package main

import (
	"bufio"
	"context"
	"fmt"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"time"

	"fiatjaf.com/nostr"
	"fiatjaf.com/nostr/nip19"
	"fiatjaf.com/nostr/sdk/hints"
	"github.com/fatih/color"
	"github.com/markusmobius/go-dateparser"
	"github.com/urfave/cli/v3"
)

var spell = &cli.Command{
	Name:        "spell",
	Usage:       "downloads a spell event and executes its REQ request",
	ArgsUsage:   "[nevent_code]",
	Description: `fetches a spell event (kind 777) and executes REQ command encoded in its tags.`,
	Flags: append(defaultKeyFlags,
		&cli.UintFlag{
			Name:    "outbox-relays-per-pubkey",
			Aliases: []string{"n"},
			Usage:   "number of outbox relays to use for each pubkey",
			Value:   3,
		},
	),
	Action: func(ctx context.Context, c *cli.Command) error {
		// load history from file
		var history []SpellHistoryEntry
		historyPath, err := getSpellHistoryPath()
		if err == nil {
			file, err := os.Open(historyPath)
			if err == nil {
				defer file.Close()
				scanner := bufio.NewScanner(file)
				for scanner.Scan() {
					var entry SpellHistoryEntry
					if err := json.Unmarshal([]byte(scanner.Text()), &entry); err != nil {
						continue // skip invalid entries
					}
					history = append(history, entry)
				}
			}
		}

		if c.Args().Len() == 0 {
			log("recent spells:\n")
			for i, entry := range history {
				if i >= 10 {
					break
				}

				displayName := entry.Name
				if displayName == "" {
					displayName = entry.Content
					if len(displayName) > 28 {
						displayName = displayName[:27] + "…"
					}
				}
				if displayName != "" {
					displayName = displayName + ": "
				}

				desc := entry.Content
				if len(desc) > 50 {
					desc = desc[0:49] + "…"
				}

				lastUsed := entry.LastUsed.Format("2006-01-02 15:04")
				stdout(fmt.Sprintf("  %s %s%s - %s\n",
					color.BlueString(entry.Identifier),
					displayName,
					color.YellowString(lastUsed),
					desc,
				))
			}
			return nil
		}

		// decode nevent to get the spell event
		var pointer nostr.EventPointer
		identifier := c.Args().First()
		prefix, value, err := nip19.Decode(identifier)
		if err == nil {
			if prefix != "nevent" {
				return fmt.Errorf("expected nevent code, got %s", prefix)
			}
			pointer = value.(nostr.EventPointer)
		} else {
			// search our history
			for _, entry := range history {
				if entry.Identifier == identifier {
					pointer = entry.Pointer
					break
				}
			}
		}

		if pointer.ID == nostr.ZeroID {
			return fmt.Errorf("invalid spell reference")
		}

		// fetch spell
		relays := pointer.Relays
		if pointer.Author != nostr.ZeroPK {
			for _, url := range relays {
				sys.Hints.Save(pointer.Author, nostr.NormalizeURL(url), hints.LastInHint, nostr.Now())
			}
			relays = append(relays, sys.FetchOutboxRelays(ctx, pointer.Author, 3)...)
		}
		spell := sys.Pool.QuerySingle(ctx, relays, nostr.Filter{IDs: []nostr.ID{pointer.ID}},
			nostr.SubscriptionOptions{Label: "nak-spell-f"})
		if spell == nil {
			return fmt.Errorf("spell event not found")
		}
		if spell.Kind != 777 {
			return fmt.Errorf("event is not a spell (expected kind 777, got %d)", spell.Kind)
		}

		// parse spell tags to build REQ filter
		spellFilter, err := buildSpellReq(ctx, c, spell.Tags)
		if err != nil {
			return fmt.Errorf("failed to parse spell tags: %w", err)
		}

