package server

import (
	"fmt"
	"net/http"
	"strconv"
	"strings"
	"time"
	"weatherstation/core/internal/data"
)

import "github.com/gin-gonic/gin"

func handleHealth(c *gin.Context) {
	c.JSON(http.StatusOK, gin.H{"status": "ok", "ts": time.Now().UTC().Format(time.RFC3339)})
}

func handleSystemStatus(c *gin.Context) {
	online := data.OnlineDevices()
	c.JSON(http.StatusOK, gin.H{
		"online_devices": online,
		"server_time":    time.Now().Format("2006-01-02 15:04:05"),
	})
}

func handleStations(c *gin.Context) {
	stations, err := data.Stations()
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("query stations failed: %v", err)})
		return
	}
	for i := range stations {
		if len(stations[i].StationID) > 6 {
			hexID := stations[i].StationID[len(stations[i].StationID)-6:]
			if decimalID, err := strconv.ParseInt(hexID, 16, 64); err == nil {
				stations[i].DecimalID = strconv.FormatInt(decimalID, 10)
			}
		}
	}
	c.JSON(http.StatusOK, stations)
}

func handleData(c *gin.Context) {
	idParam := c.Query("hex_id")
	startTime := c.Query("start_time")
	endTime := c.Query("end_time")
	interval := c.DefaultQuery("interval", "1hour")

	if idParam == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "missing hex_id"})
		return
	}
	upper := strings.ToUpper(idParam)
	var b strings.Builder
	for i := 0; i < len(upper); i++ {
		ch := upper[i]
		if (ch >= '0' && ch <= '9') || (ch >= 'A' && ch <= 'F') {
			b.WriteByte(ch)
		}
	}
	hex := b.String()
	if hex == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid hex_id"})
		return
	}
	if len(hex) < 6 {
		hex = strings.Repeat("0", 6-len(hex)) + hex
	} else if len(hex) > 6 {
		hex = hex[len(hex)-6:]
	}
	stationID := fmt.Sprintf("RS485-%s", hex)

	loc, _ := time.LoadLocation("Asia/Shanghai")
	if loc == nil {
		loc = time.FixedZone("CST", 8*3600)
	}
	start, err := time.ParseInLocation("2006-01-02 15:04:05", startTime, loc)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid start_time"})
		return
	}
	end, err := time.ParseInLocation("2006-01-02 15:04:05", endTime, loc)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid end_time"})
		return
	}

	var points interface{}
	if interval == "raw" {
		points, err = data.SeriesRaw(stationID, start, end)
	} else {
		points, err = data.SeriesFrom10Min(stationID, start, end, interval)
	}
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("query failed: %v", err)})
		return
	}
	c.JSON(http.StatusOK, points)
}

func handleForecast(c *gin.Context) {
	stationID := c.Query("station_id")
	from := c.Query("from")
	to := c.Query("to")
	provider := c.Query("provider")
	versionsStr := c.DefaultQuery("versions", "1")
	versions, _ := strconv.Atoi(versionsStr)
	if versions <= 0 {
		versions = 1
	}

	if stationID == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "missing station_id"})
		return
	}

	loc, _ := time.LoadLocation("Asia/Shanghai")
	if loc == nil {
		loc = time.FixedZone("CST", 8*3600)
	}

	var start, end time.Time
	var err error
	if from == "" || to == "" {
		now := time.Now().In(loc)
		start = now.Truncate(time.Hour).Add(1 * time.Hour)
		end = start.Add(3 * time.Hour)
	} else {
		start, err = time.ParseInLocation("2006-01-02 15:04:05", from, loc)
		if err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid from"})
			return
		}
		end, err = time.ParseInLocation("2006-01-02 15:04:05", to, loc)
		if err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid to"})
			return
		}
	}

	points, err := data.Forecast(stationID, start, end, provider, versions)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("query forecast failed: %v", err)})
		return
	}
	c.JSON(http.StatusOK, points)
}

