package operations

import (
	"context"
	"net/http"
	"runtime"
	"strconv"
	"time"

	"aigateway.local/core/internal/identity"
	"aigateway.local/core/internal/platform/apiresponse"
	"aigateway.local/core/internal/platform/oplog"
	"github.com/jackc/pgx/v5/pgxpool"
)

type AdminHTTPHandler struct {
	pool      *pgxpool.Pool
	identity  *identity.Service
	version   string
	startedAt time.Time
	reload    func(context.Context) error
	mux       *http.ServeMux
}

func NewAdminHTTPHandler(pool *pgxpool.Pool, identityService *identity.Service, version string, startedAt time.Time, reload func(context.Context) error) *AdminHTTPHandler {
	h := &AdminHTTPHandler{pool: pool, identity: identityService, version: version, startedAt: startedAt, reload: reload, mux: http.NewServeMux()}
	h.mux.HandleFunc("GET /api/v1/admin/system-info", h.systemInfo)
	h.mux.HandleFunc("GET /api/v1/admin/monitoring/overview", h.overview)
	h.mux.HandleFunc("GET /api/v1/admin/tenants/overview", h.tenantsOverview)
	h.mux.HandleFunc("GET /api/v1/admin/reports/tools", h.reportTools)
	h.mux.HandleFunc("GET /api/v1/admin/reports/approvals", h.reportApprovals)
	h.mux.HandleFunc("GET /api/v1/admin/reports/security", h.reportSecurity)
	h.mux.HandleFunc("GET /api/v1/admin/op-logs", h.opLogs)
	h.mux.HandleFunc("POST /api/v1/admin/reload", h.reloadSnapshots)
	return h
}

// opLogs 查询管理操作审计(操作者/操作类型过滤 + 分页)。
func (h *AdminHTTPHandler) opLogs(w http.ResponseWriter, r *http.Request) {
	if _, ok := h.requirePermission(w, r, identity.PermissionAuditRead); !ok {
		return
	}
	limit, _ := strconv.Atoi(r.URL.Query().Get("limit"))
	if limit < 1 || limit > 200 {
		limit = 50
	}
	offset, _ := strconv.Atoi(r.URL.Query().Get("offset"))
	if offset < 0 {
		offset = 0
	}
	items, total, err := oplog.List(r.Context(), h.pool, r.URL.Query().Get("actor"), r.URL.Query().Get("action"), limit, offset)
	if err != nil {
		apiresponse.Error(w, http.StatusServiceUnavailable, "操作审计查询失败")
		return
	}
	apiresponse.OK(w, map[string]any{"items": items, "total": total, "limit": limit, "offset": offset})
}

func (h *AdminHTTPHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) { h.mux.ServeHTTP(w, r) }

func (h *AdminHTTPHandler) account(w http.ResponseWriter, r *http.Request) (identity.Account, bool) {
	account, err := h.identity.Authenticate(r.Context(), identity.KindAdmin, r.Header.Get("Authorization"))
	if err != nil {
		apiresponse.Error(w, http.StatusUnauthorized, "登录状态无效")
		return identity.Account{}, false
	}
	return account, true
}

func (h *AdminHTTPHandler) requirePermission(w http.ResponseWriter, r *http.Request, permission string) (identity.Account, bool) {
	account, ok := h.account(w, r)
	if !ok {
		return account, false
	}
	if !identity.HasPermission(account, permission) {
		apiresponse.Error(w, http.StatusForbidden, "缺少权限")
		return identity.Account{}, false
	}
	return account, true
}

func (h *AdminHTTPHandler) systemInfo(w http.ResponseWriter, r *http.Request) {
	if _, ok := h.requirePermission(w, r, identity.PermissionSystemManage); !ok {
		return
	}
	var providers, models, keys int64
	if err := h.pool.QueryRow(r.Context(), `SELECT (SELECT count(*) FROM gateway.providers WHERE enabled),(SELECT count(*) FROM gateway.provider_models WHERE enabled),(SELECT count(*) FROM gateway.api_keys WHERE enabled)`).Scan(&providers, &models, &keys); err != nil {
		apiresponse.Error(w, http.StatusServiceUnavailable, "系统信息查询失败")
		return
	}
	apiresponse.OK(w, map[string]any{"version": h.version, "go_version": runtime.Version(), "uptime_seconds": int64(time.Since(h.startedAt).Seconds()), "database": "postgresql", "object_storage": true, "clickhouse": false, "enabled_providers": providers, "enabled_models": models, "enabled_api_keys": keys})
}

