package controlplane

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

// AgentDirectoryFilter is a bounded, server-side filter for the Agent directory.
// Empty values mean "all"; it deliberately has no free-form SQL fields.
type AgentDirectoryFilter struct {
	Page             int    `json:"page"`
	PageSize         int    `json:"pageSize"`
	Name             string `json:"name"`
	ConnectionStatus string `json:"connectionStatus"`
	MCPStatus        string `json:"mcpStatus"`
	LLMStatus        string `json:"llmStatus"`
	SkillStatus      string `json:"skillStatus"`
}

// AgentDirectoryItem is the safe, one-row operational summary used in a paged list.
type AgentDirectoryItem struct {
	ID               string `json:"id"`
	Name             string `json:"name"`
	Status           string `json:"status"`
	LastSeenAt       string `json:"lastSeenAt"`
	LLMProfile       string `json:"llmProfile"`
	LLMStatus        string `json:"llmStatus"`
	LLMFailure       string `json:"llmFailure"`
	SkillTotal       int    `json:"skillTotal"`
	SkillApplied     int    `json:"skillApplied"`
	SkillStatus      string `json:"skillStatus"`
	SkillFailure     string `json:"skillFailure"`
	MCPStatus        string `json:"mcpStatus"`
	MCPFailure       string `json:"mcpFailure"`
	LastDeploymentAt string `json:"lastDeploymentAt"`
	RestartStatus    string `json:"restartStatus"`
	RestartFailure   string `json:"restartFailure"`
}

type AgentDirectoryPage struct {
	Items      []AgentDirectoryItem `json:"items"`
	Page       int                  `json:"page"`
	PageSize   int                  `json:"pageSize"`
	TotalItems int                  `json:"totalItems"`
	TotalPages int                  `json:"totalPages"`
}

type DeploymentFailure struct {
	Resource  string `json:"resource"`
	Reason    string `json:"reason"`
	UpdatedAt string `json:"updatedAt"`
}

// AgentOperationalDetail keeps the detail view intentionally operational: recent
// tasks, safe audit/deployment trail and current deployment failures only.
type AgentOperationalDetail struct {
	Agent             Agent               `json:"agent"`
	Deployment        AgentDirectoryItem  `json:"deployment"`
	RecentTasks       []Task              `json:"recentTasks"`
	RecentAudit       []AuditEvent        `json:"recentAudit"`
	DeploymentHistory []AuditEvent        `json:"deploymentHistory"`
	Failures          []DeploymentFailure `json:"failures"`
}

var agentDirectoryBaseSQL = `WITH skill_summary AS (
	SELECT agent_id, COUNT(*) AS total,
	SUM(CASE WHEN apply_status = 'applied' THEN 1 ELSE 0 END) AS applied,
	SUM(CASE WHEN apply_status = 'failed' THEN 1 ELSE 0 END) AS failed,
	SUM(CASE WHEN apply_status = 'pending' THEN 1 ELSE 0 END) AS pending,
	SUM(CASE WHEN apply_status = 'sent' THEN 1 ELSE 0 END) AS sent,
	MAX(updated_at) AS updated_at,
	MAX(CASE WHEN apply_status = 'failed' THEN last_error ELSE '' END) AS failure
	FROM agent_skill_assignments GROUP BY agent_id
), directory AS (
	SELECT a.agent_id, a.name, a.status, a.last_seen_at,
	COALESCE(p.name, '') AS llm_profile, COALESCE(l.apply_status, '未部署') AS llm_status,
	COALESCE(l.last_error, '') AS llm_failure,
	COALESCE(s.total, 0) AS skill_total, COALESCE(s.applied, 0) AS skill_applied,
	CASE WHEN COALESCE(s.total, 0) = 0 THEN '未选择'
		WHEN COALESCE(s.failed, 0) > 0 THEN 'failed'
		WHEN COALESCE(s.pending, 0) > 0 THEN 'pending'
		WHEN COALESCE(s.sent, 0) > 0 THEN 'sent'
		ELSE 'applied' END AS skill_status,
	COALESCE(s.failure, '') AS skill_failure,
	` + mcpStatusExpression("a.agent_id") + ` AS mcp_status,
	` + mcpErrorExpression("a.agent_id") + ` AS mcp_failure,
	COALESCE((SELECT MAX(updated_at) FROM agent_mcp_assignments m WHERE m.agent_id = a.agent_id), '') AS mcp_updated_at,
	MAX(COALESCE(l.updated_at, ''), COALESCE((SELECT MAX(updated_at) FROM agent_mcp_assignments m WHERE m.agent_id = a.agent_id), ''), COALESCE(s.updated_at, '')) AS last_deployment_at,
	COALESCE(r.status, '') AS restart_status, COALESCE(r.failure, '') AS restart_failure
	FROM managed_agents a
	LEFT JOIN agent_llm_assignments l ON l.agent_id = a.agent_id
	LEFT JOIN llm_profiles p ON p.profile_id = l.profile_id
	LEFT JOIN skill_summary s ON s.agent_id = a.agent_id
	LEFT JOIN agent_restart_operations r ON r.agent_id = a.agent_id
)
`

