package insight

import (
	"encoding/json"
	"errors"
	"time"
)

type Module string

type Section string

const PageInsightVersion = "page_insight_v8"

const (
	ModuleOverview     Module = "overview"
	ModulePayments     Module = "payments"
	ModuleFees         Module = "fees"
	ModulePeers        Module = "peers"
	ModuleTransactions Module = "transactions"
	ModuleGrowth       Module = "growth"
)

const (
	SectionFull           Section = "full"
	SectionPast           Section = "past"
	SectionLatestObserved Section = "latest-observed"
	SectionFuture7Days    Section = "future-7-days"
	SectionFuture30Days   Section = "future-30-days"
	SectionFuture90Days   Section = "future-90-days"
	SectionFindings       Section = "findings"
	SectionOptions        Section = "options"
)

var ErrNotFound = errors.New("ai insight: not found")
var ErrUnknownTerminal = errors.New("ai insight: unknown terminal")
var ErrRefreshLimited = errors.New("ai insight: refresh limited")
var ErrRefreshCooldown = errors.New("ai insight: refresh cooldown")
var ErrIdempotencyConflict = errors.New("ai insight: idempotency conflict")
var ErrOnboardingRequired = errors.New("ai insight: onboarding required")

type RefreshCooldownError struct{ NextRefreshAt time.Time }

func (e *RefreshCooldownError) Error() string { return "ai insight: refresh cooldown" }
func (e *RefreshCooldownError) Unwrap() error { return ErrRefreshCooldown }

func ParseModule(value string) (Module, bool) {
	module := Module(value)
	switch module {
	case ModuleOverview, ModulePayments, ModuleFees, ModulePeers, ModuleTransactions, ModuleGrowth:
		return module, true
	default:
		return "", false
	}
}

func ParseSection(module Module, value string) (Section, bool) {
	section := Section(value)
	switch section {
	case SectionPast, SectionLatestObserved, SectionFuture7Days, SectionFuture30Days, SectionFindings, SectionOptions:
		return section, true
	case SectionFuture90Days:
		return section, module == ModuleGrowth
	default:
		return "", false
	}
}

type Confidence string

const (
	ConfidenceHigh             Confidence = "HIGH"
	ConfidenceMedium           Confidence = "MEDIUM"
	ConfidenceLow              Confidence = "LOW"
	ConfidenceInsufficientData Confidence = "INSUFFICIENT_DATA"
)

type Narrative struct {
	Headline   string   `json:"headline"`
	Body       string   `json:"body"`
	EvidenceID []string `json:"evidenceIds"`
}

type Finding struct {
	EvidenceID string     `json:"evidenceId"`
	Title      string     `json:"title"`
	Summary    string     `json:"summary"`
	ScoreBPS   int        `json:"scoreBps"`
	Confidence Confidence `json:"confidence"`
}

type Option struct {
	Title       string   `json:"title"`
	Description string   `json:"description"`
	EvidenceID  []string `json:"evidenceIds"`
}

type CalendarContext struct {
	EventKey          string `json:"eventKey"`
	TitleFA           string `json:"titleFa"`
	StartDate         string `json:"startDate"`
	EndDate           string `json:"endDate"`
	Tone              string `json:"tone"`
	CommercialPosture string `json:"commercialPosture"`
	OfficialHoliday   bool   `json:"officialHoliday"`
	EvidenceSupported bool   `json:"evidenceSupported"`
	OverlapConfounded bool   `json:"overlapConfounded"`
}

type Copy struct {
	Past           Narrative  `json:"past"`
	LatestObserved Narrative  `json:"latestObserved"`
	Future7Days    Narrative  `json:"future7Days"`
	Future30Days   Narrative  `json:"future30Days"`
	Future90Days   *Narrative `json:"future90Days,omitempty"`
	Findings       []Finding  `json:"findings"`
	Options        []Option   `json:"options"`
}

func MergeSection(base, generated Copy, section Section) (Copy, error) {
	switch section {
	case SectionFull:
		return generated, nil
	case SectionPast:
		base.Past = generated.Past
	case SectionLatestObserved:
		base.LatestObserved = generated.LatestObserved
	case SectionFuture7Days:
		base.Future7Days = generated.Future7Days
	case SectionFuture30Days:
		base.Future30Days = generated.Future30Days
	case SectionFuture90Days:
		if generated.Future90Days == nil {
			return Copy{}, errors.New("ai insight: future 90 day section unavailable")
		}
		base.Future90Days = generated.Future90Days
	case SectionFindings:
		base.Findings = generated.Findings
	case SectionOptions:
		base.Options = generated.Options
	default:
		return Copy{}, errors.New("ai insight: invalid section")
	}
	return base, nil
}

type Scope struct {
	TerminalID *string `json:"terminalId"`
	PeriodID   *string `json:"periodId,omitempty"`
}

type PeriodScope struct {
	PeriodID      string
	PeriodType    string
	StartAt       time.Time
	EndAt         time.Time
	JalaliLabelFA string
}

type RefreshState struct {
	State         string     `json:"state"`
	JobID         string     `json:"jobId,omitempty"`
	EventsURL     string     `json:"eventsUrl,omitempty"`
	NextRefreshAt *time.Time `json:"nextRefreshAt,omitempty"`
}

type Snapshot struct {
	InsightID       string                   `json:"insightId"`
	Module          Module                   `json:"module"`
	Revision        int                      `json:"revision"`
	Status          string                   `json:"status"`
	Scope           Scope                    `json:"scope"`
	AsOfDate        string                   `json:"asOfDate"`
	DataThroughDate string                   `json:"dataThroughDate"`
	ForecastStart   string                   `json:"forecastStartDate"`
	Freshness       Freshness                `json:"freshness"`
	DataLagDays     int                      `json:"dataLagDays"`
	Confidence      Confidence               `json:"confidence"`
	Copy            Copy                     `json:"copy"`
	Evidence        json.RawMessage          `json:"evidence"`
	CalendarContext []CalendarContext        `json:"calendarContext"`
	RefreshState    RefreshState             `json:"refreshState"`
	SectionRefresh  map[Section]RefreshState `json:"sectionRefreshState"`
	GeneratedAt     time.Time                `json:"generatedAt"`
}

type Job struct {
	JobID      string    `json:"jobId"`
	SnapshotID string    `json:"snapshotId"`
	Module     Module    `json:"module"`
	Section    Section   `json:"sectionId"`
	State      string    `json:"state"`
	EventsURL  string    `json:"eventsUrl"`
	CreatedAt  time.Time `json:"createdAt"`
	UpdatedAt  time.Time `json:"updatedAt"`
}

type Event struct {
	ID         int64           `json:"eventId"`
	Type       string          `json:"type"`
	Payload    json.RawMessage `json:"payload"`
	OccurredAt time.Time       `json:"occurredAt"`
}

type CreateRequest struct {
	MerchantID     int64
	TerminalID     string
	Module         Module
	Section        Section
	TriggerReason  string
	ManualRefresh  bool
	IdempotencyKey string
	RequestHash    string
	Fingerprint    string
	Time           TimeContext
	Confidence     Confidence
	CatalogVersion string
	Evidence       json.RawMessage
	Period         PeriodScope
}

type ProviderUsage struct {
	InputTokens       int64
	OutputTokens      int64
	ProviderRequests  int64
	LatencyMS         int64
	ProviderRequestID string
	EstimatedCost     string
}

type Completion struct {
	Analysis    Analysis
	AICopy      *Copy
	Status      string
	FailureCode string
	Model       string
	Usage       ProviderUsage
}