func (h *AdminHTTPHandler) overview(w http.ResponseWriter, r *http.Request) {
	if _, ok := h.requirePermission(w, r, identity.PermissionUsageRead); !ok {
		return
	}
	var requests, failures, promptTokens, completionTokens, cost int64
	var latency *float64
	err := h.pool.QueryRow(r.Context(), `SELECT count(*),count(*) FILTER(WHERE coalesce(status_code,500)>=400),coalesce(sum(prompt_tokens),0),coalesce(sum(completion_tokens),0),coalesce(sum(cost_microunits),0),avg(latency_ms) FROM gateway.audit_events WHERE recorded_at>=clock_timestamp()-interval '24 hours'`).Scan(&requests, &failures, &promptTokens, &completionTokens, &cost, &latency)
	if err != nil {
		apiresponse.Error(w, http.StatusServiceUnavailable, "监控汇总查询失败")
		return
	}
	apiresponse.OK(w, map[string]any{"window": "24h", "requests": requests, "failed_requests": failures, "prompt_tokens": promptTokens, "completion_tokens": completionTokens, "cost_microunits": cost, "avg_latency_ms": latency})
}

func (h *AdminHTTPHandler) reloadSnapshots(w http.ResponseWriter, r *http.Request) {
	account, ok := h.account(w, r)
	if !ok {
		return
	}
	if !identity.HasPermission(account, identity.PermissionProviderManage) {
		apiresponse.Error(w, http.StatusForbidden, "缺少运行时配置管理权限")
		return
	}
	if h.reload != nil {
		if err := h.reload(r.Context()); err != nil {
			apiresponse.Error(w, http.StatusServiceUnavailable, "运行时快照刷新不完整，请查看服务端日志")
			return
		}
	}
	apiresponse.OK(w, map[string]bool{"reloaded": true})
}

// tenantsOverview 以部门为租户维度,汇总各租户的账号/Key/用量与配额。
func (h *AdminHTTPHandler) tenantsOverview(w http.ResponseWriter, r *http.Request) {
	if _, ok := h.requirePermission(w, r, identity.PermissionUsageRead); !ok {
		return
	}
	rows, err := h.pool.Query(r.Context(), `SELECT d.id::text,d.name,d.max_api_keys,d.max_monthly_tokens,
		(SELECT count(*) FROM gateway.portal_users u WHERE u.department_id=d.id),
		(SELECT count(*) FROM gateway.api_keys k WHERE k.tenant_id=d.id AND k.enabled),
		(SELECT count(*) FROM gateway.audit_events a WHERE a.tenant_id=d.id AND a.recorded_at>=date_trunc('day',now())),
		(SELECT COALESCE(sum(a.prompt_tokens+a.completion_tokens),0) FROM gateway.audit_events a WHERE a.tenant_id=d.id AND a.recorded_at>=date_trunc('day',now())),
		(SELECT COALESCE(sum(a.prompt_tokens+a.completion_tokens),0) FROM gateway.audit_events a WHERE a.tenant_id=d.id AND a.recorded_at>=date_trunc('month',now()))
		FROM gateway.departments d WHERE d.active ORDER BY d.name`)
	if err != nil {
		apiresponse.Error(w, http.StatusServiceUnavailable, "租户概览查询失败")
		return
	}
	defer rows.Close()
	type tenantRow struct {
		ID               string `json:"id"`
		Name             string `json:"name"`
		MaxAPIKeys       int64  `json:"max_api_keys"`
		MaxMonthlyTokens int64  `json:"max_monthly_tokens"`
		PortalUsers      int64  `json:"portal_users"`
		EnabledKeys      int64  `json:"enabled_api_keys"`
		TodayRequests    int64  `json:"today_requests"`
		TodayTokens      int64  `json:"today_tokens"`
		MonthTokens      int64  `json:"month_tokens"`
	}
	items := []tenantRow{}
	for rows.Next() {
		var item tenantRow
		if err := rows.Scan(&item.ID, &item.Name, &item.MaxAPIKeys, &item.MaxMonthlyTokens, &item.PortalUsers, &item.EnabledKeys, &item.TodayRequests, &item.TodayTokens, &item.MonthTokens); err != nil {
			apiresponse.Error(w, http.StatusServiceUnavailable, "租户概览查询失败")
			return
		}
		items = append(items, item)
	}
	if err := rows.Err(); err != nil {
		apiresponse.Error(w, http.StatusServiceUnavailable, "租户概览查询失败")
		return
	}
	apiresponse.OK(w, map[string]any{"tenants": items})
}

// reportRange 解析 from/to 日期(YYYY-MM-DD),返回起止时间。
func (h *AdminHTTPHandler) reportRange(r *http.Request) (from, to time.Time) {
	now := time.Now().UTC()
	to = now
	from = now.AddDate(0, 0, -6)
	if value := r.URL.Query().Get("from"); value != "" {
		if parsed, err := time.Parse("2006-01-02", value); err == nil {
			from = parsed
		}
	}
	if value := r.URL.Query().Get("to"); value != "" {
		if parsed, err := time.Parse("2006-01-02", value); err == nil {
			to = parsed.AddDate(0, 0, 1)
		}
	}
	return from, to
}