		// determine relays to query
		var spellRelays []string
		var outbox bool
		relaysTag := spell.Event.Tags.Find("relays")
		if relaysTag == nil {
			// if this tag doesn't exist assume $outbox
			relaysTag = nostr.Tag{"relays", "$outbox"}
		}
		for i := 1; i < len(relaysTag); i++ {
			switch relaysTag[i] {
			case "$outbox":
				outbox = true
			default:
				relays = append(relays, relaysTag[i])
			}
		}

		stream := !spell.Tags.Has("close-on-eose")

		// fill in the author if we didn't have it
		pointer.Author = spell.PubKey

		// add to history before execution
		{
			idStr := nip19.EncodeNevent(spell.ID, nil, nostr.ZeroPK)
			identifier = "spell" + idStr[len(idStr)-7:]
			nameTag := spell.Tags.Find("name")
			var name string
			if nameTag != nil {
				name = nameTag[1]
			}
			if len(history) > 100 {
				history = history[:100]
			}
			// write back to file
			file, err := os.Create(historyPath)
			if err != nil {
				return err
			}
			data, _ := json.Marshal(SpellHistoryEntry{
				Identifier: identifier,
				Name:       name,
				Content:    spell.Content,
				LastUsed:   time.Now(),
				Pointer:    pointer,
			})
			file.Write(data)
			file.Write([]byte{'\n'})
			for i, entry := range history {
				// limit history size (keep last 100)
				if i == 100 {
					break
				}

				data, _ := json.Marshal(entry)
				file.Write(data)
				file.Write([]byte{'\n'})
			}
			file.Close()

			logverbose("executing %s: %s relays=%v outbox=%v stream=%v\n",
				identifier, spellFilter, spellRelays, outbox, stream)
		}

		// execute
		performReq(ctx, spellFilter, spellRelays, stream, outbox, c.Uint("outbox-relays-per-pubkey"), false, 0, "nak-spell")

		return nil
	},
}

func buildSpellReq(ctx context.Context, c *cli.Command, tags nostr.Tags) (nostr.Filter, error) {
	filter := nostr.Filter{}

	getMe := func() (nostr.PubKey, error) {
		kr, _, err := gatherKeyerFromArguments(ctx, c)
		if err != nil {
			return nostr.ZeroPK, fmt.Errorf("failed to get keyer: %w", err)
		}

		pubkey, err := kr.GetPublicKey(ctx)
		if err != nil {
			return nostr.ZeroPK, fmt.Errorf("failed to get public key from keyer: %w", err)
		}

		return pubkey, nil
	}

	for _, tag := range tags {
		if len(tag) == 0 {
			continue
		}

		switch tag[0] {
		case "cmd":
			if len(tag) < 2 || tag[1] != "REQ" {
				return nostr.Filter{}, fmt.Errorf("only REQ commands are supported")
			}

		case "k":
			for i := 1; i < len(tag); i++ {
				if kind, err := strconv.Atoi(tag[i]); err == nil {
					filter.Kinds = append(filter.Kinds, nostr.Kind(kind))
				}
			}

		case "authors":
			for i := 1; i < len(tag); i++ {
				switch tag[i] {
				case "$me":
					me, err := getMe()
					if err != nil {
						return nostr.Filter{}, err
					}
					filter.Authors = append(filter.Authors, me)
				case "$contacts":
					me, err := getMe()
					if err != nil {
						return nostr.Filter{}, err
					}
					for _, f := range sys.FetchFollowList(ctx, me).Items {
						filter.Authors = append(filter.Authors, f.Pubkey)
					}
				default:
					pubkey, err := nostr.PubKeyFromHex(tag[i])
					if err != nil {
						return nostr.Filter{}, fmt.Errorf("invalid pubkey '%s' in 'authors': %w", tag[i], err)
					}
					filter.Authors = append(filter.Authors, pubkey)
				}
			}

		case "ids":
			for i := 1; i < len(tag); i++ {
				id, err := nostr.IDFromHex(tag[i])
				if err != nil {
					return nostr.Filter{}, fmt.Errorf("invalid  id '%s' in 'authors': %w", tag[i], err)
				}
				filter.IDs = append(filter.IDs, id)
			}