// handleForecastPerf 过去N天大雨预报表现
// GET /api/forecast/perf?station_id=RS485-XXXXXX&days=30&provider=imdroid_mix
func handleForecastPerf(c *gin.Context) {
	stationID := c.Query("station_id")
	if stationID == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "missing station_id"})
		return
	}
	daysStr := c.DefaultQuery("days", "30")
	provider := c.Query("provider")
	days, _ := strconv.Atoi(daysStr)
	if days <= 0 || days > 365 {
		days = 30
	}

	loc, _ := time.LoadLocation("Asia/Shanghai")
	if loc == nil {
		loc = time.FixedZone("CST", 8*3600)
	}
	now := time.Now().In(loc)
	since := now.AddDate(0, 0, -days)

	perf, err := data.HeavyRainPerf(stationID, since, provider)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("query perf failed: %v", err)})
		return
	}
	c.JSON(http.StatusOK, perf)
}

// handleTSPage renders a very simple HTML page to query TS metrics by station and compare providers (+1/+2/+3/mixed).
// Route: GET /TS?station_id=RS485-XXXXXX&start=YYYY-MM-DD+HH:MM:SS&end=YYYY-MM-DD+HH:MM:SS&threshold=0.1
func handleTSPage(c *gin.Context) {
	stationID := c.Query("station_id")
	startStr := c.Query("start")
	endStr := c.Query("end")
	thrStr := c.DefaultQuery("threshold", "0.1")
	providerSel := c.DefaultQuery("provider", "all")
	viewSel := c.DefaultQuery("view", "all")
	detailSel := c.DefaultQuery("detail", "none")

	loc, _ := time.LoadLocation("Asia/Shanghai")
	if loc == nil {
		loc = time.FixedZone("CST", 8*3600)
	}
	now := time.Now().In(loc)
	// defaults: last 30 days
	start := now.AddDate(0, 0, -30).Truncate(time.Hour)
	end := now.Truncate(time.Hour)
	if strings.TrimSpace(startStr) != "" {
		if t, err := time.ParseInLocation("2006-01-02 15:04:05", startStr, loc); err == nil {
			start = t
		}
	}
	if strings.TrimSpace(endStr) != "" {
		if t, err := time.ParseInLocation("2006-01-02 15:04:05", endStr, loc); err == nil {
			end = t
		}
	}
	if !end.After(start) {
		end = start.Add(24 * time.Hour)
	}
	thr, _ := strconv.ParseFloat(thrStr, 64)

	// Providers to compare or single
	allProviders := []string{"imdroid_V6", "imdroid_V5", "imdroid_mix", "caiyun", "open-meteo", "imdroid"}
	var providers []string
	if providerSel == "all" || strings.TrimSpace(providerSel) == "" {
		providers = allProviders
	} else {
		providers = []string{providerSel}
	}

