package cmd

import (
	"encoding/json"
	"fmt"
	"os"
	"strings"

	"github.com/david/knox/internal/db"
	"github.com/david/knox/internal/index"
	"github.com/spf13/cobra"
)

func paginate(entries []db.Entry, page, limit int) []db.Entry {
	start := (page - 1) * limit
	if start >= len(entries) {
		return nil
	}
	end := start + limit
	if end > len(entries) {
		end = len(entries)
	}
	return entries[start:end]
}

func NewStatusCmd(kdb *db.KnoxDB) *cobra.Command {
	var jsonOut bool
	cmd := &cobra.Command{
		Use:   "status",
		Short: "Show knowledge index statistics",
		RunE: func(c *cobra.Command, args []string) error {
			stats, err := kdb.Stats()
			if err != nil {
				return err
			}
			if jsonOut {
				b, _ := json.MarshalIndent(stats, "", "  ")
				fmt.Println(string(b))
				return nil
			}
			fmt.Println("Knox Knowledge Index")
			fmt.Println("====================")
			for k, v := range stats {
				switch val := v.(type) {
				case int:
					fmt.Printf("  %-24s %d\n", k+":", val)
				case string:
					fmt.Printf("  %-24s %s\n", k+":", val)
				default:
					fmt.Printf("  %-24s %v\n", k+":", val)
				}
			}
			return nil
		},
	}
	cmd.Flags().BoolVar(&jsonOut, "json", false, "Output as JSON")
	return cmd
}

func NewQueryCmd(kdb *db.KnoxDB) *cobra.Command {
	var page, limit int
	cmd := &cobra.Command{
		Use:   "query [search text]",
		Short: "Search the knowledge index",
		Long:  "Search the knowledge index. Reads from stdin pipe if no positional arg given.",
		RunE: func(c *cobra.Command, args []string) error {
			query := ""
			if len(args) > 0 {
				query = args[0]
			} else {
				stdin, _ := os.ReadFile(os.Stdin.Name())
				query = strings.TrimSpace(string(stdin))
			}
			if query == "" {
				return fmt.Errorf("search query required (positional arg or stdin pipe)")
			}
			results, err := kdb.Search(query, limit)
			if err != nil {
				return err
			}
			results = paginate(results, page, limit)
			if len(results) == 0 {
				fmt.Println("No results found.")
				return nil
			}
			fmt.Printf("Found %d results for %q (page %d, %d per page):\n\n", len(results), query, page, limit)
			for _, r := range results {
				fmt.Printf("  %-8s %-30s [%s] %s\n", shortFP(r.Fingerprint), truncateStr(r.Title, 30), r.Project, r.SourceID)
				if r.Summary != "" {
					fmt.Printf("  %-8s %s\n", "", truncateStr(r.Summary, 80))
				}
				fmt.Println()
			}
			return nil
		},
	}
	cmd.Flags().IntVarP(&page, "page", "p", 1, "Page number (1-based)")
	cmd.Flags().IntVarP(&limit, "limit", "l", 20, "Results per page")
	return cmd
}

func NewRecentCmd(kdb *db.KnoxDB) *cobra.Command {
	var page, limit int
	cmd := &cobra.Command{
		Use:   "recent",
		Short: "Show recent knowledge entries",
		RunE: func(c *cobra.Command, args []string) error {
			all, err := kdb.RecentEntries(limit * 10)
			if err != nil {
				return err
			}
			entries := paginate(all, page, limit)
			if len(entries) == 0 {
				fmt.Println("No entries yet. Run `knox watch` to start ingesting.")
				return nil
			}
			fmt.Printf("Recent %d entries (page %d, %d per page):\n\n", len(entries), page, limit)
			for _, e := range entries {
				fmt.Printf("  %-8s %-30s [%s] %s\n", shortFP(e.Fingerprint), truncateStr(e.Title, 30), e.Project, e.SourceID)
			}
			return nil
		},
	}
	cmd.Flags().IntVarP(&page, "page", "p", 1, "Page number (1-based)")
	cmd.Flags().IntVarP(&limit, "limit", "l", 20, "Results per page")
	return cmd
}

func NewReflectCmd(kdb *db.KnoxDB) *cobra.Command {
	return &cobra.Command{
		Use:   "reflect",
		Short: "Process pending sessions for reflection",
		Long:  "Scans for sessions not yet indexed, runs reflection, and reports findings.",
		RunE: func(c *cobra.Command, args []string) error {
			reflector := index.NewReflector(kdb)
			results, err := reflector.Reflect()
			if err != nil {
				return err
			}
			if len(results) == 0 {
				fmt.Println("All caught up — no pending sessions to reflect on.")
				return nil
			}
			fmt.Printf("Reflected %d sessions:\n\n", len(results))
			fmt.Print(reflector.FormatResult(results))

			gaps, _ := reflector.Gaps()
			if len(gaps) > 0 {
				fmt.Printf("\nProjects with indexed knowledge:\n")
				for _, g := range gaps {
					fmt.Printf("  %-20s %d entries\n", g.Project, g.TotalEntries)
				}
			}
			return nil
		},
	}
}

func getHomeDir() (string, error) {
	return os.UserHomeDir()
}