package main

import (
	"encoding/json"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"strings"
	"text/tabwriter"

	ops "fn-registry/fn_operations"
	"fn-registry/registry"
)

const opsDBName = "operations.db"

func cmdOps(args []string) {
	if len(args) < 1 {
		printOpsUsage()
		os.Exit(1)
	}

	switch args[0] {
	case "init":
		cmdOpsInit(args[1:])
	case "entity":
		cmdOpsEntity(args[1:])
	case "relation":
		cmdOpsRelation(args[1:])
	case "graph":
		cmdOpsGraph()
	case "snapshot":
		cmdOpsSnapshot(args[1:])
	case "help", "-h", "--help":
		printOpsUsage()
	default:
		fmt.Fprintf(os.Stderr, "unknown ops command: %s\n", args[0])
		printOpsUsage()
		os.Exit(1)
	}
}

func printOpsUsage() {
	fmt.Println(`fn ops — operations CLI

Usage:
  fn ops init [path]                         Crea operations.db en path (default: .)
  fn ops entity add <flags>                  Añade entity
  fn ops entity list [-d domain] [-s status] Lista entities
  fn ops entity show <id>                    Muestra entity
  fn ops entity delete <id>                  Elimina entity
  fn ops relation add <flags>                Añade relation
  fn ops relation list [entity_id]           Lista relations
  fn ops relation show <id>                  Muestra relation
  fn ops relation delete <id>                Elimina relation
  fn ops graph                               Grafo ASCII de entities y relations
  fn ops snapshot list                       Lista tipos snapshotted

Entity flags:
  --id <id> --name <name> --type-ref <type_id> --source <source>
  --domain <domain> --status <status> --description <desc>
  --tags <t1,t2> --metadata <json> --notes <text>

Relation flags:
  --id <id> --name <name> --from <entity_id> --to <entity_id>
  --via <function_id> --direction <uni|bi|inverse> --status <status>
  --purity <pure|impure> --weight <0.0-1.0> --description <desc>
  --tags <t1,t2> --notes <text>`)
}

// --- ops init ---

func cmdOpsInit(args []string) {
	dir := "."
	if len(args) > 0 {
		dir = args[0]
	}

	path := filepath.Join(dir, opsDBName)
	if _, err := os.Stat(path); err == nil {
		fmt.Fprintf(os.Stderr, "operations.db already exists at %s\n", path)
		os.Exit(1)
	}

	// Copy from template if available, otherwise create fresh
	templatePath := filepath.Join(root(), "fn_operations", "project_template", "operations.db")
	if _, err := os.Stat(templatePath); err == nil {
		src, err := os.Open(templatePath)
		if err != nil {
			fmt.Fprintf(os.Stderr, "error opening template: %v\n", err)
			os.Exit(1)
		}
		defer src.Close()

		if err := os.MkdirAll(dir, 0o755); err != nil {
			fmt.Fprintf(os.Stderr, "error creating directory: %v\n", err)
			os.Exit(1)
		}

		dst, err := os.Create(path)
		if err != nil {
			fmt.Fprintf(os.Stderr, "error creating db: %v\n", err)
			os.Exit(1)
		}
		defer dst.Close()

		if _, err := io.Copy(dst, src); err != nil {
			fmt.Fprintf(os.Stderr, "error copying template: %v\n", err)
			os.Exit(1)
		}
		fmt.Printf("operations.db created at %s (from template)\n", path)
		return
	}

	// Create fresh
	db, err := ops.Open(path)
	if err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(1)
	}
	db.Close()
	fmt.Printf("operations.db created at %s\n", path)
}

// --- ops entity ---

func cmdOpsEntity(args []string) {
	if len(args) < 1 {
		fmt.Fprintln(os.Stderr, "usage: fn ops entity <add|list|show|delete> ...")
		os.Exit(1)
	}

	switch args[0] {
	case "add":
		cmdOpsEntityAdd(args[1:])
	case "list":
		cmdOpsEntityList(args[1:])
	case "show":
		cmdOpsEntityShow(args[1:])
	case "delete":
		cmdOpsEntityDelete(args[1:])
	default:
		fmt.Fprintf(os.Stderr, "unknown entity command: %s\n", args[0])
		os.Exit(1)
	}
}

func cmdOpsEntityAdd(args []string) {
	var e ops.Entity
	e.Status = ops.StatusActive
	var tagsStr, metadataStr string

