package db

import (
	"database/sql"
	"fmt"
	"strings"
)

// AIDecisionRecord is one persisted fleet AI decision cycle.
type AIDecisionRecord struct {
	ID               int64  `json:"id"`
	AgentID          string `json:"agent_id"`
	PromptHash       string `json:"prompt_hash"`
	Response         string `json:"response"`
	CommandsExecuted string `json:"commands_executed"`
	Timestamp        string `json:"ts"`
}

func (d *Database) ensureAIDecisionsTable() error {
	_, err := d.Exec(`CREATE TABLE IF NOT EXISTS ai_decisions (
		id INTEGER PRIMARY KEY AUTOINCREMENT,
		agent_id TEXT NOT NULL,
		prompt_hash TEXT NOT NULL DEFAULT '',
		response TEXT NOT NULL DEFAULT '',
		commands_executed TEXT NOT NULL DEFAULT '',
		ts DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
	)`)
	if err != nil {
		return err
	}
	_, _ = d.Exec(`CREATE INDEX IF NOT EXISTS idx_ai_decisions_agent ON ai_decisions(agent_id)`)
	_, _ = d.Exec(`CREATE INDEX IF NOT EXISTS idx_ai_decisions_ts ON ai_decisions(ts)`)
	return nil
}

// InsertAIDecision logs one fleet AI decision cycle.
func (d *Database) InsertAIDecision(agentID, promptHash, response, commandsExecuted string) error {
	if d == nil {
		return nil
	}
	if err := d.ensureAIDecisionsTable(); err != nil {
		return err
	}
	_, err := d.Exec(
		`INSERT INTO ai_decisions (agent_id, prompt_hash, response, commands_executed) VALUES (?, ?, ?, ?)`,
		agentID, promptHash, response, commandsExecuted,
	)
	return err
}

// ListAIDecisions returns the most recent decisions for an agent (or all agents when agentID empty).
func (d *Database) ListAIDecisions(agentID string, limit int) ([]AIDecisionRecord, error) {
	if d == nil {
		return nil, nil
	}
	if err := d.ensureAIDecisionsTable(); err != nil {
		return nil, err
	}
	if limit <= 0 {
		limit = 50
	}
	if limit > 500 {
		limit = 500
	}

	var rows *sql.Rows
	var err error
	agentID = strings.TrimSpace(agentID)
	if agentID != "" {
		rows, err = d.Query(
			`SELECT id, agent_id, prompt_hash, response, commands_executed, ts
			 FROM ai_decisions WHERE agent_id = ? ORDER BY id DESC LIMIT ?`,
			agentID, limit,
		)
	} else {
		rows, err = d.Query(
			`SELECT id, agent_id, prompt_hash, response, commands_executed, ts
			 FROM ai_decisions ORDER BY id DESC LIMIT ?`,
			limit,
		)
	}
	if err != nil {
		return nil, fmt.Errorf("list ai decisions: %w", err)
	}
	defer rows.Close()

	out := make([]AIDecisionRecord, 0, limit)
	for rows.Next() {
		var rec AIDecisionRecord
		var ts string
		if err := rows.Scan(&rec.ID, &rec.AgentID, &rec.PromptHash, &rec.Response, &rec.CommandsExecuted, &ts); err != nil {
			return nil, err
		}
		rec.Timestamp = ts
		out = append(out, rec)
	}
	return out, rows.Err()
}