func normaliseAgentDirectoryFilter(filter AgentDirectoryFilter) (AgentDirectoryFilter, error) {
	filter.Name = strings.TrimSpace(filter.Name)
	filter.ConnectionStatus = strings.TrimSpace(filter.ConnectionStatus)
	filter.MCPStatus = strings.TrimSpace(filter.MCPStatus)
	filter.LLMStatus = strings.TrimSpace(filter.LLMStatus)
	filter.SkillStatus = strings.TrimSpace(filter.SkillStatus)
	if len([]rune(filter.Name)) > 80 {
		return filter, errors.New("Agent 名称搜索不能超过 80 个字符")
	}
	if filter.Page < 1 {
		filter.Page = 1
	}
	if filter.PageSize < 1 {
		filter.PageSize = 12
	}
	if filter.PageSize > 50 {
		filter.PageSize = 50
	}
	if !oneOf(filter.ConnectionStatus, "", "online", "offline") ||
		!oneOf(filter.MCPStatus, "", "未启用", "pending", "sent", "applied", "failed") ||
		!oneOf(filter.LLMStatus, "", "未部署", "pending", "sent", "applied", "failed") ||
		!oneOf(filter.SkillStatus, "", "未选择", "pending", "sent", "applied", "failed") {
		return filter, errors.New("Agent 筛选条件无效")
	}
	return filter, nil
}

func oneOf(value string, allowed ...string) bool {
	for _, candidate := range allowed {
		if value == candidate {
			return true
		}
	}
	return false
}

func agentDirectoryWhere(filter AgentDirectoryFilter) (string, []any) {
	clauses, args := make([]string, 0, 5), make([]any, 0, 5)
	if filter.Name != "" {
		escaped := strings.NewReplacer("\\", "\\\\", "%", "\\%", "_", "\\_").Replace(filter.Name)
		clauses, args = append(clauses, "name LIKE ? ESCAPE '\\'"), append(args, "%"+escaped+"%")
	}
	for _, criterion := range []struct{ column, value string }{{"status", filter.ConnectionStatus}, {"mcp_status", filter.MCPStatus}, {"llm_status", filter.LLMStatus}, {"skill_status", filter.SkillStatus}} {
		if criterion.value != "" {
			clauses, args = append(clauses, criterion.column+" = ?"), append(args, criterion.value)
		}
	}
	if len(clauses) == 0 {
		return "", args
	}
	return " WHERE " + strings.Join(clauses, " AND "), args
}