	for i := 0; i < len(args); i++ {
		switch args[i] {
		case "--id":
			i++; e.ID = args[i]
		case "--name":
			i++; e.Name = args[i]
		case "--type-ref":
			i++; e.TypeRef = args[i]
		case "--source":
			i++; e.Source = args[i]
		case "--domain":
			i++; e.Domain = args[i]
		case "--status":
			i++; e.Status = ops.EntityStatus(args[i])
		case "--description":
			i++; e.Description = args[i]
		case "--tags":
			i++; tagsStr = args[i]
		case "--metadata":
			i++; metadataStr = args[i]
		case "--notes":
			i++; e.Notes = args[i]
		}
	}

	if e.Name == "" || e.TypeRef == "" || e.Source == "" {
		fmt.Fprintln(os.Stderr, "required: --name, --type-ref, --source")
		os.Exit(1)
	}
	if e.ID == "" {
		e.ID = e.Name
	}

	if tagsStr != "" {
		e.Tags = strings.Split(tagsStr, ",")
	}
	if metadataStr != "" {
		json.Unmarshal([]byte(metadataStr), &e.Metadata)
	}

	opsDB := openOpsDB()
	defer opsDB.Close()

	// Try to open registry for type snapshot
	regDB := tryOpenRegistryDB()
	if regDB != nil {
		defer regDB.Close()
	}

	if err := ops.InsertEntityWithSnapshot(opsDB, regDB, &e); err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(1)
	}
	fmt.Printf("Entity %s added\n", e.ID)
}

func cmdOpsEntityList(args []string) {
	var domain string
	var status ops.EntityStatus
	for i := 0; i < len(args); i++ {
		switch args[i] {
		case "-d":
			i++; domain = args[i]
		case "-s":
			i++; status = ops.EntityStatus(args[i])
		}
	}

	db := openOpsDB()
	defer db.Close()

	entities, err := db.ListEntities(domain, status)
	if err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(1)
	}

	if len(entities) == 0 {
		fmt.Println("No entities.")
		return
	}

	w := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0)
	fmt.Fprintln(w, "ID\tTYPE_REF\tSTATUS\tSOURCE\tDOMAIN")
	for _, e := range entities {
		fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\n", e.ID, e.TypeRef, e.Status, e.Source, e.Domain)
	}
	w.Flush()
}

func cmdOpsEntityShow(args []string) {
	if len(args) < 1 {
		fmt.Fprintln(os.Stderr, "usage: fn ops entity show <id>")
		os.Exit(1)
	}

	db := openOpsDB()
	defer db.Close()

	e, err := db.GetEntity(args[0])
	if err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(1)
	}
	if e == nil {
		fmt.Fprintf(os.Stderr, "entity not found: %s\n", args[0])
		os.Exit(1)
	}

	fmt.Printf("ID:          %s\n", e.ID)
	fmt.Printf("Name:        %s\n", e.Name)
	fmt.Printf("Type ref:    %s\n", e.TypeRef)
	fmt.Printf("Status:      %s\n", e.Status)
	fmt.Printf("Source:      %s\n", e.Source)
	fmt.Printf("Domain:      %s\n", e.Domain)
	fmt.Printf("Description: %s\n", e.Description)
	fmt.Printf("Tags:        %s\n", strings.Join(e.Tags, ", "))
	if len(e.Metadata) > 0 {
		meta, _ := json.MarshalIndent(e.Metadata, "             ", "  ")
		fmt.Printf("Metadata:    %s\n", meta)
	}
	if e.Notes != "" {
		fmt.Printf("Notes:       %s\n", e.Notes)
	}
	fmt.Printf("Created:     %s\n", e.CreatedAt.Format("2006-01-02 15:04:05"))
	fmt.Printf("Updated:     %s\n", e.UpdatedAt.Format("2006-01-02 15:04:05"))
}

func cmdOpsEntityDelete(args []string) {
	if len(args) < 1 {
		fmt.Fprintln(os.Stderr, "usage: fn ops entity delete <id>")
		os.Exit(1)
	}

	db := openOpsDB()
	defer db.Close()

	if err := db.DeleteEntity(args[0]); err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(1)
	}
	fmt.Printf("Entity %s deleted\n", args[0])
}

