package app

import (
	"context"
	"errors"
	"fmt"
	"regexp"
	"strings"
	"time"

	"proxyctl/internal/profile"
	"proxyctl/internal/target"
)

// MutationLock serializes all state-changing operations across processes.
type MutationLock interface {
	Lock(context.Context) (unlock func(), err error)
}

// LogEntry is the privacy-safe operation record written to bounded local logs.
type LogEntry struct {
	Time      time.Time
	Operation string
	Target    string
	Result    string
	Detail    string
}

type OperationLogger interface{ Write(LogEntry) error }

type Maintenance struct {
	state   profile.State
	targets []target.Target
	lock    MutationLock
	logger  OperationLogger
}

func NewMaintenance(state profile.State, targets []target.Target, lock MutationLock, logger OperationLogger) *Maintenance {
	return &Maintenance{state: state, targets: append([]target.Target(nil), targets...), lock: lock, logger: logger}
}

type Diagnostic struct {
	TargetID string
	Check    target.Check
}

type DoctorReport struct{ Diagnostics []Diagnostic }

func (r DoctorReport) Healthy() bool {
	for _, diagnostic := range r.Diagnostics {
		if !diagnostic.Check.OK {
			return false
		}
	}
	return true
}
func (r DoctorReport) String() string {
	var output strings.Builder
	for _, diagnostic := range r.Diagnostics {
		status := "OK"
		if !diagnostic.Check.OK {
			status = "FAIL"
		}
		name := diagnostic.Check.Name
		if diagnostic.TargetID != "" {
			name = diagnostic.TargetID + ": " + name
		}
		fmt.Fprintf(&output, "[%s] %s — %s\n", status, name, profile.RedactText(diagnostic.Check.Evidence))
	}
	return output.String()
}

// Doctor only invokes observational Target methods.
func (m *Maintenance) Doctor(ctx context.Context, applicationChecks []target.Check) DoctorReport {
	report := DoctorReport{}
	for _, check := range applicationChecks {
		check.Evidence = profile.RedactText(check.Evidence)
		report.Diagnostics = append(report.Diagnostics, Diagnostic{Check: check})
	}
	active := activeFromState(m.state)
	for _, adapter := range m.targets {
		availability := adapter.Availability(ctx)
		report.Diagnostics = append(report.Diagnostics, Diagnostic{TargetID: adapter.ID(), Check: target.Check{Name: "Target availability", OK: availability.Available, Evidence: availability.Evidence}})
		inspection := adapter.Inspect(ctx, active)
		report.Diagnostics = append(report.Diagnostics, Diagnostic{TargetID: adapter.ID(), Check: target.Check{Name: "detected state", OK: inspection.State != target.Drifted, Evidence: string(inspection.State) + ": " + inspection.Evidence}})
		if diagnosable, ok := adapter.(target.Diagnosable); ok {
			for _, check := range diagnosable.DiagnosticChecks(ctx, active) {
				check.Evidence = profile.RedactText(check.Evidence)
				report.Diagnostics = append(report.Diagnostics, Diagnostic{TargetID: adapter.ID(), Check: check})
			}
		}
	}
	return report
}

type ResetTargetResult struct {
	TargetID   string
	Inspection target.Inspection
	Skipped    bool
	Err        error
}
type ResetResult struct {
	Cancelled bool
	Targets   []ResetTargetResult
	Err       error
}

func (m *Maintenance) Reset(ctx context.Context, confirmed bool) ResetResult {
	if !confirmed {
		return ResetResult{Cancelled: true}
	}
	if m.lock == nil {
		return ResetResult{Err: errors.New("mutation lock is not configured")}
	}
	unlock, err := m.lock.Lock(ctx)
	if err != nil {
		return ResetResult{Err: fmt.Errorf("lock proxyctl mutation: %w", err)}
	}
	defer unlock()
	active := activeFromState(m.state)
	result := ResetResult{}
	for _, adapter := range m.targets {
		inspection := adapter.Inspect(ctx, active)
		if inspection.State != target.Enabled && inspection.State != target.Drifted {
			result.Targets = append(result.Targets, ResetTargetResult{TargetID: adapter.ID(), Inspection: inspection, Skipped: true})
			continue
		}
		operation := adapter.SetDesired(ctx, false, active)
		detail, outcome := operation.Inspection.Evidence, "success"
		if operation.Err != nil {
			outcome = "failure"
			detail = operation.Err.Error()
			result.Err = errors.Join(result.Err, fmt.Errorf("reset %s Target: %w", adapter.ID(), redactError(operation.Err)))
		}
		detail = RedactLogDetail(detail)
		if m.logger != nil {
			_ = m.logger.Write(LogEntry{Time: time.Now(), Operation: "reset", Target: adapter.ID(), Result: outcome, Detail: detail})
		}
		result.Targets = append(result.Targets, ResetTargetResult{TargetID: adapter.ID(), Inspection: operation.Inspection, Err: redactError(operation.Err)})
	}
	return result
}

func activeFromState(state profile.State) *profile.Profile {
	for i := range state.Profiles {
		if state.Profiles[i].Name == state.ActiveProfile {
			value := state.Profiles[i]
			return &value
		}
	}
	return nil
}

var authenticatedURL = regexp.MustCompile(`(?i)(?:https?|socks5h?)://[^\s'\"<>]*@[^\s'\"<>]+`)

// RedactLogDetail omits complete authenticated URLs, not just their passwords.
func RedactLogDetail(value string) string {
	value = authenticatedURL.ReplaceAllString(value, "[REDACTED AUTHENTICATED URL]")
	return profile.RedactText(value)
}
func redactError(err error) error {
	if err == nil {
		return nil
	}
	return errors.New(profile.RedactText(err.Error()))
}