// AgentDirectory provides database pagination and all Agent filters in one query.
func (c *ControlPlane) AgentDirectory(filter AgentDirectoryFilter) (AgentDirectoryPage, error) {
	c.expireStaleAgents()
	filter, err := normaliseAgentDirectoryFilter(filter)
	if err != nil {
		return AgentDirectoryPage{}, err
	}
	where, args := agentDirectoryWhere(filter)
	page := AgentDirectoryPage{Items: make([]AgentDirectoryItem, 0), Page: filter.Page, PageSize: filter.PageSize}
	if err := c.db.QueryRow(agentDirectoryBaseSQL+"SELECT COUNT(*) FROM directory"+where, args...).Scan(&page.TotalItems); err != nil {
		return page, fmt.Errorf("无法统计 Agent 列表: %w", err)
	}
	page.TotalPages = (page.TotalItems + filter.PageSize - 1) / filter.PageSize
	if page.TotalPages > 0 && page.Page > page.TotalPages {
		page.Page = page.TotalPages
	}
	queryArgs := append(append([]any{}, args...), filter.PageSize, (page.Page-1)*filter.PageSize)
	rows, err := c.db.Query(agentDirectoryBaseSQL+`SELECT agent_id, name, status, last_seen_at, llm_profile, llm_status, llm_failure,
		skill_total, skill_applied, skill_status, skill_failure, mcp_status, mcp_failure, last_deployment_at, restart_status, restart_failure
		FROM directory`+where+" ORDER BY CASE status WHEN 'online' THEN 0 ELSE 1 END, name COLLATE NOCASE, agent_id LIMIT ? OFFSET ?", queryArgs...)
	if err != nil {
		return page, fmt.Errorf("无法读取 Agent 列表: %w", err)
	}
	defer rows.Close()
	for rows.Next() {
		var item AgentDirectoryItem
		if err := rows.Scan(&item.ID, &item.Name, &item.Status, &item.LastSeenAt, &item.LLMProfile, &item.LLMStatus, &item.LLMFailure, &item.SkillTotal, &item.SkillApplied, &item.SkillStatus, &item.SkillFailure, &item.MCPStatus, &item.MCPFailure, &item.LastDeploymentAt, &item.RestartStatus, &item.RestartFailure); err != nil {
			return page, err
		}
		item.LLMFailure, item.SkillFailure, item.MCPFailure = sanitizeDisplayText(item.LLMFailure), sanitizeDisplayText(item.SkillFailure), sanitizeDisplayText(item.MCPFailure)
		page.Items = append(page.Items, item)
	}
	return page, rows.Err()
}

// AgentOperationalDetails returns bounded, safe operational context for one Agent.
func (c *ControlPlane) AgentOperationalDetails(agentID string) (AgentOperationalDetail, error) {
	if strings.TrimSpace(agentID) == "" {
		return AgentOperationalDetail{}, errors.New("Agent 标识无效")
	}
	// Fetch by ID directly so duplicate display names cannot select another Agent.
	var item AgentDirectoryItem
	err := c.db.QueryRow(agentDirectoryBaseSQL+`SELECT agent_id, name, status, last_seen_at, llm_profile, llm_status, llm_failure,
		skill_total, skill_applied, skill_status, skill_failure, mcp_status, mcp_failure, last_deployment_at, restart_status, restart_failure FROM directory WHERE agent_id = ?`, agentID).Scan(
		&item.ID, &item.Name, &item.Status, &item.LastSeenAt, &item.LLMProfile, &item.LLMStatus, &item.LLMFailure, &item.SkillTotal, &item.SkillApplied, &item.SkillStatus, &item.SkillFailure, &item.MCPStatus, &item.MCPFailure, &item.LastDeploymentAt, &item.RestartStatus, &item.RestartFailure,
	)
	if errors.Is(err, sql.ErrNoRows) {
		return AgentOperationalDetail{}, errors.New("未找到 Agent")
	}
	if err != nil {
		return AgentOperationalDetail{}, fmt.Errorf("无法读取 Agent 详情: %w", err)
	}
	detail := AgentOperationalDetail{Agent: Agent{ID: item.ID, Name: item.Name, Status: item.Status, LastSeenAt: item.LastSeenAt, RestartStatus: item.RestartStatus, RestartFailure: item.RestartFailure}, Deployment: item, RecentTasks: make([]Task, 0), RecentAudit: make([]AuditEvent, 0), DeploymentHistory: make([]AuditEvent, 0), Failures: make([]DeploymentFailure, 0)}
	detail.RecentTasks, err = c.recentTasksForAgent(agentID, 8)
	if err != nil {
		return detail, err
	}
	detail.RecentAudit, err = c.agentAuditEvents(agentID, false, 12)
	if err != nil {
		return detail, err
	}
	detail.DeploymentHistory, err = c.agentAuditEvents(agentID, true, 12)
	if err != nil {
		return detail, err
	}
	for _, failure := range []DeploymentFailure{{"LLM", item.LLMFailure, item.LastDeploymentAt}, {"Skill", item.SkillFailure, item.LastDeploymentAt}, {"MCP", item.MCPFailure, item.LastDeploymentAt}} {
		if strings.TrimSpace(failure.Reason) != "" {
			failure.Reason = sanitizeDisplayText(failure.Reason)
			detail.Failures = append(detail.Failures, failure)
		}
	}
	return detail, nil
}