// --- ops relation ---

func cmdOpsRelation(args []string) {
	if len(args) < 1 {
		fmt.Fprintln(os.Stderr, "usage: fn ops relation <add|list|show|delete> ...")
		os.Exit(1)
	}

	switch args[0] {
	case "add":
		cmdOpsRelationAdd(args[1:])
	case "list":
		cmdOpsRelationList(args[1:])
	case "show":
		cmdOpsRelationShow(args[1:])
	case "delete":
		cmdOpsRelationDelete(args[1:])
	default:
		fmt.Fprintf(os.Stderr, "unknown relation command: %s\n", args[0])
		os.Exit(1)
	}
}

func cmdOpsRelationAdd(args []string) {
	var r ops.Relation
	r.Direction = ops.DirUnidirectional
	r.Status = ops.RelDesigned
	var tagsStr string

	for i := 0; i < len(args); i++ {
		switch args[i] {
		case "--id":
			i++; r.ID = args[i]
		case "--name":
			i++; r.Name = args[i]
		case "--from":
			i++; r.FromEntity = args[i]
		case "--to":
			i++; r.ToEntity = args[i]
		case "--via":
			i++; r.Via = args[i]
		case "--direction":
			i++; r.Direction = ops.Direction(args[i])
		case "--status":
			i++; r.Status = ops.RelationStatus(args[i])
		case "--purity":
			i++; r.Purity = args[i]
		case "--weight":
			i++
			var w float64
			fmt.Sscanf(args[i], "%f", &w)
			r.Weight = &w
		case "--description":
			i++; r.Description = args[i]
		case "--tags":
			i++; tagsStr = args[i]
		case "--notes":
			i++; r.Notes = args[i]
		}
	}

	if r.Name == "" || r.ToEntity == "" {
		fmt.Fprintln(os.Stderr, "required: --name, --to (and --from for simple relations)")
		os.Exit(1)
	}
	if r.ID == "" && r.FromEntity != "" {
		via := "semantic"
		if r.Via != "" {
			via = r.Via
		}
		r.ID = fmt.Sprintf("%s__to__%s__via__%s", r.FromEntity, r.ToEntity, via)
	}
	if tagsStr != "" {
		r.Tags = strings.Split(tagsStr, ",")
	}

	db := openOpsDB()
	defer db.Close()

	if err := ops.InsertRelationSafe(db, &r); err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(1)
	}
	fmt.Printf("Relation %s added\n", r.ID)
}

func cmdOpsRelationList(args []string) {
	var entityID string
	if len(args) > 0 {
		entityID = args[0]
	}

	db := openOpsDB()
	defer db.Close()

	rels, err := db.ListRelations(entityID)
	if err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(1)
	}

	if len(rels) == 0 {
		fmt.Println("No relations.")
		return
	}

	w := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0)
	fmt.Fprintln(w, "ID\tNAME\tFROM\tTO\tVIA\tDIRECTION\tSTATUS")
	for _, r := range rels {
		from := r.FromEntity
		if from == "" {
			from = "(inputs)"
		}
		via := r.Via
		if via == "" {
			via = "-"
		}
		fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\t%s\t%s\n",
			r.ID, r.Name, from, r.ToEntity, via, r.Direction, r.Status)
	}
	w.Flush()
}

func cmdOpsRelationShow(args []string) {
	if len(args) < 1 {
		fmt.Fprintln(os.Stderr, "usage: fn ops relation show <id>")
		os.Exit(1)
	}

	db := openOpsDB()
	defer db.Close()

	r, err := db.GetRelation(args[0])
	if err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(1)
	}
	if r == nil {
		fmt.Fprintf(os.Stderr, "relation not found: %s\n", args[0])
		os.Exit(1)
	}

	fmt.Printf("ID:          %s\n", r.ID)
	fmt.Printf("Name:        %s\n", r.Name)
	fmt.Printf("From:        %s\n", r.FromEntity)
	fmt.Printf("To:          %s\n", r.ToEntity)
	fmt.Printf("Via:         %s\n", r.Via)
	fmt.Printf("Description: %s\n", r.Description)
	fmt.Printf("Purity:      %s\n", r.Purity)
	fmt.Printf("Direction:   %s\n", r.Direction)
	if r.Weight != nil {
		fmt.Printf("Weight:      %.2f\n", *r.Weight)
	}
	fmt.Printf("Status:      %s\n", r.Status)
	fmt.Printf("Tags:        %s\n", strings.Join(r.Tags, ", "))
	if r.Notes != "" {
		fmt.Printf("Notes:       %s\n", r.Notes)
	}

