package cli

import (
	"context"
	"errors"
	"fmt"
	"io"
	"os"
	"strings"

	"forge.lclr.dev/AI/mcp-framework/config"
	"forge.lclr.dev/AI/mcp-framework/manifest"
	"forge.lclr.dev/AI/mcp-framework/secretstore"
)

type DoctorStatus string

const (
	DoctorStatusOK   DoctorStatus = "ok"
	DoctorStatusWarn DoctorStatus = "warn"
	DoctorStatusFail DoctorStatus = "fail"
)

type DoctorResult struct {
	Name    string
	Status  DoctorStatus
	Summary string
	Detail  string
}

type DoctorCheck func(context.Context) DoctorResult

type DoctorReport struct {
	Results []DoctorResult
}

type DoctorSummary struct {
	OK    int
	Warn  int
	Fail  int
	Total int
}

type DoctorSecret struct {
	Name  string
	Label string
}

type DoctorManifestValidator func(manifest.File, string) []string

type DoctorOptions struct {
	ConfigCheck               DoctorCheck
	SecretStoreCheck          DoctorCheck
	SecretBackendPolicy       secretstore.BackendPolicy
	RequiredSecrets           []DoctorSecret
	SecretStoreFactory        func() (secretstore.Store, error)
	ManifestDir               string
	ManifestValidator         DoctorManifestValidator
	ManifestCheck             DoctorCheck
	ConnectivityCheck         DoctorCheck
	BitwardenOptions          BitwardenDoctorOptions
	DisableAutoBitwardenCheck bool
	ExtraChecks               []DoctorCheck
}

type BitwardenDoctorOptions struct {
	Command   string
	Debug     bool
	Shell     string
	LookupEnv func(string) (string, bool)
}

var checkBitwardenReady = secretstore.EnsureBitwardenReady

func RunDoctor(ctx context.Context, options DoctorOptions) DoctorReport {
	checks := make([]DoctorCheck, 0, 5+len(options.ExtraChecks))

	if options.ConfigCheck != nil {
		checks = append(checks, options.ConfigCheck)
	}
	if options.SecretStoreCheck != nil {
		checks = append(checks, options.SecretStoreCheck)
	}
	if len(options.RequiredSecrets) > 0 && options.SecretStoreFactory != nil {
		checks = append(checks, RequiredSecretsCheck(options.SecretStoreFactory, options.RequiredSecrets))
	}
	if options.ManifestCheck != nil {
		checks = append(checks, options.ManifestCheck)
	} else if strings.TrimSpace(options.ManifestDir) != "" {
		checks = append(checks, ManifestCheck(options.ManifestDir, options.ManifestValidator))
	}
	if options.ConnectivityCheck != nil {
		checks = append(checks, options.ConnectivityCheck)
	}
	if shouldAutoIncludeBitwardenCheck(options) {
		checks = append(checks, BitwardenReadyCheck(options.BitwardenOptions))
	}
	checks = append(checks, options.ExtraChecks...)

	results := make([]DoctorResult, 0, len(checks))
	for _, check := range checks {
		if check == nil {
			continue
		}
		results = append(results, normalizeDoctorResult(check(ctx)))
	}

	return DoctorReport{Results: results}
}

func (r DoctorReport) Summary() DoctorSummary {
	summary := DoctorSummary{Total: len(r.Results)}
	for _, result := range r.Results {
		switch result.Status {
		case DoctorStatusOK:
			summary.OK++
		case DoctorStatusWarn:
			summary.Warn++
		case DoctorStatusFail:
			summary.Fail++
		default:
			summary.Fail++
		}
	}
	return summary
}

func (r DoctorReport) HasFailures() bool {
	return r.Summary().Fail > 0
}

func RenderDoctorReport(w io.Writer, report DoctorReport) error {
	for _, result := range report.Results {
		if _, err := fmt.Fprintf(w, "[%s] %s: %s\n", doctorLabel(result.Status), result.Name, result.Summary); err != nil {
			return err
		}
		if detail := strings.TrimSpace(result.Detail); detail != "" {
			if _, err := fmt.Fprintf(w, "      %s\n", detail); err != nil {
				return err
			}
		}
	}

	summary := report.Summary()
	_, err := fmt.Fprintf(
		w,
		"Summary: %d ok, %d warning(s), %d failure(s), %d total\n",
		summary.OK,
		summary.Warn,
		summary.Fail,
		summary.Total,
	)
	return err
}

func NewConfigCheck[T any](store config.Store[T]) DoctorCheck {
	return func(context.Context) DoctorResult {
		path, err := store.ConfigPath()
		if err != nil {
			return DoctorResult{
				Name:    "config",
				Status:  DoctorStatusFail,
				Summary: "cannot resolve config path",
				Detail:  err.Error(),
			}
		}

