package main

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

	"fn-registry/functions/infra"
)

func cmdDoctor(args []string) {
	jsonOut := false
	sub := ""
	for _, a := range args {
		switch a {
		case "--json":
			jsonOut = true
		case "-h", "--help":
			doctorUsage()
			return
		default:
			if sub == "" {
				sub = a
			}
		}
	}

	r := root()

	switch sub {
	case "", "all":
		doctorAll(r, jsonOut)
	case "artefacts":
		doctorArtefacts(r, jsonOut)
	case "services":
		doctorServices(r, jsonOut)
	case "sync":
		doctorSync(r, jsonOut)
	case "uses-functions":
		doctorUsesFunctions(r, jsonOut)
	case "unused":
		doctorUnused(r, jsonOut)
	default:
		fmt.Fprintf(os.Stderr, "unknown doctor subcommand: %s\n", sub)
		doctorUsage()
		os.Exit(1)
	}
}

func doctorUsage() {
	fmt.Println(`fn doctor — diagnostico read-only del registry y artefactos

Usage:
  fn doctor [subcommand] [--json]

Subcommands:
  (none)|all      Corre todos los checks
  artefacts       Salud de apps y analyses (git, venv, app.md, upstream)
  services        Estado de apps con tag 'service' (systemd + puerto)
  sync            Drift entre pc_locations BD y disco
  uses-functions  Audit imports reales vs uses_functions del app.md
  unused          Funciones del registry sin consumidores

Flags:
  --json          Salida JSON (para scripting/agentes)`)
}

func doctorAll(root string, jsonOut bool) {
	if jsonOut {
		all := map[string]any{}
		if v, err := infra.ArtefactDoctor(root); err == nil {
			all["artefacts"] = v
		} else {
			all["artefacts_error"] = err.Error()
		}
		if v, err := infra.ServicesStatus(root); err == nil {
			all["services"] = v
		} else {
			all["services_error"] = err.Error()
		}
		if v, err := infra.PcLocationsDrift(root, ""); err == nil {
			all["sync"] = v
		} else {
			all["sync_error"] = err.Error()
		}
		if v, err := infra.AuditUsesFunctions(root); err == nil {
			all["uses_functions"] = v
		} else {
			all["uses_functions_error"] = err.Error()
		}
		if v, err := infra.FindUnusedFunctions(root); err == nil {
			all["unused"] = v
		} else {
			all["unused_error"] = err.Error()
		}
		emit(all)
		return
	}

	fmt.Println("=== Artefacts ===")
	doctorArtefacts(root, false)
	fmt.Println("\n=== Services ===")
	doctorServices(root, false)
	fmt.Println("\n=== Sync (pc_locations drift) ===")
	doctorSync(root, false)
	fmt.Println("\n=== uses_functions audit ===")
	doctorUsesFunctions(root, false)
	fmt.Println("\n=== Unused functions ===")
	doctorUnused(root, false)
}

func doctorArtefacts(root string, jsonOut bool) {
	checks, err := infra.ArtefactDoctor(root)
	if err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(1)
	}
	if jsonOut {
		emit(checks)
		return
	}
	bad := 0
	w := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0)
	fmt.Fprintln(w, "STATUS\tTYPE\tID\tISSUES")
	for _, c := range checks {
		status := "OK"
		issues := "-"
		if !c.OK {
			status = "FAIL"
			issues = strings.Join(c.Issues, "; ")
			bad++
		}
		fmt.Fprintf(w, "%s\t%s\t%s\t%s\n", status, c.Type, c.ID, issues)
	}
	w.Flush()
	fmt.Printf("\n%d/%d artefacts healthy.\n", len(checks)-bad, len(checks))
}

func doctorServices(root string, jsonOut bool) {
	statuses, err := infra.ServicesStatus(root)
	if err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(1)
	}
	if jsonOut {
		emit(statuses)
		return
	}
	if len(statuses) == 0 {
		fmt.Println("No services registered (no apps with tag 'service').")
		return
	}
	w := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0)
	fmt.Fprintln(w, "NAME\tUNIT\tACTIVE\tPORT\tLISTENING")
	for _, s := range statuses {
		port := "-"
		listen := "-"
		if s.Port > 0 {
			port = fmt.Sprintf("%d", s.Port)
			listen = fmt.Sprintf("%v", s.PortListening)
		}
		fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\n", s.Name, s.UnitName, s.UnitActive, port, listen)
	}
	w.Flush()
}

func doctorSync(root string, jsonOut bool) {
	drifts, err := infra.PcLocationsDrift(root, "")
	if err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(1)
	}
	if jsonOut {
		emit(drifts)
		return
	}
	if len(drifts) == 0 {
		fmt.Println("No drift detected: pc_locations matches disk.")
		return
	}
	w := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0)
	fmt.Fprintln(w, "TYPE\tID\tDIR\tSTATUS\tISSUE")
	for _, d := range drifts {
		fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\n", d.EntityType, d.EntityID, d.DirPath, d.Status, d.Issue)
	}
	w.Flush()
	fmt.Printf("\n%d drift(s) detected.\n", len(drifts))
}

func doctorUsesFunctions(root string, jsonOut bool) {
	audits, err := infra.AuditUsesFunctions(root)
	if err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(1)
	}
	if jsonOut {
		emit(audits)
		return
	}
	bad := 0
	for _, a := range audits {
		if len(a.Missing) == 0 && len(a.Unused) == 0 {
			continue
		}
		bad++
		fmt.Printf("\n%s (%s)\n", a.AppID, a.Lang)
		if len(a.Missing) > 0 {
			fmt.Printf("  missing in app.md: %s\n", strings.Join(a.Missing, ", "))
		}
		if len(a.Unused) > 0 {
			fmt.Printf("  declared but unused: %s\n", strings.Join(a.Unused, ", "))
		}
	}
	if bad == 0 {
		fmt.Println("All apps have matching uses_functions vs imports.")
	} else {
		fmt.Printf("\n%d/%d apps have drift.\n", bad, len(audits))
	}
}

func doctorUnused(root string, jsonOut bool) {
	unused, err := infra.FindUnusedFunctions(root)
	if err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(1)
	}
	if jsonOut {
		emit(unused)
		return
	}
	if len(unused) == 0 {
		fmt.Println("No unused functions.")
		return
	}
	w := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0)
	fmt.Fprintln(w, "ID\tLANG\tDOMAIN\tAGE_DAYS")
	for _, u := range unused {
		fmt.Fprintf(w, "%s\t%s\t%s\t%d\n", u.ID, u.Lang, u.Domain, u.AgeDays)
	}
	w.Flush()
	fmt.Printf("\n%d unused functions (candidates to remove).\n", len(unused))
}

func emit(v any) {
	b, err := json.MarshalIndent(v, "", "  ")
	if err != nil {
		fmt.Fprintf(os.Stderr, "json error: %v\n", err)
		os.Exit(1)
	}
	fmt.Println(string(b))
}