	// Build HTML
	var b strings.Builder
	b.WriteString("<html><head><meta charset=\"utf-8\"></head><body>")
	b.WriteString("<h2>TS</h2>")
	b.WriteString("<form method='GET' action='/TS'>")
	b.WriteString("站点ID: <input type='text' name='station_id' value='" + htmlEscape(stationID) + "' style='width:180px'> ")
	b.WriteString("开始: <input type='text' name='start' value='" + start.Format("2006-01-02 15:04:05") + "' style='width:180px'> ")
	b.WriteString("结束: <input type='text' name='end' value='" + end.Format("2006-01-02 15:04:05") + "' style='width:180px'> ")
	// 阈值固定为默认值，不在页面提供输入框
	// provider select
	b.WriteString("预报源: <select name='provider'>")
	opts := append([]string{"all"}, allProviders...)
	for _, p := range opts {
		sel := ""
		if p == providerSel {
			sel = " selected"
		}
		b.WriteString("<option value='" + htmlEscape(p) + "'" + sel + ">" + htmlEscape(p) + "</option>")
	}
	b.WriteString("</select> ")
	// forecast point(select fixed lead or all)
	b.WriteString("预报点: <select name='view'>")
	viewOpts := []struct {
		v string
		n string
	}{{"all", "所有(+1/+2/+3)"}, {"lead1", "+1h"}, {"lead2", "+2h"}, {"lead3", "+3h"}}
	for _, it := range viewOpts {
		sel := ""
		if it.v == viewSel {
			sel = " selected"
		}
		b.WriteString("<option value='" + it.v + "'" + sel + ">" + it.n + "</option>")
	}
	b.WriteString("</select> ")
	// detail select
	b.WriteString("详细: <select name='detail'>")
	detOpts := []struct {
		v string
		n string
	}{{"none", "不显示"}, {"brief", "简略"}, {"detailed", "详细"}}
	for _, it := range detOpts {
		sel := ""
		if it.v == detailSel {
			sel = " selected"
		}
		b.WriteString("<option value='" + it.v + "'" + sel + ">" + it.n + "</option>")
	}
	b.WriteString("</select> ")
	b.WriteString("<button type='submit'>搜索</button></form>")
	// Helper: common station IDs for quick input
	b.WriteString("<div style='margin:8px 0;'>站点：</div>")
	b.WriteString("<table border='1' cellpadding='6' cellspacing='0'>")
	b.WriteString("<tr><th>station_id</th><th>location</th></tr>")
	b.WriteString("<tr><td>RS485-002A44</td><td>第二台气象站(伶俐镇那车1号大桥西北约324米)</td></tr>")
	b.WriteString("<tr><td>RS485-0029CD</td><td>第四台气象站(宾阳县宾州镇塘山2号大桥西北约293米)</td></tr>")
	b.WriteString("<tr><td>RS485-0029CA</td><td>第五台气象站(宾阳县陈平镇和平3号大桥东北约197米)</td></tr>")
	b.WriteString("<tr><td>RS485-0029C3</td><td>第七台气象站(宾阳县细塘村东南约112米)</td></tr>")
	b.WriteString("<tr><td>RS485-002A30</td><td>第八台气象站(宾阳县松塘村西南约161米)</td></tr>")
	b.WriteString("<tr><td>RS485-002964</td><td>兴山县一号气象站(湖北省宜昌市兴山县昭君镇贺家院子东北约484米)</td></tr>")
	b.WriteString("<tr><td>RS485-002A39</td><td>兴山县二号气象站(湖北省宜昌市兴山县昭君镇黄家堑东北约244米)</td></tr>")
	b.WriteString("<tr><td>RS485-002A69</td><td>第一台气象站(宾阳县陈平镇大平村西南约325米)(V6使用彩云为基础数据)</td></tr>")
	b.WriteString("<tr><td>RS485-002A7B</td><td>第三台气象站(宾阳县细坡西南约263米)(V6使用彩云为基础数据)</td></tr>")
	b.WriteString("</table><hr/>")

	if strings.TrimSpace(stationID) == "" {
		b.WriteString("</body></html>")
		c.Data(http.StatusOK, "text/html; charset=utf-8", []byte(b.String()))
		return
	}

	// header + legend
	b.WriteString("<div>时间窗: " + start.Format("2006-01-02 15:04:05") + " ~ " + end.Format("2006-01-02 15:04:05") + "</div>")
	b.WriteString("<div style='margin:6px 0;color:#444;'>说明：n 为样本数；n11 为预报降雨且实况降雨（Hit）；n01 为预报不降雨但实况降雨（漏报）；n10 为预报降雨但实况不降雨（误报）；n00 为预报与实况均不降雨。CSI 为临界成功指数，POD 为命中率，FAR 为误报率。</div>")
	b.WriteString("<table border='1' cellpadding='6' cellspacing='0'>")
	b.WriteString("<tr><th>Provider</th><th>预报点</th><th>n</th><th>n11</th><th>n01</th><th>n10</th><th>n00</th><th>CSI</th><th>POD</th><th>FAR</th></tr>")

	addRow := func(pv, view string, s data.BinaryScores) {
		b.WriteString(fmt.Sprintf("<tr><td>%s</td><td>%s</td><td>%d</td><td>%d</td><td>%d</td><td>%d</td><td>%d</td><td>%.3f</td><td>%.3f</td><td>%.3f</td></tr>",
			htmlEscape(pv), htmlEscape(view), s.N, s.N11, s.N01, s.N10, s.N00, s.CSI, s.POD, s.FAR))
	}

	var renderScores func(pv, view string)
	renderScores = func(pv, view string) {
		switch view {
		case "lead1":
			if s, err := data.ForecastBinaryScoresLead(stationID, start, end, pv, thr, 1); err == nil {
				addRow(pv, "+1h", s)
			} else {
				addRow(pv, "+1h", data.BinaryScores{})
			}
		case "lead2":
			if s, err := data.ForecastBinaryScoresLead(stationID, start, end, pv, thr, 2); err == nil {
				addRow(pv, "+2h", s)
			} else {
				addRow(pv, "+2h", data.BinaryScores{})
			}
		case "lead3":
			if s, err := data.ForecastBinaryScoresLead(stationID, start, end, pv, thr, 3); err == nil {
				addRow(pv, "+3h", s)
			} else {
				addRow(pv, "+3h", data.BinaryScores{})
			}
		case "all":
			renderScores(pv, "lead1")
			renderScores(pv, "lead2")
			renderScores(pv, "lead3")
		}
	}
	for _, pv := range providers {
		renderScores(pv, viewSel)
	}
	b.WriteString("</table>")

