package backtest

import "time"

// RunState represents the current state of a backtest run.
type RunState string

const (
	RunStateCreated    RunState = "created"
	RunStateRunning    RunState = "running"
	RunStatePaused     RunState = "paused"
	RunStateStopped    RunState = "stopped"
	RunStateCompleted  RunState = "completed"
	RunStateFailed     RunState = "failed"
	RunStateLiquidated RunState = "liquidated"
)

// PositionSnapshot represents core position data for backtest state and persistence.
type PositionSnapshot struct {
	Symbol           string  `json:"symbol"`
	Side             string  `json:"side"`
	Quantity         float64 `json:"quantity"`
	AvgPrice         float64 `json:"avg_price"`
	Leverage         int     `json:"leverage"`
	LiquidationPrice float64 `json:"liquidation_price"`
	MarginUsed       float64 `json:"margin_used"`
	OpenTime         int64   `json:"open_time"`
	AccumulatedFee   float64 `json:"accumulated_fee,omitempty"` // Opening fees accumulated
}

// BacktestState represents the real-time state during execution (in-memory state).
type BacktestState struct {
	BarIndex      int
	BarTimestamp  int64
	DecisionCycle int

	Cash            float64
	Equity          float64
	UnrealizedPnL   float64
	RealizedPnL     float64
	MaxEquity       float64
	MinEquity       float64
	MaxDrawdownPct  float64
	Positions       map[string]PositionSnapshot
	LastUpdate      time.Time
	Liquidated      bool
	LiquidationNote string
}

// EquityPoint represents a single point on the equity curve.
type EquityPoint struct {
	Timestamp   int64   `json:"ts"`
	Equity      float64 `json:"equity"`
	Available   float64 `json:"available"`
	PnL         float64 `json:"pnl"`
	PnLPct      float64 `json:"pnl_pct"`
	DrawdownPct float64 `json:"dd_pct"`
	Cycle       int     `json:"cycle"`
}

// TradeEvent records a trade execution result or special event (such as liquidation).
type TradeEvent struct {
	Timestamp       int64   `json:"ts"`
	Symbol          string  `json:"symbol"`
	Action          string  `json:"action"`
	Side            string  `json:"side,omitempty"`
	Quantity        float64 `json:"qty"`
	Price           float64 `json:"price"`
	Fee             float64 `json:"fee"`
	Slippage        float64 `json:"slippage"`
	OrderValue      float64 `json:"order_value"`
	RealizedPnL     float64 `json:"realized_pnl"`
	Leverage        int     `json:"leverage,omitempty"`
	Cycle           int     `json:"cycle"`
	PositionAfter   float64 `json:"position_after"`
	LiquidationFlag bool    `json:"liquidation"`
	Note            string  `json:"note,omitempty"`
}

// Metrics summarizes backtest performance metrics.
type Metrics struct {
	TotalReturnPct float64                  `json:"total_return_pct"`
	MaxDrawdownPct float64                  `json:"max_drawdown_pct"`
	SharpeRatio    float64                  `json:"sharpe_ratio"`
	ProfitFactor   float64                  `json:"profit_factor"`
	WinRate        float64                  `json:"win_rate"`
	Trades         int                      `json:"trades"`
	AvgWin         float64                  `json:"avg_win"`
	AvgLoss        float64                  `json:"avg_loss"`
	BestSymbol     string                   `json:"best_symbol"`
	WorstSymbol    string                   `json:"worst_symbol"`
	SymbolStats    map[string]SymbolMetrics `json:"symbol_stats"`
	Liquidated     bool                     `json:"liquidated"`
}

// SymbolMetrics records performance for a single symbol.
type SymbolMetrics struct {
	TotalTrades   int     `json:"total_trades"`
	WinningTrades int     `json:"winning_trades"`
	LosingTrades  int     `json:"losing_trades"`
	TotalPnL      float64 `json:"total_pnl"`
	AvgPnL        float64 `json:"avg_pnl"`
	WinRate       float64 `json:"win_rate"`
}

// Checkpoint represents checkpoint information saved to disk for pause, resume, and crash recovery.
type Checkpoint struct {
	BarIndex        int                       `json:"bar_index"`
	BarTimestamp    int64                     `json:"bar_ts"`
	Cash            float64                   `json:"cash"`
	Equity          float64                   `json:"equity"`
	MaxEquity       float64                   `json:"max_equity"`
	MinEquity       float64                   `json:"min_equity"`
	MaxDrawdownPct  float64                   `json:"max_drawdown_pct"`
	UnrealizedPnL   float64                   `json:"unrealized_pnl"`
	RealizedPnL     float64                   `json:"realized_pnl"`
	Positions       []PositionSnapshot        `json:"positions"`
	DecisionCycle   int                       `json:"decision_cycle"`
	IndicatorsState map[string]map[string]any `json:"indicators_state,omitempty"`
	RNGSeed         int64                     `json:"rng_seed,omitempty"`
	AICacheRef      string                    `json:"ai_cache_ref,omitempty"`
	Liquidated      bool                      `json:"liquidated"`
	LiquidationNote string                    `json:"liquidation_note,omitempty"`
}

// RunMetadata records the summary required for run.json.
type RunMetadata struct {
	RunID     string     `json:"run_id"`
	Label     string     `json:"label,omitempty"`
	UserID    string     `json:"user_id,omitempty"`
	LastError string     `json:"last_error,omitempty"`
	Version   int        `json:"version"`
	State     RunState   `json:"state"`
	CreatedAt time.Time  `json:"created_at"`
	UpdatedAt time.Time  `json:"updated_at"`
	Summary   RunSummary `json:"summary"`
}

// RunSummary represents the summary field in run.json.
type RunSummary struct {
	SymbolCount     int     `json:"symbol_count"`
	DecisionTF      string  `json:"decision_tf"`
	ProcessedBars   int     `json:"processed_bars"`
	ProgressPct     float64 `json:"progress_pct"`
	EquityLast      float64 `json:"equity_last"`
	MaxDrawdownPct  float64 `json:"max_drawdown_pct"`
	Liquidated      bool    `json:"liquidated"`
	LiquidationNote string  `json:"liquidation_note,omitempty"`
}

// StatusPayload is used for /status API responses.
type StatusPayload struct {
	RunID          string            `json:"run_id"`
	State          RunState          `json:"state"`
	ProgressPct    float64           `json:"progress_pct"`
	ProcessedBars  int               `json:"processed_bars"`
	CurrentTime    int64             `json:"current_time"`
	DecisionCycle  int               `json:"decision_cycle"`
	Equity         float64           `json:"equity"`
	UnrealizedPnL  float64           `json:"unrealized_pnl"`
	RealizedPnL    float64           `json:"realized_pnl"`
	Positions      []PositionStatus  `json:"positions,omitempty"`
	Note           string            `json:"note,omitempty"`
	LastError      string            `json:"last_error,omitempty"`
	LastUpdatedIso string            `json:"last_updated_iso"`
}

// PositionStatus represents a position with unrealized P&L for status display.
type PositionStatus struct {
	Symbol           string  `json:"symbol"`
	Side             string  `json:"side"`
	Quantity         float64 `json:"quantity"`
	EntryPrice       float64 `json:"entry_price"`
	MarkPrice        float64 `json:"mark_price"`
	Leverage         int     `json:"leverage"`
	UnrealizedPnL    float64 `json:"unrealized_pnl"`
	UnrealizedPnLPct float64 `json:"unrealized_pnl_pct"`
	MarginUsed       float64 `json:"margin_used"`
}