err != nil {
			return nil, fmt.Errorf("failed to export board %q: %w", b.Name, err)
		}
		exportBoards = append(exportBoards, *eb)
	}

	return &model.ExportEnvelope{
		Version:    1,
		ExportedAt: time.Now().UTC().Format(time.RFC3339),
		Project: model.ExportProject{
			Name:        project.Name,
			Description: project.Description,
			Boards:      exportBoards,
		},
	}, nil
}

func (c *Client) buildUserMap(ctx context.Context) (map[string]string, error) {
	users, err := c.ListUsers(ctx)
	if err != nil {
		return nil, err
	}

	userMap := make(map[string]string, len(users))
	for _, u := range users {
		userMap[u.ID] = u.Name
	}
	return userMap, nil
}

func (c *Client) exportBoard(ctx context.Context, boardID string, userMap map[string]string) (*model.ExportBoard, error) {
	board, err := c.GetBoard(ctx, boardID)
	if err != nil {
		return nil, err
	}

	// Build lookup maps from board included data
	listMap := make(map[string]string) // id -> name
	systemListIDs := make(map[string]bool)
	for _, l := range board.Lists {
		if l.Type == "archive" || l.Type == "trash" {
			systemListIDs[l.ID] = true
			continue
		}
		name := ""
		if l.Name != nil {
			name = *l.Name
		}
		listMap[l.ID] = name
	}

	labelMap := make(map[string]string) // id -> name
	for _, l := range board.Labels {
		name := ""
		if l.Name != nil {
			name = *l.Name
		}
		labelMap[l.ID] = name
	}

	// Build card -> label names map
	cardLabels := make(map[string][]string)
	for _, cl := range board.CardLabels {
		if name, ok := labelMap[cl.LabelID]; ok {
			cardLabels[cl.CardID] = append(cardLabels[cl.CardID], name)
		}
	}

	// Export lists (skip system lists like archive and trash)
	var exportLists []model.ExportList
	for _, l := range board.Lists {
		if l.Type == "archive" || l.Type == "trash" {
			continue
		}
		name := ""
		if l.Name != nil {
			name = *l.Name
		}
		pos := float64(0)
		if l.Position != nil {
			pos = *l.Position
		}
		exportLists = append(exportLists, model.ExportList{
			Name:     name,
			Position: pos,
			Type:     l.Type,
			Color:    l.Color,
		})
	}

	// Export labels
	var exportLabels []model.ExportLabel
	for _, l := range board.Labels {
		exportLabels = append(exportLabels, model.ExportLabel{
			Name:     l.Name,
			Position: l.Position,
			Color:    l.Color,
		})
	}

	// Export cards with per-card details (skip cards in archive/trash lists)
	var exportCards []model.ExportCard
	for _, card := range board.Cards {
		if systemListIDs[card.ListID] {
			continue
		}
		c.Logger.Debug("Exporting card", slog.String("card", card.Name))

		ec, err := c.exportCard(ctx, card, listMap[card.ListID], cardLabels[card.ID], userMap)
		if err != nil {
			return nil, fmt.Errorf("failed to export card %q: %w", card.Name, err)
		}
		exportCards = append(exportCards, *ec)
	}

	return &model.ExportBoard{
		Name:     board.Name,
		Position: board.Position,
		Lists:    exportLists,
		Labels:   exportLabels,
		Cards:    exportCards,
	}, nil
}

func (c *Client) exportCard(ctx context.Context, card model.Card, listName string, labelNames []string, userMap map[string]string) (*model.ExportCard, error) {
	// Fetch card details (task lists + tasks)
	detail, err := c.GetCard(ctx, card.ID)
	if err != nil {
		return nil, fmt.Errorf("failed to get card details: %w", err)
	}

	// Fetch comments
	comments, err := c.ListComments(ctx, card.ID, 0)
	if err != nil {
		return nil, fmt.Errorf("failed to get card comments: %w", err)
	}

	// Build task list ID -> tasks map
	tasksByList := make(map[string][]model.Task)
	for _, t := range detail.Tasks {
		tasksByList[t.TaskListID] = append(tasksByList[t.TaskListID], t)
	}

	// Export task lists
	var exportTaskLists []model.ExportTaskList
	for _, tl := range detail.TaskLists {
		var exportTasks []model.ExportTask
		for _, t := range tasksByList[tl.ID] {
			exportTasks = append(exportTasks, model.ExportTask{
				Name:        t.Name,
				Position:    t.Position,
				IsCompleted: t.IsCompleted,
			})
		}
		exportTaskLists = append(exportTaskLists, model.ExportTaskList{
			Name:     tl.Name,
			Position: tl.Position,
			Tasks:    exportTasks,
		})
	}

	// Export comments with attribution
	var exportComments []model.ExportComment
	for _, cm := range comments {
		author := "unknown user"
		if cm.UserID != nil {
			if name, ok := userMap[*cm.UserID]; ok {
				author = name
			}
		}
		exportComments = append(exportComments, model.ExportComment{
			Text: fmt.Sprintf("(Original comment by %s)\n%s", author, cm.Text),
		})
	}

	return &model.ExportCard{
		Name:        card.Name,
		Position:    card.Position,
		ListName:    listName,
		LabelNames:  labelNames,
		Description: card.Description,
		DueDate:     card.DueDate,
		IsClosed:    card.IsClosed,
		Type:        card.Type,
		TaskLists:   exportTaskLists,
		Comments:    exportComments,
	}, nil
}