	// detail view only when a single provider and single view selected
	if providerSel != "all" && viewSel != "all" && (detailSel == "brief" || detailSel == "detailed") {
		var rows []data.BinaryRow
		var err error
		switch viewSel {
		case "lead1":
			rows, err = data.ForecastBinarySeriesLead(stationID, start, end, providerSel, 1)
		case "lead2":
			rows, err = data.ForecastBinarySeriesLead(stationID, start, end, providerSel, 2)
		case "lead3":
			rows, err = data.ForecastBinarySeriesLead(stationID, start, end, providerSel, 3)
		}
		if err == nil {
			b.WriteString("<h3>明细 (" + htmlEscape(providerSel) + ", " + htmlEscape(viewSel) + ")</h3>")
			b.WriteString("<table border='1' cellpadding='6' cellspacing='0'>")
			b.WriteString("<tr><th>编号</th><th>时间</th><th>实况(mm)</th><th>预报(mm)</th><th>发生?</th><th>命中?</th></tr>")
			var n, n11, n01, n10, n00 int64
			idx := 0
			for _, r := range rows {
				actualEvt := r.ActualMM > thr
				predEvt := r.PredMM > thr
				if detailSel == "brief" && !(actualEvt || predEvt) {
					continue
				}
				idx++
				n++
				if predEvt && actualEvt {
					n11++
				} else if !predEvt && actualEvt {
					n01++
				} else if predEvt && !actualEvt {
					n10++
				} else {
					n00++
				}
				hit := "否"
				if predEvt && actualEvt {
					hit = "是"
				}
				b.WriteString(fmt.Sprintf("<tr><td>%d</td><td>%s</td><td>%.3f</td><td>%.3f</td><td>%s</td><td>%s</td></tr>", idx, r.T.Format("2006-01-02 15:04:05"), r.ActualMM, r.PredMM, boolCN(actualEvt), hit))
			}
			var csi, pod, far float64
			h, m, f := float64(n11), float64(n01), float64(n10)
			if (h + m + f) > 0 {
				csi = h / (h + m + f)
			}
			if (h + m) > 0 {
				pod = h / (h + m)
			}
			if (h + f) > 0 {
				far = f / (h + f)
			}
			b.WriteString("</table>")
			b.WriteString(fmt.Sprintf("<div>统计: n=%d n11=%d n01=%d n10=%d n00=%d | CSI=%.3f POD=%.3f FAR=%.3f</div>", n, n11, n01, n10, n00, csi, pod, far))
		}
	}
	b.WriteString("</body></html>")
	c.Data(http.StatusOK, "text/html; charset=utf-8", []byte(b.String()))
}

func htmlEscape(s string) string {
	r := strings.NewReplacer("&", "&amp;", "<", "&lt;", ">", "&gt;", "\"", "&quot;", "'", "&#39;")
	return r.Replace(s)
}

func boolCN(b bool) string {
	if b {
		return "是"
	}
	return "否"
}

// handleForecastScores 过去N天的二分类评分（TS/CSI, POD, FAR）
// GET /api/forecast/scores?station_id=RS485-XXXXXX&days=30&provider=imdroid_mix&threshold=0
func handleForecastScores(c *gin.Context) {
	stationID := c.Query("station_id")
	if stationID == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "missing station_id"})
		return
	}
	daysStr := c.DefaultQuery("days", "30")
	provider := c.Query("provider")
	thrStr := c.DefaultQuery("threshold", "0")
	days, _ := strconv.Atoi(daysStr)
	if days <= 0 || days > 365 {
		days = 30
	}
	thresholdMM, _ := strconv.ParseFloat(thrStr, 64)

	loc, _ := time.LoadLocation("Asia/Shanghai")
	if loc == nil {
		loc = time.FixedZone("CST", 8*3600)
	}
	now := time.Now().In(loc)
	since := now.AddDate(0, 0, -days)

	scores, err := data.ForecastBinaryScores(stationID, since, now, provider, thresholdMM)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("query scores failed: %v", err)})
		return
	}
	c.JSON(http.StatusOK, scores)
}