		case "tag":
			if len(tag) < 3 {
				continue
			}
			tagName := tag[1]
			if filter.Tags == nil {
				filter.Tags = make(nostr.TagMap)
			}
			for i := 2; i < len(tag); i++ {
				switch tag[i] {
				case "$me":
					me, err := getMe()
					if err != nil {
						return nostr.Filter{}, err
					}
					filter.Tags[tagName] = append(filter.Tags[tagName], me.Hex())
				case "$contacts":
					me, err := getMe()
					if err != nil {
						return nostr.Filter{}, err
					}
					for _, f := range sys.FetchFollowList(ctx, me).Items {
						filter.Tags[tagName] = append(filter.Tags[tagName], f.Pubkey.Hex())
					}
				default:
					filter.Tags[tagName] = append(filter.Tags[tagName], tag[i])
				}
			}

		case "limit":
			if len(tag) >= 2 {
				if limit, err := strconv.Atoi(tag[1]); err == nil {
					filter.Limit = limit
				}
			}

		case "since":
			if len(tag) >= 2 {
				date, err := dateparser.Parse(&dateparser.Configuration{
					DefaultTimezone: time.Local,
					CurrentTime:     time.Now(),
				}, tag[1])
				if err != nil {
					return nostr.Filter{}, fmt.Errorf("invalid date %s: %w", tag[1], err)
				}
				filter.Since = nostr.Timestamp(date.Time.Unix())
			}

		case "until":
			if len(tag) >= 2 {
				date, err := dateparser.Parse(&dateparser.Configuration{
					DefaultTimezone: time.Local,
					CurrentTime:     time.Now(),
				}, tag[1])
				if err != nil {
					return nostr.Filter{}, fmt.Errorf("invalid date %s: %w", tag[1], err)
				}
				filter.Until = nostr.Timestamp(date.Time.Unix())
			}

		case "search":
			if len(tag) >= 2 {
				filter.Search = tag[1]
			}
		}
	}

	return filter, nil
}

func parseRelativeTime(timeStr string) (nostr.Timestamp, error) {
	// Handle special cases
	switch timeStr {
	case "now":
		return nostr.Now(), nil
	}

	// Try to parse as relative time (e.g., "7d", "1h", "30m")
	if strings.HasSuffix(timeStr, "d") {
		days := strings.TrimSuffix(timeStr, "d")
		if daysInt, err := strconv.Atoi(days); err == nil {
			return nostr.Now() - nostr.Timestamp(daysInt*24*60*60), nil
		}
	} else if strings.HasSuffix(timeStr, "h") {
		hours := strings.TrimSuffix(timeStr, "h")
		if hoursInt, err := strconv.Atoi(hours); err == nil {
			return nostr.Now() - nostr.Timestamp(hoursInt*60*60), nil
		}
	} else if strings.HasSuffix(timeStr, "m") {
		minutes := strings.TrimSuffix(timeStr, "m")
		if minutesInt, err := strconv.Atoi(minutes); err == nil {
			return nostr.Now() - nostr.Timestamp(minutesInt*60), nil
		}
	}

	// try to parse as direct timestamp
	if ts, err := strconv.ParseInt(timeStr, 10, 64); err == nil {
		return nostr.Timestamp(ts), nil
	}

	return 0, fmt.Errorf("invalid time format: %s", timeStr)
}

type SpellHistoryEntry struct {
	Identifier string             `json:"_id"`
	Name       string             `json:"name,omitempty"`
	Content    string             `json:"content,omitempty"`
	LastUsed   time.Time          `json:"last_used"`
	Pointer    nostr.EventPointer `json:"pointer"`
}

func getSpellHistoryPath() (string, error) {
	home, err := os.UserHomeDir()
	if err != nil {
		return "", err
	}
	historyDir := filepath.Join(home, ".config", "nak", "spells")

	// create directory if it doesn't exist
	if err := os.MkdirAll(historyDir, 0755); err != nil {
		return "", err
	}

	return filepath.Join(historyDir, "history"), nil
}