// Package domain holds the core commitment types and validation, ported from
// the original Rust implementation. These are pure data types with no I/O.
package domain

import (
	"errors"
	"strings"
	"time"

	"github.com/google/uuid"
)

const PolicySchemaVersion = 1

type CommitmentSource string

const (
	SourceManual    CommitmentSource = "manual"
	SourcePlanner   CommitmentSource = "planner"
	SourceRecurring CommitmentSource = "recurring"
	SourceRecovery  CommitmentSource = "recovery"
	SourceTemplate  CommitmentSource = "template"
)

type CommitmentState string

const (
	CommitmentDraft     CommitmentState = "draft"
	CommitmentActive    CommitmentState = "active"
	CommitmentPaused    CommitmentState = "paused"
	CommitmentCompleted CommitmentState = "completed"
	CommitmentAbandoned CommitmentState = "abandoned"
	CommitmentViolated  CommitmentState = "violated"
)

type RuntimeState string

const (
	RuntimeLocked        RuntimeState = "locked"
	RuntimePlanning      RuntimeState = "planning"
	RuntimeActive        RuntimeState = "active"
	RuntimeTransition    RuntimeState = "transition"
	RuntimeReview        RuntimeState = "review"
	RuntimeAdminOverride RuntimeState = "admin_override"
)

type EnforcementLevel string

const (
	EnforcementObserve EnforcementLevel = "observe"
	EnforcementWarn    EnforcementLevel = "warn"
	EnforcementBlock   EnforcementLevel = "block"
	EnforcementLocked  EnforcementLevel = "locked"
)

// AllowedContext is carried by PolicySnapshot. Matching logic arrives in a
// later milestone; M0 only stores it.
type AllowedContext struct {
	WindowClasses         []string `json:"window_classes"`
	WindowTitleSubstrings []string `json:"window_title_substrings"`
	Domains               []string `json:"domains"`
	Repos                 []string `json:"repos"`
	Commands              []string `json:"commands"`
}

type Commitment struct {
	ID                string           `json:"id"`
	CreatedAtUnixSecs int64            `json:"created_at_unix_secs"`
	Source            CommitmentSource `json:"source"`
	NextAction        string           `json:"next_action"`
	SuccessCondition  string           `json:"success_condition"`
	TimeboxSecs       int64            `json:"timebox_secs"`
	State             CommitmentState  `json:"state"`
}

type PolicySnapshot struct {
	ID                string           `json:"id"`
	CommitmentID      string           `json:"commitment_id"`
	SchemaVersion     int              `json:"schema_version"`
	CreatedAtUnixSecs int64            `json:"created_at_unix_secs"`
	RuntimeState      RuntimeState     `json:"runtime_state"`
	EnforcementLevel  EnforcementLevel `json:"enforcement_level"`
	AllowedContext    AllowedContext   `json:"allowed_context"`
}

var (
	ErrMissingNextAction       = errors.New("next action is required")
	ErrMissingSuccessCondition = errors.New("success condition is required")
	ErrMissingTimebox          = errors.New("timebox must be nonzero")
)

// NewManual builds a validated draft commitment from user input.
func NewManual(nextAction, successCondition string, timebox time.Duration) (Commitment, error) {
	nextAction = strings.TrimSpace(nextAction)
	successCondition = strings.TrimSpace(successCondition)
	if nextAction == "" {
		return Commitment{}, ErrMissingNextAction
	}
	if successCondition == "" {
		return Commitment{}, ErrMissingSuccessCondition
	}
	if timebox <= 0 {
		return Commitment{}, ErrMissingTimebox
	}
	return Commitment{
		ID:                "commitment-" + uuid.Must(uuid.NewV7()).String(),
		CreatedAtUnixSecs: time.Now().Unix(),
		Source:            SourceManual,
		NextAction:        nextAction,
		SuccessCondition:  successCondition,
		TimeboxSecs:       int64(timebox.Seconds()),
		State:             CommitmentDraft,
	}, nil
}

// ForRuntime builds a minimal accepted policy snapshot for a commitment.
func ForRuntime(commitmentID string, runtime RuntimeState, level EnforcementLevel) PolicySnapshot {
	return PolicySnapshot{
		ID:                "policy-" + uuid.Must(uuid.NewV7()).String(),
		CommitmentID:      commitmentID,
		SchemaVersion:     PolicySchemaVersion,
		CreatedAtUnixSecs: time.Now().Unix(),
		RuntimeState:      runtime,
		EnforcementLevel:  level,
		AllowedContext:    AllowedContext{},
	}
}