func (c *ControlPlane) recentTasksForAgent(agentID string, maximum int) ([]Task, error) {
	rows, err := c.db.Query("SELECT task_id, agent_id, COALESCE(NULLIF(agent_name, ''), '未知 Agent'), instruction, status, created_at, COALESCE(started_at, ''), COALESCE(finished_at, ''), COALESCE(deadline_at, ''), COALESCE(attempt, 1), COALESCE(retry_of, ''), COALESCE(output, ''), COALESCE(error, ''), COALESCE(execution_source, ''), COALESCE(session_id, '') FROM task_runs WHERE agent_id = ? ORDER BY created_at DESC LIMIT ?", agentID, maximum)
	if err != nil {
		return nil, fmt.Errorf("无法读取 Agent 最近任务: %w", err)
	}
	defer rows.Close()
	tasks := make([]Task, 0)
	for rows.Next() {
		var task Task
		if err := rows.Scan(&task.ID, &task.AgentID, &task.AgentName, &task.Instruction, &task.Status, &task.CreatedAt, &task.StartedAt, &task.FinishedAt, &task.DeadlineAt, &task.Attempt, &task.RetryOf, &task.Output, &task.Error, &task.Execution, &task.SessionID); err != nil {
			return nil, err
		}
		tasks = append(tasks, task)
	}
	return tasks, rows.Err()
}

func (c *ControlPlane) agentAuditEvents(agentID string, deploymentOnly bool, maximum int) ([]AuditEvent, error) {
	where := "(actor = ? OR target LIKE ?)"
	args := []any{"agent:" + agentID, "agent:" + agentID + "%"}
	if deploymentOnly {
		where += " AND (action LIKE 'llm.%' OR action LIKE 'skill.%' OR action LIKE 'mcp.%')"
	}
	rows, err := c.db.Query("SELECT event_id, action, actor, target, outcome, detail, created_at FROM audit_events WHERE "+where+" ORDER BY event_id DESC LIMIT ?", append(args, maximum)...)
	if err != nil {
		return nil, fmt.Errorf("无法读取 Agent 审计记录: %w", err)
	}
	defer rows.Close()
	events := make([]AuditEvent, 0)
	for rows.Next() {
		var event AuditEvent
		if err := rows.Scan(&event.ID, &event.Action, &event.Actor, &event.Target, &event.Outcome, &event.Detail, &event.CreatedAt); err != nil {
			return nil, err
		}
		event.Detail = sanitizeDisplayText(event.Detail)
		events = append(events, event)
	}
	return events, rows.Err()
}