		info, err := os.Stat(path)
		switch {
		case err == nil && info.IsDir():
			return DoctorResult{
				Name:    "config",
				Status:  DoctorStatusFail,
				Summary: "config path is a directory",
				Detail:  path,
			}
		case err == nil:
			if _, err := store.Load(path); err != nil {
				return DoctorResult{
					Name:    "config",
					Status:  DoctorStatusFail,
					Summary: "config file is unreadable or invalid",
					Detail:  err.Error(),
				}
			}
			return DoctorResult{
				Name:    "config",
				Status:  DoctorStatusOK,
				Summary: "config file is readable",
				Detail:  path,
			}
		case errors.Is(err, os.ErrNotExist):
			return DoctorResult{
				Name:    "config",
				Status:  DoctorStatusWarn,
				Summary: "config file is missing",
				Detail:  path,
			}
		default:
			return DoctorResult{
				Name:    "config",
				Status:  DoctorStatusFail,
				Summary: "cannot access config file",
				Detail:  err.Error(),
			}
		}
	}
}

func SecretStoreAvailabilityCheck(factory func() (secretstore.Store, error)) DoctorCheck {
	return func(context.Context) DoctorResult {
		if factory == nil {
			return DoctorResult{
				Name:    "secret-store",
				Status:  DoctorStatusWarn,
				Summary: "secret store check is not configured",
			}
		}

		_, err := factory()
		if err != nil {
			return DoctorResult{
				Name:    "secret-store",
				Status:  DoctorStatusFail,
				Summary: "secret backend is unavailable",
				Detail:  err.Error(),
			}
		}

		return DoctorResult{
			Name:    "secret-store",
			Status:  DoctorStatusOK,
			Summary: "secret backend is available",
		}
	}
}

func BitwardenReadyCheck(options BitwardenDoctorOptions) DoctorCheck {
	return func(context.Context) DoctorResult {
		err := checkBitwardenReady(secretstore.Options{
			BitwardenCommand: strings.TrimSpace(options.Command),
			BitwardenDebug:   options.Debug,
			Shell:            strings.TrimSpace(options.Shell),
			LookupEnv:        options.LookupEnv,
		})
		if err == nil {
			return DoctorResult{
				Name:    "bitwarden",
				Status:  DoctorStatusOK,
				Summary: "bitwarden CLI is ready",
			}
		}

		switch {
		case errors.Is(err, secretstore.ErrBWNotLoggedIn):
			return DoctorResult{
				Name:    "bitwarden",
				Status:  DoctorStatusFail,
				Summary: "bitwarden login is required",
				Detail:  err.Error(),
			}
		case errors.Is(err, secretstore.ErrBWLocked):
			return DoctorResult{
				Name:    "bitwarden",
				Status:  DoctorStatusFail,
				Summary: "bitwarden vault is locked or BW_SESSION is missing",
				Detail:  err.Error(),
			}
		case errors.Is(err, secretstore.ErrBWUnavailable):
			return DoctorResult{
				Name:    "bitwarden",
				Status:  DoctorStatusFail,
				Summary: "bitwarden CLI is unavailable",
				Detail:  err.Error(),
			}
		default:
			return DoctorResult{
				Name:    "bitwarden",
				Status:  DoctorStatusFail,
				Summary: "bitwarden readiness check failed",
				Detail:  err.Error(),
			}
		}
	}
}

func shouldAutoIncludeBitwardenCheck(options DoctorOptions) bool {
	if options.DisableAutoBitwardenCheck {
		return false
	}

	if options.SecretBackendPolicy == secretstore.BackendBitwardenCLI {
		return true
	}

	if options.SecretStoreFactory == nil {
		return false
	}

	store, err := options.SecretStoreFactory()
	if err == nil {
		return secretstore.EffectiveBackendPolicy(store) == secretstore.BackendBitwardenCLI
	}

	if errors.Is(err, secretstore.ErrBWNotLoggedIn) ||
		errors.Is(err, secretstore.ErrBWLocked) ||
		errors.Is(err, secretstore.ErrBWUnavailable) {
		return true
	}

	return strings.Contains(strings.ToLower(strings.TrimSpace(err.Error())), "bitwarden")
}

func RequiredSecretsCheck(factory func() (secretstore.Store, error), required []DoctorSecret) DoctorCheck {
	return func(context.Context) DoctorResult {
		store, err := factory()
		if err != nil {
			return DoctorResult{
				Name:    "required-secrets",
				Status:  DoctorStatusFail,
				Summary: "cannot inspect required secrets",
				Detail:  err.Error(),
			}
		}

		var missing []string
		for _, secret := range required {
			name := strings.TrimSpace(secret.Name)
			if name == "" {
				continue
			}