	// Show inputs if any
	inputs, _ := db.GetRelationInputs(r.ID)
	if len(inputs) > 0 {
		fmt.Println("\nInputs:")
		for _, ri := range inputs {
			ord := ""
			if ri.Order != nil {
				ord = fmt.Sprintf(" (order: %d)", *ri.Order)
			}
			fmt.Printf("  %s [%s]%s\n", ri.EntityID, ri.Role, ord)
		}
	}
}

func cmdOpsRelationDelete(args []string) {
	if len(args) < 1 {
		fmt.Fprintln(os.Stderr, "usage: fn ops relation delete <id>")
		os.Exit(1)
	}

	db := openOpsDB()
	defer db.Close()

	if err := db.DeleteRelation(args[0]); err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(1)
	}
	fmt.Printf("Relation %s deleted\n", args[0])
}

// --- ops graph ---

func cmdOpsGraph() {
	db := openOpsDB()
	defer db.Close()

	g, err := ops.GetEntityGraph(db)
	if err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(1)
	}

	if len(g.Entities) == 0 {
		fmt.Println("Empty graph.")
		return
	}

	fmt.Println("Entities:")
	for _, e := range g.Entities {
		fmt.Printf("  [%s] (%s) status:%s source:%s\n", e.ID, e.TypeRef, e.Status, e.Source)
	}

	if len(g.Relations) > 0 {
		fmt.Println("\nRelations:")
		for _, r := range g.Relations {
			via := ""
			if r.Via != "" {
				via = fmt.Sprintf(" via:%s", r.Via)
			}

			inputs, hasInputs := g.Inputs[r.ID]
			if hasInputs {
				sources := make([]string, len(inputs))
				for i, ri := range inputs {
					sources[i] = fmt.Sprintf("%s[%s]", ri.EntityID, ri.Role)
				}
				fmt.Printf("  (%s) %s → %s%s\n",
					strings.Join(sources, " + "), r.Name, r.ToEntity, via)
			} else {
				from := r.FromEntity
				if from == "" {
					from = "?"
				}
				dir := "→"
				if r.Direction == ops.DirBidirectional {
					dir = "↔"
				}
				fmt.Printf("  %s %s %s %s%s\n", from, dir, r.Name, r.ToEntity, via)
			}
		}
	}
}

// --- ops snapshot ---

func cmdOpsSnapshot(args []string) {
	if len(args) < 1 || args[0] != "list" {
		fmt.Fprintln(os.Stderr, "usage: fn ops snapshot list")
		os.Exit(1)
	}

	db := openOpsDB()
	defer db.Close()

	snaps, err := db.ListTypeSnapshots()
	if err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(1)
	}

	if len(snaps) == 0 {
		fmt.Println("No type snapshots.")
		return
	}

	w := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0)
	fmt.Fprintln(w, "ID\tVERSION\tLANG\tALGEBRAIC\tSNAPPED_AT")
	for _, s := range snaps {
		fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\n",
			s.ID, s.Version, s.Lang, s.Algebraic, s.SnappedAt.Format("2006-01-02 15:04"))
	}
	w.Flush()
}

// --- helpers ---

func findOpsDB() string {
	dir, _ := os.Getwd()
	for {
		path := filepath.Join(dir, opsDBName)
		if _, err := os.Stat(path); err == nil {
			return path
		}
		parent := filepath.Dir(dir)
		if parent == dir {
			break
		}
		dir = parent
	}
	return filepath.Join(".", opsDBName)
}

func openOpsDB() *ops.DB {
	path := findOpsDB()
	db, err := ops.Open(path)
	if err != nil {
		fmt.Fprintf(os.Stderr, "error opening operations.db: %v\n", err)
		fmt.Fprintln(os.Stderr, "Run 'fn ops init' first to create one.")
		os.Exit(1)
	}
	return db
}

func tryOpenRegistryDB() *registry.DB {
	// Try FN_REGISTRY_ROOT env var first
	if envRoot := os.Getenv("FN_REGISTRY_ROOT"); envRoot != "" {
		path := filepath.Join(envRoot, dbName)
		if _, err := os.Stat(path); err == nil {
			db, err := registry.Open(path)
			if err == nil {
				return db
			}
		}
	}

	// Try root() (finds go.mod walking up from cwd)
	path := filepath.Join(root(), dbName)
	if _, err := os.Stat(path); err == nil {
		db, err := registry.Open(path)
		if err == nil {
			return db
		}
	}

	// Try executable's directory
	if exe, err := os.Executable(); err == nil {
		exeDir := filepath.Dir(exe)
		path := filepath.Join(exeDir, dbName)
		if _, err := os.Stat(path); err == nil {
			db, err := registry.Open(path)
			if err == nil {
				return db
			}
		}
	}

	return nil
}