// reportTools 工具维度统计:调用数/成功率/平均延迟。
func (h *AdminHTTPHandler) reportTools(w http.ResponseWriter, r *http.Request) {
	if _, ok := h.requirePermission(w, r, identity.PermissionUsageRead); !ok {
		return
	}
	from, to := h.reportRange(r)
	rows, err := h.pool.Query(r.Context(), `SELECT t.code,t.name,
		count(r.id),
		count(r.id) FILTER (WHERE r.status='success'),
		COALESCE(avg(r.latency_ms),0)::bigint
		FROM gateway.tool_runs r JOIN gateway.tool_definitions t ON t.id=r.tool_id
		WHERE r.created_at>=$1 AND r.created_at<$2
		GROUP BY t.code,t.name ORDER BY count(r.id) DESC LIMIT 100`, from, to)
	if err != nil {
		apiresponse.Error(w, http.StatusServiceUnavailable, "工具报表查询失败")
		return
	}
	defer rows.Close()
	items := []map[string]any{}
	for rows.Next() {
		var code, name string
		var total, success, avgLatency int64
		if err := rows.Scan(&code, &name, &total, &success, &avgLatency); err != nil {
			apiresponse.Error(w, http.StatusServiceUnavailable, "工具报表查询失败")
			return
		}
		items = append(items, map[string]any{"code": code, "name": name, "requests": total, "success": success, "failed": total - success, "avg_latency_ms": avgLatency})
	}
	apiresponse.OK(w, items)
}

// reportApprovals 审批维度统计:模型/资源/工具申请的发起与审批结果。
func (h *AdminHTTPHandler) reportApprovals(w http.ResponseWriter, r *http.Request) {
	if _, ok := h.requirePermission(w, r, identity.PermissionUsageRead); !ok {
		return
	}
	from, to := h.reportRange(r)
	rows, err := h.pool.Query(r.Context(), `SELECT 'model' AS kind,status,count(*) FROM gateway.model_access_requests WHERE created_at>=$1 AND created_at<$2 GROUP BY status
		UNION ALL SELECT 'resource',status,count(*) FROM gateway.resource_access_requests WHERE created_at>=$1 AND created_at<$2 GROUP BY status
		UNION ALL SELECT 'tool',status,count(*) FROM gateway.tool_approval_requests WHERE created_at>=$1 AND created_at<$2 GROUP BY status`, from, to)
	if err != nil {
		apiresponse.Error(w, http.StatusServiceUnavailable, "审批报表查询失败")
		return
	}
	defer rows.Close()
	items := []map[string]any{}
	for rows.Next() {
		var kind, status string
		var count int64
		if err := rows.Scan(&kind, &status, &count); err != nil {
			apiresponse.Error(w, http.StatusServiceUnavailable, "审批报表查询失败")
			return
		}
		items = append(items, map[string]any{"kind": kind, "status": status, "count": count})
	}
	apiresponse.OK(w, items)
}

// reportSecurity 安全维度统计:登录成功/失败、锁定与来源 IP 分布。
func (h *AdminHTTPHandler) reportSecurity(w http.ResponseWriter, r *http.Request) {
	if _, ok := h.requirePermission(w, r, identity.PermissionAuditRead); !ok {
		return
	}
	from, to := h.reportRange(r)
	rows, err := h.pool.Query(r.Context(), `SELECT success,count(*),count(DISTINCT ip) FROM gateway.login_logs WHERE created_at>=$1 AND created_at<$2 GROUP BY success
		UNION ALL SELECT NULL,0,0 WHERE false`, from, to)
	if err != nil {
		apiresponse.Error(w, http.StatusServiceUnavailable, "安全报表查询失败")
		return
	}
	defer rows.Close()
	type loginStat struct {
		Success     bool  `json:"success"`
		Count       int64 `json:"count"`
		DistinctIPs int64 `json:"distinct_ips"`
	}
	stats := []loginStat{}
	for rows.Next() {
		var item loginStat
		if err := rows.Scan(&item.Success, &item.Count, &item.DistinctIPs); err != nil {
			apiresponse.Error(w, http.StatusServiceUnavailable, "安全报表查询失败")
			return
		}
		stats = append(stats, item)
	}
	rows.Close()
	ips, err := h.pool.Query(r.Context(), `SELECT ip::text,count(*) FROM gateway.login_logs WHERE created_at>=$1 AND created_at<$2 GROUP BY ip ORDER BY count(*) DESC LIMIT 10`, from, to)
	if err != nil {
		apiresponse.Error(w, http.StatusServiceUnavailable, "安全报表查询失败")
		return
	}
	defer ips.Close()
	topIPs := []map[string]any{}
	for ips.Next() {
		var ip string
		var count int64
		if err := ips.Scan(&ip, &count); err != nil {
			apiresponse.Error(w, http.StatusServiceUnavailable, "安全报表查询失败")
			return
		}
		topIPs = append(topIPs, map[string]any{"ip": ip, "count": count})
	}
	apiresponse.OK(w, map[string]any{"login_stats": stats, "top_ips": topIPs})
}