//go:build llm_script

package main

import (
	"database/sql"
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"sort"
	"strings"
	"time"

	_ "github.com/lib/pq"
)

type CoverageDay struct {
	Date            string
	OfficialRelease bool
	PromoCampaign   bool
	NewModel        bool
	PriceChange     bool
}

func (d CoverageDay) HasTrueEvent() bool {
	return d.OfficialRelease || d.PromoCampaign || d.NewModel || d.PriceChange
}

func (d CoverageDay) EventLabels() []string {
	var labels []string
	if d.OfficialRelease {
		labels = append(labels, "official_release")
	}
	if d.PromoCampaign {
		labels = append(labels, "promo_campaign")
	}
	if d.NewModel {
		labels = append(labels, "new_model")
	}
	if d.PriceChange {
		labels = append(labels, "price_change")
	}
	return labels
}

type CoverageSummary struct {
	TotalDays   int
	CoveredDays int
	CoveragePct float64
}

type CoveragePromoDefinition struct {
	Date string `json:"date"`
}

func main() {
	if len(os.Args) != 3 {
		fmt.Fprintln(os.Stderr, "用法: go run -tags llm_script scripts/report_event_coverage.go YYYY-MM-DD YYYY-MM-DD")
		os.Exit(2)
	}

	startDate, endDate, err := parseCoverageArgs(os.Args[1], os.Args[2])
	if err != nil {
		fmt.Fprintln(os.Stderr, "参数错误:", err)
		os.Exit(2)
	}

	dsn := os.Getenv("DATABASE_URL")
	if dsn == "" {
		dsn = "postgres://long@/llm_intelligence?host=/var/run/postgresql"
	}

	db, err := sql.Open("postgres", dsn)
	if err != nil {
		fmt.Fprintln(os.Stderr, "连接数据库失败:", err)
		os.Exit(1)
	}
	defer db.Close()

	days, err := collectCoverageDays(db, startDate, endDate)
	if err != nil {
		fmt.Fprintln(os.Stderr, "统计覆盖率失败:", err)
		os.Exit(1)
	}
	if len(days) == 0 {
		fmt.Fprintln(os.Stderr, "指定范围内没有已生成的日报记录")
		os.Exit(1)
	}

	summary := summarizeCoverage(days)
	fmt.Printf("V2 事件覆盖率报告 [%s, %s]\n", startDate, endDate)
	for _, day := range days {
		status := "MISS"
		if day.HasTrueEvent() {
			status = "PASS"
		}
		fmt.Printf("%s\t%s\t%s\n", day.Date, status, strings.Join(day.EventLabels(), ", "))
	}
	fmt.Printf("\n总日报天数: %d\n", summary.TotalDays)
	fmt.Printf("命中真实变化事件天数: %d\n", summary.CoveredDays)
	fmt.Printf("覆盖率: %.2f%%\n", summary.CoveragePct)

	if summary.CoveragePct < 80 {
		os.Exit(1)
	}
}

func parseCoverageArgs(start, end string) (string, string, error) {
	startDate, err := time.Parse("2006-01-02", start)
	if err != nil {
		return "", "", fmt.Errorf("开始日期格式不正确")
	}
	endDate, err := time.Parse("2006-01-02", end)
	if err != nil {
		return "", "", fmt.Errorf("结束日期格式不正确")
	}
	if endDate.Before(startDate) {
		return "", "", fmt.Errorf("结束日期不能早于开始日期")
	}
	return startDate.Format("2006-01-02"), endDate.Format("2006-01-02"), nil
}

func collectCoverageDays(db *sql.DB, startDate, endDate string) ([]CoverageDay, error) {
	reportDates, err := loadGeneratedReportDates(db, startDate, endDate)
	if err != nil {
		return nil, err
	}
	promoDates, err := loadCoveragePromoDates()
	if err != nil {
		return nil, err
	}

	var days []CoverageDay
	for _, date := range reportDates {
		officialRelease, err := hasOfficialRelease(db, date)
		if err != nil {
			return nil, err
		}
		newModel, err := hasNewModel(db, date)
		if err != nil {
			return nil, err
		}
		priceChange, err := hasPriceChange(db, date)
		if err != nil {
			return nil, err
		}
		days = append(days, CoverageDay{
			Date:            date,
			OfficialRelease: officialRelease,
			PromoCampaign:   promoDates[date],
			NewModel:        newModel,
			PriceChange:     priceChange,
		})
	}