			_, err := store.GetSecret(name)
			switch {
			case err == nil:
			case errors.Is(err, secretstore.ErrNotFound):
				if label := strings.TrimSpace(secret.Label); label != "" {
					missing = append(missing, fmt.Sprintf("%s (%s)", name, label))
				} else {
					missing = append(missing, name)
				}
			default:
				return DoctorResult{
					Name:    "required-secrets",
					Status:  DoctorStatusFail,
					Summary: fmt.Sprintf("cannot read secret %q", name),
					Detail:  err.Error(),
				}
			}
		}

		if len(missing) > 0 {
			return DoctorResult{
				Name:    "required-secrets",
				Status:  DoctorStatusFail,
				Summary: "required secrets are missing",
				Detail:  strings.Join(missing, ", "),
			}
		}

		return DoctorResult{
			Name:    "required-secrets",
			Status:  DoctorStatusOK,
			Summary: "all required secrets are present",
		}
	}
}

func RequiredResolvedFieldsCheck(options ResolveOptions) DoctorCheck {
	required := requiredFieldNames(options.Fields)

	return func(context.Context) DoctorResult {
		if len(required) == 0 {
			return DoctorResult{
				Name:    "required-profile-fields",
				Status:  DoctorStatusWarn,
				Summary: "no required profile field is configured",
			}
		}

		resolution, err := ResolveFields(options)
		if err != nil {
			return DoctorResult{
				Name:    "required-profile-fields",
				Status:  DoctorStatusFail,
				Summary: resolveFieldsErrorSummary(err),
				Detail:  FormatResolveFieldsError(err),
			}
		}

		sources := make([]string, 0, len(required))
		for _, name := range required {
			field, ok := resolution.Get(name)
			if !ok || !field.Found {
				return DoctorResult{
					Name:    "required-profile-fields",
					Status:  DoctorStatusFail,
					Summary: "required profile values are missing",
					Detail:  name,
				}
			}
			sources = append(sources, fmt.Sprintf("%s=%s", name, field.Source))
		}

		return DoctorResult{
			Name:    "required-profile-fields",
			Status:  DoctorStatusOK,
			Summary: "required profile values are resolved",
			Detail:  strings.Join(sources, ", "),
		}
	}
}

func FormatResolveFieldsError(err error) string {
	if err == nil {
		return ""
	}

	var missing *MissingRequiredValuesError
	if errors.As(err, &missing) {
		if len(missing.Fields) == 0 {
			return "missing required configuration values"
		}
		return strings.Join(missing.Fields, ", ")
	}

	var lookupErr *SourceLookupError
	if errors.As(err, &lookupErr) {
		key := strings.TrimSpace(lookupErr.Key)
		if key == "" {
			key = lookupErr.Field
		}
		return fmt.Sprintf(
			"field %q via source %q (key %q): %v",
			lookupErr.Field,
			lookupErr.Source,
			key,
			lookupErr.Err,
		)
	}

	return err.Error()
}

func ManifestCheck(startDir string, validator DoctorManifestValidator) DoctorCheck {
	return func(context.Context) DoctorResult {
		file, path, err := manifest.LoadDefault(startDir)
		if err != nil {
			return DoctorResult{
				Name:    "manifest",
				Status:  DoctorStatusFail,
				Summary: "manifest is missing or invalid",
				Detail:  err.Error(),
			}
		}

		if validator != nil {
			issues := validator(file, path)
			if len(issues) > 0 {
				return DoctorResult{
					Name:    "manifest",
					Status:  DoctorStatusFail,
					Summary: "manifest validation failed",
					Detail:  strings.Join(issues, "; "),
				}
			}
		}

		return DoctorResult{
			Name:    "manifest",
			Status:  DoctorStatusOK,
			Summary: "manifest is valid",
			Detail:  path,
		}
	}
}

func normalizeDoctorResult(result DoctorResult) DoctorResult {
	result.Name = strings.TrimSpace(result.Name)
	if result.Name == "" {
		result.Name = "unnamed-check"
	}

	result.Summary = strings.TrimSpace(result.Summary)
	if result.Summary == "" {
		result.Summary = "no details provided"
	}

	result.Detail = strings.TrimSpace(result.Detail)
	switch result.Status {
	case DoctorStatusOK, DoctorStatusWarn, DoctorStatusFail:
	default:
		result.Status = DoctorStatusFail
	}

	return result
}

func doctorLabel(status DoctorStatus) string {
	switch status {
	case DoctorStatusOK:
		return "OK"
	case DoctorStatusWarn:
		return "WARN"
	default:
		return "FAIL"
	}
}

func requiredFieldNames(specs []FieldSpec) []string {
	required := make([]string, 0, len(specs))
	seen := make(map[string]struct{}, len(specs))

	for _, spec := range specs {
		if !spec.Required {
			continue
		}

		name := strings.TrimSpace(spec.Name)
		if name == "" {
			continue
		}
		if _, ok := seen[name]; ok {
			continue
		}

		seen[name] = struct{}{}
		required = append(required, name)
	}

	return required
}

func resolveFieldsErrorSummary(err error) string {
	var missing *MissingRequiredValuesError
	if errors.As(err, &missing) {
		return "required profile values are missing"
	}

	var lookupErr *SourceLookupError
	if errors.As(err, &lookupErr) {
		return fmt.Sprintf("cannot resolve profile value %q", lookupErr.Field)
	}

	return "profile resolution failed"
}