	sort.Slice(days, func(i, j int) bool {
		return days[i].Date < days[j].Date
	})
	return days, nil
}

func loadGeneratedReportDates(db *sql.DB, startDate, endDate string) ([]string, error) {
	rows, err := db.Query(`
		SELECT DISTINCT report_date::text
		FROM daily_report
		WHERE report_date BETWEEN $1::date AND $2::date
		  AND status = 'generated'
		ORDER BY report_date
	`, startDate, endDate)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var dates []string
	for rows.Next() {
		var date string
		if err := rows.Scan(&date); err != nil {
			return nil, err
		}
		dates = append(dates, date)
	}
	return dates, rows.Err()
}

func hasOfficialRelease(db *sql.DB, date string) (bool, error) {
	var exists bool
	err := db.QueryRow(`
		WITH latest_prices AS (
			SELECT
				rp.model_id,
				COALESCE(o.type, 'reseller') AS operator_type,
				ROW_NUMBER() OVER (
					PARTITION BY rp.model_id
					ORDER BY rp.effective_date DESC NULLS LAST, rp.id DESC
				) AS rn
			FROM region_pricing rp
			LEFT JOIN operator o ON rp.operator_id = o.id
		)
		SELECT EXISTS (
			SELECT 1
			FROM models m
			LEFT JOIN latest_prices lp ON lp.model_id = m.id AND lp.rn = 1
			WHERE m.deleted_at IS NULL
			  AND m.release_date = $1::date
			  AND COALESCE(m.source_url, '') <> ''
			  AND COALESCE(lp.operator_type, 'reseller') IN ('official', 'cloud')
		)
	`, date).Scan(&exists)
	return exists, err
}

func hasNewModel(db *sql.DB, date string) (bool, error) {
	var exists bool
	err := db.QueryRow(`
		SELECT EXISTS (
			SELECT 1
			FROM models
			WHERE deleted_at IS NULL
			  AND DATE(created_at) = $1::date
		)
	`, date).Scan(&exists)
	return exists, err
}

func hasPriceChange(db *sql.DB, date string) (bool, error) {
	var exists bool
	err := db.QueryRow(`
		SELECT EXISTS (
			SELECT 1
			FROM pricing_history
			WHERE DATE(changed_at) = $1::date
			  AND (
				COALESCE(old_input_price, 0) <> COALESCE(new_input_price, 0)
				OR COALESCE(old_output_price, 0) <> COALESCE(new_output_price, 0)
			  )
		)
	`, date).Scan(&exists)
	return exists, err
}

func loadCoveragePromoDates() (map[string]bool, error) {
	path, err := resolveCoveragePromoDataPath()
	if err != nil {
		if os.IsNotExist(err) {
			return map[string]bool{}, nil
		}
		return nil, err
	}

	body, err := os.ReadFile(path)
	if err != nil {
		return nil, err
	}

	var definitions []CoveragePromoDefinition
	if err := json.Unmarshal(body, &definitions); err != nil {
		return nil, err
	}

	dates := make(map[string]bool, len(definitions))
	for _, definition := range definitions {
		if strings.TrimSpace(definition.Date) != "" {
			dates[definition.Date] = true
		}
	}
	return dates, nil
}

func resolveCoveragePromoDataPath() (string, error) {
	candidates := []string{
		filepath.Join("scripts", "testdata", "report_promo_campaigns.json"),
		filepath.Join("testdata", "report_promo_campaigns.json"),
	}
	for _, candidate := range candidates {
		if _, err := os.Stat(candidate); err == nil {
			return candidate, nil
		}
	}
	return "", os.ErrNotExist
}

func summarizeCoverage(days []CoverageDay) CoverageSummary {
	summary := CoverageSummary{TotalDays: len(days)}
	for _, day := range days {
		if day.HasTrueEvent() {
			summary.CoveredDays++
		}
	}
	if summary.TotalDays > 0 {
		summary.CoveragePct = float64(summary.CoveredDays) * 100 / float64(summary.TotalDays)
	}
	return summary
}